Initial import

1 files changed, 160 insertions, 0 deletions

diff --git a/arch/x86/kernel/cpu/perfctr-watchdog.c b/arch/x86/kernel/cpu/perfctr-watchdog.c
new file mode 100644
index 000000000..2e8caf03f
--- /dev/null
+++ b/arch/x86/kernel/cpu/perfctr-watchdog.c
@@ -0,0 +1,160 @@
+/*
+ * 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>
+#include <linux/kernel.h>
+#include <linux/bitops.h>
+#include <linux/smp.h>
+#include <asm/nmi.h>
+#include <linux/kprobes.h>
+
+#include <asm/apic.h>
+#include <asm/perf_event.h>
+
+/*
+ * 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:
+ * 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
+ *   things a little
+ */
+static DECLARE_BITMAP(perfctr_nmi_owner, NMI_MAX_COUNTER_BITS);
+static DECLARE_BITMAP(evntsel_nmi_owner, NMI_MAX_COUNTER_BITS);
+
+/* converts an msr to an appropriate reservation bit */
+static inline unsigned int nmi_perfctr_msr_to_bit(unsigned int msr)
+{
+	/* returns the bit offset of the performance counter register */
+	switch (boot_cpu_data.x86_vendor) {
+	case X86_VENDOR_AMD:
+		if (msr >= MSR_F15H_PERF_CTR)
+			return (msr - MSR_F15H_PERF_CTR) >> 1;
+		return msr - MSR_K7_PERFCTR0;
+	case X86_VENDOR_INTEL:
+		if (cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON))
+			return msr - MSR_ARCH_PERFMON_PERFCTR0;
+
+		switch (boot_cpu_data.x86) {
+		case 6:
+			return msr - MSR_P6_PERFCTR0;
+		case 11:
+			return msr - MSR_KNC_PERFCTR0;
+		case 15:
+			return msr - MSR_P4_BPU_PERFCTR0;
+		}
+	}
+	return 0;
+}
+
+/*
+ * 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 */
+	switch (boot_cpu_data.x86_vendor) {
+	case X86_VENDOR_AMD:
+		if (msr >= MSR_F15H_PERF_CTL)
+			return (msr - MSR_F15H_PERF_CTL) >> 1;
+		return msr - MSR_K7_EVNTSEL0;
+	case X86_VENDOR_INTEL:
+		if (cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON))
+			return msr - MSR_ARCH_PERFMON_EVENTSEL0;
+
+		switch (boot_cpu_data.x86) {
+		case 6:
+			return msr - MSR_P6_EVNTSEL0;
+		case 11:
+			return msr - MSR_KNC_EVNTSEL0;
+		case 15:
+			return msr - MSR_P4_BSU_ESCR0;
+		}
+	}
+	return 0;
+
+}
+
+/* checks for a bit availability (hack for oprofile) */
+int avail_to_resrv_perfctr_nmi_bit(unsigned int counter)
+{
+	BUG_ON(counter > NMI_MAX_COUNTER_BITS);
+
+	return !test_bit(counter, perfctr_nmi_owner);
+}
+EXPORT_SYMBOL(avail_to_resrv_perfctr_nmi_bit);
+
+int reserve_perfctr_nmi(unsigned int msr)
+{
+	unsigned int counter;
+
+	counter = nmi_perfctr_msr_to_bit(msr);
+	/* register not managed by the allocator? */
+	if (counter > NMI_MAX_COUNTER_BITS)
+		return 1;
+
+	if (!test_and_set_bit(counter, perfctr_nmi_owner))
+		return 1;
+	return 0;
+}
+EXPORT_SYMBOL(reserve_perfctr_nmi);
+
+void release_perfctr_nmi(unsigned int msr)
+{
+	unsigned int counter;
+
+	counter = nmi_perfctr_msr_to_bit(msr);
+	/* register not managed by the allocator? */
+	if (counter > NMI_MAX_COUNTER_BITS)
+		return;
+
+	clear_bit(counter, perfctr_nmi_owner);
+}
+EXPORT_SYMBOL(release_perfctr_nmi);
+
+int reserve_evntsel_nmi(unsigned int msr)
+{
+	unsigned int counter;
+
+	counter = nmi_evntsel_msr_to_bit(msr);
+	/* register not managed by the allocator? */
+	if (counter > NMI_MAX_COUNTER_BITS)
+		return 1;
+
+	if (!test_and_set_bit(counter, evntsel_nmi_owner))
+		return 1;
+	return 0;
+}
+EXPORT_SYMBOL(reserve_evntsel_nmi);
+
+void release_evntsel_nmi(unsigned int msr)
+{
+	unsigned int counter;
+
+	counter = nmi_evntsel_msr_to_bit(msr);
+	/* register not managed by the allocator? */
+	if (counter > NMI_MAX_COUNTER_BITS)
+		return;
+
+	clear_bit(counter, evntsel_nmi_owner);
+}
+EXPORT_SYMBOL(release_evntsel_nmi);