- 根目录:
- arch
- alpha
- kernel
- perf_event.c
/*
* Hardware performance events for the Alpha.
*
* We implement HW counts on the EV67 and subsequent CPUs only.
*
* (C) 2010 Michael J. Cree
*
* Somewhat based on the Sparc code, and to a lesser extent the PowerPC and
* ARM code, which are copyright by their respective authors.
*/
#include <linux/perf_event.h>
#include <linux/kprobes.h>
#include <linux/kernel.h>
#include <linux/kdebug.h>
#include <linux/mutex.h>
#include <linux/init.h>
#include <asm/hwrpb.h>
#include <linux/atomic.h>
#include <asm/irq.h>
#include <asm/irq_regs.h>
#include <asm/pal.h>
#include <asm/wrperfmon.h>
#include <asm/hw_irq.h>
/* The maximum number of PMCs on any Alpha CPU whatsoever. */
#define MAX_HWEVENTS 3
#define PMC_NO_INDEX -1
/* For tracking PMCs and the hw events they monitor on each CPU. */
struct cpu_hw_events {
int enabled;
/* Number of events scheduled; also number entries valid in arrays below. */
int n_events;
/* Number events added since last hw_perf_disable(). */
int n_added;
/* Events currently scheduled. */
struct perf_event *event[MAX_HWEVENTS];
/* Event type of each scheduled event. */
unsigned long evtype[MAX_HWEVENTS];
/* Current index of each scheduled event; if not yet determined
* contains PMC_NO_INDEX.
*/
int current_idx[MAX_HWEVENTS];
/* The active PMCs' config for easy use with wrperfmon(). */
unsigned long config;
/* The active counters' indices for easy use with wrperfmon(). */
unsigned long idx_mask;
};
DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events);
/*
* A structure to hold the description of the PMCs available on a particular
* type of Alpha CPU.
*/
struct alpha_pmu_t {
/* Mapping of the perf system hw event types to indigenous event types */
const int *event_map;
/* The number of entries in the event_map */
int max_events;
/* The number of PMCs on this Alpha */
int num_pmcs;
/*
* All PMC counters reside in the IBOX register PCTR. This is the
* LSB of the counter.
*/
int pmc_count_shift[MAX_HWEVENTS];
/*
* The mask that isolates the PMC bits when the LSB of the counter
* is shifted to bit 0.
*/
unsigned long pmc_count_mask[MAX_HWEVENTS];
/* The maximum period the PMC can count. */
unsigned long pmc_max_period[MAX_HWEVENTS];
/*
* The maximum value that may be written to the counter due to
* hardware restrictions is pmc_max_period - pmc_left.
*/
long pmc_left[3];
/* Subroutine for allocation of PMCs. Enforces constraints. */
int (*check_constraints)(struct perf_event **, unsigned long *, int);
/* Subroutine for checking validity of a raw event for this PMU. */
int (*raw_event_valid)(u64 config);
};
/*
* The Alpha CPU PMU description currently in operation. This is set during
* the boot process to the specific CPU of the machine.
*/
static const struct alpha_pmu_t *alpha_pmu;
#define HW_OP_UNSUPPORTED -1
/*
* The hardware description of the EV67, EV68, EV69, EV7 and EV79 PMUs
* follow. Since they are identical we refer to them collectively as the
* EV67 henceforth.
*/
/*
* EV67 PMC event types
*
* There is no one-to-one mapping of the possible hw event types to the
* actual codes that are used to program the PMCs hence we introduce our
* own hw event type identifiers.
