- 根目录:
- arch
- x86
- kernel
- cpu
- perf_event.c
/*
* 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/slab.h>
#include <linux/cpu.h>
#include <linux/bitops.h>
#include <linux/device.h>
#include <asm/apic.h>
#include <asm/stacktrace.h>
#include <asm/nmi.h>
#include <asm/smp.h>
#include <asm/alternative.h>
#include <asm/mmu_context.h>
#include <asm/tlbflush.h>
#include <asm/timer.h>
#include <asm/desc.h>
#include <asm/ldt.h>
#include "perf_event.h"
struct x86_pmu x86_pmu __read_mostly;
DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = {
.enabled = 1,
};
struct static_key rdpmc_always_available = STATIC_KEY_INIT_FALSE;
u64 __read_mostly hw_cache_event_ids
[PERF_COUNT_HW_CACHE_MAX]
[PERF_COUNT_HW_CACHE_OP_MAX]
[PERF_COUNT_HW_CACHE_RESULT_MAX];
u64 __read_mostly hw_cache_extra_regs
[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.
*/
u64 x86_perf_event_update(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
int shift = 64 - x86_pmu.cntval_bits;
u64 prev_raw_count, new_raw_count;
int idx = hwc->idx;
s64 delta;
if (idx == INTEL_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 = local64_read(&hwc->prev_count);
rdpmcl(hwc->event_base_rdpmc, new_raw_count);
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
* (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;
local64_add(delta, &event->count);
local64_sub(delta, &hwc->period_left);
return new_raw_count;
}
/*
* Find and validate any extra registers to set up.
*/
static int x86_pmu_extra_regs(u64 config, struct perf_event *event)
{
struct hw_perf_event_extra *reg;
struct extra_reg *er;
reg = &event->hw.extra_reg;
if (!x86_pmu.extra_regs)
return 0;
for (er = x86_pmu.extra_regs; er->msr; er++) {
if (er->event != (config & er->config_mask))
continue;
if (event->attr.config1 & ~er->valid_mask)
return -EINVAL;
/* Check if the extra msrs can be safely accessed*/
if (!er->extra_msr_access)
return -ENXIO;
reg->idx = er->idx;
reg->config = event->attr.config1;
reg->reg = er->msr;
break;
}
return 0;
}
static atomic_t active_events;
static DEFINE_MUTEX(pmc_reserve_mutex);
#ifdef CONFIG_X86_LOCAL_APIC
static bool reserve_pmc_hardware(void)
{
int i;
for (i = 0; i < x86_pmu.num_counters; i++) {
if (!reserve_perfctr_nmi(x86_pmu_event_addr(i)))
goto perfctr_fail;
}
for (i = 0; i < x86_pmu.num_counters; i++) {
if (!reserve_evntsel_nmi(x86_pmu_config_addr(i)))
goto eventsel_fail;
}
return true;
eventsel_fail:
for (i--; i >= 0; i--)
release_evntsel_nmi(x86_pmu_config_addr(i));
i = x86_pmu.num_counters;
perfctr_fail:
for (i--; i >= 0; i--)
release_perfctr_nmi(x86_pmu_event_addr(i));
return false;
}
static void release_pmc_hardware(void)
{
int i;
for (i = 0; i < x86_pmu.num_counters; i++) {
release_perfctr_nmi(x86_pmu_event_addr(i));
release_evntsel_nmi(x86_pmu_config_addr(i));
}
}
#else
static bool reserve_pmc_hardware(void) { return true; }
static void release_pmc_hardware(void) {}
#endif
static bool check_hw_exists(void)
{
u64 val, val_fail, val_new= ~0;
int i, reg, reg_fail, ret = 0;
int bios_fail = 0;
int reg_safe = -1;
/*
* Check to see if the BIOS enabled any of the counters, if so
* complain and bail.
*/
for (i = 0; i < x86_pmu.num_counters; i++) {
reg = x86_pmu_config_addr(i);
ret = rdmsrl_safe(reg, &val);
if (ret)
goto msr_fail;
if (val & ARCH_PERFMON_EVENTSEL_ENABLE) {
bios_fail = 1;
val_fail = val;
reg_fail = reg;
} else {
reg_safe = i;
}
}
if (x86_pmu.num_counters_fixed) {
reg = MSR_ARCH_PERFMON_FIXED_CTR_CTRL;
ret = rdmsrl_safe(reg, &val);
if (ret)
goto msr_fail;
for (i = 0; i < x86_pmu.num_counters_fixed; i++) {
if (val & (0x03 << i*4)) {
bios_fail = 1;
val_fail = val;
reg_fail = reg;
}
}
}
/*
* If all the counters are enabled, the below test will always
* fail. The tools will also become useless in this scenario.
* Just fail and disable the hardware counters.
*/
if (reg_safe == -1) {
reg = reg_safe;
goto msr_fail;
}
/*
* Read the current value, change it and read it back to see if it
* matches, this is needed to detect certain hardware emulators
* (qemu/kvm) that don't trap on the MSR access and always return 0s.
*/
reg = x86_pmu_event_addr(reg_safe);
if (rdmsrl_safe(reg, &val))
goto msr_fail;
val ^= 0xffffUL;
ret = wrmsrl_safe(reg, val);
ret |= rdmsrl_safe(reg, &val_new);
if (ret || val != val_new)
goto msr_fail;
/*
* We still allow the PMU driver to operate:
*/
if (bios_fail) {
printk(KERN_CONT "Broken BIOS detected, complain to your hardware vendor.\n");
printk(KERN_ERR FW_BUG "the BIOS has corrupted hw-PMU resources (MSR %x is %Lx)\n", reg_fail, val_fail);
}
return true;
msr_fail:
printk(KERN_CONT "Broken PMU hardware detected, using software events only.\n");
printk("%sFailed to access perfctr msr (MSR %x is %Lx)\n",
boot_cpu_has(X86_FEATURE_HYPERVISOR) ? KERN_INFO : KERN_ERR,
reg, val_new);
return false;
}
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_ds_buffers();
mutex_unlock(&pmc_reserve_mutex);
}
}
void hw_perf_lbr_event_destroy(struct perf_event *event)
{
hw_perf_event_destroy(event);
/* undo the lbr/bts event accounting */
x86_del_exclusive(x86_lbr_exclusive_lbr);
}
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 *event)
{
struct perf_event_attr *attr = &event->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;
attr->config1 = hw_cache_extra_regs[cache_type][cache_op][cache_result];
return x86_pmu_extra_regs(val, event);
}
/*
* Check if we can create event of a certain type (that no conflicting events
* are present).
