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authorAndi Kleen <andi@firstfloor.org>2009-05-27 21:56:54 +0200
committerH. Peter Anvin <hpa@zytor.com>2009-06-03 14:40:39 -0700
commita0189c70e5f17f4253dd7bc575c97469900e23d6 (patch)
treefc9d58a92124812aa0177fcff271f6c33903fafe /arch/x86/kernel/cpu
parentde8a84d85ad8bb46d01d72ebc57030b95075603c (diff)
x86, mce: remove TSC print heuristic
Previously mce_panic used a simple heuristic to avoid printing old so far unreported machine check events on a mce panic. This worked by comparing the TSC value at the start of the machine check handler with the event time stamp and only printing newer ones. This has a couple of issues, in particular on systems where the TSC is not fully synchronized between CPUs it could lose events or print old ones. It is also problematic with full system synchronization as it is added by the next patch. Remove the TSC heuristic and instead replace it with a simple heuristic to print corrected errors first and after that uncorrected errors and finally the worst machine check as determined by the machine check handler. This simplifies the code because there is no need to pass the original TSC value around. Contains fixes from Ying Huang [ Impact: bug fix, cleanup ] Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: Ying Huang <ying.huang@intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/kernel/cpu')
-rw-r--r--arch/x86/kernel/cpu/mcheck/mce.c32
1 files changed, 18 insertions, 14 deletions
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 86806e52fc4..6773610061d 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -158,6 +158,7 @@ void mce_log(struct mce *mce)
mcelog.entry[entry].finished = 1;
wmb();
+ mce->finished = 1;
set_bit(0, &notify_user);
}
@@ -190,23 +191,29 @@ static void print_mce(struct mce *m)
"and contact your hardware vendor\n");
}
-static void mce_panic(char *msg, struct mce *backup, u64 start)
+static void mce_panic(char *msg, struct mce *final)
{
int i;
bust_spinlocks(1);
console_verbose();
+ /* First print corrected ones that are still unlogged */
for (i = 0; i < MCE_LOG_LEN; i++) {
- u64 tsc = mcelog.entry[i].tsc;
-
- if ((s64)(tsc - start) < 0)
+ struct mce *m = &mcelog.entry[i];
+ if ((m->status & MCI_STATUS_VAL) &&
+ !(m->status & MCI_STATUS_UC))
+ print_mce(m);
+ }
+ /* Now print uncorrected but with the final one last */
+ for (i = 0; i < MCE_LOG_LEN; i++) {
+ struct mce *m = &mcelog.entry[i];
+ if (!(m->status & MCI_STATUS_VAL))
continue;
- print_mce(&mcelog.entry[i]);
- if (backup && mcelog.entry[i].tsc == backup->tsc)
- backup = NULL;
+ if (!final || memcmp(m, final, sizeof(struct mce)))
+ print_mce(m);
}
- if (backup)
- print_mce(backup);
+ if (final)
+ print_mce(final);
panic(msg);
}
@@ -362,7 +369,6 @@ void do_machine_check(struct pt_regs *regs, long error_code)
{
struct mce m, panicm;
int panicm_found = 0;
- u64 mcestart = 0;
int i;
/*
* If no_way_out gets set, there is no safe way to recover from this
@@ -394,7 +400,6 @@ void do_machine_check(struct pt_regs *regs, long error_code)
if (!(m.mcgstatus & MCG_STATUS_RIPV))
no_way_out = 1;
- rdtscll(mcestart);
barrier();
for (i = 0; i < banks; i++) {
@@ -478,7 +483,7 @@ void do_machine_check(struct pt_regs *regs, long error_code)
* has not set tolerant to an insane level, give up and die.
*/
if (no_way_out && tolerant < 3)
- mce_panic("Machine check", &panicm, mcestart);
+ mce_panic("Machine check", &panicm);
/*
* If the error seems to be unrecoverable, something should be
@@ -506,8 +511,7 @@ void do_machine_check(struct pt_regs *regs, long error_code)
if (user_space) {
force_sig(SIGBUS, current);
} else if (panic_on_oops || tolerant < 2) {
- mce_panic("Uncorrected machine check",
- &panicm, mcestart);
+ mce_panic("Uncorrected machine check", &panicm);
}
}