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Subject[PATCH v3 38/44] metag: Perf
Date
Add Perf support for metag.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
---
arch/metag/Kconfig | 1 +
arch/metag/include/asm/perf_event.h | 4 +
arch/metag/kernel/Makefile | 2 +
arch/metag/kernel/perf/Makefile | 3 +
arch/metag/kernel/perf/perf_event.c | 867 +++++++++++++++++++++++++++++++++++
arch/metag/kernel/perf/perf_event.h | 106 +++++
arch/metag/kernel/perf_callchain.c | 96 ++++
7 files changed, 1079 insertions(+), 0 deletions(-)
create mode 100644 arch/metag/include/asm/perf_event.h
create mode 100644 arch/metag/kernel/perf/Makefile
create mode 100644 arch/metag/kernel/perf/perf_event.c
create mode 100644 arch/metag/kernel/perf/perf_event.h
create mode 100644 arch/metag/kernel/perf_callchain.c

diff --git a/arch/metag/Kconfig b/arch/metag/Kconfig
index a3e9d5b..d60de2b 100644
--- a/arch/metag/Kconfig
+++ b/arch/metag/Kconfig
@@ -20,6 +20,7 @@ config METAG
select HAVE_MEMBLOCK
select HAVE_MEMBLOCK_NODE_MAP
select HAVE_MOD_ARCH_SPECIFIC
+ select HAVE_PERF_EVENTS
select HAVE_SYSCALL_TRACEPOINTS
select IRQ_DOMAIN
select MODULES_USE_ELF_RELA
diff --git a/arch/metag/include/asm/perf_event.h b/arch/metag/include/asm/perf_event.h
new file mode 100644
index 0000000..105bbff
--- /dev/null
+++ b/arch/metag/include/asm/perf_event.h
@@ -0,0 +1,4 @@
+#ifndef __ASM_METAG_PERF_EVENT_H
+#define __ASM_METAG_PERF_EVENT_H
+
+#endif /* __ASM_METAG_PERF_EVENT_H */
diff --git a/arch/metag/kernel/Makefile b/arch/metag/kernel/Makefile
index e985d0c..a5e4ba6 100644
--- a/arch/metag/kernel/Makefile
+++ b/arch/metag/kernel/Makefile
@@ -25,6 +25,8 @@ obj-y += topology.o
obj-y += traps.o
obj-y += user_gateway.o

+obj-$(CONFIG_PERF_EVENTS) += perf/
+
obj-$(CONFIG_METAG_COREMEM) += coremem.o
obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o
obj-$(CONFIG_FUNCTION_TRACER) += ftrace_stub.o
diff --git a/arch/metag/kernel/perf/Makefile b/arch/metag/kernel/perf/Makefile
new file mode 100644
index 0000000..b158cb2
--- /dev/null
+++ b/arch/metag/kernel/perf/Makefile
@@ -0,0 +1,3 @@
+# Makefile for performance event core
+
+obj-y += perf_event.o
diff --git a/arch/metag/kernel/perf/perf_event.c b/arch/metag/kernel/perf/perf_event.c
new file mode 100644
index 0000000..25b02022
--- /dev/null
+++ b/arch/metag/kernel/perf/perf_event.c
@@ -0,0 +1,867 @@
+/*
+ * Meta performance counter support.
+ * Copyright (C) 2012 Imagination Technologies Ltd
+ *
+ * This code is based on the sh pmu code:
+ * Copyright (C) 2009 Paul Mundt
+ *
+ * and on the arm pmu code:
+ * Copyright (C) 2009 picoChip Designs, Ltd., James Iles
+ * Copyright (C) 2010 ARM Ltd., Will Deacon <will.deacon@arm.com>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/atomic.h>
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/irqchip/meta.h>
+#include <linux/perf_event.h>
+#include <linux/slab.h>
+
+#include <asm/hwthread.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+
+#include "perf_event.h"
+
+static int _hw_perf_event_init(struct perf_event *);
+static void _hw_perf_event_destroy(struct perf_event *);
+
+/* Determines which core type we are */
+static struct metag_pmu *metag_pmu __read_mostly;
+
+/* Processor specific data */
+static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events);
+
+/* PMU admin */
+const char *perf_pmu_name(void)
+{
+ if (metag_pmu)
+ return metag_pmu->pmu.name;
+
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(perf_pmu_name);
+
+int perf_num_counters(void)
+{
+ if (metag_pmu)
+ return metag_pmu->max_events;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(perf_num_counters);
+
+static inline int metag_pmu_initialised(void)
+{
+ return !!metag_pmu;
+}
+
+static void release_pmu_hardware(void)
+{
+ int irq;
+ unsigned int version = (metag_pmu->version &
+ (METAC_ID_MINOR_BITS | METAC_ID_REV_BITS)) >>
+ METAC_ID_REV_S;
+
+ /* Early cores don't have overflow interrupts */
+ if (version < 0x0104)
+ return;
+
+ irq = internal_irq_map(17);
+ if (irq >= 0)
+ free_irq(irq, (void *)1);
+
+ irq = internal_irq_map(16);
+ if (irq >= 0)
+ free_irq(irq, (void *)0);
+}
+
+static int reserve_pmu_hardware(void)
+{
+ int err = 0, irq[2];
+ unsigned int version = (metag_pmu->version &
+ (METAC_ID_MINOR_BITS | METAC_ID_REV_BITS)) >>
+ METAC_ID_REV_S;
+
+ /* Early cores don't have overflow interrupts */
+ if (version < 0x0104)
+ goto out;
+
+ /*
+ * Bit 16 on HWSTATMETA is the interrupt for performance counter 0;
+ * similarly, 17 is the interrupt for performance counter 1.
