diff options
Diffstat (limited to 'arch/x86_64/kernel/mce.c')
| -rw-r--r-- | arch/x86_64/kernel/mce.c | 70 |
1 files changed, 49 insertions, 21 deletions
diff --git a/arch/x86_64/kernel/mce.c b/arch/x86_64/kernel/mce.c index 3b267c91bb0c..69541db5ff2c 100644 --- a/arch/x86_64/kernel/mce.c +++ b/arch/x86_64/kernel/mce.c @@ -17,6 +17,7 @@ #include <linux/fs.h> #include <linux/cpu.h> #include <linux/percpu.h> +#include <linux/ctype.h> #include <asm/processor.h> #include <asm/msr.h> #include <asm/mce.h> @@ -36,6 +37,7 @@ static unsigned long bank[NR_BANKS] = { [0 ... NR_BANKS-1] = ~0UL }; static unsigned long console_logged; static int notify_user; static int rip_msr; +static int mce_bootlog; /* * Lockless MCE logging infrastructure. @@ -52,27 +54,35 @@ void mce_log(struct mce *mce) { unsigned next, entry; mce->finished = 0; - smp_wmb(); + wmb(); for (;;) { entry = rcu_dereference(mcelog.next); - /* When the buffer fills up discard new entries. Assume - that the earlier errors are the more interesting. */ - if (entry >= MCE_LOG_LEN) { - set_bit(MCE_OVERFLOW, &mcelog.flags); - return; + /* The rmb forces the compiler to reload next in each + iteration */ + rmb(); + for (;;) { + /* When the buffer fills up discard new entries. Assume + that the earlier errors are the more interesting. */ + if (entry >= MCE_LOG_LEN) { + set_bit(MCE_OVERFLOW, &mcelog.flags); + return; + } + /* Old left over entry. Skip. */ + if (mcelog.entry[entry].finished) { + entry++; + continue; + } + break; } - /* Old left over entry. Skip. */ - if (mcelog.entry[entry].finished) - continue; smp_rmb(); next = entry + 1; if (cmpxchg(&mcelog.next, entry, next) == entry) break; } memcpy(mcelog.entry + entry, mce, sizeof(struct mce)); - smp_wmb(); + wmb(); mcelog.entry[entry].finished = 1; - smp_wmb(); + wmb(); if (!test_and_set_bit(0, &console_logged)) notify_user = 1; @@ -197,10 +207,11 @@ void do_machine_check(struct pt_regs * regs, long error_code) rdmsrl(MSR_IA32_MC0_ADDR + i*4, m.addr); mce_get_rip(&m, regs); - if (error_code != -1) + if (error_code >= 0) rdtscll(m.tsc); wrmsrl(MSR_IA32_MC0_STATUS + i*4, 0); - mce_log(&m); + if (error_code != -2) + mce_log(&m); /* Did this bank cause the exception? */ /* Assume that the bank with uncorrectable errors did it, @@ -210,7 +221,7 @@ void do_machine_check(struct pt_regs * regs, long error_code) panicm_found = 1; } - tainted |= TAINT_MACHINE_CHECK; + add_taint(TAINT_MACHINE_CHECK); } /* Never do anything final in the polling timer */ @@ -315,7 +326,7 @@ static void mce_init(void *dummy) /* Log the machine checks left over from the previous reset. This also clears all registers */ - do_machine_check(NULL, -1); + do_machine_check(NULL, mce_bootlog ? -1 : -2); set_in_cr4(X86_CR4_MCE); @@ -402,9 +413,15 @@ static ssize_t mce_read(struct file *filp, char __user *ubuf, size_t usize, loff } err = 0; - for (i = 0; i < next; i++) { - if (!mcelog.entry[i].finished) - continue; + for (i = 0; i < next; i++) { + unsigned long start = jiffies; + while (!mcelog.entry[i].finished) { + if (!time_before(jiffies, start + 2)) { + memset(mcelog.entry + i,0, sizeof(struct mce)); + continue; + } + cpu_relax(); + } smp_rmb(); err |= copy_to_user(buf, mcelog.entry + i, sizeof(struct mce)); buf += sizeof(struct mce); @@ -476,11 +493,20 @@ static int __init mcheck_disable(char *str) } /* mce=off disables machine check. Note you can reenable it later - using sysfs */ + using sysfs. + mce=TOLERANCELEVEL (number, see above) + mce=bootlog Log MCEs from before booting. Disabled by default to work + around buggy BIOS that leave bogus MCEs. */ static int __init mcheck_enable(char *str) { + if (*str == '=') + str++; if (!strcmp(str, "off")) mce_dont_init = 1; + else if (!strcmp(str, "bootlog")) + mce_bootlog = 1; + else if (isdigit(str[0])) + get_option(&str, &tolerant); else printk("mce= argument %s ignored. Please use /sys", str); return 0; @@ -493,10 +519,12 @@ __setup("mce", mcheck_enable); * Sysfs support */ -/* On resume clear all MCE state. Don't want to see leftovers from the BIOS. */ +/* On resume clear all MCE state. Don't want to see leftovers from the BIOS. + Only one CPU is active at this time, the others get readded later using + CPU hotplug. */ static int mce_resume(struct sys_device *dev) { - on_each_cpu(mce_init, NULL, 1, 1); + mce_init(NULL); return 0; } |