*/
int x86_add_exclusive(unsigned int what)
{
int ret = -EBUSY, i;
if (atomic_inc_not_zero(&x86_pmu.lbr_exclusive[what]))
return 0;
mutex_lock(&pmc_reserve_mutex);
for (i = 0; i < ARRAY_SIZE(x86_pmu.lbr_exclusive); i++)
if (i != what && atomic_read(&x86_pmu.lbr_exclusive[i]))
goto out;
atomic_inc(&x86_pmu.lbr_exclusive[what]);
ret = 0;
out:
mutex_unlock(&pmc_reserve_mutex);
return ret;
}
void x86_del_exclusive(unsigned int what)
{
atomic_dec(&x86_pmu.lbr_exclusive[what]);
}
int x86_setup_perfctr(struct perf_event *event)
{
struct perf_event_attr *attr = &event->attr;
struct hw_perf_event *hwc = &event->hw;
u64 config;
if (!is_sampling_event(event)) {
hwc->sample_period = x86_pmu.max_period;
hwc->last_period = hwc->sample_period;
local64_set(&hwc->period_left, hwc->sample_period);
}
if (attr->type == PERF_TYPE_RAW)
return x86_pmu_extra_regs(event->attr.config, event);
if (attr->type == PERF_TYPE_HW_CACHE)
return set_ext_hw_attr(hwc, event);
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 &&
!attr->freq && hwc->sample_period == 1) {
/* BTS is not supported by this architecture. */
if (!x86_pmu.bts_active)
return -EOPNOTSUPP;
/* BTS is currently only allowed for user-mode. */
if (!attr->exclude_kernel)
return -EOPNOTSUPP;
/* disallow bts if conflicting events are present */
if (x86_add_exclusive(x86_lbr_exclusive_lbr))
return -EBUSY;
event->destroy = hw_perf_lbr_event_destroy;
}
hwc->config |= config;
return 0;
}
/*
* check that branch_sample_type is compatible with
* settings needed for precise_ip > 1 which implies
* using the LBR to capture ALL taken branches at the
* priv levels of the measurement
*/
static inline int precise_br_compat(struct perf_event *event)
{
u64 m = event->attr.branch_sample_type;
u64 b = 0;
/* must capture all branches */
if (!(m & PERF_SAMPLE_BRANCH_ANY))
return 0;
m &= PERF_SAMPLE_BRANCH_KERNEL | PERF_SAMPLE_BRANCH_USER;
if (!event->attr.exclude_user)
b |= PERF_SAMPLE_BRANCH_USER;
if (!event->attr.exclude_kernel)
b |= PERF_SAMPLE_BRANCH_KERNEL;
/*
* ignore PERF_SAMPLE_BRANCH_HV, not supported on x86
*/
return m == b;
}
int x86_pmu_hw_config(struct perf_event *event)
{
if (event->attr.precise_ip) {
int precise = 0;
/* Support for constant skid */
if (x86_pmu.pebs_active && !x86_pmu.pebs_broken) {
precise++;
/* Support for IP fixup */
if (x86_pmu.lbr_nr || x86_pmu.intel_cap.pebs_format >= 2)
precise++;
}
if (event->attr.precise_ip > precise)
return -EOPNOTSUPP;
}
/*
* check that PEBS LBR correction does not conflict with
* whatever the user is asking with attr->branch_sample_type
*/
if (event->attr.precise_ip > 1 && x86_pmu.intel_cap.pebs_format < 2) {
u64 *br_type = &event->attr.branch_sample_type;
if (has_branch_stack(event)) {
if (!precise_br_compat(event))
return -EOPNOTSUPP;
/* branch_sample_type is compatible */
} else {
/*
* user did not specify branch_sample_type
*
* For PEBS fixups, we capture all
* the branches at the priv level of the
* event.
*/
*br_type = PERF_SAMPLE_BRANCH_ANY;
if (!event->attr.exclude_user)
*br_type |= PERF_SAMPLE_BRANCH_USER;
if (!event->attr.exclude_kernel)
*br_type |= PERF_SAMPLE_BRANCH_KERNEL;
}
}
if (event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_CALL_STACK)
event->attach_state |= PERF_ATTACH_TASK_DATA;
/*
* Generate PMC IRQs:
* (keep 'enabled' bit clear for now)
*/
event->hw.config = ARCH_PERFMON_EVENTSEL_INT;
/*
* Count user and OS events unless requested not to
*/
if (!event->attr.exclude_user)
event->hw.config |= ARCH_PERFMON_EVENTSEL_USR;
if (!event->attr.exclude_kernel)
event->hw.config |= ARCH_PERFMON_EVENTSEL_OS;
if (event->attr.type == PERF_TYPE_RAW)
event->hw.config |= event->attr.config & X86_RAW_EVENT_MASK;
if (event->attr.sample_period && x86_pmu.limit_period) {
if (x86_pmu.limit_period(event, event->attr.sample_period) >
event->attr.sample_period)
return -EINVAL;
}
return x86_setup_perfctr(event);
}
/*
* Setup the hardware configuration for a given attr_type
*/
static int __x86_pmu_event_init(struct perf_event *event)
{
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
reserve_ds_buffers();
}
if (!err)
atomic_inc(&active_events);
mutex_unlock(&pmc_reserve_mutex);
}
if (err)
return err;
event->destroy = hw_perf_event_destroy;
event->hw.idx = -1;
event->hw.last_cpu = -1;
event->hw.last_tag = ~0ULL;
/* mark unused */
event->hw.extra_reg.idx = EXTRA_REG_NONE;
event->hw.branch_reg.idx = EXTRA_REG_NONE;
return x86_pmu.hw_config(event);
}
void x86_pmu_disable_all(void)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
int idx;
for (idx = 0; idx < x86_pmu.num_counters; idx++) {
u64 val;
if (!test_bit(idx, cpuc->active_mask))
continue;
rdmsrl(x86_pmu_config_addr(idx), val);
if (!(val & ARCH_PERFMON_EVENTSEL_ENABLE))
continue;
val &= ~ARCH_PERFMON_EVENTSEL_ENABLE;
wrmsrl(x86_pmu_config_addr(idx), val);
}
}
static void x86_pmu_disable(struct pmu *pmu)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
if (!x86_pmu_initialized())
return;
if (!cpuc->enabled)
return;
cpuc->n_added = 0;
cpuc->enabled = 0;
barrier();
x86_pmu.disable_all();
}
void x86_pmu_enable_all(int added)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
int idx;
for (idx = 0; idx < x86_pmu.num_counters; idx++) {
struct hw_perf_event *hwc = &cpuc->events[idx]->hw;
if (!test_bit(idx, cpuc->active_mask))
continue;
__x86_pmu_enable_event(hwc, ARCH_PERFMON_EVENTSEL_ENABLE);
}
}
static struct pmu pmu;
static inline int is_x86_event(struct perf_event *event)
{
return event->pmu == &pmu;
}
/*
* Event scheduler state:
*
* Assign events iterating over all events and counters, beginning
* with events with least weights first. Keep the current iterator
* state in struct sched_state.
