1 files changed, 115 insertions, 91 deletions

diff --git a/arch/x86/kernel/cpu/perfctr-watchdog.c b/arch/x86/kernel/cpu/perfctr-watchdog.c
index f9ae93adffe5..2e9bef6e3aa3 100644
--- a/arch/x86/kernel/cpu/perfctr-watchdog.c
+++ b/arch/x86/kernel/cpu/perfctr-watchdog.c
@@ -1,11 +1,15 @@
-/* local apic based NMI watchdog for various CPUs.
-   This file also handles reservation of performance counters for coordination
-   with other users (like oprofile).
-
-   Note that these events normally don't tick when the CPU idles. This means
-   the frequency varies with CPU load.
-
-   Original code for K7/P6 written by Keith Owens */
+/*
+ * local apic based NMI watchdog for various CPUs.
+ *
+ * This file also handles reservation of performance counters for coordination
+ * with other users (like oprofile).
+ *
+ * Note that these events normally don't tick when the CPU idles. This means
+ * the frequency varies with CPU load.
+ *
+ * Original code for K7/P6 written by Keith Owens
+ *
+ */
 
 #include <linux/percpu.h>
 #include <linux/module.h>
@@ -36,12 +40,16 @@ struct wd_ops {
 
 static const struct wd_ops *wd_ops;
 
-/* this number is calculated from Intel's MSR_P4_CRU_ESCR5 register and it's
- * offset from MSR_P4_BSU_ESCR0.  It will be the max for all platforms (for now)
+/*
+ * this number is calculated from Intel's MSR_P4_CRU_ESCR5 register and it's
+ * offset from MSR_P4_BSU_ESCR0.
+ *
+ * It will be the max for all platforms (for now)
  */
 #define NMI_MAX_COUNTER_BITS 66
 
-/* perfctr_nmi_owner tracks the ownership of the perfctr registers:
+/*
+ * perfctr_nmi_owner tracks the ownership of the perfctr registers:
  * evtsel_nmi_owner tracks the ownership of the event selection
  * - different performance counters/ event selection may be reserved for
  *   different subsystems this reservation system just tries to coordinate
@@ -73,8 +81,10 @@ static inline unsigned int nmi_perfctr_msr_to_bit(unsigned int msr)
         return 0;
 }
 
-/* converts an msr to an appropriate reservation bit */
-/* returns the bit offset of the event selection register */
+/*
+ * converts an msr to an appropriate reservation bit
+ * returns the bit offset of the event selection register
+ */
 static inline unsigned int nmi_evntsel_msr_to_bit(unsigned int msr)
 {
         /* returns the bit offset of the event selection register */
@@ -114,6 +124,7 @@ int avail_to_resrv_perfctr_nmi(unsigned int msr)
 
         return (!test_bit(counter, perfctr_nmi_owner));
 }
+EXPORT_SYMBOL(avail_to_resrv_perfctr_nmi_bit);
 
 int reserve_perfctr_nmi(unsigned int msr)
 {
@@ -128,6 +139,7 @@ int reserve_perfctr_nmi(unsigned int msr)
                 return 1;
         return 0;
 }
+EXPORT_SYMBOL(reserve_perfctr_nmi);
 
 void release_perfctr_nmi(unsigned int msr)
 {
@@ -140,6 +152,7 @@ void release_perfctr_nmi(unsigned int msr)
 
         clear_bit(counter, perfctr_nmi_owner);
 }
+EXPORT_SYMBOL(release_perfctr_nmi);
 
 int reserve_evntsel_nmi(unsigned int msr)
 {
@@ -154,6 +167,7 @@ int reserve_evntsel_nmi(unsigned int msr)
                 return 1;
         return 0;
 }
+EXPORT_SYMBOL(reserve_evntsel_nmi);
 
 void release_evntsel_nmi(unsigned int msr)
 {
@@ -166,11 +180,6 @@ void release_evntsel_nmi(unsigned int msr)
 
         clear_bit(counter, evntsel_nmi_owner);
 }
-
-EXPORT_SYMBOL(avail_to_resrv_perfctr_nmi_bit);
-EXPORT_SYMBOL(reserve_perfctr_nmi);
-EXPORT_SYMBOL(release_perfctr_nmi);
-EXPORT_SYMBOL(reserve_evntsel_nmi);
 EXPORT_SYMBOL(release_evntsel_nmi);
 
 void disable_lapic_nmi_watchdog(void)
@@ -181,7 +190,9 @@ void disable_lapic_nmi_watchdog(void)
                 return;
 
         on_each_cpu(stop_apic_nmi_watchdog, NULL, 0, 1);
-        wd_ops->unreserve();
+
+        if (wd_ops)
+                wd_ops->unreserve();
 
