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Groups > linux.kernel > #1645017 > unrolled thread
| Started by | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| First post | 2017-05-19 03:30 +0200 |
| Last post | 2017-05-19 03:50 +0200 |
| Articles | 20 on this page of 32 — 3 participants |
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[PATCH 00/31] Standardize doc formats - part 1 Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:30 +0200
[PATCH 16/31] DMA-attributes.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:30 +0200
[PATCH 27/31] intel_txt.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:30 +0200
[PATCH 26/31] hwspinlock.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:30 +0200
[PATCH 13/31] digsig.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:30 +0200
[PATCH 19/31] efi-stub.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 28/31] Intel-IOMMU.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 06/31] cgroup-v2.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
Re: [PATCH 06/31] cgroup-v2.txt: standardize document format Tejun Heo <tj@kernel.org> - 2017-05-19 17:00 +0200
[PATCH 03/31] btmrvl.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 22/31] futex-requeue-pi.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 08/31] clk.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 07/31] circular-buffers.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 12/31] dcdbas.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 25/31] hw_random.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 21/31] flexible-arrays.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 01/31] bcache.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 04/31] bus-virt-phys-mapping.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 23/31] gcc-plugins.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
Re: [PATCH 23/31] gcc-plugins.txt: standardize document format Kees Cook <keescook@google.com> - 2017-05-24 19:40 +0200
Re: [PATCH 23/31] gcc-plugins.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-24 22:20 +0200
[PATCH 09/31] cpu-load: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 24/31] highuid.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 17/31] DMA-ISA-LPC.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 18/31] debugging-via-ohci1394.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 05/31] cachetlb.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 10/31] cputopology.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 02/31] bt8xxgpio.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 15/31] DMA-API-HOWTO.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 11/31] crc32.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 20/31] eisa.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
[PATCH 14/31] DMA-API.txt: standardize document format Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2017-05-19 03:50 +0200
Page 1 of 2 [1] 2 Next page →
| From | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| Date | 2017-05-19 03:30 +0200 |
| Subject | [PATCH 00/31] Standardize doc formats - part 1 |
| Message-ID | <tIETT-39a-3@gated-at.bofh.it> |
Each document under Documentation/*.txt has its own format. Some follow markup notations, some don't even have a title! In order to try to get some order on it, change the document style to the standard we're adopting after the adoption of ReStructured Text. The documents touched on this series now build fine with Sphinx, if renamed to *.rst extension. The main goal with this is to teach people by example about what format is expected on newer documents. It also helps to add those files to Kernel books. In order to make things more palatable, I'm spliting the conversion into three parts. This is part 1. Mauro Carvalho Chehab (31): bcache.txt: standardize document format bt8xxgpio.txt: standardize document format btmrvl.txt: standardize document format bus-virt-phys-mapping.txt: standardize document format cachetlb.txt: standardize document format cgroup-v2.txt: standardize document format circular-buffers.txt: standardize document format clk.txt: standardize document format cpu-load: standardize document format cputopology.txt: standardize document format crc32.txt: standardize document format dcdbas.txt: standardize document format digsig.txt: standardize document format DMA-API.txt: standardize document format DMA-API-HOWTO.txt: standardize document format DMA-attributes.txt: standardize document format DMA-ISA-LPC.txt: standardize document format debugging-via-ohci1394.txt: standardize document format efi-stub.txt: standardize document format eisa.txt: standardize document format flexible-arrays.txt: standardize document format futex-requeue-pi.txt: standardize document format gcc-plugins.txt: standardize document format highuid.txt: standardize document format hw_random.txt: standardize document format hwspinlock.txt: standardize document format intel_txt.txt: standardize document format Intel-IOMMU.txt: standardize document format io-mapping.txt: standardize document format io_ordering.txt: standardize document format iostats.txt: standardize document format Documentation/DMA-API-HOWTO.txt | 159 +++++---- Documentation/DMA-API.txt | 575 ++++++++++++++++++------------- Documentation/DMA-ISA-LPC.txt | 71 ++-- Documentation/DMA-attributes.txt | 15 +- Documentation/Intel-IOMMU.txt | 36 +- Documentation/bcache.txt | 200 ++++++----- Documentation/bt8xxgpio.txt | 19 +- Documentation/btmrvl.txt | 64 ++-- Documentation/bus-virt-phys-mapping.txt | 63 ++-- Documentation/cachetlb.txt | 92 ++--- Documentation/cgroup-v2.txt | 449 ++++++++++++------------ Documentation/circular-buffers.txt | 51 ++- Documentation/clk.txt | 189 +++++----- Documentation/cpu-load.txt | 117 +++---- Documentation/cputopology.txt | 35 +- Documentation/crc32.txt | 75 ++-- Documentation/dcdbas.txt | 24 +- Documentation/debugging-via-ohci1394.txt | 21 +- Documentation/digsig.txt | 124 +++---- Documentation/efi-stub.txt | 25 +- Documentation/eisa.txt | 260 +++++++------- Documentation/flexible-arrays.txt | 24 +- Documentation/futex-requeue-pi.txt | 83 ++--- Documentation/gcc-plugins.txt | 58 ++-- Documentation/highuid.txt | 46 +-- Documentation/hw_random.txt | 158 +++++---- Documentation/hwspinlock.txt | 527 ++++++++++++++++------------ Documentation/intel_txt.txt | 63 ++-- Documentation/io-mapping.txt | 67 ++-- Documentation/io_ordering.txt | 61 ++-- Documentation/iostats.txt | 40 ++- 31 files changed, 2101 insertions(+), 1690 deletions(-) -- 2.9.4
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| From | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| Date | 2017-05-19 03:30 +0200 |
| Subject | [PATCH 16/31] DMA-attributes.txt: standardize document format |
| Message-ID | <tIETV-39a-51@gated-at.bofh.it> |
| In reply to | #1645017 |
Each text file under Documentation follows a different format. Some doesn't even have titles! Change its representation to follow the adopted standard, using ReST markups for it to be parseable by Sphinx: This file is almost on the standard format. All it needs to be parsed by Sphinx is to fix its main title and add a few blank lines. Yet, it is worth to replace NOTE: by the corresponding ReST markup. While here, remove the extra "---" from a subtitle. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> --- Documentation/DMA-attributes.txt | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/Documentation/DMA-attributes.txt b/Documentation/DMA-attributes.txt index 44c6bc496eee..8f8d97f65d73 100644 --- a/Documentation/DMA-attributes.txt +++ b/Documentation/DMA-attributes.txt @@ -1,5 +1,6 @@ - DMA attributes - ============== +============== +DMA attributes +============== This document describes the semantics of the DMA attributes that are defined in linux/dma-mapping.h. @@ -108,6 +109,7 @@ This is a hint to the DMA-mapping subsystem that it's probably not worth the time to try to allocate memory to in a way that gives better TLB efficiency (AKA it's not worth trying to build the mapping out of larger pages). You might want to specify this if: + - You know that the accesses to this memory won't thrash the TLB. You might know that the accesses are likely to be sequential or that they aren't sequential but it's unlikely you'll ping-pong @@ -121,11 +123,12 @@ pages). You might want to specify this if: the mapping to have a short lifetime then it may be worth it to optimize allocation (avoid coming up with large pages) instead of getting the slight performance win of larger pages. + Setting this hint doesn't guarantee that you won't get huge pages, but it means that we won't try quite as hard to get them. -NOTE: At the moment DMA_ATTR_ALLOC_SINGLE_PAGES is only implemented on ARM, -though ARM64 patches will likely be posted soon. +.. note:: At the moment DMA_ATTR_ALLOC_SINGLE_PAGES is only implemented on ARM, + though ARM64 patches will likely be posted soon. DMA_ATTR_NO_WARN ---------------- @@ -142,10 +145,10 @@ problem at all, depending on the implementation of the retry mechanism. So, this provides a way for drivers to avoid those error messages on calls where allocation failures are not a problem, and shouldn't bother the logs. -NOTE: At the moment DMA_ATTR_NO_WARN is only implemented on PowerPC. +.. note:: At the moment DMA_ATTR_NO_WARN is only implemented on PowerPC. DMA_ATTR_PRIVILEGED ------------------------------- +------------------- Some advanced peripherals such as remote processors and GPUs perform accesses to DMA buffers in both privileged "supervisor" and unprivileged -- 2.9.4
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| From | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| Date | 2017-05-19 03:30 +0200 |
| Subject | [PATCH 27/31] intel_txt.txt: standardize document format |
| Message-ID | <tIETV-39a-53@gated-at.bofh.it> |
| In reply to | #1645017 |
Each text file under Documentation follows a different
format. Some doesn't even have titles!
Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:
- promote main title one level;
- fix the bulleted list markup;
- use bulletted list markup where needed;
- add whitespaces where needed;
- mark literal blocks;
- remove extra ":" after section titles.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
---
Documentation/intel_txt.txt | 63 ++++++++++++++++++++++++++++-----------------
1 file changed, 40 insertions(+), 23 deletions(-)
diff --git a/Documentation/intel_txt.txt b/Documentation/intel_txt.txt
index 91d89c540709..d83c1a2122c9 100644
--- a/Documentation/intel_txt.txt
+++ b/Documentation/intel_txt.txt
@@ -1,4 +1,5 @@
-Intel(R) TXT Overview:
+=====================
+Intel(R) TXT Overview
=====================
Intel's technology for safer computing, Intel(R) Trusted Execution
@@ -8,9 +9,10 @@ provide the building blocks for creating trusted platforms.
Intel TXT was formerly known by the code name LaGrande Technology (LT).
Intel TXT in Brief:
-o Provides dynamic root of trust for measurement (DRTM)
-o Data protection in case of improper shutdown
-o Measurement and verification of launched environment
+
+- Provides dynamic root of trust for measurement (DRTM)
+- Data protection in case of improper shutdown
+- Measurement and verification of launched environment
Intel TXT is part of the vPro(TM) brand and is also available some
non-vPro systems. It is currently available on desktop systems
@@ -24,16 +26,21 @@ which has been updated for the new released platforms.
Intel TXT has been presented at various events over the past few
years, some of which are:
- LinuxTAG 2008:
+
+ - LinuxTAG 2008:
http://www.linuxtag.org/2008/en/conf/events/vp-donnerstag.html
- TRUST2008:
+
+ - TRUST2008:
http://www.trust-conference.eu/downloads/Keynote-Speakers/
3_David-Grawrock_The-Front-Door-of-Trusted-Computing.pdf
- IDF, Shanghai:
+
+ - IDF, Shanghai:
http://www.prcidf.com.cn/index_en.html
- IDFs 2006, 2007 (I'm not sure if/where they are online)
-Trusted Boot Project Overview:
+ - IDFs 2006, 2007
+ (I'm not sure if/where they are online)
+
+Trusted Boot Project Overview
=============================
Trusted Boot (tboot) is an open source, pre-kernel/VMM module that
@@ -87,11 +94,12 @@ Intel-provided firmware).
How Does it Work?
=================
-o Tboot is an executable that is launched by the bootloader as
+- Tboot is an executable that is launched by the bootloader as
the "kernel" (the binary the bootloader executes).
-o It performs all of the work necessary to determine if the
+- It performs all of the work necessary to determine if the
platform supports Intel TXT and, if so, executes the GETSEC[SENTER]
processor instruction that initiates the dynamic root of trust.
+
- If tboot determines that the system does not support Intel TXT
or is not configured correctly (e.g. the SINIT AC Module was
incorrect), it will directly launch the kernel with no changes
@@ -99,12 +107,14 @@ o It performs all of the work necessary to determine if the
- Tboot will output various information about its progress to the
terminal, serial port, and/or an in-memory log; the output
locations can be configured with a command line switch.
-o The GETSEC[SENTER] instruction will return control to tboot and
+
+- The GETSEC[SENTER] instruction will return control to tboot and
tboot then verifies certain aspects of the environment (e.g. TPM NV
lock, e820 table does not have invalid entries, etc.).
-o It will wake the APs from the special sleep state the GETSEC[SENTER]
+- It will wake the APs from the special sleep state the GETSEC[SENTER]
instruction had put them in and place them into a wait-for-SIPI
state.
+
- Because the processors will not respond to an INIT or SIPI when
in the TXT environment, it is necessary to create a small VT-x
guest for the APs. When they run in this guest, they will
@@ -112,8 +122,10 @@ o It will wake the APs from the special sleep state the GETSEC[SENTER]
VMEXITs, and then disable VT and jump to the SIPI vector. This
approach seemed like a better choice than having to insert
special code into the kernel's MP wakeup sequence.
-o Tboot then applies an (optional) user-defined launch policy to
+
+- Tboot then applies an (optional) user-defined launch policy to
verify the kernel and initrd.
+
- This policy is rooted in TPM NV and is described in the tboot
project. The tboot project also contains code for tools to
create and provision the policy.
@@ -121,30 +133,34 @@ o Tboot then applies an (optional) user-defined launch policy to
then any kernel will be launched.
- Policy action is flexible and can include halting on failures
or simply logging them and continuing.
-o Tboot adjusts the e820 table provided by the bootloader to reserve
+
+- Tboot adjusts the e820 table provided by the bootloader to reserve
its own location in memory as well as to reserve certain other
TXT-related regions.
-o As part of its launch, tboot DMA protects all of RAM (using the
+- As part of its launch, tboot DMA protects all of RAM (using the
VT-d PMRs). Thus, the kernel must be booted with 'intel_iommu=on'
in order to remove this blanket protection and use VT-d's
page-level protection.
-o Tboot will populate a shared page with some data about itself and
+- Tboot will populate a shared page with some data about itself and
pass this to the Linux kernel as it transfers control.
+
- The location of the shared page is passed via the boot_params
struct as a physical address.
-o The kernel will look for the tboot shared page address and, if it
+
+- The kernel will look for the tboot shared page address and, if it
exists, map it.
-o As one of the checks/protections provided by TXT, it makes a copy
+- As one of the checks/protections provided by TXT, it makes a copy
of the VT-d DMARs in a DMA-protected region of memory and verifies
them for correctness. The VT-d code will detect if the kernel was
launched with tboot and use this copy instead of the one in the
ACPI table.
-o At this point, tboot and TXT are out of the picture until a
+- At this point, tboot and TXT are out of the picture until a
shutdown (S<n>)
-o In order to put a system into any of the sleep states after a TXT
+- In order to put a system into any of the sleep states after a TXT
launch, TXT must first be exited. This is to prevent attacks that
attempt to crash the system to gain control on reboot and steal
data left in memory.
+
- The kernel will perform all of its sleep preparation and
populate the shared page with the ACPI data needed to put the
platform in the desired sleep state.
@@ -172,7 +188,7 @@ o In order to put a system into any of the sleep states after a TXT
That's pretty much it for TXT support.
-Configuring the System:
+Configuring the System
======================
This code works with 32bit, 32bit PAE, and 64bit (x86_64) kernels.
@@ -181,7 +197,8 @@ In BIOS, the user must enable: TPM, TXT, VT-x, VT-d. Not all BIOSes
allow these to be individually enabled/disabled and the screens in
which to find them are BIOS-specific.
-grub.conf needs to be modified as follows:
+grub.conf needs to be modified as follows::
+
title Linux 2.6.29-tip w/ tboot
root (hd0,0)
kernel /tboot.gz logging=serial,vga,memory
--
2.9.4
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| From | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| Date | 2017-05-19 03:30 +0200 |
| Subject | [PATCH 26/31] hwspinlock.txt: standardize document format |
| Message-ID | <tIETV-39a-45@gated-at.bofh.it> |
| In reply to | #1645017 |
Each text file under Documentation follows a different
format. Some doesn't even have titles!
Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:
- Adjust title markups;
- remove explicit numeration from titles;
- mark literal blocks as such;
- replace _foo_ by **foo** for emphasis;
- adjust whitespaces and add blank lines where needed.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
---
Documentation/hwspinlock.txt | 527 +++++++++++++++++++++++++------------------
1 file changed, 307 insertions(+), 220 deletions(-)
diff --git a/Documentation/hwspinlock.txt b/Documentation/hwspinlock.txt
index 61c1ee98e59f..ed640a278185 100644
--- a/Documentation/hwspinlock.txt
+++ b/Documentation/hwspinlock.txt
@@ -1,6 +1,9 @@
+===========================
Hardware Spinlock Framework
+===========================
-1. Introduction
+Introduction
+============
Hardware spinlock modules provide hardware assistance for synchronization
and mutual exclusion between heterogeneous processors and those not operating
@@ -32,286 +35,370 @@ structure).
A common hwspinlock interface makes it possible to have generic, platform-
independent, drivers.
-2. User API
+User API
+========
+
+::
struct hwspinlock *hwspin_lock_request(void);
- - dynamically assign an hwspinlock and return its address, or NULL
- in case an unused hwspinlock isn't available. Users of this
- API will usually want to communicate the lock's id to the remote core
- before it can be used to achieve synchronization.
- Should be called from a process context (might sleep).
+
+Dynamically assign an hwspinlock and return its address, or NULL
+in case an unused hwspinlock isn't available. Users of this
+API will usually want to communicate the lock's id to the remote core
+before it can be used to achieve synchronization.
+
+Should be called from a process context (might sleep).
+
+::
struct hwspinlock *hwspin_lock_request_specific(unsigned int id);
- - assign a specific hwspinlock id and return its address, or NULL
- if that hwspinlock is already in use. Usually board code will
- be calling this function in order to reserve specific hwspinlock
- ids for predefined purposes.
- Should be called from a process context (might sleep).
+
+Assign a specific hwspinlock id and return its address, or NULL
+if that hwspinlock is already in use. Usually board code will
+be calling this function in order to reserve specific hwspinlock
+ids for predefined purposes.
+
+Should be called from a process context (might sleep).
+
+::
int of_hwspin_lock_get_id(struct device_node *np, int index);
- - retrieve the global lock id for an OF phandle-based specific lock.
- This function provides a means for DT users of a hwspinlock module
- to get the global lock id of a specific hwspinlock, so that it can
- be requested using the normal hwspin_lock_request_specific() API.
- The function returns a lock id number on success, -EPROBE_DEFER if
- the hwspinlock device is not yet registered with the core, or other
- error values.
- Should be called from a process context (might sleep).
+
+Retrieve the global lock id for an OF phandle-based specific lock.
+This function provides a means for DT users of a hwspinlock module
+to get the global lock id of a specific hwspinlock, so that it can
+be requested using the normal hwspin_lock_request_specific() API.
+
+The function returns a lock id number on success, -EPROBE_DEFER if
+the hwspinlock device is not yet registered with the core, or other
+error values.
+
+Should be called from a process context (might sleep).
+
+::
int hwspin_lock_free(struct hwspinlock *hwlock);
- - free a previously-assigned hwspinlock; returns 0 on success, or an
- appropriate error code on failure (e.g. -EINVAL if the hwspinlock
- is already free).
- Should be called from a process context (might sleep).
+
+Free a previously-assigned hwspinlock; returns 0 on success, or an
+appropriate error code on failure (e.g. -EINVAL if the hwspinlock
+is already free).
+
+Should be called from a process context (might sleep).
+
+::
int hwspin_lock_timeout(struct hwspinlock *hwlock, unsigned int timeout);
- - lock a previously-assigned hwspinlock with a timeout limit (specified in
- msecs). If the hwspinlock is already taken, the function will busy loop
- waiting for it to be released, but give up when the timeout elapses.
- Upon a successful return from this function, preemption is disabled so
- the caller must not sleep, and is advised to release the hwspinlock as
- soon as possible, in order to minimize remote cores polling on the
- hardware interconnect.
