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Groups > linux.kernel > #1207805
| From | Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 4.1 33/84] x86/nmi/64: Remove asm code that saves CR2 |
| Date | 2015-08-14 20:20 +0200 |
| Message-ID | <pXrKc-1ru-87@gated-at.bofh.it> (permalink) |
| References | <pXrh7-Cx-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
4.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andy Lutomirski <luto@kernel.org> commit 0e181bb58143cb4a2e8f01c281b0816cd0e4798e upstream. Now that do_nmi saves CR2, we don't need to save it in asm. Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Borislav Petkov <bp@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- arch/x86/kernel/entry_64.S | 18 ------------------ 1 file changed, 18 deletions(-) --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -1603,29 +1603,11 @@ end_repeat_nmi: call paranoid_entry 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: -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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[PATCH 4.1 33/84] x86/nmi/64: Remove asm code that saves CR2 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-08-14 20:20 +0200
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