Linux-2.6.33.2/arch/powerpc/kernel/perf_event.c
/*
* Performance event support - powerpc architecture code
*
* Copyright 2008-2009 Paul Mackerras, IBM Corporation.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/perf_event.h>
#include <linux/percpu.h>
#include <linux/hardirq.h>
#include <asm/reg.h>
#include <asm/pmc.h>
#include <asm/machdep.h>
#include <asm/firmware.h>
#include <asm/ptrace.h>
struct cpu_hw_events {
int n_events;
int n_percpu;
int disabled;
int n_added;
int n_limited;
u8 pmcs_enabled;
struct perf_event *event[MAX_HWEVENTS];
u64 events[MAX_HWEVENTS];
unsigned int flags[MAX_HWEVENTS];
unsigned long mmcr[3];
struct perf_event *limited_counter[MAX_LIMITED_HWCOUNTERS];
u8 limited_hwidx[MAX_LIMITED_HWCOUNTERS];
u64 alternatives[MAX_HWEVENTS][MAX_EVENT_ALTERNATIVES];
unsigned long amasks[MAX_HWEVENTS][MAX_EVENT_ALTERNATIVES];
unsigned long avalues[MAX_HWEVENTS][MAX_EVENT_ALTERNATIVES];
};
DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events);
struct power_pmu *ppmu;
/*
* Normally, to ignore kernel events we set the FCS (freeze counters
* in supervisor mode) bit in MMCR0, but if the kernel runs with the
* hypervisor bit set in the MSR, or if we are running on a processor
* where the hypervisor bit is forced to 1 (as on Apple G5 processors),
* then we need to use the FCHV bit to ignore kernel events.
*/
static unsigned int freeze_events_kernel = MMCR0_FCS;
/*
* 32-bit doesn't have MMCRA but does have an MMCR2,
* and a few other names are different.
*/
#ifdef CONFIG_PPC32
#define MMCR0_FCHV 0
#define MMCR0_PMCjCE MMCR0_PMCnCE
#define SPRN_MMCRA SPRN_MMCR2
#define MMCRA_SAMPLE_ENABLE 0
static inline unsigned long perf_ip_adjust(struct pt_regs *regs)
{
return 0;
}
static inline void perf_get_data_addr(struct pt_regs *regs, u64 *addrp) { }
static inline u32 perf_get_misc_flags(struct pt_regs *regs)
{
return 0;
}
static inline void perf_read_regs(struct pt_regs *regs) { }
static inline int perf_intr_is_nmi(struct pt_regs *regs)
{
return 0;
}
#endif /* CONFIG_PPC32 */
/*
* Things that are specific to 64-bit implementations.
*/
#ifdef CONFIG_PPC64
static inline unsigned long perf_ip_adjust(struct pt_regs *regs)
{
unsigned long mmcra = regs->dsisr;
if ((mmcra & MMCRA_SAMPLE_ENABLE) && !(ppmu->flags & PPMU_ALT_SIPR)) {
unsigned long slot = (mmcra & MMCRA_SLOT) >> MMCRA_SLOT_SHIFT;
if (slot > 1)
return 4 * (slot - 1);
}
return 0;
}
/*
* The user wants a data address recorded.
* If we're not doing instruction sampling, give them the SDAR
* (sampled data address). If we are doing instruction sampling, then
* only give them the SDAR if it corresponds to the instruction
* pointed to by SIAR; this is indicated by the [POWER6_]MMCRA_SDSYNC
* bit in MMCRA.
*/
static inline void perf_get_data_addr(struct pt_regs *regs, u64 *addrp)
{
unsigned long mmcra = regs->dsisr;
unsigned long sdsync = (ppmu->flags & PPMU_ALT_SIPR) ?
POWER6_MMCRA_SDSYNC : MMCRA_SDSYNC;
if (!(mmcra & MMCRA_SAMPLE_ENABLE) || (mmcra & sdsync))
*addrp = mfspr(SPRN_SDAR);
}
static inline u32 perf_get_misc_flags(struct pt_regs *regs)
{
unsigned long mmcra = regs->dsisr;
unsigned long sihv = MMCRA_SIHV;
unsigned long sipr = MMCRA_SIPR;
if (TRAP(regs) != 0xf00)
return 0; /* not a PMU interrupt */
if (ppmu->flags & PPMU_ALT_SIPR) {
sihv = POWER6_MMCRA_SIHV;
sipr = POWER6_MMCRA_SIPR;
}
/* PR has priority over HV, so order below is important */
if (mmcra & sipr)
return PERF_RECORD_MISC_USER;
if ((mmcra & sihv) && (freeze_events_kernel != MMCR0_FCHV))
return PERF_RECORD_MISC_HYPERVISOR;
return PERF_RECORD_MISC_KERNEL;
}
/*
* Overload regs->dsisr to store MMCRA so we only need to read it once
* on each interrupt.
