From 94ad84740fb3fe6c2112e60bc71a256c2815479d Mon Sep 17 00:00:00 2001
From: Andi Kleen <ak@suse.de>
Date: Sat, 16 Apr 2005 15:25:09 -0700
Subject: [PATCH] [PATCH] x86_64: Use the extended RIP MSR for machine check
reporting if available.
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: <venkatesh.pallipadi@intel.com>
Cc: <racing.guo@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
arch/x86_64/kernel/mce.c | 30 ++++++++++++++++++++++--------
1 file changed, 22 insertions(+), 8 deletions(-)
diff --git a/arch/x86_64/kernel/mce.c b/arch/x86_64/kernel/mce.c
index 86f9fd85016a3..6ca066424deed 100644
--- a/arch/x86_64/kernel/mce.c
+++ b/arch/x86_64/kernel/mce.c
@@ -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_x86 *c)
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 * regs, long error_code)
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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