*/
enum ev67_pmc_event_type {
EV67_CYCLES = 1,
EV67_INSTRUCTIONS,
EV67_BCACHEMISS,
EV67_MBOXREPLAY,
EV67_LAST_ET
};
#define EV67_NUM_EVENT_TYPES (EV67_LAST_ET-EV67_CYCLES)
/* Mapping of the hw event types to the perf tool interface */
static const int ev67_perfmon_event_map[] = {
[PERF_COUNT_HW_CPU_CYCLES] = EV67_CYCLES,
[PERF_COUNT_HW_INSTRUCTIONS] = EV67_INSTRUCTIONS,
[PERF_COUNT_HW_CACHE_REFERENCES] = HW_OP_UNSUPPORTED,
[PERF_COUNT_HW_CACHE_MISSES] = EV67_BCACHEMISS,
};
struct ev67_mapping_t {
int config;
int idx;
};
/*
* The mapping used for one event only - these must be in same order as enum
* ev67_pmc_event_type definition.
*/
static const struct ev67_mapping_t ev67_mapping[] = {
{EV67_PCTR_INSTR_CYCLES, 1}, /* EV67_CYCLES, */
{EV67_PCTR_INSTR_CYCLES, 0}, /* EV67_INSTRUCTIONS */
{EV67_PCTR_INSTR_BCACHEMISS, 1}, /* EV67_BCACHEMISS */
{EV67_PCTR_CYCLES_MBOX, 1} /* EV67_MBOXREPLAY */
};
/*
* Check that a group of events can be simultaneously scheduled on to the
* EV67 PMU. Also allocate counter indices and config.
*/
static int ev67_check_constraints(struct perf_event **event,
unsigned long *evtype, int n_ev)
{
int idx0;
unsigned long config;
idx0 = ev67_mapping[evtype[0]-1].idx;
config = ev67_mapping[evtype[0]-1].config;
if (n_ev == 1)
goto success;
BUG_ON(n_ev != 2);
if (evtype[0] == EV67_MBOXREPLAY || evtype[1] == EV67_MBOXREPLAY) {
/* MBOX replay traps must be on PMC 1 */
idx0 = (evtype[0] == EV67_MBOXREPLAY) ? 1 : 0;
/* Only cycles can accompany MBOX replay traps */
if (evtype[idx0] == EV67_CYCLES) {
config = EV67_PCTR_CYCLES_MBOX;
goto success;
}
}
if (evtype[0] == EV67_BCACHEMISS || evtype[1] == EV67_BCACHEMISS) {
/* Bcache misses must be on PMC 1 */
idx0 = (evtype[0] == EV67_BCACHEMISS) ? 1 : 0;
/* Only instructions can accompany Bcache misses */
if (evtype[idx0] == EV67_INSTRUCTIONS) {
config = EV67_PCTR_INSTR_BCACHEMISS;
goto success;
}
}
if (evtype[0] == EV67_INSTRUCTIONS || evtype[1] == EV67_INSTRUCTIONS) {
/* Instructions must be on PMC 0 */
idx0 = (evtype[0] == EV67_INSTRUCTIONS) ? 0 : 1;
/* By this point only cycles can accompany instructions */
if (evtype[idx0^1] == EV67_CYCLES) {
config = EV67_PCTR_INSTR_CYCLES;
goto success;
}
}
/* Otherwise, darn it, there is a conflict. */
return -1;
success:
event[0]->hw.idx = idx0;
event[0]->hw.config_base = config;
if (n_ev == 2) {
event[1]->hw.idx = idx0 ^ 1;
event[1]->hw.config_base = config;
}
return 0;
}
static int ev67_raw_event_valid(u64 config)
{
return config >= EV67_CYCLES && config < EV67_LAST_ET;
};
static const struct alpha_pmu_t ev67_pmu = {
.event_map = ev67_perfmon_event_map,
.max_events = ARRAY_SIZE(ev67_perfmon_event_map),
.num_pmcs = 2,
.pmc_count_shift = {EV67_PCTR_0_COUNT_SHIFT, EV67_PCTR_1_COUNT_SHIFT, 0},
.pmc_count_mask = {EV67_PCTR_0_COUNT_MASK, EV67_PCTR_1_COUNT_MASK, 0},
.pmc_max_period = {(1UL<<20) - 1, (1UL<<20) - 1, 0},
.pmc_left = {16, 4, 0},
.check_constraints = ev67_check_constraints,
.raw_event_valid = ev67_raw_event_valid,
};
/*
* Helper routines to ensure that we read/write only the correct PMC bits
* when calling the wrperfmon PALcall.
