# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1264747823 0
# Node ID ebd2495ec073064d5f05754060fdf6ce38b907a3
# Parent 088f1b01d852ebb513f8fb5ed9b457d5f6afe291
x86 mca: Be more careful for printk in MCE context
MCE may happen in printk context, and will cause deadlock if we try to
call printk again in MCE context.
A new level(mce_critical) is added to mce_verbosity for printk in mce
context. This level is only for developer that aware of such issue.
In mce_panic, force console unlock.
Singed-off-by: Jiang, Yunhong <yunhong.jiang@xxxxxxxxx>
---
xen/arch/x86/cpu/mcheck/mce.c | 2 +-
xen/arch/x86/cpu/mcheck/mce.h | 6 ++++--
xen/arch/x86/cpu/mcheck/mce_intel.c | 6 +++---
3 files changed, 8 insertions(+), 6 deletions(-)
diff -r 088f1b01d852 -r ebd2495ec073 xen/arch/x86/cpu/mcheck/mce.c
--- a/xen/arch/x86/cpu/mcheck/mce.c Fri Jan 29 06:49:42 2010 +0000
+++ b/xen/arch/x86/cpu/mcheck/mce.c Fri Jan 29 06:50:23 2010 +0000
@@ -1605,7 +1605,7 @@ void mc_panic(char *s)
void mc_panic(char *s)
{
is_mc_panic = 1;
- console_start_sync();
+ console_force_unlock();
printk("Fatal machine check: %s\n", s);
printk("\n"
"****************************************\n"
diff -r 088f1b01d852 -r ebd2495ec073 xen/arch/x86/cpu/mcheck/mce.h
--- a/xen/arch/x86/cpu/mcheck/mce.h Fri Jan 29 06:49:42 2010 +0000
+++ b/xen/arch/x86/cpu/mcheck/mce.h Fri Jan 29 06:50:23 2010 +0000
@@ -12,8 +12,10 @@
#include "x86_mca.h"
#include "mctelem.h"
-#define MCE_QUIET 0
-#define MCE_VERBOSE 1
+#define MCE_QUIET 0
+#define MCE_VERBOSE 1
+/* !only for developer debug as printk is unsafe in MCE context */
+#define MCE_CRITICAL 2
extern int mce_verbosity;
/* Define the default level of machine check related print.
diff -r 088f1b01d852 -r ebd2495ec073 xen/arch/x86/cpu/mcheck/mce_intel.c
--- a/xen/arch/x86/cpu/mcheck/mce_intel.c Fri Jan 29 06:49:42 2010 +0000
+++ b/xen/arch/x86/cpu/mcheck/mce_intel.c Fri Jan 29 06:50:23 2010 +0000
@@ -687,7 +687,7 @@ static void intel_machine_check(struct c
}
atomic_set(&found_error, 1);
- mce_printk(MCE_VERBOSE, "MCE: clear_bank map %lx on CPU%d\n",
+ mce_printk(MCE_CRITICAL, "MCE: clear_bank map %lx on CPU%d\n",
*((unsigned long*)clear_bank), smp_processor_id());
mcheck_mca_clearbanks(clear_bank);
/* Print MCE error */
@@ -714,13 +714,13 @@ static void intel_machine_check(struct c
/* Clear error finding flags after all cpus finishes above judgement */
mce_barrier_enter(&mce_trap_bar);
if (atomic_read(&found_error)) {
- mce_printk(MCE_VERBOSE, "MCE: Choose one CPU "
+ mce_printk(MCE_CRITICAL, "MCE: Choose one CPU "
"to clear error finding flag\n ");
atomic_set(&found_error, 0);
}
mca_rdmsrl(MSR_IA32_MCG_STATUS, gstatus);
if ((gstatus & MCG_STATUS_MCIP) != 0) {
- mce_printk(MCE_VERBOSE, "MCE: Clear MCIP@ last step");
+ mce_printk(MCE_CRITICAL, "MCE: Clear MCIP@ last step");
mca_wrmsrl(MSR_IA32_MCG_STATUS, gstatus & ~MCG_STATUS_MCIP);
}
mce_barrier_exit(&mce_trap_bar);
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