sparc64: Initial hw perf counter support.

Only supports one simple counter and only UltraSPARC-IIIi chips.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2009-09-10 06:28:20 -07:00
parent 5686f9c3d6
commit 59abbd1e7c
5 changed files with 538 additions and 2 deletions

View file

@ -7,4 +7,7 @@ extern void nmi_adjust_hz(unsigned int new_hz);
extern atomic_t nmi_active;
extern void start_nmi_watchdog(void *unused);
extern void stop_nmi_watchdog(void *unused);
#endif /* __NMI_H */

View file

@ -5,4 +5,10 @@ extern void set_perf_counter_pending(void);
#define PERF_COUNTER_INDEX_OFFSET 0
#ifdef CONFIG_PERF_COUNTERS
extern void init_hw_perf_counters(void);
#else
static inline void init_hw_perf_counters(void) { }
#endif
#endif

View file

@ -103,3 +103,6 @@ obj-$(CONFIG_SUN_LDOMS) += ldc.o vio.o viohs.o ds.o
obj-$(CONFIG_AUDIT) += audit.o
audit--$(CONFIG_AUDIT) := compat_audit.o
obj-$(CONFIG_COMPAT) += $(audit--y)
pc--$(CONFIG_PERF_COUNTERS) := perf_counter.o
obj-$(CONFIG_SPARC64) += $(pc--y)

View file

@ -19,6 +19,7 @@
#include <linux/delay.h>
#include <linux/smp.h>
#include <asm/perf_counter.h>
#include <asm/ptrace.h>
#include <asm/local.h>
#include <asm/pcr.h>
@ -156,7 +157,7 @@ static void report_broken_nmi(int cpu, int *prev_nmi_count)
atomic_dec(&nmi_active);
}
static void stop_nmi_watchdog(void *unused)
void stop_nmi_watchdog(void *unused)
{
pcr_ops->write(PCR_PIC_PRIV);
__get_cpu_var(wd_enabled) = 0;
@ -210,7 +211,7 @@ error:
return err;
}
static void start_nmi_watchdog(void *unused)
void start_nmi_watchdog(void *unused)
{
__get_cpu_var(wd_enabled) = 1;
atomic_inc(&nmi_active);
@ -263,6 +264,9 @@ int __init nmi_init(void)
atomic_set(&nmi_active, -1);
}
}
if (!err)
init_hw_perf_counters();
return err;
}

