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authorLinus Torvalds <torvalds@linux-foundation.org>2012-03-22 09:42:04 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-03-22 09:42:04 -0700
commit754b9800779402924fffe456b49d557e15260cbf (patch)
tree0e0441eca766616fccd8fc37a3885397efc6063a /arch
parent35cb8d9e18c0bb33b90d7e574abadbe23b65427d (diff)
parentea281a9ebaba3287130dbe15bb0aad6f798bb06b (diff)
Merge branch 'x86-mce-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull MCE changes from Ingo Molnar. * 'x86-mce-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mce: Fix return value of mce_chrdev_read() when erst is disabled x86/mce: Convert static array of pointers to per-cpu variables x86/mce: Replace hard coded hex constants with symbolic defines x86/mce: Recognise machine check bank signature for data path error x86/mce: Handle "action required" errors x86/mce: Add mechanism to safely save information in MCE handler x86/mce: Create helper function to save addr/misc when needed HWPOISON: Add code to handle "action required" errors. HWPOISON: Clean up memory_failure() vs. __memory_failure()
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/include/asm/mce.h2
-rw-r--r--arch/x86/kernel/cpu/mcheck/mce-severity.c26
-rw-r--r--arch/x86/kernel/cpu/mcheck/mce.c193
-rw-r--r--arch/x86/kernel/cpu/mcheck/mce_amd.c9
4 files changed, 165 insertions, 65 deletions
diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h
index 6aefb14cbbc5..441520e4174f 100644
--- a/arch/x86/include/asm/mce.h
+++ b/arch/x86/include/asm/mce.h
@@ -151,7 +151,7 @@ static inline void enable_p5_mce(void) {}
void mce_setup(struct mce *m);
void mce_log(struct mce *m);
-extern struct device *mce_device[CONFIG_NR_CPUS];
+DECLARE_PER_CPU(struct device *, mce_device);
/*
* Maximum banks number.
diff --git a/arch/x86/kernel/cpu/mcheck/mce-severity.c b/arch/x86/kernel/cpu/mcheck/mce-severity.c
index 7395d5f4272d..0c82091b1652 100644
--- a/arch/x86/kernel/cpu/mcheck/mce-severity.c
+++ b/arch/x86/kernel/cpu/mcheck/mce-severity.c
@@ -54,7 +54,14 @@ static struct severity {
#define MASK(x, y) .mask = x, .result = y
#define MCI_UC_S (MCI_STATUS_UC|MCI_STATUS_S)
#define MCI_UC_SAR (MCI_STATUS_UC|MCI_STATUS_S|MCI_STATUS_AR)
+#define MCI_ADDR (MCI_STATUS_ADDRV|MCI_STATUS_MISCV)
#define MCACOD 0xffff
+/* Architecturally defined codes from SDM Vol. 3B Chapter 15 */
+#define MCACOD_SCRUB 0x00C0 /* 0xC0-0xCF Memory Scrubbing */
+#define MCACOD_SCRUBMSK 0xfff0
+#define MCACOD_L3WB 0x017A /* L3 Explicit Writeback */
+#define MCACOD_DATA 0x0134 /* Data Load */
+#define MCACOD_INSTR 0x0150 /* Instruction Fetch */
MCESEV(
NO, "Invalid",
@@ -102,11 +109,24 @@ static struct severity {
SER, BITCLR(MCI_STATUS_S)
),
- /* AR add known MCACODs here */
MCESEV(
PANIC, "Action required with lost events",
SER, BITSET(MCI_STATUS_OVER|MCI_UC_SAR)
),
+
+ /* known AR MCACODs: */
+#ifdef CONFIG_MEMORY_FAILURE
+ MCESEV(
+ KEEP, "HT thread notices Action required: data load error",
+ SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_DATA),
+ MCGMASK(MCG_STATUS_EIPV, 0)
+ ),
+ MCESEV(
+ AR, "Action required: data load error",
+ SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_DATA),
+ USER
+ ),
+#endif
MCESEV(
PANIC, "Action required: unknown MCACOD",
SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_SAR)
@@ -115,11 +135,11 @@ static struct severity {
/* known AO MCACODs: */
MCESEV(
AO, "Action optional: memory scrubbing error",
- SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|0xfff0, MCI_UC_S|0x00c0)
+ SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCACOD_SCRUBMSK, MCI_UC_S|MCACOD_SCRUB)
),
MCESEV(
AO, "Action optional: last level cache writeback error",
- SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCACOD, MCI_UC_S|0x017a)
+ SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCACOD, MCI_UC_S|MCACOD_L3WB)
),
MCESEV(
SOME, "Action optional: unknown MCACOD",
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 5a11ae2e9e91..c614bd4de0f3 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -540,6 +540,27 @@ static void mce_report_event(struct pt_regs *regs)
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);
/*
@@ -590,10 +611,7 @@ void machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
(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;
@@ -917,6 +935,49 @@ static void mce_clear_state(unsigned long *toclear)
}
/*
+ * 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.
