perfcounters: add fixed-mode PMC enumeration

Enumerate fixed-mode PMCs based on CPUID, and feed that into the
perfcounter code.

Does not use fixed-mode PMCs yet.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 40 insertions, 6 deletions

diff --git a/arch/x86/include/asm/perf_counter.h b/arch/x86/include/asm/perf_counter.h
index dd5a4a559e2d..945a315e6d62 100644
--- a/arch/x86/include/asm/perf_counter.h
+++ b/arch/x86/include/asm/perf_counter.h
@@ -41,6 +41,29 @@ union cpuid10_eax {
         unsigned int full;
 };
 
+union cpuid10_edx {
+        struct {
+                unsigned int num_counters_fixed:4;
+                unsigned int reserved:28;
+        } split;
+        unsigned int full;
+};
+
+
+/*
+ * Fixed-purpose performance counters:
+ */
+
+/* Instr_Retired.Any: */
+#define MSR_ARCH_PERFMON_FIXED_CTR0                     0x309
+
+/* CPU_CLK_Unhalted.Core: */
+#define MSR_ARCH_PERFMON_FIXED_CTR1                     0x30a
+
+/* CPU_CLK_Unhalted.Ref: */
+#define MSR_ARCH_PERFMON_FIXED_CTR2                     0x30b
+
+
 #ifdef CONFIG_PERF_COUNTERS
 extern void init_hw_perf_counters(void);
 extern void perf_counters_lapic_init(int nmi);
diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c
index fc3af8688232..2fca50c45979 100644
--- a/arch/x86/kernel/cpu/perf_counter.c
+++ b/arch/x86/kernel/cpu/perf_counter.c
@@ -27,6 +27,8 @@ static bool perf_counters_initialized __read_mostly;
 static int nr_hw_counters __read_mostly;
 static u32 perf_counter_mask __read_mostly;
 
+static int nr_hw_counters_fixed __read_mostly;
+
 struct cpu_hw_counters {
         struct perf_counter     *generic[X86_PMC_MAX_GENERIC];
         unsigned long           used[BITS_TO_LONGS(X86_PMC_MAX_GENERIC)];
@@ -519,8 +521,9 @@ static __read_mostly struct notifier_block perf_counter_nmi_notifier = {
 void __init init_hw_perf_counters(void)
 {
         union cpuid10_eax eax;
-        unsigned int unused;
         unsigned int ebx;
+        unsigned int unused;
+        union cpuid10_edx edx;
 
         if (!cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON))
                 return;
@@ -529,14 +532,14 @@ void __init init_hw_perf_counters(void)
          * Check whether the Architectural PerfMon supports
          * Branch Misses Retired Event or not.
          */
-        cpuid(10, &(eax.full), &ebx, &unused, &unused);
+        cpuid(10, &eax.full, &ebx, &unused, &edx.full);
         if (eax.split.mask_length <= ARCH_PERFMON_BRANCH_MISSES_RETIRED)
                 return;
 
         printk(KERN_INFO "Intel Performance Monitoring support detected.\n");
 
-        printk(KERN_INFO "... version:      %d\n", eax.split.version_id);
-        printk(KERN_INFO "... num_counters: %d\n", eax.split.num_counters);
+        printk(KERN_INFO "... version:         %d\n", eax.split.version_id);
+        printk(KERN_INFO "... num counters:    %d\n", eax.split.num_counters);
         nr_hw_counters = eax.split.num_counters;
         if (nr_hw_counters > X86_PMC_MAX_GENERIC) {
                 nr_hw_counters = X86_PMC_MAX_GENERIC;
@@ -546,8 +549,16 @@ void __init init_hw_perf_counters(void)
         perf_counter_mask = (1 << nr_hw_counters) - 1;
         perf_max_counters = nr_hw_counters;
 
-        printk(KERN_INFO "... bit_width:    %d\n", eax.split.bit_width);
-        printk(KERN_INFO "... mask_length:  %d\n", eax.split.mask_length);
+        printk(KERN_INFO "... bit width:       %d\n", eax.split.bit_width);
+        printk(KERN_INFO "... mask length:     %d\n", eax.split.mask_length);
+
+        nr_hw_counters_fixed = edx.split.num_counters_fixed;
+        if (nr_hw_counters_fixed > X86_PMC_MAX_FIXED) {
+                nr_hw_counters_fixed = X86_PMC_MAX_FIXED;
+                WARN(1, KERN_ERR "hw perf counters fixed %d > max(%d), clipping!",
+                        nr_hw_counters_fixed, X86_PMC_MAX_FIXED);
+        }
+        printk(KERN_INFO "... fixed counters:  %d\n", nr_hw_counters_fixed);
 
         perf_counters_initialized = true;