Commit-ID: 8f62c883222c9e3c06d60b5e55e307a3d1f18257
Gitweb: http://git.kernel.org/tip/8f62c883222c9e3c06d60b5e55e307a3d1f18257
Author: Dave Hansen <[email protected]>
AuthorDate: Fri, 12 Feb 2016 13:02:10 -0800
Committer: Ingo Molnar <[email protected]>
CommitDate: Thu, 18 Feb 2016 09:31:51 +0100
x86/mm/pkeys: Add arch-specific VMA protection bits
Lots of things seem to do:
vma->vm_page_prot = vm_get_page_prot(flags);
and the ptes get created right from things we pull out
of ->vm_page_prot. So it is very convenient if we can
store the protection key in flags and vm_page_prot, just
like the existing permission bits (_PAGE_RW/PRESENT). It
greatly reduces the amount of plumbing and arch-specific
hacking we have to do in generic code.
This also takes the new PROT_PKEY{0,1,2,3} flags and
turns *those* in to VM_ flags for vma->vm_flags.
The protection key values are stored in 4 places:
1. "prot" argument to system calls
2. vma->vm_flags, filled from the mmap "prot"
3. vma->vm_page prot, filled from vma->vm_flags
4. the PTE itself.
The pseudocode for these for steps are as follows:
mmap(PROT_PKEY*)
vma->vm_flags = ... | arch_calc_vm_prot_bits(mmap_prot);
vma->vm_page_prot = ... | arch_vm_get_page_prot(vma->vm_flags);
pte = pfn | vma->vm_page_prot
Note that this provides a new definitions for x86:
arch_vm_get_page_prot()
Signed-off-by: Dave Hansen <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
arch/x86/include/asm/mmu_context.h | 11 +++++++++++
arch/x86/include/asm/pgtable_types.h | 12 ++++++++++--
arch/x86/include/uapi/asm/mman.h | 16 ++++++++++++++++
include/linux/mm.h | 7 +++++++
4 files changed, 44 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/mmu_context.h
b/arch/x86/include/asm/mmu_context.h
index bfd9b2a..94c4c8b 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -275,4 +275,15 @@ static inline void arch_unmap(struct mm_struct *mm, struct
vm_area_struct *vma,
mpx_notify_unmap(mm, vma, start, end);
}
+static inline int vma_pkey(struct vm_area_struct *vma)
+{
+ u16 pkey = 0;
+#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
+ unsigned long vma_pkey_mask = VM_PKEY_BIT0 | VM_PKEY_BIT1 |
+ VM_PKEY_BIT2 | VM_PKEY_BIT3;
+ pkey = (vma->vm_flags & vma_pkey_mask) >> VM_PKEY_SHIFT;
+#endif
+ return pkey;
+}
+
#endif /* _ASM_X86_MMU_CONTEXT_H */
diff --git a/arch/x86/include/asm/pgtable_types.h
b/arch/x86/include/asm/pgtable_types.h
index cae10ba..8c35cf0 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -115,7 +115,12 @@
#define _KERNPG_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | \
_PAGE_DIRTY)
-/* Set of bits not changed in pte_modify */
+/*
+ * Set of bits not changed in pte_modify. The pte's
+ * protection key is treated like _PAGE_RW, for
+ * instance, and is *not* included in this mask since
+ * pte_modify() does modify it.
+ */
#define _PAGE_CHG_MASK (PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT | \
_PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY | \
_PAGE_SOFT_DIRTY)
@@ -231,7 +236,10 @@ enum page_cache_mode {
/* Extracts the PFN from a (pte|pmd|pud|pgd)val_t of a 4KB page */
#define PTE_PFN_MASK ((pteval_t)PHYSICAL_PAGE_MASK)
-/* Extracts the flags from a (pte|pmd|pud|pgd)val_t of a 4KB page */
+/*
+ * Extracts the flags from a (pte|pmd|pud|pgd)val_t
+ * This includes the protection key value.
+ */
#define PTE_FLAGS_MASK (~PTE_PFN_MASK)
typedef struct pgprot { pgprotval_t pgprot; } pgprot_t;
diff --git a/arch/x86/include/uapi/asm/mman.h b/arch/x86/include/uapi/asm/mman.h
index 513b05f..e8562e0 100644
--- a/arch/x86/include/uapi/asm/mman.h
+++ b/arch/x86/include/uapi/asm/mman.h
@@ -6,6 +6,22 @@
#define MAP_HUGE_2MB (21 << MAP_HUGE_SHIFT)
#define MAP_HUGE_1GB (30 << MAP_HUGE_SHIFT)
+#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
+/*
+ * Take the 4 protection key bits out of the vma->vm_flags
+ * value and turn them in to the bits that we can put in
+ * to a pte.
+ *
+ * Only override these if Protection Keys are available
+ * (which is only on 64-bit).
+ */
+#define arch_vm_get_page_prot(vm_flags) __pgprot( \
+ ((vm_flags) & VM_PKEY_BIT0 ? _PAGE_PKEY_BIT0 : 0) | \
+ ((vm_flags) & VM_PKEY_BIT1 ? _PAGE_PKEY_BIT1 : 0) | \
+ ((vm_flags) & VM_PKEY_BIT2 ? _PAGE_PKEY_BIT2 : 0) | \
+ ((vm_flags) & VM_PKEY_BIT3 ? _PAGE_PKEY_BIT3 : 0))
+#endif
+
#include <asm-generic/mman.h>
#endif /* _ASM_X86_MMAN_H */
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 54d173b..3056369 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -183,6 +183,13 @@ extern unsigned int kobjsize(const void *objp);
#if defined(CONFIG_X86)
# define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at
once (x86) */
+#if defined (CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS)
+# define VM_PKEY_SHIFT VM_HIGH_ARCH_BIT_0
+# define VM_PKEY_BIT0 VM_HIGH_ARCH_0 /* A protection key is a 4-bit value */
+# define VM_PKEY_BIT1 VM_HIGH_ARCH_1
+# define VM_PKEY_BIT2 VM_HIGH_ARCH_2
+# define VM_PKEY_BIT3 VM_HIGH_ARCH_3
+#endif
#elif defined(CONFIG_PPC)
# define VM_SAO VM_ARCH_1 /* Strong Access Ordering
(powerpc) */
#elif defined(CONFIG_PARISC)