*/
struct sched_state {
int weight;
int event; /* event index */
int counter; /* counter index */
int unassigned; /* number of events to be assigned left */
int nr_gp; /* number of GP counters used */
unsigned long used[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
};
/* Total max is X86_PMC_IDX_MAX, but we are O(n!) limited */
#define SCHED_STATES_MAX 2
struct perf_sched {
int max_weight;
int max_events;
int max_gp;
int saved_states;
struct event_constraint **constraints;
struct sched_state state;
struct sched_state saved[SCHED_STATES_MAX];
};
/*
* Initialize interator that runs through all events and counters.
*/
static void perf_sched_init(struct perf_sched *sched, struct event_constraint **constraints,
int num, int wmin, int wmax, int gpmax)
{
int idx;
memset(sched, 0, sizeof(*sched));
sched->max_events = num;
sched->max_weight = wmax;
sched->max_gp = gpmax;
sched->constraints = constraints;
for (idx = 0; idx < num; idx++) {
if (constraints[idx]->weight == wmin)
break;
}
sched->state.event = idx; /* start with min weight */
sched->state.weight = wmin;
sched->state.unassigned = num;
}
static void perf_sched_save_state(struct perf_sched *sched)
{
if (WARN_ON_ONCE(sched->saved_states >= SCHED_STATES_MAX))
return;
sched->saved[sched->saved_states] = sched->state;
sched->saved_states++;
}
static bool perf_sched_restore_state(struct perf_sched *sched)
{
if (!sched->saved_states)
return false;
sched->saved_states--;
sched->state = sched->saved[sched->saved_states];
/* continue with next counter: */
clear_bit(sched->state.counter++, sched->state.used);
return true;
}
/*
* Select a counter for the current event to schedule. Return true on
* success.
*/
static bool __perf_sched_find_counter(struct perf_sched *sched)
{
struct event_constraint *c;
int idx;
if (!sched->state.unassigned)
return false;
if (sched->state.event >= sched->max_events)
return false;
c = sched->constraints[sched->state.event];
/* Prefer fixed purpose counters */
if (c->idxmsk64 & (~0ULL << INTEL_PMC_IDX_FIXED)) {
idx = INTEL_PMC_IDX_FIXED;
for_each_set_bit_from(idx, c->idxmsk, X86_PMC_IDX_MAX) {
if (!__test_and_set_bit(idx, sched->state.used))
goto done;
}
}
/* Grab the first unused counter starting with idx */
idx = sched->state.counter;
for_each_set_bit_from(idx, c->idxmsk, INTEL_PMC_IDX_FIXED) {
if (!__test_and_set_bit(idx, sched->state.used)) {
if (sched->state.nr_gp++ >= sched->max_gp)
return false;
goto done;
}
}
return false;
done:
sched->state.counter = idx;
if (c->overlap)
perf_sched_save_state(sched);
return true;
}
static bool perf_sched_find_counter(struct perf_sched *sched)
{
while (!__perf_sched_find_counter(sched)) {
if (!perf_sched_restore_state(sched))
return false;
}
return true;
}
/*
* Go through all unassigned events and find the next one to schedule.
* Take events with the least weight first. Return true on success.
*/
static bool perf_sched_next_event(struct perf_sched *sched)
{
struct event_constraint *c;
if (!sched->state.unassigned || !--sched->state.unassigned)
return false;
do {
/* next event */
sched->state.event++;
if (sched->state.event >= sched->max_events) {
/* next weight */
sched->state.event = 0;
sched->state.weight++;
if (sched->state.weight > sched->max_weight)
return false;
}
c = sched->constraints[sched->state.event];
} while (c->weight != sched->state.weight);
sched->state.counter = 0; /* start with first counter */
return true;
}
/*
* Assign a counter for each event.
*/
int perf_assign_events(struct event_constraint **constraints, int n,
int wmin, int wmax, int gpmax, int *assign)
{
struct perf_sched sched;
perf_sched_init(&sched, constraints, n, wmin, wmax, gpmax);
do {
if (!perf_sched_find_counter(&sched))
break; /* failed */
if (assign)
assign[sched.state.event] = sched.state.counter;
} while (perf_sched_next_event(&sched));
return sched.state.unassigned;
}
EXPORT_SYMBOL_GPL(perf_assign_events);
int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign)
{
struct event_constraint *c;
unsigned long used_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
struct perf_event *e;
int i, wmin, wmax, unsched = 0;
struct hw_perf_event *hwc;
bitmap_zero(used_mask, X86_PMC_IDX_MAX);
if (x86_pmu.start_scheduling)
x86_pmu.start_scheduling(cpuc);
for (i = 0, wmin = X86_PMC_IDX_MAX, wmax = 0; i < n; i++) {
cpuc->event_constraint[i] = NULL;
c = x86_pmu.get_event_constraints(cpuc, i, cpuc->event_list[i]);
cpuc->event_constraint[i] = c;
wmin = min(wmin, c->weight);
wmax = max(wmax, c->weight);
}
/*
* fastpath, try to reuse previous register
*/
for (i = 0; i < n; i++) {
hwc = &cpuc->event_list[i]->hw;
c = cpuc->event_constraint[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;
}
/* slow path */
if (i != n) {
int gpmax = x86_pmu.num_counters;
/*
* Do not allow scheduling of more than half the available
* generic counters.
*
* This helps avoid counter starvation of sibling thread by
* ensuring at most half the counters cannot be in exclusive
* mode. There is no designated counters for the limits. Any
* N/2 counters can be used. This helps with events with
* specific counter constraints.
