From 0e181bb58143cb4a2e8f01c281b0816cd0e4798e Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Wed, 15 Jul 2015 10:29:34 -0700 Subject: [PATCH] x86/nmi/64: Remove asm code that saves CR2 Now that do_nmi saves CR2, we don't need to save it in asm. Signed-off-by: Andy Lutomirski Reviewed-by: Steven Rostedt Acked-by: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: stable@vger.kernel.org Signed-off-by: Ingo Molnar --- arch/x86/entry/entry_64.S | 17 ----------------- 1 file changed, 17 deletions(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 3bb2c4302df1..062feb4eb478 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1415,28 +1415,11 @@ end_repeat_nmi: */ call paranoid_entry - /* - * 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: -- 2.20.1