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Groups > linux.kernel > #1645089
| From | Mauro Carvalho Chehab <mchehab@s-opensource.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 25/31] hw_random.txt: standardize document format |
| Date | 2017-05-19 03:50 +0200 |
| Message-ID | <tIFdg-3gE-23@gated-at.bofh.it> (permalink) |
| References | <tIETT-39a-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
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
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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
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