- Returns 0 when successful and an appropriate error code otherwise (most
- notably -ETIMEDOUT if the hwspinlock is still busy after timeout msecs).
- The function will never sleep.
+
+Lock a previously-assigned hwspinlock with a timeout limit (specified in
+msecs). If the hwspinlock is already taken, the function will busy loop
+waiting for it to be released, but give up when the timeout elapses.
+Upon a successful return from this function, preemption is disabled so
+the caller must not sleep, and is advised to release the hwspinlock as
+soon as possible, in order to minimize remote cores polling on the
+hardware interconnect.
+
+Returns 0 when successful and an appropriate error code otherwise (most
+notably -ETIMEDOUT if the hwspinlock is still busy after timeout msecs).
+The function will never sleep.
+
+::
int hwspin_lock_timeout_irq(struct hwspinlock *hwlock, unsigned int timeout);
- - lock a previously-assigned hwspinlock with a timeout limit (specified in
- msecs). If the hwspinlock is already taken, the function will busy loop
- waiting for it to be released, but give up when the timeout elapses.
- Upon a successful return from this function, preemption and the local
- interrupts are disabled, so the caller must not sleep, and is advised to
- release the hwspinlock as soon as possible.
- Returns 0 when successful and an appropriate error code otherwise (most
- notably -ETIMEDOUT if the hwspinlock is still busy after timeout msecs).
- The function will never sleep.
+
+Lock a previously-assigned hwspinlock with a timeout limit (specified in
+msecs). If the hwspinlock is already taken, the function will busy loop
+waiting for it to be released, but give up when the timeout elapses.
+Upon a successful return from this function, preemption and the local
+interrupts are disabled, so the caller must not sleep, and is advised to
+release the hwspinlock as soon as possible.
+
+Returns 0 when successful and an appropriate error code otherwise (most
+notably -ETIMEDOUT if the hwspinlock is still busy after timeout msecs).
+The function will never sleep.
+
+::
int hwspin_lock_timeout_irqsave(struct hwspinlock *hwlock, unsigned int to,
- unsigned long *flags);
- - lock a previously-assigned hwspinlock with a timeout limit (specified in
- msecs). If the hwspinlock is already taken, the function will busy loop
- waiting for it to be released, but give up when the timeout elapses.
- Upon a successful return from this function, preemption is disabled,
- local interrupts are disabled and their previous state is saved at the
- given flags placeholder. The caller must not sleep, and is advised to
- release the hwspinlock as soon as possible.
- Returns 0 when successful and an appropriate error code otherwise (most
- notably -ETIMEDOUT if the hwspinlock is still busy after timeout msecs).
- The function will never sleep.
+ unsigned long *flags);
+
+Lock a previously-assigned hwspinlock with a timeout limit (specified in
+msecs). If the hwspinlock is already taken, the function will busy loop
+waiting for it to be released, but give up when the timeout elapses.
+Upon a successful return from this function, preemption is disabled,
+local interrupts are disabled and their previous state is saved at the
+given flags placeholder. The caller must not sleep, and is advised to
+release the hwspinlock as soon as possible.
+
+Returns 0 when successful and an appropriate error code otherwise (most
+notably -ETIMEDOUT if the hwspinlock is still busy after timeout msecs).
+
+The function will never sleep.
+
+::
int hwspin_trylock(struct hwspinlock *hwlock);
- - attempt to lock a previously-assigned hwspinlock, but immediately fail if
- it is already taken.
- Upon a successful return from this function, preemption is disabled so
- caller must not sleep, and is advised to release the hwspinlock as soon as
- possible, in order to minimize remote cores polling on the hardware
- interconnect.
- Returns 0 on success and an appropriate error code otherwise (most
- notably -EBUSY if the hwspinlock was already taken).
- The function will never sleep.
+
+
+Attempt to lock a previously-assigned hwspinlock, but immediately fail if
+it is already taken.
+
+Upon a successful return from this function, preemption is disabled so
+caller must not sleep, and is advised to release the hwspinlock as soon as
+possible, in order to minimize remote cores polling on the hardware
+interconnect.
+
+Returns 0 on success and an appropriate error code otherwise (most
+notably -EBUSY if the hwspinlock was already taken).
+The function will never sleep.
+
+::
int hwspin_trylock_irq(struct hwspinlock *hwlock);
- - attempt to lock a previously-assigned hwspinlock, but immediately fail if
- it is already taken.
- Upon a successful return from this function, preemption and the local
- interrupts are disabled so caller must not sleep, and is advised to
- release the hwspinlock as soon as possible.
- Returns 0 on success and an appropriate error code otherwise (most
- notably -EBUSY if the hwspinlock was already taken).
- The function will never sleep.
+
+
+Attempt to lock a previously-assigned hwspinlock, but immediately fail if
+it is already taken.
+
+Upon a successful return from this function, preemption and the local
+interrupts are disabled so caller must not sleep, and is advised to
+release the hwspinlock as soon as possible.
+
+Returns 0 on success and an appropriate error code otherwise (most
+notably -EBUSY if the hwspinlock was already taken).
+
+The function will never sleep.
+
+::
int hwspin_trylock_irqsave(struct hwspinlock *hwlock, unsigned long *flags);
- - attempt to lock a previously-assigned hwspinlock, but immediately fail if
- it is already taken.
- Upon a successful return from this function, preemption is disabled,
- the local interrupts are disabled and their previous state is saved
- at the given flags placeholder. The caller must not sleep, and is advised
- to release the hwspinlock as soon as possible.
- Returns 0 on success and an appropriate error code otherwise (most
- notably -EBUSY if the hwspinlock was already taken).
- The function will never sleep.
+
+Attempt to lock a previously-assigned hwspinlock, but immediately fail if
+it is already taken.
+
+Upon a successful return from this function, preemption is disabled,
+the local interrupts are disabled and their previous state is saved
+at the given flags placeholder. The caller must not sleep, and is advised
+to release the hwspinlock as soon as possible.
+
+Returns 0 on success and an appropriate error code otherwise (most
+notably -EBUSY if the hwspinlock was already taken).
+The function will never sleep.
+
+::
void hwspin_unlock(struct hwspinlock *hwlock);
- - unlock a previously-locked hwspinlock. Always succeed, and can be called
- from any context (the function never sleeps). Note: code should _never_
- unlock an hwspinlock which is already unlocked (there is no protection
- against this).
+
+Unlock a previously-locked hwspinlock. Always succeed, and can be called
+from any context (the function never sleeps).
+
+.. note::
+
+ code should **never** unlock an hwspinlock which is already unlocked
+ (there is no protection against this).
+
+::
void hwspin_unlock_irq(struct hwspinlock *hwlock);
- - unlock a previously-locked hwspinlock and enable local interrupts.
- The caller should _never_ unlock an hwspinlock which is already unlocked.
- Doing so is considered a bug (there is no protection against this).
- Upon a successful return from this function, preemption and local
- interrupts are enabled. This function will never sleep.
+
+Unlock a previously-locked hwspinlock and enable local interrupts.
+The caller should **never** unlock an hwspinlock which is already unlocked.
+
+Doing so is considered a bug (there is no protection against this).
+Upon a successful return from this function, preemption and local
+interrupts are enabled. This function will never sleep.
+
+::
void
hwspin_unlock_irqrestore(struct hwspinlock *hwlock, unsigned long *flags);
- - unlock a previously-locked hwspinlock.
- The caller should _never_ unlock an hwspinlock which is already unlocked.
- Doing so is considered a bug (there is no protection against this).
- Upon a successful return from this function, preemption is reenabled,
- and the state of the local interrupts is restored to the state saved at
- the given flags. This function will never sleep.
+
+Unlock a previously-locked hwspinlock.
+
+The caller should **never** unlock an hwspinlock which is already unlocked.
+Doing so is considered a bug (there is no protection against this).
+Upon a successful return from this function, preemption is reenabled,
+and the state of the local interrupts is restored to the state saved at
+the given flags. This function will never sleep.
+
+::
int hwspin_lock_get_id(struct hwspinlock *hwlock);
- - retrieve id number of a given hwspinlock. This is needed when an
- hwspinlock is dynamically assigned: before it can be used to achieve
- mutual exclusion with a remote cpu, the id number should be communicated
- to the remote task with which we want to synchronize.
- Returns the hwspinlock id number, or -EINVAL if hwlock is null.
-
-3. Typical usage
-
-#include <linux/hwspinlock.h>
-#include <linux/err.h>
-
-int hwspinlock_example1(void)
-{
- struct hwspinlock *hwlock;
- int ret;
-
- /* dynamically assign a hwspinlock */
- hwlock = hwspin_lock_request();
- if (!hwlock)
- ...
-
- id = hwspin_lock_get_id(hwlock);
- /* probably need to communicate id to a remote processor now */
-
- /* take the lock, spin for 1 sec if it's already taken */
- ret = hwspin_lock_timeout(hwlock, 1000);
- if (ret)
- ...
-
- /*
- * we took the lock, do our thing now, but do NOT sleep
- */
-
- /* release the lock */
- hwspin_unlock(hwlock);
-
- /* free the lock */
- ret = hwspin_lock_free(hwlock);
- if (ret)
- ...
-
- return ret;
-}
-
-int hwspinlock_example2(void)
-{
- struct hwspinlock *hwlock;
- int ret;
-
- /*
- * assign a specific hwspinlock id - this should be called early
- * by board init code.
- */
- hwlock = hwspin_lock_request_specific(PREDEFINED_LOCK_ID);
- if (!hwlock)
- ...
-
- /* try to take it, but don't spin on it */
- ret = hwspin_trylock(hwlock);
- if (!ret) {
- pr_info("lock is already taken\n");
- return -EBUSY;
- }
- /*
- * we took the lock, do our thing now, but do NOT sleep
- */
+Retrieve id number of a given hwspinlock. This is needed when an
+hwspinlock is dynamically assigned: before it can be used to achieve
+mutual exclusion with a remote cpu, the id number should be communicated
+to the remote task with which we want to synchronize.
+
+Returns the hwspinlock id number, or -EINVAL if hwlock is null.
+
+Typical usage
+=============
+
+::
+
+ #include <linux/hwspinlock.h>
+ #include <linux/err.h>
+
+ int hwspinlock_example1(void)
+ {
+ struct hwspinlock *hwlock;
+ int ret;
+
+ /* dynamically assign a hwspinlock */
+ hwlock = hwspin_lock_request();
+ if (!hwlock)
+ ...
- /* release the lock */
- hwspin_unlock(hwlock);
+ id = hwspin_lock_get_id(hwlock);
+ /* probably need to communicate id to a remote processor now */
- /* free the lock */
- ret = hwspin_lock_free(hwlock);
- if (ret)
- ...
+ /* take the lock, spin for 1 sec if it's already taken */
+ ret = hwspin_lock_timeout(hwlock, 1000);
+ if (ret)
+ ...
+
+ /*
+ * we took the lock, do our thing now, but do NOT sleep
+ */
+
+ /* release the lock */
+ hwspin_unlock(hwlock);
+
+ /* free the lock */
+ ret = hwspin_lock_free(hwlock);
+ if (ret)
+ ...
+
+ return ret;
+ }
+
+ int hwspinlock_example2(void)
+ {
+ struct hwspinlock *hwlock;
+ int ret;
+
+ /*
+ * assign a specific hwspinlock id - this should be called early
+ * by board init code.
+ */
+ hwlock = hwspin_lock_request_specific(PREDEFINED_LOCK_ID);
+ if (!hwlock)
+ ...
+
+ /* try to take it, but don't spin on it */
+ ret = hwspin_trylock(hwlock);
+ if (!ret) {
+ pr_info("lock is already taken\n");
+ return -EBUSY;
+ }
+
+ /*
+ * we took the lock, do our thing now, but do NOT sleep
+ */
+
+ /* release the lock */
+ hwspin_unlock(hwlock);
+
+ /* free the lock */
+ ret = hwspin_lock_free(hwlock);
+ if (ret)
+ ...
+
+ return ret;
+ }
- return ret;
-}
+API for implementors
+====================
-4. API for implementors
+::
int hwspin_lock_register(struct hwspinlock_device *bank, struct device *dev,
const struct hwspinlock_ops *ops, int base_id, int num_locks);
- - to be called from the underlying platform-specific implementation, in
- order to register a new hwspinlock device (which is usually a bank of
- numerous locks). Should be called from a process context (this function
- might sleep).
- Returns 0 on success, or appropriate error code on failure.
+
+To be called from the underlying platform-specific implementation, in
+order to register a new hwspinlock device (which is usually a bank of
+numerous locks). Should be called from a process context (this function
+might sleep).
+
+Returns 0 on success, or appropriate error code on failure.
+
+::
int hwspin_lock_unregister(struct hwspinlock_device *bank);
- - to be called from the underlying vendor-specific implementation, in order
- to unregister an hwspinlock device (which is usually a bank of numerous
- locks).
- Should be called from a process context (this function might sleep).
- Returns the address of hwspinlock on success, or NULL on error (e.g.
- if the hwspinlock is still in use).
-
-5. Important structs
+
+To be called from the underlying vendor-specific implementation, in order
+to unregister an hwspinlock device (which is usually a bank of numerous
+locks).
+
+Should be called from a process context (this function might sleep).
+
+Returns the address of hwspinlock on success, or NULL on error (e.g.
+if the hwspinlock is still in use).
+
+Important structs
+=================
struct hwspinlock_device is a device which usually contains a bank
of hardware locks. It is registered by the underlying hwspinlock
implementation using the hwspin_lock_register() API.
-/**
- * struct hwspinlock_device - a device which usually spans numerous hwspinlocks
- * @dev: underlying device, will be used to invoke runtime PM api
- * @ops: platform-specific hwspinlock handlers
- * @base_id: id index of the first lock in this device
- * @num_locks: number of locks in this device
- * @lock: dynamically allocated array of 'struct hwspinlock'
- */
-struct hwspinlock_device {
- struct device *dev;
- const struct hwspinlock_ops *ops;
- int base_id;
- int num_locks;
- struct hwspinlock lock[0];
-};
+::
+
+ /**
+ * struct hwspinlock_device - a device which usually spans numerous hwspinlocks
+ * @dev: underlying device, will be used to invoke runtime PM api
+ * @ops: platform-specific hwspinlock handlers
+ * @base_id: id index of the first lock in this device
+ * @num_locks: number of locks in this device
+ * @lock: dynamically allocated array of 'struct hwspinlock'
+ */
+ struct hwspinlock_device {
+ struct device *dev;
+ const struct hwspinlock_ops *ops;
+ int base_id;
+ int num_locks;
+ struct hwspinlock lock[0];
+ };
struct hwspinlock_device contains an array of hwspinlock structs, each
-of which represents a single hardware lock:
+of which represents a single hardware lock::
-/**
- * struct hwspinlock - this struct represents a single hwspinlock instance
- * @bank: the hwspinlock_device structure which owns this lock
- * @lock: initialized and used by hwspinlock core
- * @priv: private data, owned by the underlying platform-specific hwspinlock drv
- */
-struct hwspinlock {
- struct hwspinlock_device *bank;
- spinlock_t lock;
- void *priv;
-};
+ /**
+ * struct hwspinlock - this struct represents a single hwspinlock instance
+ * @bank: the hwspinlock_device structure which owns this lock
+ * @lock: initialized and used by hwspinlock core
+ * @priv: private data, owned by the underlying platform-specific hwspinlock drv
+ */
+ struct hwspinlock {
+ struct hwspinlock_device *bank;
+ spinlock_t lock;
+ void *priv;
+ };
When registering a bank of locks, the hwspinlock driver only needs to
set the priv members of the locks. The rest of the members are set and
initialized by the hwspinlock core itself.
-6. Implementation callbacks
+Implementation callbacks
+========================
-There are three possible callbacks defined in 'struct hwspinlock_ops':
+There are three possible callbacks defined in 'struct hwspinlock_ops'::
-struct hwspinlock_ops {
- int (*trylock)(struct hwspinlock *lock);
- void (*unlock)(struct hwspinlock *lock);
- void (*relax)(struct hwspinlock *lock);
-};
+ struct hwspinlock_ops {
+ int (*trylock)(struct hwspinlock *lock);
+ void (*unlock)(struct hwspinlock *lock);
+ void (*relax)(struct hwspinlock *lock);
+ };
The first two callbacks are mandatory:
The ->trylock() callback should make a single attempt to take the lock, and
-return 0 on failure and 1 on success. This callback may _not_ sleep.
+return 0 on failure and 1 on success. This callback may **not** sleep.
The ->unlock() callback releases the lock. It always succeed, and it, too,
-may _not_ sleep.
+may **not** sleep.
The ->relax() callback is optional. It is called by hwspinlock core while
spinning on a lock, and can be used by the underlying implementation to force
-a delay between two successive invocations of ->trylock(). It may _not_ sleep.
+a delay between two successive invocations of ->trylock(). It may **not** sleep.
--
2.9.4
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| From | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| Date | 2017-05-19 03:30 +0200 |
| Subject | [PATCH 13/31] digsig.txt: standardize document format |
| Message-ID | <tIETW-39a-75@gated-at.bofh.it> |
| In reply to | #1645017 |
Each text file under Documentation follows a different
format. Some doesn't even have titles!
Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:
- comment the internal index;
- use the proper markups for titles;
- mark literal blocks.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
---
Documentation/digsig.txt | 124 ++++++++++++++++++++++++-----------------------
1 file changed, 64 insertions(+), 60 deletions(-)
diff --git a/Documentation/digsig.txt b/Documentation/digsig.txt
index 3f682889068b..7ce23eddee37 100644
--- a/Documentation/digsig.txt
+++ b/Documentation/digsig.txt
@@ -1,13 +1,19 @@
Digital Signature Verification API
+----------------------------------
-CONTENTS
+:Author: Dmitry Kasatkin
+:Date: 06.10.2011
-1. Introduction
-2. API
-3. User-space utilities
+.. CONTENTS
-1. Introduction
+ 1. Introduction
+ 2. API
+ 3. User-space utilities
+
+
+Introduction
+============
Digital signature verification API provides a method to verify digital signature.
Currently digital signatures are used by the IMA/EVM integrity protection subsystem.
@@ -17,25 +23,25 @@ GnuPG multi-precision integers (MPI) library. The kernel port provides
memory allocation errors handling, has been refactored according to kernel
coding style, and checkpatch.pl reported errors and warnings have been fixed.
-Public key and signature consist of header and MPIs.
+Public key and signature consist of header and MPIs::
-struct pubkey_hdr {
- uint8_t version; /* key format version */
- time_t timestamp; /* key made, always 0 for now */
- uint8_t algo;
- uint8_t nmpi;
- char mpi[0];
-} __packed;
+ struct pubkey_hdr {
+ uint8_t version; /* key format version */
+ time_t timestamp; /* key made, always 0 for now */
+ uint8_t algo;
+ uint8_t nmpi;
+ char mpi[0];
+ } __packed;
-struct signature_hdr {
- uint8_t version; /* signature format version */
- time_t timestamp; /* signature made */
- uint8_t algo;
- uint8_t hash;
- uint8_t keyid[8];
- uint8_t nmpi;
- char mpi[0];
-} __packed;
+ struct signature_hdr {
+ uint8_t version; /* signature format version */
+ time_t timestamp; /* signature made */
+ uint8_t algo;
+ uint8_t hash;
+ uint8_t keyid[8];
+ uint8_t nmpi;
+ char mpi[0];
+ } __packed;
keyid equals to SHA1[12-19] over the total key content.