View file

@ -0,0 +1,520 @@
/* Performance counter support for sparc64.
*
* Copyright (C) 2009 David S. Miller <davem@davemloft.net>
*
* This code is based almost entirely upon the x86 perf counter
* code, which is:
*
* 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>
*/
#include <linux/perf_counter.h>
#include <linux/kprobes.h>
#include <linux/kernel.h>
#include <linux/kdebug.h>
#include <linux/mutex.h>
#include <asm/cpudata.h>
#include <asm/atomic.h>
#include <asm/nmi.h>
#include <asm/pcr.h>
/* Sparc64 chips have two performance counters, 32-bits each, with
* overflow interrupts generated on transition from 0xffffffff to 0.
* The counters are accessed in one go using a 64-bit register.
*
* Both counters are controlled using a single control register. The
* only way to stop all sampling is to clear all of the context (user,
* supervisor, hypervisor) sampling enable bits. But these bits apply
* to both counters, thus the two counters can't be enabled/disabled
* individually.
*
* The control register has two event fields, one for each of the two
* counters. It's thus nearly impossible to have one counter going
* while keeping the other one stopped. Therefore it is possible to
* get overflow interrupts for counters not currently "in use" and
* that condition must be checked in the overflow interrupt handler.
*
* So we use a hack, in that we program inactive counters with the
* "sw_count0" and "sw_count1" events. These count how many times
* the instruction "sethi %hi(0xfc000), %g0" is executed. It's an
* unusual way to encode a NOP and therefore will not trigger in
* normal code.
*/
#define MAX_HWCOUNTERS 2
#define MAX_PERIOD ((1UL << 32) - 1)
#define PIC_UPPER_INDEX 0
#define PIC_LOWER_INDEX 1
#define PIC_UPPER_NOP 0x1c
#define PIC_LOWER_NOP 0x14
struct cpu_hw_counters {
struct perf_counter *counters[MAX_HWCOUNTERS];
unsigned long used_mask[BITS_TO_LONGS(MAX_HWCOUNTERS)];
unsigned long active_mask[BITS_TO_LONGS(MAX_HWCOUNTERS)];
int enabled;
};
DEFINE_PER_CPU(struct cpu_hw_counters, cpu_hw_counters) = { .enabled = 1, };
struct perf_event_map {
u16 encoding;
u8 pic_mask;
#define PIC_NONE 0x00
#define PIC_UPPER 0x01
#define PIC_LOWER 0x02
};
struct sparc_pmu {
const struct perf_event_map *(*event_map)(int);
int max_events;
int upper_shift;
int lower_shift;
int event_mask;
};
static const struct perf_event_map ultra3i_perfmon_event_map[] = {
[PERF_COUNT_HW_CPU_CYCLES] = { 0x0000, PIC_UPPER | PIC_LOWER },
[PERF_COUNT_HW_INSTRUCTIONS] = { 0x0001, PIC_UPPER | PIC_LOWER },
[PERF_COUNT_HW_CACHE_REFERENCES] = { 0x0009, PIC_LOWER },
[PERF_COUNT_HW_CACHE_MISSES] = { 0x0009, PIC_UPPER },
};
static const struct perf_event_map *ultra3i_event_map(int event)
{
return &ultra3i_perfmon_event_map[event];
}
static const struct sparc_pmu ultra3i_pmu = {
.event_map = ultra3i_event_map,
.max_events = ARRAY_SIZE(ultra3i_perfmon_event_map),
.upper_shift = 11,
.lower_shift = 4,
.event_mask = 0x3f,
};
static const struct sparc_pmu *sparc_pmu __read_mostly;
static u64 event_encoding(u64 event, int idx)
{
if (idx == PIC_UPPER_INDEX)
event <<= sparc_pmu->upper_shift;
else
event <<= sparc_pmu->lower_shift;
return event;
}
static u64 mask_for_index(int idx)
{
return event_encoding(sparc_pmu->event_mask, idx);
}
static u64 nop_for_index(int idx)
{
return event_encoding(idx == PIC_UPPER_INDEX ?
PIC_UPPER_NOP : PIC_LOWER_NOP, idx);
}
static inline void sparc_pmu_enable_counter(struct hw_perf_counter *hwc,
int idx)
{
u64 val, mask = mask_for_index(idx);
val = pcr_ops->read();
pcr_ops->write((val & ~mask) | hwc->config);
}
static inline void sparc_pmu_disable_counter(struct hw_perf_counter *hwc,
int idx)
{
u64 mask = mask_for_index(idx);
u64 nop = nop_for_index(idx);
u64 val = pcr_ops->read();
