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|
/*
* Performance events x86 architecture code
*
* 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>
* Copyright (C) 2009 Google, Inc., Stephane Eranian
*
* For licencing details see kernel-base/COPYING
*/
#include <linux/perf_event.h>
#include <linux/capability.h>
#include <linux/notifier.h>
#include <linux/hardirq.h>
#include <linux/kprobes.h>
#include <linux/module.h>
#include <linux/kdebug.h>
#include <linux/sched.h>
#include <linux/uaccess.h>
#include <linux/highmem.h>
#include <linux/cpu.h>
#include <linux/bitops.h>
#include <asm/apic.h>
#include <asm/stacktrace.h>
#include <asm/nmi.h>
static u64 perf_event_mask __read_mostly;
/* The maximal number of PEBS events: */
#define MAX_PEBS_EVENTS 4
/* The size of a BTS record in bytes: */
#define BTS_RECORD_SIZE 24
/* The size of a per-cpu BTS buffer in bytes: */
#define BTS_BUFFER_SIZE (BTS_RECORD_SIZE * 2048)
/* The BTS overflow threshold in bytes from the end of the buffer: */
#define BTS_OVFL_TH (BTS_RECORD_SIZE * 128)
/*
* Bits in the debugctlmsr controlling branch tracing.
*/
#define X86_DEBUGCTL_TR (1 << 6)
#define X86_DEBUGCTL_BTS (1 << 7)
#define X86_DEBUGCTL_BTINT (1 << 8)
#define X86_DEBUGCTL_BTS_OFF_OS (1 << 9)
#define X86_DEBUGCTL_BTS_OFF_USR (1 << 10)
/*
* A debug store configuration.
*
* We only support architectures that use 64bit fields.
*/
struct debug_store {
u64 bts_buffer_base;
u64 bts_index;
u64 bts_absolute_maximum;
u64 bts_interrupt_threshold;
u64 pebs_buffer_base;
u64 pebs_index;
u64 pebs_absolute_maximum;
u64 pebs_interrupt_threshold;
u64 pebs_event_reset[MAX_PEBS_EVENTS];
};
struct event_constraint {
union {
unsigned long idxmsk[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
u64 idxmsk64;
};
u64 code;
u64 cmask;
int weight;
};
struct amd_nb {
int nb_id; /* NorthBridge id */
int refcnt; /* reference count */
struct perf_event *owners[X86_PMC_IDX_MAX];
struct event_constraint event_constraints[X86_PMC_IDX_MAX];
};
struct cpu_hw_events {
struct perf_event *events[X86_PMC_IDX_MAX]; /* in counter order */
unsigned long active_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
unsigned long interrupts;
int enabled;
struct debug_store *ds;
int n_events;
int n_added;
int assign[X86_PMC_IDX_MAX]; /* event to counter assignment */
u64 tags[X86_PMC_IDX_MAX];
struct perf_event *event_list[X86_PMC_IDX_MAX]; /* in enabled order */
struct amd_nb *amd_nb;
};
#define __EVENT_CONSTRAINT(c, n, m, w) {\
{ .idxmsk64 = (n) }, \
.code = (c), \
.cmask = (m), \
.weight = (w), \
}
#define EVENT_CONSTRAINT(c, n, m) \
__EVENT_CONSTRAINT(c, n, m, HWEIGHT(n))
#define INTEL_EVENT_CONSTRAINT(c, n) \
EVENT_CONSTRAINT(c, n, INTEL_ARCH_EVTSEL_MASK)
#define FIXED_EVENT_CONSTRAINT(c, n) \
EVENT_CONSTRAINT(c, (1ULL << (32+n)), INTEL_ARCH_FIXED_MASK)
#define EVENT_CONSTRAINT_END \
EVENT_CONSTRAINT(0, 0, 0)
#define for_each_event_constraint(e, c) \
for ((e) = (c); (e)->cmask; (e)++)
/*
* struct x86_pmu - generic x86 pmu
*/
struct x86_pmu {
const char *name;
int version;
int (*handle_irq)(struct pt_regs *);
void (*disable_all)(void);
void (*enable_all)(void);
void (*enable)(struct perf_event *);
void (*disable)(struct perf_event *);
unsigned eventsel;
unsigned perfctr;
u64 (*event_map)(int);
u64 (*raw_event)(u64);
int max_events;
int num_events;
int num_events_fixed;
int event_bits;
u64 event_mask;
int apic;
u64 max_period;
u64 intel_ctrl;
void (*enable_bts)(u64 config);
void (*disable_bts)(void);
struct event_constraint *
(*get_event_constraints)(struct cpu_hw_events *cpuc,
struct perf_event *event);
void (*put_event_constraints)(struct cpu_hw_events *cpuc,
struct perf_event *event);
struct event_constraint *event_constraints;
void (*cpu_prepare)(int cpu);
void (*cpu_starting)(int cpu);
void (*cpu_dying)(int cpu);
void (*cpu_dead)(int cpu);
};
static struct x86_pmu x86_pmu __read_mostly;
static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = {
.enabled = 1,
};
static int x86_perf_event_set_period(struct perf_event *event);
/*
* Generalized hw caching related hw_event table, filled
* in on a per model basis. A value of 0 means
* 'not supported', -1 means 'hw_event makes no sense on
* this CPU', any other value means the raw hw_event
* ID.
