From: Tony Luck Date: Thu, 19 Jul 2012 18:28:46 +0000 (-0700) Subject: x86/mce: Add quirk for instruction recovery on Sandy Bridge processors X-Git-Tag: firefly_0821_release~3680^2~2249^2~2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=61b0fccd7f114573f973dfe25d864608822dc09e;p=firefly-linux-kernel-4.4.55.git x86/mce: Add quirk for instruction recovery on Sandy Bridge processors Sandy Bridge processors follow the SDM (Vol 3B, Table 15-20) and set both the RIPV and EIPV bits in the MCG_STATUS register to zero for machine checks during instruction fetch. This is more than a little counter-intuitive and means that Linux cannot recover from these errors. Rather than insert special case code at several places in mce.c and mce-severity.c, we pretend the EIPV bit was set for just this case early in processing the machine check. Acked-by: Borislav Petkov Signed-off-by: Tony Luck Cc: Chen Gong Cc: Huang Ying Cc: Hidetoshi Seto Link: http://lkml.kernel.org/r/180a06f3f357cf9f78259ae443a082b14a29535b.1343078495.git.tony.luck@intel.com Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 5a5a5dc1ff15..8cf60e29790a 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -105,6 +105,8 @@ DEFINE_PER_CPU(mce_banks_t, mce_poll_banks) = { static DEFINE_PER_CPU(struct work_struct, mce_work); +static void (*quirk_no_way_out)(int bank, struct mce *m, struct pt_regs *regs); + /* * CPU/chipset specific EDAC code can register a notifier call here to print * MCE errors in a human-readable form. @@ -652,14 +654,18 @@ EXPORT_SYMBOL_GPL(machine_check_poll); * Do a quick check if any of the events requires a panic. * This decides if we keep the events around or clear them. */ -static int mce_no_way_out(struct mce *m, char **msg, unsigned long *validp) +static int mce_no_way_out(struct mce *m, char **msg, unsigned long *validp, + struct pt_regs *regs) { int i, ret = 0; for (i = 0; i < banks; i++) { m->status = mce_rdmsrl(MSR_IA32_MCx_STATUS(i)); - if (m->status & MCI_STATUS_VAL) + if (m->status & MCI_STATUS_VAL) { __set_bit(i, validp); + if (quirk_no_way_out) + quirk_no_way_out(i, m, regs); + } if (mce_severity(m, tolerant, msg) >= MCE_PANIC_SEVERITY) ret = 1; } @@ -1042,7 +1048,7 @@ void do_machine_check(struct pt_regs *regs, long error_code) *final = m; memset(valid_banks, 0, sizeof(valid_banks)); - no_way_out = mce_no_way_out(&m, &msg, valid_banks); + no_way_out = mce_no_way_out(&m, &msg, valid_banks, regs); barrier(); @@ -1418,6 +1424,34 @@ static void __mcheck_cpu_init_generic(void) } } +/* + * During IFU recovery Sandy Bridge -EP4S processors set the RIPV and + * EIPV bits in MCG_STATUS to zero on the affected logical processor (SDM + * Vol 3B Table 15-20). But this confuses both the code that determines + * whether the machine check occurred in kernel or user mode, and also + * the severity assessment code. Pretend that EIPV was set, and take the + * ip/cs values from the pt_regs that mce_gather_info() ignored earlier. + */ +static void quirk_sandybridge_ifu(int bank, struct mce *m, struct pt_regs *regs) +{ + if (bank != 0) + return; + if ((m->mcgstatus & (MCG_STATUS_EIPV|MCG_STATUS_RIPV)) != 0) + return; + if ((m->status & (MCI_STATUS_OVER|MCI_STATUS_UC| + MCI_STATUS_EN|MCI_STATUS_MISCV|MCI_STATUS_ADDRV| + MCI_STATUS_PCC|MCI_STATUS_S|MCI_STATUS_AR| + MCACOD)) != + (MCI_STATUS_UC|MCI_STATUS_EN| + MCI_STATUS_MISCV|MCI_STATUS_ADDRV|MCI_STATUS_S| + MCI_STATUS_AR|MCACOD_INSTR)) + return; + + m->mcgstatus |= MCG_STATUS_EIPV; + m->ip = regs->ip; + m->cs = regs->cs; +} + /* Add per CPU specific workarounds here */ static int __cpuinit __mcheck_cpu_apply_quirks(struct cpuinfo_x86 *c) { @@ -1515,6 +1549,9 @@ static int __cpuinit __mcheck_cpu_apply_quirks(struct cpuinfo_x86 *c) */ if (c->x86 == 6 && c->x86_model <= 13 && mce_bootlog < 0) mce_bootlog = 0; + + if (c->x86 == 6 && c->x86_model == 45) + quirk_no_way_out = quirk_sandybridge_ifu; } if (monarch_timeout < 0) monarch_timeout = 0;