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Groups > linux.kernel > #1333127

[PATCH 11/33] x86, pkeys: store protection in high VMA flags

From Dave Hansen <dave@sr71.net>
Newsgroups linux.kernel
Subject [PATCH 11/33] x86, pkeys: store protection in high VMA flags
Date 2016-02-12 22:20 +0100
Message-ID <r1tia-3WT-1@gated-at.bofh.it> (permalink)
References <r1t8t-3TO-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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From: Dave Hansen <dave.hansen@linux.intel.com>

vma->vm_flags is an 'unsigned long', so has space for 32 flags
on 32-bit architectures.  The high 32 bits are unused on 64-bit
platforms.  We've steered away from using the unused high VMA
bits for things because we would have difficulty supporting it
on 32-bit.

Protection Keys are not available in 32-bit mode, so there is
no concern about supporting this feature in 32-bit mode or on
32-bit CPUs.

This patch carves out 4 bits from the high half of
vma->vm_flags and allows architectures to set config option
to make them available.

Sparse complains about these constants unless we explicitly
call them "UL".

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
---

 b/arch/x86/Kconfig   |    1 +
 b/include/linux/mm.h |   11 +++++++++++
 b/mm/Kconfig         |    3 +++
 3 files changed, 15 insertions(+)

diff -puN arch/x86/Kconfig~pkeys-06-eat-high-vma-flags arch/x86/Kconfig
--- a/arch/x86/Kconfig~pkeys-06-eat-high-vma-flags	2016-02-12 10:44:18.494350045 -0800
+++ b/arch/x86/Kconfig	2016-02-12 10:44:18.502350411 -0800
@@ -155,6 +155,7 @@ config X86
 	select VIRT_TO_BUS
 	select X86_DEV_DMA_OPS			if X86_64
 	select X86_FEATURE_NAMES		if PROC_FS
+	select ARCH_USES_HIGH_VMA_FLAGS		if X86_INTEL_MEMORY_PROTECTION_KEYS
 
 config INSTRUCTION_DECODER
 	def_bool y
diff -puN include/linux/mm.h~pkeys-06-eat-high-vma-flags include/linux/mm.h
--- a/include/linux/mm.h~pkeys-06-eat-high-vma-flags	2016-02-12 10:44:18.496350136 -0800
+++ b/include/linux/mm.h	2016-02-12 10:44:18.503350456 -0800
@@ -170,6 +170,17 @@ extern unsigned int kobjsize(const void
 #define VM_NOHUGEPAGE	0x40000000	/* MADV_NOHUGEPAGE marked this vma */
 #define VM_MERGEABLE	0x80000000	/* KSM may merge identical pages */
 
+#ifdef CONFIG_ARCH_USES_HIGH_VMA_FLAGS
+#define VM_HIGH_ARCH_BIT_0	32	/* bit only usable on 64-bit architectures */
+#define VM_HIGH_ARCH_BIT_1	33	/* bit only usable on 64-bit architectures */
+#define VM_HIGH_ARCH_BIT_2	34	/* bit only usable on 64-bit architectures */
+#define VM_HIGH_ARCH_BIT_3	35	/* bit only usable on 64-bit architectures */
+#define VM_HIGH_ARCH_0	BIT(VM_HIGH_ARCH_BIT_0)
+#define VM_HIGH_ARCH_1	BIT(VM_HIGH_ARCH_BIT_1)
+#define VM_HIGH_ARCH_2	BIT(VM_HIGH_ARCH_BIT_2)
+#define VM_HIGH_ARCH_3	BIT(VM_HIGH_ARCH_BIT_3)
+#endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */
+
 #if defined(CONFIG_X86)
 # define VM_PAT		VM_ARCH_1	/* PAT reserves whole VMA at once (x86) */
 #elif defined(CONFIG_PPC)
diff -puN mm/Kconfig~pkeys-06-eat-high-vma-flags mm/Kconfig
--- a/mm/Kconfig~pkeys-06-eat-high-vma-flags	2016-02-12 10:44:18.498350228 -0800
+++ b/mm/Kconfig	2016-02-12 10:44:18.503350456 -0800
@@ -669,3 +669,6 @@ config ZONE_DEVICE
 
