original development tree for Linux kernel GTP module; now long in mainline.
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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/slab.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>
#include <asm/compat.h>
#if 0
#undef wrmsrl
#define wrmsrl(msr, val) \
do { \
trace_printk("wrmsrl(%lx, %lx)\n", (unsigned long)(msr),\
(unsigned long)(val)); \
native_write_msr((msr), (u32)((u64)(val)), \
(u32)((u64)(val) >> 32)); \
} while (0)
#endif
/*
* 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;
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);
memcpy(to, map+offset, size);
kunmap_atomic(map);
put_page(page);
len += size;
to += size;
addr += size;
} while (len < n);
return len;
}
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];
};
#define MAX_LBR_ENTRIES 16
struct cpu_hw_events {
/*
* Generic x86 PMC bits
*/
struct perf_event *events[X86_PMC_IDX_MAX]; /* in counter order */
unsigned long active_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
unsigned long running[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
int enabled;
int n_events;
int n_added;
int n_txn;
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 */
unsigned int group_flag;
/*
* Intel DebugStore bits
*/
struct debug_store *ds;
u64 pebs_enabled;
/*
* Intel LBR bits
*/
int lbr_users;
void *lbr_context;
struct perf_branch_stack lbr_stack;
struct perf_branch_entry lbr_entries[MAX_LBR_ENTRIES];
/*
* AMD specific bits
*/
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))
/*
* Constraint on the Event code.
*/
#define INTEL_EVENT_CONSTRAINT(c, n) \
EVENT_CONSTRAINT(c, n, ARCH_PERFMON_EVENTSEL_EVENT)
/*
* Constraint on the Event code + UMask + fixed-mask
*
* filter mask to validate fixed counter events.
* the following filters disqualify for fixed counters:
* - inv
* - edge
* - cnt-mask
* The other filters are supported by fixed counters.
* The any-thread option is supported starting with v3.
*/
#define FIXED_EVENT_CONSTRAINT(c, n) \
EVENT_CONSTRAINT(c, (1ULL << (32+n)), X86_RAW_EVENT_MASK)
/*
* Constraint on the Event code + UMask
*/
#define PEBS_EVENT_CONSTRAINT(c, n) \
EVENT_CONSTRAINT(c, n, INTEL_ARCH_EVENT_MASK)
#define EVENT_CONSTRAINT_END \
EVENT_CONSTRAINT(0, 0, 0)
#define for_each_event_constraint(e, c) \
for ((e) = (c); (e)->weight; (e)++)
union perf_capabilities {
struct {
u64 lbr_format : 6;
u64 pebs_trap : 1;
u64 pebs_arch_reg : 1;
u64 pebs_format : 4;
u64 smm_freeze : 1;
};
u64 capabilities;
};
/*
* struct x86_pmu - generic x86 pmu
*/
struct x86_pmu {
/*
* Generic x86 PMC bits
*/
const char *name;
int version;
int (*handle_irq)(struct pt_regs *);
void (*disable_all)(void);
void (*enable_all)(int added);
void (*enable)(struct perf_event *);
void (*disable)(struct perf_event *);
int (*hw_config)(struct perf_event *event);
int (*schedule_events)(struct cpu_hw_events *cpuc, int n, int *assign);
unsigned eventsel;
unsigned perfctr;
u64 (*event_map)(int);
int max_events;
int num_counters;
int num_counters_fixed;
int cntval_bits;
u64 cntval_mask;
int apic;
u64 max_period;
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 (*quirks)(void);
int perfctr_second_write;
int (*cpu_prepare)(int cpu);
void (*cpu_starting)(int cpu);
void (*cpu_dying)(int cpu);
void (*cpu_dead)(int cpu);
/*
* Intel Arch Perfmon v2+
*/
u64 intel_ctrl;
union perf_capabilities intel_cap;
/*
* Intel DebugStore bits
*/
int bts, pebs;
int bts_active, pebs_active;
int pebs_record_size;
void (*drain_pebs)(struct pt_regs *regs);
struct event_constraint *pebs_constraints;
/*
* Intel LBR
*/
unsigned long lbr_tos, lbr_from, lbr_to; /* MSR base regs */
int lbr_nr; /* hardware stack size */
};
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.cntval_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 = local64_read(&hwc->prev_count);
rdmsrl(hwc->event_base + idx, 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;
}
static atomic_t active_events;
static DEFINE_MUTEX(pmc_reserve_mutex);
#ifdef CONFIG_X86_LOCAL_APIC
static bool reserve_pmc_hardware(void)
{
int i;
if (nmi_watchdog == NMI_LOCAL_APIC)
disable_lapic_nmi_watchdog();
for (i = 0; i < x86_pmu.num_counters; i++) {
if (!reserve_perfctr_nmi(x86_pmu.perfctr + i))
goto perfctr_fail;
}
for (i = 0; i < x86_pmu.num_counters; i++) {
if (!reserve_evntsel_nmi(x86_pmu.eventsel + i))
goto eventsel_fail;
}
return true;
eventsel_fail:
for (i--; i >= 0; i--)
release_evntsel_nmi(x86_pmu.eventsel + i);
i = x86_pmu.num_counters;
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;
}
static void release_pmc_hardware(void)
{
int i;
for (i = 0; i < x86_pmu.num_counters; 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();
}
#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_new = 0;
int ret = 0;
val = 0xabcdUL;
ret |= checking_wrmsrl(x86_pmu.perfctr, val);
ret |= rdmsrl_safe(x86_pmu.perfctr, &val_new);
if (ret || val != val_new)
return false;
return true;
}
static void reserve_ds_buffers(void);
static void release_ds_buffers(void);
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);
}
}
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;
}
static 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 (!hwc->sample_period) {
hwc->sample_period = x86_pmu.max_period;
hwc->last_period = hwc->sample_period;
local64_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;
}
if (attr->type == PERF_TYPE_RAW)
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 (!x86_pmu.bts_active)
return -EOPNOTSUPP;
/* BTS is currently only allowed for user-mode. */
if (!attr->exclude_kernel)
return -EOPNOTSUPP;
}
hwc->config |= config;
return 0;
}
static 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) {
precise++;
/* Support for IP fixup */
if (x86_pmu.lbr_nr)
precise++;
}
if (event->attr.precise_ip > precise)
return -EOPNOTSUPP;
}
/*
* 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;
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;
return x86_pmu.hw_config(event);
}
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_counters; 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);
}
}
static void x86_pmu_disable(struct pmu *pmu)
{
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(int added)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
int idx;
for (idx = 0; idx < x86_pmu.num_counters; 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 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_counters;
/*
* when fixed event counters are present,
* wmax is incremented by 1 to account
* for one more choice
*/
if (x86_pmu.num_counters_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_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 -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 void x86_pmu_start(struct perf_event *event, int flags);
static void x86_pmu_stop(struct perf_event *event, int flags);
static void x86_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, 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
* step2: reprogram moved events into 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);
}
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 inline void __x86_pmu_enable_event(struct hw_perf_event *hwc,
u64 enable_mask)
{
wrmsrl(hwc->config_base + hwc->idx, hwc->config | enable_mask);
}
static inline void x86_pmu_disable_event(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
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 = local64_read(&hwc->period_left);
s64 period = hwc->sample_period;
int 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;
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;
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 + idx, (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 + idx,
(u64)(-left) & x86_pmu.cntval_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,
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 = &__get_cpu_var(cpu_hw_events);
struct hw_perf_event *hwc;
int assign[X86_PMC_IDX_MAX];
int n, n0, ret;
hwc = &event->hw;
perf_pmu_disable(event->pmu);
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 peformed
* 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:
cpuc->n_events = n;
cpuc->n_added += n - n0;
cpuc->n_txn += n - n0;
ret = 0;
out:
perf_pmu_enable(event->pmu);
return ret;
}
static void x86_pmu_start(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(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;
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);
rdmsrl(MSR_IA32_PEBS_ENABLE, pebs);
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: pebs: %016llx\n", cpu, pebs);
}
pr_info("CPU#%d: active: %016llx\n", cpu, *(u64 *)cpuc->active_mask);
for (idx = 0; idx < x86_pmu.num_counters; 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_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);
}
static void x86_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;
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 = &__get_cpu_var(cpu_hw_events);
int i;
/*
* 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.
*/
if (cpuc->group_flag & PERF_EVENT_TXN)
return;
x86_pmu_stop(event, PERF_EF_UPDATE);
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;
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_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++;
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, 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);
}
struct pmu_nmi_state {
unsigned int marked;
int handled;
};
static DEFINE_PER_CPU(struct pmu_nmi_state, pmu_nmi);
static int __kprobes
perf_event_nmi_handler(struct notifier_block *self,
unsigned long cmd, void *__args)
{
struct die_args *args = __args;
unsigned int this_nmi;
int handled;
if (!atomic_read(&active_events))
return NOTIFY_DONE;
switch (cmd) {
case DIE_NMI:
case DIE_NMI_IPI:
break;
case DIE_NMIUNKNOWN:
this_nmi = percpu_read(irq_stat.__nmi_count);
if (this_nmi != __get_cpu_var(pmu_nmi).marked)
/* let the kernel handle the unknown nmi */
return NOTIFY_DONE;
/*
* This one is a PMU back-to-back nmi. Two events
* trigger 'simultaneously' raising two back-to-back
* NMIs. If the first NMI handles both, the latter
* will be empty and daze the CPU. So, we drop it to
* avoid false-positive 'unknown nmi' messages.
*/
return NOTIFY_STOP;
default:
return NOTIFY_DONE;
}
apic_write(APIC_LVTPC, APIC_DM_NMI);
handled = x86_pmu.handle_irq(args->regs);
if (!handled)
return NOTIFY_DONE;
this_nmi = percpu_read(irq_stat.__nmi_count);
if ((handled > 1) ||
/* the next nmi could be a back-to-back nmi */
((__get_cpu_var(pmu_nmi).marked == this_nmi) &&
(__get_cpu_var(pmu_nmi).handled > 1))) {
/*
* We could have two subsequent back-to-back nmis: The
* first handles more than one counter, the 2nd
* handles only one counter and the 3rd handles no
* counter.