+ * We can't (yet) interrupt on the cycle counter, because it's a
+ * register, however it holds a 32-bit value as opposed to 24-bit.
+ */
+ irq[0] = internal_irq_map(16);
+ if (irq[0] < 0) {
+ pr_err("unable to map internal IRQ %d\n", 16);
+ goto out;
+ }
+ err = request_irq(irq[0], metag_pmu->handle_irq, IRQF_NOBALANCING,
+ "metagpmu0", (void *)0);
+ if (err) {
+ pr_err("unable to request IRQ%d for metag PMU counters\n",
+ irq[0]);
+ goto out;
+ }
+
+ irq[1] = internal_irq_map(17);
+ if (irq[1] < 0) {
+ pr_err("unable to map internal IRQ %d\n", 17);
+ goto out_irq1;
+ }
+ err = request_irq(irq[1], metag_pmu->handle_irq, IRQF_NOBALANCING,
+ "metagpmu1", (void *)1);
+ if (err) {
+ pr_err("unable to request IRQ%d for metag PMU counters\n",
+ irq[1]);
+ goto out_irq1;
+ }
+
+ return 0;
+
+out_irq1:
+ free_irq(irq[0], (void *)0);
+out:
+ return err;
+}
+
+/* PMU operations */
+static void metag_pmu_enable(struct pmu *pmu)
+{
+}
+
+static void metag_pmu_disable(struct pmu *pmu)
+{
+}
+
+static int metag_pmu_event_init(struct perf_event *event)
+{
+ int err = 0;
+ atomic_t *active_events = &metag_pmu->active_events;
+
+ if (!metag_pmu_initialised()) {
+ err = -ENODEV;
+ goto out;
+ }
+
+ if (has_branch_stack(event))
+ return -EOPNOTSUPP;
+
+ event->destroy = _hw_perf_event_destroy;
+
+ if (!atomic_inc_not_zero(active_events)) {
+ mutex_lock(&metag_pmu->reserve_mutex);
+ if (atomic_read(active_events) == 0)
+ err = reserve_pmu_hardware();
+
+ if (!err)
+ atomic_inc(active_events);
+
+ mutex_unlock(&metag_pmu->reserve_mutex);
+ }
+
+ /* Hardware and caches counters */
+ switch (event->attr.type) {
+ case PERF_TYPE_HARDWARE:
+ case PERF_TYPE_HW_CACHE:
+ err = _hw_perf_event_init(event);
+ break;
+
+ default:
+ return -ENOENT;
+ }
+
+ if (err)
+ event->destroy(event);
+
+out:
+ return err;
+}
+
+void metag_pmu_event_update(struct perf_event *event,
+ struct hw_perf_event *hwc, int idx)
+{
+ u64 prev_raw_count, new_raw_count;
+ s64 delta;
+
+ /*
+ * If this counter is chained, it may be that the previous counter
+ * value has been changed beneath us.
+ *
+ * To get around this, we read and exchange the new raw count, then
+ * add the delta (new - prev) to the generic counter atomically.
+ *
+ * Without interrupts, this is the simplest approach.
+ */
+again:
+ prev_raw_count = local64_read(&hwc->prev_count);
+ new_raw_count = metag_pmu->read(idx);
+
+ if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
+ new_raw_count) != prev_raw_count)
+ goto again;
+
+ /*
+ * Calculate the delta and add it to the counter.
+ */
+ delta = new_raw_count - prev_raw_count;
+
+ local64_add(delta, &event->count);
+}
+
+int metag_pmu_event_set_period(struct perf_event *event,
+ struct hw_perf_event *hwc, int idx)
+{
+ s64 left = local64_read(&hwc->period_left);
+ s64 period = hwc->sample_period;
+ int ret = 0;
+
+ if (unlikely(left <= -period)) {
+ left = period;
+ local64_set(&hwc->period_left, left);
+ hwc->last_period = period;
+ ret = 1;
+ }
+
+ if (unlikely(left <= 0)) {
+ left += period;
+ local64_set(&hwc->period_left, left);
+ hwc->last_period = period;
+ ret = 1;
+ }
+
+ if (left > (s64)metag_pmu->max_period)
+ left = metag_pmu->max_period;
+
+ if (metag_pmu->write)
+ metag_pmu->write(idx, (u64)(-left) & MAX_PERIOD);
+
+ perf_event_update_userpage(event);
+
+ return ret;
+}
+
+static void metag_pmu_start(struct perf_event *event, int flags)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ struct hw_perf_event *hwc = &event->hw;
+ int idx = hwc->idx;
+
+ if (WARN_ON_ONCE(idx == -1))
+ return;
+
+ /*
+ * We always have to reprogram the period, so ignore PERF_EF_RELOAD.
+ */
+ if (flags & PERF_EF_RELOAD)
+ WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
+
+ hwc->state = 0;
+
+ /*
+ * Reset the period.
+ * Some counters can't be stopped (i.e. are core global), so when the
+ * counter was 'stopped' we merely disabled the IRQ. If we don't reset
+ * the period, then we'll either: a) get an overflow too soon;
+ * or b) too late if the overflow happened since disabling.
+ * Obviously, this has little bearing on cores without the overflow
+ * interrupt, as the performance counter resets to zero on write
+ * anyway.
+ */
+ if (metag_pmu->max_period)
+ metag_pmu_event_set_period(event, hwc, hwc->idx);
+ cpuc->events[idx] = event;
+ metag_pmu->enable(hwc, idx);
+}
+
+static void metag_pmu_stop(struct perf_event *event, int flags)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ /*
+ * We should always update the counter on stop; see comment above
+ * why.
+ */
+ if (!(hwc->state & PERF_HES_STOPPED)) {
+ metag_pmu_event_update(event, hwc, hwc->idx);
+ metag_pmu->disable(hwc, hwc->idx);
+ hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
+ }
+}
+
+static int metag_pmu_add(struct perf_event *event, int flags)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ struct hw_perf_event *hwc = &event->hw;
+ int idx = 0, ret = 0;
+
+ perf_pmu_disable(event->pmu);
+
+ /* check whether we're counting instructions */
+ if (hwc->config == 0x100) {
+ if (__test_and_set_bit(METAG_INST_COUNTER,
+ cpuc->used_mask)) {
+ ret = -EAGAIN;
+ goto out;
+ }
+ idx = METAG_INST_COUNTER;
+ } else {
+ /* Check whether we have a spare counter */
+ idx = find_first_zero_bit(cpuc->used_mask,
+ atomic_read(&metag_pmu->active_events));
+ if (idx >= METAG_INST_COUNTER) {
+ ret = -EAGAIN;
+ goto out;
+ }
+
+ __set_bit(idx, cpuc->used_mask);
+ }
+ hwc->idx = idx;
+
+ /* Make sure the counter is disabled */
+ metag_pmu->disable(hwc, idx);
+
+ hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
+ if (flags & PERF_EF_START)
+ metag_pmu_start(event, PERF_EF_RELOAD);
+
+ perf_event_update_userpage(event);
+out:
+ perf_pmu_enable(event->pmu);
+ return ret;
+}
+
+static void metag_pmu_del(struct perf_event *event, int flags)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ struct hw_perf_event *hwc = &event->hw;
+ int idx = hwc->idx;
+
+ WARN_ON(idx < 0);
+ metag_pmu_stop(event, PERF_EF_UPDATE);
+ cpuc->events[idx] = NULL;
+ __clear_bit(idx, cpuc->used_mask);
+
+ perf_event_update_userpage(event);
+}
+
+static void metag_pmu_read(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ /* Don't read disabled counters! */
+ if (hwc->idx < 0)
+ return;
+
+ metag_pmu_event_update(event, hwc, hwc->idx);
+}
+
+static struct pmu pmu = {
+ .pmu_enable = metag_pmu_enable,
+ .pmu_disable = metag_pmu_disable,
+
+ .event_init = metag_pmu_event_init,
+
+ .add = metag_pmu_add,
+ .del = metag_pmu_del,
+ .start = metag_pmu_start,
+ .stop = metag_pmu_stop,
+ .read = metag_pmu_read,
+};
+
+/* Core counter specific functions */
+static const int metag_general_events[] = {
+ [PERF_COUNT_HW_CPU_CYCLES] = 0x03,
+ [PERF_COUNT_HW_INSTRUCTIONS] = 0x100,
+ [PERF_COUNT_HW_CACHE_REFERENCES] = -1,
+ [PERF_COUNT_HW_CACHE_MISSES] = -1,
+ [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = -1,
+ [PERF_COUNT_HW_BRANCH_MISSES] = -1,
+ [PERF_COUNT_HW_BUS_CYCLES] = -1,
+ [PERF_COUNT_HW_STALLED_CYCLES_FRONTEND] = -1,
+ [PERF_COUNT_HW_STALLED_CYCLES_BACKEND] = -1,
+ [PERF_COUNT_HW_REF_CPU_CYCLES] = -1,
+};
+
+static const int metag_pmu_cache_events[C(MAX)][C(OP_MAX)][C(RESULT_MAX)] = {
+ [C(L1D)] = {
+ [C(OP_READ)] = {
+ [C(RESULT_ACCESS)] = 0x08,
+ [C(RESULT_MISS)] = CACHE_OP_UNSUPPORTED,
+ },
+ [C(OP_WRITE)] = {
+ [C(RESULT_ACCESS)] = CACHE_OP_UNSUPPORTED,
+ [C(RESULT_MISS)] = CACHE_OP_UNSUPPORTED,
+ },
+ [C(OP_PREFETCH)] = {
+ [C(RESULT_ACCESS)] = CACHE_OP_UNSUPPORTED,
+ [C(RESULT_MISS)] = CACHE_OP_UNSUPPORTED,
+ },
+ },
+ [C(L1I)] = {
+ [C(OP_READ)] = {
+ [C(RESULT_ACCESS)] = 0x09,
+ [C(RESULT_MISS)] = 0x0a,
+ },
+ [C(OP_WRITE)] = {
+ [C(RESULT_ACCESS)] = CACHE_OP_UNSUPPORTED,
+ [C(RESULT_MISS)] = CACHE_OP_UNSUPPORTED,
+ },
+ [C(OP_PREFETCH)] = {
+ [C(RESULT_ACCESS)] = CACHE_OP_UNSUPPORTED,
+ [C(RESULT_MISS)] = CACHE_OP_UNSUPPORTED,
+ },
+ },
+ [C(LL)] = {
+ [C(OP_READ)] = {
+ [C(RESULT_ACCESS)] = CACHE_OP_UNSUPPORTED,
+ [C(RESULT_MISS)] = CACHE_OP_UNSUPPORTED,
+ },
+ [C(OP_WRITE)] = {
+ [C(RESULT_ACCESS)] = CACHE_OP_UNSUPPORTED,
+ [C(RESULT_MISS)] = CACHE_OP_UNSUPPORTED,
+ },
+ [C(OP_PREFETCH)] = {
+ [C(RESULT_ACCESS)] = CACHE_OP_UNSUPPORTED,
+ [C(RESULT_MISS)] = CACHE_OP_UNSUPPORTED,
+ },
+ },
+ [C(DTLB)] = {
+ [C(OP_READ)] = {
+ [C(RESULT_ACCESS)] = 0xd0,
+ [C(RESULT_MISS)] = 0xd2,
+ },
+ [C(OP_WRITE)] = {
+ [C(RESULT_ACCESS)] = 0xd4,
+ [C(RESULT_MISS)] = 0xd5,
+ },
+ [C(OP_PREFETCH)] = {
+ [C(RESULT_ACCESS)] = CACHE_OP_UNSUPPORTED,
+ [C(RESULT_MISS)] = CACHE_OP_UNSUPPORTED,
+ },
+ },
+ [C(ITLB)] = {
+ [C(OP_READ)] = {
+ [C(RESULT_ACCESS)] = 0xd1,
+ [C(RESULT_MISS)] = 0xd3,
+ },
+ [C(OP_WRITE)] = {
+ [C(RESULT_ACCESS)] = CACHE_OP_UNSUPPORTED,
+ [C(RESULT_MISS)] = CACHE_OP_UNSUPPORTED,
+ },
+ [C(OP_PREFETCH)] = {
+ [C(RESULT_ACCESS)] = CACHE_OP_UNSUPPORTED,
+ [C(RESULT_MISS)] = CACHE_OP_UNSUPPORTED,
+ },
+ },
+ [C(BPU)] = {
+ [C(OP_READ)] = {
+ [C(RESULT_ACCESS)] = CACHE_OP_UNSUPPORTED,
+ [C(RESULT_MISS)] = CACHE_OP_UNSUPPORTED,
+ },
+ [C(OP_WRITE)] = {
+ [C(RESULT_ACCESS)] = CACHE_OP_UNSUPPORTED,
+ [C(RESULT_MISS)] = CACHE_OP_UNSUPPORTED,
+ },
+ [C(OP_PREFETCH)] = {
+ [C(RESULT_ACCESS)] = CACHE_OP_UNSUPPORTED,
+ [C(RESULT_MISS)] = CACHE_OP_UNSUPPORTED,
+ },
+ },
+ [C(NODE)] = {
+ [C(OP_READ)] = {
+ [C(RESULT_ACCESS)] = CACHE_OP_UNSUPPORTED,
+ [C(RESULT_MISS)] = CACHE_OP_UNSUPPORTED,
+ },
+ [C(OP_WRITE)] = {
+ [C(RESULT_ACCESS)] = CACHE_OP_UNSUPPORTED,
+ [C(RESULT_MISS)] = CACHE_OP_UNSUPPORTED,
+ },
+ [C(OP_PREFETCH)] = {
+ [C(RESULT_ACCESS)] = CACHE_OP_UNSUPPORTED,
+ [C(RESULT_MISS)] = CACHE_OP_UNSUPPORTED,
+ },
+ },
+};
+
+
+static void _hw_perf_event_destroy(struct perf_event *event)
+{
+ atomic_t *active_events = &metag_pmu->active_events;
+ struct mutex *pmu_mutex = &metag_pmu->reserve_mutex;
+
+ if (atomic_dec_and_mutex_lock(active_events, pmu_mutex)) {
+ release_pmu_hardware();
+ mutex_unlock(pmu_mutex);
+ }
+}
+
+static int _hw_perf_cache_event(int config, int *evp)
+{
+ unsigned long type, op, result;
+ int ev;
+
+ if (!metag_pmu->cache_events)
+ return -EINVAL;
+
+ /* Unpack config */
+ type = config & 0xff;
+ op = (config >> 8) & 0xff;
+ result = (config >> 16) & 0xff;
+
+ if (type >= PERF_COUNT_HW_CACHE_MAX ||
+ op >= PERF_COUNT_HW_CACHE_OP_MAX ||
+ result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
+ return -EINVAL;
+
+ ev = (*metag_pmu->cache_events)[type][op][result];
+ if (ev == 0)
+ return -EOPNOTSUPP;
+ if (ev == -1)
+ return -EINVAL;
+ *evp = ev;
+ return 0;
+}
+
+static int _hw_perf_event_init(struct perf_event *event)
+{
+ struct perf_event_attr *attr = &event->attr;
+ struct hw_perf_event *hwc = &event->hw;
+ int mapping = 0, err;
+
+ switch (attr->type) {
+ case PERF_TYPE_HARDWARE:
+ if (attr->config >= PERF_COUNT_HW_MAX)
+ return -EINVAL;
+
+ mapping = metag_pmu->event_map(attr->config);
+ break;
+
+ case PERF_TYPE_HW_CACHE:
+ err = _hw_perf_cache_event(attr->config, &mapping);
+ if (err)
+ return err;
+ break;
+ }
+
+ /* Return early if the event is unsupported */
+ if (mapping == -1)
+ return -EINVAL;
+
+ /*
+ * Early cores have "limited" counters - they have no overflow
+ * interrupts - and so are unable to do sampling without extra work
+ * and timer assistance.
+ */
+ if (metag_pmu->max_period == 0) {
+ if (hwc->sample_period)
+ return -EINVAL;
+ }
+
+ /*
+ * Don't assign an index until the event is placed into the hardware.
+ * -1 signifies that we're still deciding where to put it. On SMP
+ * systems each core has its own set of counters, so we can't do any
+ * constraint checking yet.
+ */
+ hwc->idx = -1;
+
+ /* Store the event encoding */
+ hwc->config |= (unsigned long)mapping;
+
+ /*
+ * For non-sampling runs, limit the sample_period to half of the
+ * counter width. This way, the new counter value should be less
+ * likely to overtake the previous one (unless there are IRQ latency
+ * issues...)
+ */
+ if (metag_pmu->max_period) {
+ if (!hwc->sample_period) {
+ hwc->sample_period = metag_pmu->max_period >> 1;
+ hwc->last_period = hwc->sample_period;
+ local64_set(&hwc->period_left, hwc->sample_period);
+ }
+ }
+
+ return 0;
+}
+
+static void metag_pmu_enable_counter(struct hw_perf_event *event, int idx)
+{
+ struct cpu_hw_events *events = &__get_cpu_var(cpu_hw_events);
+ unsigned int config = event->config;
+ unsigned int tmp = config & 0xf0;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&events->pmu_lock, flags);
+
+ /*
+ * Check if we're enabling the instruction counter (index of
+ * MAX_HWEVENTS - 1)
+ */
+ if (METAG_INST_COUNTER == idx) {
+ tmp = 0;
+ WARN_ONCE((config != 0x100),
+ "invalid configuration (%d) for counter (%d)\n",
+ config, idx);
+
+ /* Reset the cycle count */
+ asm volatile (
+ "SWAP %0, TXTACTCYC\n\t"
+ : "=&r" (tmp)
+ );
+ goto unlock;
+ }
+
+ /* Check for a core internal or performance channel event. */
+ if (tmp) {
+ void *perf_addr = (void *)PERF_COUNT(idx);
+
+ /*
+ * Anything other than a cycle count will write the low-
+ * nibble to the correct counter register.
+ */
+ switch (tmp) {
+ case 0xd0:
+ perf_addr = (void *)PERF_ICORE(idx);
+ break;
+
+ case 0xf0:
+ perf_addr = (void *)PERF_CHAN(idx);
+ break;
+ }
+
+ metag_out32((tmp & 0x0f), perf_addr);
+
+ /*
+ * Now we use the high nibble as the performance event to
+ * to count.
+ */
+ config = tmp >> 4;
+ }
+
+ /*
+ * Enabled counters start from 0. Early cores clear the count on
+ * write but newer cores don't, so we make sure that the count is
+ * set to 0.
+ */
+ tmp = ((config & 0xf) << 28) |
+ ((1 << 24) << cpu_2_hwthread_id[get_cpu()]);
+ metag_out32(tmp, PERF_COUNT(idx));
+unlock:
+ raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
+}
+
+static void metag_pmu_disable_counter(struct hw_perf_event *event, int idx)
+{
+ struct cpu_hw_events *events = &__get_cpu_var(cpu_hw_events);
+ unsigned int tmp = 0;
+ unsigned long flags;
+
+ /*
+ * The cycle counter can't be disabled per se, as it's a hardware
+ * thread register which is always counting. We merely return if this
+ * is the counter we're attempting to disable.
+ */
+ if (METAG_INST_COUNTER == idx)
+ return;
+
+ /*
+ * The counter value _should_ have been read prior to disabling,
+ * as if we're running on an early core then the value gets reset to
+ * 0, and any read after that would be useless. On the newer cores,
+ * however, it's better to read-modify-update this for purposes of
+ * the overflow interrupt.
+ * Here we remove the thread id AND the event nibble (there are at
+ * least two events that count events that are core global and ignore
+ * the thread id mask). This only works because we don't mix thread
+ * performance counts, and event 0x00 requires a thread id mask!
+ */
+ raw_spin_lock_irqsave(&events->pmu_lock, flags);
+
+ tmp = metag_in32(PERF_COUNT(idx));
+ tmp &= 0x00ffffff;
+ metag_out32(tmp, PERF_COUNT(idx));
+
+ raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
+}
+
+static u64 metag_pmu_read_counter(int idx)
+{
+ u32 tmp = 0;
+
+ /* The act of reading the cycle counter also clears it */
+ if (METAG_INST_COUNTER == idx) {
+ asm volatile (
+ "SWAP %0, TXTACTCYC\n\t"
+ : "=r" (tmp)
+ );
+ goto out;
+ }
+
+ tmp = metag_in32(PERF_COUNT(idx)) & 0x00ffffff;
+out:
+ return tmp;
+}
+
+static void metag_pmu_write_counter(int idx, u32 val)
+{
+ struct cpu_hw_events *events = &__get_cpu_var(cpu_hw_events);
+ u32 tmp = 0;
+ unsigned long flags;
+
+ /*
+ * This _shouldn't_ happen, but if it does, then we can just
+ * ignore the write, as the register is read-only and clear-on-write.
+ */
+ if (METAG_INST_COUNTER == idx)
+ return;
+
+ /*
+ * We'll keep the thread mask and event id, and just update the
+ * counter itself. Also , we should bound the value to 24-bits.
+ */
+ raw_spin_lock_irqsave(&events->pmu_lock, flags);
+
+ val &= 0x00ffffff;
+ tmp = metag_in32(PERF_COUNT(idx)) & 0xff000000;
+ val |= tmp;
+ metag_out32(val, PERF_COUNT(idx));
+
+ raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
+}
+
+static int metag_pmu_event_map(int idx)
+{
+ return metag_general_events[idx];
+}
+
+static irqreturn_t metag_pmu_counter_overflow(int irq, void *dev)
+{
+ int idx = (int)dev;
+ struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
+ struct perf_event *event = cpuhw->events[idx];
+ struct hw_perf_event *hwc = &event->hw;
+ struct pt_regs *regs = get_irq_regs();
+ struct perf_sample_data sampledata;
+ unsigned long flags;
+ u32 counter = 0;
+
+ /*
+ * We need to stop the core temporarily from generating another
+ * interrupt while we disable this counter. However, we don't want
+ * to flag the counter as free
+ */
+ __global_lock2(flags);
+ counter = metag_in32(PERF_COUNT(idx));
+ metag_out32((counter & 0x00ffffff), PERF_COUNT(idx));
+ __global_unlock2(flags);
+
+ /* Update the counts and reset the sample period */
+ metag_pmu_event_update(event, hwc, idx);
+ perf_sample_data_init(&sampledata, 0, hwc->last_period);
+ metag_pmu_event_set_period(event, hwc, idx);
+
+ /*
+ * Enable the counter again once core overflow processing has
+ * completed.