*/
static inline void perf_read_regs(struct pt_regs *regs)
{
regs->dsisr = mfspr(SPRN_MMCRA);
}
/*
* If interrupts were soft-disabled when a PMU interrupt occurs, treat
* it as an NMI.
*/
static inline int perf_intr_is_nmi(struct pt_regs *regs)
{
return !regs->softe;
}
#endif /* CONFIG_PPC64 */
static void perf_event_interrupt(struct pt_regs *regs);
void perf_event_print_debug(void)
{
}
/*
* Read one performance monitor counter (PMC).
*/
static unsigned long read_pmc(int idx)
{
unsigned long val;
switch (idx) {
case 1:
val = mfspr(SPRN_PMC1);
break;
case 2:
val = mfspr(SPRN_PMC2);
break;
case 3:
val = mfspr(SPRN_PMC3);
break;
case 4:
val = mfspr(SPRN_PMC4);
break;
case 5:
val = mfspr(SPRN_PMC5);
break;
case 6:
val = mfspr(SPRN_PMC6);
break;
#ifdef CONFIG_PPC64
case 7:
val = mfspr(SPRN_PMC7);
break;
case 8:
val = mfspr(SPRN_PMC8);
break;
#endif /* CONFIG_PPC64 */
default:
printk(KERN_ERR "oops trying to read PMC%d\n", idx);
val = 0;
}
return val;
}
/*
* Write one PMC.
*/
static void write_pmc(int idx, unsigned long val)
{
switch (idx) {
case 1:
mtspr(SPRN_PMC1, val);
break;
case 2:
mtspr(SPRN_PMC2, val);
break;
case 3:
mtspr(SPRN_PMC3, val);
break;
case 4:
mtspr(SPRN_PMC4, val);
break;
case 5:
mtspr(SPRN_PMC5, val);
break;
case 6:
mtspr(SPRN_PMC6, val);
break;
#ifdef CONFIG_PPC64
case 7:
mtspr(SPRN_PMC7, val);
break;
case 8:
mtspr(SPRN_PMC8, val);
break;
#endif /* CONFIG_PPC64 */
default:
printk(KERN_ERR "oops trying to write PMC%d\n", idx);
}
}
/*
* Check if a set of events can all go on the PMU at once.
* If they can't, this will look at alternative codes for the events
* and see if any combination of alternative codes is feasible.
* The feasible set is returned in event_id[].
*/
static int power_check_constraints(struct cpu_hw_events *cpuhw,
u64 event_id[], unsigned int cflags[],
int n_ev)
{
unsigned long mask, value, nv;
unsigned long smasks[MAX_HWEVENTS], svalues[MAX_HWEVENTS];
int n_alt[MAX_HWEVENTS], choice[MAX_HWEVENTS];
int i, j;
unsigned long addf = ppmu->add_fields;
unsigned long tadd = ppmu->test_adder;
if (n_ev > ppmu->n_counter)
return -1;
/* First see if the events will go on as-is */
for (i = 0; i < n_ev; ++i) {
if ((cflags[i] & PPMU_LIMITED_PMC_REQD)
&& !ppmu->limited_pmc_event(event_id[i])) {
ppmu->get_alternatives(event_id[i], cflags[i],
cpuhw->alternatives[i]);
event_id[i] = cpuhw->alternatives[i][0];
}
if (ppmu->get_constraint(event_id[i], &cpuhw->amasks[i][0],
&cpuhw->avalues[i][0]))
return -1;
}
value = mask = 0;
for (i = 0; i < n_ev; ++i) {
nv = (value | cpuhw->avalues[i][0]) +
(value & cpuhw->avalues[i][0] & addf);
if ((((nv + tadd) ^ value) & mask) != 0 ||
(((nv + tadd) ^ cpuhw->avalues[i][0]) &
cpuhw->amasks[i][0]) != 0)
break;
value = nv;
mask |= cpuhw->amasks[i][0];
}
if (i == n_ev)
return 0; /* all OK */
/* doesn't work, gather alternatives... */
if (!ppmu->get_alternatives)
return -1;
for (i = 0; i < n_ev; ++i) {
choice[i] = 0;
n_alt[i] = ppmu->get_alternatives(event_id[i], cflags[i],
cpuhw->alternatives[i]);
for (j = 1; j < n_alt[i]; ++j)
ppmu->get_constraint(cpuhw->alternatives[i][j],
&cpuhw->amasks[i][j],
&cpuhw->avalues[i][j]);
}
/* enumerate all possibilities and see if any will work */
i = 0;
j = -1;
value = mask = nv = 0;
while (i < n_ev) {
if (j >= 0) {
/* we're backtracking, restore context */
value = svalues[i];
mask = smasks[i];
j = choice[i];
}
/*
* See if any alternative k for event_id i,
* where k > j, will satisfy the constraints.
