irq_work_queue(&__get_cpu_var(mce_irq_work));
}
+/*
+ * Read ADDR and MISC registers.
+ */
+static void mce_read_aux(struct mce *m, int i)
+{
+ if (m->status & MCI_STATUS_MISCV)
+ m->misc = mce_rdmsrl(MSR_IA32_MCx_MISC(i));
+ if (m->status & MCI_STATUS_ADDRV) {
+ m->addr = mce_rdmsrl(MSR_IA32_MCx_ADDR(i));
+
+ /*
+ * Mask the reported address by the reported granularity.
+ */
+ if (mce_ser && (m->status & MCI_STATUS_MISCV)) {
+ u8 shift = MCI_MISC_ADDR_LSB(m->misc);
+ m->addr >>= shift;
+ m->addr <<= shift;
+ }
+ }
+}
+
DEFINE_PER_CPU(unsigned, mce_poll_count);
/*
(m.status & (mce_ser ? MCI_STATUS_S : MCI_STATUS_UC)))
continue;
- if (m.status & MCI_STATUS_MISCV)
- m.misc = mce_rdmsrl(MSR_IA32_MCx_MISC(i));
- if (m.status & MCI_STATUS_ADDRV)
- m.addr = mce_rdmsrl(MSR_IA32_MCx_ADDR(i));
+ mce_read_aux(&m, i);
if (!(flags & MCP_TIMESTAMP))
m.tsc = 0;
}
}
+/*
+ * Need to save faulting physical address associated with a process
+ * in the machine check handler some place where we can grab it back
+ * later in mce_notify_process()
+ */
+#define MCE_INFO_MAX 16
+
+struct mce_info {
+ atomic_t inuse;
+ struct task_struct *t;
+ __u64 paddr;
+} mce_info[MCE_INFO_MAX];
+
+static void mce_save_info(__u64 addr)
+{
+ struct mce_info *mi;
+
+ for (mi = mce_info; mi < &mce_info[MCE_INFO_MAX]; mi++) {
+ if (atomic_cmpxchg(&mi->inuse, 0, 1) == 0) {
+ mi->t = current;
+ mi->paddr = addr;
+ return;
+ }
+ }
+
+ mce_panic("Too many concurrent recoverable errors", NULL, NULL);
+}
+
+static struct mce_info *mce_find_info(void)
+{
+ struct mce_info *mi;
+
+ for (mi = mce_info; mi < &mce_info[MCE_INFO_MAX]; mi++)
+ if (atomic_read(&mi->inuse) && mi->t == current)
+ return mi;
+ return NULL;
+}
+
+static void mce_clear_info(struct mce_info *mi)
+{
+ atomic_set(&mi->inuse, 0);
+}
+
/*
* The actual machine check handler. This only handles real
* exceptions when something got corrupted coming in through int 18.
barrier();
/*
- * When no restart IP must always kill or panic.
+ * When no restart IP might need to kill or panic.
+ * Assume the worst for now, but if we find the
+ * severity is MCE_AR_SEVERITY we have other options.
*/
if (!(m.mcgstatus & MCG_STATUS_RIPV))
kill_it = 1;
continue;
}
- /*
- * Kill on action required.
- */
- if (severity == MCE_AR_SEVERITY)
- kill_it = 1;
-
- if (m.status & MCI_STATUS_MISCV)
- m.misc = mce_rdmsrl(MSR_IA32_MCx_MISC(i));
- if (m.status & MCI_STATUS_ADDRV)
- m.addr = mce_rdmsrl(MSR_IA32_MCx_ADDR(i));
+ mce_read_aux(&m, i);
/*
* Action optional error. Queue address for later processing.
}
}
+ /* mce_clear_state will clear *final, save locally for use later */
+ m = *final;
+
if (!no_way_out)
mce_clear_state(toclear);
no_way_out = worst >= MCE_PANIC_SEVERITY;
/*
- * If we have decided that we just CAN'T continue, and the user
- * has not set tolerant to an insane level, give up and die.
