Blackfin: initial perf_event support

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

2 files changed, 499 insertions, 0 deletions

diff --git a/arch/blackfin/kernel/Makefile b/arch/blackfin/kernel/Makefile
index 18ba6abd66d..d550b24d9e9 100644
--- a/arch/blackfin/kernel/Makefile
+++ b/arch/blackfin/kernel/Makefile
@@ -33,6 +33,7 @@ obj-$(CONFIG_EARLY_PRINTK)           += shadow_console.o
 obj-$(CONFIG_STACKTRACE)             += stacktrace.o
 obj-$(CONFIG_DEBUG_VERBOSE)          += trace.o
 obj-$(CONFIG_BFIN_PSEUDODBG_INSNS)   += pseudodbg.o
+obj-$(CONFIG_PERF_EVENTS)            += perf_event.o
 
 # the kgdb test puts code into L2 and without linker
 # relaxation, we need to force long calls to/from it
diff --git a/arch/blackfin/kernel/perf_event.c b/arch/blackfin/kernel/perf_event.c
new file mode 100644
index 00000000000..04300f29c0e
--- /dev/null
+++ b/arch/blackfin/kernel/perf_event.c
@@ -0,0 +1,498 @@
+/*
+ * Blackfin performance counters
+ *
+ * Copyright 2011 Analog Devices Inc.
+ *
+ * Ripped from SuperH version:
+ *
+ *  Copyright (C) 2009  Paul Mundt
+ *
+ * Heavily based on the x86 and PowerPC implementations.
+ *
+ * x86:
+ *  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>
+ *  Copyright (C) 2009 Intel Corporation, <markus.t.metzger@intel.com>
+ *
+ * ppc:
+ *  Copyright 2008-2009 Paul Mackerras, IBM Corporation.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/perf_event.h>
+#include <asm/bfin_pfmon.h>
+
+/*
+ * We have two counters, and each counter can support an event type.
+ * The 'o' is PFCNTx=1 and 's' is PFCNTx=0
+ *
+ * 0x04 o pc invariant branches
+ * 0x06 o mispredicted branches
+ * 0x09 o predicted branches taken
+ * 0x0B o EXCPT insn
+ * 0x0C o CSYNC/SSYNC insn
+ * 0x0D o Insns committed
+ * 0x0E o Interrupts taken
+ * 0x0F o Misaligned address exceptions
+ * 0x80 o Code memory fetches stalled due to DMA
+ * 0x83 o 64bit insn fetches delivered
+ * 0x9A o data cache fills (bank a)
+ * 0x9B o data cache fills (bank b)
+ * 0x9C o data cache lines evicted (bank a)
+ * 0x9D o data cache lines evicted (bank b)
+ * 0x9E o data cache high priority fills
+ * 0x9F o data cache low priority fills
+ * 0x00 s loop 0 iterations
+ * 0x01 s loop 1 iterations
+ * 0x0A s CSYNC/SSYNC stalls
+ * 0x10 s DAG read/after write hazards
+ * 0x13 s RAW data hazards
+ * 0x81 s code TAG stalls
+ * 0x82 s code fill stalls
+ * 0x90 s processor to memory stalls
+ * 0x91 s data memory stalls not hidden by 0x90
+ * 0x92 s data store buffer full stalls
+ * 0x93 s data memory write buffer full stalls due to high->low priority
+ * 0x95 s data memory fill buffer stalls
+ * 0x96 s data TAG collision stalls
+ * 0x97 s data collision stalls
+ * 0x98 s data stalls
+ * 0x99 s data stalls sent to processor
+ */
+
+static const int event_map[] = {
+	/* use CYCLES cpu register */
+	[PERF_COUNT_HW_CPU_CYCLES]          = -1,
+	[PERF_COUNT_HW_INSTRUCTIONS]        = 0x0D,
+	[PERF_COUNT_HW_CACHE_REFERENCES]    = -1,
+	[PERF_COUNT_HW_CACHE_MISSES]        = 0x83,
+	[PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = 0x09,
