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| author | Dave Hansen | 2016-02-12 22:02:24 +0100 |
|---|---|---|
| committer | Ingo Molnar | 2016-02-18 19:46:29 +0100 |
| commit | d61172b4b695b821388cdb6088a41d431bcbb93b (patch) | |
| tree | 9e5be0e34ec5e63fd4b728db65a601bd9b904654 /include/linux/mm.h | |
| parent | x86/mm/pkeys: Optimize fault handling in access_error() (diff) | |
| download | kernel-qcow2-linux-d61172b4b695b821388cdb6088a41d431bcbb93b.tar.gz kernel-qcow2-linux-d61172b4b695b821388cdb6088a41d431bcbb93b.tar.xz kernel-qcow2-linux-d61172b4b695b821388cdb6088a41d431bcbb93b.zip | |
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 'include/linux/mm.h')
| -rw-r--r-- | include/linux/mm.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 2aaa0f0d67ea..7955c3eb83db 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -252,6 +252,7 @@ extern pgprot_t protection_map[16]; #define FAULT_FLAG_TRIED 0x20 /* Second try */ #define FAULT_FLAG_USER 0x40 /* The fault originated in userspace */ #define FAULT_FLAG_REMOTE 0x80 /* faulting for non current tsk/mm */ +#define FAULT_FLAG_INSTRUCTION 0x100 /* The fault was during an instruction fetch */ /* * vm_fault is filled by the the pagefault handler and passed to the vma's |