Signature header is used as an input to generate a signature.
@@ -43,31 +49,33 @@ Such approach insures that key or signature header could not be changed.
It protects timestamp from been changed and can be used for rollback
protection.
-2. API
+API
+===
-API currently includes only 1 function:
+API currently includes only 1 function::
digsig_verify() - digital signature verification with public key
-/**
- * digsig_verify() - digital signature verification with public key
- * @keyring: keyring to search key in
- * @sig: digital signature
- * @sigen: length of the signature
- * @data: data
- * @datalen: length of the data
- * @return: 0 on success, -EINVAL otherwise
- *
- * Verifies data integrity against digital signature.
- * Currently only RSA is supported.
- * Normally hash of the content is used as a data for this function.
- *
- */
-int digsig_verify(struct key *keyring, const char *sig, int siglen,
- const char *data, int datalen);
+ /**
+ * digsig_verify() - digital signature verification with public key
+ * @keyring: keyring to search key in
+ * @sig: digital signature
+ * @sigen: length of the signature
+ * @data: data
+ * @datalen: length of the data
+ * @return: 0 on success, -EINVAL otherwise
+ *
+ * Verifies data integrity against digital signature.
+ * Currently only RSA is supported.
+ * Normally hash of the content is used as a data for this function.
+ *
+ */
+ int digsig_verify(struct key *keyring, const char *sig, int siglen,
+ const char *data, int datalen);
-3. User-space utilities
+User-space utilities
+====================
The signing and key management utilities evm-utils provide functionality
to generate signatures, to load keys into the kernel keyring.
@@ -75,22 +83,18 @@ Keys can be in PEM or converted to the kernel format.
When the key is added to the kernel keyring, the keyid defines the name
of the key: 5D2B05FC633EE3E8 in the example bellow.
-Here is example output of the keyctl utility.
-
-$ keyctl show
-Session Keyring
- -3 --alswrv 0 0 keyring: _ses
-603976250 --alswrv 0 -1 \_ keyring: _uid.0
-817777377 --alswrv 0 0 \_ user: kmk
-891974900 --alswrv 0 0 \_ encrypted: evm-key
-170323636 --alswrv 0 0 \_ keyring: _module
-548221616 --alswrv 0 0 \_ keyring: _ima
-128198054 --alswrv 0 0 \_ keyring: _evm
-
-$ keyctl list 128198054
-1 key in keyring:
-620789745: --alswrv 0 0 user: 5D2B05FC633EE3E8
-
-
-Dmitry Kasatkin
-06.10.2011
+Here is example output of the keyctl utility::
+
+ $ keyctl show
+ Session Keyring
+ -3 --alswrv 0 0 keyring: _ses
+ 603976250 --alswrv 0 -1 \_ keyring: _uid.0
+ 817777377 --alswrv 0 0 \_ user: kmk
+ 891974900 --alswrv 0 0 \_ encrypted: evm-key
+ 170323636 --alswrv 0 0 \_ keyring: _module
+ 548221616 --alswrv 0 0 \_ keyring: _ima
+ 128198054 --alswrv 0 0 \_ keyring: _evm
+
+ $ keyctl list 128198054
+ 1 key in keyring:
+ 620789745: --alswrv 0 0 user: 5D2B05FC633EE3E8
--
2.9.4
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| From | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| Date | 2017-05-19 03:50 +0200 |
| Subject | [PATCH 19/31] efi-stub.txt: standardize document format |
| Message-ID | <tIFdf-3gE-1@gated-at.bofh.it> |
| In reply to | #1645017 |
Each text file under Documentation follows a different format. Some doesn't even have titles! Change its representation to follow the adopted standard, using ReST markups for it to be parseable by Sphinx: - use proper markups for titles; - identify literal blocks. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> --- Documentation/efi-stub.txt | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) diff --git a/Documentation/efi-stub.txt b/Documentation/efi-stub.txt index e15746988261..41df801f9a50 100644 --- a/Documentation/efi-stub.txt +++ b/Documentation/efi-stub.txt @@ -1,5 +1,6 @@ - The EFI Boot Stub - --------------------------- +================= +The EFI Boot Stub +================= On the x86 and ARM platforms, a kernel zImage/bzImage can masquerade as a PE/COFF image, thereby convincing EFI firmware loaders to load @@ -25,7 +26,8 @@ a certain sense it *IS* the boot loader. The EFI boot stub is enabled with the CONFIG_EFI_STUB kernel option. -**** How to install bzImage.efi +How to install bzImage.efi +-------------------------- The bzImage located in arch/x86/boot/bzImage must be copied to the EFI System Partition (ESP) and renamed with the extension ".efi". Without @@ -37,14 +39,16 @@ may not need to be renamed. Similarly for arm64, arch/arm64/boot/Image should be copied but not necessarily renamed. -**** Passing kernel parameters from the EFI shell +Passing kernel parameters from the EFI shell +-------------------------------------------- -Arguments to the kernel can be passed after bzImage.efi, e.g. +Arguments to the kernel can be passed after bzImage.efi, e.g.:: fs0:> bzImage.efi console=ttyS0 root=/dev/sda4 -**** The "initrd=" option +The "initrd=" option +-------------------- Like most boot loaders, the EFI stub allows the user to specify multiple initrd files using the "initrd=" option. This is the only EFI @@ -54,9 +58,9 @@ kernel when it boots. The path to the initrd file must be an absolute path from the beginning of the ESP, relative path names do not work. Also, the path is an EFI-style path and directory elements must be separated with -backslashes (\). For example, given the following directory layout, +backslashes (\). For example, given the following directory layout:: -fs0:> + fs0:> Kernels\ bzImage.efi initrd-large.img @@ -66,7 +70,7 @@ fs0:> initrd-medium.img to boot with the initrd-large.img file if the current working -directory is fs0:\Kernels, the following command must be used, +directory is fs0:\Kernels, the following command must be used:: fs0:\Kernels> bzImage.efi initrd=\Kernels\initrd-large.img @@ -76,7 +80,8 @@ which understands relative paths, whereas the rest of the command line is passed to bzImage.efi. -**** The "dtb=" option +The "dtb=" option +----------------- For the ARM and arm64 architectures, we also need to be able to provide a device tree to the kernel. This is done with the "dtb=" command line option, -- 2.9.4
[toc] | [prev] | [next] | [standalone]
| From | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| Date | 2017-05-19 03:50 +0200 |
| Subject | [PATCH 28/31] Intel-IOMMU.txt: standardize document format |
| Message-ID | <tIFdg-3gE-7@gated-at.bofh.it> |
| In reply to | #1645017 |
Each text file under Documentation follows a different format. Some doesn't even have titles! Change its representation to follow the adopted standard, using ReST markups for it to be parseable by Sphinx: This file is almost in the right format. It only needed to convert a list to bulleted list and to use the right markup for literal blocks. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> --- Documentation/Intel-IOMMU.txt | 36 +++++++++++++++++++----------------- 1 file changed, 19 insertions(+), 17 deletions(-) diff --git a/Documentation/Intel-IOMMU.txt b/Documentation/Intel-IOMMU.txt index 49585b6e1ea2..11151bd39b2f 100644 --- a/Documentation/Intel-IOMMU.txt +++ b/Documentation/Intel-IOMMU.txt @@ -9,11 +9,11 @@ This guide gives a quick cheat sheet for some basic understanding. Some Keywords -DMAR - DMA remapping -DRHD - DMA Remapping Hardware Unit Definition -RMRR - Reserved memory Region Reporting Structure -ZLR - Zero length reads from PCI devices -IOVA - IO Virtual address. +- DMAR - DMA remapping +- DRHD - DMA Remapping Hardware Unit Definition +- RMRR - Reserved memory Region Reporting Structure +- ZLR - Zero length reads from PCI devices +- IOVA - IO Virtual address. Basic stuff ----------- @@ -33,7 +33,7 @@ devices that need to access these regions. OS is expected to setup unity mappings for these regions for these devices to access these regions. How is IOVA generated? ---------------------- +---------------------- Well behaved drivers call pci_map_*() calls before sending command to device that needs to perform DMA. Once DMA is completed and mapping is no longer @@ -82,14 +82,14 @@ in ACPI. ACPI: DMAR (v001 A M I OEMDMAR 0x00000001 MSFT 0x00000097) @ 0x000000007f5b5ef0 When DMAR is being processed and initialized by ACPI, prints DMAR locations -and any RMRR's processed. +and any RMRR's processed:: -ACPI DMAR:Host address width 36 -ACPI DMAR:DRHD (flags: 0x00000000)base: 0x00000000fed90000 -ACPI DMAR:DRHD (flags: 0x00000000)base: 0x00000000fed91000 -ACPI DMAR:DRHD (flags: 0x00000001)base: 0x00000000fed93000 -ACPI DMAR:RMRR base: 0x00000000000ed000 end: 0x00000000000effff -ACPI DMAR:RMRR base: 0x000000007f600000 end: 0x000000007fffffff + ACPI DMAR:Host address width 36 + ACPI DMAR:DRHD (flags: 0x00000000)base: 0x00000000fed90000 + ACPI DMAR:DRHD (flags: 0x00000000)base: 0x00000000fed91000 + ACPI DMAR:DRHD (flags: 0x00000001)base: 0x00000000fed93000 + ACPI DMAR:RMRR base: 0x00000000000ed000 end: 0x00000000000effff + ACPI DMAR:RMRR base: 0x000000007f600000 end: 0x000000007fffffff When DMAR is enabled for use, you will notice.. @@ -98,10 +98,12 @@ PCI-DMA: Using DMAR IOMMU Fault reporting --------------- -DMAR:[DMA Write] Request device [00:02.0] fault addr 6df084000 -DMAR:[fault reason 05] PTE Write access is not set -DMAR:[DMA Write] Request device [00:02.0] fault addr 6df084000 -DMAR:[fault reason 05] PTE Write access is not set +:: + + DMAR:[DMA Write] Request device [00:02.0] fault addr 6df084000 + DMAR:[fault reason 05] PTE Write access is not set + DMAR:[DMA Write] Request device [00:02.0] fault addr 6df084000 + DMAR:[fault reason 05] PTE Write access is not set TBD ---- -- 2.9.4
[toc] | [prev] | [next] | [standalone]
| From | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| Date | 2017-05-19 03:50 +0200 |
| Subject | [PATCH 06/31] cgroup-v2.txt: standardize document format |
| Message-ID | <tIFdf-3gE-3@gated-at.bofh.it> |
| In reply to | #1645017 |
Each text file under Documentation follows a different
format. Some doesn't even have titles!
Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:
- Comment the internal index;
- Use :Date: and :Author: for authorship;
- Mark titles;
- Mark literal blocks;
- Adjust witespaces;
- Mark notes;
- Use table notation for the existing tables.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
---
Documentation/cgroup-v2.txt | 449 +++++++++++++++++++++++---------------------
1 file changed, 234 insertions(+), 215 deletions(-)
diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt
index dc5e2dcdbef4..491dd0200395 100644
--- a/Documentation/cgroup-v2.txt
+++ b/Documentation/cgroup-v2.txt
@@ -1,7 +1,9 @@
-
+================
Control Group v2
+================
-October, 2015 Tejun Heo <tj@kernel.org>
+:Date: October, 2015
+:Author: Tejun Heo <tj@kernel.org>
This is the authoritative documentation on the design, interface and
conventions of cgroup v2. It describes all userland-visible aspects
@@ -9,70 +11,72 @@ of cgroup including core and specific controller behaviors. All
future changes must be reflected in this document. Documentation for
v1 is available under Documentation/cgroup-v1/.
-CONTENTS
+.. CONTENTS
-1. Introduction
- 1-1. Terminology
- 1-2. What is cgroup?
-2. Basic Operations
- 2-1. Mounting
- 2-2. Organizing Processes
- 2-3. [Un]populated Notification
- 2-4. Controlling Controllers
- 2-4-1. Enabling and Disabling
- 2-4-2. Top-down Constraint
- 2-4-3. No Internal Process Constraint
- 2-5. Delegation
- 2-5-1. Model of Delegation
- 2-5-2. Delegation Containment
- 2-6. Guidelines
- 2-6-1. Organize Once and Control
- 2-6-2. Avoid Name Collisions
-3. Resource Distribution Models
- 3-1. Weights
- 3-2. Limits
- 3-3. Protections
- 3-4. Allocations
-4. Interface Files
- 4-1. Format
- 4-2. Conventions
- 4-3. Core Interface Files
-5. Controllers
- 5-1. CPU
- 5-1-1. CPU Interface Files
- 5-2. Memory
- 5-2-1. Memory Interface Files
- 5-2-2. Usage Guidelines
- 5-2-3. Memory Ownership
- 5-3. IO
- 5-3-1. IO Interface Files
- 5-3-2. Writeback
- 5-4. PID
- 5-4-1. PID Interface Files
- 5-5. RDMA
- 5-5-1. RDMA Interface Files
- 5-6. Misc
- 5-6-1. perf_event
-6. Namespace
- 6-1. Basics
- 6-2. The Root and Views
- 6-3. Migration and setns(2)
- 6-4. Interaction with Other Namespaces
-P. Information on Kernel Programming
- P-1. Filesystem Support for Writeback
-D. Deprecated v1 Core Features
-R. Issues with v1 and Rationales for v2
- R-1. Multiple Hierarchies
- R-2. Thread Granularity
- R-3. Competition Between Inner Nodes and Threads
- R-4. Other Interface Issues
- R-5. Controller Issues and Remedies
- R-5-1. Memory
+ 1. Introduction
+ 1-1. Terminology
+ 1-2. What is cgroup?
+ 2. Basic Operations
+ 2-1. Mounting
+ 2-2. Organizing Processes
+ 2-3. [Un]populated Notification
+ 2-4. Controlling Controllers
+ 2-4-1. Enabling and Disabling
+ 2-4-2. Top-down Constraint
+ 2-4-3. No Internal Process Constraint
+ 2-5. Delegation
+ 2-5-1. Model of Delegation
+ 2-5-2. Delegation Containment
+ 2-6. Guidelines
+ 2-6-1. Organize Once and Control
+ 2-6-2. Avoid Name Collisions
+ 3. Resource Distribution Models
+ 3-1. Weights
+ 3-2. Limits
+ 3-3. Protections
+ 3-4. Allocations
+ 4. Interface Files
+ 4-1. Format
+ 4-2. Conventions
+ 4-3. Core Interface Files
+ 5. Controllers
+ 5-1. CPU
+ 5-1-1. CPU Interface Files
+ 5-2. Memory
+ 5-2-1. Memory Interface Files
+ 5-2-2. Usage Guidelines
+ 5-2-3. Memory Ownership
+ 5-3. IO
+ 5-3-1. IO Interface Files
+ 5-3-2. Writeback
+ 5-4. PID
+ 5-4-1. PID Interface Files
+ 5-5. RDMA
+ 5-5-1. RDMA Interface Files
+ 5-6. Misc
+ 5-6-1. perf_event
+ 6. Namespace
+ 6-1. Basics
+ 6-2. The Root and Views
+ 6-3. Migration and setns(2)
+ 6-4. Interaction with Other Namespaces
+ P. Information on Kernel Programming
+ P-1. Filesystem Support for Writeback
+ D. Deprecated v1 Core Features
+ R. Issues with v1 and Rationales for v2
+ R-1. Multiple Hierarchies
+ R-2. Thread Granularity
+ R-3. Competition Between Inner Nodes and Threads
+ R-4. Other Interface Issues
+ R-5. Controller Issues and Remedies
+ R-5-1. Memory
-1. Introduction
+Introduction
+============
-1-1. Terminology
+Terminology
+-----------
"cgroup" stands for "control group" and is never capitalized. The
singular form is used to designate the whole feature and also as a
@@ -80,7 +84,8 @@ qualifier as in "cgroup controllers". When explicitly referring to
multiple individual control groups, the plural form "cgroups" is used.
-1-2. What is cgroup?
+What is cgroup?
+---------------
cgroup is a mechanism to organize processes hierarchically and
distribute system resources along the hierarchy in a controlled and
@@ -110,12 +115,14 @@ restrictions set closer to the root in the hierarchy can not be
overridden from further away.
-2. Basic Operations
+Basic Operations
+================
-2-1. Mounting
+Mounting
+--------
Unlike v1, cgroup v2 has only single hierarchy. The cgroup v2
-hierarchy can be mounted with the following mount command.
+hierarchy can be mounted with the following mount command::
# mount -t cgroup2 none $MOUNT_POINT
@@ -150,10 +157,11 @@ and experimenting easier, the kernel parameter cgroup_no_v1= allows
disabling controllers in v1 and make them always available in v2.
-2-2. Organizing Processes
+Organizing Processes
+--------------------
Initially, only the root cgroup exists to which all processes belong.
-A child cgroup can be created by creating a sub-directory.
+A child cgroup can be created by creating a sub-directory::
# mkdir $CGROUP_NAME
@@ -180,28 +188,29 @@ moved to another cgroup.
A cgroup which doesn't have any children or live processes can be
destroyed by removing the directory. Note that a cgroup which doesn't
have any children and is associated only with zombie processes is
-considered empty and can be removed.
+considered empty and can be removed::
# rmdir $CGROUP_NAME
"/proc/$PID/cgroup" lists a process's cgroup membership. If legacy
cgroup is in use in the system, this file may contain multiple lines,
one for each hierarchy. The entry for cgroup v2 is always in the
-format "0::$PATH".
+format "0::$PATH"::
# cat /proc/842/cgroup
...
0::/test-cgroup/test-cgroup-nested
If the process becomes a zombie and the cgroup it was associated with
-is removed subsequently, " (deleted)" is appended to the path.
+is removed subsequently, " (deleted)" is appended to the path::
# cat /proc/842/cgroup
...
0::/test-cgroup/test-cgroup-nested (deleted)
-2-3. [Un]populated Notification
+[Un]populated Notification
+--------------------------
Each non-root cgroup has a "cgroup.events" file which contains
"populated" field indicating whether the cgroup's sub-hierarchy has
@@ -212,7 +221,7 @@ example, to start a clean-up operation after all processes of a given
sub-hierarchy have exited. The populated state updates and
notifications are recursive. Consider the following sub-hierarchy
where the numbers in the parentheses represent the numbers of processes
-in each cgroup.
+in each cgroup::
A(4) - B(0) - C(1)
\ D(0)
@@ -223,18 +232,20 @@ file modified events will be generated on the "cgroup.events" files of
both cgroups.
-2-4. Controlling Controllers
+Controlling Controllers
+-----------------------
-2-4-1. Enabling and Disabling
+Enabling and Disabling
+~~~~~~~~~~~~~~~~~~~~~~
Each cgroup has a "cgroup.controllers" file which lists all
-controllers available for the cgroup to enable.
+controllers available for the cgroup to enable::
# cat cgroup.controllers
cpu io memory
No controller is enabled by default. Controllers can be enabled and
-disabled by writing to the "cgroup.subtree_control" file.
+disabled by writing to the "cgroup.subtree_control" file::
# echo "+cpu +memory -io" > cgroup.subtree_control
@@ -246,7 +257,7 @@ are specified, the last one is effective.
Enabling a controller in a cgroup indicates that the distribution of
the target resource across its immediate children will be controlled.
Consider the following sub-hierarchy. The enabled controllers are
-listed in parentheses.
+listed in parentheses::
A(cpu,memory) - B(memory) - C()
\ D()
@@ -266,7 +277,8 @@ controller interface files - anything which doesn't start with
"cgroup." are owned by the parent rather than the cgroup itself.
