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| author | H. Peter Anvin <hpa@linux.intel.com> | 2012-09-21 21:43:14 +0200 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2012-09-21 21:45:27 +0200 |
| commit | 40d3cd6695014bf3c44e2ca66b610b18acaf923d (patch) | |
| tree | 535ecc7a30ea16221efbd16fcd1717e8ed4b6183 /arch/x86 | |
| parent | x86, smap: Turn on Supervisor Mode Access Prevention (diff) | |
| download | linux-40d3cd6695014bf3c44e2ca66b610b18acaf923d.tar.xz linux-40d3cd6695014bf3c44e2ca66b610b18acaf923d.zip | |
x86, smap: A page fault due to SMAP is an oops
If we get a page fault due to SMAP, trigger an oops rather than
spinning forever.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1348256595-29119-11-git-send-email-hpa@linux.intel.com
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/mm/fault.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 76dcd9d8e0bc..f2fb75d46b96 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -995,6 +995,17 @@ static int fault_in_kernel_space(unsigned long address) return address >= TASK_SIZE_MAX; } +static inline bool smap_violation(int error_code, struct pt_regs *regs) +{ + if (error_code & PF_USER) + return false; + + if (!user_mode_vm(regs) && (regs->flags & X86_EFLAGS_AC)) + return false; + + return true; +} + /* * This routine handles page faults. It determines the address, * and the problem, and then passes it off to one of the appropriate @@ -1088,6 +1099,13 @@ do_page_fault(struct pt_regs *regs, unsigned long error_code) if (unlikely(error_code & PF_RSVD)) pgtable_bad(regs, error_code, address); + if (static_cpu_has(X86_FEATURE_SMAP)) { + if (unlikely(smap_violation(error_code, regs))) { + bad_area_nosemaphore(regs, error_code, address); + return; + } + } + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); /* |