*/
static inline void alpha_write_pmc(int idx, unsigned long val)
{
val &= alpha_pmu->pmc_count_mask[idx];
val <<= alpha_pmu->pmc_count_shift[idx];
val |= (1<<idx);
wrperfmon(PERFMON_CMD_WRITE, val);
}
static inline unsigned long alpha_read_pmc(int idx)
{
unsigned long val;
val = wrperfmon(PERFMON_CMD_READ, 0);
val >>= alpha_pmu->pmc_count_shift[idx];
val &= alpha_pmu->pmc_count_mask[idx];
return val;
}
/* Set a new period to sample over */
static int alpha_perf_event_set_period(struct perf_event *event,
struct hw_perf_event *hwc, int idx)
{
long left = local64_read(&hwc->period_left);
long period = hwc->sample_period;
int ret = 0;
if (unlikely(left <= -period)) {
left = period;
local64_set(&hwc->period_left, left);
hwc->last_period = period;
ret = 1;
}
if (unlikely(left <= 0)) {
left += period;
local64_set(&hwc->period_left, left);
hwc->last_period = period;
ret = 1;
}
/*
* Hardware restrictions require that the counters must not be
* written with values that are too close to the maximum period.
*/
if (unlikely(left < alpha_pmu->pmc_left[idx]))
left = alpha_pmu->pmc_left[idx];
if (left > (long)alpha_pmu->pmc_max_period[idx])
left = alpha_pmu->pmc_max_period[idx];
local64_set(&hwc->prev_count, (unsigned long)(-left));
alpha_write_pmc(idx, (unsigned long)(-left));
perf_event_update_userpage(event);
return ret;
}
/*
* Calculates the count (the 'delta') since the last time the PMC was read.
*
* As the PMCs' full period can easily be exceeded within the perf system
* sampling period we cannot use any high order bits as a guard bit in the
* PMCs to detect overflow as is done by other architectures. The code here
* calculates the delta on the basis that there is no overflow when ovf is
* zero. The value passed via ovf by the interrupt handler corrects for
* overflow.
*
* This can be racey on rare occasions -- a call to this routine can occur
* with an overflowed counter just before the PMI service routine is called.
* The check for delta negative hopefully always rectifies this situation.
*/
static unsigned long alpha_perf_event_update(struct perf_event *event,
struct hw_perf_event *hwc, int idx, long ovf)
{
long prev_raw_count, new_raw_count;
long delta;
again:
prev_raw_count = local64_read(&hwc->prev_count);
new_raw_count = alpha_read_pmc(idx);
if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
new_raw_count) != prev_raw_count)
goto again;
delta = (new_raw_count - (prev_raw_count & alpha_pmu->pmc_count_mask[idx])) + ovf;
/* It is possible on very rare occasions that the PMC has overflowed
* but the interrupt is yet to come. Detect and fix this situation.
*/
if (unlikely(delta < 0)) {
delta += alpha_pmu->pmc_max_period[idx] + 1;
}
local64_add(delta, &event->count);
local64_sub(delta, &hwc->period_left);
return new_raw_count;
}
/*
* Collect all HW events into the array event[].
*/
static int collect_events(struct perf_event *group, int max_count,
struct perf_event *event[], unsigned long *evtype,
int *current_idx)
{
struct perf_event *pe;
int n = 0;
if (!is_software_event(group)) {
if (n >= max_count)
return -1;
event[n] = group;
evtype[n] = group->hw.event_base;
current_idx[n++] = PMC_NO_INDEX;
}
list_for_each_entry(pe, &group->sibling_list, group_entry) {
if (!is_software_event(pe) && pe->state != PERF_EVENT_STATE_OFF) {
if (n >= max_count)
return -1;
event[n] = pe;
evtype[n] = pe->hw.event_base;
current_idx[n++] = PMC_NO_INDEX;
}
}
return n;
}
/*
* Check that a group of events can be simultaneously scheduled on to the PMU.