+ */
+ if (!perf_event_overflow(event, &sampledata, regs))
+ metag_out32(counter, PERF_COUNT(idx));
+
+ return IRQ_HANDLED;
+}
+
+static struct metag_pmu _metag_pmu = {
+ .handle_irq = metag_pmu_counter_overflow,
+ .enable = metag_pmu_enable_counter,
+ .disable = metag_pmu_disable_counter,
+ .read = metag_pmu_read_counter,
+ .write = metag_pmu_write_counter,
+ .event_map = metag_pmu_event_map,
+ .cache_events = &metag_pmu_cache_events,
+ .max_period = MAX_PERIOD,
+ .max_events = MAX_HWEVENTS,
+};
+
+/* PMU CPU hotplug notifier */
+static int __cpuinit metag_pmu_cpu_notify(struct notifier_block *b,
+ unsigned long action, void *hcpu)
+{
+ unsigned int cpu = (unsigned int)hcpu;
+ struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
+
+ if ((action & ~CPU_TASKS_FROZEN) != CPU_STARTING)
+ return NOTIFY_DONE;
+
+ memset(cpuc, 0, sizeof(struct cpu_hw_events));
+ raw_spin_lock_init(&cpuc->pmu_lock);
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block __cpuinitdata metag_pmu_notifier = {
+ .notifier_call = metag_pmu_cpu_notify,
+};
+
+/* PMU Initialisation */
+static int __init init_hw_perf_events(void)
+{
+ int ret = 0, cpu;
+ u32 version = *(u32 *)METAC_ID;
+ int major = (version & METAC_ID_MAJOR_BITS) >> METAC_ID_MAJOR_S;
+ int min_rev = (version & (METAC_ID_MINOR_BITS | METAC_ID_REV_BITS))
+ >> METAC_ID_REV_S;
+
+ /* Not a Meta 2 core, then not supported */
+ if (0x02 > major) {
+ pr_info("no hardware counter support available\n");
+ goto out;
+ } else if (0x02 == major) {
+ metag_pmu = &_metag_pmu;
+
+ if (min_rev < 0x0104) {
+ /*
+ * A core without overflow interrupts, and clear-on-
+ * write counters.
+ */
+ metag_pmu->handle_irq = NULL;
+ metag_pmu->write = NULL;
+ metag_pmu->max_period = 0;
+ }
+
+ metag_pmu->name = "Meta 2";
+ metag_pmu->version = version;
+ metag_pmu->pmu = pmu;
+ }
+
+ pr_info("enabled with %s PMU driver, %d counters available\n",
+ metag_pmu->name, metag_pmu->max_events);
+
+ /* Initialise the active events and reservation mutex */
+ atomic_set(&metag_pmu->active_events, 0);
+ mutex_init(&metag_pmu->reserve_mutex);
+
+ /* Clear the counters */
+ metag_out32(0, PERF_COUNT(0));
+ metag_out32(0, PERF_COUNT(1));
+
+ for_each_possible_cpu(cpu) {
+ struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
+
+ memset(cpuc, 0, sizeof(struct cpu_hw_events));
+ raw_spin_lock_init(&cpuc->pmu_lock);
+ }
+
+ register_cpu_notifier(&metag_pmu_notifier);
+ ret = perf_pmu_register(&pmu, (char *)metag_pmu->name, PERF_TYPE_RAW);
+out:
+ return ret;
+}
+early_initcall(init_hw_perf_events);
diff --git a/arch/metag/kernel/perf/perf_event.h b/arch/metag/kernel/perf/perf_event.h
new file mode 100644
index 0000000..fd10a13
--- /dev/null
+++ b/arch/metag/kernel/perf/perf_event.h
@@ -0,0 +1,106 @@
+/*
+ * Meta performance counter support.
+ * Copyright (C) 2012 Imagination Technologies Ltd
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#ifndef METAG_PERF_EVENT_H_
+#define METAG_PERF_EVENT_H_
+
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/perf_event.h>
+
+/* For performance counter definitions */
+#include <asm/metag_mem.h>
+
+/*
+ * The Meta core has two performance counters, with 24-bit resolution. Newer
+ * cores generate an overflow interrupt on transition from 0xffffff to 0.
+ *
+ * Each counter consists of the counter id, hardware thread id, and the count
+ * itself; each counter can be assigned to multiple hardware threads at any
+ * one time, with the returned count being an aggregate of events. A small
+ * number of events are thread global, i.e. they count the aggregate of all
+ * threads' events, regardless of the thread selected.
+ *
+ * Newer cores can store an arbitrary 24-bit number in the counter, whereas
+ * older cores will clear the counter bits on write.
+ *
+ * We also have a pseudo-counter in the form of the thread active cycles
+ * counter (which, incidentally, is also bound to
+ */
+
+#define MAX_HWEVENTS 3
+#define MAX_PERIOD ((1UL << 24) - 1)
+#define METAG_INST_COUNTER (MAX_HWEVENTS - 1)
+
+/**
+ * struct cpu_hw_events - a processor core's performance events
+ * @events: an array of perf_events active for a given index.
+ * @used_mask: a bitmap of in-use counters.
+ * @pmu_lock: a perf counter lock
+ *
+ * This is a per-cpu/core structure that maintains a record of its
+ * performance counters' state.