*/
#define C(x) PERF_COUNT_HW_CACHE_##x
static u64 __read_mostly hw_cache_event_ids
[PERF_COUNT_HW_CACHE_MAX]
[PERF_COUNT_HW_CACHE_OP_MAX]
[PERF_COUNT_HW_CACHE_RESULT_MAX];
/*
* Propagate event elapsed time into the generic event.
* Can only be executed on the CPU where the event is active.
* Returns the delta events processed.
*/
static u64
x86_perf_event_update(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
int shift = 64 - x86_pmu.event_bits;
u64 prev_raw_count, new_raw_count;
int idx = hwc->idx;
s64 delta;
if (idx == X86_PMC_IDX_FIXED_BTS)
return 0;
/*
* Careful: an NMI might modify the previous event value.
*
* 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 event atomically:
*/
again:
prev_raw_count = atomic64_read(&hwc->prev_count);
rdmsrl(hwc->event_base + idx, new_raw_count);
if (atomic64_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
* (event-)time and add that to the generic event.
*
* Careful, not all hw sign-extends above the physical width
* of the count.
*/
delta = (new_raw_count << shift) - (prev_raw_count << shift);
delta >>= shift;
atomic64_add(delta, &event->count);
atomic64_sub(delta, &hwc->period_left);
return new_raw_count;
}
static atomic_t active_events;
static DEFINE_MUTEX(pmc_reserve_mutex);
static bool reserve_pmc_hardware(void)
{
#ifdef CONFIG_X86_LOCAL_APIC
int i;
if (nmi_watchdog == NMI_LOCAL_APIC)
disable_lapic_nmi_watchdog();
for (i = 0; i < x86_pmu.num_events; i++) {
if (!reserve_perfctr_nmi(x86_pmu.perfctr + i))
goto perfctr_fail;
}
for (i = 0; i < x86_pmu.num_events; i++) {
if (!reserve_evntsel_nmi(x86_pmu.eventsel + i))
goto eventsel_fail;
}
#endif
return true;
#ifdef CONFIG_X86_LOCAL_APIC
eventsel_fail:
for (i--; i >= 0; i--)
release_evntsel_nmi(x86_pmu.eventsel + i);
i = x86_pmu.num_events;
perfctr_fail:
for (i--; i >= 0; i--)
release_perfctr_nmi(x86_pmu.perfctr + i);
if (nmi_watchdog == NMI_LOCAL_APIC)
enable_lapic_nmi_watchdog();
return false;
#endif
}
static void release_pmc_hardware(void)
{
#ifdef CONFIG_X86_LOCAL_APIC
int i;
for (i = 0; i < x86_pmu.num_events; i++) {
release_perfctr_nmi(x86_pmu.perfctr + i);
release_evntsel_nmi(x86_pmu.eventsel + i);
}
if (nmi_watchdog == NMI_LOCAL_APIC)
enable_lapic_nmi_watchdog();
#endif
}
static inline bool bts_available(void)
{
return x86_pmu.enable_bts != NULL;
}
static void init_debug_store_on_cpu(int cpu)
{
struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
if (!ds)
return;
wrmsr_on_cpu(cpu, MSR_IA32_DS_AREA,
(u32)((u64)(unsigned long)ds),
(u32)((u64)(unsigned long)ds >> 32));
}
static void fini_debug_store_on_cpu(int cpu)
{
if (!per_cpu(cpu_hw_events, cpu).ds)
return;
wrmsr_on_cpu(cpu, MSR_IA32_DS_AREA, 0, 0);
}
static void release_bts_hardware(void)
{
int cpu;
if (!bts_available())
return;
get_online_cpus();
for_each_online_cpu(cpu)
fini_debug_store_on_cpu(cpu);
for_each_possible_cpu(cpu) {
struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
if (!ds)
continue;
per_cpu(cpu_hw_events, cpu).ds = NULL;
kfree((void *)(unsigned long)ds->bts_buffer_base);
kfree(ds);
}
put_online_cpus();
}
static int reserve_bts_hardware(void)
{
int cpu, err = 0;
if (!bts_available())
return 0;
get_online_cpus();
for_each_possible_cpu(cpu) {
struct debug_store *ds;
void *buffer;
err = -ENOMEM;
buffer = kzalloc(BTS_BUFFER_SIZE, GFP_KERNEL);
if (unlikely(!buffer))
break;
ds = kzalloc(sizeof(*ds), GFP_KERNEL);
if (unlikely(!ds)) {
kfree(buffer);
break;
}
ds->bts_buffer_base = (u64)(unsigned long)buffer;
ds->bts_index = ds->bts_buffer_base;
ds->bts_absolute_maximum =
ds->bts_buffer_base + BTS_BUFFER_SIZE;
ds->bts_interrupt_threshold =
ds->bts_absolute_maximum - BTS_OVFL_TH;
per_cpu(cpu_hw_events, cpu).ds = ds;
err = 0;
}
if (err)
release_bts_hardware();
else {
for_each_online_cpu(cpu)
init_debug_store_on_cpu(cpu);
}
put_online_cpus();
return err;
}
static void hw_perf_event_destroy(struct perf_event *event)
{
if (atomic_dec_and_mutex_lock(&active_events, &pmc_reserve_mutex)) {
release_pmc_hardware();
release_bts_hardware();
mutex_unlock(&pmc_reserve_mutex);
}
}
static inline int x86_pmu_initialized(void)
{
return x86_pmu.handle_irq != NULL;
}
static inline int
set_ext_hw_attr(struct hw_perf_event *hwc, struct perf_event_attr *attr)
{
unsigned int cache_type, cache_op, cache_result;
u64 config, val;
config = attr->config;
cache_type = (config >> 0) & 0xff;
if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
return -EINVAL;
cache_op = (config >> 8) & 0xff;
if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
return -EINVAL;
cache_result = (config >> 16) & 0xff;
if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