+	[PERF_COUNT_HW_BRANCH_MISSES]       = 0x06,
+	[PERF_COUNT_HW_BUS_CYCLES]          = -1,
+};
+
+#define C(x)	PERF_COUNT_HW_CACHE_##x
+
+static const int cache_events[PERF_COUNT_HW_CACHE_MAX]
+                             [PERF_COUNT_HW_CACHE_OP_MAX]
+                             [PERF_COUNT_HW_CACHE_RESULT_MAX] =
+{
+	[C(L1D)] = {	/* Data bank A */
+		[C(OP_READ)] = {
+			[C(RESULT_ACCESS)] = 0,
+			[C(RESULT_MISS)  ] = 0x9A,
+		},
+		[C(OP_WRITE)] = {
+			[C(RESULT_ACCESS)] = 0,
+			[C(RESULT_MISS)  ] = 0,
+		},
+		[C(OP_PREFETCH)] = {
+			[C(RESULT_ACCESS)] = 0,
+			[C(RESULT_MISS)  ] = 0,
+		},
+	},
+
+	[C(L1I)] = {
+		[C(OP_READ)] = {
+			[C(RESULT_ACCESS)] = 0,
+			[C(RESULT_MISS)  ] = 0x83,
+		},
+		[C(OP_WRITE)] = {
+			[C(RESULT_ACCESS)] = -1,
+			[C(RESULT_MISS)  ] = -1,
+		},
+		[C(OP_PREFETCH)] = {
+			[C(RESULT_ACCESS)] = 0,
+			[C(RESULT_MISS)  ] = 0,
+		},
+	},
+
+	[C(LL)] = {
+		[C(OP_READ)] = {
+			[C(RESULT_ACCESS)] = -1,
+			[C(RESULT_MISS)  ] = -1,
+		},
+		[C(OP_WRITE)] = {
+			[C(RESULT_ACCESS)] = -1,
+			[C(RESULT_MISS)  ] = -1,
+		},
+		[C(OP_PREFETCH)] = {
+			[C(RESULT_ACCESS)] = -1,
+			[C(RESULT_MISS)  ] = -1,
+		},
+	},
+
+	[C(DTLB)] = {
+		[C(OP_READ)] = {
+			[C(RESULT_ACCESS)] = -1,
+			[C(RESULT_MISS)  ] = -1,
+		},
+		[C(OP_WRITE)] = {
+			[C(RESULT_ACCESS)] = -1,
+			[C(RESULT_MISS)  ] = -1,
+		},
+		[C(OP_PREFETCH)] = {
+			[C(RESULT_ACCESS)] = -1,
+			[C(RESULT_MISS)  ] = -1,
+		},
+	},
+
+	[C(ITLB)] = {
+		[C(OP_READ)] = {
+			[C(RESULT_ACCESS)] = -1,
+			[C(RESULT_MISS)  ] = -1,
+		},
+		[C(OP_WRITE)] = {
+			[C(RESULT_ACCESS)] = -1,
+			[C(RESULT_MISS)  ] = -1,
+		},
+		[C(OP_PREFETCH)] = {
+			[C(RESULT_ACCESS)] = -1,
+			[C(RESULT_MISS)  ] = -1,
+		},
+	},
+
+	[C(BPU)] = {
+		[C(OP_READ)] = {
+			[C(RESULT_ACCESS)] = -1,
+			[C(RESULT_MISS)  ] = -1,
+		},
+		[C(OP_WRITE)] = {
+			[C(RESULT_ACCESS)] = -1,
+			[C(RESULT_MISS)  ] = -1,
+		},
+		[C(OP_PREFETCH)] = {
+			[C(RESULT_ACCESS)] = -1,
+			[C(RESULT_MISS)  ] = -1,
+		},
+	},
+};
+
+const char *perf_pmu_name(void)
+{
+	return "bfin";
+}
+EXPORT_SYMBOL(perf_pmu_name);
+
+int perf_num_counters(void)
+{
+	return ARRAY_SIZE(event_map);
+}
+EXPORT_SYMBOL(perf_num_counters);
+
+static u64 bfin_pfmon_read(int idx)
+{
+	return bfin_read32(PFCNTR0 + (idx * 4));
+}
+
+static void bfin_pfmon_disable(struct hw_perf_event *hwc, int idx)
+{
+	bfin_write_PFCTL(bfin_read_PFCTL() & ~PFCEN(idx, PFCEN_MASK));
+}
+
+static void bfin_pfmon_enable(struct hw_perf_event *hwc, int idx)
+{
+	u32 val, mask;
+
+	val = PFPWR;
+	if (idx) {
+		mask = ~(PFCNT1 | PFMON1 | PFCEN1 | PEMUSW1);
+		/* The packed config is for event0, so shift it to event1 slots */
+		val |= (hwc->config << (PFMON1_P - PFMON0_P));
+		val |= (hwc->config & PFCNT0) << (PFCNT1_P - PFCNT0_P);
+		bfin_write_PFCNTR1(0);
+	} else {
+		mask = ~(PFCNT0 | PFMON0 | PFCEN0 | PEMUSW0);
+		val |= hwc->config;
+		bfin_write_PFCNTR0(0);
+	}
+
+	bfin_write_PFCTL((bfin_read_PFCTL() & mask) | val);
+}
+
+static void bfin_pfmon_disable_all(void)
+{
+	bfin_write_PFCTL(bfin_read_PFCTL() & ~PFPWR);