*/
if (is_ht_workaround_enabled() && !cpuc->is_fake &&
READ_ONCE(cpuc->excl_cntrs->exclusive_present))
gpmax /= 2;
unsched = perf_assign_events(cpuc->event_constraint, n, wmin,
wmax, gpmax, assign);
}
/*
* In case of success (unsched = 0), mark events as committed,
* so we do not put_constraint() in case new events are added
* and fail to be scheduled
*
* We invoke the lower level commit callback to lock the resource
*
* We do not need to do all of this in case we are called to
* validate an event group (assign == NULL)
*/
if (!unsched && assign) {
for (i = 0; i < n; i++) {
e = cpuc->event_list[i];
e->hw.flags |= PERF_X86_EVENT_COMMITTED;
if (x86_pmu.commit_scheduling)
x86_pmu.commit_scheduling(cpuc, i, assign[i]);
}
}
if (!assign || unsched) {
for (i = 0; i < n; i++) {
e = cpuc->event_list[i];
/*
* do not put_constraint() on comitted events,
* because they are good to go
*/
if ((e->hw.flags & PERF_X86_EVENT_COMMITTED))
continue;
/*
* release events that failed scheduling
*/
if (x86_pmu.put_event_constraints)
x86_pmu.put_event_constraints(cpuc, e);
}
}
if (x86_pmu.stop_scheduling)
x86_pmu.stop_scheduling(cpuc);
return unsched ? -EINVAL : 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_counters + x86_pmu.num_counters_fixed;
/* current number of events already accepted */
n = cpuc->n_events;
if (is_x86_event(leader)) {
if (n >= max_count)
return -EINVAL;
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 -EINVAL;
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 == INTEL_PMC_IDX_FIXED_BTS) {
hwc->config_base = 0;
hwc->event_base = 0;
} else if (hwc->idx >= INTEL_PMC_IDX_FIXED) {
hwc->config_base = MSR_ARCH_PERFMON_FIXED_CTR_CTRL;
hwc->event_base = MSR_ARCH_PERFMON_FIXED_CTR0 + (hwc->idx - INTEL_PMC_IDX_FIXED);
hwc->event_base_rdpmc = (hwc->idx - INTEL_PMC_IDX_FIXED) | 1<<30;
} else {
hwc->config_base = x86_pmu_config_addr(hwc->idx);
hwc->event_base = x86_pmu_event_addr(hwc->idx);
hwc->event_base_rdpmc = x86_pmu_rdpmc_index(hwc->idx);
}
}
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 void x86_pmu_start(struct perf_event *event, int flags);
static void x86_pmu_enable(struct pmu *pmu)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
struct perf_event *event;
struct hw_perf_event *hwc;
int i, added = cpuc->n_added;
if (!x86_pmu_initialized())
return;
if (cpuc->enabled)
return;
if (cpuc->n_added) {
int n_running = cpuc->n_events - cpuc->n_added;
/*
* apply assignment obtained either from
* hw_perf_group_sched_in() or x86_pmu_enable()
*
* step1: save events moving to new counters
*/
for (i = 0; i < n_running; 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;
/*
* Ensure we don't accidentally enable a stopped
* counter simply because we rescheduled.
*/
if (hwc->state & PERF_HES_STOPPED)
hwc->state |= PERF_HES_ARCH;
x86_pmu_stop(event, PERF_EF_UPDATE);
}
/*
* step2: reprogram moved events into new counters
*/
for (i = 0; i < cpuc->n_events; i++) {
event = cpuc->event_list[i];
hwc = &event->hw;
if (!match_prev_assignment(hwc, cpuc, i))
x86_assign_hw_event(event, cpuc, i);
else if (i < n_running)
continue;
if (hwc->state & PERF_HES_ARCH)
continue;
x86_pmu_start(event, PERF_EF_RELOAD);
}
cpuc->n_added = 0;
perf_events_lapic_init();
}
cpuc->enabled = 1;
barrier();
x86_pmu.enable_all(added);
}
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:
*/
int x86_perf_event_set_period(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
s64 left = local64_read(&hwc->period_left);
s64 period = hwc->sample_period;
int ret = 0, idx = hwc->idx;
if (idx == INTEL_PMC_IDX_FIXED_BTS)
return 0;
/*
* If we are way outside a reasonable range then just skip forward:
*/
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;
}
/*
* 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;
if (x86_pmu.limit_period)
left = x86_pmu.limit_period(event, left);
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:
*/
local64_set(&hwc->prev_count, (u64)-left);
wrmsrl(hwc->event_base, (u64)(-left) & x86_pmu.cntval_mask);
/*
* Due to erratum on certan cpu we need
* a second write to be sure the register
* is updated properly
*/
if (x86_pmu.perfctr_second_write) {
wrmsrl(hwc->event_base,
(u64)(-left) & x86_pmu.cntval_mask);
}
perf_event_update_userpage(event);
return ret;
}
void x86_pmu_enable_event(struct perf_event *event)
{
if (__this_cpu_read(cpu_hw_events.enabled))
__x86_pmu_enable_event(&event->hw,
ARCH_PERFMON_EVENTSEL_ENABLE);
}
/*
* Add a single event to the PMU.
*
* The event is added to the group of enabled events
* but only if it can be scehduled with existing events.
*/
static int x86_pmu_add(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&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;
ret = n = collect_events(cpuc, event, false);
if (ret < 0)
goto out;
hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
if (!(flags & PERF_EF_START))
hwc->state |= PERF_HES_ARCH;
/*
* If group events scheduling transaction was started,
* skip the schedulability test here, it will be performed
* at commit time (->commit_txn) as a whole.
*/
if (cpuc->group_flag & PERF_EVENT_TXN)
goto done_collect;
ret = x86_pmu.schedule_events(cpuc, n, assign);
if (ret)
goto out;
/*
* copy new assignment, now we know it is possible
* will be used by hw_perf_enable()
*/
memcpy(cpuc->assign, assign, n*sizeof(int));
done_collect:
/*
* Commit the collect_events() state. See x86_pmu_del() and
* x86_pmu_*_txn().
*/
cpuc->n_events = n;
cpuc->n_added += n - n0;
cpuc->n_txn += n - n0;
ret = 0;
out:
return ret;
}
static void x86_pmu_start(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
int idx = event->hw.idx;
if (WARN_ON_ONCE(!(event->hw.state & PERF_HES_STOPPED)))
return;
if (WARN_ON_ONCE(idx == -1))
return;
if (flags & PERF_EF_RELOAD) {
WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
x86_perf_event_set_period(event);
}
event->hw.state = 0;
cpuc->events[idx] = event;
__set_bit(idx, cpuc->active_mask);
__set_bit(idx, cpuc->running);
x86_pmu.enable(event);
perf_event_update_userpage(event);
}
void perf_event_print_debug(void)
{
u64 ctrl, status, overflow, pmc_ctrl, pmc_count, prev_left, fixed;
u64 pebs, debugctl;
struct cpu_hw_events *cpuc;
unsigned long flags;
int cpu, idx;
if (!x86_pmu.num_counters)
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);
if (x86_pmu.pebs_constraints) {
rdmsrl(MSR_IA32_PEBS_ENABLE, pebs);
pr_info("CPU#%d: pebs: %016llx\n", cpu, pebs);
}
if (x86_pmu.lbr_nr) {
rdmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
pr_info("CPU#%d: debugctl: %016llx\n", cpu, debugctl);
}
}
pr_info("CPU#%d: active: %016llx\n", cpu, *(u64 *)cpuc->active_mask);
for (idx = 0; idx < x86_pmu.num_counters; idx++) {
rdmsrl(x86_pmu_config_addr(idx), pmc_ctrl);
rdmsrl(x86_pmu_event_addr(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_counters_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);
}
void x86_pmu_stop(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
struct hw_perf_event *hwc = &event->hw;
if (__test_and_clear_bit(hwc->idx, cpuc->active_mask)) {
x86_pmu.disable(event);
cpuc->events[hwc->idx] = NULL;
WARN_ON_ONCE(hwc->state & PERF_HES_STOPPED);
hwc->state |= PERF_HES_STOPPED;
}
if ((flags & PERF_EF_UPDATE) && !(hwc->state & PERF_HES_UPTODATE)) {
/*
* Drain the remaining delta count out of a event
* that we are disabling:
*/
x86_perf_event_update(event);
hwc->state |= PERF_HES_UPTODATE;
}
}
static void x86_pmu_del(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
int i;
/*
* event is descheduled
*/
event->hw.flags &= ~PERF_X86_EVENT_COMMITTED;
/*
* If we're called during a txn, we don't need to do anything.
* The events never got scheduled and ->cancel_txn will truncate
* the event_list.
*
* XXX assumes any ->del() called during a TXN will only be on
* an event added during that same TXN.
*/
if (cpuc->group_flag & PERF_EVENT_TXN)
return;
/*
* Not a TXN, therefore cleanup properly.
*/
x86_pmu_stop(event, PERF_EF_UPDATE);
for (i = 0; i < cpuc->n_events; i++) {
if (event == cpuc->event_list[i])
break;
}
if (WARN_ON_ONCE(i == cpuc->n_events)) /* called ->del() without ->add() ? */
return;
/* If we have a newly added event; make sure to decrease n_added. */
if (i >= cpuc->n_events - cpuc->n_added)
--cpuc->n_added;
if (x86_pmu.put_event_constraints)
x86_pmu.put_event_constraints(cpuc, event);
/* Delete the array entry. */
while (++i < cpuc->n_events) {
cpuc->event_list[i-1] = cpuc->event_list[i];
cpuc->event_constraint[i-1] = cpuc->event_constraint[i];
}
--cpuc->n_events;
perf_event_update_userpage(event);
}
int x86_pmu_handle_irq(struct pt_regs *regs)
{
struct perf_sample_data data;
struct cpu_hw_events *cpuc;
struct perf_event *event;
int idx, handled = 0;
u64 val;
cpuc = this_cpu_ptr(&cpu_hw_events);
/*
* Some chipsets need to unmask the LVTPC in a particular spot
* inside the nmi handler. As a result, the unmasking was pushed
* into all the nmi handlers.
*
* This generic handler doesn't seem to have any issues where the
* unmasking occurs so it was left at the top.
*/
apic_write(APIC_LVTPC, APIC_DM_NMI);
for (idx = 0; idx < x86_pmu.num_counters; idx++) {
if (!test_bit(idx, cpuc->active_mask)) {
/*
* Though we deactivated the counter some cpus
* might still deliver spurious interrupts still
* in flight. Catch them:
*/
if (__test_and_clear_bit(idx, cpuc->running))
handled++;
continue;
}
event = cpuc->events[idx];
val = x86_perf_event_update(event);
if (val & (1ULL << (x86_pmu.cntval_bits - 1)))
continue;
/*
* event overflow
*/
handled++;
perf_sample_data_init(&data, 0, event->hw.last_period);
if (!x86_perf_event_set_period(event))
continue;
if (perf_event_overflow(event, &data, regs))
x86_pmu_stop(event, 0);
}
if (handled)
inc_irq_stat(apic_perf_irqs);
return handled;
}
void perf_events_lapic_init(void)
{
if (!x86_pmu.apic || !x86_pmu_initialized())
return;
/*
* Always use NMI for PMU
*/
apic_write(APIC_LVTPC, APIC_DM_NMI);
}
static int
perf_event_nmi_handler(unsigned int cmd, struct pt_regs *regs)
{
u64 start_clock;
u64 finish_clock;
int ret;
if (!atomic_read(&active_events))
return NMI_DONE;
start_clock = sched_clock();
ret = x86_pmu.handle_irq(regs);
finish_clock = sched_clock();
perf_sample_event_took(finish_clock - start_clock);
return ret;
}
NOKPROBE_SYMBOL(perf_event_nmi_handler);
struct event_constraint emptyconstraint;
struct event_constraint unconstrained;
static int
x86_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu)
{
unsigned int cpu = (long)hcpu;
struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
int i, ret = NOTIFY_OK;
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_UP_PREPARE:
for (i = 0 ; i < X86_PERF_KFREE_MAX; i++)
cpuc->kfree_on_online[i] = NULL;
if (x86_pmu.cpu_prepare)
ret = x86_pmu.cpu_prepare(cpu);
break;
case CPU_STARTING:
if (x86_pmu.cpu_starting)
x86_pmu.cpu_starting(cpu);
break;
case CPU_ONLINE:
for (i = 0 ; i < X86_PERF_KFREE_MAX; i++) {
kfree(cpuc->kfree_on_online[i]);
cpuc->kfree_on_online[i] = NULL;
}
break;
case CPU_DYING:
if (x86_pmu.cpu_dying)
x86_pmu.cpu_dying(cpu);
break;
case CPU_UP_CANCELED:
case CPU_DEAD:
if (x86_pmu.cpu_dead)
x86_pmu.cpu_dead(cpu);
break;
default:
break;
}
return ret;
}
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");
/*
* 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):
*/
pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
}
static struct attribute_group x86_pmu_format_group = {
.name = "format",
.attrs = NULL,
};
/*
* Remove all undefined events (x86_pmu.event_map(id) == 0)
* out of events_attr attributes.
*/
static void __init filter_events(struct attribute **attrs)
{
struct device_attribute *d;
struct perf_pmu_events_attr *pmu_attr;
int i, j;
for (i = 0; attrs[i]; i++) {
d = (struct device_attribute *)attrs[i];
pmu_attr = container_of(d, struct perf_pmu_events_attr, attr);
/* str trumps id */
if (pmu_attr->event_str)
continue;
if (x86_pmu.event_map(i))
continue;
for (j = i; attrs[j]; j++)
attrs[j] = attrs[j + 1];
/* Check the shifted attr. */
i--;
}
}
/* Merge two pointer arrays */
static __init struct attribute **merge_attr(struct attribute **a, struct attribute **b)
{
struct attribute **new;
int j, i;
for (j = 0; a[j]; j++)
;
for (i = 0; b[i]; i++)
j++;
j++;
new = kmalloc(sizeof(struct attribute *) * j, GFP_KERNEL);
if (!new)
return NULL;
j = 0;
for (i = 0; a[i]; i++)
new[j++] = a[i];
for (i = 0; b[i]; i++)
new[j++] = b[i];
new[j] = NULL;
return new;
}
ssize_t events_sysfs_show(struct device *dev, struct device_attribute *attr,
char *page)
{
struct perf_pmu_events_attr *pmu_attr = \
container_of(attr, struct perf_pmu_events_attr, attr);
u64 config = x86_pmu.event_map(pmu_attr->id);
/* string trumps id */
if (pmu_attr->event_str)
return sprintf(page, "%s", pmu_attr->event_str);
return x86_pmu.events_sysfs_show(page, config);
}
EVENT_ATTR(cpu-cycles, CPU_CYCLES );
EVENT_ATTR(instructions, INSTRUCTIONS );
EVENT_ATTR(cache-references, CACHE_REFERENCES );
EVENT_ATTR(cache-misses, CACHE_MISSES );
EVENT_ATTR(branch-instructions, BRANCH_INSTRUCTIONS );
EVENT_ATTR(branch-misses, BRANCH_MISSES );
EVENT_ATTR(bus-cycles, BUS_CYCLES );
EVENT_ATTR(stalled-cycles-frontend, STALLED_CYCLES_FRONTEND );
EVENT_ATTR(stalled-cycles-backend, STALLED_CYCLES_BACKEND );
EVENT_ATTR(ref-cycles, REF_CPU_CYCLES );
static struct attribute *empty_attrs;
static struct attribute *events_attr[] = {
EVENT_PTR(CPU_CYCLES),
EVENT_PTR(INSTRUCTIONS),
EVENT_PTR(CACHE_REFERENCES),
EVENT_PTR(CACHE_MISSES),
EVENT_PTR(BRANCH_INSTRUCTIONS),
EVENT_PTR(BRANCH_MISSES),
EVENT_PTR(BUS_CYCLES),
EVENT_PTR(STALLED_CYCLES_FRONTEND),
EVENT_PTR(STALLED_CYCLES_BACKEND),
EVENT_PTR(REF_CPU_CYCLES),
NULL,
};
static struct attribute_group x86_pmu_events_group = {
.name = "events",
.attrs = events_attr,
};
ssize_t x86_event_sysfs_show(char *page, u64 config, u64 event)
{
u64 umask = (config & ARCH_PERFMON_EVENTSEL_UMASK) >> 8;
u64 cmask = (config & ARCH_PERFMON_EVENTSEL_CMASK) >> 24;
bool edge = (config & ARCH_PERFMON_EVENTSEL_EDGE);
bool pc = (config & ARCH_PERFMON_EVENTSEL_PIN_CONTROL);
bool any = (config & ARCH_PERFMON_EVENTSEL_ANY);
bool inv = (config & ARCH_PERFMON_EVENTSEL_INV);
ssize_t ret;
/*
* We have whole page size to spend and just little data
* to write, so we can safely use sprintf.
*/
ret = sprintf(page, "event=0x%02llx", event);
if (umask)
ret += sprintf(page + ret, ",umask=0x%02llx", umask);
if (edge)
ret += sprintf(page + ret, ",edge");
if (pc)
ret += sprintf(page + ret, ",pc");
if (any)
ret += sprintf(page + ret, ",any");
if (inv)
ret += sprintf(page + ret, ",inv");
if (cmask)
ret += sprintf(page + ret, ",cmask=0x%02llx", cmask);
ret += sprintf(page + ret, "\n");
return ret;
}
static int __init init_hw_perf_events(void)
{
struct x86_pmu_quirk *quirk;
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:
err = -ENOTSUPP;
}
if (err != 0) {
pr_cont("no PMU driver, software events only.\n");
return 0;
}
pmu_check_apic();
/* sanity check that the hardware exists or is emulated */
if (!check_hw_exists())
return 0;
pr_cont("%s PMU driver.\n", x86_pmu.name);
x86_pmu.attr_rdpmc = 1; /* enable userspace RDPMC usage by default */
for (quirk = x86_pmu.quirks; quirk; quirk = quirk->next)
quirk->func();
if (!x86_pmu.intel_ctrl)
x86_pmu.intel_ctrl = (1 << x86_pmu.num_counters) - 1;
perf_events_lapic_init();
register_nmi_handler(NMI_LOCAL, perf_event_nmi_handler, 0, "PMI");
unconstrained = (struct event_constraint)
__EVENT_CONSTRAINT(0, (1ULL << x86_pmu.num_counters) - 1,
0, x86_pmu.num_counters, 0, 0);
x86_pmu_format_group.attrs = x86_pmu.format_attrs;
if (x86_pmu.event_attrs)
x86_pmu_events_group.attrs = x86_pmu.event_attrs;
if (!x86_pmu.events_sysfs_show)
x86_pmu_events_group.attrs = &empty_attrs;
else
filter_events(x86_pmu_events_group.attrs);
if (x86_pmu.cpu_events) {
struct attribute **tmp;
tmp = merge_attr(x86_pmu_events_group.attrs, x86_pmu.cpu_events);
if (!WARN_ON(!tmp))
x86_pmu_events_group.attrs = tmp;
}
pr_info("... version: %d\n", x86_pmu.version);
pr_info("... bit width: %d\n", x86_pmu.cntval_bits);
pr_info("... generic registers: %d\n", x86_pmu.num_counters);
pr_info("... value mask: %016Lx\n", x86_pmu.cntval_mask);
pr_info("... max period: %016Lx\n", x86_pmu.max_period);
pr_info("... fixed-purpose events: %d\n", x86_pmu.num_counters_fixed);
pr_info("... event mask: %016Lx\n", x86_pmu.intel_ctrl);
perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
perf_cpu_notifier(x86_pmu_notifier);
return 0;
}
early_initcall(init_hw_perf_events);
static inline void x86_pmu_read(struct perf_event *event)
{
x86_perf_event_update(event);
}
/*
* Start group events scheduling transaction
* Set the flag to make pmu::enable() not perform the
* schedulability test, it will be performed at commit time
*/
static void x86_pmu_start_txn(struct pmu *pmu)
{
perf_pmu_disable(pmu);
__this_cpu_or(cpu_hw_events.group_flag, PERF_EVENT_TXN);
__this_cpu_write(cpu_hw_events.n_txn, 0);
}
/*
* Stop group events scheduling transaction
* Clear the flag and pmu::enable() will perform the
* schedulability test.
*/
static void x86_pmu_cancel_txn(struct pmu *pmu)
{
__this_cpu_and(cpu_hw_events.group_flag, ~PERF_EVENT_TXN);
/*
* Truncate collected array by the number of events added in this
* transaction. See x86_pmu_add() and x86_pmu_*_txn().
*/
__this_cpu_sub(cpu_hw_events.n_added, __this_cpu_read(cpu_hw_events.n_txn));
__this_cpu_sub(cpu_hw_events.n_events, __this_cpu_read(cpu_hw_events.n_txn));
perf_pmu_enable(pmu);
}
/*
* Commit group events scheduling transaction
* Perform the group schedulability test as a whole
* Return 0 if success
*
* Does not cancel the transaction on failure; expects the caller to do this.
*/
static int x86_pmu_commit_txn(struct pmu *pmu)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
int assign[X86_PMC_IDX_MAX];
int n, ret;
n = cpuc->n_events;
if (!x86_pmu_initialized())
return -EAGAIN;
ret = x86_pmu.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->group_flag &= ~PERF_EVENT_TXN;
perf_pmu_enable(pmu);
return 0;
}
/*
* a fake_cpuc is used to validate event groups. Due to
* the extra reg logic, we need to also allocate a fake
* per_core and per_cpu structure. Otherwise, group events
* using extra reg may conflict without the kernel being
* able to catch this when the last event gets added to
* the group.
