Commit 94ad8474 authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
Browse files

[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: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 1c173409
......@@ -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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