 config FRAME_VECTOR
 	bool
+
+config ARCH_USES_HIGH_VMA_FLAGS
+	bool
_

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Thread

[PATCH 00/33] x86: Memory Protection Keys (v10) Dave Hansen <dave@sr71.net> - 2016-02-12 22:10 +0100
  [PATCH 18/33] x86, mm: simplify get_user_pages() PTE bit handling Dave Hansen <dave@sr71.net> - 2016-02-12 22:10 +0100
    [tip:mm/pkeys] x86/mm/gup: Simplify get_user_pages()   PTE bit handling tip-bot for Dave Hansen <tipbot@zytor.com> - 2016-02-18 21:30 +0100
  [PATCH 23/33] x86, pkeys: dump PKRU with other kernel registers Dave Hansen <dave@sr71.net> - 2016-02-12 22:10 +0100
    [tip:mm/pkeys] x86/mm/pkeys:   Dump PKRU with other kernel registers tip-bot for Dave Hansen <tipbot@zytor.com> - 2016-02-18 21:30 +0100
  [PATCH 30/33] x86, fpu: allow setting of XSAVE state Dave Hansen <dave@sr71.net> - 2016-02-12 22:10 +0100
    [tip:mm/pkeys] x86/fpu: Allow setting of XSAVE state tip-bot for Dave Hansen <tipbot@zytor.com> - 2016-02-18 21:30 +0100
  [PATCH 03/33] mm, gup: switch callers of get_user_pages() to not pass tsk/mm Dave Hansen <dave@sr71.net> - 2016-02-12 22:10 +0100
    [tip:mm/pkeys] mm/gup: Switch all callers of get_user_pages()   to not pass tsk/mm tip-bot for Dave Hansen <tipbot@zytor.com> - 2016-02-18 21:20 +0100
  [PATCH 19/33] x86, pkeys: check VMAs and PTEs for protection keys Dave Hansen <dave@sr71.net> - 2016-02-12 22:10 +0100
    [tip:mm/pkeys] mm/gup, x86/mm/pkeys:   Check VMAs and PTEs for protection keys tip-bot for Dave Hansen <tipbot@zytor.com> - 2016-02-18 21:30 +0100
  [PATCH 26/33] x86, pkeys: actually enable Memory Protection Keys in CPU Dave Hansen <dave@sr71.net> - 2016-02-12 22:10 +0100
    [tip:mm/pkeys] x86/mm/pkeys:   Actually enable Memory Protection Keys in the CPU tip-bot for Dave Hansen <tipbot@zytor.com> - 2016-02-18 21:30 +0100
  [PATCH 07/33] x86, pkeys: define new CR4 bit Dave Hansen <dave@sr71.net> - 2016-02-12 22:10 +0100
    [tip:mm/pkeys] x86/cpu, x86/mm/pkeys: Define new CR4 bit tip-bot for Dave Hansen <tipbot@zytor.com> - 2016-02-18 21:20 +0100
  [PATCH 13/33] x86, pkeys: pass VMA down in to fault signal generation code Dave Hansen <dave@sr71.net> - 2016-02-12 22:10 +0100
    [tip:mm/pkeys] x86/mm/pkeys:   Pass VMA down in to fault signal generation code tip-bot for Dave Hansen <tipbot@zytor.com> - 2016-02-18 21:30 +0100
  [PATCH 11/33] x86, pkeys: store protection in high VMA flags Dave Hansen <dave@sr71.net> - 2016-02-12 22:20 +0100
    [tip:mm/pkeys] mm/core, x86/mm/pkeys:   Store protection bits in high VMA flags tip-bot for Dave Hansen <tipbot@zytor.com> - 2016-02-18 21:30 +0100
  [PATCH 10/33] x86, pkeys: new page fault error code bit: PF_PK Dave Hansen <dave@sr71.net> - 2016-02-12 22:20 +0100