*/
static void free_fake_cpuc(struct cpu_hw_events *cpuc)
{
kfree(cpuc->shared_regs);
kfree(cpuc);
}
static struct cpu_hw_events *allocate_fake_cpuc(void)
{
struct cpu_hw_events *cpuc;
int cpu = raw_smp_processor_id();
cpuc = kzalloc(sizeof(*cpuc), GFP_KERNEL);
if (!cpuc)
return ERR_PTR(-ENOMEM);
/* only needed, if we have extra_regs */
if (x86_pmu.extra_regs) {
cpuc->shared_regs = allocate_shared_regs(cpu);
if (!cpuc->shared_regs)
goto error;
}
cpuc->is_fake = 1;
return cpuc;
error:
free_fake_cpuc(cpuc);
return ERR_PTR(-ENOMEM);
}
/*
* validate that we can schedule this event
*/
static int validate_event(struct perf_event *event)
{
struct cpu_hw_events *fake_cpuc;
struct event_constraint *c;
int ret = 0;
fake_cpuc = allocate_fake_cpuc();
if (IS_ERR(fake_cpuc))
return PTR_ERR(fake_cpuc);
c = x86_pmu.get_event_constraints(fake_cpuc, -1, event);
if (!c || !c->weight)
ret = -EINVAL;
if (x86_pmu.put_event_constraints)
x86_pmu.put_event_constraints(fake_cpuc, event);
free_fake_cpuc(fake_cpuc);
return ret;
}
/*
* 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 = -EINVAL, n;
fake_cpuc = allocate_fake_cpuc();
if (IS_ERR(fake_cpuc))
return PTR_ERR(fake_cpuc);
/*
* 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
*/
n = collect_events(fake_cpuc, leader, true);
if (n < 0)
goto out;
fake_cpuc->n_events = n;
n = collect_events(fake_cpuc, event, false);
if (n < 0)
goto out;
fake_cpuc->n_events = n;
ret = x86_pmu.schedule_events(fake_cpuc, n, NULL);
out:
free_fake_cpuc(fake_cpuc);
return ret;
}
static int x86_pmu_event_init(struct perf_event *event)
{
struct pmu *tmp;
int err;
switch (event->attr.type) {
case PERF_TYPE_RAW:
case PERF_TYPE_HARDWARE:
case PERF_TYPE_HW_CACHE:
break;
default:
return -ENOENT;
}
err = __x86_pmu_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);
else
err = validate_event(event);
event->pmu = tmp;
}
if (err) {
if (event->destroy)
event->destroy(event);
}
if (ACCESS_ONCE(x86_pmu.attr_rdpmc))
event->hw.flags |= PERF_X86_EVENT_RDPMC_ALLOWED;
return err;
}
static void refresh_pce(void *ignored)
{
if (current->mm)
load_mm_cr4(current->mm);
}
static void x86_pmu_event_mapped(struct perf_event *event)
{
if (!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED))
return;
if (atomic_inc_return(¤t->mm->context.perf_rdpmc_allowed) == 1)
on_each_cpu_mask(mm_cpumask(current->mm), refresh_pce, NULL, 1);
}
static void x86_pmu_event_unmapped(struct perf_event *event)
{
if (!current->mm)
return;
if (!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED))
return;
if (atomic_dec_and_test(¤t->mm->context.perf_rdpmc_allowed))
on_each_cpu_mask(mm_cpumask(current->mm), refresh_pce, NULL, 1);
}
static int x86_pmu_event_idx(struct perf_event *event)
{
int idx = event->hw.idx;
if (!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED))
return 0;
if (x86_pmu.num_counters_fixed && idx >= INTEL_PMC_IDX_FIXED) {
idx -= INTEL_PMC_IDX_FIXED;
idx |= 1 << 30;
}
return idx + 1;
}
static ssize_t get_attr_rdpmc(struct device *cdev,
struct device_attribute *attr,
char *buf)
{
return snprintf(buf, 40, "%d\n", x86_pmu.attr_rdpmc);
}
static ssize_t set_attr_rdpmc(struct device *cdev,
struct device_attribute *attr,
const char *buf, size_t count)
{
unsigned long val;
ssize_t ret;
ret = kstrtoul(buf, 0, &val);
if (ret)
return ret;
if (val > 2)
return -EINVAL;
if (x86_pmu.attr_rdpmc_broken)
return -ENOTSUPP;
if ((val == 2) != (x86_pmu.attr_rdpmc == 2)) {
/*
* Changing into or out of always available, aka
* perf-event-bypassing mode. This path is extremely slow,
* but only root can trigger it, so it's okay.
*/
if (val == 2)
static_key_slow_inc(&rdpmc_always_available);
else
static_key_slow_dec(&rdpmc_always_available);
on_each_cpu(refresh_pce, NULL, 1);
}
x86_pmu.attr_rdpmc = val;
return count;
}
static DEVICE_ATTR(rdpmc, S_IRUSR | S_IWUSR, get_attr_rdpmc, set_attr_rdpmc);
static struct attribute *x86_pmu_attrs[] = {
&dev_attr_rdpmc.attr,
NULL,
};
static struct attribute_group x86_pmu_attr_group = {
.attrs = x86_pmu_attrs,
};
static const struct attribute_group *x86_pmu_attr_groups[] = {
&x86_pmu_attr_group,
&x86_pmu_format_group,
&x86_pmu_events_group,
NULL,
};
static void x86_pmu_sched_task(struct perf_event_context *ctx, bool sched_in)
{
if (x86_pmu.sched_task)
x86_pmu.sched_task(ctx, sched_in);
}
void perf_check_microcode(void)
{
if (x86_pmu.check_microcode)
x86_pmu.check_microcode();
}
EXPORT_SYMBOL_GPL(perf_check_microcode);
static struct pmu pmu = {
.pmu_enable = x86_pmu_enable,
.pmu_disable = x86_pmu_disable,
.attr_groups = x86_pmu_attr_groups,
.event_init = x86_pmu_event_init,
.event_mapped = x86_pmu_event_mapped,
.event_unmapped = x86_pmu_event_unmapped,
.add = x86_pmu_add,
.del = x86_pmu_del,
.start = x86_pmu_start,
.stop = x86_pmu_stop,
.read = x86_pmu_read,
.start_txn = x86_pmu_start_txn,
.cancel_txn = x86_pmu_cancel_txn,
.commit_txn = x86_pmu_commit_txn,
.event_idx = x86_pmu_event_idx,
.sched_task = x86_pmu_sched_task,
.task_ctx_size = sizeof(struct x86_perf_task_context),
};
void arch_perf_update_userpage(struct perf_event *event,
struct perf_event_mmap_page *userpg, u64 now)
{
struct cyc2ns_data *data;
userpg->cap_user_time = 0;
userpg->cap_user_time_zero = 0;
userpg->cap_user_rdpmc =
!!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED);
userpg->pmc_width = x86_pmu.cntval_bits;
if (!sched_clock_stable())
return;
data = cyc2ns_read_begin();
/*
* Internal timekeeping for enabled/running/stopped times
* is always in the local_clock domain.
