x86, mce: Improve timeout error messages

There are four different possible types of timeouts.  Distinguish
them in the logs to help debug them.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/0fa6d2653a54a01c48b43a3583caf950ea99606e.1419178397.git.luto@amacapital.net
Signed-off-by: Borislav Petkov <bp@suse.de>

1 files changed, 11 insertions, 8 deletions

diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index d2c611699cd9..323e02c658af 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -311,7 +311,7 @@ static void wait_for_panic(void)
         panic("Panicing machine check CPU died");
 }
 
-static void mce_panic(char *msg, struct mce *final, char *exp)
+static void mce_panic(const char *msg, struct mce *final, char *exp)
 {
         int i, apei_err = 0;
 
@@ -735,7 +735,7 @@ static atomic_t mce_callin;
 /*
  * Check if a timeout waiting for other CPUs happened.
  */
-static int mce_timed_out(u64 *t)
+static int mce_timed_out(u64 *t, const char *msg)
 {
         /*
          * The others already did panic for some reason.
@@ -750,8 +750,7 @@ static int mce_timed_out(u64 *t)
                 goto out;
         if ((s64)*t < SPINUNIT) {
                 if (mca_cfg.tolerant <= 1)
-                        mce_panic("Timeout synchronizing machine check over CPUs",
-                                  NULL, NULL);
+                        mce_panic(msg, NULL, NULL);
                 cpu_missing = 1;
                 return 1;
         }
@@ -867,7 +866,8 @@ static int mce_start(int *no_way_out)
          * Wait for everyone.
          */
         while (atomic_read(&mce_callin) != cpus) {
-                if (mce_timed_out(&timeout)) {
+                if (mce_timed_out(&timeout,
+                                  "Timeout: Not all CPUs entered broadcast exception handler")) {
                         atomic_set(&global_nwo, 0);
                         return -1;
                 }
@@ -892,7 +892,8 @@ static int mce_start(int *no_way_out)
                  * only seen by one CPU before cleared, avoiding duplicates.
                  */
                 while (atomic_read(&mce_executing) < order) {
-                        if (mce_timed_out(&timeout)) {
+                        if (mce_timed_out(&timeout,
+                                          "Timeout: Subject CPUs unable to finish machine check processing")) {
                                 atomic_set(&global_nwo, 0);
                                 return -1;
                         }
@@ -936,7 +937,8 @@ static int mce_end(int order)
                  * loops.
                  */
                 while (atomic_read(&mce_executing) <= cpus) {
-                        if (mce_timed_out(&timeout))
+                        if (mce_timed_out(&timeout,
+                                          "Timeout: Monarch CPU unable to finish machine check processing"))
                                 goto reset;
                         ndelay(SPINUNIT);
                 }
@@ -949,7 +951,8 @@ static int mce_end(int order)
                  * Subject: Wait for Monarch to finish.
                  */
                 while (atomic_read(&mce_executing) != 0) {
-                        if (mce_timed_out(&timeout))
+                        if (mce_timed_out(&timeout,
+                                          "Timeout: Monarch CPU did not finish machine check processing"))
                                 goto reset;
                         ndelay(SPINUNIT);
                 }