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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-07-22 12:04:44 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-07-22 12:04:44 -0700 |
| commit | 3fad0953a12f92289f1e35f091c4fa09d8e1884e (patch) | |
| tree | fdf5d23d76f03ac06289ee0e8678d4e125083cbb /arch/x86/kernel/entry_64.S | |
| parent | a065de0d257779ed1b8ee6e0c005ad6b1d989cef (diff) | |
| parent | 0fa0e2f02e8edfbdb5f86d1cab0fa6dc0517489f (diff) | |
| download | blackbird-op-linux-3fad0953a12f92289f1e35f091c4fa09d8e1884e.tar.gz blackbird-op-linux-3fad0953a12f92289f1e35f091c4fa09d8e1884e.zip | |
Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull debug-for-linus git tree from Ingo Molnar.
Fix up trivial conflict in arch/x86/kernel/cpu/perf_event_intel.c due to
a printk() having changed to a pr_info() differently in the two branches.
* 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86: Move call to print_modules() out of show_regs()
x86/mm: Mark free_initrd_mem() as __init
x86/microcode: Mark microcode_id[] as __initconst
x86/nmi: Clean up register_nmi_handler() usage
x86: Save cr2 in NMI in case NMIs take a page fault (for i386)
x86: Remove cmpxchg from i386 NMI nesting code
x86: Save cr2 in NMI in case NMIs take a page fault
x86/debug: Add KERN_<LEVEL> to bare printks, convert printks to pr_<level>
Diffstat (limited to 'arch/x86/kernel/entry_64.S')
| -rw-r--r-- | arch/x86/kernel/entry_64.S | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index 7d65133b51be..111f6bbd8b38 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -1758,10 +1758,30 @@ end_repeat_nmi: */ call save_paranoid DEFAULT_FRAME 0 + + /* + * Save off the CR2 register. If we take a page fault in the NMI then + * it could corrupt the CR2 value. If the NMI preempts a page fault + * handler before it was able to read the CR2 register, and then the + * NMI itself takes a page fault, the page fault that was preempted + * will read the information from the NMI page fault and not the + * origin fault. Save it off and restore it if it changes. + * Use the r12 callee-saved register. + */ + movq %cr2, %r12 + /* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */ movq %rsp,%rdi movq $-1,%rsi call do_nmi + + /* Did the NMI take a page fault? Restore cr2 if it did */ + movq %cr2, %rcx + cmpq %rcx, %r12 + je 1f + movq %r12, %cr2 +1: + testl %ebx,%ebx /* swapgs needed? */ jnz nmi_restore nmi_swapgs: |
