sparc64: Initial hw perf counter support.
Only supports one simple counter and only UltraSPARC-IIIi chips.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc/include/asm/nmi.h b/arch/sparc/include/asm/nmi.h
index c7d11e4..72e6500 100644
--- a/arch/sparc/include/asm/nmi.h
+++ b/arch/sparc/include/asm/nmi.h
@@ -7,4 +7,7 @@
extern atomic_t nmi_active;
+extern void start_nmi_watchdog(void *unused);
+extern void stop_nmi_watchdog(void *unused);
+
#endif /* __NMI_H */
diff --git a/arch/sparc/include/asm/perf_counter.h b/arch/sparc/include/asm/perf_counter.h
index 38d6445..5d7a8ca 100644
--- a/arch/sparc/include/asm/perf_counter.h
+++ b/arch/sparc/include/asm/perf_counter.h
@@ -5,4 +5,10 @@
#define PERF_COUNTER_INDEX_OFFSET 0
+#ifdef CONFIG_PERF_COUNTERS
+extern void init_hw_perf_counters(void);
+#else
+static inline void init_hw_perf_counters(void) { }
+#endif
+
#endif
diff --git a/arch/sparc/kernel/Makefile b/arch/sparc/kernel/Makefile
index b004175..f96dc57 100644
--- a/arch/sparc/kernel/Makefile
+++ b/arch/sparc/kernel/Makefile
@@ -103,3 +103,6 @@
obj-$(CONFIG_AUDIT) += audit.o
audit--$(CONFIG_AUDIT) := compat_audit.o
obj-$(CONFIG_COMPAT) += $(audit--y)
+
+pc--$(CONFIG_PERF_COUNTERS) := perf_counter.o
+obj-$(CONFIG_SPARC64) += $(pc--y)
diff --git a/arch/sparc/kernel/nmi.c b/arch/sparc/kernel/nmi.c
index 7de19dd..391a6ed 100644
--- a/arch/sparc/kernel/nmi.c
+++ b/arch/sparc/kernel/nmi.c
@@ -19,6 +19,7 @@
#include <linux/delay.h>
#include <linux/smp.h>
+#include <asm/perf_counter.h>
#include <asm/ptrace.h>
#include <asm/local.h>
#include <asm/pcr.h>
@@ -156,7 +157,7 @@
atomic_dec(&nmi_active);
}
-static void stop_nmi_watchdog(void *unused)
+void stop_nmi_watchdog(void *unused)
{
pcr_ops->write(PCR_PIC_PRIV);
__get_cpu_var(wd_enabled) = 0;
@@ -210,7 +211,7 @@
return err;
}
-static void start_nmi_watchdog(void *unused)
+void start_nmi_watchdog(void *unused)
{
__get_cpu_var(wd_enabled) = 1;
atomic_inc(&nmi_active);
@@ -263,6 +264,9 @@
atomic_set(&nmi_active, -1);
}
}
+ if (!err)
+ init_hw_perf_counters();
+
return err;
}
diff --git a/arch/sparc/kernel/perf_counter.c b/arch/sparc/kernel/perf_counter.c
new file mode 100644
index 0000000..f2c7814
--- /dev/null
+++ b/arch/sparc/kernel/perf_counter.c
@@ -0,0 +1,520 @@
+/* Performance counter support for sparc64.
+ *
+ * Copyright (C) 2009 David S. Miller <davem@davemloft.net>
+ *
+ * This code is based almost entirely upon the x86 perf counter
+ * code, which is:
+ *
+ * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
+ * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
+ * Copyright (C) 2009 Jaswinder Singh Rajput
+ * Copyright (C) 2009 Advanced Micro Devices, Inc., Robert Richter
+ * Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
+ */
+
+#include <linux/perf_counter.h>
+#include <linux/kprobes.h>
+#include <linux/kernel.h>
+#include <linux/kdebug.h>
+#include <linux/mutex.h>
+
+#include <asm/cpudata.h>
+#include <asm/atomic.h>
+#include <asm/nmi.h>
+#include <asm/pcr.h>
+
+/* Sparc64 chips have two performance counters, 32-bits each, with
+ * overflow interrupts generated on transition from 0xffffffff to 0.