pcr_ops->write((val & ~mask) | nop);
}
void hw_perf_enable(void)
{
struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
u64 val;
int i;
if (cpuc->enabled)
return;
cpuc->enabled = 1;
barrier();
val = pcr_ops->read();
for (i = 0; i < MAX_HWCOUNTERS; i++) {
struct perf_counter *cp = cpuc->counters[i];
struct hw_perf_counter *hwc;
if (!cp)
continue;
hwc = &cp->hw;
val |= hwc->config_base;
}
pcr_ops->write(val);
}
void hw_perf_disable(void)
{
struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
u64 val;
if (!cpuc->enabled)
return;
cpuc->enabled = 0;
val = pcr_ops->read();
val &= ~(PCR_UTRACE | PCR_STRACE);
pcr_ops->write(val);
}
static u32 read_pmc(int idx)
{
u64 val;
read_pic(val);
if (idx == PIC_UPPER_INDEX)
val >>= 32;
return val & 0xffffffff;
}
static void write_pmc(int idx, u64 val)
{
u64 shift, mask, pic;
shift = 0;
if (idx == PIC_UPPER_INDEX)
shift = 32;
mask = ((u64) 0xffffffff) << shift;
val <<= shift;
read_pic(pic);
pic &= ~mask;
pic |= val;
write_pic(pic);
}
static int sparc_perf_counter_set_period(struct perf_counter *counter,
struct hw_perf_counter *hwc, int idx)
{
s64 left = atomic64_read(&hwc->period_left);
s64 period = hwc->sample_period;
int ret = 0;
if (unlikely(left <= -period)) {
left = period;
atomic64_set(&hwc->period_left, left);
hwc->last_period = period;
ret = 1;
}
if (unlikely(left <= 0)) {
left += period;
atomic64_set(&hwc->period_left, left);
hwc->last_period = period;
ret = 1;
}
if (left > MAX_PERIOD)
left = MAX_PERIOD;
atomic64_set(&hwc->prev_count, (u64)-left);
write_pmc(idx, (u64)(-left) & 0xffffffff);
perf_counter_update_userpage(counter);
return ret;
}
static int sparc_pmu_enable(struct perf_counter *counter)
{
struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
struct hw_perf_counter *hwc = &counter->hw;
int idx = hwc->idx;
if (test_and_set_bit(idx, cpuc->used_mask))
return -EAGAIN;
sparc_pmu_disable_counter(hwc, idx);
cpuc->counters[idx] = counter;
set_bit(idx, cpuc->active_mask);
sparc_perf_counter_set_period(counter, hwc, idx);
sparc_pmu_enable_counter(hwc, idx);
perf_counter_update_userpage(counter);
return 0;
}
static u64 sparc_perf_counter_update(struct perf_counter *counter,
struct hw_perf_counter *hwc, int idx)
{
int shift = 64 - 32;
u64 prev_raw_count, new_raw_count;
s64 delta;
again:
prev_raw_count = atomic64_read(&hwc->prev_count);
new_raw_count = read_pmc(idx);
if (atomic64_cmpxchg(&hwc->prev_count, prev_raw_count,
new_raw_count) != prev_raw_count)
goto again;
delta = (new_raw_count << shift) - (prev_raw_count << shift);
delta >>= shift;
atomic64_add(delta, &counter->count);
atomic64_sub(delta, &hwc->period_left);
return new_raw_count;
}
static void sparc_pmu_disable(struct perf_counter *counter)
{
struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
struct hw_perf_counter *hwc = &counter->hw;
int idx = hwc->idx;
clear_bit(idx, cpuc->active_mask);
sparc_pmu_disable_counter(hwc, idx);
barrier();
sparc_perf_counter_update(counter, hwc, idx);
cpuc->counters[idx] = NULL;
clear_bit(idx, cpuc->used_mask);
perf_counter_update_userpage(counter);
}
static void sparc_pmu_read(struct perf_counter *counter)
{
struct hw_perf_counter *hwc = &counter->hw;
sparc_perf_counter_update(counter, hwc, hwc->idx);
}
static void sparc_pmu_unthrottle(struct perf_counter *counter)
{
struct hw_perf_counter *hwc = &counter->hw;
sparc_pmu_enable_counter(hwc, hwc->idx);
}
static atomic_t active_counters = ATOMIC_INIT(0);
static DEFINE_MUTEX(pmc_grab_mutex);
void perf_counter_grab_pmc(void)
{
if (atomic_inc_not_zero(&active_counters))
return;
mutex_lock(&pmc_grab_mutex);
if (atomic_read(&active_counters) == 0) {
if (atomic_read(&nmi_active) > 0) {
on_each_cpu(stop_nmi_watchdog, NULL, 1);
BUG_ON(atomic_read(&nmi_active) != 0);
}
atomic_inc(&active_counters);