*/
while (++j < n_alt[i]) {
nv = (value | cpuhw->avalues[i][j]) +
(value & cpuhw->avalues[i][j] & addf);
if ((((nv + tadd) ^ value) & mask) == 0 &&
(((nv + tadd) ^ cpuhw->avalues[i][j])
& cpuhw->amasks[i][j]) == 0)
break;
}
if (j >= n_alt[i]) {
/*
* No feasible alternative, backtrack
* to event_id i-1 and continue enumerating its
* alternatives from where we got up to.
*/
if (--i < 0)
return -1;
} else {
/*
* Found a feasible alternative for event_id i,
* remember where we got up to with this event_id,
* go on to the next event_id, and start with
* the first alternative for it.
*/
choice[i] = j;
svalues[i] = value;
smasks[i] = mask;
value = nv;
mask |= cpuhw->amasks[i][j];
++i;
j = -1;
}
}
/* OK, we have a feasible combination, tell the caller the solution */
for (i = 0; i < n_ev; ++i)
event_id[i] = cpuhw->alternatives[i][choice[i]];
return 0;
}
/*
* Check if newly-added events have consistent settings for
* exclude_{user,kernel,hv} with each other and any previously
* added events.
*/
static int check_excludes(struct perf_event **ctrs, unsigned int cflags[],
int n_prev, int n_new)
{
int eu = 0, ek = 0, eh = 0;
int i, n, first;
struct perf_event *event;
n = n_prev + n_new;
if (n <= 1)
return 0;
first = 1;
for (i = 0; i < n; ++i) {
if (cflags[i] & PPMU_LIMITED_PMC_OK) {
cflags[i] &= ~PPMU_LIMITED_PMC_REQD;
continue;
}
event = ctrs[i];
if (first) {
eu = event->attr.exclude_user;
ek = event->attr.exclude_kernel;
eh = event->attr.exclude_hv;
first = 0;
} else if (event->attr.exclude_user != eu ||
event->attr.exclude_kernel != ek ||
event->attr.exclude_hv != eh) {
return -EAGAIN;
}
}
if (eu || ek || eh)
for (i = 0; i < n; ++i)
if (cflags[i] & PPMU_LIMITED_PMC_OK)
cflags[i] |= PPMU_LIMITED_PMC_REQD;
return 0;
}
static void power_pmu_read(struct perf_event *event)
{
s64 val, delta, prev;
if (!event->hw.idx)
return;
/*
* Performance monitor interrupts come even when interrupts
* are soft-disabled, as long as interrupts are hard-enabled.
* Therefore we treat them like NMIs.
*/
do {
prev = atomic64_read(&event->hw.prev_count);
barrier();
val = read_pmc(event->hw.idx);
} while (atomic64_cmpxchg(&event->hw.prev_count, prev, val) != prev);
/* The counters are only 32 bits wide */
delta = (val - prev) & 0xfffffffful;
atomic64_add(delta, &event->count);
atomic64_sub(delta, &event->hw.period_left);
}
/*
* On some machines, PMC5 and PMC6 can't be written, don't respect
* the freeze conditions, and don't generate interrupts. This tells
* us if `event' is using such a PMC.
*/
static int is_limited_pmc(int pmcnum)
{
return (ppmu->flags & PPMU_LIMITED_PMC5_6)
&& (pmcnum == 5 || pmcnum == 6);
}
static void freeze_limited_counters(struct cpu_hw_events *cpuhw,
unsigned long pmc5, unsigned long pmc6)
{
struct perf_event *event;
u64 val, prev, delta;
int i;
for (i = 0; i < cpuhw->n_limited; ++i) {
event = cpuhw->limited_counter[i];
if (!event->hw.idx)
continue;
val = (event->hw.idx == 5) ? pmc5 : pmc6;
prev = atomic64_read(&event->hw.prev_count);
event->hw.idx = 0;
delta = (val - prev) & 0xfffffffful;
atomic64_add(delta, &event->count);
}
}
static void thaw_limited_counters(struct cpu_hw_events *cpuhw,
unsigned long pmc5, unsigned long pmc6)
{
struct perf_event *event;
u64 val;
int i;
for (i = 0; i < cpuhw->n_limited; ++i) {
event = cpuhw->limited_counter[i];
event->hw.idx = cpuhw->limited_hwidx[i];
val = (event->hw.idx == 5) ? pmc5 : pmc6;
atomic64_set(&event->hw.prev_count, val);
perf_event_update_userpage(event);
}
}
/*
* Since limited events don't respect the freeze conditions, we
* have to read them immediately after freezing or unfreezing the
* other events. We try to keep the values from the limited
* events as consistent as possible by keeping the delay (in
* cycles and instructions) between freezing/unfreezing and reading
* the limited events as small and consistent as possible.
* Therefore, if any limited events are in use, we read them
* both, and always in the same order, to minimize variability,
* and do it inside the same asm that writes MMCR0.
*/
static void write_mmcr0(struct cpu_hw_events *cpuhw, unsigned long mmcr0)
{
unsigned long pmc5, pmc6;
if (!cpuhw->n_limited) {
mtspr(SPRN_MMCR0, mmcr0);
return;
}
/*
* Write MMCR0, then read PMC5 and PMC6 immediately.
