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Commit 0e181bb5 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
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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: default avatarAndy Lutomirski <luto@kernel.org>
Reviewed-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Acked-by: default avatarBorislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 9d050416

arch/x86/entry/entry_64.S

+0 −17
Original line number Diff line number Diff line
@@ -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: