linux/arch/sh/kernel/perf_event.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Performance event support framework for SuperH hardware counters.
*
* Copyright (C) 2009 Paul Mundt
*
* Heavily based on the x86 and PowerPC implementations.
*
* x86:
* 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
* Copyright (C) 2009 Intel Corporation, <markus.t.metzger@intel.com>
*
* ppc:
* Copyright 2008-2009 Paul Mackerras, IBM Corporation.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/perf_event.h>
#include <linux/export.h>
#include <asm/processor.h>
struct cpu_hw_events {
struct perf_event *events[MAX_HWEVENTS];
unsigned long used_mask[BITS_TO_LONGS(MAX_HWEVENTS)];
unsigned long active_mask[BITS_TO_LONGS(MAX_HWEVENTS)];
};
DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events);
static struct sh_pmu *sh_pmu __read_mostly;
/* 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);
/*
* Stub these out for now, do something more profound later.
*/
int reserve_pmc_hardware(void)
{
return 0;
}
void release_pmc_hardware(void)
{
}
static inline int sh_pmu_initialized(void)
{
return !!sh_pmu;
}
const char *perf_pmu_name(void)
{
if (!sh_pmu)
return NULL;
return sh_pmu->name;
}
EXPORT_SYMBOL_GPL(perf_pmu_name);
int perf_num_counters(void)
{
if (!sh_pmu)
return 0;
return sh_pmu->num_events;
}
EXPORT_SYMBOL_GPL(perf_num_counters);
/*
* 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);
}
}
static int hw_perf_cache_event(int config, int *evp)
{
unsigned long type, op, result;
int ev;
if (!sh_pmu->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 = (*sh_pmu->cache_events)[type][op][result];
if (ev == 0)
return -EOPNOTSUPP;
if (ev == -1)
return -EINVAL;
*evp = ev;
return 0;
}
static int __hw_perf_event_init(struct perf_event *event)
{
struct perf_event_attr *attr = &event->attr;
struct hw_perf_event *hwc = &event->hw;
int config = -1;
int err;
if (!sh_pmu_initialized())
return -ENODEV;
/*
* See if we need to reserve the counter.
*
* 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())
err = -EBUSY;
else
atomic_inc(&num_events);
mutex_unlock(&pmc_reserve_mutex);
}
if (err)
return err;
event->destroy = hw_perf_event_destroy;
switch (attr->type) {
case PERF_TYPE_RAW:
config = attr->config & sh_pmu->raw_event_mask;
break;
case PERF_TYPE_HW_CACHE:
err = hw_perf_cache_event(attr->config, &config);
if (err)
return err;
break;
case PERF_TYPE_HARDWARE:
if (attr->config >= sh_pmu->max_events)
return -EINVAL;
config = sh_pmu->event_map(attr->config);
break;
}
if (config == -1)
return -EINVAL;
hwc->config |= config;
return 0;
}
static void sh_perf_event_update(struct perf_event *event,
struct hw_perf_event *hwc, int idx)
{
u64 prev_raw_count, new_raw_count;
s64 delta;
int shift = 0;
/*
* Depending on the counter configuration, they may or may not
* be chained, in which case the previous counter value can be
* updated underneath us if the lower-half overflows.
*
* 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 counter atomically.
*
* As there is no interrupt associated with the overflow events,
* this is the simplest approach for maintaining consistency.
*/
again:
prev_raw_count = local64_read(&hwc->prev_count);
new_raw_count = sh_pmu->read(idx);
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
* (counter-)time and add that to the generic counter.
*
* 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);
}
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static void sh_pmu_stop(struct perf_event *event, int flags)
{
sh: Replace __get_cpu_var uses __get_cpu_var() is used for multiple purposes in the kernel source. One of them is address calculation via the form &__get_cpu_var(x). This calculates the address for the instance of the percpu variable of the current processor based on an offset. Other use cases are for storing and retrieving data from the current processors percpu area. __get_cpu_var() can be used as an lvalue when writing data or on the right side of an assignment. __get_cpu_var() is defined as : #define __get_cpu_var(var) (*this_cpu_ptr(&(var))) __get_cpu_var() always only does an address determination. However, store and retrieve operations could use a segment prefix (or global register on other platforms) to avoid the address calculation. this_cpu_write() and this_cpu_read() can directly take an offset into a percpu area and use optimized assembly code to read and write per cpu variables. This patch converts __get_cpu_var into either an explicit address calculation using this_cpu_ptr() or into a use of this_cpu operations that use the offset. Thereby address calculations are avoided and less registers are used when code is generated. At the end of the patch set all uses of __get_cpu_var have been removed so the macro is removed too. The patch set includes passes over all arches as well. Once these operations are used throughout then specialized macros can be defined in non -x86 arches as well in order to optimize per cpu access by f.e. using a global register that may be set to the per cpu base. Transformations done to __get_cpu_var() 1. Determine the address of the percpu instance of the current processor. DEFINE_PER_CPU(int, y); int *x = &__get_cpu_var(y); Converts to int *x = this_cpu_ptr(&y); 2. Same as #1 but this time an array structure is involved. DEFINE_PER_CPU(int, y[20]); int *x = __get_cpu_var(y); Converts to int *x = this_cpu_ptr(y); 3. Retrieve the content of the current processors instance of a per cpu variable. DEFINE_PER_CPU(int, y); int x = __get_cpu_var(y) Converts to int x = __this_cpu_read(y); 4. Retrieve the content of a percpu struct DEFINE_PER_CPU(struct mystruct, y); struct mystruct x = __get_cpu_var(y); Converts to memcpy(&x, this_cpu_ptr(&y), sizeof(x)); 5. Assignment to a per cpu variable DEFINE_PER_CPU(int, y) __get_cpu_var(y) = x; Converts to __this_cpu_write(y, x); 6. Increment/Decrement etc of a per cpu variable DEFINE_PER_CPU(int, y); __get_cpu_var(y)++ Converts to __this_cpu_inc(y) Signed-off-by: Christoph Lameter <cl@linux.com> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> [compilation only] Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
struct hw_perf_event *hwc = &event->hw;
int idx = hwc->idx;
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if (!(event->hw.state & PERF_HES_STOPPED)) {
sh_pmu->disable(hwc, idx);
cpuc->events[idx] = NULL;
event->hw.state |= PERF_HES_STOPPED;
}
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if ((flags & PERF_EF_UPDATE) && !(event->hw.state & PERF_HES_UPTODATE)) {
sh_perf_event_update(event, &event->hw, idx);
event->hw.state |= PERF_HES_UPTODATE;
}
}
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static void sh_pmu_start(struct perf_event *event, int flags)
{
sh: Replace __get_cpu_var uses __get_cpu_var() is used for multiple purposes in the kernel source. One of them is address calculation via the form &__get_cpu_var(x). This calculates the address for the instance of the percpu variable of the current processor based on an offset. Other use cases are for storing and retrieving data from the current processors percpu area. __get_cpu_var() can be used as an lvalue when writing data or on the right side of an assignment. __get_cpu_var() is defined as : #define __get_cpu_var(var) (*this_cpu_ptr(&(var))) __get_cpu_var() always only does an address determination. However, store and retrieve operations could use a segment prefix (or global register on other platforms) to avoid the address calculation. this_cpu_write() and this_cpu_read() can directly take an offset into a percpu area and use optimized assembly code to read and write per cpu variables. This patch converts __get_cpu_var into either an explicit address calculation using this_cpu_ptr() or into a use of this_cpu operations that use the offset. Thereby address calculations are avoided and less registers are used when code is generated. At the end of the patch set all uses of __get_cpu_var have been removed so the macro is removed too. The patch set includes passes over all arches as well. Once these operations are used throughout then specialized macros can be defined in non -x86 arches as well in order to optimize per cpu access by f.e. using a global register that may be set to the per cpu base. Transformations done to __get_cpu_var() 1. Determine the address of the percpu instance of the current processor. DEFINE_PER_CPU(int, y); int *x = &__get_cpu_var(y); Converts to int *x = this_cpu_ptr(&y); 2. Same as #1 but this time an array structure is involved. DEFINE_PER_CPU(int, y[20]); int *x = __get_cpu_var(y); Converts to int *x = this_cpu_ptr(y); 3. Retrieve the content of the current processors instance of a per cpu variable. DEFINE_PER_CPU(int, y); int x = __get_cpu_var(y) Converts to int x = __this_cpu_read(y); 4. Retrieve the content of a percpu struct DEFINE_PER_CPU(struct mystruct, y); struct mystruct x = __get_cpu_var(y); Converts to memcpy(&x, this_cpu_ptr(&y), sizeof(x)); 5. Assignment to a per cpu variable DEFINE_PER_CPU(int, y) __get_cpu_var(y) = x; Converts to __this_cpu_write(y, x); 6. Increment/Decrement etc of a per cpu variable DEFINE_PER_CPU(int, y); __get_cpu_var(y)++ Converts to __this_cpu_inc(y) Signed-off-by: Christoph Lameter <cl@linux.com> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> [compilation only] Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
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struct hw_perf_event *hwc = &event->hw;
int idx = hwc->idx;
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if (WARN_ON_ONCE(idx == -1))
return;
if (flags & PERF_EF_RELOAD)
WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
cpuc->events[idx] = event;
event->hw.state = 0;
sh_pmu->enable(hwc, idx);
}
static void sh_pmu_del(struct perf_event *event, int flags)
{
sh: Replace __get_cpu_var uses __get_cpu_var() is used for multiple purposes in the kernel source. One of them is address calculation via the form &__get_cpu_var(x). This calculates the address for the instance of the percpu variable of the current processor based on an offset. Other use cases are for storing and retrieving data from the current processors percpu area. __get_cpu_var() can be used as an lvalue when writing data or on the right side of an assignment. __get_cpu_var() is defined as : #define __get_cpu_var(var) (*this_cpu_ptr(&(var))) __get_cpu_var() always only does an address determination. However, store and retrieve operations could use a segment prefix (or global register on other platforms) to avoid the address calculation. this_cpu_write() and this_cpu_read() can directly take an offset into a percpu area and use optimized assembly code to read and write per cpu variables. This patch converts __get_cpu_var into either an explicit address calculation using this_cpu_ptr() or into a use of this_cpu operations that use the offset. Thereby address calculations are avoided and less registers are used when code is generated. At the end of the patch set all uses of __get_cpu_var have been removed so the macro is removed too. The patch set includes passes over all arches as well. Once these operations are used throughout then specialized macros can be defined in non -x86 arches as well in order to optimize per cpu access by f.e. using a global register that may be set to the per cpu base. Transformations done to __get_cpu_var() 1. Determine the address of the percpu instance of the current processor. DEFINE_PER_CPU(int, y); int *x = &__get_cpu_var(y); Converts to int *x = this_cpu_ptr(&y); 2. Same as #1 but this time an array structure is involved. DEFINE_PER_CPU(int, y[20]); int *x = __get_cpu_var(y); Converts to int *x = this_cpu_ptr(y); 3. Retrieve the content of the current processors instance of a per cpu variable. DEFINE_PER_CPU(int, y); int x = __get_cpu_var(y) Converts to int x = __this_cpu_read(y); 4. Retrieve the content of a percpu struct DEFINE_PER_CPU(struct mystruct, y); struct mystruct x = __get_cpu_var(y); Converts to memcpy(&x, this_cpu_ptr(&y), sizeof(x)); 5. Assignment to a per cpu variable DEFINE_PER_CPU(int, y) __get_cpu_var(y) = x; Converts to __this_cpu_write(y, x); 6. Increment/Decrement etc of a per cpu variable DEFINE_PER_CPU(int, y); __get_cpu_var(y)++ Converts to __this_cpu_inc(y) Signed-off-by: Christoph Lameter <cl@linux.com> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> [compilation only] Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
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sh_pmu_stop(event, PERF_EF_UPDATE);
__clear_bit(event->hw.idx, cpuc->used_mask);
perf_event_update_userpage(event);
}
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static int sh_pmu_add(struct perf_event *event, int flags)
{
sh: Replace __get_cpu_var uses __get_cpu_var() is used for multiple purposes in the kernel source. One of them is address calculation via the form &__get_cpu_var(x). This calculates the address for the instance of the percpu variable of the current processor based on an offset. Other use cases are for storing and retrieving data from the current processors percpu area. __get_cpu_var() can be used as an lvalue when writing data or on the right side of an assignment. __get_cpu_var() is defined as : #define __get_cpu_var(var) (*this_cpu_ptr(&(var))) __get_cpu_var() always only does an address determination. However, store and retrieve operations could use a segment prefix (or global register on other platforms) to avoid the address calculation. this_cpu_write() and this_cpu_read() can directly take an offset into a percpu area and use optimized assembly code to read and write per cpu variables. This patch converts __get_cpu_var into either an explicit address calculation using this_cpu_ptr() or into a use of this_cpu operations that use the offset. Thereby address calculations are avoided and less registers are used when code is generated. At the end of the patch set all uses of __get_cpu_var have been removed so the macro is removed too. The patch set includes passes over all arches as well. Once these operations are used throughout then specialized macros can be defined in non -x86 arches as well in order to optimize per cpu access by f.e. using a global register that may be set to the per cpu base. Transformations done to __get_cpu_var() 1. Determine the address of the percpu instance of the current processor. DEFINE_PER_CPU(int, y); int *x = &__get_cpu_var(y); Converts to int *x = this_cpu_ptr(&y); 2. Same as #1 but this time an array structure is involved. DEFINE_PER_CPU(int, y[20]); int *x = __get_cpu_var(y); Converts to int *x = this_cpu_ptr(y); 3. Retrieve the content of the current processors instance of a per cpu variable. DEFINE_PER_CPU(int, y); int x = __get_cpu_var(y) Converts to int x = __this_cpu_read(y); 4. Retrieve the content of a percpu struct DEFINE_PER_CPU(struct mystruct, y); struct mystruct x = __get_cpu_var(y); Converts to memcpy(&x, this_cpu_ptr(&y), sizeof(x)); 5. Assignment to a per cpu variable DEFINE_PER_CPU(int, y) __get_cpu_var(y) = x; Converts to __this_cpu_write(y, x); 6. Increment/Decrement etc of a per cpu variable DEFINE_PER_CPU(int, y); __get_cpu_var(y)++ Converts to __this_cpu_inc(y) Signed-off-by: Christoph Lameter <cl@linux.com> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> [compilation only] Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
struct hw_perf_event *hwc = &event->hw;
int idx = hwc->idx;
int ret = -EAGAIN;
perf_pmu_disable(event->pmu);
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if (__test_and_set_bit(idx, cpuc->used_mask)) {
idx = find_first_zero_bit(cpuc->used_mask, sh_pmu->num_events);
if (idx == sh_pmu->num_events)
goto out;
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__set_bit(idx, cpuc->used_mask);
hwc->idx = idx;
}
sh_pmu->disable(hwc, idx);
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event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
if (flags & PERF_EF_START)
sh_pmu_start(event, PERF_EF_RELOAD);
perf_event_update_userpage(event);
ret = 0;
out:
perf_pmu_enable(event->pmu);
return ret;
}
static void sh_pmu_read(struct perf_event *event)
{
sh_perf_event_update(event, &event->hw, event->hw.idx);
}
static int sh_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_HW_CACHE:
case PERF_TYPE_HARDWARE:
err = __hw_perf_event_init(event);
break;
default:
return -ENOENT;
}
if (unlikely(err)) {
if (event->destroy)
event->destroy(event);
}
return err;
}
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static void sh_pmu_enable(struct pmu *pmu)
{
if (!sh_pmu_initialized())
return;
sh_pmu->enable_all();
}
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static void sh_pmu_disable(struct pmu *pmu)
{
if (!sh_pmu_initialized())
return;
sh_pmu->disable_all();
}
static struct pmu pmu = {
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.pmu_enable = sh_pmu_enable,
.pmu_disable = sh_pmu_disable,
.event_init = sh_pmu_event_init,
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.add = sh_pmu_add,
.del = sh_pmu_del,
.start = sh_pmu_start,
.stop = sh_pmu_stop,
.read = sh_pmu_read,
};
static int sh_pmu_prepare_cpu(unsigned int cpu)
{
struct cpu_hw_events *cpuhw = &per_cpu(cpu_hw_events, cpu);
memset(cpuhw, 0, sizeof(struct cpu_hw_events));
return 0;
}
int register_sh_pmu(struct sh_pmu *_pmu)
{
if (sh_pmu)
return -EBUSY;
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sh_pmu = _pmu;
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pr_info("Performance Events: %s support registered\n", _pmu->name);
/*
* All of the on-chip counters are "limited", in that they have
* no interrupts, and are therefore unable to do sampling without
* further work and timer assistance.
*/
pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
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WARN_ON(_pmu->num_events > MAX_HWEVENTS);
perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
cpuhp_setup_state(CPUHP_PERF_SUPERH, "PERF_SUPERH", sh_pmu_prepare_cpu,
NULL);
return 0;
}