* To ensure we don't get a performance monitor interrupt
* between writing MMCR0 and freezing/thawing the limited
* events, we first write MMCR0 with the event overflow
* interrupt enable bits turned off.
*/
asm volatile("mtspr %3,%2; mfspr %0,%4; mfspr %1,%5"
: "=&r" (pmc5), "=&r" (pmc6)
: "r" (mmcr0 & ~(MMCR0_PMC1CE | MMCR0_PMCjCE)),
"i" (SPRN_MMCR0),
"i" (SPRN_PMC5), "i" (SPRN_PMC6));
if (mmcr0 & MMCR0_FC)
freeze_limited_counters(cpuhw, pmc5, pmc6);
else
thaw_limited_counters(cpuhw, pmc5, pmc6);
/*
* Write the full MMCR0 including the event overflow interrupt
* enable bits, if necessary.
*/
if (mmcr0 & (MMCR0_PMC1CE | MMCR0_PMCjCE))
mtspr(SPRN_MMCR0, mmcr0);
}
/*
* Disable all events to prevent PMU interrupts and to allow
* events to be added or removed.
*/
void hw_perf_disable(void)
{
struct cpu_hw_events *cpuhw;
unsigned long flags;
if (!ppmu)
return;
local_irq_save(flags);
cpuhw = &__get_cpu_var(cpu_hw_events);
if (!cpuhw->disabled) {
cpuhw->disabled = 1;
cpuhw->n_added = 0;
/*
* Check if we ever enabled the PMU on this cpu.
*/
if (!cpuhw->pmcs_enabled) {
ppc_enable_pmcs();
cpuhw->pmcs_enabled = 1;
}
/*
* Disable instruction sampling if it was enabled
*/
if (cpuhw->mmcr[2] & MMCRA_SAMPLE_ENABLE) {
mtspr(SPRN_MMCRA,
cpuhw->mmcr[2] & ~MMCRA_SAMPLE_ENABLE);
mb();
}
/*
* Set the 'freeze counters' bit.
* The barrier is to make sure the mtspr has been
* executed and the PMU has frozen the events
* before we return.
*/
write_mmcr0(cpuhw, mfspr(SPRN_MMCR0) | MMCR0_FC);
mb();
}
local_irq_restore(flags);
}
/*
* Re-enable all events if disable == 0.
* If we were previously disabled and events were added, then
* put the new config on the PMU.
*/
void hw_perf_enable(void)
{
struct perf_event *event;
struct cpu_hw_events *cpuhw;
unsigned long flags;
long i;
unsigned long val;
s64 left;
unsigned int hwc_index[MAX_HWEVENTS];
int n_lim;
int idx;
if (!ppmu)
return;
local_irq_save(flags);
cpuhw = &__get_cpu_var(cpu_hw_events);
if (!cpuhw->disabled) {
local_irq_restore(flags);
return;
}
cpuhw->disabled = 0;
/*
* If we didn't change anything, or only removed events,
* no need to recalculate MMCR* settings and reset the PMCs.
* Just reenable the PMU with the current MMCR* settings
* (possibly updated for removal of events).
*/
if (!cpuhw->n_added) {
mtspr(SPRN_MMCRA, cpuhw->mmcr[2] & ~MMCRA_SAMPLE_ENABLE);
mtspr(SPRN_MMCR1, cpuhw->mmcr[1]);
if (cpuhw->n_events == 0)
ppc_set_pmu_inuse(0);
goto out_enable;
}
/*
* Compute MMCR* values for the new set of events
*/
if (ppmu->compute_mmcr(cpuhw->events, cpuhw->n_events, hwc_index,
cpuhw->mmcr)) {
/* shouldn't ever get here */
printk(KERN_ERR "oops compute_mmcr failed\n");
goto out;
}
/*
* Add in MMCR0 freeze bits corresponding to the
* attr.exclude_* bits for the first event.
* We have already checked that all events have the
* same values for these bits as the first event.
*/
event = cpuhw->event[0];
if (event->attr.exclude_user)
cpuhw->mmcr[0] |= MMCR0_FCP;
if (event->attr.exclude_kernel)
cpuhw->mmcr[0] |= freeze_events_kernel;
if (event->attr.exclude_hv)
cpuhw->mmcr[0] |= MMCR0_FCHV;
/*
* Write the new configuration to MMCR* with the freeze
* bit set and set the hardware events to their initial values.
* Then unfreeze the events.
*/
ppc_set_pmu_inuse(1);
mtspr(SPRN_MMCRA, cpuhw->mmcr[2] & ~MMCRA_SAMPLE_ENABLE);
mtspr(SPRN_MMCR1, cpuhw->mmcr[1]);
mtspr(SPRN_MMCR0, (cpuhw->mmcr[0] & ~(MMCR0_PMC1CE | MMCR0_PMCjCE))
| MMCR0_FC);
/*
* Read off any pre-existing events that need to move
* to another PMC.