*/
static int alpha_check_constraints(struct perf_event **events,
unsigned long *evtypes, int n_ev)
{
/* No HW events is possible from hw_perf_group_sched_in(). */
if (n_ev == 0)
return 0;
if (n_ev > alpha_pmu->num_pmcs)
return -1;
return alpha_pmu->check_constraints(events, evtypes, n_ev);
}
/*
* If new events have been scheduled then update cpuc with the new
* configuration. This may involve shifting cycle counts from one PMC to
* another.
*/
static void maybe_change_configuration(struct cpu_hw_events *cpuc)
{
int j;
if (cpuc->n_added == 0)
return;
/* Find counters that are moving to another PMC and update */
for (j = 0; j < cpuc->n_events; j++) {
struct perf_event *pe = cpuc->event[j];
if (cpuc->current_idx[j] != PMC_NO_INDEX &&
cpuc->current_idx[j] != pe->hw.idx) {
alpha_perf_event_update(pe, &pe->hw, cpuc->current_idx[j], 0);
cpuc->current_idx[j] = PMC_NO_INDEX;
}
}
/* Assign to counters all unassigned events. */
cpuc->idx_mask = 0;
for (j = 0; j < cpuc->n_events; j++) {
struct perf_event *pe = cpuc->event[j];
struct hw_perf_event *hwc = &pe->hw;
int idx = hwc->idx;
if (cpuc->current_idx[j] == PMC_NO_INDEX) {
alpha_perf_event_set_period(pe, hwc, idx);
cpuc->current_idx[j] = idx;
}
if (!(hwc->state & PERF_HES_STOPPED))
cpuc->idx_mask |= (1<<cpuc->current_idx[j]);
}
cpuc->config = cpuc->event[0]->hw.config_base;
}
/* Schedule perf HW event on to PMU.
* - this function is called from outside this module via the pmu struct
* returned from perf event initialisation.
*/
static int alpha_pmu_add(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
struct hw_perf_event *hwc = &event->hw;
int n0;
int ret;
unsigned long irq_flags;
/*
* The Sparc code has the IRQ disable first followed by the perf
* disable, however this can lead to an overflowed counter with the
* PMI disabled on rare occasions. The alpha_perf_event_update()
* routine should detect this situation by noting a negative delta,
* nevertheless we disable the PMCs first to enable a potential
* final PMI to occur before we disable interrupts.
*/
perf_pmu_disable(event->pmu);
local_irq_save(irq_flags);
/* Default to error to be returned */
ret = -EAGAIN;
/* Insert event on to PMU and if successful modify ret to valid return */
n0 = cpuc->n_events;
if (n0 < alpha_pmu->num_pmcs) {
cpuc->event[n0] = event;
cpuc->evtype[n0] = event->hw.event_base;
cpuc->current_idx[n0] = PMC_NO_INDEX;
if (!alpha_check_constraints(cpuc->event, cpuc->evtype, n0+1)) {
cpuc->n_events++;
cpuc->n_added++;
ret = 0;
}
}
hwc->state = PERF_HES_UPTODATE;
if (!(flags & PERF_EF_START))
hwc->state |= PERF_HES_STOPPED;
local_irq_restore(irq_flags);
perf_pmu_enable(event->pmu);
return ret;
}
/* Disable performance monitoring unit
* - this function is called from outside this module via the pmu struct
* returned from perf event initialisation.
*/
static void alpha_pmu_del(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
struct hw_perf_event *hwc = &event->hw;
unsigned long irq_flags;
int j;
perf_pmu_disable(event->pmu);
local_irq_save(irq_flags);
for (j = 0; j < cpuc->n_events; j++) {
if (event == cpuc->event[j]) {
int idx = cpuc->current_idx[j];
/* Shift remaining entries down into the existing
* slot.
*/
while (++j < cpuc->n_events) {
cpuc->event[j - 1] = cpuc->event[j];
cpuc->evtype[j - 1] = cpuc->evtype[j];
cpuc->current_idx[j - 1] =
cpuc->current_idx[j];
}
/* Absorb the final count and turn off the event. */
alpha_perf_event_update(event, hwc, idx, 0);
perf_event_update_userpage(event);
cpuc->idx_mask &= ~(1UL<<idx);
cpuc->n_events--;
break;
}
}
local_irq_restore(irq_flags);
perf_pmu_enable(event->pmu);
}
static void alpha_pmu_read(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
alpha_perf_event_update(event, hwc, hwc->idx, 0);
}
static void alpha_pmu_stop(struct perf_event *event, int flags)
{
struct hw_perf_event *hwc = &event->hw;
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
if (!(hwc->state & PERF_HES_STOPPED)) {
cpuc->idx_mask &= ~(1UL<<hwc->idx);
hwc->state |= PERF_HES_STOPPED;
}
if ((flags & PERF_EF_UPDATE) && !(hwc->state & PERF_HES_UPTODATE)) {
alpha_perf_event_update(event, hwc, hwc->idx, 0);
hwc->state |= PERF_HES_UPTODATE;
}
if (cpuc->enabled)
wrperfmon(PERFMON_CMD_DISABLE, (1UL<<hwc->idx));
}
static void alpha_pmu_start(struct perf_event *event, int flags)
{
struct hw_perf_event *hwc = &event->hw;
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
if (WARN_ON_ONCE(!(hwc->state & PERF_HES_STOPPED)))
return;
if (flags & PERF_EF_RELOAD) {
WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
alpha_perf_event_set_period(event, hwc, hwc->idx);
}
hwc->state = 0;
cpuc->idx_mask |= 1UL<<hwc->idx;
if (cpuc->enabled)
wrperfmon(PERFMON_CMD_ENABLE, (1UL<<hwc->idx));
}
/*
* Check that CPU performance counters are supported.
* - currently support EV67 and later CPUs.
* - actually some later revisions of the EV6 have the same PMC model as the
* EV67 but we don't do suffiently deep CPU detection to detect them.
* Bad luck to the very few people who might have one, I guess.
*/
static int supported_cpu(void)
{
struct percpu_struct *cpu;
unsigned long cputype;
/* Get cpu type from HW */
cpu = (struct percpu_struct *)((char *)hwrpb + hwrpb->processor_offset);
cputype = cpu->type & 0xffffffff;
/* Include all of EV67, EV68, EV7, EV79 and EV69 as supported. */
return (cputype >= EV67_CPU) && (cputype <= EV69_CPU);
}
static void hw_perf_event_destroy(struct perf_event *event)
{
/* Nothing to be done! */
return;
}
static int __hw_perf_event_init(struct perf_event *event)
{
struct perf_event_attr *attr = &event->attr;
struct hw_perf_event *hwc = &event->hw;
struct perf_event *evts[MAX_HWEVENTS];
unsigned long evtypes[MAX_HWEVENTS];
int idx_rubbish_bin[MAX_HWEVENTS];
int ev;
int n;
/* We only support a limited range of HARDWARE event types with one
* only programmable via a RAW event type.
