diff options
| -rw-r--r-- | arch/x86/include/asm/mce.h | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/mcheck/mce.c | 133 | ||||
| -rw-r--r-- | arch/x86/kernel/signal.c | 2 |
3 files changed, 135 insertions, 1 deletions
diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h index 713926b62cbb..82978ad12072 100644 --- a/arch/x86/include/asm/mce.h +++ b/arch/x86/include/asm/mce.h @@ -160,6 +160,7 @@ enum mcp_flags { void machine_check_poll(enum mcp_flags flags, mce_banks_t *b); int mce_notify_irq(void); +void mce_notify_process(void); DECLARE_PER_CPU(struct mce, injectm); extern struct file_operations mce_chrdev_ops; diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 13e1b7ffe73a..d4e7b5947a0e 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -33,6 +33,7 @@ #include <linux/cpu.h> #include <linux/smp.h> #include <linux/fs.h> +#include <linux/mm.h> #include <asm/processor.h> #include <asm/hw_irq.h> @@ -105,6 +106,8 @@ static inline int skip_bank_init(int i) return i < BITS_PER_LONG && test_bit(i, &dont_init_banks); } +static DEFINE_PER_CPU(struct work_struct, mce_work); + /* Do initial initialization of a struct mce */ void mce_setup(struct mce *m) { @@ -312,6 +315,61 @@ static void mce_wrmsrl(u32 msr, u64 v) wrmsrl(msr, v); } +/* + * Simple lockless ring to communicate PFNs from the exception handler with the + * process context work function. This is vastly simplified because there's + * only a single reader and a single writer. + */ +#define MCE_RING_SIZE 16 /* we use one entry less */ + +struct mce_ring { + unsigned short start; + unsigned short end; + unsigned long ring[MCE_RING_SIZE]; +}; +static DEFINE_PER_CPU(struct mce_ring, mce_ring); + +/* Runs with CPU affinity in workqueue */ +static int mce_ring_empty(void) +{ + struct mce_ring *r = &__get_cpu_var(mce_ring); + + return r->start == r->end; +} + +static int mce_ring_get(unsigned long *pfn) +{ + struct mce_ring *r; + int ret = 0; + + *pfn = 0; + get_cpu(); + r = &__get_cpu_var(mce_ring); + if (r->start == r->end) + goto out; + *pfn = r->ring[r->start]; + r->start = (r->start + 1) % MCE_RING_SIZE; + ret = 1; +out: + put_cpu(); + return ret; +} + +/* Always runs in MCE context with preempt off */ +static int mce_ring_add(unsigned long pfn) +{ + struct mce_ring *r = &__get_cpu_var(mce_ring); + unsigned next; + + next = (r->end + 1) % MCE_RING_SIZE; + if (next == r->start) + return -1; + r->ring[r->end] = pfn; + wmb(); + r->end = next; + return 0; +} + int mce_available(struct cpuinfo_x86 *c) { if (mce_disabled) @@ -319,6 +377,15 @@ int mce_available(struct cpuinfo_x86 *c) return cpu_has(c, X86_FEATURE_MCE) && cpu_has(c, X86_FEATURE_MCA); } +static void mce_schedule_work(void) +{ + if (!mce_ring_empty()) { + struct work_struct *work = &__get_cpu_var(mce_work); + if (!work_pending(work)) + schedule_work(work); + } +} + /* * Get the address of the instruction at the time of the machine check * error. @@ -349,6 +416,7 @@ asmlinkage void smp_mce_self_interrupt(struct pt_regs *regs) exit_idle(); irq_enter(); mce_notify_irq(); + mce_schedule_work(); irq_exit(); } #endif @@ -357,6 +425,13 @@ static void mce_report_event(struct pt_regs *regs) { if (regs->flags & (X86_VM_MASK|X86_EFLAGS_IF)) { mce_notify_irq(); + /* + * Triggering the work queue here is just an insurance + * policy in case the syscall exit notify handler + * doesn't run soon enough or ends up running on the + * wrong CPU (can happen when audit sleeps) + */ + mce_schedule_work(); return; } @@ -731,6 +806,23 @@ reset: return ret; } +/* + * Check if the address reported by the CPU is in a format we can parse. + * It would be possible to add code for most other cases, but all would + * be somewhat complicated (e.g. segment offset would require an instruction + * parser). So only support physical addresses upto page granuality for now. + */ +static int mce_usable_address(struct mce *m) +{ + if (!(m->status & MCI_STATUS_MISCV) || !(m->status & MCI_STATUS_ADDRV)) + return 0; + if ((m->misc & 0x3f) > PAGE_SHIFT) + return 0; + if (((m->misc >> 6) & 7) != MCM_ADDR_PHYS) + return 0; + return 1; +} + static void mce_clear_state(unsigned long *toclear) { int i; @@ -865,6 +957,16 @@ void do_machine_check(struct pt_regs *regs, long error_code) if (m.status & MCI_STATUS_ADDRV) m.addr = mce_rdmsrl(MSR_IA32_MC0_ADDR + i*4); + /* + * Action optional error. Queue address for later processing. + * When the ring overflows we just ignore the AO error. + * RED-PEN add some logging mechanism when + * usable_address or mce_add_ring fails. + * RED-PEN don't ignore overflow for tolerant == 0 + */ + if (severity == MCE_AO_SEVERITY && mce_usable_address(&m)) + mce_ring_add(m.addr >> PAGE_SHIFT); + mce_get_rip(&m, regs); mce_log(&m); @@ -916,6 +1018,36 @@ out: } EXPORT_SYMBOL_GPL(do_machine_check); +/* dummy to break dependency. actual code is in mm/memory-failure.c */ +void __attribute__((weak)) memory_failure(unsigned long pfn, int vector) +{ + printk(KERN_ERR "Action optional memory failure at %lx ignored\n", pfn); +} + +/* + * Called after mce notification in process context. This code + * is allowed to sleep. Call the high level VM handler to process + * any corrupted pages. + * Assume that the work queue code only calls this one at a time + * per CPU. + * Note we don't disable preemption, so this code might run on the wrong + * CPU. In this case the event is picked up by the scheduled work queue. + * This is merely a fast path to expedite processing in some common + * cases. + */ +void mce_notify_process(void) +{ + unsigned long pfn; + mce_notify_irq(); + while (mce_ring_get(&pfn)) + memory_failure(pfn, MCE_VECTOR); +} + +static void mce_process_work(struct work_struct *dummy) +{ + mce_notify_process(); +} + #ifdef CONFIG_X86_MCE_INTEL /*** * mce_log_therm_throt_event - Logs the thermal throttling event to mcelog @@ -1204,6 +1336,7 @@ void __cpuinit mcheck_init(struct cpuinfo_x86 *c) mce_init(); mce_cpu_features(c); mce_init_timer(); + INIT_WORK(&__get_cpu_var(mce_work), mce_process_work); } /* diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index d5dc15bce005..4976888094f0 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -860,7 +860,7 @@ do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags) #ifdef CONFIG_X86_NEW_MCE /* notify userspace of pending MCEs */ if (thread_info_flags & _TIF_MCE_NOTIFY) - mce_notify_irq(); + mce_notify_process(); #endif /* CONFIG_X86_64 && CONFIG_X86_MCE */ /* deal with pending signal delivery */ |