-2-4-2. Top-down Constraint
+Top-down Constraint
+~~~~~~~~~~~~~~~~~~~
Resources are distributed top-down and a cgroup can further distribute
a resource only if the resource has been distributed to it from the
@@ -277,7 +289,8 @@ the parent has the controller enabled and a controller can't be
disabled if one or more children have it enabled.
-2-4-3. No Internal Process Constraint
+No Internal Process Constraint
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Non-root cgroups can only distribute resources to their children when
they don't have any processes of their own. In other words, only
@@ -304,9 +317,11 @@ children before enabling controllers in its "cgroup.subtree_control"
file.
-2-5. Delegation
+Delegation
+----------
-2-5-1. Model of Delegation
+Model of Delegation
+~~~~~~~~~~~~~~~~~~~
A cgroup can be delegated to a less privileged user by granting write
access of the directory and its "cgroup.procs" file to the user. Note
@@ -326,7 +341,8 @@ cgroups in or nesting depth of a delegated sub-hierarchy; however,
this may be limited explicitly in the future.
-2-5-2. Delegation Containment
+Delegation Containment
+~~~~~~~~~~~~~~~~~~~~~~
A delegated sub-hierarchy is contained in the sense that processes
can't be moved into or out of the sub-hierarchy by the delegatee. For
@@ -345,7 +361,7 @@ in from or push out to outside the sub-hierarchy.
For an example, let's assume cgroups C0 and C1 have been delegated to
user U0 who created C00, C01 under C0 and C10 under C1 as follows and
-all processes under C0 and C1 belong to U0.
+all processes under C0 and C1 belong to U0::
~~~~~~~~~~~~~ - C0 - C00
~ cgroup ~ \ C01
@@ -360,9 +376,11 @@ not have write access to its "cgroup.procs" files and thus the write
will be denied with -EACCES.
-2-6. Guidelines
+Guidelines
+----------
-2-6-1. Organize Once and Control
+Organize Once and Control
+~~~~~~~~~~~~~~~~~~~~~~~~~
Migrating a process across cgroups is a relatively expensive operation
and stateful resources such as memory are not moved together with the
@@ -378,7 +396,8 @@ distribution can be made by changing controller configuration through
the interface files.
-2-6-2. Avoid Name Collisions
+Avoid Name Collisions
+~~~~~~~~~~~~~~~~~~~~~
Interface files for a cgroup and its children cgroups occupy the same
directory and it is possible to create children cgroups which collide
@@ -396,14 +415,16 @@ cgroup doesn't do anything to prevent name collisions and it's the
user's responsibility to avoid them.
-3. Resource Distribution Models
+Resource Distribution Models
+============================
cgroup controllers implement several resource distribution schemes
depending on the resource type and expected use cases. This section
describes major schemes in use along with their expected behaviors.
-3-1. Weights
+Weights
+-------
A parent's resource is distributed by adding up the weights of all
active children and giving each the fraction matching the ratio of its
@@ -424,7 +445,8 @@ process migrations.
and is an example of this type.
-3-2. Limits
+Limits
+------
A child can only consume upto the configured amount of the resource.
Limits can be over-committed - the sum of the limits of children can
@@ -440,7 +462,8 @@ process migrations.
on an IO device and is an example of this type.
-3-3. Protections
+Protections
+-----------
A cgroup is protected to be allocated upto the configured amount of
the resource if the usages of all its ancestors are under their
@@ -460,7 +483,8 @@ process migrations.
example of this type.
-3-4. Allocations
+Allocations
+-----------
A cgroup is exclusively allocated a certain amount of a finite
resource. Allocations can't be over-committed - the sum of the
@@ -479,12 +503,14 @@ may be rejected.
type.
-4. Interface Files
+Interface Files
+===============
-4-1. Format
+Format
+------
All interface files should be in one of the following formats whenever
-possible.
+possible::
New-line separated values
(when only one value can be written at once)
@@ -519,7 +545,8 @@ can be written at a time. For nested keyed files, the sub key pairs
may be specified in any order and not all pairs have to be specified.
-4-2. Conventions
+Conventions
+-----------
- Settings for a single feature should be contained in a single file.
@@ -555,25 +582,25 @@ may be specified in any order and not all pairs have to be specified.
with "default" as the value must not appear when read.
For example, a setting which is keyed by major:minor device numbers
- with integer values may look like the following.
+ with integer values may look like the following::
# cat cgroup-example-interface-file
default 150
8:0 300
- The default value can be updated by
+ The default value can be updated by::
# echo 125 > cgroup-example-interface-file
- or
+ or::
# echo "default 125" > cgroup-example-interface-file
- An override can be set by
+ An override can be set by::
# echo "8:16 170" > cgroup-example-interface-file
- and cleared by
+ and cleared by::
# echo "8:0 default" > cgroup-example-interface-file
# cat cgroup-example-interface-file
@@ -586,12 +613,12 @@ may be specified in any order and not all pairs have to be specified.
generated on the file.
-4-3. Core Interface Files
+Core Interface Files
+--------------------
All cgroup core files are prefixed with "cgroup."
cgroup.procs
-
A read-write new-line separated values file which exists on
all cgroups.
@@ -617,7 +644,6 @@ All cgroup core files are prefixed with "cgroup."
should be granted along with the containing directory.
cgroup.controllers
-
A read-only space separated values file which exists on all
cgroups.
@@ -625,7 +651,6 @@ All cgroup core files are prefixed with "cgroup."
the cgroup. The controllers are not ordered.
cgroup.subtree_control
-
A read-write space separated values file which exists on all
cgroups. Starts out empty.
@@ -641,23 +666,25 @@ All cgroup core files are prefixed with "cgroup."
operations are specified, either all succeed or all fail.
cgroup.events
-
A read-only flat-keyed file which exists on non-root cgroups.
The following entries are defined. Unless specified
otherwise, a value change in this file generates a file
modified event.
populated
-
1 if the cgroup or its descendants contains any live
processes; otherwise, 0.
-5. Controllers
+Controllers
+===========
-5-1. CPU
+CPU
+---
-[NOTE: The interface for the cpu controller hasn't been merged yet]
+.. note::
+
+ The interface for the cpu controller hasn't been merged yet
The "cpu" controllers regulates distribution of CPU cycles. This
controller implements weight and absolute bandwidth limit models for
@@ -665,36 +692,34 @@ normal scheduling policy and absolute bandwidth allocation model for
realtime scheduling policy.
-5-1-1. CPU Interface Files
+CPU Interface Files
+~~~~~~~~~~~~~~~~~~~
All time durations are in microseconds.
cpu.stat
-
A read-only flat-keyed file which exists on non-root cgroups.
- It reports the following six stats.
+ It reports the following six stats:
- usage_usec
- user_usec
- system_usec
- nr_periods
- nr_throttled
- throttled_usec
+ - usage_usec
+ - user_usec
+ - system_usec
+ - nr_periods
+ - nr_throttled
+ - throttled_usec
cpu.weight
-
A read-write single value file which exists on non-root
cgroups. The default is "100".
The weight in the range [1, 10000].
cpu.max
-
A read-write two value file which exists on non-root cgroups.
The default is "max 100000".
- The maximum bandwidth limit. It's in the following format.
+ The maximum bandwidth limit. It's in the following format::
$MAX $PERIOD
@@ -703,9 +728,10 @@ All time durations are in microseconds.
one number is written, $MAX is updated.
cpu.rt.max
+ .. note::
- [NOTE: The semantics of this file is still under discussion and the
- interface hasn't been merged yet]
+ The semantics of this file is still under discussion and the
+ interface hasn't been merged yet
A read-write two value file which exists on all cgroups.
The default is "0 100000".
@@ -713,7 +739,7 @@ All time durations are in microseconds.
The maximum realtime runtime allocation. Over-committing
configurations are disallowed and process migrations are
rejected if not enough bandwidth is available. It's in the
- following format.
+ following format::
$MAX $PERIOD
@@ -722,7 +748,8 @@ All time durations are in microseconds.
updated.
-5-2. Memory
+Memory
+------
The "memory" controller regulates distribution of memory. Memory is
stateful and implements both limit and protection models. Due to the
@@ -744,14 +771,14 @@ following types of memory usages are tracked.
The above list may expand in the future for better coverage.
-5-2-1. Memory Interface Files
+Memory Interface Files
+~~~~~~~~~~~~~~~~~~~~~~
All memory amounts are in bytes. If a value which is not aligned to
PAGE_SIZE is written, the value may be rounded up to the closest
PAGE_SIZE multiple when read back.
memory.current
-
A read-only single value file which exists on non-root
cgroups.
@@ -759,7 +786,6 @@ PAGE_SIZE multiple when read back.
and its descendants.
memory.low
-
A read-write single value file which exists on non-root
cgroups. The default is "0".
@@ -772,7 +798,6 @@ PAGE_SIZE multiple when read back.
protection is discouraged.
memory.high
-
A read-write single value file which exists on non-root
cgroups. The default is "max".
@@ -785,7 +810,6 @@ PAGE_SIZE multiple when read back.
under extreme conditions the limit may be breached.
memory.max
-
A read-write single value file which exists on non-root
cgroups. The default is "max".
@@ -800,21 +824,18 @@ PAGE_SIZE multiple when read back.
utility is limited to providing the final safety net.
memory.events
-
A read-only flat-keyed file which exists on non-root cgroups.
The following entries are defined. Unless specified
otherwise, a value change in this file generates a file
modified event.
low
-
The number of times the cgroup is reclaimed due to
high memory pressure even though its usage is under
the low boundary. This usually indicates that the low
boundary is over-committed.
high
-
The number of times processes of the cgroup are
throttled and routed to perform direct memory reclaim
because the high memory boundary was exceeded. For a
@@ -823,19 +844,16 @@ PAGE_SIZE multiple when read back.
occurrences are expected.
max
-
The number of times the cgroup's memory usage was
about to go over the max boundary. If direct reclaim
fails to bring it down, the OOM killer is invoked.
oom
-
The number of times the OOM killer has been invoked in
the cgroup. This may not exactly match the number of
processes killed but should generally be close.
memory.stat
-
A read-only flat-keyed file which exists on non-root cgroups.
This breaks down the cgroup's memory footprint into different
@@ -849,73 +867,55 @@ PAGE_SIZE multiple when read back.
fixed position; use the keys to look up specific values!
anon
-
Amount of memory used in anonymous mappings such as
brk(), sbrk(), and mmap(MAP_ANONYMOUS)
file
-
Amount of memory used to cache filesystem data,
including tmpfs and shared memory.
kernel_stack
-
Amount of memory allocated to kernel stacks.
slab
-
Amount of memory used for storing in-kernel data
structures.
sock
-
Amount of memory used in network transmission buffers
shmem
-
Amount of cached filesystem data that is swap-backed,
such as tmpfs, shm segments, shared anonymous mmap()s
file_mapped
-
Amount of cached filesystem data mapped with mmap()
file_dirty
-
Amount of cached filesystem data that was modified but
not yet written back to disk
file_writeback
-
Amount of cached filesystem data that was modified and
is currently being written back to disk
- inactive_anon
- active_anon
- inactive_file
- active_file
- unevictable
-
+ inactive_anon, active_anon, inactive_file, active_file, unevictable
Amount of memory, swap-backed and filesystem-backed,
on the internal memory management lists used by the
page reclaim algorithm
slab_reclaimable
-
Part of "slab" that might be reclaimed, such as
dentries and inodes.
slab_unreclaimable
-
Part of "slab" that cannot be reclaimed on memory
pressure.
pgfault
-
Total number of page faults incurred
pgmajfault
-
Number of major page faults incurred
workingset_refault
@@ -931,7 +931,6 @@ PAGE_SIZE multiple when read back.
Number of times a shadow node has been reclaimed
memory.swap.current
-
A read-only single value file which exists on non-root
cgroups.
@@ -939,7 +938,6 @@ PAGE_SIZE multiple when read back.
and its descendants.
memory.swap.max
-
A read-write single value file which exists on non-root
cgroups. The default is "max".
@@ -947,7 +945,8 @@ PAGE_SIZE multiple when read back.
limit, anonymous meomry of the cgroup will not be swapped out.
-5-2-2. Usage Guidelines
+Usage Guidelines
+~~~~~~~~~~~~~~~~
"memory.high" is the main mechanism to control memory usage.
Over-committing on high limit (sum of high limits > available memory)
@@ -970,7 +969,8 @@ memory; unfortunately, memory pressure monitoring mechanism isn't
implemented yet.
-5-2-3. Memory Ownership
+Memory Ownership
+~~~~~~~~~~~~~~~~
A memory area is charged to the cgroup which instantiated it and stays
charged to the cgroup until the area is released. Migrating a process
@@ -988,7 +988,8 @@ POSIX_FADV_DONTNEED to relinquish the ownership of memory areas
belonging to the affected files to ensure correct memory ownership.
-5-3. IO
+IO
+--
The "io" controller regulates the distribution of IO resources. This
controller implements both weight based and absolute bandwidth or IOPS
@@ -997,28 +998,29 @@ only if cfq-iosched is in use and neither scheme is available for
blk-mq devices.
-5-3-1. IO Interface Files
+IO Interface Files
+~~~~~~~~~~~~~~~~~~
io.stat
-
A read-only nested-keyed file which exists on non-root
cgroups.
Lines are keyed by $MAJ:$MIN device numbers and not ordered.
The following nested keys are defined.
+ ====== ===================
rbytes Bytes read
wbytes Bytes written
rios Number of read IOs
wios Number of write IOs
+ ====== ===================
- An example read output follows.
+ An example read output follows:
8:16 rbytes=1459200 wbytes=314773504 rios=192 wios=353
8:0 rbytes=90430464 wbytes=299008000 rios=8950 wios=1252
io.weight
-
A read-write flat-keyed file which exists on non-root cgroups.
The default is "default 100".
@@ -1032,14 +1034,13 @@ blk-mq devices.
$WEIGHT" or simply "$WEIGHT". Overrides can be set by writing
"$MAJ:$MIN $WEIGHT" and unset by writing "$MAJ:$MIN default".
- An example read output follows.
+ An example read output follows::
default 100
8:16 200
8:0 50
io.max
-
A read-write nested-keyed file which exists on non-root
cgroups.
@@ -1047,10 +1048,12 @@ blk-mq devices.
device numbers and not ordered. The following nested keys are
defined.
+ ===== ==================================
rbps Max read bytes per second
wbps Max write bytes per second
riops Max read IO operations per second
wiops Max write IO operations per second
+ ===== ==================================
When writing, any number of nested key-value pairs can be
specified in any order. "max" can be specified as the value
@@ -1060,24 +1063,25 @@ blk-mq devices.
BPS and IOPS are measured in each IO direction and IOs are
delayed if limit is reached. Temporary bursts are allowed.
- Setting read limit at 2M BPS and write at 120 IOPS for 8:16.
+ Setting read limit at 2M BPS and write at 120 IOPS for 8:16::
echo "8:16 rbps=2097152 wiops=120" > io.max
- Reading returns the following.
+ Reading returns the following::
8:16 rbps=2097152 wbps=max riops=max wiops=120
- Write IOPS limit can be removed by writing the following.
+ Write IOPS limit can be removed by writing the following::
echo "8:16 wiops=max" > io.max
- Reading now returns the following.
+ Reading now returns the following::
8:16 rbps=2097152 wbps=max riops=max wiops=max
-5-3-2. Writeback
+Writeback
+~~~~~~~~~
Page cache is dirtied through buffered writes and shared mmaps and
written asynchronously to the backing filesystem by the writeback
@@ -1125,22 +1129,19 @@ patterns.
The sysctl knobs which affect writeback behavior are applied to cgroup
writeback as follows.
- vm.dirty_background_ratio
- vm.dirty_ratio
-
+ vm.dirty_background_ratio, vm.dirty_ratio
These ratios apply the same to cgroup writeback with the
amount of available memory capped by limits imposed by the
memory controller and system-wide clean memory.
- vm.dirty_background_bytes
- vm.dirty_bytes
-
+ vm.dirty_background_bytes, vm.dirty_bytes
For cgroup writeback, this is calculated into ratio against
total available memory and applied the same way as
vm.dirty[_background]_ratio.
-5-4. PID
+PID
+---
The process number controller is used to allow a cgroup to stop any
new tasks from being fork()'d or clone()'d after a specified limit is
@@ -1155,17 +1156,16 @@ Note that PIDs used in this controller refer to TIDs, process IDs as
used by the kernel.
-5-4-1. PID Interface Files
+PID Interface Files
+~~~~~~~~~~~~~~~~~~~
pids.max
-
A read-write single value file which exists on non-root
cgroups. The default is "max".
Hard limit of number of processes.
pids.current
-
A read-only single value file which exists on all cgroups.
The number of processes currently in the cgroup and its
@@ -1180,12 +1180,14 @@ through fork() or clone(). These will return -EAGAIN if the creation
of a new process would cause a cgroup policy to be violated.
-5-5. RDMA
+RDMA
+----
The "rdma" controller regulates the distribution and accounting of
of RDMA resources.
-5-5-1. RDMA Interface Files
+RDMA Interface Files
+~~~~~~~~~~~~~~~~~~~~
rdma.max
A readwrite nested-keyed file that exists for all the cgroups
@@ -1198,10 +1200,12 @@ of RDMA resources.
The following nested keys are defined.
+ ========== =============================
hca_handle Maximum number of HCA Handles
hca_object Maximum number of HCA Objects
+ ========== =============================
- An example for mlx4 and ocrdma device follows.
+ An example for mlx4 and ocrdma device follows::
mlx4_0 hca_handle=2 hca_object=2000
ocrdma1 hca_handle=3 hca_object=max
@@ -1210,15 +1214,17 @@ of RDMA resources.
A read-only file that describes current resource usage.
It exists for all the cgroup except root.
- An example for mlx4 and ocrdma device follows.
+ An example for mlx4 and ocrdma device follows::
mlx4_0 hca_handle=1 hca_object=20
ocrdma1 hca_handle=1 hca_object=23
-5-6. Misc
+Misc
+----
-5-6-1. perf_event
+perf_event
+~~~~~~~~~~
perf_event controller, if not mounted on a legacy hierarchy, is
automatically enabled on the v2 hierarchy so that perf events can
@@ -1226,9 +1232,11 @@ always be filtered by cgroup v2 path. The controller can still be
moved to a legacy hierarchy after v2 hierarchy is populated.
-6. Namespace
+Namespace
+=========
-6-1. Basics
+Basics
+------
cgroup namespace provides a mechanism to virtualize the view of the
"/proc/$PID/cgroup" file and cgroup mounts. The CLONE_NEWCGROUP clone
@@ -1242,7 +1250,7 @@ Without cgroup namespace, the "/proc/$PID/cgroup" file shows the
complete path of the cgroup of a process. In a container setup where
a set of cgroups and namespaces are intended to isolate processes the
"/proc/$PID/cgroup" file may leak potential system level information
-to the isolated processes. For Example:
+to the isolated processes. For Example::
# cat /proc/self/cgroup
0::/batchjobs/container_id1
@@ -1250,14 +1258,14 @@ to the isolated processes. For Example:
The path '/batchjobs/container_id1' can be considered as system-data
and undesirable to expose to the isolated processes. cgroup namespace
can be used to restrict visibility of this path. For example, before
-creating a cgroup namespace, one would see:
+creating a cgroup namespace, one would see::
# ls -l /proc/self/ns/cgroup
lrwxrwxrwx 1 root root 0 2014-07-15 10:37 /proc/self/ns/cgroup -> cgroup:[4026531835]
# cat /proc/self/cgroup
0::/batchjobs/container_id1
-After unsharing a new namespace, the view changes.