+ */
+struct cpu_hw_events {
+ struct perf_event *events[MAX_HWEVENTS];
+ unsigned long used_mask[BITS_TO_LONGS(MAX_HWEVENTS)];
+ raw_spinlock_t pmu_lock;
+};
+
+/**
+ * struct metag_pmu - the Meta PMU structure
+ * @pmu: core pmu structure
+ * @name: pmu name
+ * @version: core version
+ * @handle_irq: overflow interrupt handler
+ * @enable: enable a counter
+ * @disable: disable a counter
+ * @read: read the value of a counter
+ * @write: write a value to a counter
+ * @event_map: kernel event to counter event id map
+ * @cache_events: kernel cache counter to core cache counter map
+ * @max_period: maximum value of the counter before overflow
+ * @max_events: maximum number of counters available at any one time
+ * @active_events: number of active counters
+ * @reserve_mutex: counter reservation mutex
+ *
+ * This describes the main functionality and data used by the performance
+ * event core.
+ */
+struct metag_pmu {
+ struct pmu pmu;
+ const char *name;
+ u32 version;
+ irqreturn_t (*handle_irq)(int irq_num, void *dev);
+ void (*enable)(struct hw_perf_event *evt, int idx);
+ void (*disable)(struct hw_perf_event *evt, int idx);
+ u64 (*read)(int idx);
+ void (*write)(int idx, u32 val);
+ int (*event_map)(int idx);
+ const int (*cache_events)[PERF_COUNT_HW_CACHE_MAX]
+ [PERF_COUNT_HW_CACHE_OP_MAX]
+ [PERF_COUNT_HW_CACHE_RESULT_MAX];
+ u32 max_period;
+ int max_events;
+ atomic_t active_events;
+ struct mutex reserve_mutex;
+};
+
+/* Convenience macros for accessing the perf counters */
+/* Define some convenience accessors */
+#define PERF_COUNT(x) (PERF_COUNT0 + (sizeof(u64) * (x)))
+#define PERF_ICORE(x) (PERF_ICORE0 + (sizeof(u64) * (x)))
+#define PERF_CHAN(x) (PERF_CHAN0 + (sizeof(u64) * (x)))
+
+/* Cache index macros */
+#define C(x) PERF_COUNT_HW_CACHE_##x
+#define CACHE_OP_UNSUPPORTED 0xfffe
+#define CACHE_OP_NONSENSE 0xffff
+
+#endif
diff --git a/arch/metag/kernel/perf_callchain.c b/arch/metag/kernel/perf_callchain.c
new file mode 100644
index 0000000..3156334
--- /dev/null
+++ b/arch/metag/kernel/perf_callchain.c
@@ -0,0 +1,96 @@
+/*
+ * Perf callchain handling code.
+ *
+ * Based on the ARM perf implementation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/perf_event.h>
+#include <linux/uaccess.h>
+#include <asm/ptrace.h>
+#include <asm/stacktrace.h>
+
+static bool is_valid_call(unsigned long calladdr)
+{
+ unsigned int callinsn;
+
+ /* Check the possible return address is aligned. */
+ if (!(calladdr & 0x3)) {
+ if (!get_user(callinsn, (unsigned int *)calladdr)) {
+ /* Check for CALLR or SWAP PC,D1RtP. */
+ if ((callinsn & 0xff000000) == 0xab000000 ||
+ callinsn == 0xa3200aa0)
+ return true;
+ }
+ }
+ return false;
+}
+
+static struct metag_frame __user *
+user_backtrace(struct metag_frame __user *user_frame,
+ struct perf_callchain_entry *entry)
+{
+ struct metag_frame frame;
+ unsigned long calladdr;
+
+ /* We cannot rely on having frame pointers in user code. */
+ while (1) {
+ /* Also check accessibility of one struct frame beyond */
+ if (!access_ok(VERIFY_READ, user_frame, sizeof(frame)))
+ return 0;
+ if (__copy_from_user_inatomic(&frame, user_frame,
+ sizeof(frame)))
+ return 0;
+
+ --user_frame;
+
+ calladdr = frame.lr - 4;
+ if (is_valid_call(calladdr)) {
+ perf_callchain_store(entry, calladdr);
+ return user_frame;
+ }
+ }
+
+ return 0;
+}
+
+void
+perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
+{
+ unsigned long sp = regs->ctx.AX[0].U0;
+ struct metag_frame __user *frame;
+
+ frame = (struct metag_frame __user *)sp;
+
+ --frame;
+
+ while ((entry->nr < PERF_MAX_STACK_DEPTH) && frame)
+ frame = user_backtrace(frame, entry);
+}
+
+/*
+ * Gets called by walk_stackframe() for every stackframe. This will be called
+ * whist unwinding the stackframe and is like a subroutine return so we use
+ * the PC.
+ */
+static int
+callchain_trace(struct stackframe *fr,
+ void *data)
+{
+ struct perf_callchain_entry *entry = data;
+ perf_callchain_store(entry, fr->pc);
+ return 0;
+}
+
+void
+perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs)
+{
+ struct stackframe fr;
+
+ fr.fp = regs->ctx.AX[1].U0;
+ fr.sp = regs->ctx.AX[0].U0;
+ fr.lr = regs->ctx.DX[4].U1;
+ fr.pc = regs->ctx.CurrPC;
+ walk_stackframe(&fr, callchain_trace, entry);
+}
--
1.7.7.6



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