*
@@ -969,7 +1030,9 @@ void do_machine_check(struct pt_regs *regs, long error_code)
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;
@@ -1023,16 +1086,7 @@ void do_machine_check(struct pt_regs *regs, long error_code)
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.
@@ -1052,6 +1106,9 @@ void do_machine_check(struct pt_regs *regs, long error_code)
}
}
+ /* mce_clear_state will clear *final, save locally for use later */
+ m = *final;
+
if (!no_way_out)
mce_clear_state(toclear);
@@ -1063,27 +1120,22 @@ void do_machine_check(struct pt_regs *regs, long error_code)
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);
@@ -1094,34 +1146,57 @@ 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)
+#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
@@ -1211,8 +1286,6 @@ int mce_notify_irq(void)
/* 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);
@@ -1541,6 +1614,12 @@ static int __mce_read_apei(char __user **ubuf, size_t usize)
/* Error or no more MCE record */
if (rc <= 0) {
mce_apei_read_done = 1;
+ /*
+ * When ERST is disabled, mce_chrdev_read() should return
+ * "no record" instead of "no device."
+ */
+ if (rc == -ENODEV)
+ return 0;
return rc;
}
rc = -EFAULT;
@@ -1859,7 +1938,7 @@ static struct bus_type mce_subsys = {
.dev_name = "machinecheck",
};
-struct device *mce_device[CONFIG_NR_CPUS];
+DEFINE_PER_CPU(struct device *, mce_device);
__cpuinitdata
void (*threshold_cpu_callback)(unsigned long action, unsigned int cpu);
@@ -2038,7 +2117,7 @@ static __cpuinit int mce_device_create(unsigned int cpu)
goto error2;
}
cpumask_set_cpu(cpu, mce_device_initialized);
- mce_device[cpu] = dev;
+ per_cpu(mce_device, cpu) = dev;
return 0;
error2:
@@ -2055,7 +2134,7 @@ error:
static __cpuinit void mce_device_remove(unsigned int cpu)
{
- struct device *dev = mce_device[cpu];
+ struct device *dev = per_cpu(mce_device, cpu);
int i;
if (!cpumask_test_cpu(cpu, mce_device_initialized))
@@ -2069,7 +2148,7 @@ static __cpuinit void mce_device_remove(unsigned int cpu)
device_unregister(dev);
cpumask_clear_cpu(cpu, mce_device_initialized);
- mce_device[cpu] = NULL;
+ per_cpu(mce_device, cpu) = NULL;
}
/* Make sure there are no machine checks on offlined CPUs. */
diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c
index e4eeaaf58a47..99b57179f912 100644
--- a/arch/x86/kernel/cpu/mcheck/mce_amd.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c
@@ -523,7 +523,7 @@ static __cpuinit int threshold_create_bank(unsigned int cpu, unsigned int bank)
{
int i, err = 0;
struct threshold_bank *b = NULL;
- struct device *dev = mce_device[cpu];
+ struct device *dev = per_cpu(mce_device, cpu);
char name[32];
sprintf(name, "threshold_bank%i", bank);
@@ -587,7 +587,7 @@ static __cpuinit int threshold_create_bank(unsigned int cpu, unsigned int bank)
if (i == cpu)
continue;
- dev = mce_device[i];
+ dev = per_cpu(mce_device, i);
if (dev)
err = sysfs_create_link(&dev->kobj,b->kobj, name);
if (err)
@@ -667,7 +667,8 @@ static void threshold_remove_bank(unsigned int cpu, int bank)
#ifdef CONFIG_SMP
/* sibling symlink */
if (shared_bank[bank] && b->blocks->cpu != cpu) {
- sysfs_remove_link(&mce_device[cpu]->kobj, name);
+ dev = per_cpu(mce_device, cpu);
+ sysfs_remove_link(&dev->kobj, name);
per_cpu(threshold_banks, cpu)[bank] = NULL;
return;
@@ -679,7 +680,7 @@ static void threshold_remove_bank(unsigned int cpu, int bank)
if (i == cpu)
continue;
- dev = mce_device[i];
+ dev = per_cpu(mce_device, i);
if (dev)
sysfs_remove_link(&dev->kobj, name);
per_cpu(threshold_banks, i)[bank] = NULL;