         BUG_ON(atomic_read(&nmi_active) != 0);
 }
@@ -232,8 +243,8 @@ static unsigned int adjust_for_32bit_ctr(unsigned int hz)
         return retval;
 }
 
-static void
-write_watchdog_counter(unsigned int perfctr_msr, const char *descr, unsigned nmi_hz)
+static void write_watchdog_counter(unsigned int perfctr_msr,
+                                const char *descr, unsigned nmi_hz)
 {
         u64 count = (u64)cpu_khz * 1000;
 
@@ -244,7 +255,7 @@ write_watchdog_counter(unsigned int perfctr_msr, const char *descr, unsigned nmi
 }
 
 static void write_watchdog_counter32(unsigned int perfctr_msr,
-                const char *descr, unsigned nmi_hz)
+                                const char *descr, unsigned nmi_hz)
 {
         u64 count = (u64)cpu_khz * 1000;
 
@@ -254,9 +265,10 @@ static void write_watchdog_counter32(unsigned int perfctr_msr,
         wrmsr(perfctr_msr, (u32)(-count), 0);
 }
 
-/* AMD K7/K8/Family10h/Family11h support. AMD keeps this interface
-   nicely stable so there is not much variety */
-
+/*
+ * AMD K7/K8/Family10h/Family11h support.
+ * AMD keeps this interface nicely stable so there is not much variety
+ */
 #define K7_EVNTSEL_ENABLE       (1 << 22)
 #define K7_EVNTSEL_INT          (1 << 20)
 #define K7_EVNTSEL_OS           (1 << 17)
@@ -289,7 +301,7 @@ static int setup_k7_watchdog(unsigned nmi_hz)
 
         wd->perfctr_msr = perfctr_msr;
         wd->evntsel_msr = evntsel_msr;
-        wd->cccr_msr = 0;  //unused
+        wd->cccr_msr = 0;  /* unused */
         return 1;
 }
 
@@ -325,18 +337,19 @@ static void single_msr_rearm(struct nmi_watchdog_ctlblk *wd, unsigned nmi_hz)
 }
 
 static const struct wd_ops k7_wd_ops = {
-        .reserve = single_msr_reserve,
-        .unreserve = single_msr_unreserve,
-        .setup = setup_k7_watchdog,
-        .rearm = single_msr_rearm,
-        .stop = single_msr_stop_watchdog,
-        .perfctr = MSR_K7_PERFCTR0,
-        .evntsel = MSR_K7_EVNTSEL0,
-        .checkbit = 1ULL<<47,
+        .reserve        = single_msr_reserve,
+        .unreserve      = single_msr_unreserve,
+        .setup          = setup_k7_watchdog,
+        .rearm          = single_msr_rearm,
+        .stop           = single_msr_stop_watchdog,
+        .perfctr        = MSR_K7_PERFCTR0,
+        .evntsel        = MSR_K7_EVNTSEL0,
+        .checkbit       = 1ULL << 47,
 };
 
-/* Intel Model 6 (PPro+,P2,P3,P-M,Core1) */
-
+/*
+ * Intel Model 6 (PPro+,P2,P3,P-M,Core1)
+ */
 #define P6_EVNTSEL0_ENABLE      (1 << 22)
 #define P6_EVNTSEL_INT          (1 << 20)
 #define P6_EVNTSEL_OS           (1 << 17)
@@ -372,52 +385,58 @@ static int setup_p6_watchdog(unsigned nmi_hz)
 
         wd->perfctr_msr = perfctr_msr;
         wd->evntsel_msr = evntsel_msr;
-        wd->cccr_msr = 0;  //unused
+        wd->cccr_msr = 0;  /* unused */
         return 1;
 }
 
 static void p6_rearm(struct nmi_watchdog_ctlblk *wd, unsigned nmi_hz)
 {
-        /* P6 based Pentium M need to re-unmask
+        /*
+         * P6 based Pentium M need to re-unmask
          * the apic vector but it doesn't hurt
          * other P6 variant.
-         * ArchPerfom/Core Duo also needs this */
+         * ArchPerfom/Core Duo also needs this
+         */
         apic_write(APIC_LVTPC, APIC_DM_NMI);
+
         /* P6/ARCH_PERFMON has 32 bit counter write */
         write_watchdog_counter32(wd->perfctr_msr, NULL,nmi_hz);
 }
 