*/
for (i = 0; i < cpuhw->n_events; ++i) {
event = cpuhw->event[i];
if (event->hw.idx && event->hw.idx != hwc_index[i] + 1) {
power_pmu_read(event);
write_pmc(event->hw.idx, 0);
event->hw.idx = 0;
}
}
/*
* Initialize the PMCs for all the new and moved events.
*/
cpuhw->n_limited = n_lim = 0;
for (i = 0; i < cpuhw->n_events; ++i) {
event = cpuhw->event[i];
if (event->hw.idx)
continue;
idx = hwc_index[i] + 1;
if (is_limited_pmc(idx)) {
cpuhw->limited_counter[n_lim] = event;
cpuhw->limited_hwidx[n_lim] = idx;
++n_lim;
continue;
}
val = 0;
if (event->hw.sample_period) {
left = atomic64_read(&event->hw.period_left);
if (left < 0x80000000L)
val = 0x80000000L - left;
}
atomic64_set(&event->hw.prev_count, val);
event->hw.idx = idx;
write_pmc(idx, val);
perf_event_update_userpage(event);
}
cpuhw->n_limited = n_lim;
cpuhw->mmcr[0] |= MMCR0_PMXE | MMCR0_FCECE;
out_enable:
mb();
write_mmcr0(cpuhw, cpuhw->mmcr[0]);
/*
* Enable instruction sampling if necessary
*/
if (cpuhw->mmcr[2] & MMCRA_SAMPLE_ENABLE) {
mb();
mtspr(SPRN_MMCRA, cpuhw->mmcr[2]);
}
out:
local_irq_restore(flags);
}
static int collect_events(struct perf_event *group, int max_count,
struct perf_event *ctrs[], u64 *events,
unsigned int *flags)
{
int n = 0;
struct perf_event *event;
if (!is_software_event(group)) {
if (n >= max_count)
return -1;
ctrs[n] = group;
flags[n] = group->hw.event_base;
events[n++] = group->hw.config;
}
list_for_each_entry(event, &group->sibling_list, group_entry) {
if (!is_software_event(event) &&
event->state != PERF_EVENT_STATE_OFF) {
if (n >= max_count)
return -1;
ctrs[n] = event;
flags[n] = event->hw.event_base;
events[n++] = event->hw.config;
}
}
return n;
}
static void event_sched_in(struct perf_event *event, int cpu)
{
event->state = PERF_EVENT_STATE_ACTIVE;
event->oncpu = cpu;
event->tstamp_running += event->ctx->time - event->tstamp_stopped;
if (is_software_event(event))
event->pmu->enable(event);
}
/*
* Called to enable a whole group of events.
* Returns 1 if the group was enabled, or -EAGAIN if it could not be.
* Assumes the caller has disabled interrupts and has
* frozen the PMU with hw_perf_save_disable.
*/
int hw_perf_group_sched_in(struct perf_event *group_leader,
struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx, int cpu)
{
struct cpu_hw_events *cpuhw;
long i, n, n0;
struct perf_event *sub;
if (!ppmu)
return 0;
cpuhw = &__get_cpu_var(cpu_hw_events);
n0 = cpuhw->n_events;
n = collect_events(group_leader, ppmu->n_counter - n0,
&cpuhw->event[n0], &cpuhw->events[n0],
&cpuhw->flags[n0]);
if (n < 0)
return -EAGAIN;
if (check_excludes(cpuhw->event, cpuhw->flags, n0, n))
return -EAGAIN;
i = power_check_constraints(cpuhw, cpuhw->events, cpuhw->flags, n + n0);
if (i < 0)
return -EAGAIN;
cpuhw->n_events = n0 + n;
cpuhw->n_added += n;
/*
* OK, this group can go on; update event states etc.,
* and enable any software events
*/
for (i = n0; i < n0 + n; ++i)
cpuhw->event[i]->hw.config = cpuhw->events[i];
cpuctx->active_oncpu += n;
n = 1;
event_sched_in(group_leader, cpu);
list_for_each_entry(sub, &group_leader->sibling_list, group_entry) {
if (sub->state != PERF_EVENT_STATE_OFF) {
event_sched_in(sub, cpu);
++n;
}
}
ctx->nr_active += n;
return 1;
}
/*
* Add a event to the PMU.
* If all events are not already frozen, then we disable and
* re-enable the PMU in order to get hw_perf_enable to do the
* actual work of reconfiguring the PMU.
*/
static int power_pmu_enable(struct perf_event *event)
{
struct cpu_hw_events *cpuhw;
unsigned long flags;
int n0;
int ret = -EAGAIN;
local_irq_save(flags);
perf_disable();
/*
* Add the event to the list (if there is room)
* and check whether the total set is still feasible.