return -EINVAL;
val = hw_cache_event_ids[cache_type][cache_op][cache_result];
if (val == 0)
return -ENOENT;
if (val == -1)
return -EINVAL;
hwc->config |= val;
return 0;
}
/*
* Setup the hardware configuration for a given attr_type
*/
static int __hw_perf_event_init(struct perf_event *event)
{
struct perf_event_attr *attr = &event->attr;
struct hw_perf_event *hwc = &event->hw;
u64 config;
int err;
if (!x86_pmu_initialized())
return -ENODEV;
err = 0;
if (!atomic_inc_not_zero(&active_events)) {
mutex_lock(&pmc_reserve_mutex);
if (atomic_read(&active_events) == 0) {
if (!reserve_pmc_hardware())
err = -EBUSY;
else
err = reserve_bts_hardware();
}
if (!err)
atomic_inc(&active_events);
mutex_unlock(&pmc_reserve_mutex);
}
if (err)
return err;
event->destroy = hw_perf_event_destroy;
/*
* Generate PMC IRQs:
* (keep 'enabled' bit clear for now)
*/
hwc->config = ARCH_PERFMON_EVENTSEL_INT;
hwc->idx = -1;
hwc->last_cpu = -1;
hwc->last_tag = ~0ULL;
/*
* Count user and OS events unless requested not to.
*/
if (!attr->exclude_user)
hwc->config |= ARCH_PERFMON_EVENTSEL_USR;
if (!attr->exclude_kernel)
hwc->config |= ARCH_PERFMON_EVENTSEL_OS;
if (!hwc->sample_period) {
hwc->sample_period = x86_pmu.max_period;
hwc->last_period = hwc->sample_period;
atomic64_set(&hwc->period_left, hwc->sample_period);
} else {
/*
* If we have a PMU initialized but no APIC
* interrupts, we cannot sample hardware
* events (user-space has to fall back and
* sample via a hrtimer based software event):
*/
if (!x86_pmu.apic)
return -EOPNOTSUPP;
}
/*
* Raw hw_event type provide the config in the hw_event structure
*/
if (attr->type == PERF_TYPE_RAW) {
hwc->config |= x86_pmu.raw_event(attr->config);
if ((hwc->config & ARCH_PERFMON_EVENTSEL_ANY) &&
perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
return -EACCES;
return 0;
}
if (attr->type == PERF_TYPE_HW_CACHE)
return set_ext_hw_attr(hwc, attr);
if (attr->config >= x86_pmu.max_events)
return -EINVAL;
/*
* The generic map:
*/
config = x86_pmu.event_map(attr->config);
if (config == 0)
return -ENOENT;
if (config == -1LL)
return -EINVAL;
/*
* Branch tracing:
*/
if ((attr->config == PERF_COUNT_HW_BRANCH_INSTRUCTIONS) &&
(hwc->sample_period == 1)) {
/* BTS is not supported by this architecture. */
if (!bts_available())
return -EOPNOTSUPP;
/* BTS is currently only allowed for user-mode. */
if (hwc->config & ARCH_PERFMON_EVENTSEL_OS)
return -EOPNOTSUPP;
}
hwc->config |= config;
return 0;
}
static void x86_pmu_disable_all(void)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
int idx;
for (idx = 0; idx < x86_pmu.num_events; idx++) {
u64 val;
if (!test_bit(idx, cpuc->active_mask))
continue;
rdmsrl(x86_pmu.eventsel + idx, val);
if (!(val & ARCH_PERFMON_EVENTSEL_ENABLE))
continue;
val &= ~ARCH_PERFMON_EVENTSEL_ENABLE;
wrmsrl(x86_pmu.eventsel + idx, val);
}
}
void hw_perf_disable(void)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
if (!x86_pmu_initialized())
return;
if (!cpuc->enabled)
return;
cpuc->n_added = 0;
cpuc->enabled = 0;
barrier();
x86_pmu.disable_all();
}
static void x86_pmu_enable_all(void)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
int idx;
for (idx = 0; idx < x86_pmu.num_events; idx++) {
struct perf_event *event = cpuc->events[idx];
u64 val;
if (!test_bit(idx, cpuc->active_mask))
continue;
val = event->hw.config;
val |= ARCH_PERFMON_EVENTSEL_ENABLE;
wrmsrl(x86_pmu.eventsel + idx, val);
}
}
static const struct pmu pmu;
static inline int is_x86_event(struct perf_event *event)
{
return event->pmu == &pmu;
}
static int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign)
{
struct event_constraint *c, *constraints[X86_PMC_IDX_MAX];
unsigned long used_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
int i, j, w, wmax, num = 0;
struct hw_perf_event *hwc;
bitmap_zero(used_mask, X86_PMC_IDX_MAX);
for (i = 0; i < n; i++) {
c = x86_pmu.get_event_constraints(cpuc, cpuc->event_list[i]);
constraints[i] = c;
}
/*
* fastpath, try to reuse previous register
*/
for (i = 0; i < n; i++) {
hwc = &cpuc->event_list[i]->hw;
c = constraints[i];
/* never assigned */
if (hwc->idx == -1)
break;
/* constraint still honored */
if (!test_bit(hwc->idx, c->idxmsk))
break;
/* not already used */
if (test_bit(hwc->idx, used_mask))
break;
__set_bit(hwc->idx, used_mask);
if (assign)
assign[i] = hwc->idx;
}
if (i == n)
goto done;
/*
* begin slow path
*/
bitmap_zero(used_mask, X86_PMC_IDX_MAX);
/*
* weight = number of possible counters
*
* 1 = most constrained, only works on one counter
* wmax = least constrained, works on any counter
*
* assign events to counters starting with most
* constrained events.