+After unsharing a new namespace, the view changes::
# ls -l /proc/self/ns/cgroup
lrwxrwxrwx 1 root root 0 2014-07-15 10:35 /proc/self/ns/cgroup -> cgroup:[4026532183]
@@ -1275,7 +1283,8 @@ namespace is destroyed. The cgroupns root and the actual cgroups
remain.
-6-2. The Root and Views
+The Root and Views
+------------------
The 'cgroupns root' for a cgroup namespace is the cgroup in which the
process calling unshare(2) is running. For example, if a process in
@@ -1284,7 +1293,7 @@ process calling unshare(2) is running. For example, if a process in
init_cgroup_ns, this is the real root ('/') cgroup.
The cgroupns root cgroup does not change even if the namespace creator
-process later moves to a different cgroup.
+process later moves to a different cgroup::
# ~/unshare -c # unshare cgroupns in some cgroup
# cat /proc/self/cgroup
@@ -1298,7 +1307,7 @@ Each process gets its namespace-specific view of "/proc/$PID/cgroup"
Processes running inside the cgroup namespace will be able to see
cgroup paths (in /proc/self/cgroup) only inside their root cgroup.
-From within an unshared cgroupns:
+From within an unshared cgroupns::
# sleep 100000 &
[1] 7353
@@ -1307,7 +1316,7 @@ From within an unshared cgroupns:
0::/sub_cgrp_1
From the initial cgroup namespace, the real cgroup path will be
-visible:
+visible::
$ cat /proc/7353/cgroup
0::/batchjobs/container_id1/sub_cgrp_1
@@ -1315,7 +1324,7 @@ visible:
From a sibling cgroup namespace (that is, a namespace rooted at a
different cgroup), the cgroup path relative to its own cgroup
namespace root will be shown. For instance, if PID 7353's cgroup
-namespace root is at '/batchjobs/container_id2', then it will see
+namespace root is at '/batchjobs/container_id2', then it will see::
# cat /proc/7353/cgroup
0::/../container_id2/sub_cgrp_1
@@ -1324,13 +1333,14 @@ Note that the relative path always starts with '/' to indicate that
its relative to the cgroup namespace root of the caller.
-6-3. Migration and setns(2)
+Migration and setns(2)
+----------------------
Processes inside a cgroup namespace can move into and out of the
namespace root if they have proper access to external cgroups. For
example, from inside a namespace with cgroupns root at
/batchjobs/container_id1, and assuming that the global hierarchy is
-still accessible inside cgroupns:
+still accessible inside cgroupns::
# cat /proc/7353/cgroup
0::/sub_cgrp_1
@@ -1352,10 +1362,11 @@ namespace. It is expected that the someone moves the attaching
process under the target cgroup namespace root.
-6-4. Interaction with Other Namespaces
+Interaction with Other Namespaces
+---------------------------------
Namespace specific cgroup hierarchy can be mounted by a process
-running inside a non-init cgroup namespace.
+running inside a non-init cgroup namespace::
# mount -t cgroup2 none $MOUNT_POINT
@@ -1368,27 +1379,27 @@ the view of cgroup hierarchy by namespace-private cgroupfs mount
provides a properly isolated cgroup view inside the container.
-P. Information on Kernel Programming
+Information on Kernel Programming
+=================================
This section contains kernel programming information in the areas
where interacting with cgroup is necessary. cgroup core and
controllers are not covered.
-P-1. Filesystem Support for Writeback
+Filesystem Support for Writeback
+--------------------------------
A filesystem can support cgroup writeback by updating
address_space_operations->writepage[s]() to annotate bio's using the
following two functions.
wbc_init_bio(@wbc, @bio)
-
Should be called for each bio carrying writeback data and
associates the bio with the inode's owner cgroup. Can be
called anytime between bio allocation and submission.
wbc_account_io(@wbc, @page, @bytes)
-
Should be called for each data segment being written out.
While this function doesn't care exactly when it's called
during the writeback session, it's the easiest and most
@@ -1409,7 +1420,8 @@ cases by skipping wbc_init_bio() or using bio_associate_blkcg()
directly.
-D. Deprecated v1 Core Features
+Deprecated v1 Core Features
+===========================
- Multiple hierarchies including named ones are not supported.
@@ -1423,9 +1435,11 @@ D. Deprecated v1 Core Features
at the root instead.
-R. Issues with v1 and Rationales for v2
+Issues with v1 and Rationales for v2
+====================================
-R-1. Multiple Hierarchies
+Multiple Hierarchies
+--------------------
cgroup v1 allowed an arbitrary number of hierarchies and each
hierarchy could host any number of controllers. While this seemed to
@@ -1477,7 +1491,8 @@ how memory is distributed beyond a certain level while still wanting
to control how CPU cycles are distributed.
-R-2. Thread Granularity
+Thread Granularity
+------------------
cgroup v1 allowed threads of a process to belong to different cgroups.
This didn't make sense for some controllers and those controllers
@@ -1520,7 +1535,8 @@ misbehaving and poorly abstracted interfaces and kernel exposing and
locked into constructs inadvertently.
-R-3. Competition Between Inner Nodes and Threads
+Competition Between Inner Nodes and Threads
+-------------------------------------------
cgroup v1 allowed threads to be in any cgroups which created an
interesting problem where threads belonging to a parent cgroup and its
@@ -1539,7 +1555,7 @@ simply weren't available for threads.
The io controller implicitly created a hidden leaf node for each
cgroup to host the threads. The hidden leaf had its own copies of all
-the knobs with "leaf_" prefixed. While this allowed equivalent
+the knobs with ``leaf_`` prefixed. While this allowed equivalent
control over internal threads, it was with serious drawbacks. It
always added an extra layer of nesting which wouldn't be necessary
otherwise, made the interface messy and significantly complicated the
@@ -1560,7 +1576,8 @@ This clearly is a problem which needs to be addressed from cgroup core
in a uniform way.
-R-4. Other Interface Issues
+Other Interface Issues
+----------------------
cgroup v1 grew without oversight and developed a large number of
idiosyncrasies and inconsistencies. One issue on the cgroup core side
@@ -1588,9 +1605,11 @@ cgroup v2 establishes common conventions where appropriate and updates
controllers so that they expose minimal and consistent interfaces.
-R-5. Controller Issues and Remedies
+Controller Issues and Remedies
+------------------------------
-R-5-1. Memory
+Memory
+~~~~~~
The original lower boundary, the soft limit, is defined as a limit
that is per default unset. As a result, the set of cgroups that
--
2.9.4
[toc] | [prev] | [next] | [standalone]
| From | Tejun Heo <tj@kernel.org> |
|---|---|
| Date | 2017-05-19 17:00 +0200 |
| Subject | Re: [PATCH 06/31] cgroup-v2.txt: standardize document format |
| Message-ID | <tIRxL-3EK-9@gated-at.bofh.it> |
| In reply to | #1645083 |
Hello, Mauro. On Thu, May 18, 2017 at 10:22:11PM -0300, Mauro Carvalho Chehab wrote: > Each text file under Documentation follows a different > format. Some doesn't even have titles! > > Change its representation to follow the adopted standard, > using ReST markups for it to be parseable by Sphinx: > > - Comment the internal index; > - Use :Date: and :Author: for authorship; > - Mark titles; > - Mark literal blocks; > - Adjust witespaces; > - Mark notes; > - Use table notation for the existing tables. If this is the direction we're taking for all docs, looks good to me. Do you want me to take the patch through the cgroup tree? Thanks. -- tejun
[toc] | [prev] | [next] | [standalone]
| From | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| Date | 2017-05-19 03:50 +0200 |
| Subject | [PATCH 03/31] btmrvl.txt: standardize document format |
| Message-ID | <tIFdg-3gE-15@gated-at.bofh.it> |
| In reply to | #1645017 |
Each text file under Documentation follows a different format. Some doesn't even have titles! Change its representation to follow the adopted standard, using ReST markups for it to be parseable by Sphinx: - Use the right notation for titles; - Use a list for image names; - Use literal blocks where needed; - Whitespace fixes. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> --- Documentation/btmrvl.txt | 64 +++++++++++++++++++++++++----------------------- 1 file changed, 34 insertions(+), 30 deletions(-) diff --git a/Documentation/btmrvl.txt b/Documentation/btmrvl.txt index 34916a46c099..575512415c2b 100644 --- a/Documentation/btmrvl.txt +++ b/Documentation/btmrvl.txt @@ -1,18 +1,15 @@ -======================================================================= - README for btmrvl driver -======================================================================= - +btmrvl driver +============= All commands are used via debugfs interface. -===================== -Set/get driver configurations: +Set/get driver configurations +============================= Path: /debug/btmrvl/config/ -gpiogap=[n] -hscfgcmd - These commands are used to configure the host sleep parameters. +gpiogap=[n], hscfgcmd + These commands are used to configure the host sleep parameters:: bit 8:0 -- Gap bit 16:8 -- GPIO @@ -23,7 +20,8 @@ hscfgcmd where Gap is the gap in milli seconds between wakeup signal and wakeup event, or 0xff for special host sleep setting. - Usage: + Usage:: + # Use SDIO interface to wake up the host and set GAP to 0x80: echo 0xff80 > /debug/btmrvl/config/gpiogap echo 1 > /debug/btmrvl/config/hscfgcmd @@ -32,15 +30,16 @@ hscfgcmd echo 0x03ff > /debug/btmrvl/config/gpiogap echo 1 > /debug/btmrvl/config/hscfgcmd -psmode=[n] -pscmd +psmode=[n], pscmd These commands are used to enable/disable auto sleep mode - where the option is: + where the option is:: + 1 -- Enable auto sleep mode 0 -- Disable auto sleep mode - Usage: + Usage:: + # Enable auto sleep mode echo 1 > /debug/btmrvl/config/psmode echo 1 > /debug/btmrvl/config/pscmd @@ -50,15 +49,16 @@ pscmd echo 1 > /debug/btmrvl/config/pscmd -hsmode=[n] -hscmd +hsmode=[n], hscmd These commands are used to enable host sleep or wake up firmware - where the option is: + where the option is:: + 1 -- Enable host sleep 0 -- Wake up firmware - Usage: + Usage:: + # Enable host sleep echo 1 > /debug/btmrvl/config/hsmode echo 1 > /debug/btmrvl/config/hscmd @@ -68,12 +68,13 @@ hscmd echo 1 > /debug/btmrvl/config/hscmd -====================== -Get driver status: +Get driver status +================= Path: /debug/btmrvl/status/ -Usage: +Usage:: + cat /debug/btmrvl/status/<args> where the args are: @@ -90,14 +91,17 @@ hsstate txdnldrdy This command displays the value of Tx download ready flag. - -===================== +Issuing a raw hci command +========================= Use hcitool to issue raw hci command, refer to hcitool manual - Usage: Hcitool cmd <ogf> <ocf> [Parameters] +Usage:: + + Hcitool cmd <ogf> <ocf> [Parameters] + +Interface Control Command:: - Interface Control Command hcitool cmd 0x3f 0x5b 0xf5 0x01 0x00 --Enable All interface hcitool cmd 0x3f 0x5b 0xf5 0x01 0x01 --Enable Wlan interface hcitool cmd 0x3f 0x5b 0xf5 0x01 0x02 --Enable BT interface @@ -105,13 +109,13 @@ Use hcitool to issue raw hci command, refer to hcitool manual hcitool cmd 0x3f 0x5b 0xf5 0x00 0x01 --Disable Wlan interface hcitool cmd 0x3f 0x5b 0xf5 0x00 0x02 --Disable BT interface -======================================================================= +SD8688 firmware +=============== +Images: -SD8688 firmware: - -/lib/firmware/sd8688_helper.bin -/lib/firmware/sd8688.bin +- /lib/firmware/sd8688_helper.bin +- /lib/firmware/sd8688.bin The images can be downloaded from: -- 2.9.4
[toc] | [prev] | [next] | [standalone]
| From | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| Date | 2017-05-19 03:50 +0200 |
| Subject | [PATCH 22/31] futex-requeue-pi.txt: standardize document format |
| Message-ID | <tIFdg-3gE-17@gated-at.bofh.it> |
| In reply to | #1645017 |
Each text file under Documentation follows a different
format. Some doesn't even have titles!
Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:
- promote level for the document title;
- mark literal blocks.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
---
Documentation/futex-requeue-pi.txt | 83 +++++++++++++++++++-------------------
1 file changed, 42 insertions(+), 41 deletions(-)
diff --git a/Documentation/futex-requeue-pi.txt b/Documentation/futex-requeue-pi.txt
index 77b36f59d16b..14ab5787b9a7 100644
--- a/Documentation/futex-requeue-pi.txt
+++ b/Documentation/futex-requeue-pi.txt
@@ -1,5 +1,6 @@
+================
Futex Requeue PI
-----------------
+================
Requeueing of tasks from a non-PI futex to a PI futex requires
special handling in order to ensure the underlying rt_mutex is never
@@ -20,28 +21,28 @@ implementation would wake the highest-priority waiter, and leave the
rest to the natural wakeup inherent in unlocking the mutex
associated with the condvar.
-Consider the simplified glibc calls:
+Consider the simplified glibc calls::
-/* caller must lock mutex */
-pthread_cond_wait(cond, mutex)
-{
- lock(cond->__data.__lock);
- unlock(mutex);
- do {
- unlock(cond->__data.__lock);
- futex_wait(cond->__data.__futex);
- lock(cond->__data.__lock);
- } while(...)
- unlock(cond->__data.__lock);
- lock(mutex);
-}
+ /* caller must lock mutex */
+ pthread_cond_wait(cond, mutex)
+ {
+ lock(cond->__data.__lock);
+ unlock(mutex);
+ do {
+ unlock(cond->__data.__lock);
+ futex_wait(cond->__data.__futex);
+ lock(cond->__data.__lock);
+ } while(...)
+ unlock(cond->__data.__lock);
+ lock(mutex);
+ }
-pthread_cond_broadcast(cond)
-{
- lock(cond->__data.__lock);
- unlock(cond->__data.__lock);
- futex_requeue(cond->data.__futex, cond->mutex);
-}
+ pthread_cond_broadcast(cond)
+ {
+ lock(cond->__data.__lock);
+ unlock(cond->__data.__lock);
+ futex_requeue(cond->data.__futex, cond->mutex);
+ }
Once pthread_cond_broadcast() requeues the tasks, the cond->mutex
has waiters. Note that pthread_cond_wait() attempts to lock the
@@ -53,29 +54,29 @@ In order to support PI-aware pthread_condvar's, the kernel needs to
be able to requeue tasks to PI futexes. This support implies that
upon a successful futex_wait system call, the caller would return to
user space already holding the PI futex. The glibc implementation
-would be modified as follows:
+would be modified as follows::
-/* caller must lock mutex */
-pthread_cond_wait_pi(cond, mutex)
-{
- lock(cond->__data.__lock);
- unlock(mutex);
- do {
- unlock(cond->__data.__lock);
- futex_wait_requeue_pi(cond->__data.__futex);
- lock(cond->__data.__lock);
- } while(...)
- unlock(cond->__data.__lock);
- /* the kernel acquired the mutex for us */
-}
+ /* caller must lock mutex */
+ pthread_cond_wait_pi(cond, mutex)
+ {
+ lock(cond->__data.__lock);
+ unlock(mutex);
+ do {
+ unlock(cond->__data.__lock);
+ futex_wait_requeue_pi(cond->__data.__futex);
+ lock(cond->__data.__lock);
+ } while(...)
+ unlock(cond->__data.__lock);
+ /* the kernel acquired the mutex for us */
+ }
-pthread_cond_broadcast_pi(cond)
-{
- lock(cond->__data.__lock);
- unlock(cond->__data.__lock);
- futex_requeue_pi(cond->data.__futex, cond->mutex);
-}
+ pthread_cond_broadcast_pi(cond)
+ {
+ lock(cond->__data.__lock);
+ unlock(cond->__data.__lock);
+ futex_requeue_pi(cond->data.__futex, cond->mutex);
+ }
The actual glibc implementation will likely test for PI and make the
necessary changes inside the existing calls rather than creating new
--
2.9.4
[toc] | [prev] | [next] | [standalone]
| From | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| Date | 2017-05-19 03:50 +0200 |
| Subject | [PATCH 08/31] clk.txt: standardize document format |
| Message-ID | <tIFdg-3gE-19@gated-at.bofh.it> |
| In reply to | #1645017 |
Each text file under Documentation follows a different
format. Some doesn't even have titles!
Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:
- Use section/title markups;
- Use :Author: for authorship;
- Mark literals and literal blocks;
- Mark tables;
- Use ReST notation for footnotes.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
---
Documentation/clk.txt | 189 ++++++++++++++++++++++++++++----------------------
1 file changed, 106 insertions(+), 83 deletions(-)
diff --git a/Documentation/clk.txt b/Documentation/clk.txt
index 22f026aa2f34..be909ed45970 100644
--- a/Documentation/clk.txt
+++ b/Documentation/clk.txt
@@ -1,12 +1,16 @@
- The Common Clk Framework
- Mike Turquette <mturquette@ti.com>
+========================
+The Common Clk Framework
+========================
+
+:Author: Mike Turquette <mturquette@ti.com>
This document endeavours to explain the common clk framework details,
and how to port a platform over to this framework. It is not yet a
detailed explanation of the clock api in include/linux/clk.h, but
perhaps someday it will include that information.
- Part 1 - introduction and interface split
+Introduction and interface split
+================================
The common clk framework is an interface to control the clock nodes
available on various devices today. This may come in the form of clock
@@ -35,10 +39,11 @@ is defined in struct clk_foo and pointed to within struct clk_core. This
allows for easy navigation between the two discrete halves of the common
clock interface.
- Part 2 - common data structures and api
+Common data structures and api
+==============================
Below is the common struct clk_core definition from
-drivers/clk/clk.c, modified for brevity:
+drivers/clk/clk.c, modified for brevity::
struct clk_core {
const char *name;
@@ -59,7 +64,7 @@ struct clk. That api is documented in include/linux/clk.h.
Platforms and devices utilizing the common struct clk_core use the struct
clk_ops pointer in struct clk_core to perform the hardware-specific parts of
-the operations defined in clk-provider.h:
+the operations defined in clk-provider.h::
struct clk_ops {
int (*prepare)(struct clk_hw *hw);
@@ -95,19 +100,20 @@ the operations defined in clk-provider.h:
struct dentry *dentry);
};
- Part 3 - hardware clk implementations
+Hardware clk implementations
+============================
The strength of the common struct clk_core comes from its .ops and .hw pointers
which abstract the details of struct clk from the hardware-specific bits, and
vice versa. To illustrate consider the simple gateable clk implementation in
-drivers/clk/clk-gate.c:
+drivers/clk/clk-gate.c::
-struct clk_gate {
- struct clk_hw hw;
- void __iomem *reg;
- u8 bit_idx;
- ...
-};
+ struct clk_gate {
+ struct clk_hw hw;
+ void __iomem *reg;
+ u8 bit_idx;
+ ...
+ };
struct clk_gate contains struct clk_hw hw as well as hardware-specific
knowledge about which register and bit controls this clk's gating.
@@ -115,7 +121,7 @@ Nothing about clock topology or accounting, such as enable_count or
notifier_count, is needed here. That is all handled by the common
framework code and struct clk_core.