*/
cpuhw = &__get_cpu_var(cpu_hw_events);
n0 = cpuhw->n_events;
if (n0 >= ppmu->n_counter)
goto out;
cpuhw->event[n0] = event;
cpuhw->events[n0] = event->hw.config;
cpuhw->flags[n0] = event->hw.event_base;
if (check_excludes(cpuhw->event, cpuhw->flags, n0, 1))
goto out;
if (power_check_constraints(cpuhw, cpuhw->events, cpuhw->flags, n0 + 1))
goto out;
event->hw.config = cpuhw->events[n0];
++cpuhw->n_events;
++cpuhw->n_added;
ret = 0;
out:
perf_enable();
local_irq_restore(flags);
return ret;
}
/*
* Remove a event from the PMU.
*/
static void power_pmu_disable(struct perf_event *event)
{
struct cpu_hw_events *cpuhw;
long i;
unsigned long flags;
local_irq_save(flags);
perf_disable();
power_pmu_read(event);
cpuhw = &__get_cpu_var(cpu_hw_events);
for (i = 0; i < cpuhw->n_events; ++i) {
if (event == cpuhw->event[i]) {
while (++i < cpuhw->n_events)
cpuhw->event[i-1] = cpuhw->event[i];
--cpuhw->n_events;
ppmu->disable_pmc(event->hw.idx - 1, cpuhw->mmcr);
if (event->hw.idx) {
write_pmc(event->hw.idx, 0);
event->hw.idx = 0;
}
perf_event_update_userpage(event);
break;
}
}
for (i = 0; i < cpuhw->n_limited; ++i)
if (event == cpuhw->limited_counter[i])
break;
if (i < cpuhw->n_limited) {
while (++i < cpuhw->n_limited) {
cpuhw->limited_counter[i-1] = cpuhw->limited_counter[i];
cpuhw->limited_hwidx[i-1] = cpuhw->limited_hwidx[i];
}
--cpuhw->n_limited;
}
if (cpuhw->n_events == 0) {
/* disable exceptions if no events are running */
cpuhw->mmcr[0] &= ~(MMCR0_PMXE | MMCR0_FCECE);
}
perf_enable();
local_irq_restore(flags);
}
/*
* Re-enable interrupts on a event after they were throttled
* because they were coming too fast.
*/
static void power_pmu_unthrottle(struct perf_event *event)
{
s64 val, left;
unsigned long flags;
if (!event->hw.idx || !event->hw.sample_period)
return;
local_irq_save(flags);
perf_disable();
power_pmu_read(event);
left = event->hw.sample_period;
event->hw.last_period = left;
val = 0;
if (left < 0x80000000L)
val = 0x80000000L - left;
write_pmc(event->hw.idx, val);
atomic64_set(&event->hw.prev_count, val);
atomic64_set(&event->hw.period_left, left);
perf_event_update_userpage(event);
perf_enable();
local_irq_restore(flags);
}
struct pmu power_pmu = {
.enable = power_pmu_enable,
.disable = power_pmu_disable,
.read = power_pmu_read,
.unthrottle = power_pmu_unthrottle,
};
/*
* Return 1 if we might be able to put event on a limited PMC,
* or 0 if not.
* A event can only go on a limited PMC if it counts something
* that a limited PMC can count, doesn't require interrupts, and
* doesn't exclude any processor mode.
*/
static int can_go_on_limited_pmc(struct perf_event *event, u64 ev,
unsigned int flags)
{
int n;
u64 alt[MAX_EVENT_ALTERNATIVES];
if (event->attr.exclude_user
|| event->attr.exclude_kernel
|| event->attr.exclude_hv
|| event->attr.sample_period)
return 0;
if (ppmu->limited_pmc_event(ev))
return 1;
/*
* The requested event_id isn't on a limited PMC already;
* see if any alternative code goes on a limited PMC.
*/
if (!ppmu->get_alternatives)
return 0;
flags |= PPMU_LIMITED_PMC_OK | PPMU_LIMITED_PMC_REQD;
n = ppmu->get_alternatives(ev, flags, alt);
return n > 0;
}
/*
* Find an alternative event_id that goes on a normal PMC, if possible,
* and return the event_id code, or 0 if there is no such alternative.
* (Note: event_id code 0 is "don't count" on all machines.)
*/
static u64 normal_pmc_alternative(u64 ev, unsigned long flags)
{
u64 alt[MAX_EVENT_ALTERNATIVES];
int n;
flags &= ~(PPMU_LIMITED_PMC_OK | PPMU_LIMITED_PMC_REQD);
n = ppmu->get_alternatives(ev, flags, alt);
if (!n)
return 0;
return alt[0];
}
/* Number of perf_events counting hardware events */
static atomic_t num_events;
/* Used to avoid races in calling reserve/release_pmc_hardware */
static DEFINE_MUTEX(pmc_reserve_mutex);
/*
* Release the PMU if this is the last perf_event.