+ * The counters are accessed in one go using a 64-bit register.
+ *
+ * Both counters are controlled using a single control register. The
+ * only way to stop all sampling is to clear all of the context (user,
+ * supervisor, hypervisor) sampling enable bits. But these bits apply
+ * to both counters, thus the two counters can't be enabled/disabled
+ * individually.
+ *
+ * The control register has two event fields, one for each of the two
+ * counters. It's thus nearly impossible to have one counter going
+ * while keeping the other one stopped. Therefore it is possible to
+ * get overflow interrupts for counters not currently "in use" and
+ * that condition must be checked in the overflow interrupt handler.
+ *
+ * So we use a hack, in that we program inactive counters with the
+ * "sw_count0" and "sw_count1" events. These count how many times
+ * the instruction "sethi %hi(0xfc000), %g0" is executed. It's an
+ * unusual way to encode a NOP and therefore will not trigger in
+ * normal code.
+ */
+
+#define MAX_HWCOUNTERS 2
+#define MAX_PERIOD ((1UL << 32) - 1)
+
+#define PIC_UPPER_INDEX 0
+#define PIC_LOWER_INDEX 1
+
+#define PIC_UPPER_NOP 0x1c
+#define PIC_LOWER_NOP 0x14
+
+struct cpu_hw_counters {
+ struct perf_counter *counters[MAX_HWCOUNTERS];
+ unsigned long used_mask[BITS_TO_LONGS(MAX_HWCOUNTERS)];
+ unsigned long active_mask[BITS_TO_LONGS(MAX_HWCOUNTERS)];
+ int enabled;
+};
+DEFINE_PER_CPU(struct cpu_hw_counters, cpu_hw_counters) = { .enabled = 1, };
+
+struct perf_event_map {
+ u16 encoding;
+ u8 pic_mask;
+#define PIC_NONE 0x00
+#define PIC_UPPER 0x01
+#define PIC_LOWER 0x02
+};
+
+struct sparc_pmu {
+ const struct perf_event_map *(*event_map)(int);
+ int max_events;
+ int upper_shift;
+ int lower_shift;
+ int event_mask;
+};
+
+static const struct perf_event_map ultra3i_perfmon_event_map[] = {
+ [PERF_COUNT_HW_CPU_CYCLES] = { 0x0000, PIC_UPPER | PIC_LOWER },
+ [PERF_COUNT_HW_INSTRUCTIONS] = { 0x0001, PIC_UPPER | PIC_LOWER },
+ [PERF_COUNT_HW_CACHE_REFERENCES] = { 0x0009, PIC_LOWER },
+ [PERF_COUNT_HW_CACHE_MISSES] = { 0x0009, PIC_UPPER },
+};
+
+static const struct perf_event_map *ultra3i_event_map(int event)
+{
+ return &ultra3i_perfmon_event_map[event];
+}
+
+static const struct sparc_pmu ultra3i_pmu = {
+ .event_map = ultra3i_event_map,
+ .max_events = ARRAY_SIZE(ultra3i_perfmon_event_map),
+ .upper_shift = 11,
+ .lower_shift = 4,
+ .event_mask = 0x3f,
+};
+
+static const struct sparc_pmu *sparc_pmu __read_mostly;
+
+static u64 event_encoding(u64 event, int idx)
+{
+ if (idx == PIC_UPPER_INDEX)
+ event <<= sparc_pmu->upper_shift;
+ else
+ event <<= sparc_pmu->lower_shift;
+ return event;
+}
+
+static u64 mask_for_index(int idx)
+{
+ return event_encoding(sparc_pmu->event_mask, idx);
+}
+
+static u64 nop_for_index(int idx)
+{
+ return event_encoding(idx == PIC_UPPER_INDEX ?
+ PIC_UPPER_NOP : PIC_LOWER_NOP, idx);
+}
+
+static inline void sparc_pmu_enable_counter(struct hw_perf_counter *hwc,
+ int idx)
+{
+ u64 val, mask = mask_for_index(idx);
+
+ val = pcr_ops->read();
+ pcr_ops->write((val & ~mask) | hwc->config);
+}
+
+static inline void sparc_pmu_disable_counter(struct hw_perf_counter *hwc,
+ int idx)
+{
+ u64 mask = mask_for_index(idx);
+ u64 nop = nop_for_index(idx);
+ u64 val = pcr_ops->read();
+
+ pcr_ops->write((val & ~mask) | nop);
+}
+
+void hw_perf_enable(void)
+{
+ struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
+ u64 val;
+ int i;
+
+ if (cpuc->enabled)
+ return;
+
+ cpuc->enabled = 1;
+ barrier();
+
+ val = pcr_ops->read();
+
+ for (i = 0; i < MAX_HWCOUNTERS; i++) {
+ struct perf_counter *cp = cpuc->counters[i];
+ struct hw_perf_counter *hwc;
+
+ if (!cp)
+ continue;
+ hwc = &cp->hw;
+ val |= hwc->config_base;
+ }
+
+ pcr_ops->write(val);
+}
+
+void hw_perf_disable(void)
+{
+ struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
+ u64 val;
+
+ if (!cpuc->enabled)
+ return;
+
+ cpuc->enabled = 0;
+
+ val = pcr_ops->read();
+ val &= ~(PCR_UTRACE | PCR_STRACE);
+ pcr_ops->write(val);
+}
+
+static u32 read_pmc(int idx)
+{
+ u64 val;
+
+ read_pic(val);
+ if (idx == PIC_UPPER_INDEX)
+ val >>= 32;
+
+ return val & 0xffffffff;
+}
+
+static void write_pmc(int idx, u64 val)
+{
+ u64 shift, mask, pic;
+
+ shift = 0;
+ if (idx == PIC_UPPER_INDEX)
+ shift = 32;
+
+ mask = ((u64) 0xffffffff) << shift;
+ val <<= shift;
+
+ read_pic(pic);
+ pic &= ~mask;
+ pic |= val;
+ write_pic(pic);
+}
+
+static int sparc_perf_counter_set_period(struct perf_counter *counter,
+ struct hw_perf_counter *hwc, int idx)
+{
+ s64 left = atomic64_read(&hwc->period_left);
+ s64 period = hwc->sample_period;
+ int ret = 0;
+
+ if (unlikely(left <= -period)) {
+ left = period;
+ atomic64_set(&hwc->period_left, left);
+ hwc->last_period = period;
+ ret = 1;
+ }
+
+ if (unlikely(left <= 0)) {
+ left += period;
+ atomic64_set(&hwc->period_left, left);
+ hwc->last_period = period;
+ ret = 1;
+ }
+ if (left > MAX_PERIOD)
+ left = MAX_PERIOD;
+
+ atomic64_set(&hwc->prev_count, (u64)-left);
+
+ write_pmc(idx, (u64)(-left) & 0xffffffff);
+
+ perf_counter_update_userpage(counter);
+
+ return ret;
+}
+
+static int sparc_pmu_enable(struct perf_counter *counter)
+{
+ struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
+ struct hw_perf_counter *hwc = &counter->hw;
+ int idx = hwc->idx;
+
+ if (test_and_set_bit(idx, cpuc->used_mask))
+ return -EAGAIN;
+
+ sparc_pmu_disable_counter(hwc, idx);
+
+ cpuc->counters[idx] = counter;
+ set_bit(idx, cpuc->active_mask);
+
+ sparc_perf_counter_set_period(counter, hwc, idx);
+ sparc_pmu_enable_counter(hwc, idx);
+ perf_counter_update_userpage(counter);
+ return 0;
+}
+
+static u64 sparc_perf_counter_update(struct perf_counter *counter,
+ struct hw_perf_counter *hwc, int idx)
+{
+ int shift = 64 - 32;
+ u64 prev_raw_count, new_raw_count;
+ s64 delta;
+
+again:
+ prev_raw_count = atomic64_read(&hwc->prev_count);
+ new_raw_count = read_pmc(idx);
+
+ if (atomic64_cmpxchg(&hwc->prev_count, prev_raw_count,
+ new_raw_count) != prev_raw_count)
+ goto again;
+
+ delta = (new_raw_count << shift) - (prev_raw_count << shift);
+ delta >>= shift;
+
+ atomic64_add(delta, &counter->count);
+ atomic64_sub(delta, &hwc->period_left);
+
+ return new_raw_count;
+}
+
+static void sparc_pmu_disable(struct perf_counter *counter)
+{
+ struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
+ struct hw_perf_counter *hwc = &counter->hw;
+ int idx = hwc->idx;
+
+ clear_bit(idx, cpuc->active_mask);
+ sparc_pmu_disable_counter(hwc, idx);
+
+ barrier();
+
+ sparc_perf_counter_update(counter, hwc, idx);
+ cpuc->counters[idx] = NULL;
+ clear_bit(idx, cpuc->used_mask);
+
+ perf_counter_update_userpage(counter);
+}
+
+static void sparc_pmu_read(struct perf_counter *counter)
+{
+ struct hw_perf_counter *hwc = &counter->hw;
+ sparc_perf_counter_update(counter, hwc, hwc->idx);
+}
+
+static void sparc_pmu_unthrottle(struct perf_counter *counter)
+{
+ struct hw_perf_counter *hwc = &counter->hw;
+ sparc_pmu_enable_counter(hwc, hwc->idx);
+}
+
+static atomic_t active_counters = ATOMIC_INIT(0);
+static DEFINE_MUTEX(pmc_grab_mutex);
+
+void perf_counter_grab_pmc(void)
+{
+ if (atomic_inc_not_zero(&active_counters))
+ return;
+
+ mutex_lock(&pmc_grab_mutex);
+ if (atomic_read(&active_counters) == 0) {
+ if (atomic_read(&nmi_active) > 0) {
+ on_each_cpu(stop_nmi_watchdog, NULL, 1);
+ BUG_ON(atomic_read(&nmi_active) != 0);
+ }
+ atomic_inc(&active_counters);
+ }
+ mutex_unlock(&pmc_grab_mutex);
+}
+
+void perf_counter_release_pmc(void)
+{
+ if (atomic_dec_and_mutex_lock(&active_counters, &pmc_grab_mutex)) {
+ if (atomic_read(&nmi_active) == 0)
+ on_each_cpu(start_nmi_watchdog, NULL, 1);
+ mutex_unlock(&pmc_grab_mutex);
+ }
+}
+
+static void hw_perf_counter_destroy(struct perf_counter *counter)
+{
+ perf_counter_release_pmc();
+}
+
+static int __hw_perf_counter_init(struct perf_counter *counter)
+{
+ struct perf_counter_attr *attr = &counter->attr;
+ struct hw_perf_counter *hwc = &counter->hw;
+ const struct perf_event_map *pmap;
+ u64 enc;
+
+ if (atomic_read(&nmi_active) < 0)
+ return -ENODEV;
+
+ if (attr->type != PERF_TYPE_HARDWARE)
+ return -EOPNOTSUPP;
+
+ if (attr->config >= sparc_pmu->max_events)
+ return -EINVAL;
+
+ perf_counter_grab_pmc();
+ counter->destroy = hw_perf_counter_destroy;
+
+ /* We save the enable bits in the config_base. So to
+ * turn off sampling just write 'config', and to enable
+ * things write 'config | config_base'.