-Let's walk through enabling this clk from driver code:
+Let's walk through enabling this clk from driver code::
struct clk *clk;
clk = clk_get(NULL, "my_gateable_clk");
@@ -123,70 +129,71 @@ Let's walk through enabling this clk from driver code:
clk_prepare(clk);
clk_enable(clk);
-The call graph for clk_enable is very simple:
+The call graph for clk_enable is very simple::
-clk_enable(clk);
- clk->ops->enable(clk->hw);
- [resolves to...]
- clk_gate_enable(hw);
- [resolves struct clk gate with to_clk_gate(hw)]
- clk_gate_set_bit(gate);
+ clk_enable(clk);
+ clk->ops->enable(clk->hw);
+ [resolves to...]
+ clk_gate_enable(hw);
+ [resolves struct clk gate with to_clk_gate(hw)]
+ clk_gate_set_bit(gate);
-And the definition of clk_gate_set_bit:
+And the definition of clk_gate_set_bit::
-static void clk_gate_set_bit(struct clk_gate *gate)
-{
- u32 reg;
+ static void clk_gate_set_bit(struct clk_gate *gate)
+ {
+ u32 reg;
- reg = __raw_readl(gate->reg);
- reg |= BIT(gate->bit_idx);
- writel(reg, gate->reg);
-}
+ reg = __raw_readl(gate->reg);
+ reg |= BIT(gate->bit_idx);
+ writel(reg, gate->reg);
+ }
-Note that to_clk_gate is defined as:
+Note that to_clk_gate is defined as::
-#define to_clk_gate(_hw) container_of(_hw, struct clk_gate, hw)
+ #define to_clk_gate(_hw) container_of(_hw, struct clk_gate, hw)
This pattern of abstraction is used for every clock hardware
representation.
- Part 4 - supporting your own clk hardware
+Supporting your own clk hardware
+================================
When implementing support for a new type of clock it is only necessary to
-include the following header:
+include the following header::
-#include <linux/clk-provider.h>
+ #include <linux/clk-provider.h>
To construct a clk hardware structure for your platform you must define
-the following:
+the following::
-struct clk_foo {
- struct clk_hw hw;
- ... hardware specific data goes here ...
-};
+ struct clk_foo {
+ struct clk_hw hw;
+ ... hardware specific data goes here ...
+ };
To take advantage of your data you'll need to support valid operations
-for your clk:
+for your clk::
-struct clk_ops clk_foo_ops {
- .enable = &clk_foo_enable;
- .disable = &clk_foo_disable;
-};
+ struct clk_ops clk_foo_ops {
+ .enable = &clk_foo_enable;
+ .disable = &clk_foo_disable;
+ };
-Implement the above functions using container_of:
+Implement the above functions using container_of::
-#define to_clk_foo(_hw) container_of(_hw, struct clk_foo, hw)
+ #define to_clk_foo(_hw) container_of(_hw, struct clk_foo, hw)
-int clk_foo_enable(struct clk_hw *hw)
-{
- struct clk_foo *foo;
+ int clk_foo_enable(struct clk_hw *hw)
+ {
+ struct clk_foo *foo;
- foo = to_clk_foo(hw);
+ foo = to_clk_foo(hw);
- ... perform magic on foo ...
+ ... perform magic on foo ...
- return 0;
-};
+ return 0;
+ };
Below is a matrix detailing which clk_ops are mandatory based upon the
hardware capabilities of that clock. A cell marked as "y" means
@@ -194,41 +201,56 @@ mandatory, a cell marked as "n" implies that either including that
callback is invalid or otherwise unnecessary. Empty cells are either
optional or must be evaluated on a case-by-case basis.
- clock hardware characteristics
- -----------------------------------------------------------
- | gate | change rate | single parent | multiplexer | root |
- |------|-------------|---------------|-------------|------|
-.prepare | | | | | |
-.unprepare | | | | | |
- | | | | | |
-.enable | y | | | | |
-.disable | y | | | | |
-.is_enabled | y | | | | |
- | | | | | |
-.recalc_rate | | y | | | |
-.round_rate | | y [1] | | | |
-.determine_rate | | y [1] | | | |
-.set_rate | | y | | | |
- | | | | | |
-.set_parent | | | n | y | n |
-.get_parent | | | n | y | n |
- | | | | | |
-.recalc_accuracy| | | | | |
- | | | | | |
-.init | | | | | |
- -----------------------------------------------------------
-[1] either one of round_rate or determine_rate is required.
+.. table:: clock hardware characteristics
+
+ +----------------+------+-------------+---------------+-------------+------+
+ | | gate | change rate | single parent | multiplexer | root |
+ +================+======+=============+===============+=============+======+
+ |.prepare | | | | | |
+ +----------------+------+-------------+---------------+-------------+------+
+ |.unprepare | | | | | |
+ +----------------+------+-------------+---------------+-------------+------+
+ +----------------+------+-------------+---------------+-------------+------+
+ |.enable | y | | | | |
+ +----------------+------+-------------+---------------+-------------+------+
+ |.disable | y | | | | |
+ +----------------+------+-------------+---------------+-------------+------+
+ |.is_enabled | y | | | | |
+ +----------------+------+-------------+---------------+-------------+------+
+ +----------------+------+-------------+---------------+-------------+------+
+ |.recalc_rate | | y | | | |
+ +----------------+------+-------------+---------------+-------------+------+
+ |.round_rate | | y [1]_ | | | |
+ +----------------+------+-------------+---------------+-------------+------+
+ |.determine_rate | | y [1]_ | | | |
+ +----------------+------+-------------+---------------+-------------+------+
+ |.set_rate | | y | | | |
+ +----------------+------+-------------+---------------+-------------+------+
+ +----------------+------+-------------+---------------+-------------+------+
+ |.set_parent | | | n | y | n |
+ +----------------+------+-------------+---------------+-------------+------+
+ |.get_parent | | | n | y | n |
+ +----------------+------+-------------+---------------+-------------+------+
+ +----------------+------+-------------+---------------+-------------+------+
+ |.recalc_accuracy| | | | | |
+ +----------------+------+-------------+---------------+-------------+------+
+ +----------------+------+-------------+---------------+-------------+------+
+ |.init | | | | | |
+ +----------------+------+-------------+---------------+-------------+------+
+
+.. [1] either one of round_rate or determine_rate is required.
Finally, register your clock at run-time with a hardware-specific
registration function. This function simply populates struct clk_foo's
data and then passes the common struct clk parameters to the framework
-with a call to:
+with a call to::
-clk_register(...)
+ clk_register(...)
-See the basic clock types in drivers/clk/clk-*.c for examples.
+See the basic clock types in ``drivers/clk/clk-*.c`` for examples.
- Part 5 - Disabling clock gating of unused clocks
+Disabling clock gating of unused clocks
+=======================================
Sometimes during development it can be useful to be able to bypass the
default disabling of unused clocks. For example, if drivers aren't enabling
@@ -239,7 +261,8 @@ are sorted out.
To bypass this disabling, include "clk_ignore_unused" in the bootargs to the
kernel.
- Part 6 - Locking
+Locking
+=======
The common clock framework uses two global locks, the prepare lock and the
enable lock.
--
2.9.4
[toc] | [prev] | [next] | [standalone]
| From | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| Date | 2017-05-19 03:50 +0200 |
| Subject | [PATCH 07/31] circular-buffers.txt: standardize document format |
| Message-ID | <tIFdg-3gE-21@gated-at.bofh.it> |
| In reply to | #1645017 |
Each text file under Documentation follows a different
format. Some doesn't even have titles!
Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:
- Mark titles with ReST notation;
- comment the contents table;
- Use :Author: tag for authorship;
- mark literal blocks as such;
- use valid numbered list markups;
- Don't capitalize titles.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
---
Documentation/circular-buffers.txt | 51 +++++++++++++++++---------------------
1 file changed, 23 insertions(+), 28 deletions(-)
diff --git a/Documentation/circular-buffers.txt b/Documentation/circular-buffers.txt
index 4a824d232472..d4628174b7c5 100644
--- a/Documentation/circular-buffers.txt
+++ b/Documentation/circular-buffers.txt
@@ -1,9 +1,9 @@
- ================
- CIRCULAR BUFFERS
- ================
+================
+Circular Buffers
+================
-By: David Howells <dhowells@redhat.com>
- Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+:Author: David Howells <dhowells@redhat.com>
+:Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Linux provides a number of features that can be used to implement circular
@@ -20,7 +20,7 @@ producer and just one consumer. It is possible to handle multiple producers by
serialising them, and to handle multiple consumers by serialising them.
-Contents:
+.. Contents:
(*) What is a circular buffer?
@@ -31,8 +31,8 @@ Contents:
- The consumer.
-==========================
-WHAT IS A CIRCULAR BUFFER?
+
+What is a circular buffer?
==========================
First of all, what is a circular buffer? A circular buffer is a buffer of
@@ -60,9 +60,7 @@ buffer, provided that neither index overtakes the other. The implementer must
be careful, however, as a region more than one unit in size may wrap the end of
the buffer and be broken into two segments.
-
-============================
-MEASURING POWER-OF-2 BUFFERS
+Measuring power-of-2 buffers
============================
Calculation of the occupancy or the remaining capacity of an arbitrarily sized
@@ -71,13 +69,13 @@ modulus (divide) instruction. However, if the buffer is of a power-of-2 size,
then a much quicker bitwise-AND instruction can be used instead.
Linux provides a set of macros for handling power-of-2 circular buffers. These
-can be made use of by:
+can be made use of by::
#include <linux/circ_buf.h>
The macros are:
- (*) Measure the remaining capacity of a buffer:
+ (#) Measure the remaining capacity of a buffer::
CIRC_SPACE(head_index, tail_index, buffer_size);
@@ -85,7 +83,7 @@ The macros are:
can be inserted.
- (*) Measure the maximum consecutive immediate space in a buffer:
+ (#) Measure the maximum consecutive immediate space in a buffer::
CIRC_SPACE_TO_END(head_index, tail_index, buffer_size);
@@ -94,14 +92,14 @@ The macros are:
beginning of the buffer.
- (*) Measure the occupancy of a buffer:
+ (#) Measure the occupancy of a buffer::
CIRC_CNT(head_index, tail_index, buffer_size);
This returns the number of items currently occupying a buffer[2].
- (*) Measure the non-wrapping occupancy of a buffer:
+ (#) Measure the non-wrapping occupancy of a buffer::
CIRC_CNT_TO_END(head_index, tail_index, buffer_size);
@@ -112,7 +110,7 @@ The macros are:
Each of these macros will nominally return a value between 0 and buffer_size-1,
however:
- [1] CIRC_SPACE*() are intended to be used in the producer. To the producer
+ (1) CIRC_SPACE*() are intended to be used in the producer. To the producer
they will return a lower bound as the producer controls the head index,
but the consumer may still be depleting the buffer on another CPU and
moving the tail index.
@@ -120,7 +118,7 @@ however:
To the consumer it will show an upper bound as the producer may be busy
depleting the space.
- [2] CIRC_CNT*() are intended to be used in the consumer. To the consumer they
+ (2) CIRC_CNT*() are intended to be used in the consumer. To the consumer they
will return a lower bound as the consumer controls the tail index, but the
producer may still be filling the buffer on another CPU and moving the
head index.
@@ -128,14 +126,12 @@ however:
To the producer it will show an upper bound as the consumer may be busy
emptying the buffer.
- [3] To a third party, the order in which the writes to the indices by the
+ (3) To a third party, the order in which the writes to the indices by the
producer and consumer become visible cannot be guaranteed as they are
independent and may be made on different CPUs - so the result in such a
situation will merely be a guess, and may even be negative.
-
-===========================================
-USING MEMORY BARRIERS WITH CIRCULAR BUFFERS
+Using memory barriers with circular buffers
===========================================
By using memory barriers in conjunction with circular buffers, you can avoid
@@ -152,10 +148,10 @@ time, and only one thing should be emptying a buffer at any one time, but the
two sides can operate simultaneously.
-THE PRODUCER
+The producer
------------
-The producer will look something like this:
+The producer will look something like this::
spin_lock(&producer_lock);
@@ -193,10 +189,10 @@ ordering between the read of the index indicating that the consumer has
vacated a given element and the write by the producer to that same element.
-THE CONSUMER
+The Consumer
------------
-The consumer will look something like this:
+The consumer will look something like this::
spin_lock(&consumer_lock);
@@ -235,8 +231,7 @@ prevents the compiler from tearing the store, and enforces ordering
against previous accesses.
-===============
-FURTHER READING
+Further reading
===============
See also Documentation/memory-barriers.txt for a description of Linux's memory
--
2.9.4
[toc] | [prev] | [next] | [standalone]
| From | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| Date | 2017-05-19 03:50 +0200 |
| Subject | [PATCH 12/31] dcdbas.txt: standardize document format |
| Message-ID | <tIFdg-3gE-25@gated-at.bofh.it> |
| In reply to | #1645017 |
From: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Each text file under Documentation follows a different
format. Some doesn't even have titles!
Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:
- Mark titles;
- Mark literal blocks;
- Mark table.
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
---
Documentation/dcdbas.txt | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)
diff --git a/Documentation/dcdbas.txt b/Documentation/dcdbas.txt
index e1c52e2dc361..309cc57a7c1c 100644
--- a/Documentation/dcdbas.txt
+++ b/Documentation/dcdbas.txt
@@ -1,4 +1,9 @@
+===================================
+Dell Systems Management Base Driver
+===================================
+
Overview
+========
The Dell Systems Management Base Driver provides a sysfs interface for
systems management software such as Dell OpenManage to perform system
@@ -17,6 +22,7 @@ more information about the libsmbios project.
System Management Interrupt
+===========================
On some Dell systems, systems management software must access certain
management information via a system management interrupt (SMI). The SMI data
@@ -24,12 +30,12 @@ buffer must reside in 32-bit address space, and the physical address of the
buffer is required for the SMI. The driver maintains the memory required for
the SMI and provides a way for the application to generate the SMI.
The driver creates the following sysfs entries for systems management
-software to perform these system management interrupts:
+software to perform these system management interrupts::
-/sys/devices/platform/dcdbas/smi_data
-/sys/devices/platform/dcdbas/smi_data_buf_phys_addr
-/sys/devices/platform/dcdbas/smi_data_buf_size
-/sys/devices/platform/dcdbas/smi_request
+ /sys/devices/platform/dcdbas/smi_data
+ /sys/devices/platform/dcdbas/smi_data_buf_phys_addr
+ /sys/devices/platform/dcdbas/smi_data_buf_size
+ /sys/devices/platform/dcdbas/smi_request
Systems management software must perform the following steps to execute
a SMI using this driver:
@@ -43,6 +49,7 @@ a SMI using this driver:
Host Control Action
+===================
Dell OpenManage supports a host control feature that allows the administrator
to perform a power cycle or power off of the system after the OS has finished
@@ -69,12 +76,14 @@ power off host control action using this driver:
Host Control SMI Type
+=====================
The following table shows the value to write to host_control_smi_type to
perform a power cycle or power off host control action:
+=================== =====================
PowerEdge System Host Control SMI Type
----------------- ---------------------
+=================== =====================
300 HC_SMITYPE_TYPE1
1300 HC_SMITYPE_TYPE1
1400 HC_SMITYPE_TYPE2
@@ -87,5 +96,4 @@ PowerEdge System Host Control SMI Type
1655MC HC_SMITYPE_TYPE2
700 HC_SMITYPE_TYPE3
750 HC_SMITYPE_TYPE3
-
-
+=================== =====================
--
2.9.4
[toc] | [prev] | [next] | [standalone]
| From | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| Date | 2017-05-19 03:50 +0200 |
| Subject | [PATCH 25/31] hw_random.txt: standardize document format |
| Message-ID | <tIFdg-3gE-23@gated-at.bofh.it> |
| In reply to | #1645017 |
Each text file under Documentation follows a different format. Some doesn't even have titles! Change its representation to follow the adopted standard, using ReST markups for it to be parseable by Sphinx: - use proper markups for titles; - adjust section identation; - use proper markup for notes and fix it to properly show the numbered list. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> --- Documentation/hw_random.txt | 158 ++++++++++++++++++++++++-------------------- 1 file changed, 86 insertions(+), 72 deletions(-) diff --git a/Documentation/hw_random.txt b/Documentation/hw_random.txt index fce1634907d0..865e997d9d3b 100644 --- a/Documentation/hw_random.txt +++ b/Documentation/hw_random.txt @@ -1,90 +1,104 @@ -Introduction: - - The hw_random framework is software that makes use of a - special hardware feature on your CPU or motherboard, - a Random Number Generator (RNG). The software has two parts: - a core providing the /dev/hwrng character device and its - sysfs support, plus a hardware-specific driver that plugs - into that core. - - To make the most effective use of these mechanisms, you - should download the support software as well. Download the - latest version of the "rng-tools" package from the - hw_random driver's official Web site: - - http://sourceforge.net/projects/gkernel/ - - Those tools use /dev/hwrng to fill the kernel entropy pool, - which is used internally and exported by the /dev/urandom and - /dev/random special files. - -Theory of operation: - - CHARACTER DEVICE. Using the standard open() - and read() system calls, you can read random data from - the hardware RNG device. This data is NOT CHECKED by any - fitness tests, and could potentially be bogus (if the - hardware is faulty or has been tampered with). Data is only - output if the hardware "has-data" flag is set, but nevertheless - a security-conscious person would run fitness tests on the - data before assuming it is truly random. - - The rng-tools package uses such tests in "rngd", and lets you - run them by hand with a "rngtest" utility. - - /dev/hwrng is char device major 10, minor 183. - - CLASS DEVICE. There is a /sys/class/misc/hw_random node with - two unique attributes, "rng_available" and "rng_current". The - "rng_available" attribute lists the hardware-specific drivers - available, while "rng_current" lists the one which is currently - connected to /dev/hwrng. If your system has more than one - RNG available, you may change the one used by writing a name from - the list in "rng_available" into "rng_current". +Linux support for random number generator in i8xx chipsets +========================================================== + +Introduction +============ + +The hw_random framework is software that makes use of a +special hardware feature on your CPU or motherboard, +a Random Number Generator (RNG). The software has two parts: +a core providing the /dev/hwrng character device and its +sysfs support, plus a hardware-specific driver that plugs +into that core. + +To make the most effective use of these mechanisms, you +should download the support software as well. Download the +latest version of the "rng-tools" package from the +hw_random driver's official Web site: + + http://sourceforge.net/projects/gkernel/ + +Those tools use /dev/hwrng to fill the kernel entropy pool, +which is used internally and exported by the /dev/urandom and +/dev/random special files. + +Theory of operation +=================== + +CHARACTER DEVICE. Using the standard open() +and read() system calls, you can read random data from +the hardware RNG device. This data is NOT CHECKED by any +fitness tests, and could potentially be bogus (if the +hardware is faulty or has been tampered with). Data is only +output if the hardware "has-data" flag is set, but nevertheless +a security-conscious person would run fitness tests on the +data before assuming it is truly random. + +The rng-tools package uses such tests in "rngd", and lets you +run them by hand with a "rngtest" utility. + +/dev/hwrng is char device major 10, minor 183. + +CLASS DEVICE. There is a /sys/class/misc/hw_random node with +two unique attributes, "rng_available" and "rng_current". The +"rng_available" attribute lists the hardware-specific drivers +available, while "rng_current" lists the one which is currently +connected to /dev/hwrng. If your system has more than one +RNG available, you may change the one used by writing a name from +the list in "rng_available" into "rng_current". ========================================================================== - Hardware driver for Intel/AMD/VIA Random Number Generators (RNG) - Copyright 2000,2001 Jeff Garzik <jgarzik@pobox.com> - Copyright 2000,2001 Philipp Rumpf <prumpf@mandrakesoft.com> +Hardware driver for Intel/AMD/VIA Random Number Generators (RNG) + - Copyright 2000,2001 Jeff Garzik <jgarzik@pobox.com> + - Copyright 2000,2001 Philipp Rumpf <prumpf@mandrakesoft.com> -About the Intel RNG hardware, from the firmware hub datasheet: - The Firmware Hub integrates a Random Number Generator (RNG) - using thermal noise generated from inherently random quantum - mechanical properties of silicon. When not generating new random - bits the RNG circuitry will enter a low power state. Intel will - provide a binary software driver to give third party software - access to our RNG for use as a security feature. At this time, - the RNG is only to be used with a system in an OS-present state. +About the Intel RNG hardware, from the firmware hub datasheet +============================================================= -Intel RNG Driver notes: +The Firmware Hub integrates a Random Number Generator (RNG) +using thermal noise generated from inherently random quantum +mechanical properties of silicon. When not generating new random +bits the RNG circuitry will enter a low power state. Intel will +provide a binary software driver to give third party software +access to our RNG for use as a security feature. At this time, +the RNG is only to be used with a system in an OS-present state. - * FIXME: support poll(2) +Intel RNG Driver notes +====================== - NOTE: request_mem_region was removed, for three reasons: - 1) Only one RNG is supported by this driver, 2) The location - used by the RNG is a fixed location in MMIO-addressable memory, +FIXME: support poll(2) + +.. note:: + + request_mem_region was removed, for three reasons: + + 1) Only one RNG is supported by this driver; + 2) The location used by the RNG is a fixed location in + MMIO-addressable memory; 3) users with properly working BIOS e820 handling will always - have the region in which the RNG is located reserved, so - request_mem_region calls always fail for proper setups. - However, for people who use mem=XX, BIOS e820 information is - -not- in /proc/iomem, and request_mem_region(RNG_ADDR) can - succeed. + have the region in which the RNG is located reserved, so + request_mem_region calls always fail for proper setups. + However, for people who use mem=XX, BIOS e820 information is + **not** in /proc/iomem, and request_mem_region(RNG_ADDR) can + succeed. -Driver details: +Driver details +============== - Based on: +Based on: Intel 82802AB/82802AC Firmware Hub (FWH) Datasheet - May 1999 Order Number: 290658-002 R + May 1999 Order Number: 290658-002 R - Intel 82802 Firmware Hub: Random Number Generator +Intel 82802 Firmware Hub: + Random Number Generator Programmer's Reference Manual - December 1999 Order Number: 298029-001 R + December 1999 Order Number: 298029-001 R - Intel 82802 Firmware HUB Random Number Generator Driver +Intel 82802 Firmware HUB Random Number Generator Driver Copyright (c) 2000 Matt Sottek <msottek@quiknet.com> - Special thanks to Matt Sottek. I did the "guts", he - did the "brains" and all the testing. +Special thanks to Matt Sottek. I did the "guts", he +did the "brains" and all the testing. -- 2.9.4
[toc] | [prev] | [next] | [standalone]
| From | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| Date | 2017-05-19 03:50 +0200 |
| Subject | [PATCH 21/31] flexible-arrays.txt: standardize document format |
| Message-ID | <tIFdg-3gE-29@gated-at.bofh.it> |
| In reply to | #1645017 |
Each text file under Documentation follows a different
format. Some doesn't even have titles!
Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:
- use :Author: and :Updated: markups;
- use proper markup for the document title;
- mark the literal-blocks.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
---
Documentation/flexible-arrays.txt | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)
diff --git a/Documentation/flexible-arrays.txt b/Documentation/flexible-arrays.txt
index df904aec9904..45aec4d354f7 100644
--- a/Documentation/flexible-arrays.txt
+++ b/Documentation/flexible-arrays.txt
@@ -1,6 +1,8 @@
Using flexible arrays in the kernel
-Last updated for 2.6.32
-Jonathan Corbet <corbet@lwn.net>
+===================================
+
+:Updated: Last updated for 2.6.32
+:Author: Jonathan Corbet <corbet@lwn.net>
Large contiguous memory allocations can be unreliable in the Linux kernel.
Kernel programmers will sometimes respond to this problem by allocating
@@ -26,7 +28,7 @@ operation. It's also worth noting that flexible arrays do no internal
locking at all; if concurrent access to an array is possible, then the
caller must arrange for appropriate mutual exclusion.
-The creation of a flexible array is done with:
+The creation of a flexible array is done with::
#include <linux/flex_array.h>
@@ -40,14 +42,14 @@ argument is passed directly to the internal memory allocation calls. With
the current code, using flags to ask for high memory is likely to lead to
notably unpleasant side effects.
-It is also possible to define flexible arrays at compile time with:
+It is also possible to define flexible arrays at compile time with::
DEFINE_FLEX_ARRAY(name, element_size, total);
This macro will result in a definition of an array with the given name; the
element size and total will be checked for validity at compile time.
-Storing data into a flexible array is accomplished with a call to:
+Storing data into a flexible array is accomplished with a call to::
int flex_array_put(struct flex_array *array, unsigned int element_nr,
void *src, gfp_t flags);
@@ -63,7 +65,7 @@ running in some sort of atomic context; in this situation, sleeping in the
memory allocator would be a bad thing. That can be avoided by using
GFP_ATOMIC for the flags value, but, often, there is a better way. The
trick is to ensure that any needed memory allocations are done before
-entering atomic context, using:
+entering atomic context, using::
int flex_array_prealloc(struct flex_array *array, unsigned int start,
unsigned int nr_elements, gfp_t flags);
@@ -73,7 +75,7 @@ defined by start and nr_elements has been allocated. Thereafter, a
flex_array_put() call on an element in that range is guaranteed not to
block.
-Getting data back out of the array is done with:
+Getting data back out of the array is done with::
void *flex_array_get(struct flex_array *fa, unsigned int element_nr);
@@ -89,7 +91,7 @@ involving that number probably result from use of unstored array entries.
Note that, if array elements are allocated with __GFP_ZERO, they will be
initialized to zero and this poisoning will not happen.
-Individual elements in the array can be cleared with:
+Individual elements in the array can be cleared with::
int flex_array_clear(struct flex_array *array, unsigned int element_nr);
@@ -97,7 +99,7 @@ This function will set the given element to FLEX_ARRAY_FREE and return
zero. If storage for the indicated element is not allocated for the array,
flex_array_clear() will return -EINVAL instead. Note that clearing an
element does not release the storage associated with it; to reduce the
-allocated size of an array, call:
+allocated size of an array, call::
int flex_array_shrink(struct flex_array *array);
@@ -106,12 +108,12 @@ This function works by scanning the array for pages containing nothing but
FLEX_ARRAY_FREE bytes, so (1) it can be expensive, and (2) it will not work
if the array's pages are allocated with __GFP_ZERO.
-It is possible to remove all elements of an array with a call to:
+It is possible to remove all elements of an array with a call to::
void flex_array_free_parts(struct flex_array *array);
This call frees all elements, but leaves the array itself in place.
-Freeing the entire array is done with:
+Freeing the entire array is done with::
void flex_array_free(struct flex_array *array);
--
2.9.4
[toc] | [prev] | [next] | [standalone]
| From | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| Date | 2017-05-19 03:50 +0200 |
| Subject | [PATCH 01/31] bcache.txt: standardize document format |
| Message-ID | <tIFdg-3gE-9@gated-at.bofh.it> |
| In reply to | #1645017 |
Each text file under Documentation follows a different
format. Some doesn't even have titles!
Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:
- Add a title for the document;
- Use a list for the listed URLs;
- mark literal blocks;
- adjust whitespaces;
- Don't capitalize section titles.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
---
Documentation/bcache.txt | 200 ++++++++++++++++++++++++++---------------------
1 file changed, 112 insertions(+), 88 deletions(-)
diff --git a/Documentation/bcache.txt b/Documentation/bcache.txt
index a9259b562d5c..c0ce64d75bbf 100644
--- a/Documentation/bcache.txt
+++ b/Documentation/bcache.txt
@@ -1,10 +1,15 @@
+============================
+A block layer cache (bcache)
+============================
+
Say you've got a big slow raid 6, and an ssd or three. Wouldn't it be
nice if you could use them as cache... Hence bcache.
Wiki and git repositories are at:
- http://bcache.evilpiepirate.org
- http://evilpiepirate.org/git/linux-bcache.git
- http://evilpiepirate.org/git/bcache-tools.git
+
+ - http://bcache.evilpiepirate.org
+ - http://evilpiepirate.org/git/linux-bcache.git
+ - http://evilpiepirate.org/git/bcache-tools.git
It's designed around the performance characteristics of SSDs - it only allocates
in erase block sized buckets, and it uses a hybrid btree/log to track cached
@@ -37,17 +42,19 @@ to be flushed.
Getting started:
You'll need make-bcache from the bcache-tools repository. Both the cache device
-and backing device must be formatted before use.
+and backing device must be formatted before use::
+
make-bcache -B /dev/sdb
make-bcache -C /dev/sdc
make-bcache has the ability to format multiple devices at the same time - if
you format your backing devices and cache device at the same time, you won't
-have to manually attach:
+have to manually attach::
+
make-bcache -B /dev/sda /dev/sdb -C /dev/sdc
bcache-tools now ships udev rules, and bcache devices are known to the kernel
-immediately. Without udev, you can manually register devices like this:
+immediately. Without udev, you can manually register devices like this::
echo /dev/sdb > /sys/fs/bcache/register
echo /dev/sdc > /sys/fs/bcache/register
@@ -60,16 +67,16 @@ slow devices as bcache backing devices without a cache, and you can choose to ad
a caching device later.
See 'ATTACHING' section below.
-The devices show up as:
+The devices show up as::
/dev/bcache<N>
-As well as (with udev):
+As well as (with udev)::
/dev/bcache/by-uuid/<uuid>
/dev/bcache/by-label/<label>
-To get started:
+To get started::
mkfs.ext4 /dev/bcache0
mount /dev/bcache0 /mnt
@@ -81,13 +88,13 @@ Cache devices are managed as sets; multiple caches per set isn't supported yet
but will allow for mirroring of metadata and dirty data in the future. Your new
cache set shows up as /sys/fs/bcache/<UUID>
-ATTACHING
+Attaching
---------
After your cache device and backing device are registered, the backing device
must be attached to your cache set to enable caching. Attaching a backing
device to a cache set is done thusly, with the UUID of the cache set in
-/sys/fs/bcache:
+/sys/fs/bcache::
echo <CSET-UUID> > /sys/block/bcache0/bcache/attach
@@ -97,7 +104,7 @@ your bcache devices. If a backing device has data in a cache somewhere, the
important if you have writeback caching turned on.
If you're booting up and your cache device is gone and never coming back, you
-can force run the backing device:
+can force run the backing device::
echo 1 > /sys/block/sdb/bcache/running
@@ -110,7 +117,7 @@ but all the cached data will be invalidated. If there was dirty data in the
cache, don't expect the filesystem to be recoverable - you will have massive
filesystem corruption, though ext4's fsck does work miracles.
-ERROR HANDLING
+Error Handling
--------------
Bcache tries to transparently handle IO errors to/from the cache device without
@@ -134,25 +141,27 @@ the backing devices to passthrough mode.
read some of the dirty data, though.
-HOWTO/COOKBOOK
+Howto/cookbook
--------------
A) Starting a bcache with a missing caching device
If registering the backing device doesn't help, it's already there, you just need
-to force it to run without the cache:
+to force it to run without the cache::
+
host:~# echo /dev/sdb1 > /sys/fs/bcache/register
[ 119.844831] bcache: register_bcache() error opening /dev/sdb1: device already registered
Next, you try to register your caching device if it's present. However
if it's absent, or registration fails for some reason, you can still
-start your bcache without its cache, like so:
+start your bcache without its cache, like so::
+
host:/sys/block/sdb/sdb1/bcache# echo 1 > running
Note that this may cause data loss if you were running in writeback mode.
-B) Bcache does not find its cache
+B) Bcache does not find its cache::
host:/sys/block/md5/bcache# echo 0226553a-37cf-41d5-b3ce-8b1e944543a8 > attach
[ 1933.455082] bcache: bch_cached_dev_attach() Couldn't find uuid for md5 in set
@@ -160,7 +169,8 @@ B) Bcache does not find its cache
[ 1933.478179] : cache set not found
In this case, the caching device was simply not registered at boot
-or disappeared and came back, and needs to be (re-)registered:
+or disappeared and came back, and needs to be (re-)registered::
+
host:/sys/block/md5/bcache# echo /dev/sdh2 > /sys/fs/bcache/register
@@ -180,7 +190,8 @@ device is still available at an 8KiB offset. So either via a loopdev
of the backing device created with --offset 8K, or any value defined by
--data-offset when you originally formatted bcache with `make-bcache`.
-For example:
+For example::
+
losetup -o 8192 /dev/loop0 /dev/your_bcache_backing_dev
This should present your unmodified backing device data in /dev/loop0
@@ -191,33 +202,38 @@ cache device without loosing data.
E) Wiping a cache device
-host:~# wipefs -a /dev/sdh2
-16 bytes were erased at offset 0x1018 (bcache)
-they were: c6 85 73 f6 4e 1a 45 ca 82 65 f5 7f 48 ba 6d 81
-
-After you boot back with bcache enabled, you recreate the cache and attach it:
-host:~# make-bcache -C /dev/sdh2
-UUID: 7be7e175-8f4c-4f99-94b2-9c904d227045
-Set UUID: 5bc072a8-ab17-446d-9744-e247949913c1
-version: 0
-nbuckets: 106874
-block_size: 1
-bucket_size: 1024
-nr_in_set: 1
-nr_this_dev: 0
-first_bucket: 1
-[ 650.511912] bcache: run_cache_set() invalidating existing data
-[ 650.549228] bcache: register_cache() registered cache device sdh2
-
-start backing device with missing cache:
-host:/sys/block/md5/bcache# echo 1 > running
-
-attach new cache:
-host:/sys/block/md5/bcache# echo 5bc072a8-ab17-446d-9744-e247949913c1 > attach
-[ 865.276616] bcache: bch_cached_dev_attach() Caching md5 as bcache0 on set 5bc072a8-ab17-446d-9744-e247949913c1
-
-
-F) Remove or replace a caching device
+::
+
+ host:~# wipefs -a /dev/sdh2
+ 16 bytes were erased at offset 0x1018 (bcache)
+ they were: c6 85 73 f6 4e 1a 45 ca 82 65 f5 7f 48 ba 6d 81
+
+After you boot back with bcache enabled, you recreate the cache and attach it::
+
+ host:~# make-bcache -C /dev/sdh2
+ UUID: 7be7e175-8f4c-4f99-94b2-9c904d227045
+ Set UUID: 5bc072a8-ab17-446d-9744-e247949913c1
+ version: 0
+ nbuckets: 106874
+ block_size: 1
+ bucket_size: 1024
+ nr_in_set: 1
+ nr_this_dev: 0
+ first_bucket: 1
+ [ 650.511912] bcache: run_cache_set() invalidating existing data
+ [ 650.549228] bcache: register_cache() registered cache device sdh2
+
+start backing device with missing cache::
+
+ host:/sys/block/md5/bcache# echo 1 > running
+
+attach new cache::
+
+ host:/sys/block/md5/bcache# echo 5bc072a8-ab17-446d-9744-e247949913c1 > attach
+ [ 865.276616] bcache: bch_cached_dev_attach() Caching md5 as bcache0 on set 5bc072a8-ab17-446d-9744-e247949913c1
+
+
+F) Remove or replace a caching device::
host:/sys/block/sda/sda7/bcache# echo 1 > detach
[ 695.872542] bcache: cached_dev_detach_finish() Caching disabled for sda7
@@ -226,13 +242,15 @@ F) Remove or replace a caching device
wipefs: error: /dev/nvme0n1p4: probing initialization failed: Device or resource busy
Ooops, it's disabled, but not unregistered, so it's still protected
-We need to go and unregister it:
+We need to go and unregister it::
+
host:/sys/fs/bcache/b7ba27a1-2398-4649-8ae3-0959f57ba128# ls -l cache0
lrwxrwxrwx 1 root root 0 Feb 25 18:33 cache0 -> ../../../devices/pci0000:00/0000:00:1d.0/0000:70:00.0/nvme/nvme0/nvme0n1/nvme0n1p4/bcache/
host:/sys/fs/bcache/b7ba27a1-2398-4649-8ae3-0959f57ba128# echo 1 > stop
kernel: [ 917.041908] bcache: cache_set_free() Cache set b7ba27a1-2398-4649-8ae3-0959f57ba128 unregistered
-Now we can wipe it:
+Now we can wipe it::
+
host:~# wipefs -a /dev/nvme0n1p4
/dev/nvme0n1p4: 16 bytes were erased at offset 0x00001018 (bcache): c6 85 73 f6 4e 1a 45 ca 82 65 f5 7f 48 ba 6d 81
@@ -252,40 +270,44 @@ if there are any active backing or caching devices left on it:
1) Is it present in /dev/bcache* ? (there are times where it won't be)
-If so, it's easy:
+ If so, it's easy::
+
host:/sys/block/bcache0/bcache# echo 1 > stop
-2) But if your backing device is gone, this won't work:
+2) But if your backing device is gone, this won't work::
+
host:/sys/block/bcache0# cd bcache
bash: cd: bcache: No such file or directory
-In this case, you may have to unregister the dmcrypt block device that
-references this bcache to free it up:
+ In this case, you may have to unregister the dmcrypt block device that
+ references this bcache to free it up::
+
host:~# dmsetup remove oldds1
bcache: bcache_device_free() bcache0 stopped
bcache: cache_set_free() Cache set 5bc072a8-ab17-446d-9744-e247949913c1 unregistered
-This causes the backing bcache to be removed from /sys/fs/bcache and
-then it can be reused. This would be true of any block device stacking
-where bcache is a lower device.
+ This causes the backing bcache to be removed from /sys/fs/bcache and
+ then it can be reused. This would be true of any block device stacking
+ where bcache is a lower device.
-3) In other cases, you can also look in /sys/fs/bcache/:
+3) In other cases, you can also look in /sys/fs/bcache/::
-host:/sys/fs/bcache# ls -l */{cache?,bdev?}
-lrwxrwxrwx 1 root root 0 Mar 5 09:39 0226553a-37cf-41d5-b3ce-8b1e944543a8/bdev1 -> ../../../devices/virtual/block/dm-1/bcache/
-lrwxrwxrwx 1 root root 0 Mar 5 09:39 0226553a-37cf-41d5-b3ce-8b1e944543a8/cache0 -> ../../../devices/virtual/block/dm-4/bcache/
-lrwxrwxrwx 1 root root 0 Mar 5 09:39 5bc072a8-ab17-446d-9744-e247949913c1/cache0 -> ../../../devices/pci0000:00/0000:00:01.0/0000:01:00.0/ata10/host9/target9:0:0/9:0:0:0/block/sdl/sdl2/bcache/
+ host:/sys/fs/bcache# ls -l */{cache?,bdev?}
+ lrwxrwxrwx 1 root root 0 Mar 5 09:39 0226553a-37cf-41d5-b3ce-8b1e944543a8/bdev1 -> ../../../devices/virtual/block/dm-1/bcache/
+ lrwxrwxrwx 1 root root 0 Mar 5 09:39 0226553a-37cf-41d5-b3ce-8b1e944543a8/cache0 -> ../../../devices/virtual/block/dm-4/bcache/
+ lrwxrwxrwx 1 root root 0 Mar 5 09:39 5bc072a8-ab17-446d-9744-e247949913c1/cache0 -> ../../../devices/pci0000:00/0000:00:01.0/0000:01:00.0/ata10/host9/target9:0:0/9:0:0:0/block/sdl/sdl2/bcache/
+
+ The device names will show which UUID is relevant, cd in that directory
+ and stop the cache::
-The device names will show which UUID is relevant, cd in that directory
-and stop the cache:
host:/sys/fs/bcache/5bc072a8-ab17-446d-9744-e247949913c1# echo 1 > stop
-This will free up bcache references and let you reuse the partition for
-other purposes.