*/
if (attr->type == PERF_TYPE_HARDWARE) {
if (attr->config >= alpha_pmu->max_events)
return -EINVAL;
ev = alpha_pmu->event_map[attr->config];
} else if (attr->type == PERF_TYPE_HW_CACHE) {
return -EOPNOTSUPP;
} else if (attr->type == PERF_TYPE_RAW) {
if (!alpha_pmu->raw_event_valid(attr->config))
return -EINVAL;
ev = attr->config;
} else {
return -EOPNOTSUPP;
}
if (ev < 0) {
return ev;
}
/* The EV67 does not support mode exclusion */
if (attr->exclude_kernel || attr->exclude_user
|| attr->exclude_hv || attr->exclude_idle) {
return -EPERM;
}
/*
* We place the event type in event_base here and leave calculation
* of the codes to programme the PMU for alpha_pmu_enable() because
* it is only then we will know what HW events are actually
* scheduled on to the PMU. At that point the code to programme the
* PMU is put into config_base and the PMC to use is placed into
* idx. We initialise idx (below) to PMC_NO_INDEX to indicate that
* it is yet to be determined.
*/
hwc->event_base = ev;
/* Collect events in a group together suitable for calling
* alpha_check_constraints() to verify that the group as a whole can
* be scheduled on to the PMU.
*/
n = 0;
if (event->group_leader != event) {
n = collect_events(event->group_leader,
alpha_pmu->num_pmcs - 1,
evts, evtypes, idx_rubbish_bin);
if (n < 0)
return -EINVAL;
}
evtypes[n] = hwc->event_base;
evts[n] = event;
if (alpha_check_constraints(evts, evtypes, n + 1))
return -EINVAL;
/* Indicate that PMU config and idx are yet to be determined. */
hwc->config_base = 0;
hwc->idx = PMC_NO_INDEX;
event->destroy = hw_perf_event_destroy;
/*
* Most architectures reserve the PMU for their use at this point.
* As there is no existing mechanism to arbitrate usage and there
* appears to be no other user of the Alpha PMU we just assume
* that we can just use it, hence a NO-OP here.
*
* Maybe an alpha_reserve_pmu() routine should be implemented but is
* anything else ever going to use it?
*/
if (!hwc->sample_period) {
hwc->sample_period = alpha_pmu->pmc_max_period[0];
hwc->last_period = hwc->sample_period;
local64_set(&hwc->period_left, hwc->sample_period);
}
return 0;
}
/*
* Main entry point to initialise a HW performance event.
*/
static int alpha_pmu_event_init(struct perf_event *event)
{
int err;
/* does not support taken branch sampling */
if (has_branch_stack(event))
return -EOPNOTSUPP;
switch (event->attr.type) {
case PERF_TYPE_RAW:
case PERF_TYPE_HARDWARE:
case PERF_TYPE_HW_CACHE:
break;
default:
return -ENOENT;
}
if (!alpha_pmu)
return -ENODEV;
/* Do the real initialisation work. */
err = __hw_perf_event_init(event);
return err;
}
/*
* Main entry point - enable HW performance counters.
*/
static void alpha_pmu_enable(struct pmu *pmu)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
if (cpuc->enabled)
return;
cpuc->enabled = 1;
barrier();
if (cpuc->n_events > 0) {
/* Update cpuc with information from any new scheduled events. */
maybe_change_configuration(cpuc);
/* Start counting the desired events. */
wrperfmon(PERFMON_CMD_LOGGING_OPTIONS, EV67_PCTR_MODE_AGGREGATE);
wrperfmon(PERFMON_CMD_DESIRED_EVENTS, cpuc->config);
wrperfmon(PERFMON_CMD_ENABLE, cpuc->idx_mask);
}
}
/*
* Main entry point - disable HW performance counters.
*/
static void alpha_pmu_disable(struct pmu *pmu)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
if (!cpuc->enabled)
return;
cpuc->enabled = 0;
cpuc->n_added = 0;
wrperfmon(PERFMON_CMD_DISABLE, cpuc->idx_mask);
}
static struct pmu pmu = {
.pmu_enable = alpha_pmu_enable,
.pmu_disable = alpha_pmu_disable,
.event_init = alpha_pmu_event_init,
.add = alpha_pmu_add,
.del = alpha_pmu_del,
.start = alpha_pmu_start,
.stop = alpha_pmu_stop,
.read = alpha_pmu_read,
};
/*
* Main entry point - don't know when this is called but it
* obviously dumps debug info.
