perf counters: hw driver API

Impact: restructure code, introduce hw_ops driver abstraction

Introduce this abstraction to handle counter details:

 struct hw_perf_counter_ops {
	void (*hw_perf_counter_enable)	(struct perf_counter *counter);
	void (*hw_perf_counter_disable)	(struct perf_counter *counter);
	void (*hw_perf_counter_read)	(struct perf_counter *counter);
 };

This will be useful to support assymetric hw details, and it will also
be useful to implement "software counters". (Counters that count kernel
managed sw events such as pagefaults, context-switches, wall-clock time
or task-local time.)

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

1 files changed, 27 insertions, 10 deletions

diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c
index 54b4ad0cce6..718b635dece 100644
--- a/arch/x86/kernel/cpu/perf_counter.c
+++ b/arch/x86/kernel/cpu/perf_counter.c
@@ -56,7 +56,7 @@ const int max_intel_perfmon_events = ARRAY_SIZE(intel_perfmon_event_map);
 /*
  * Setup the hardware configuration for a given hw_event_type
  */
-int hw_perf_counter_init(struct perf_counter *counter)
+static int __hw_perf_counter_init(struct perf_counter *counter)
 {
         struct perf_counter_hw_event *hw_event = &counter->hw_event;
         struct hw_perf_counter *hwc = &counter->hw;
@@ -135,7 +135,7 @@ u64 hw_perf_disable_all(void)
 EXPORT_SYMBOL_GPL(hw_perf_disable_all);
 
 static inline void
-__hw_perf_counter_disable(struct hw_perf_counter *hwc, unsigned int idx)
+__x86_perf_counter_disable(struct hw_perf_counter *hwc, unsigned int idx)
 {
         wrmsr(hwc->config_base + idx, hwc->config, 0);
 }
@@ -149,13 +149,13 @@ static void __hw_perf_counter_set_period(struct hw_perf_counter *hwc, int idx)
         wrmsr(hwc->counter_base + idx, hwc->next_count, 0);
 }
 
-static void __hw_perf_counter_enable(struct hw_perf_counter *hwc, int idx)
+static void __x86_perf_counter_enable(struct hw_perf_counter *hwc, int idx)
 {
         wrmsr(hwc->config_base + idx,
               hwc->config | ARCH_PERFMON_EVENTSEL0_ENABLE, 0);
 }
 
-void hw_perf_counter_enable(struct perf_counter *counter)
+static void x86_perf_counter_enable(struct perf_counter *counter)
 {
         struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
         struct hw_perf_counter *hwc = &counter->hw;
@@ -170,12 +170,12 @@ void hw_perf_counter_enable(struct perf_counter *counter)
 
         perf_counters_lapic_init(hwc->nmi);
 
-        __hw_perf_counter_disable(hwc, idx);
+        __x86_perf_counter_disable(hwc, idx);
 
         cpuc->counters[idx] = counter;
 
         __hw_perf_counter_set_period(hwc, idx);
-        __hw_perf_counter_enable(hwc, idx);
+        __x86_perf_counter_enable(hwc, idx);
 }
 
 #ifdef CONFIG_X86_64
@@ -282,20 +282,20 @@ void perf_counter_print_debug(void)
         local_irq_enable();
 }
 
-void hw_perf_counter_disable(struct perf_counter *counter)
+static void x86_perf_counter_disable(struct perf_counter *counter)
 {
         struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
         struct hw_perf_counter *hwc = &counter->hw;
         unsigned int idx = hwc->idx;
 
-        __hw_perf_counter_disable(hwc, idx);
+        __x86_perf_counter_disable(hwc, idx);
 
         clear_bit(idx, cpuc->used);
         cpuc->counters[idx] = NULL;
         __hw_perf_save_counter(counter, hwc, idx);
 }
 
-void hw_perf_counter_read(struct perf_counter *counter)
+static void x86_perf_counter_read(struct perf_counter *counter)
 {
         struct hw_perf_counter *hwc = &counter->hw;
         unsigned long addr = hwc->counter_base + hwc->idx;
@@ -342,7 +342,7 @@ static void perf_save_and_restart(struct perf_counter *counter)
         __hw_perf_counter_set_period(hwc, idx);
 
         if (pmc_ctrl & ARCH_PERFMON_EVENTSEL0_ENABLE)
-                __hw_perf_counter_enable(hwc, idx);
+                __x86_perf_counter_enable(hwc, idx);
 }
 
 static void
@@ -572,3 +572,20 @@ void __init init_hw_perf_counters(void)
 
         perf_counters_initialized = true;
 }
+
+static struct hw_perf_counter_ops x86_perf_counter_ops = {
+        .hw_perf_counter_enable         = x86_perf_counter_enable,
+        .hw_perf_counter_disable        = x86_perf_counter_disable,
+        .hw_perf_counter_read           = x86_perf_counter_read,
+};
+
+struct hw_perf_counter_ops *hw_perf_counter_init(struct perf_counter *counter)
+{
+        int err;
+
+        err = __hw_perf_counter_init(counter);
+        if (err)
+                return NULL;
+
+        return &x86_perf_counter_ops;
+}