 static const struct wd_ops p6_wd_ops = {
-        .reserve = single_msr_reserve,
-        .unreserve = single_msr_unreserve,
-        .setup = setup_p6_watchdog,
-        .rearm = p6_rearm,
-        .stop = single_msr_stop_watchdog,
-        .perfctr = MSR_P6_PERFCTR0,
-        .evntsel = MSR_P6_EVNTSEL0,
-        .checkbit = 1ULL<<39,
+        .reserve        = single_msr_reserve,
+        .unreserve      = single_msr_unreserve,
+        .setup          = setup_p6_watchdog,
+        .rearm          = p6_rearm,
+        .stop           = single_msr_stop_watchdog,
+        .perfctr        = MSR_P6_PERFCTR0,
+        .evntsel        = MSR_P6_EVNTSEL0,
+        .checkbit       = 1ULL << 39,
 };
 
-/* Intel P4 performance counters. By far the most complicated of all. */
-
-#define MSR_P4_MISC_ENABLE_PERF_AVAIL   (1<<7)
-#define P4_ESCR_EVENT_SELECT(N) ((N)<<25)
-#define P4_ESCR_OS              (1<<3)
-#define P4_ESCR_USR             (1<<2)
-#define P4_CCCR_OVF_PMI0        (1<<26)
-#define P4_CCCR_OVF_PMI1        (1<<27)
-#define P4_CCCR_THRESHOLD(N)    ((N)<<20)
-#define P4_CCCR_COMPLEMENT      (1<<19)
-#define P4_CCCR_COMPARE         (1<<18)
-#define P4_CCCR_REQUIRED        (3<<16)
-#define P4_CCCR_ESCR_SELECT(N)  ((N)<<13)
-#define P4_CCCR_ENABLE          (1<<12)
-#define P4_CCCR_OVF             (1<<31)
-
-/* Set up IQ_COUNTER0 to behave like a clock, by having IQ_CCCR0 filter
-   CRU_ESCR0 (with any non-null event selector) through a complemented
-   max threshold. [IA32-Vol3, Section 14.9.9] */
+/*
+ * Intel P4 performance counters.
+ * By far the most complicated of all.
+ */
+#define MSR_P4_MISC_ENABLE_PERF_AVAIL   (1 << 7)
+#define P4_ESCR_EVENT_SELECT(N) ((N) << 25)
+#define P4_ESCR_OS              (1 << 3)
+#define P4_ESCR_USR             (1 << 2)
+#define P4_CCCR_OVF_PMI0        (1 << 26)
+#define P4_CCCR_OVF_PMI1        (1 << 27)
+#define P4_CCCR_THRESHOLD(N)    ((N) << 20)
+#define P4_CCCR_COMPLEMENT      (1 << 19)
+#define P4_CCCR_COMPARE         (1 << 18)
+#define P4_CCCR_REQUIRED        (3 << 16)
+#define P4_CCCR_ESCR_SELECT(N)  ((N) << 13)
+#define P4_CCCR_ENABLE          (1 << 12)
+#define P4_CCCR_OVF             (1 << 31)
 
+/*
+ * Set up IQ_COUNTER0 to behave like a clock, by having IQ_CCCR0 filter
+ * CRU_ESCR0 (with any non-null event selector) through a complemented
+ * max threshold. [IA32-Vol3, Section 14.9.9]
+ */
 static int setup_p4_watchdog(unsigned nmi_hz)
 {
         unsigned int perfctr_msr, evntsel_msr, cccr_msr;
@@ -442,7 +461,8 @@ static int setup_p4_watchdog(unsigned nmi_hz)
 #endif
                 ht_num = 0;
 
