1 files changed, 76 insertions, 5 deletions

diff --git a/arch/x86_64/kernel/nmi.c b/arch/x86_64/kernel/nmi.c
index ab421e22fa67..399489c93132 100644
--- a/arch/x86_64/kernel/nmi.c
+++ b/arch/x86_64/kernel/nmi.c
@@ -27,6 +27,7 @@
 #include <asm/proto.h>
 #include <asm/kdebug.h>
 #include <asm/mce.h>
+#include <asm/intel_arch_perfmon.h>
 
 /*
  * lapic_nmi_owner tracks the ownership of the lapic NMI hardware:
@@ -66,6 +67,9 @@ static unsigned int nmi_p4_cccr_val;
 #define K7_EVENT_CYCLES_PROCESSOR_IS_RUNNING    0x76
 #define K7_NMI_EVENT            K7_EVENT_CYCLES_PROCESSOR_IS_RUNNING
 
+#define ARCH_PERFMON_NMI_EVENT_SEL      ARCH_PERFMON_UNHALTED_CORE_CYCLES_SEL
+#define ARCH_PERFMON_NMI_EVENT_UMASK    ARCH_PERFMON_UNHALTED_CORE_CYCLES_UMASK
+
 #define MSR_P4_MISC_ENABLE      0x1A0
 #define MSR_P4_MISC_ENABLE_PERF_AVAIL   (1<<7)
 #define MSR_P4_MISC_ENABLE_PEBS_UNAVAIL (1<<12)
@@ -97,7 +101,10 @@ static __cpuinit inline int nmi_known_cpu(void)
         case X86_VENDOR_AMD:
                 return boot_cpu_data.x86 == 15;
         case X86_VENDOR_INTEL:
-                return boot_cpu_data.x86 == 15;
+                if (cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON))
+                        return 1;
+                else
+                        return (boot_cpu_data.x86 == 15);
         }
         return 0;
 }
@@ -203,6 +210,8 @@ int __init setup_nmi_watchdog(char *str)
 
 __setup("nmi_watchdog=", setup_nmi_watchdog);
 
+static void disable_intel_arch_watchdog(void);
+
 static void disable_lapic_nmi_watchdog(void)
 {
         if (nmi_active <= 0)
@@ -215,6 +224,8 @@ static void disable_lapic_nmi_watchdog(void)
                 if (boot_cpu_data.x86 == 15) {
                         wrmsr(MSR_P4_IQ_CCCR0, 0, 0);
                         wrmsr(MSR_P4_CRU_ESCR0, 0, 0);
+                } else if (cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON)) {
+                        disable_intel_arch_watchdog();
                 }
                 break;
         }
@@ -367,6 +378,53 @@ static void setup_k7_watchdog(void)
         wrmsr(MSR_K7_EVNTSEL0, evntsel, 0);
 }
 
+static void disable_intel_arch_watchdog(void)
+{
+        unsigned ebx;
+
+        /*
+         * Check whether the Architectural PerfMon supports
+         * Unhalted Core Cycles Event or not.
+         * NOTE: Corresponding bit = 0 in ebp indicates event present.
+         */
+        ebx = cpuid_ebx(10);
+        if (!(ebx & ARCH_PERFMON_UNHALTED_CORE_CYCLES_PRESENT))
+                wrmsr(MSR_ARCH_PERFMON_EVENTSEL0, 0, 0);
+}
+
+static int setup_intel_arch_watchdog(void)
+{
+        unsigned int evntsel;
+        unsigned ebx;
+
+        /*
+         * Check whether the Architectural PerfMon supports
+         * Unhalted Core Cycles Event or not.
+         * NOTE: Corresponding bit = 0 in ebp indicates event present.
+         */
+        ebx = cpuid_ebx(10);
+        if ((ebx & ARCH_PERFMON_UNHALTED_CORE_CYCLES_PRESENT))
+                return 0;
+
+        nmi_perfctr_msr = MSR_ARCH_PERFMON_PERFCTR0;
+
+        clear_msr_range(MSR_ARCH_PERFMON_EVENTSEL0, 2);
+        clear_msr_range(MSR_ARCH_PERFMON_PERFCTR0, 2);
+
+        evntsel = ARCH_PERFMON_EVENTSEL_INT
+                | ARCH_PERFMON_EVENTSEL_OS
+                | ARCH_PERFMON_EVENTSEL_USR
+                | ARCH_PERFMON_NMI_EVENT_SEL
+                | ARCH_PERFMON_NMI_EVENT_UMASK;
+
+        wrmsr(MSR_ARCH_PERFMON_EVENTSEL0, evntsel, 0);
+        wrmsrl(MSR_ARCH_PERFMON_PERFCTR0, -((u64)cpu_khz * 1000 / nmi_hz));
+        apic_write(APIC_LVTPC, APIC_DM_NMI);
+        evntsel |= ARCH_PERFMON_EVENTSEL0_ENABLE;
+        wrmsr(MSR_ARCH_PERFMON_EVENTSEL0, evntsel, 0);
+        return 1;
+}
+
 
 static int setup_p4_watchdog(void)
 {
@@ -420,10 +478,16 @@ void setup_apic_nmi_watchdog(void)
                 setup_k7_watchdog();
                 break;
         case X86_VENDOR_INTEL:
-                if (boot_cpu_data.x86 != 15)
-                        return;
-                if (!setup_p4_watchdog())
+                if (cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON)) {
+                        if (!setup_intel_arch_watchdog())
+                                return;
+                } else if (boot_cpu_data.x86 == 15) {
+                        if (!setup_p4_watchdog())
+                                return;
+                } else {
                         return;
+                }
+
                 break;
 
         default:
@@ -508,7 +572,14 @@ void __kprobes nmi_watchdog_tick(struct pt_regs * regs, unsigned reason)
                          */
                         wrmsr(MSR_P4_IQ_CCCR0, nmi_p4_cccr_val, 0);
                         apic_write(APIC_LVTPC, APIC_DM_NMI);
-                }
+                } else if (nmi_perfctr_msr == MSR_ARCH_PERFMON_PERFCTR0) {
+                        /*
+                         * For Intel based architectural perfmon
+                         * - LVTPC is masked on interrupt and must be
+                         *   unmasked by the LVTPC handler.
+                         */
+                        apic_write(APIC_LVTPC, APIC_DM_NMI);
+                }
                 wrmsrl(nmi_perfctr_msr, -((u64)cpu_khz * 1000 / nmi_hz));
         }
 }