*/
wmax = x86_pmu.num_events;
/*
* when fixed event counters are present,
* wmax is incremented by 1 to account
* for one more choice
*/
if (x86_pmu.num_events_fixed)
wmax++;
for (w = 1, num = n; num && w <= wmax; w++) {
/* for each event */
for (i = 0; num && i < n; i++) {
c = constraints[i];
hwc = &cpuc->event_list[i]->hw;
if (c->weight != w)
continue;
for_each_set_bit(j, c->idxmsk, X86_PMC_IDX_MAX) {
if (!test_bit(j, used_mask))
break;
}
if (j == X86_PMC_IDX_MAX)
break;
__set_bit(j, used_mask);
if (assign)
assign[i] = j;
num--;
}
}
done:
/*
* scheduling failed or is just a simulation,
* free resources if necessary
*/
if (!assign || num) {
for (i = 0; i < n; i++) {
if (x86_pmu.put_event_constraints)
x86_pmu.put_event_constraints(cpuc, cpuc->event_list[i]);
}
}
return num ? -ENOSPC : 0;
}
/*
* dogrp: true if must collect siblings events (group)
* returns total number of events and error code
*/
static int collect_events(struct cpu_hw_events *cpuc, struct perf_event *leader, bool dogrp)
{
struct perf_event *event;
int n, max_count;
max_count = x86_pmu.num_events + x86_pmu.num_events_fixed;
/* current number of events already accepted */
n = cpuc->n_events;
if (is_x86_event(leader)) {
if (n >= max_count)
return -ENOSPC;
cpuc->event_list[n] = leader;
n++;
}
if (!dogrp)
return n;
list_for_each_entry(event, &leader->sibling_list, group_entry) {
if (!is_x86_event(event) ||
event->state <= PERF_EVENT_STATE_OFF)
continue;
if (n >= max_count)
return -ENOSPC;
cpuc->event_list[n] = event;
n++;
}
return n;
}
static inline void x86_assign_hw_event(struct perf_event *event,
struct cpu_hw_events *cpuc, int i)
{
struct hw_perf_event *hwc = &event->hw;
hwc->idx = cpuc->assign[i];
hwc->last_cpu = smp_processor_id();
hwc->last_tag = ++cpuc->tags[i];
if (hwc->idx == X86_PMC_IDX_FIXED_BTS) {
hwc->config_base = 0;
hwc->event_base = 0;
} else if (hwc->idx >= X86_PMC_IDX_FIXED) {
hwc->config_base = MSR_ARCH_PERFMON_FIXED_CTR_CTRL;
/*
* We set it so that event_base + idx in wrmsr/rdmsr maps to
* MSR_ARCH_PERFMON_FIXED_CTR0 ... CTR2:
*/
hwc->event_base =
MSR_ARCH_PERFMON_FIXED_CTR0 - X86_PMC_IDX_FIXED;
} else {
hwc->config_base = x86_pmu.eventsel;
hwc->event_base = x86_pmu.perfctr;
}
}
static inline int match_prev_assignment(struct hw_perf_event *hwc,
struct cpu_hw_events *cpuc,
int i)
{
return hwc->idx == cpuc->assign[i] &&
hwc->last_cpu == smp_processor_id() &&
hwc->last_tag == cpuc->tags[i];
}
static int x86_pmu_start(struct perf_event *event);
static void x86_pmu_stop(struct perf_event *event);
void hw_perf_enable(void)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
struct perf_event *event;
struct hw_perf_event *hwc;
int i;
if (!x86_pmu_initialized())
return;
if (cpuc->enabled)
return;
if (cpuc->n_added) {
/*
* apply assignment obtained either from
* hw_perf_group_sched_in() or x86_pmu_enable()
*
* step1: save events moving to new counters
* step2: reprogram moved events into new counters
*/
for (i = 0; i < cpuc->n_events; i++) {
event = cpuc->event_list[i];
hwc = &event->hw;
/*
* we can avoid reprogramming counter if:
* - assigned same counter as last time
* - running on same CPU as last time
* - no other event has used the counter since
*/
if (hwc->idx == -1 ||
match_prev_assignment(hwc, cpuc, i))
continue;
x86_pmu_stop(event);
hwc->idx = -1;
}
for (i = 0; i < cpuc->n_events; i++) {
event = cpuc->event_list[i];
hwc = &event->hw;
if (hwc->idx == -1)
x86_assign_hw_event(event, cpuc, i);
x86_pmu_start(event);
}
cpuc->n_added = 0;
perf_events_lapic_init();
}
cpuc->enabled = 1;
barrier();
x86_pmu.enable_all();
}
static inline void __x86_pmu_enable_event(struct hw_perf_event *hwc)
{
(void)checking_wrmsrl(hwc->config_base + hwc->idx,
hwc->config | ARCH_PERFMON_EVENTSEL_ENABLE);
}
static inline void x86_pmu_disable_event(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
(void)checking_wrmsrl(hwc->config_base + hwc->idx, hwc->config);
}
static DEFINE_PER_CPU(u64 [X86_PMC_IDX_MAX], pmc_prev_left);
/*
* Set the next IRQ period, based on the hwc->period_left value.
