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authorAndy Lutomirski <luto@kernel.org>2015-07-15 10:29:34 -0700
committerJiri Slaby <jslaby@suse.cz>2015-08-25 16:56:58 +0200
commit3682103fe7e9170cfb806b7ec9dcb3008db51443 (patch)
treeb4d2a1ecb11657cc403c94214cf316c4bad3b594 /arch
parent012ace6161d7461c2693aa3023c8c8abd210c882 (diff)
downloadlwn-3682103fe7e9170cfb806b7ec9dcb3008db51443.tar.gz
lwn-3682103fe7e9170cfb806b7ec9dcb3008db51443.zip
x86/nmi/64: Remove asm code that saves CR2
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: Jiri Slaby <jslaby@suse.cz>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/entry_64.S18
1 files changed, 0 insertions, 18 deletions
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 7b22af265d12..fd27e5b86d7b 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -1876,29 +1876,11 @@ 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: