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[PATCH 09/31] x86, pkeys: store protection in high VMA flags

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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	2016-01-28 15:52:20.189396084 -0800
+++ b/arch/x86/Kconfig	2016-01-28 15:52:20.197396451 -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	2016-01-28 15:52:20.191396176 -0800
+++ b/include/linux/mm.h	2016-01-28 15:52:20.198396497 -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	2016-01-28 15:52:20.193396268 -0800
+++ b/mm/Kconfig	2016-01-28 15:52:20.198396497 -0800
@@ -668,3 +668,6 @@ config ZONE_DEVICE
 
 config FRAME_VECTOR
 	bool
+
+config ARCH_USES_HIGH_VMA_FLAGS
+	bool
_

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[PATCH 00/31] x86: Memory Protection Keys (v9) Dave Hansen <dave@sr71.net> - 2016-01-29 19:20 +0100
  [PATCH 21/31] x86, pkeys: dump PKRU with other kernel registers Dave Hansen <dave@sr71.net> - 2016-01-29 19:20 +0100
  [PATCH 26/31] x86, pkeys: add arch_validate_pkey() Dave Hansen <dave@sr71.net> - 2016-01-29 19:20 +0100
  [PATCH 29/31] x86, pkeys: allow kernel to modify user pkey rights register Dave Hansen <dave@sr71.net> - 2016-01-29 19:20 +0100
  [PATCH 03/31] x86, pkeys: Add Kconfig option Dave Hansen <dave@sr71.net> - 2016-01-29 19:20 +0100
  [PATCH 09/31] x86, pkeys: store protection in high VMA flags Dave Hansen <dave@sr71.net> - 2016-01-29 19:20 +0100
  [PATCH 05/31] x86, pkeys: define new CR4 bit Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 23/31] x86, pkeys: add Kconfig prompt to existing config option Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 12/31] signals, pkeys: notify userspace about protection key faults Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 24/31] x86, pkeys: actually enable Memory Protection Keys in CPU Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 15/31] mm: factor out VMA fault permission checking Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 20/31] x86, pkeys: differentiate instruction fetches Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 18/31] mm: do not enforce PKEY permissions on "foreign" mm access Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 08/31] x86, pkeys: new page fault error code bit: PF_PK Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 14/31] x86, pkeys: add functions to fetch PKRU Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 04/31] x86, pkeys: cpuid bit definition Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 10/31] x86, pkeys: arch-specific protection bits Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 13/31] x86, pkeys: fill in pkey field in siginfo Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 25/31] mm, multi-arch: pass a protection key in to calc_vm_flag_bits() Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 17/31] x86, pkeys: check VMAs and PTEs for protection keys Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 07/31] x86, pkeys: PTE bits for storing protection key Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 02/31] x86, fpu: add placeholder for Processor Trace XSAVE state Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 16/31] x86, mm: simplify get_user_pages() PTE bit handling Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 11/31] x86, pkeys: pass VMA down in to fault signal generation code Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 22/31] x86, pkeys: dump pkey from VMA in /proc/pid/smaps Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
    Re: [PATCH 22/31] x86, pkeys: dump pkey from VMA in /proc/pid/smaps Vlastimil Babka <vbabka@suse.cz> - 2016-02-02 17:20 +0100
      Re: [PATCH 22/31] x86, pkeys: dump pkey from VMA in /proc/pid/smaps Dave Hansen <dave@sr71.net> - 2016-02-02 20:10 +0100
  [PATCH 06/31] x86, pkeys: add PKRU xsave fields and data structure(s) Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100

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