- *
- * This is mainly used in the case when the system doesn't
- * support MCE broadcasting or it has been disabled.
- */
- if (no_way_out && tolerant < 3)
- mce_panic("Fatal machine check on current CPU", final, msg);
-
- /*
- * If the error seems to be unrecoverable, something should be
- * done. Try to kill as little as possible. If we can kill just
- * one task, do that. If the user has set the tolerance very
- * high, don't try to do anything at all.
+ * At insane "tolerant" levels we take no action. Otherwise
+ * we only die if we have no other choice. For less serious
+ * issues we try to recover, or limit damage to the current
+ * process.
*/
-
- if (kill_it && tolerant < 3)
- force_sig(SIGBUS, current);
-
- /* notify userspace ASAP */
- set_thread_flag(TIF_MCE_NOTIFY);
+ if (tolerant < 3) {
+ if (no_way_out)
+ mce_panic("Fatal machine check on current CPU", &m, msg);
+ if (worst == MCE_AR_SEVERITY) {
+ /* schedule action before return to userland */
+ mce_save_info(m.addr);
+ set_thread_flag(TIF_MCE_NOTIFY);
+ } else if (kill_it) {
+ force_sig(SIGBUS, current);
+ }
+ }
if (worst > 0)
mce_report_event(regs);
}
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)
+#ifndef CONFIG_MEMORY_FAILURE
+int memory_failure(unsigned long pfn, int vector, int flags)
{
- printk(KERN_ERR "Action optional memory failure at %lx ignored\n", pfn);
+ /* mce_severity() should not hand us an ACTION_REQUIRED error */
+ BUG_ON(flags & MF_ACTION_REQUIRED);
+ printk(KERN_ERR "Uncorrected memory error in page 0x%lx ignored\n"
+ "Rebuild kernel with CONFIG_MEMORY_FAILURE=y for smarter handling\n", pfn);
+
+ return 0;
}
+#endif
/*
- * 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.
+ * Called in process context that interrupted by MCE and marked with
+ * TIF_MCE_NOTIFY, just before returning to erroneous userland.
+ * This code is allowed to sleep.
+ * Attempt possible recovery such as calling the high level VM handler to
+ * process any corrupted pages, and kill/signal current process if required.
+ * Action required errors are handled here.
*/
void mce_notify_process(void)
{
unsigned long pfn;
- mce_notify_irq();
- while (mce_ring_get(&pfn))
- memory_failure(pfn, MCE_VECTOR);
+ struct mce_info *mi = mce_find_info();
+
+ if (!mi)
+ mce_panic("Lost physical address for unconsumed uncorrectable error", NULL, NULL);
+ pfn = mi->paddr >> PAGE_SHIFT;
+
+ clear_thread_flag(TIF_MCE_NOTIFY);
+
+ pr_err("Uncorrected hardware memory error in user-access at %llx",
+ mi->paddr);
+ if (memory_failure(pfn, MCE_VECTOR, MF_ACTION_REQUIRED) < 0) {
+ pr_err("Memory error not recovered");
+ force_sig(SIGBUS, current);
+ }
+ mce_clear_info(mi);
}
+/*
+ * Action optional processing happens here (picking up
+ * from the list of faulting pages that do_machine_check()
+ * placed into the "ring").
+ */
static void mce_process_work(struct work_struct *dummy)
{
- mce_notify_process();
+ unsigned long pfn;
+
+ while (mce_ring_get(&pfn))
+ memory_failure(pfn, MCE_VECTOR, 0);
}
#ifdef CONFIG_X86_MCE_INTEL
/* Not more than two messages every minute */
static DEFINE_RATELIMIT_STATE(ratelimit, 60*HZ, 2);
- clear_thread_flag(TIF_MCE_NOTIFY);
-
if (test_and_clear_bit(0, &mce_need_notify)) {
/* wake processes polling /dev/mcelog */
wake_up_interruptible(&mce_chrdev_wait);
projects / cascardo / linux.git / blobdiff