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authorDave Hansen <dave.hansen@linux.intel.com>2016-02-12 13:02:24 -0800
committerIngo Molnar <mingo@kernel.org>2016-02-18 19:46:29 +0100
commitd61172b4b695b821388cdb6088a41d431bcbb93b (patch)
tree9e5be0e34ec5e63fd4b728db65a601bd9b904654 /mm/memory.c
parent07f146f53e8de826e4afa3a88ea65bdb13c24959 (diff)
downloadlinux-d61172b4b695b821388cdb6088a41d431bcbb93b.tar.bz2
mm/core, x86/mm/pkeys: Differentiate instruction fetches
As discussed earlier, we attempt to enforce protection keys in software. However, the code checks all faults to ensure that they are not violating protection key permissions. It was assumed that all faults are either write faults where we check PKRU[key].WD (write disable) or read faults where we check the AD (access disable) bit. But, there is a third category of faults for protection keys: instruction faults. Instruction faults never run afoul of protection keys because they do not affect instruction fetches. So, plumb the PF_INSTR bit down in to the arch_vma_access_permitted() function where we do the protection key checks. We also add a new FAULT_FLAG_INSTRUCTION. This is because handle_mm_fault() is not passed the architecture-specific error_code where we keep PF_INSTR, so we need to encode the instruction fetch information in to the arch-generic fault flags. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave@sr71.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20160212210224.96928009@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 76c44e5dffa2..99e9f928264a 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3380,6 +3380,7 @@ static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
pte_t *pte;
if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE,
+ flags & FAULT_FLAG_INSTRUCTION,
flags & FAULT_FLAG_REMOTE))
return VM_FAULT_SIGSEGV;