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Commit 754b9800 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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()
parents 35cb8d9e ea281a9e
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+1 −1
Original line number Diff line number Diff line
@@ -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.
+23 −3
Original line number Diff line number Diff line
@@ -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",
+136 −57
Original line number Diff line number Diff line
@@ -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;
@@ -916,6 +934,49 @@ 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 */
	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 @@ void do_machine_check(struct pt_regs *regs, long error_code)
}
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 @@ static __cpuinit int mce_device_create(unsigned int cpu)

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. */
+5 −4
Original line number Diff line number Diff line
@@ -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;
+1 −1
Original line number Diff line number Diff line
@@ -466,7 +466,7 @@ store_hard_offline_page(struct device *dev,
	if (strict_strtoull(buf, 0, &pfn) < 0)
		return -EINVAL;
	pfn >>= PAGE_SHIFT;
	ret = __memory_failure(pfn, 0, 0);
	ret = memory_failure(pfn, 0, 0);
	return ret ? ret : count;
}

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