+ This will free up bcache references and let you reuse the partition for
+ other purposes.
-TROUBLESHOOTING PERFORMANCE
+Troubleshooting performance
---------------------------
Bcache has a bunch of config options and tunables. The defaults are intended to
@@ -301,11 +323,13 @@ want for getting the best possible numbers when benchmarking.
raid stripe size to get the disk multiples that you would like.
For example: If you have a 64k stripe size, then the following offset
- would provide alignment for many common RAID5 data spindle counts:
+ would provide alignment for many common RAID5 data spindle counts::
+
64k * 2*2*2*3*3*5*7 bytes = 161280k
That space is wasted, but for only 157.5MB you can grow your RAID 5
- volume to the following data-spindle counts without re-aligning:
+ volume to the following data-spindle counts without re-aligning::
+
3,4,5,6,7,8,9,10,12,14,15,18,20,21 ...
- Bad write performance
@@ -313,9 +337,9 @@ want for getting the best possible numbers when benchmarking.
If write performance is not what you expected, you probably wanted to be
running in writeback mode, which isn't the default (not due to a lack of
maturity, but simply because in writeback mode you'll lose data if something
- happens to your SSD)
+ happens to your SSD)::
- # echo writeback > /sys/block/bcache0/bcache/cache_mode
+ # echo writeback > /sys/block/bcache0/bcache/cache_mode
- Bad performance, or traffic not going to the SSD that you'd expect
@@ -325,13 +349,13 @@ want for getting the best possible numbers when benchmarking.
accessed data out of your cache.
But if you want to benchmark reads from cache, and you start out with fio
- writing an 8 gigabyte test file - so you want to disable that.
+ writing an 8 gigabyte test file - so you want to disable that::
- # echo 0 > /sys/block/bcache0/bcache/sequential_cutoff
+ # echo 0 > /sys/block/bcache0/bcache/sequential_cutoff
- To set it back to the default (4 mb), do
+ To set it back to the default (4 mb), do::
- # echo 4M > /sys/block/bcache0/bcache/sequential_cutoff
+ # echo 4M > /sys/block/bcache0/bcache/sequential_cutoff
- Traffic's still going to the spindle/still getting cache misses
@@ -344,10 +368,10 @@ want for getting the best possible numbers when benchmarking.
throttles traffic if the latency exceeds a threshold (it does this by
cranking down the sequential bypass).
- You can disable this if you need to by setting the thresholds to 0:
+ You can disable this if you need to by setting the thresholds to 0::
- # echo 0 > /sys/fs/bcache/<cache set>/congested_read_threshold_us
- # echo 0 > /sys/fs/bcache/<cache set>/congested_write_threshold_us
+ # echo 0 > /sys/fs/bcache/<cache set>/congested_read_threshold_us
+ # echo 0 > /sys/fs/bcache/<cache set>/congested_write_threshold_us
The default is 2000 us (2 milliseconds) for reads, and 20000 for writes.
@@ -369,7 +393,7 @@ want for getting the best possible numbers when benchmarking.
a fix for the issue there).
-SYSFS - BACKING DEVICE
+Sysfs - backing device
----------------------
Available at /sys/block/<bdev>/bcache, /sys/block/bcache*/bcache and
@@ -454,7 +478,8 @@ writeback_running
still be added to the cache until it is mostly full; only meant for
benchmarking. Defaults to on.
-SYSFS - BACKING DEVICE STATS:
+Sysfs - backing device stats
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
There are directories with these numbers for a running total, as well as
versions that decay over the past day, hour and 5 minutes; they're also
@@ -463,14 +488,11 @@ aggregated in the cache set directory as well.
bypassed
Amount of IO (both reads and writes) that has bypassed the cache
-cache_hits
-cache_misses
-cache_hit_ratio
+cache_hits, cache_misses, cache_hit_ratio
Hits and misses are counted per individual IO as bcache sees them; a
partial hit is counted as a miss.
-cache_bypass_hits
-cache_bypass_misses
+cache_bypass_hits, cache_bypass_misses
Hits and misses for IO that is intended to skip the cache are still counted,
but broken out here.
@@ -482,7 +504,8 @@ cache_miss_collisions
cache_readaheads
Count of times readahead occurred.
-SYSFS - CACHE SET:
+Sysfs - cache set
+~~~~~~~~~~~~~~~~~
Available at /sys/fs/bcache/<cset-uuid>
@@ -520,8 +543,7 @@ flash_vol_create
Echoing a size to this file (in human readable units, k/M/G) creates a thinly
provisioned volume backed by the cache set.
-io_error_halflife
-io_error_limit
+io_error_halflife, io_error_limit
These determines how many errors we accept before disabling the cache.
Each error is decayed by the half life (in # ios). If the decaying count
reaches io_error_limit dirty data is written out and the cache is disabled.
@@ -545,7 +567,8 @@ unregister
Detaches all backing devices and closes the cache devices; if dirty data is
present it will disable writeback caching and wait for it to be flushed.
-SYSFS - CACHE SET INTERNAL:
+Sysfs - cache set internal
+~~~~~~~~~~~~~~~~~~~~~~~~~~
This directory also exposes timings for a number of internal operations, with
separate files for average duration, average frequency, last occurrence and max
@@ -574,7 +597,8 @@ cache_read_races
trigger_gc
Writing to this file forces garbage collection to run.
-SYSFS - CACHE DEVICE:
+Sysfs - Cache device
+~~~~~~~~~~~~~~~~~~~~
Available at /sys/block/<cdev>/bcache
--
2.9.4
[toc] | [prev] | [next] | [standalone]
| From | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| Date | 2017-05-19 03:50 +0200 |
| Subject | [PATCH 04/31] bus-virt-phys-mapping.txt: standardize document format |
| Message-ID | <tIFdg-3gE-31@gated-at.bofh.it> |
| In reply to | #1645017 |
Each text file under Documentation follows a different format. Some doesn't even have titles! Change its representation to follow the adopted standard, using ReST markups for it to be parseable by Sphinx: - Move author info to the beginning of file and use :Author: - use warning/note annotation; - mark literal blocks as such; - Add a title for the document; - use **emphasis** instead of _emphasis_. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> --- Documentation/bus-virt-phys-mapping.txt | 63 +++++++++++++++++++-------------- 1 file changed, 37 insertions(+), 26 deletions(-) diff --git a/Documentation/bus-virt-phys-mapping.txt b/Documentation/bus-virt-phys-mapping.txt index 2bc55ff3b4d1..26918b64bd6b 100644 --- a/Documentation/bus-virt-phys-mapping.txt +++ b/Documentation/bus-virt-phys-mapping.txt @@ -1,17 +1,26 @@ -[ NOTE: The virt_to_bus() and bus_to_virt() functions have been +How to access I/O mapped memory from within device drivers +========================================================== + +:Author: Linus + +.. warning:: + + The virt_to_bus() and bus_to_virt() functions have been superseded by the functionality provided by the PCI DMA interface (see Documentation/DMA-API-HOWTO.txt). They continue to be documented below for historical purposes, but new code - must not use them. --davidm 00/12/12 ] + must not use them. --davidm 00/12/12 -[ This is a mail message in response to a query on IO mapping, thus the - strange format for a "document" ] +:: + + [ This is a mail message in response to a query on IO mapping, thus the + strange format for a "document" ] The AHA-1542 is a bus-master device, and your patch makes the driver give the controller the physical address of the buffers, which is correct on x86 (because all bus master devices see the physical memory mappings directly). -However, on many setups, there are actually _three_ different ways of looking +However, on many setups, there are actually **three** different ways of looking at memory addresses, and in this case we actually want the third, the so-called "bus address". @@ -38,7 +47,7 @@ because the memory and the devices share the same address space, and that is not generally necessarily true on other PCI/ISA setups. Now, just as an example, on the PReP (PowerPC Reference Platform), the -CPU sees a memory map something like this (this is from memory): +CPU sees a memory map something like this (this is from memory):: 0-2 GB "real memory" 2 GB-3 GB "system IO" (inb/out and similar accesses on x86) @@ -52,7 +61,7 @@ So when the CPU wants any bus master to write to physical memory 0, it has to give the master address 0x80000000 as the memory address. So, for example, depending on how the kernel is actually mapped on the -PPC, you can end up with a setup like this: +PPC, you can end up with a setup like this:: physical address: 0 virtual address: 0xC0000000 @@ -61,7 +70,7 @@ PPC, you can end up with a setup like this: where all the addresses actually point to the same thing. It's just seen through different translations.. -Similarly, on the Alpha, the normal translation is +Similarly, on the Alpha, the normal translation is:: physical address: 0 virtual address: 0xfffffc0000000000 @@ -70,7 +79,7 @@ Similarly, on the Alpha, the normal translation is (but there are also Alphas where the physical address and the bus address are the same). -Anyway, the way to look up all these translations, you do +Anyway, the way to look up all these translations, you do:: #include <asm/io.h> @@ -81,8 +90,8 @@ Anyway, the way to look up all these translations, you do Now, when do you need these? -You want the _virtual_ address when you are actually going to access that -pointer from the kernel. So you can have something like this: +You want the **virtual** address when you are actually going to access that +pointer from the kernel. So you can have something like this:: /* * this is the hardware "mailbox" we use to communicate with @@ -104,7 +113,7 @@ pointer from the kernel. So you can have something like this: ... on the other hand, you want the bus address when you have a buffer that -you want to give to the controller: +you want to give to the controller:: /* ask the controller to read the sense status into "sense_buffer" */ mbox.bufstart = virt_to_bus(&sense_buffer); @@ -112,7 +121,7 @@ you want to give to the controller: mbox.status = 0; notify_controller(&mbox); -And you generally _never_ want to use the physical address, because you can't +And you generally **never** want to use the physical address, because you can't use that from the CPU (the CPU only uses translated virtual addresses), and you can't use it from the bus master. @@ -124,8 +133,10 @@ be remapped as measured in units of pages, a.k.a. the pfn (the memory management layer doesn't know about devices outside the CPU, so it shouldn't need to know about "bus addresses" etc). -NOTE NOTE NOTE! The above is only one part of the whole equation. The above -only talks about "real memory", that is, CPU memory (RAM). +.. note:: + + The above is only one part of the whole equation. The above + only talks about "real memory", that is, CPU memory (RAM). There is a completely different type of memory too, and that's the "shared memory" on the PCI or ISA bus. That's generally not RAM (although in the case @@ -137,20 +148,22 @@ whatever, and there is only one way to access it: the readb/writeb and related functions. You should never take the address of such memory, because there is really nothing you can do with such an address: it's not conceptually in the same memory space as "real memory" at all, so you cannot -just dereference a pointer. (Sadly, on x86 it _is_ in the same memory space, +just dereference a pointer. (Sadly, on x86 it **is** in the same memory space, so on x86 it actually works to just deference a pointer, but it's not portable). -For such memory, you can do things like +For such memory, you can do things like: + + - reading:: - - reading: /* * read first 32 bits from ISA memory at 0xC0000, aka * C000:0000 in DOS terms */ unsigned int signature = isa_readl(0xC0000); - - remapping and writing: + - remapping and writing:: + /* * remap framebuffer PCI memory area at 0xFC000000, * size 1MB, so that we can access it: We can directly @@ -165,7 +178,8 @@ For such memory, you can do things like /* unmap when we unload the driver */ iounmap(baseptr); - - copying and clearing: + - copying and clearing:: + /* get the 6-byte Ethernet address at ISA address E000:0040 */ memcpy_fromio(kernel_buffer, 0xE0040, 6); /* write a packet to the driver */ @@ -181,10 +195,10 @@ happy that your driver works ;) Note that kernel versions 2.0.x (and earlier) mistakenly called the ioremap() function "vremap()". ioremap() is the proper name, but I didn't think straight when I wrote it originally. People who have to -support both can do something like: +support both can do something like:: /* support old naming silliness */ - #if LINUX_VERSION_CODE < 0x020100 + #if LINUX_VERSION_CODE < 0x020100 #define ioremap vremap #define iounmap vfree #endif @@ -196,13 +210,10 @@ And the above sounds worse than it really is. Most real drivers really don't do all that complex things (or rather: the complexity is not so much in the actual IO accesses as in error handling and timeouts etc). It's generally not hard to fix drivers, and in many cases the code -actually looks better afterwards: +actually looks better afterwards:: unsigned long signature = *(unsigned int *) 0xC0000; vs unsigned long signature = readl(0xC0000); I think the second version actually is more readable, no? - - Linus - -- 2.9.4
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| From | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| Date | 2017-05-19 03:50 +0200 |
| Subject | [PATCH 23/31] gcc-plugins.txt: standardize document format |
| Message-ID | <tIFdh-3gE-35@gated-at.bofh.it> |
| In reply to | #1645017 |
Each text file under Documentation follows a different format. Some doesn't even have titles! Change its representation to follow the adopted standard, using ReST markups for it to be parseable by Sphinx: - promote main title; - use the right markup for footnotes; - use bold markup for files name; - identify literal blocks; - add blank lines to avoid Sphinx to complain; - remove numeration from titles. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> --- Documentation/gcc-plugins.txt | 58 ++++++++++++++++++++++++------------------- 1 file changed, 32 insertions(+), 26 deletions(-) diff --git a/Documentation/gcc-plugins.txt b/Documentation/gcc-plugins.txt index 433eaefb4aa1..8502f24396fb 100644 --- a/Documentation/gcc-plugins.txt +++ b/Documentation/gcc-plugins.txt @@ -1,14 +1,15 @@ +========================= GCC plugin infrastructure ========================= -1. Introduction -=============== +Introduction +============ GCC plugins are loadable modules that provide extra features to the -compiler [1]. They are useful for runtime instrumentation and static analysis. +compiler [1]_. They are useful for runtime instrumentation and static analysis. We can analyse, change and add further code during compilation via -callbacks [2], GIMPLE [3], IPA [4] and RTL passes [5]. +callbacks [2]_, GIMPLE [3]_, IPA [4]_ and RTL passes [5]_. The GCC plugin infrastructure of the kernel supports all gcc versions from 4.5 to 6.0, building out-of-tree modules, cross-compilation and building in a @@ -21,56 +22,61 @@ and versions 4.8+ can only be compiled by a C++ compiler. Currently the GCC plugin infrastructure supports only the x86, arm, arm64 and powerpc architectures. -This infrastructure was ported from grsecurity [6] and PaX [7]. +This infrastructure was ported from grsecurity [6]_ and PaX [7]_. -- -[1] https://gcc.gnu.org/onlinedocs/gccint/Plugins.html -[2] https://gcc.gnu.org/onlinedocs/gccint/Plugin-API.html#Plugin-API -[3] https://gcc.gnu.org/onlinedocs/gccint/GIMPLE.html -[4] https://gcc.gnu.org/onlinedocs/gccint/IPA.html -[5] https://gcc.gnu.org/onlinedocs/gccint/RTL.html -[6] https://grsecurity.net/ -[7] https://pax.grsecurity.net/ +.. [1] https://gcc.gnu.org/onlinedocs/gccint/Plugins.html +.. [2] https://gcc.gnu.org/onlinedocs/gccint/Plugin-API.html#Plugin-API +.. [3] https://gcc.gnu.org/onlinedocs/gccint/GIMPLE.html +.. [4] https://gcc.gnu.org/onlinedocs/gccint/IPA.html +.. [5] https://gcc.gnu.org/onlinedocs/gccint/RTL.html +.. [6] https://grsecurity.net/ +.. [7] https://pax.grsecurity.net/ -2. Files -======== -$(src)/scripts/gcc-plugins +Files +===== + +**$(src)/scripts/gcc-plugins** + This is the directory of the GCC plugins. -$(src)/scripts/gcc-plugins/gcc-common.h +**$(src)/scripts/gcc-plugins/gcc-common.h** + This is a compatibility header for GCC plugins. It should be always included instead of individual gcc headers. -$(src)/scripts/gcc-plugin.sh +**$(src)/scripts/gcc-plugin.sh** + This script checks the availability of the included headers in gcc-common.h and chooses the proper host compiler to build the plugins (gcc-4.7 can be built by either gcc or g++). -$(src)/scripts/gcc-plugins/gcc-generate-gimple-pass.h -$(src)/scripts/gcc-plugins/gcc-generate-ipa-pass.h -$(src)/scripts/gcc-plugins/gcc-generate-simple_ipa-pass.h -$(src)/scripts/gcc-plugins/gcc-generate-rtl-pass.h +**$(src)/scripts/gcc-plugins/gcc-generate-gimple-pass.h, +$(src)/scripts/gcc-plugins/gcc-generate-ipa-pass.h, +$(src)/scripts/gcc-plugins/gcc-generate-simple_ipa-pass.h, +$(src)/scripts/gcc-plugins/gcc-generate-rtl-pass.h** + These headers automatically generate the registration structures for GIMPLE, SIMPLE_IPA, IPA and RTL passes. They support all gcc versions from 4.5 to 6.0. They should be preferred to creating the structures by hand. -3. Usage -======== +Usage +===== You must install the gcc plugin headers for your gcc version, -e.g., on Ubuntu for gcc-4.9: +e.g., on Ubuntu for gcc-4.9:: apt-get install gcc-4.9-plugin-dev -Enable a GCC plugin based feature in the kernel config: +Enable a GCC plugin based feature in the kernel config:: CONFIG_GCC_PLUGIN_CYC_COMPLEXITY = y -To compile only the plugin(s): +To compile only the plugin(s):: make gcc-plugins -- 2.9.4
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| From | Kees Cook <keescook@google.com> |
|---|---|
| Date | 2017-05-24 19:40 +0200 |
| Subject | Re: [PATCH 23/31] gcc-plugins.txt: standardize document format |
| Message-ID | <tKIqm-5iH-11@gated-at.bofh.it> |
| In reply to | #1645095 |
On Thu, May 18, 2017 at 6:22 PM, Mauro Carvalho Chehab <mchehab@s-opensource.com> wrote: > Each text file under Documentation follows a different > format. Some doesn't even have titles! > > Change its representation to follow the adopted standard, > using ReST markups for it to be parseable by Sphinx: > > - promote main title; > - use the right markup for footnotes; > - use bold markup for files name; > - identify literal blocks; > - add blank lines to avoid Sphinx to complain; > - remove numeration from titles. > > Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> Acked-by: Kees Cook <keescook@chromium.org> This should probably get moved under "Kernel API documentation" but may need a new sub-category, maybe "instrumentation"? Things like KASan could be put under that too. -Kees -- Kees Cook Pixel Security
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