*/
static void hw_perf_event_destroy(struct perf_event *event)
{
if (!atomic_add_unless(&num_events, -1, 1)) {
mutex_lock(&pmc_reserve_mutex);
if (atomic_dec_return(&num_events) == 0)
release_pmc_hardware();
mutex_unlock(&pmc_reserve_mutex);
}
}
/*
* Translate a generic cache event_id config to a raw event_id code.
*/
static int hw_perf_cache_event(u64 config, u64 *eventp)
{
unsigned long type, op, result;
int ev;
if (!ppmu->cache_events)
return -EINVAL;
/* unpack config */
type = config & 0xff;
op = (config >> 8) & 0xff;
result = (config >> 16) & 0xff;
if (type >= PERF_COUNT_HW_CACHE_MAX ||
op >= PERF_COUNT_HW_CACHE_OP_MAX ||
result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
return -EINVAL;
ev = (*ppmu->cache_events)[type][op][result];
if (ev == 0)
return -EOPNOTSUPP;
if (ev == -1)
return -EINVAL;
*eventp = ev;
return 0;
}
const struct pmu *hw_perf_event_init(struct perf_event *event)
{
u64 ev;
unsigned long flags;
struct perf_event *ctrs[MAX_HWEVENTS];
u64 events[MAX_HWEVENTS];
unsigned int cflags[MAX_HWEVENTS];
int n;
int err;
struct cpu_hw_events *cpuhw;
if (!ppmu)
return ERR_PTR(-ENXIO);
switch (event->attr.type) {
case PERF_TYPE_HARDWARE:
ev = event->attr.config;
if (ev >= ppmu->n_generic || ppmu->generic_events[ev] == 0)
return ERR_PTR(-EOPNOTSUPP);
ev = ppmu->generic_events[ev];
break;
case PERF_TYPE_HW_CACHE:
err = hw_perf_cache_event(event->attr.config, &ev);
if (err)
return ERR_PTR(err);
break;
case PERF_TYPE_RAW:
ev = event->attr.config;
break;
default:
return ERR_PTR(-EINVAL);
}
event->hw.config_base = ev;
event->hw.idx = 0;
/*
* If we are not running on a hypervisor, force the
* exclude_hv bit to 0 so that we don't care what
* the user set it to.
*/
if (!firmware_has_feature(FW_FEATURE_LPAR))
event->attr.exclude_hv = 0;
/*
* If this is a per-task event, then we can use
* PM_RUN_* events interchangeably with their non RUN_*
* equivalents, e.g. PM_RUN_CYC instead of PM_CYC.
* XXX we should check if the task is an idle task.
*/
flags = 0;
if (event->ctx->task)
flags |= PPMU_ONLY_COUNT_RUN;
/*
* If this machine has limited events, check whether this
* event_id could go on a limited event.
*/
if (ppmu->flags & PPMU_LIMITED_PMC5_6) {
if (can_go_on_limited_pmc(event, ev, flags)) {
flags |= PPMU_LIMITED_PMC_OK;
} else if (ppmu->limited_pmc_event(ev)) {
/*
* The requested event_id is on a limited PMC,
* but we can't use a limited PMC; see if any
* alternative goes on a normal PMC.
*/
ev = normal_pmc_alternative(ev, flags);
if (!ev)
return ERR_PTR(-EINVAL);
}
}
/*
* If this is in a group, check if it can go on with all the
* other hardware events in the group. We assume the event
* hasn't been linked into its leader's sibling list at this point.
*/
n = 0;
if (event->group_leader != event) {
n = collect_events(event->group_leader, ppmu->n_counter - 1,
ctrs, events, cflags);
if (n < 0)
return ERR_PTR(-EINVAL);
}
events[n] = ev;
ctrs[n] = event;
cflags[n] = flags;
if (check_excludes(ctrs, cflags, n, 1))
return ERR_PTR(-EINVAL);
cpuhw = &get_cpu_var(cpu_hw_events);
err = power_check_constraints(cpuhw, events, cflags, n + 1);
put_cpu_var(cpu_hw_events);
if (err)
return ERR_PTR(-EINVAL);
event->hw.config = events[n];
event->hw.event_base = cflags[n];
event->hw.last_period = event->hw.sample_period;
atomic64_set(&event->hw.period_left, event->hw.last_period);
/*
* See if we need to reserve the PMU.
* If no events are currently in use, then we have to take a
* mutex to ensure that we don't race with another task doing
* reserve_pmc_hardware or release_pmc_hardware.
*/
err = 0;
if (!atomic_inc_not_zero(&num_events)) {
mutex_lock(&pmc_reserve_mutex);
if (atomic_read(&num_events) == 0 &&
reserve_pmc_hardware(perf_event_interrupt))
err = -EBUSY;
else
atomic_inc(&num_events);
mutex_unlock(&pmc_reserve_mutex);
}
event->destroy = hw_perf_event_destroy;
if (err)
return ERR_PTR(err);
return &power_pmu;
}
/*
* A counter has overflowed; update its count and record
* things if requested. Note that interrupts are hard-disabled
* here so there is no possibility of being interrupted.
