From: "Andi Kleen" <[email protected]>
They are rumoured to be much more reliable than the RIP in the stack frame on
P4s.
This is a borderline case because the code is very simple. Please note there
are no plans to add support for all the MCE register MSRs.
Cc: <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andi Kleen <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---
25-akpm/arch/x86_64/kernel/mce.c | 30 ++++++++++++++++++++++--------
1 files changed, 22 insertions(+), 8 deletions(-)
diff -puN arch/x86_64/kernel/mce.c~x86_64-use-the-extended-rip-msr-for-machine-check arch/x86_64/kernel/mce.c
--- 25/arch/x86_64/kernel/mce.c~x86_64-use-the-extended-rip-msr-for-machine-check 2005-04-12 03:21:24.452419568 -0700
+++ 25-akpm/arch/x86_64/kernel/mce.c 2005-04-12 03:21:24.455419112 -0700
@@ -33,6 +33,7 @@ static int banks;
static unsigned long bank[NR_BANKS] = { [0 ... NR_BANKS-1] = ~0UL };
static unsigned long console_logged;
static int notify_user;
+static int rip_msr;
/*
* Lockless MCE logging infrastructure.
@@ -124,6 +125,23 @@ static int mce_available(struct cpuinfo_
test_bit(X86_FEATURE_MCA, &c->x86_capability);
}
+static inline void mce_get_rip(struct mce *m, struct pt_regs *regs)
+{
+ if (regs && (m->mcgstatus & MCG_STATUS_RIPV)) {
+ m->rip = regs->rip;
+ m->cs = regs->cs;
+ } else {
+ m->rip = 0;
+ m->cs = 0;
+ }
+ if (rip_msr) {
+ /* Assume the RIP in the MSR is exact. Is this true? */
+ m->mcgstatus |= MCG_STATUS_EIPV;
+ rdmsrl(rip_msr, m->rip);
+ m->cs = 0;
+ }
+}
+
/*
* The actual machine check handler
*/
@@ -176,14 +194,7 @@ void do_machine_check(struct pt_regs * r
if (m.status & MCI_STATUS_ADDRV)
rdmsrl(MSR_IA32_MC0_ADDR + i*4, m.addr);
- if (regs && (m.mcgstatus & MCG_STATUS_RIPV)) {
- m.rip = regs->rip;
- m.cs = regs->cs;
- } else {
- m.rip = 0;
- m.cs = 0;
- }
-
+ mce_get_rip(&m, regs);
if (error_code != -1)
rdtscll(m.tsc);
wrmsrl(MSR_IA32_MC0_STATUS + i*4, 0);
@@ -296,6 +307,9 @@ static void mce_init(void *dummy)
printk(KERN_INFO "MCE: warning: using only %d banks\n", banks);
banks = NR_BANKS;
}
+ /* Use accurate RIP reporting if available. */
+ if ((cap & (1<<9)) && ((cap >> 16) & 0xff) >= 9)
+ rip_msr = MSR_IA32_MCG_EIP;
/* Log the machine checks left over from the previous reset.
This also clears all registers */
_
-
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