+}
+
+static void bfin_pfmon_enable_all(void)
+{
+	bfin_write_PFCTL(bfin_read_PFCTL() | PFPWR);
+}
+
+struct cpu_hw_events {
+	struct perf_event *events[MAX_HWEVENTS];
+	unsigned long used_mask[BITS_TO_LONGS(MAX_HWEVENTS)];
+};
+DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events);
+
+static int hw_perf_cache_event(int config, int *evp)
+{
+	unsigned long type, op, result;
+	int ev;
+
+	/* 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 = cache_events[type][op][result];
+	if (ev == 0)
+		return -EOPNOTSUPP;
+	if (ev == -1)
+		return -EINVAL;
+	*evp = ev;
+	return 0;
+}
+
+static void bfin_perf_event_update(struct perf_event *event,
+				   struct hw_perf_event *hwc, int idx)
+{
+	u64 prev_raw_count, new_raw_count;
+	s64 delta;
+	int shift = 0;
+
+	/*
+	 * Depending on the counter configuration, they may or may not
+	 * be chained, in which case the previous counter value can be
+	 * updated underneath us if the lower-half overflows.
+	 *
+	 * Our tactic to handle this is to first atomically read and
+	 * exchange a new raw count - then add that new-prev delta
+	 * count to the generic counter atomically.
+	 *
+	 * As there is no interrupt associated with the overflow events,
+	 * this is the simplest approach for maintaining consistency.
+	 */
+again:
+	prev_raw_count = local64_read(&hwc->prev_count);
+	new_raw_count = bfin_pfmon_read(idx);
+
+	if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
+			     new_raw_count) != prev_raw_count)
+		goto again;
+
+	/*
+	 * Now we have the new raw value and have updated the prev
+	 * timestamp already. We can now calculate the elapsed delta
+	 * (counter-)time and add that to the generic counter.
+	 *
+	 * Careful, not all hw sign-extends above the physical width
+	 * of the count.
+	 */
+	delta = (new_raw_count << shift) - (prev_raw_count << shift);
+	delta >>= shift;
+
+	local64_add(delta, &event->count);
+}
+
+static void bfin_pmu_stop(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 (!(event->hw.state & PERF_HES_STOPPED)) {
+		bfin_pfmon_disable(hwc, idx);
+		cpuc->events[idx] = NULL;
+		event->hw.state |= PERF_HES_STOPPED;
+	}
+
+	if ((flags & PERF_EF_UPDATE) && !(event->hw.state & PERF_HES_UPTODATE)) {
+		bfin_perf_event_update(event, &event->hw, idx);
+		event->hw.state |= PERF_HES_UPTODATE;
+	}
+}
+
+static void bfin_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;
+
+	if (flags & PERF_EF_RELOAD)
+		WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
+
+	cpuc->events[idx] = event;
+	event->hw.state = 0;
+	bfin_pfmon_enable(hwc, idx);
+}
+
+static void bfin_pmu_del(struct perf_event *event, int flags)
+{
+	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+
+	bfin_pmu_stop(event, PERF_EF_UPDATE);
+	__clear_bit(event->hw.idx, cpuc->used_mask);
+
+	perf_event_update_userpage(event);
+}
+
+static int bfin_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 = hwc->idx;
+	int ret = -EAGAIN;
+
+	perf_pmu_disable(event->pmu);
+
+	if (__test_and_set_bit(idx, cpuc->used_mask)) {
+		idx = find_first_zero_bit(cpuc->used_mask, MAX_HWEVENTS);