* To be called with the event disabled in hw:
*/
static int
x86_perf_event_set_period(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
s64 left = atomic64_read(&hwc->period_left);
s64 period = hwc->sample_period;
int err, ret = 0, idx = hwc->idx;
if (idx == X86_PMC_IDX_FIXED_BTS)
return 0;
/*
* If we are way outside a reasonable range then just skip forward:
*/
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;
}
/*
* Quirk: certain CPUs dont like it if just 1 hw_event is left:
*/
if (unlikely(left < 2))
left = 2;
if (left > x86_pmu.max_period)
left = x86_pmu.max_period;
per_cpu(pmc_prev_left[idx], smp_processor_id()) = left;
/*
* The hw event starts counting from this event offset,
* mark it to be able to extra future deltas:
*/
atomic64_set(&hwc->prev_count, (u64)-left);
err = checking_wrmsrl(hwc->event_base + idx,
(u64)(-left) & x86_pmu.event_mask);
perf_event_update_userpage(event);
return ret;
}
static void x86_pmu_enable_event(struct perf_event *event)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
if (cpuc->enabled)
__x86_pmu_enable_event(&event->hw);
}
/*
* activate a single event
*
* The event is added to the group of enabled events
* but only if it can be scehduled with existing events.
*
* Called with PMU disabled. If successful and return value 1,
* then guaranteed to call perf_enable() and hw_perf_enable()
*/
static int x86_pmu_enable(struct perf_event *event)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
struct hw_perf_event *hwc;
int assign[X86_PMC_IDX_MAX];
int n, n0, ret;
hwc = &event->hw;
n0 = cpuc->n_events;
n = collect_events(cpuc, event, false);
if (n < 0)
return n;
ret = x86_schedule_events(cpuc, n, assign);
if (ret)
return ret;
/*
* copy new assignment, now we know it is possible
* will be used by hw_perf_enable()
*/
memcpy(cpuc->assign, assign, n*sizeof(int));
cpuc->n_events = n;
cpuc->n_added = n - n0;
return 0;
}
static int x86_pmu_start(struct perf_event *event)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
int idx = event->hw.idx;
if (idx == -1)
return -EAGAIN;
x86_perf_event_set_period(event);
cpuc->events[idx] = event;
__set_bit(idx, cpuc->active_mask);
x86_pmu.enable(event);
perf_event_update_userpage(event);
return 0;
}
static void x86_pmu_unthrottle(struct perf_event *event)
{
int ret = x86_pmu_start(event);
WARN_ON_ONCE(ret);
}
void perf_event_print_debug(void)
{
u64 ctrl, status, overflow, pmc_ctrl, pmc_count, prev_left, fixed;
struct cpu_hw_events *cpuc;
unsigned long flags;
int cpu, idx;
if (!x86_pmu.num_events)
return;
local_irq_save(flags);
cpu = smp_processor_id();
cpuc = &per_cpu(cpu_hw_events, cpu);
if (x86_pmu.version >= 2) {
rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, ctrl);
rdmsrl(MSR_CORE_PERF_GLOBAL_STATUS, status);
rdmsrl(MSR_CORE_PERF_GLOBAL_OVF_CTRL, overflow);
rdmsrl(MSR_ARCH_PERFMON_FIXED_CTR_CTRL, fixed);
pr_info("\n");
pr_info("CPU#%d: ctrl: %016llx\n", cpu, ctrl);
pr_info("CPU#%d: status: %016llx\n", cpu, status);
pr_info("CPU#%d: overflow: %016llx\n", cpu, overflow);
pr_info("CPU#%d: fixed: %016llx\n", cpu, fixed);
}
pr_info("CPU#%d: active: %016llx\n", cpu, *(u64 *)cpuc->active_mask);
for (idx = 0; idx < x86_pmu.num_events; idx++) {
rdmsrl(x86_pmu.eventsel + idx, pmc_ctrl);
rdmsrl(x86_pmu.perfctr + idx, pmc_count);
prev_left = per_cpu(pmc_prev_left[idx], cpu);
pr_info("CPU#%d: gen-PMC%d ctrl: %016llx\n",
cpu, idx, pmc_ctrl);
pr_info("CPU#%d: gen-PMC%d count: %016llx\n",
cpu, idx, pmc_count);
pr_info("CPU#%d: gen-PMC%d left: %016llx\n",
cpu, idx, prev_left);
}
for (idx = 0; idx < x86_pmu.num_events_fixed; idx++) {
rdmsrl(MSR_ARCH_PERFMON_FIXED_CTR0 + idx, pmc_count);
pr_info("CPU#%d: fixed-PMC%d count: %016llx\n",
cpu, idx, pmc_count);
}
local_irq_restore(flags);
}
static void x86_pmu_stop(struct perf_event *event)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
struct hw_perf_event *hwc = &event->hw;
int idx = hwc->idx;
if (!__test_and_clear_bit(idx, cpuc->active_mask))
return;
x86_pmu.disable(event);
/*
* Drain the remaining delta count out of a event
* that we are disabling:
*/
x86_perf_event_update(event);
cpuc->events[idx] = NULL;
}
static void x86_pmu_disable(struct perf_event *event)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
int i;
x86_pmu_stop(event);
for (i = 0; i < cpuc->n_events; i++) {
if (event == cpuc->event_list[i]) {
if (x86_pmu.put_event_constraints)
x86_pmu.put_event_constraints(cpuc, event);
while (++i < cpuc->n_events)
cpuc->event_list[i-1] = cpuc->event_list[i];
--cpuc->n_events;
break;
}
}
perf_event_update_userpage(event);
}
static int x86_pmu_handle_irq(struct pt_regs *regs)
{
struct perf_sample_data data;
struct cpu_hw_events *cpuc;
struct perf_event *event;
struct hw_perf_event *hwc;
int idx, handled = 0;
u64 val;
perf_sample_data_init(&data, 0);
cpuc = &__get_cpu_var(cpu_hw_events);
for (idx = 0; idx < x86_pmu.num_events; idx++) {
if (!test_bit(idx, cpuc->active_mask))
continue;
event = cpuc->events[idx];
hwc = &event->hw;
val = x86_perf_event_update(event);
if (val & (1ULL << (x86_pmu.event_bits - 1)))
continue;
/*
* event overflow
*/
handled = 1;
data.period = event->hw.last_period;
if (!x86_perf_event_set_period(event))
continue;
if (perf_event_overflow(event, 1, &data, regs))
x86_pmu_stop(event);
}
if (handled)
inc_irq_stat(apic_perf_irqs);
return handled;
}
void smp_perf_pending_interrupt(struct pt_regs *regs)
{
irq_enter();
ack_APIC_irq();
inc_irq_stat(apic_pending_irqs);
perf_event_do_pending();
irq_exit();
}
void set_perf_event_pending(void)
{
#ifdef CONFIG_X86_LOCAL_APIC
if (!x86_pmu.apic || !x86_pmu_initialized())
return;
apic->send_IPI_self(LOCAL_PENDING_VECTOR);
#endif
}
void perf_events_lapic_init(void)
{
#ifdef CONFIG_X86_LOCAL_APIC
if (!x86_pmu.apic || !x86_pmu_initialized())
return;
/*
* Always use NMI for PMU
*/
apic_write(APIC_LVTPC, APIC_DM_NMI);
#endif
}
static int __kprobes
perf_event_nmi_handler(struct notifier_block *self,
unsigned long cmd, void *__args)
{
struct die_args *args = __args;
struct pt_regs *regs;
if (!atomic_read(&active_events))
return NOTIFY_DONE;
switch (cmd) {
case DIE_NMI:
case DIE_NMI_IPI:
break;
default:
return NOTIFY_DONE;
}
regs = args->regs;
#ifdef CONFIG_X86_LOCAL_APIC
apic_write(APIC_LVTPC, APIC_DM_NMI);
#endif
/*
* Can't rely on the handled return value to say it was our NMI, two
* events could trigger 'simultaneously' raising two back-to-back NMIs.
*
* If the first NMI handles both, the latter will be empty and daze
* the CPU.
*/
x86_pmu.handle_irq(regs);
return NOTIFY_STOP;
}
static __read_mostly struct notifier_block perf_event_nmi_notifier = {
.notifier_call = perf_event_nmi_handler,
.next = NULL,
.priority = 1
};
static struct event_constraint unconstrained;
static struct event_constraint emptyconstraint;
static struct event_constraint *
x86_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event)
{
struct event_constraint *c;
if (x86_pmu.event_constraints) {
for_each_event_constraint(c, x86_pmu.event_constraints) {
if ((event->hw.config & c->cmask) == c->code)
return c;
}
}
return &unconstrained;
}
static int x86_event_sched_in(struct perf_event *event,
struct perf_cpu_context *cpuctx)
{
int ret = 0;
event->state = PERF_EVENT_STATE_ACTIVE;
event->oncpu = smp_processor_id();
event->tstamp_running += event->ctx->time - event->tstamp_stopped;
if (!is_x86_event(event))
ret = event->pmu->enable(event);
if (!ret && !is_software_event(event))
cpuctx->active_oncpu++;
if (!ret && event->attr.exclusive)
cpuctx->exclusive = 1;
return ret;
}
static void x86_event_sched_out(struct perf_event *event,
struct perf_cpu_context *cpuctx)
{
event->state = PERF_EVENT_STATE_INACTIVE;
event->oncpu = -1;
if (!is_x86_event(event))
event->pmu->disable(event);
event->tstamp_running -= event->ctx->time - event->tstamp_stopped;
if (!is_software_event(event))
cpuctx->active_oncpu--;
if (event->attr.exclusive || !cpuctx->active_oncpu)
cpuctx->exclusive = 0;
}
/*
* Called to enable a whole group of events.
* Returns 1 if the group was enabled, or -EAGAIN if it could not be.
* Assumes the caller has disabled interrupts and has
* frozen the PMU with hw_perf_save_disable.