*/
void perf_event_print_debug(void)
{
unsigned long flags;
unsigned long pcr;
int pcr0, pcr1;
int cpu;
if (!supported_cpu())
return;
local_irq_save(flags);
cpu = smp_processor_id();
pcr = wrperfmon(PERFMON_CMD_READ, 0);
pcr0 = (pcr >> alpha_pmu->pmc_count_shift[0]) & alpha_pmu->pmc_count_mask[0];
pcr1 = (pcr >> alpha_pmu->pmc_count_shift[1]) & alpha_pmu->pmc_count_mask[1];
pr_info("CPU#%d: PCTR0[%06x] PCTR1[%06x]\n", cpu, pcr0, pcr1);
local_irq_restore(flags);
}
/*
* Performance Monitoring Interrupt Service Routine called when a PMC
* overflows. The PMC that overflowed is passed in la_ptr.
*/
static void alpha_perf_event_irq_handler(unsigned long la_ptr,
struct pt_regs *regs)
{
struct cpu_hw_events *cpuc;
struct perf_sample_data data;
struct perf_event *event;
struct hw_perf_event *hwc;
int idx, j;
__this_cpu_inc(irq_pmi_count);
cpuc = this_cpu_ptr(&cpu_hw_events);
/* Completely counting through the PMC's period to trigger a new PMC
* overflow interrupt while in this interrupt routine is utterly
* disastrous! The EV6 and EV67 counters are sufficiently large to
* prevent this but to be really sure disable the PMCs.
*/
wrperfmon(PERFMON_CMD_DISABLE, cpuc->idx_mask);
/* la_ptr is the counter that overflowed. */
if (unlikely(la_ptr >= alpha_pmu->num_pmcs)) {
/* This should never occur! */
irq_err_count++;
pr_warning("PMI: silly index %ld\n", la_ptr);
wrperfmon(PERFMON_CMD_ENABLE, cpuc->idx_mask);
return;
}
idx = la_ptr;
for (j = 0; j < cpuc->n_events; j++) {
if (cpuc->current_idx[j] == idx)
break;
}
if (unlikely(j == cpuc->n_events)) {
/* This can occur if the event is disabled right on a PMC overflow. */
wrperfmon(PERFMON_CMD_ENABLE, cpuc->idx_mask);
return;
}
event = cpuc->event[j];
if (unlikely(!event)) {
/* This should never occur! */
irq_err_count++;
pr_warning("PMI: No event at index %d!\n", idx);
wrperfmon(PERFMON_CMD_ENABLE, cpuc->idx_mask);
return;
}
hwc = &event->hw;
alpha_perf_event_update(event, hwc, idx, alpha_pmu->pmc_max_period[idx]+1);
perf_sample_data_init(&data, 0, hwc->last_period);
if (alpha_perf_event_set_period(event, hwc, idx)) {
if (perf_event_overflow(event, &data, regs)) {
/* Interrupts coming too quickly; "throttle" the
* counter, i.e., disable it for a little while.
*/
alpha_pmu_stop(event, 0);
}
}
wrperfmon(PERFMON_CMD_ENABLE, cpuc->idx_mask);
return;
}
/*
* Init call to initialise performance events at kernel startup.
*/
int __init init_hw_perf_events(void)
{
pr_info("Performance events: ");
if (!supported_cpu()) {
pr_cont("No support for your CPU.\n");
return 0;
}
pr_cont("Supported CPU type!\n");
/* Override performance counter IRQ vector */
perf_irq = alpha_perf_event_irq_handler;
/* And set up PMU specification */
alpha_pmu = &ev67_pmu;
perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
return 0;
}
early_initcall(init_hw_perf_events);