+		if (idx == MAX_HWEVENTS)
+			goto out;
+
+		__set_bit(idx, cpuc->used_mask);
+		hwc->idx = idx;
+	}
+
+	bfin_pfmon_disable(hwc, idx);
+
+	event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
+	if (flags & PERF_EF_START)
+		bfin_pmu_start(event, PERF_EF_RELOAD);
+
+	perf_event_update_userpage(event);
+	ret = 0;
+out:
+	perf_pmu_enable(event->pmu);
+	return ret;
+}
+
+static void bfin_pmu_read(struct perf_event *event)
+{
+	bfin_perf_event_update(event, &event->hw, event->hw.idx);
+}
+
+static int bfin_pmu_event_init(struct perf_event *event)
+{
+	struct perf_event_attr *attr = &event->attr;
+	struct hw_perf_event *hwc = &event->hw;
+	int config = -1;
+	int ret;
+
+	if (attr->exclude_hv || attr->exclude_idle)
+		return -EPERM;
+
+	/*
+	 * All of the on-chip counters are "limited", in that they have
+	 * no interrupts, and are therefore unable to do sampling without
+	 * further work and timer assistance.
+	 */
+	if (hwc->sample_period)
+		return -EINVAL;
+
+	ret = 0;
+	switch (attr->type) {
+	case PERF_TYPE_RAW:
+		config = PFMON(0, attr->config & PFMON_MASK) |
+			PFCNT(0, !(attr->config & 0x100));
+		break;
+	case PERF_TYPE_HW_CACHE:
+		ret = hw_perf_cache_event(attr->config, &config);
+		break;
+	case PERF_TYPE_HARDWARE:
+		if (attr->config >= ARRAY_SIZE(event_map))
+			return -EINVAL;
+
+		config = event_map[attr->config];
+		break;
+	}
+
+	if (config == -1)
+		return -EINVAL;
+
+	if (!attr->exclude_kernel)
+		config |= PFCEN(0, PFCEN_ENABLE_SUPV);
+	if (!attr->exclude_user)
+		config |= PFCEN(0, PFCEN_ENABLE_USER);
+
+	hwc->config |= config;
+
+	return ret;
+}
+
+static void bfin_pmu_enable(struct pmu *pmu)
+{
+	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+	struct perf_event *event;
+	struct hw_perf_event *hwc;
+	int i;
+
+	for (i = 0; i < MAX_HWEVENTS; ++i) {
+		event = cpuc->events[i];
+		if (!event)
+			continue;
+		hwc = &event->hw;
+		bfin_pfmon_enable(hwc, hwc->idx);
+	}
+
+	bfin_pfmon_enable_all();
+}
+
+static void bfin_pmu_disable(struct pmu *pmu)
+{
+	bfin_pfmon_disable_all();
+}
+
+static struct pmu pmu = {
+	.pmu_enable  = bfin_pmu_enable,
+	.pmu_disable = bfin_pmu_disable,
+	.event_init  = bfin_pmu_event_init,
+	.add         = bfin_pmu_add,
+	.del         = bfin_pmu_del,
+	.start       = bfin_pmu_start,
+	.stop        = bfin_pmu_stop,
+	.read        = bfin_pmu_read,
+};
+
+static void bfin_pmu_setup(int cpu)
+{
+	struct cpu_hw_events *cpuhw = &per_cpu(cpu_hw_events, cpu);
+
+	memset(cpuhw, 0, sizeof(struct cpu_hw_events));
+}
+
+static int __cpuinit
+bfin_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu)
+{
+	unsigned int cpu = (long)hcpu;
+
+	switch (action & ~CPU_TASKS_FROZEN) {
+	case CPU_UP_PREPARE:
+		bfin_write_PFCTL(0);
+		bfin_pmu_setup(cpu);
+		break;
+
+	default:
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static int __init bfin_pmu_init(void)
+{
+	int ret;
+
+	ret = perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
+	if (!ret)
+		perf_cpu_notifier(bfin_pmu_notifier);
+
+	return ret;
+}
+early_initcall(bfin_pmu_init);