*
* called with PMU disabled. If successful and return value 1,
* then guaranteed to call perf_enable() and hw_perf_enable()
*/
int hw_perf_group_sched_in(struct perf_event *leader,
struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
struct perf_event *sub;
int assign[X86_PMC_IDX_MAX];
int n0, n1, ret;
/* n0 = total number of events */
n0 = collect_events(cpuc, leader, true);
if (n0 < 0)
return n0;
ret = x86_schedule_events(cpuc, n0, assign);
if (ret)
return ret;
ret = x86_event_sched_in(leader, cpuctx);
if (ret)
return ret;
n1 = 1;
list_for_each_entry(sub, &leader->sibling_list, group_entry) {
if (sub->state > PERF_EVENT_STATE_OFF) {
ret = x86_event_sched_in(sub, cpuctx);
if (ret)
goto undo;
++n1;
}
}
/*
* copy new assignment, now we know it is possible
* will be used by hw_perf_enable()
*/
memcpy(cpuc->assign, assign, n0*sizeof(int));
cpuc->n_events = n0;
cpuc->n_added = n1;
ctx->nr_active += n1;
/*
* 1 means successful and events are active
* This is not quite true because we defer
* actual activation until hw_perf_enable() but
* this way we* ensure caller won't try to enable
* individual events
*/
return 1;
undo:
x86_event_sched_out(leader, cpuctx);
n0 = 1;
list_for_each_entry(sub, &leader->sibling_list, group_entry) {
if (sub->state == PERF_EVENT_STATE_ACTIVE) {
x86_event_sched_out(sub, cpuctx);
if (++n0 == n1)
break;
}
}
return ret;
}
#include "perf_event_amd.c"
#include "perf_event_p6.c"
#include "perf_event_intel.c"
static int __cpuinit
x86_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:
if (x86_pmu.cpu_prepare)
x86_pmu.cpu_prepare(cpu);
break;
case CPU_STARTING:
if (x86_pmu.cpu_starting)
x86_pmu.cpu_starting(cpu);
break;
case CPU_DYING:
if (x86_pmu.cpu_dying)
x86_pmu.cpu_dying(cpu);
break;
case CPU_DEAD:
if (x86_pmu.cpu_dead)
x86_pmu.cpu_dead(cpu);
break;
default:
break;
}
return NOTIFY_OK;
}
static void __init pmu_check_apic(void)
{
if (cpu_has_apic)
return;
x86_pmu.apic = 0;
pr_info("no APIC, boot with the \"lapic\" boot parameter to force-enable it.\n");
pr_info("no hardware sampling interrupt available.\n");
}
void __init init_hw_perf_events(void)
{
struct event_constraint *c;
int err;
pr_info("Performance Events: ");
switch (boot_cpu_data.x86_vendor) {
case X86_VENDOR_INTEL:
err = intel_pmu_init();
break;
case X86_VENDOR_AMD:
err = amd_pmu_init();
break;
default:
return;
}
if (err != 0) {
pr_cont("no PMU driver, software events only.\n");
return;
}
pmu_check_apic();
pr_cont("%s PMU driver.\n", x86_pmu.name);
if (x86_pmu.num_events > X86_PMC_MAX_GENERIC) {
WARN(1, KERN_ERR "hw perf events %d > max(%d), clipping!",
x86_pmu.num_events, X86_PMC_MAX_GENERIC);
x86_pmu.num_events = X86_PMC_MAX_GENERIC;
}
perf_event_mask = (1 << x86_pmu.num_events) - 1;
perf_max_events = x86_pmu.num_events;
if (x86_pmu.num_events_fixed > X86_PMC_MAX_FIXED) {
WARN(1, KERN_ERR "hw perf events fixed %d > max(%d), clipping!",
x86_pmu.num_events_fixed, X86_PMC_MAX_FIXED);
x86_pmu.num_events_fixed = X86_PMC_MAX_FIXED;
}
perf_event_mask |=
((1LL << x86_pmu.num_events_fixed)-1) << X86_PMC_IDX_FIXED;
x86_pmu.intel_ctrl = perf_event_mask;
perf_events_lapic_init();
register_die_notifier(&perf_event_nmi_notifier);
unconstrained = (struct event_constraint)
__EVENT_CONSTRAINT(0, (1ULL << x86_pmu.num_events) - 1,
0, x86_pmu.num_events);
if (x86_pmu.event_constraints) {
for_each_event_constraint(c, x86_pmu.event_constraints) {
if (c->cmask != INTEL_ARCH_FIXED_MASK)
continue;
c->idxmsk64 |= (1ULL << x86_pmu.num_events) - 1;
c->weight += x86_pmu.num_events;
}
}
pr_info("... version: %d\n", x86_pmu.version);
pr_info("... bit width: %d\n", x86_pmu.event_bits);
pr_info("... generic registers: %d\n", x86_pmu.num_events);
pr_info("... value mask: %016Lx\n", x86_pmu.event_mask);
pr_info("... max period: %016Lx\n", x86_pmu.max_period);
pr_info("... fixed-purpose events: %d\n", x86_pmu.num_events_fixed);
pr_info("... event mask: %016Lx\n", perf_event_mask);
perf_cpu_notifier(x86_pmu_notifier);
}
static inline void x86_pmu_read(struct perf_event *event)
{
x86_perf_event_update(event);
}
static const struct pmu pmu = {
.enable = x86_pmu_enable,
.disable = x86_pmu_disable,
.start = x86_pmu_start,
.stop = x86_pmu_stop,
.read = x86_pmu_read,
.unthrottle = x86_pmu_unthrottle,
};
/*
* validate a single event group
*
* validation include:
* - check events are compatible which each other
* - events do not compete for the same counter
* - number of events <= number of counters
*
* validation ensures the group can be loaded onto the
* PMU if it was the only group available.