*
* This is the 2nd nmi because the previous was
* handling more than one counter. We will mark the
* next (3rd) and then drop it if unhandled.
*/
__get_cpu_var(pmu_nmi).marked = this_nmi + 1;
__get_cpu_var(pmu_nmi).handled = handled;
}
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;
}
#include "perf_event_amd.c"
#include "perf_event_p6.c"
#include "perf_event_p4.c"
#include "perf_event_intel_lbr.c"
#include "perf_event_intel_ds.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;
int ret = NOTIFY_OK;
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_UP_PREPARE:
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_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");
}
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();
/* sanity check that the hardware exists or is emulated */
if (!check_hw_exists()) {
pr_cont("Broken PMU hardware detected, software events only.\n");
return;
}
pr_cont("%s PMU driver.\n", x86_pmu.name);
if (x86_pmu.quirks)
x86_pmu.quirks();
if (x86_pmu.num_counters > X86_PMC_MAX_GENERIC) {
WARN(1, KERN_ERR "hw perf events %d > max(%d), clipping!",
x86_pmu.num_counters, X86_PMC_MAX_GENERIC);
x86_pmu.num_counters = X86_PMC_MAX_GENERIC;
}
x86_pmu.intel_ctrl = (1 << x86_pmu.num_counters) - 1;
if (x86_pmu.num_counters_fixed > X86_PMC_MAX_FIXED) {
WARN(1, KERN_ERR "hw perf events fixed %d > max(%d), clipping!",
x86_pmu.num_counters_fixed, X86_PMC_MAX_FIXED);
x86_pmu.num_counters_fixed = X86_PMC_MAX_FIXED;
}
x86_pmu.intel_ctrl |=
((1LL << x86_pmu.num_counters_fixed)-1) << X86_PMC_IDX_FIXED;
perf_events_lapic_init();
register_die_notifier(&perf_event_nmi_notifier);
unconstrained = (struct event_constraint)
__EVENT_CONSTRAINT(0, (1ULL << x86_pmu.num_counters) - 1,
0, x86_pmu.num_counters);
if (x86_pmu.event_constraints) {
for_each_event_constraint(c, x86_pmu.event_constraints) {
if (c->cmask != X86_RAW_EVENT_MASK)
continue;
c->idxmsk64 |= (1ULL << x86_pmu.num_counters) - 1;
c->weight += x86_pmu.num_counters;
}
}
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);
perf_cpu_notifier(x86_pmu_notifier);
}
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)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
perf_pmu_disable(pmu);
cpuc->group_flag |= PERF_EVENT_TXN;
cpuc->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)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
cpuc->group_flag &= ~PERF_EVENT_TXN;
/*
* Truncate the collected events.
*/
cpuc->n_added -= cpuc->n_txn;
cpuc->n_events -= cpuc->n_txn;
perf_pmu_enable(pmu);
}
/*
* Commit group events scheduling transaction
* Perform the group schedulability test as a whole
* Return 0 if success
*/
static int x86_pmu_commit_txn(struct pmu *pmu)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(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;
}
/*
* 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 = kmalloc(sizeof(*fake_cpuc), GFP_KERNEL | __GFP_ZERO);
if (!fake_cpuc)
return -ENOMEM;
c = x86_pmu.get_event_constraints(fake_cpuc, event);
if (!c || !c->weight)
ret = -ENOSPC;
if (x86_pmu.put_event_constraints)
x86_pmu.put_event_constraints(fake_cpuc, event);
kfree(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, 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_pmu.schedule_events(fake_cpuc, n, NULL);
out_free:
kfree(fake_cpuc);
out:
return ret;
}
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);
}
return err;
}
static struct pmu pmu = {
.pmu_enable = x86_pmu_enable,
.pmu_disable = x86_pmu_disable,
.event_init = x86_pmu_event_init,
.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,
};
/*
* callchain support
*/
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;
perf_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,
};
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, regs->bp, &backtrace_ops, entry);
}
#ifdef CONFIG_COMPAT
static inline int
perf_callchain_user32(struct pt_regs *regs, struct perf_callchain_entry *entry)
{
/* 32-bit process in 64-bit kernel. */
struct stack_frame_ia32 frame;
const void __user *fp;
if (!test_thread_flag(TIF_IA32))
return 0;
fp = compat_ptr(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 != sizeof(frame))
break;
if (fp < compat_ptr(regs->sp))
break;
perf_callchain_store(entry, frame.return_address);
fp = compat_ptr(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;
}
fp = (void __user *)regs->bp;
perf_callchain_store(entry, regs->ip);
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 != sizeof(frame))
break;
if ((unsigned long)fp < regs->sp)
break;
perf_callchain_store(entry, frame.return_address);
fp = frame.next_frame;
}
}
unsigned long perf_instruction_pointer(struct pt_regs *regs)
{
unsigned long ip;
if (perf_guest_cbs && perf_guest_cbs->is_in_guest())
ip = perf_guest_cbs->get_guest_ip();
else
ip = instruction_pointer(regs);
return ip;
}
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;
}