*/
userpg->cap_user_time = 1;
userpg->time_mult = data->cyc2ns_mul;
userpg->time_shift = data->cyc2ns_shift;
userpg->time_offset = data->cyc2ns_offset - now;
/*
* cap_user_time_zero doesn't make sense when we're using a different
* time base for the records.
*/
if (event->clock == &local_clock) {
userpg->cap_user_time_zero = 1;
userpg->time_zero = data->cyc2ns_offset;
}
cyc2ns_read_end(data);
}
/*
* callchain support
*/
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;
perf_callchain_store(entry, addr);
}
static const struct stacktrace_ops backtrace_ops = {
.stack = backtrace_stack,
.address = backtrace_address,
.walk_stack = print_context_stack_bp,
};
void
perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs)
{
if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
/* TODO: We don't support guest os callchain now */
return;
}
perf_callchain_store(entry, regs->ip);
dump_trace(NULL, regs, NULL, 0, &backtrace_ops, entry);
}
static inline int
valid_user_frame(const void __user *fp, unsigned long size)
{
return (__range_not_ok(fp, size, TASK_SIZE) == 0);
}
static unsigned long get_segment_base(unsigned int segment)
{
struct desc_struct *desc;
int idx = segment >> 3;
if ((segment & SEGMENT_TI_MASK) == SEGMENT_LDT) {
if (idx > LDT_ENTRIES)
return 0;
if (idx > current->active_mm->context.size)
return 0;
desc = current->active_mm->context.ldt;
} else {
if (idx > GDT_ENTRIES)
return 0;
desc = raw_cpu_ptr(gdt_page.gdt);
}
return get_desc_base(desc + idx);
}
#ifdef CONFIG_COMPAT
#include <asm/compat.h>
static inline int
perf_callchain_user32(struct pt_regs *regs, struct perf_callchain_entry *entry)
{
/* 32-bit process in 64-bit kernel. */
unsigned long ss_base, cs_base;
struct stack_frame_ia32 frame;
const void __user *fp;
if (!test_thread_flag(TIF_IA32))
return 0;
cs_base = get_segment_base(regs->cs);
ss_base = get_segment_base(regs->ss);
fp = compat_ptr(ss_base + regs->bp);
while (entry->nr < PERF_MAX_STACK_DEPTH) {
unsigned long bytes;
frame.next_frame = 0;
frame.return_address = 0;
bytes = copy_from_user_nmi(&frame, fp, sizeof(frame));
if (bytes != 0)
break;
if (!valid_user_frame(fp, sizeof(frame)))
break;
perf_callchain_store(entry, cs_base + frame.return_address);
fp = compat_ptr(ss_base + frame.next_frame);
}
return 1;
}
#else
static inline int
perf_callchain_user32(struct pt_regs *regs, struct perf_callchain_entry *entry)
{
return 0;
}
#endif
void
perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
{
struct stack_frame frame;
const void __user *fp;
if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
/* TODO: We don't support guest os callchain now */
return;
}
/*
* We don't know what to do with VM86 stacks.. ignore them for now.
*/
if (regs->flags & (X86_VM_MASK | PERF_EFLAGS_VM))
return;
fp = (void __user *)regs->bp;
perf_callchain_store(entry, regs->ip);
if (!current->mm)
return;
if (perf_callchain_user32(regs, entry))
return;
while (entry->nr < PERF_MAX_STACK_DEPTH) {
unsigned long bytes;
frame.next_frame = NULL;
frame.return_address = 0;
bytes = copy_from_user_nmi(&frame, fp, sizeof(frame));
if (bytes != 0)
break;
if (!valid_user_frame(fp, sizeof(frame)))
break;
perf_callchain_store(entry, frame.return_address);
fp = frame.next_frame;
}
}
/*
* Deal with code segment offsets for the various execution modes:
*
* VM86 - the good olde 16 bit days, where the linear address is
* 20 bits and we use regs->ip + 0x10 * regs->cs.
*
* IA32 - Where we need to look at GDT/LDT segment descriptor tables
* to figure out what the 32bit base address is.
*
* X32 - has TIF_X32 set, but is running in x86_64
*
* X86_64 - CS,DS,SS,ES are all zero based.
*/
static unsigned long code_segment_base(struct pt_regs *regs)
{
/*
* For IA32 we look at the GDT/LDT segment base to convert the
* effective IP to a linear address.
*/
#ifdef CONFIG_X86_32
/*
* If we are in VM86 mode, add the segment offset to convert to a
* linear address.
*/
if (regs->flags & X86_VM_MASK)
return 0x10 * regs->cs;
if (user_mode(regs) && regs->cs != __USER_CS)
return get_segment_base(regs->cs);
#else
if (user_mode(regs) && !user_64bit_mode(regs) &&
regs->cs != __USER32_CS)
return get_segment_base(regs->cs);
#endif
return 0;
}
unsigned long perf_instruction_pointer(struct pt_regs *regs)
{
if (perf_guest_cbs && perf_guest_cbs->is_in_guest())
return perf_guest_cbs->get_guest_ip();
return regs->ip + code_segment_base(regs);
}
unsigned long perf_misc_flags(struct pt_regs *regs)
{
int misc = 0;
if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
if (perf_guest_cbs->is_user_mode())
misc |= PERF_RECORD_MISC_GUEST_USER;
else
misc |= PERF_RECORD_MISC_GUEST_KERNEL;
} else {
if (user_mode(regs))
misc |= PERF_RECORD_MISC_USER;
else
misc |= PERF_RECORD_MISC_KERNEL;
}
if (regs->flags & PERF_EFLAGS_EXACT)
misc |= PERF_RECORD_MISC_EXACT_IP;
return misc;
}
void perf_get_x86_pmu_capability(struct x86_pmu_capability *cap)
{
cap->version = x86_pmu.version;
cap->num_counters_gp = x86_pmu.num_counters;
cap->num_counters_fixed = x86_pmu.num_counters_fixed;
cap->bit_width_gp = x86_pmu.cntval_bits;
cap->bit_width_fixed = x86_pmu.cntval_bits;
cap->events_mask = (unsigned int)x86_pmu.events_maskl;
cap->events_mask_len = x86_pmu.events_mask_len;
}
EXPORT_SYMBOL_GPL(perf_get_x86_pmu_capability);