Merge branch 'ras-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 RAS updates from Thomas Gleixner:
 "A small set of changes to the RAS core:

   - Rework of the MCE bank scanning code

   - Y2038 converion"

* 'ras-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mce: Cleanup __mc_scan_banks()
  x86/mce: Carve out bank scanning code
  x86/mce: Remove !banks check
  x86/mce: Carve out the crashing_cpu check
  x86/mce: Always use 64-bit timestamps

1 files changed, 107 insertions, 95 deletions

diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 8c50754c09c1..4b767284b7f5 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -123,8 +123,8 @@ void mce_setup(struct mce *m)
 {
 	memset(m, 0, sizeof(struct mce));
 	m->cpu = m->extcpu = smp_processor_id();
-	/* We hope get_seconds stays lockless */
-	m->time = get_seconds();
+	/* need the internal __ version to avoid deadlocks */
+	m->time = __ktime_get_real_seconds();
 	m->cpuvendor = boot_cpu_data.x86_vendor;
 	m->cpuid = cpuid_eax(1);
 	m->socketid = cpu_data(m->extcpu).phys_proc_id;
@@ -1104,6 +1104,101 @@ static void mce_unmap_kpfn(unsigned long pfn)
 }
 #endif
 
+
+/*
+ * Cases where we avoid rendezvous handler timeout:
+ * 1) If this CPU is offline.
+ *
+ * 2) If crashing_cpu was set, e.g. we're entering kdump and we need to
+ *  skip those CPUs which remain looping in the 1st kernel - see
+ *  crash_nmi_callback().
+ *
+ * Note: there still is a small window between kexec-ing and the new,
+ * kdump kernel establishing a new #MC handler where a broadcasted MCE
+ * might not get handled properly.
+ */
+static bool __mc_check_crashing_cpu(int cpu)
+{
+	if (cpu_is_offline(cpu) ||
+	    (crashing_cpu != -1 && crashing_cpu != cpu)) {
+		u64 mcgstatus;
+
+		mcgstatus = mce_rdmsrl(MSR_IA32_MCG_STATUS);
+		if (mcgstatus & MCG_STATUS_RIPV) {
+			mce_wrmsrl(MSR_IA32_MCG_STATUS, 0);
+			return true;
+		}
+	}
+	return false;
+}
+
+static void __mc_scan_banks(struct mce *m, struct mce *final,
+			    unsigned long *toclear, unsigned long *valid_banks,
+			    int no_way_out, int *worst)
+{
+	struct mca_config *cfg = &mca_cfg;
+	int severity, i;
+
+	for (i = 0; i < cfg->banks; i++) {
+		__clear_bit(i, toclear);
+		if (!test_bit(i, valid_banks))
+			continue;
+
+		if (!mce_banks[i].ctl)
+			continue;
+
+		m->misc = 0;
+		m->addr = 0;
+		m->bank = i;
+
+		m->status = mce_rdmsrl(msr_ops.status(i));
+		if (!(m->status & MCI_STATUS_VAL))
+			continue;
+
+		/*
+		 * Corrected or non-signaled errors are handled by
+		 * machine_check_poll(). Leave them alone, unless this panics.
+		 */
+		if (!(m->status & (cfg->ser ? MCI_STATUS_S : MCI_STATUS_UC)) &&
+			!no_way_out)
+			continue;
+
+		/* Set taint even when machine check was not enabled. */
+		add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
+
+		severity = mce_severity(m, cfg->tolerant, NULL, true);
+
+		/*
+		 * When machine check was for corrected/deferred handler don't
+		 * touch, unless we're panicking.
+		 */
+		if ((severity == MCE_KEEP_SEVERITY ||
+		     severity == MCE_UCNA_SEVERITY) && !no_way_out)
+			continue;
+
+		__set_bit(i, toclear);
+
+		/* Machine check event was not enabled. Clear, but ignore. */
+		if (severity == MCE_NO_SEVERITY)
+			continue;
+
+		mce_read_aux(m, i);
+
+		/* assuming valid severity level != 0 */
+		m->severity = severity;
+
+		mce_log(m);
+
+		if (severity > *worst) {
+			*final = *m;
+			*worst = severity;
+		}
+	}
+
+	/* mce_clear_state will clear *final, save locally for use later */
+	*m = *final;
+}
+
 /*
  * The actual machine check handler. This only handles real
  * exceptions when something got corrupted coming in through int 18.
@@ -1118,68 +1213,45 @@ static void mce_unmap_kpfn(unsigned long pfn)
  */
 void do_machine_check(struct pt_regs *regs, long error_code)
 {
+	DECLARE_BITMAP(valid_banks, MAX_NR_BANKS);
+	DECLARE_BITMAP(toclear, MAX_NR_BANKS);
 	struct mca_config *cfg = &mca_cfg;
+	int cpu = smp_processor_id();
+	char *msg = "Unknown";
 	struct mce m, *final;
-	int i;
 	int worst = 0;
-	int severity;
 
