x86, mce: don't disable machine checks during code patching

[karo-tx-linux.git] / arch / x86 / kernel / alternative.c

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index a84ac7b570e6bb4582788da74a4c570e28fd65e9..5b8394a3a6b25a20ac49d7c113098385f06e5748 100644 (file)
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -414,9 +414,17 @@ void __init alternative_instructions(void)
           that might execute the to be patched code.
           Other CPUs are not running. */
        stop_nmi();
-#ifdef CONFIG_X86_MCE
-       stop_mce();
-#endif
+
+       /*
+        * Don't stop machine check exceptions while patching.
+        * MCEs only happen when something got corrupted and in this
+        * case we must do something about the corruption.
+        * Ignoring it is worse than a unlikely patching race.
+        * Also machine checks tend to be broadcast and if one CPU
+        * goes into machine check the others follow quickly, so we don't
+        * expect a machine check to cause undue problems during to code
+        * patching.
+        */
 
        apply_alternatives(__alt_instructions, __alt_instructions_end);
 
@@ -456,9 +464,6 @@ void __init alternative_instructions(void)
                                (unsigned long)__smp_locks_end);
 
        restart_nmi();
-#ifdef CONFIG_X86_MCE
-       restart_mce();
-#endif
 }
 
 /**