+ */
+ hwc->config_base = 0;
+ if (!attr->exclude_user)
+ hwc->config_base |= PCR_UTRACE;
+ if (!attr->exclude_kernel)
+ hwc->config_base |= PCR_STRACE;
+
+ if (!hwc->sample_period) {
+ hwc->sample_period = MAX_PERIOD;
+ hwc->last_period = hwc->sample_period;
+ atomic64_set(&hwc->period_left, hwc->sample_period);
+ }
+
+ pmap = sparc_pmu->event_map(attr->config);
+
+ enc = pmap->encoding;
+ if (pmap->pic_mask & PIC_UPPER) {
+ hwc->idx = PIC_UPPER_INDEX;
+ enc <<= sparc_pmu->upper_shift;
+ } else {
+ hwc->idx = PIC_LOWER_INDEX;
+ enc <<= sparc_pmu->lower_shift;
+ }
+
+ hwc->config |= enc;
+ return 0;
+}
+
+static const struct pmu pmu = {
+ .enable = sparc_pmu_enable,
+ .disable = sparc_pmu_disable,
+ .read = sparc_pmu_read,
+ .unthrottle = sparc_pmu_unthrottle,
+};
+
+const struct pmu *hw_perf_counter_init(struct perf_counter *counter)
+{
+ int err = __hw_perf_counter_init(counter);
+
+ if (err)
+ return ERR_PTR(err);
+ return &pmu;
+}
+
+void perf_counter_print_debug(void)
+{
+ unsigned long flags;
+ u64 pcr, pic;
+ int cpu;
+
+ if (!sparc_pmu)
+ return;
+
+ local_irq_save(flags);
+
+ cpu = smp_processor_id();
+
+ pcr = pcr_ops->read();
+ read_pic(pic);
+
+ pr_info("\n");
+ pr_info("CPU#%d: PCR[%016llx] PIC[%016llx]\n",
+ cpu, pcr, pic);
+
+ local_irq_restore(flags);
+}
+
+static int __kprobes perf_counter_nmi_handler(struct notifier_block *self,
+ unsigned long cmd, void *__args)
+{
+ struct die_args *args = __args;
+ struct perf_sample_data data;
+ struct cpu_hw_counters *cpuc;
+ struct pt_regs *regs;
+ int idx;
+
+ if (!atomic_read(&active_counters))
+ return NOTIFY_DONE;
+
+ switch (cmd) {
+ case DIE_NMI:
+ break;
+
+ default:
+ return NOTIFY_DONE;
+ }
+
+ regs = args->regs;
+
+ data.regs = regs;
+ data.addr = 0;
+
+ cpuc = &__get_cpu_var(cpu_hw_counters);
+ for (idx = 0; idx < MAX_HWCOUNTERS; idx++) {
+ struct perf_counter *counter = cpuc->counters[idx];
+ struct hw_perf_counter *hwc;
+ u64 val;
+
+ if (!test_bit(idx, cpuc->active_mask))
+ continue;
+ hwc = &counter->hw;
+ val = sparc_perf_counter_update(counter, hwc, idx);
+ if (val & (1ULL << 31))
+ continue;
+
+ data.period = counter->hw.last_period;
+ if (!sparc_perf_counter_set_period(counter, hwc, idx))
+ continue;
+
+ if (perf_counter_overflow(counter, 1, &data))
+ sparc_pmu_disable_counter(hwc, idx);
+ }
+
+ return NOTIFY_STOP;
+}
+
+static __read_mostly struct notifier_block perf_counter_nmi_notifier = {
+ .notifier_call = perf_counter_nmi_handler,
+};
+
+static bool __init supported_pmu(void)
+{
+ if (!strcmp(sparc_pmu_type, "ultra3i")) {
+ sparc_pmu = &ultra3i_pmu;
+ return true;
+ }
+ return false;
+}
+
+void __init init_hw_perf_counters(void)
+{
+ pr_info("Performance counters: ");
+
+ if (!supported_pmu()) {
+ pr_cont("No support for PMU type '%s'\n", sparc_pmu_type);
+ return;
+ }
+
+ pr_cont("Supported PMU type is '%s'\n", sparc_pmu_type);
+
+ /* All sparc64 PMUs currently have 2 counters. But this simple
+ * driver only supports one active counter at a time.
+ */
+ perf_max_counters = 1;
+
+ register_die_notifier(&perf_counter_nmi_notifier);
+}