 	/*
 	 * Establish sequential order between the CPUs entering the machine
 	 * check handler.
 	 */
 	int order = -1;
+
 	/*
 	 * If no_way_out gets set, there is no safe way to recover from this
 	 * MCE.  If mca_cfg.tolerant is cranked up, we'll try anyway.
 	 */
 	int no_way_out = 0;
+
 	/*
 	 * If kill_it gets set, there might be a way to recover from this
 	 * error.
 	 */
 	int kill_it = 0;
-	DECLARE_BITMAP(toclear, MAX_NR_BANKS);
-	DECLARE_BITMAP(valid_banks, MAX_NR_BANKS);
-	char *msg = "Unknown";
 
 	/*
 	 * MCEs are always local on AMD. Same is determined by MCG_STATUS_LMCES
 	 * on Intel.
 	 */
 	int lmce = 1;
-	int cpu = smp_processor_id();
 
-	/*
-	 * Cases where we avoid rendezvous handler timeout:
-	 * 1) If this CPU is offline.
-	 *
-	 * 2) If crashing_cpu was set, e.g. we're entering kdump and we need to
-	 *  skip those CPUs which remain looping in the 1st kernel - see
-	 *  crash_nmi_callback().
-	 *
-	 * Note: there still is a small window between kexec-ing and the new,
-	 * kdump kernel establishing a new #MC handler where a broadcasted MCE
-	 * might not get handled properly.
-	 */
-	if (cpu_is_offline(cpu) ||
-	    (crashing_cpu != -1 && crashing_cpu != cpu)) {
-		u64 mcgstatus;
-
-		mcgstatus = mce_rdmsrl(MSR_IA32_MCG_STATUS);
-		if (mcgstatus & MCG_STATUS_RIPV) {
-			mce_wrmsrl(MSR_IA32_MCG_STATUS, 0);
-			return;
-		}
-	}
+	if (__mc_check_crashing_cpu(cpu))
+		return;
 
 	ist_enter(regs);
 
 	this_cpu_inc(mce_exception_count);
 
-	if (!cfg->banks)
-		goto out;
-
 	mce_gather_info(&m, regs);
 	m.tsc = rdtsc();
 
@@ -1220,67 +1292,7 @@ void do_machine_check(struct pt_regs *regs, long error_code)
 		order = mce_start(&no_way_out);
 	}
 
-	for (i = 0; i < cfg->banks; i++) {
-		__clear_bit(i, toclear);
-		if (!test_bit(i, valid_banks))
-			continue;
-		if (!mce_banks[i].ctl)
-			continue;
-
-		m.misc = 0;
-		m.addr = 0;
-		m.bank = i;
-
-		m.status = mce_rdmsrl(msr_ops.status(i));
-		if ((m.status & MCI_STATUS_VAL) == 0)
-			continue;
-
-		/*
-		 * Non uncorrected or non signaled errors are handled by
-		 * machine_check_poll. Leave them alone, unless this panics.
-		 */
-		if (!(m.status & (cfg->ser ? MCI_STATUS_S : MCI_STATUS_UC)) &&
-			!no_way_out)
-			continue;
-
-		/*
-		 * Set taint even when machine check was not enabled.
-		 */
-		add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
-
-		severity = mce_severity(&m, cfg->tolerant, NULL, true);
-
-		/*
-		 * When machine check was for corrected/deferred handler don't
-		 * touch, unless we're panicing.
-		 */
-		if ((severity == MCE_KEEP_SEVERITY ||
-		     severity == MCE_UCNA_SEVERITY) && !no_way_out)
-			continue;
-		__set_bit(i, toclear);
-		if (severity == MCE_NO_SEVERITY) {
-			/*
-			 * Machine check event was not enabled. Clear, but
-			 * ignore.
-			 */
-			continue;
-		}
-
-		mce_read_aux(&m, i);
-
-		/* assuming valid severity level != 0 */
-		m.severity = severity;
-
-		mce_log(&m);
-
-		if (severity > worst) {
-			*final = m;
-			worst = severity;
-		}
-	}
-
-	/* mce_clear_state will clear *final, save locally for use later */
-	m = *final;
+	__mc_scan_banks(&m, final, toclear, valid_banks, no_way_out, &worst);
 
 	if (!no_way_out)
 		mce_clear_state(toclear);
@@ -1319,7 +1331,7 @@ void do_machine_check(struct pt_regs *regs, long error_code)
 	if (worst > 0)
 		mce_report_event(regs);
 	mce_wrmsrl(MSR_IA32_MCG_STATUS, 0);
-out:
+
 	sync_core();
 
 	if (worst != MCE_AR_SEVERITY && !kill_it)