4 files changed, 11 insertions, 36 deletions

diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h
index 32c6e17b960b..5522273a3ad8 100644
--- a/arch/x86/include/asm/mce.h
+++ b/arch/x86/include/asm/mce.h
@@ -120,8 +120,6 @@ extern void mcheck_init(struct cpuinfo_x86 *c);
 #else
 #define mcheck_init(c) do { } while (0)
 #endif
-extern void stop_mce(void);
-extern void restart_mce(void);
 
 #endif /* __KERNEL__ */
 #endif /* _ASM_X86_MCE_H */
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index a84ac7b570e6..5b8394a3a6b2 100644
--- 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
 }
 
 /**
diff --git a/arch/x86/kernel/cpu/mcheck/mce_32.c b/arch/x86/kernel/cpu/mcheck/mce_32.c
index dfaebce3633e..3552119b091d 100644
--- a/arch/x86/kernel/cpu/mcheck/mce_32.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_32.c
@@ -60,20 +60,6 @@ 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;
diff --git a/arch/x86/kernel/cpu/mcheck/mce_64.c b/arch/x86/kernel/cpu/mcheck/mce_64.c
index 5ed80991ab9e..25ccdbec86e2 100644
--- a/arch/x86/kernel/cpu/mcheck/mce_64.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_64.c
@@ -680,20 +680,6 @@ static struct miscdevice mce_log_device = {
         &mce_chrdev_ops,
 };
 
-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);
-}
-
 /*
  * Old style boot options parsing. Only for compatibility.
  */