From: Chen Yucong <slaoub@xxxxxxxxx> dram_ce_error() stems from Boris's patch set. Thanks! Link: http://lkml.org/lkml/2014/7/1/545 Uncorrected no action required (UCNA) - is a UCR error that is not signaled via a machine check exception and, instead, is reported to system software as a corrected machine check error. UCNA errors indicate that some data in the system is corrupted, but the data has not been consumed and the processor state is valid and you may continue execution on this processor. UCNA errors require no action from system software to continue execution. Note that UCNA errors are supported by the processor only when IA32_MCG_CAP[24] (MCG_SER_P) is set. -- Intel SDM Volume 3B Deferred errors are errors that cannot be corrected by hardware, but do not cause an immediate interruption in program flow, loss of data integrity, or corruption of processor state. These errors indicate that data has been corrupted but not consumed. Hardware writes information to the status and address registers in the corresponding bank that identifies the source of the error if deferred errors are enabled for logging. Deferred errors are not reported via machine check exceptions; they can be seen by polling the MCi_STATUS registers. -- ADM64 APM Volume 2 Above two items, both UCNA and Deferred errors belong to detected errors, but they can't be corrected by hardware, and this is very similar to Software Recoverable Action Optional (SRAO) errors. Therefore, we can take some actions that have been used for handling SRAO errors to handle UCNA and Deferred errors. Signed-off-by: Chen Yucong <slaoub@xxxxxxxxx> --- arch/x86/include/asm/mce.h | 4 ++++ arch/x86/kernel/cpu/mcheck/mce.c | 39 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 43 insertions(+) diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h index 958b90f..c9ac7df4 100644 --- a/arch/x86/include/asm/mce.h +++ b/arch/x86/include/asm/mce.h @@ -34,6 +34,10 @@ #define MCI_STATUS_S (1ULL<<56) /* Signaled machine check */ #define MCI_STATUS_AR (1ULL<<55) /* Action required */ +/* AMD-specific bits */ +#define MCI_STATUS_DEFERRED (1ULL<<44) /* declare an uncorrected error */ +#define MCI_STATUS_POISON (1ULL<<43) /* access poisonous data */ + /* * Note that the full MCACOD field of IA32_MCi_STATUS MSR is * bits 15:0. But bit 12 is the 'F' bit, defined for corrected diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 61a9668ce..4030c77 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -575,6 +575,35 @@ static void mce_read_aux(struct mce *m, int i) } } +static bool dram_ce_error(struct mce *m) +{ + struct cpuinfo_x86 *c = &boot_cpu_data; + + if (c->x86_vendor == X86_VENDOR_AMD) { + /* ErrCodeExt[20:16] */ + u8 xec = (m->status >> 16) & 0x1f; + + if (m->status & MCI_STATUS_DEFERRED) + return (xec == 0x0 || xec == 0x8); + } else if (c->x86_vendor == X86_VENDOR_INTEL) { + /* + * SDM Volume 3B - 15.9.2 Compound Error Codes (Table 15-9) + * + * Bit 7 of the MCACOD field of IA32_MCi_STATUS is used for + * indicating a memory error. But we can't just blindly check + * bit 7 because if bit 8 is set, then this is a cache error, + * and if bit 11 is set, then it is a bus/ interconnect error + * - and either way bit 7 just gives more detail on what + * cache/bus/interconnect error happened. Note that we can + * ignore bit 12, as it's the "filter" bit. + */ + if ((m->mcgcap & MCG_SER_P) && (m->status & MCI_STATUS_UC)) + return (m->status & 0xef80) == BIT(7); + } + + return false; +} + DEFINE_PER_CPU(unsigned, mce_poll_count); /* @@ -630,6 +659,16 @@ void machine_check_poll(enum mcp_flags flags, mce_banks_t *b) if (!(flags & MCP_TIMESTAMP)) m.tsc = 0; + + /* + * In the cases where we don't have a valid address after all, + * do not add it into the ring buffer. + */ + if (dram_ce_error(&m) && (m.status & MCI_STATUS_ADDRV)) { + mce_ring_add(m.addr >> PAGE_SHIFT); + mce_schedule_work(); + } + /* * Don't get the IP here because it's unlikely to * have anything to do with the actual error location. -- 1.7.10.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>