}
mutex_unlock(&pmc_grab_mutex);
}
void perf_counter_release_pmc(void)
{
if (atomic_dec_and_mutex_lock(&active_counters, &pmc_grab_mutex)) {
if (atomic_read(&nmi_active) == 0)
on_each_cpu(start_nmi_watchdog, NULL, 1);
mutex_unlock(&pmc_grab_mutex);
}
}
static void hw_perf_counter_destroy(struct perf_counter *counter)
{
perf_counter_release_pmc();
}
static int __hw_perf_counter_init(struct perf_counter *counter)
{
struct perf_counter_attr *attr = &counter->attr;
struct hw_perf_counter *hwc = &counter->hw;
const struct perf_event_map *pmap;
u64 enc;
if (atomic_read(&nmi_active) < 0)
return -ENODEV;
if (attr->type != PERF_TYPE_HARDWARE)
return -EOPNOTSUPP;
if (attr->config >= sparc_pmu->max_events)
return -EINVAL;
perf_counter_grab_pmc();
counter->destroy = hw_perf_counter_destroy;
/* We save the enable bits in the config_base. So to
* turn off sampling just write 'config', and to enable
* things write 'config | config_base'.
*/
hwc->config_base = 0;
if (!attr->exclude_user)
hwc->config_base |= PCR_UTRACE;
if (!attr->exclude_kernel)
hwc->config_base |= PCR_STRACE;
if (!hwc->sample_period) {
hwc->sample_period = MAX_PERIOD;
hwc->last_period = hwc->sample_period;
atomic64_set(&hwc->period_left, hwc->sample_period);
}
pmap = sparc_pmu->event_map(attr->config);
enc = pmap->encoding;
if (pmap->pic_mask & PIC_UPPER) {
hwc->idx = PIC_UPPER_INDEX;
enc <<= sparc_pmu->upper_shift;
} else {
hwc->idx = PIC_LOWER_INDEX;
enc <<= sparc_pmu->lower_shift;
}
hwc->config |= enc;
return 0;
}
static const struct pmu pmu = {
.enable = sparc_pmu_enable,
.disable = sparc_pmu_disable,
.read = sparc_pmu_read,
.unthrottle = sparc_pmu_unthrottle,
};
const struct pmu *hw_perf_counter_init(struct perf_counter *counter)
{
int err = __hw_perf_counter_init(counter);
if (err)
return ERR_PTR(err);
return &pmu;
}
void perf_counter_print_debug(void)
{
unsigned long flags;
u64 pcr, pic;
int cpu;
if (!sparc_pmu)
return;
local_irq_save(flags);
cpu = smp_processor_id();
pcr = pcr_ops->read();
read_pic(pic);
pr_info("\n");
pr_info("CPU#%d: PCR[%016llx] PIC[%016llx]\n",
cpu, pcr, pic);
local_irq_restore(flags);
}
static int __kprobes perf_counter_nmi_handler(struct notifier_block *self,
unsigned long cmd, void *__args)
{
struct die_args *args = __args;
struct perf_sample_data data;
struct cpu_hw_counters *cpuc;
struct pt_regs *regs;
int idx;
if (!atomic_read(&active_counters))
return NOTIFY_DONE;
switch (cmd) {
case DIE_NMI:
break;
default:
return NOTIFY_DONE;
}
regs = args->regs;
data.regs = regs;
data.addr = 0;
cpuc = &__get_cpu_var(cpu_hw_counters);
for (idx = 0; idx < MAX_HWCOUNTERS; idx++) {
struct perf_counter *counter = cpuc->counters[idx];
struct hw_perf_counter *hwc;
u64 val;
if (!test_bit(idx, cpuc->active_mask))
continue;
hwc = &counter->hw;
val = sparc_perf_counter_update(counter, hwc, idx);
if (val & (1ULL << 31))
continue;
data.period = counter->hw.last_period;
if (!sparc_perf_counter_set_period(counter, hwc, idx))
continue;
if (perf_counter_overflow(counter, 1, &data))
sparc_pmu_disable_counter(hwc, idx);
}
return NOTIFY_STOP;
}
static __read_mostly struct notifier_block perf_counter_nmi_notifier = {
.notifier_call = perf_counter_nmi_handler,
};
static bool __init supported_pmu(void)
{
if (!strcmp(sparc_pmu_type, "ultra3i")) {
sparc_pmu = &ultra3i_pmu;
return true;
}
return false;
}
void __init init_hw_perf_counters(void)
{
pr_info("Performance counters: ");
if (!supported_pmu()) {
pr_cont("No support for PMU type '%s'\n", sparc_pmu_type);
return;
}
pr_cont("Supported PMU type is '%s'\n", sparc_pmu_type);
/* All sparc64 PMUs currently have 2 counters. But this simple
* driver only supports one active counter at a time.
*/
perf_max_counters = 1;
register_die_notifier(&perf_counter_nmi_notifier);
}