*/
static void record_and_restart(struct perf_event *event, unsigned long val,
struct pt_regs *regs, int nmi)
{
u64 period = event->hw.sample_period;
s64 prev, delta, left;
int record = 0;
/* we don't have to worry about interrupts here */
prev = atomic64_read(&event->hw.prev_count);
delta = (val - prev) & 0xfffffffful;
atomic64_add(delta, &event->count);
/*
* See if the total period for this event has expired,
* and update for the next period.
*/
val = 0;
left = atomic64_read(&event->hw.period_left) - delta;
if (period) {
if (left <= 0) {
left += period;
if (left <= 0)
left = period;
record = 1;
}
if (left < 0x80000000LL)
val = 0x80000000LL - left;
}
/*
* Finally record data if requested.
*/
if (record) {
struct perf_sample_data data;
perf_sample_data_init(&data, ~0ULL);
data.period = event->hw.last_period;
if (event->attr.sample_type & PERF_SAMPLE_ADDR)
perf_get_data_addr(regs, &data.addr);
if (perf_event_overflow(event, nmi, &data, regs)) {
/*
* Interrupts are coming too fast - throttle them
* by setting the event to 0, so it will be
* at least 2^30 cycles until the next interrupt
* (assuming each event counts at most 2 counts
* per cycle).
*/
val = 0;
left = ~0ULL >> 1;
}
}
write_pmc(event->hw.idx, val);
atomic64_set(&event->hw.prev_count, val);
atomic64_set(&event->hw.period_left, left);
perf_event_update_userpage(event);
}
/*
* Called from generic code to get the misc flags (i.e. processor mode)
* for an event_id.
*/
unsigned long perf_misc_flags(struct pt_regs *regs)
{
u32 flags = perf_get_misc_flags(regs);
if (flags)
return flags;
return user_mode(regs) ? PERF_RECORD_MISC_USER :
PERF_RECORD_MISC_KERNEL;
}
/*
* Called from generic code to get the instruction pointer
* for an event_id.
*/
unsigned long perf_instruction_pointer(struct pt_regs *regs)
{
unsigned long ip;
if (TRAP(regs) != 0xf00)
return regs->nip; /* not a PMU interrupt */
ip = mfspr(SPRN_SIAR) + perf_ip_adjust(regs);
return ip;
}
/*
* Performance monitor interrupt stuff
*/
static void perf_event_interrupt(struct pt_regs *regs)
{
int i;
struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
struct perf_event *event;
unsigned long val;
int found = 0;
int nmi;
if (cpuhw->n_limited)
freeze_limited_counters(cpuhw, mfspr(SPRN_PMC5),
mfspr(SPRN_PMC6));
perf_read_regs(regs);
nmi = perf_intr_is_nmi(regs);
if (nmi)
nmi_enter();
else
irq_enter();
for (i = 0; i < cpuhw->n_events; ++i) {
event = cpuhw->event[i];
if (!event->hw.idx || is_limited_pmc(event->hw.idx))
continue;
val = read_pmc(event->hw.idx);
if ((int)val < 0) {
/* event has overflowed */
found = 1;
record_and_restart(event, val, regs, nmi);
}
}
/*
* In case we didn't find and reset the event that caused
* the interrupt, scan all events and reset any that are
* negative, to avoid getting continual interrupts.
* Any that we processed in the previous loop will not be negative.
*/
if (!found) {
for (i = 0; i < ppmu->n_counter; ++i) {
if (is_limited_pmc(i + 1))
continue;
val = read_pmc(i + 1);
if ((int)val < 0)
write_pmc(i + 1, 0);
}
}
/*
* Reset MMCR0 to its normal value. This will set PMXE and
* clear FC (freeze counters) and PMAO (perf mon alert occurred)
* and thus allow interrupts to occur again.
* XXX might want to use MSR.PM to keep the events frozen until
* we get back out of this interrupt.
*/
write_mmcr0(cpuhw, cpuhw->mmcr[0]);
if (nmi)
nmi_exit();
else
irq_exit();
}
void hw_perf_event_setup(int cpu)
{
struct cpu_hw_events *cpuhw = &per_cpu(cpu_hw_events, cpu);
if (!ppmu)
return;
memset(cpuhw, 0, sizeof(*cpuhw));
cpuhw->mmcr[0] = MMCR0_FC;
}
int register_power_pmu(struct power_pmu *pmu)
{
if (ppmu)
return -EBUSY; /* something's already registered */
ppmu = pmu;
pr_info("%s performance monitor hardware support registered\n",
pmu->name);
#ifdef MSR_HV
/*
* Use FCHV to ignore kernel events if MSR.HV is set.
*/
if (mfmsr() & MSR_HV)
freeze_events_kernel = MMCR0_FCHV;
#endif /* CONFIG_PPC64 */
return 0;
}