From: "Andi Kleen" 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: Cc: Signed-off-by: Andi Kleen Signed-off-by: Andrew Morton --- 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 Thu Apr 7 15:11:09 2005 +++ 25-akpm/arch/x86_64/kernel/mce.c Thu Apr 7 15:11:09 2005 @@ -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 */ _