*/
static int validate_group(struct perf_event *event)
{
struct perf_event *leader = event->group_leader;
struct cpu_hw_events *fake_cpuc;
int ret, n;
ret = -ENOMEM;
fake_cpuc = kmalloc(sizeof(*fake_cpuc), GFP_KERNEL | __GFP_ZERO);
if (!fake_cpuc)
goto out;
/*
* the event is not yet connected with its
* siblings therefore we must first collect
* existing siblings, then add the new event
* before we can simulate the scheduling
*/
ret = -ENOSPC;
n = collect_events(fake_cpuc, leader, true);
if (n < 0)
goto out_free;
fake_cpuc->n_events = n;
n = collect_events(fake_cpuc, event, false);
if (n < 0)
goto out_free;
fake_cpuc->n_events = n;
ret = x86_schedule_events(fake_cpuc, n, NULL);
out_free:
kfree(fake_cpuc);
out:
return ret;
}
const struct pmu *hw_perf_event_init(struct perf_event *event)
{
const struct pmu *tmp;
int err;
err = __hw_perf_event_init(event);
if (!err) {
/*
* we temporarily connect event to its pmu
* such that validate_group() can classify
* it as an x86 event using is_x86_event()
*/
tmp = event->pmu;
event->pmu = &pmu;
if (event->group_leader != event)
err = validate_group(event);
event->pmu = tmp;
}
if (err) {
if (event->destroy)
event->destroy(event);
return ERR_PTR(err);
}
return &pmu;
}
/*
* callchain support
*/
static inline
void callchain_store(struct perf_callchain_entry *entry, u64 ip)
{
if (entry->nr < PERF_MAX_STACK_DEPTH)
entry->ip[entry->nr++] = ip;
}
static DEFINE_PER_CPU(struct perf_callchain_entry, pmc_irq_entry);
static DEFINE_PER_CPU(struct perf_callchain_entry, pmc_nmi_entry);
static void
backtrace_warning_symbol(void *data, char *msg, unsigned long symbol)
{
/* Ignore warnings */
}
static void backtrace_warning(void *data, char *msg)
{
/* Ignore warnings */
}
static int backtrace_stack(void *data, char *name)
{
return 0;
}
static void backtrace_address(void *data, unsigned long addr, int reliable)
{
struct perf_callchain_entry *entry = data;
if (reliable)
callchain_store(entry, addr);
}
static const struct stacktrace_ops backtrace_ops = {
.warning = backtrace_warning,
.warning_symbol = backtrace_warning_symbol,
.stack = backtrace_stack,
.address = backtrace_address,
.walk_stack = print_context_stack_bp,
};
#include "../dumpstack.h"
static void
perf_callchain_kernel(struct pt_regs *regs, struct perf_callchain_entry *entry)
{
callchain_store(entry, PERF_CONTEXT_KERNEL);
callchain_store(entry, regs->ip);
dump_trace(NULL, regs, NULL, regs->bp, &backtrace_ops, entry);
}
/*
* best effort, GUP based copy_from_user() that assumes IRQ or NMI context
*/
static unsigned long
copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
{
unsigned long offset, addr = (unsigned long)from;
int type = in_nmi() ? KM_NMI : KM_IRQ0;
unsigned long size, len = 0;
struct page *page;
void *map;
int ret;
do {
ret = __get_user_pages_fast(addr, 1, 0, &page);
if (!ret)
break;
offset = addr & (PAGE_SIZE - 1);
size = min(PAGE_SIZE - offset, n - len);
map = kmap_atomic(page, type);
memcpy(to, map+offset, size);
kunmap_atomic(map, type);
put_page(page);
len += size;
to += size;
addr += size;
} while (len < n);
return len;
}
static int copy_stack_frame(const void __user *fp, struct stack_frame *frame)
{
unsigned long bytes;
bytes = copy_from_user_nmi(frame, fp, sizeof(*frame));
return bytes == sizeof(*frame);
}
static void
perf_callchain_user(struct pt_regs *regs, struct perf_callchain_entry *entry)
{
struct stack_frame frame;
const void __user *fp;
if (!user_mode(regs))
regs = task_pt_regs(current);
fp = (void __user *)regs->bp;
callchain_store(entry, PERF_CONTEXT_USER);
callchain_store(entry, regs->ip);
while (entry->nr < PERF_MAX_STACK_DEPTH) {
frame.next_frame = NULL;
frame.return_address = 0;
if (!copy_stack_frame(fp, &frame))
break;
if ((unsigned long)fp < regs->sp)
break;
callchain_store(entry, frame.return_address);
fp = frame.next_frame;
}
}
static void
perf_do_callchain(struct pt_regs *regs, struct perf_callchain_entry *entry)
{
int is_user;
if (!regs)
return;
is_user = user_mode(regs);
if (is_user && current->state != TASK_RUNNING)
return;
if (!is_user)
perf_callchain_kernel(regs, entry);
if (current->mm)
perf_callchain_user(regs, entry);
}
struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
{
struct perf_callchain_entry *entry;
if (in_nmi())
entry = &__get_cpu_var(pmc_nmi_entry);
else
entry = &__get_cpu_var(pmc_irq_entry);
entry->nr = 0;
perf_do_callchain(regs, entry);
return entry;
}
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