-        /* performance counters are shared resources
+        /*
+         * performance counters are shared resources
          * assign each hyperthread its own set
          * (re-use the ESCR0 register, seems safe
          * and keeps the cccr_val the same)
@@ -540,20 +560,21 @@ static void p4_rearm(struct nmi_watchdog_ctlblk *wd, unsigned nmi_hz)
 }
 
 static const struct wd_ops p4_wd_ops = {
-        .reserve = p4_reserve,
-        .unreserve = p4_unreserve,
-        .setup = setup_p4_watchdog,
-        .rearm = p4_rearm,
-        .stop = stop_p4_watchdog,
+        .reserve        = p4_reserve,
+        .unreserve      = p4_unreserve,
+        .setup          = setup_p4_watchdog,
+        .rearm          = p4_rearm,
+        .stop           = stop_p4_watchdog,
         /* RED-PEN this is wrong for the other sibling */
-        .perfctr = MSR_P4_BPU_PERFCTR0,
-        .evntsel = MSR_P4_BSU_ESCR0,
-        .checkbit = 1ULL<<39,
+        .perfctr        = MSR_P4_BPU_PERFCTR0,
+        .evntsel        = MSR_P4_BSU_ESCR0,
+        .checkbit       = 1ULL << 39,
 };
 
-/* Watchdog using the Intel architected PerfMon. Used for Core2 and hopefully
-   all future Intel CPUs. */
-
+/*
+ * Watchdog using the Intel architected PerfMon.
+ * Used for Core2 and hopefully all future Intel CPUs.
+ */
 #define ARCH_PERFMON_NMI_EVENT_SEL      ARCH_PERFMON_UNHALTED_CORE_CYCLES_SEL
 #define ARCH_PERFMON_NMI_EVENT_UMASK    ARCH_PERFMON_UNHALTED_CORE_CYCLES_UMASK
 
@@ -599,19 +620,19 @@ static int setup_intel_arch_watchdog(unsigned nmi_hz)
 
         wd->perfctr_msr = perfctr_msr;
         wd->evntsel_msr = evntsel_msr;
-        wd->cccr_msr = 0;  //unused
+        wd->cccr_msr = 0;  /* unused */
         intel_arch_wd_ops.checkbit = 1ULL << (eax.split.bit_width - 1);
         return 1;
 }
 
 static struct wd_ops intel_arch_wd_ops __read_mostly = {
-        .reserve = single_msr_reserve,
-        .unreserve = single_msr_unreserve,
-        .setup = setup_intel_arch_watchdog,
-        .rearm = p6_rearm,
-        .stop = single_msr_stop_watchdog,
-        .perfctr = MSR_ARCH_PERFMON_PERFCTR1,
-        .evntsel = MSR_ARCH_PERFMON_EVENTSEL1,
+        .reserve        = single_msr_reserve,
+        .unreserve      = single_msr_unreserve,
+        .setup          = setup_intel_arch_watchdog,
+        .rearm          = p6_rearm,
+        .stop           = single_msr_stop_watchdog,
+        .perfctr        = MSR_ARCH_PERFMON_PERFCTR1,
+        .evntsel        = MSR_ARCH_PERFMON_EVENTSEL1,
 };
 
 static void probe_nmi_watchdog(void)
@@ -624,8 +645,10 @@ static void probe_nmi_watchdog(void)
                 wd_ops = &k7_wd_ops;
                 break;
         case X86_VENDOR_INTEL:
-                /* Work around Core Duo (Yonah) errata AE49 where perfctr1
-                   doesn't have a working enable bit. */
+                /*
+                 * Work around Core Duo (Yonah) errata AE49 where perfctr1
+                 * doesn't have a working enable bit.
+                 */
                 if (boot_cpu_data.x86 == 6 && boot_cpu_data.x86_model == 14) {
                         intel_arch_wd_ops.perfctr = MSR_ARCH_PERFMON_PERFCTR0;
                         intel_arch_wd_ops.evntsel = MSR_ARCH_PERFMON_EVENTSEL0;
@@ -636,7 +659,7 @@ static void probe_nmi_watchdog(void)
                 }
                 switch (boot_cpu_data.x86) {
                 case 6:
-                        if (boot_cpu_data.x86_model > 0xd)
+                        if (boot_cpu_data.x86_model > 13)
                                 return;
 
                         wd_ops = &p6_wd_ops;
@@ -697,10 +720,11 @@ int lapic_wd_event(unsigned nmi_hz)
 {
         struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);
         u64 ctr;
+
         rdmsrl(wd->perfctr_msr, ctr);
-        if (ctr & wd_ops->checkbit) { /* perfctr still running? */
+        if (ctr & wd_ops->checkbit) /* perfctr still running? */
                 return 0;
-        }
+
         wd_ops->rearm(wd, nmi_hz);
         return 1;
 }