    [tip:mm/pkeys] x86/mm/pkeys: Add new 'PF_PK'   page fault error code bit tip-bot for Dave Hansen <tipbot@zytor.com> - 2016-02-18 21:20 +0100
  [PATCH 09/33] x86, pkeys: PTE bits for storing protection key Dave Hansen <dave@sr71.net> - 2016-02-12 22:20 +0100
    [tip:mm/pkeys] x86/mm/pkeys:   Add PTE bits for storing protection key tip-bot for Dave Hansen <tipbot@zytor.com> - 2016-02-18 21:20 +0100
  [PATCH 06/33] x86, pkeys: cpuid bit definition Dave Hansen <dave@sr71.net> - 2016-02-12 22:20 +0100
    [tip:mm/pkeys] x86/cpufeature, x86/mm/pkeys:   Add protection keys related CPUID definitions tip-bot for Dave Hansen <tipbot@zytor.com> - 2016-02-18 21:20 +0100
  [PATCH 02/33] mm: overload get_user_pages() functions Dave Hansen <dave@sr71.net> - 2016-02-12 22:20 +0100
    Re: [PATCH 02/33] mm: overload get_user_pages() functions Ingo Molnar <mingo@kernel.org> - 2016-02-16 09:40 +0100
      Re: [PATCH 02/33] mm: overload get_user_pages() functions Dave Hansen <dave@sr71.net> - 2016-02-17 19:20 +0100
    [tip:mm/pkeys] mm/gup: Overload get_user_pages() functions tip-bot for Dave Hansen <tipbot@zytor.com> - 2016-02-18 21:20 +0100
  [PATCH 01/33] mm: introduce get_user_pages_remote() Dave Hansen <dave@sr71.net> - 2016-02-12 22:20 +0100
    Re: [PATCH 01/33] mm: introduce get_user_pages_remote() Balbir Singh <bsingharora@gmail.com> - 2016-02-15 07:10 +0100
      Re: [PATCH 01/33] mm: introduce get_user_pages_remote() Dave Hansen <dave@sr71.net> - 2016-02-15 17:30 +0100
    Re: [PATCH 01/33] mm: introduce get_user_pages_remote() Srikar Dronamraju <srikar@linux.vnet.ibm.com> - 2016-02-15 07:20 +0100
    [tip:x86/pkeys] mm/gup: Introduce get_user_pages_remote() tip-bot for Dave Hansen <tipbot@zytor.com> - 2016-02-16 13:20 +0100
      Re: [tip:x86/pkeys] mm/gup: Introduce get_user_pages_remote() Konstantin Khlebnikov <koct9i@gmail.com> - 2016-02-20 07:30 +0100
  [PATCH 05/33] x86, pkeys: Add Kconfig option Dave Hansen <dave@sr71.net> - 2016-02-12 22:20 +0100
    [tip:mm/pkeys] x86/mm/pkeys: Add Kconfig option tip-bot for Dave Hansen <tipbot@zytor.com> - 2016-02-18 21:20 +0100
      [PATCH] x86/mm/pkeys: Do not enable them by default Borislav Petkov <bp@alien8.de> - 2016-02-19 12:30 +0100
        Re: [PATCH] x86/mm/pkeys: Do not enable them by default Dave Hansen <dave@sr71.net> - 2016-02-19 18:20 +0100
          Re: [PATCH] x86/mm/pkeys: Do not enable them by default Borislav Petkov <bp@alien8.de> - 2016-02-19 18:30 +0100
            Re: [PATCH] x86/mm/pkeys: Do not enable them by default Dave Hansen <dave@sr71.net> - 2016-02-19 18:50 +0100
              Re: [PATCH] x86/mm/pkeys: Do not enable them by default Borislav Petkov <bp@alien8.de> - 2016-02-19 19:40 +0100
  Re: [PATCH 00/33] x86: Memory Protection Keys (v10) Ingo Molnar <mingo@kernel.org> - 2016-02-16 10:30 +0100

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