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| author | Andi Kleen <ak@suse.de> | 2007-07-22 11:12:32 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-22 11:03:37 -0700 |
| commit | 8f4e956b313dcccbc7be6f10808952345e3b638c (patch) | |
| tree | cc8c93fa1faf5e0b608e3a21330a32bd82fe6f47 /arch/i386/kernel/cpu | |
| parent | 19d36ccdc34f5ed444f8a6af0cbfdb6790eb1177 (diff) | |
| download | op-kernel-dev-8f4e956b313dcccbc7be6f10808952345e3b638c.zip op-kernel-dev-8f4e956b313dcccbc7be6f10808952345e3b638c.tar.gz | |
x86: Stop MCEs and NMIs during code patching
When a machine check or NMI occurs while multiple byte code is patched
the CPU could theoretically see an inconsistent instruction and crash.
Prevent this by temporarily disabling MCEs and returning early in the
NMI handler.
Based on discussion with Mathieu Desnoyers.
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/i386/kernel/cpu')
| -rw-r--r-- | arch/i386/kernel/cpu/mcheck/mce.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/i386/kernel/cpu/mcheck/mce.c b/arch/i386/kernel/cpu/mcheck/mce.c index 56cd485..34c781e 100644 --- a/arch/i386/kernel/cpu/mcheck/mce.c +++ b/arch/i386/kernel/cpu/mcheck/mce.c @@ -60,6 +60,20 @@ void mcheck_init(struct cpuinfo_x86 *c) } } +static unsigned long old_cr4 __initdata; + +void __init stop_mce(void) +{ + old_cr4 = read_cr4(); + clear_in_cr4(X86_CR4_MCE); +} + +void __init restart_mce(void) +{ + if (old_cr4 & X86_CR4_MCE) + set_in_cr4(X86_CR4_MCE); +} + static int __init mcheck_disable(char *str) { mce_disabled = 1; |
