![Paul Gortmaker](/assets/img/avatar_default.png)
The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications. For example, the fix in
commit 5e427ec2d0
("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.
After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out. Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.
Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
are flagged as __cpuinit -- so if we remove the __cpuinit from
arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
content into no-ops as early as possible, since that will get rid
of these warnings. In any case, they are temporary and harmless.
This removes all the arch/sh uses of the __cpuinit macros from
all C files. Currently sh does not have any __CPUINIT used in
assembly files.
[1] https://lkml.org/lkml/2013/5/20/589
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: linux-sh@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
401 lines
8.8 KiB
C
401 lines
8.8 KiB
C
/*
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* Performance event support framework for SuperH hardware counters.
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*
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* Copyright (C) 2009 Paul Mundt
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*
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* Heavily based on the x86 and PowerPC implementations.
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*
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* x86:
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* Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
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* Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
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* Copyright (C) 2009 Jaswinder Singh Rajput
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* Copyright (C) 2009 Advanced Micro Devices, Inc., Robert Richter
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* Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
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* Copyright (C) 2009 Intel Corporation, <markus.t.metzger@intel.com>
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*
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* ppc:
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* Copyright 2008-2009 Paul Mackerras, IBM Corporation.
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/irq.h>
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#include <linux/perf_event.h>
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#include <linux/export.h>
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#include <asm/processor.h>
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struct cpu_hw_events {
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struct perf_event *events[MAX_HWEVENTS];
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unsigned long used_mask[BITS_TO_LONGS(MAX_HWEVENTS)];
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unsigned long active_mask[BITS_TO_LONGS(MAX_HWEVENTS)];
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};
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DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events);
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static struct sh_pmu *sh_pmu __read_mostly;
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/* Number of perf_events counting hardware events */
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static atomic_t num_events;
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/* Used to avoid races in calling reserve/release_pmc_hardware */
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static DEFINE_MUTEX(pmc_reserve_mutex);
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/*
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* Stub these out for now, do something more profound later.
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*/
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int reserve_pmc_hardware(void)
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{
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return 0;
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}
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void release_pmc_hardware(void)
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{
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}
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static inline int sh_pmu_initialized(void)
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{
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return !!sh_pmu;
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}
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const char *perf_pmu_name(void)
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{
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if (!sh_pmu)
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return NULL;
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return sh_pmu->name;
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}
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EXPORT_SYMBOL_GPL(perf_pmu_name);
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int perf_num_counters(void)
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{
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if (!sh_pmu)
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return 0;
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return sh_pmu->num_events;
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}
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EXPORT_SYMBOL_GPL(perf_num_counters);
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/*
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* Release the PMU if this is the last perf_event.
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*/
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static void hw_perf_event_destroy(struct perf_event *event)
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{
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if (!atomic_add_unless(&num_events, -1, 1)) {
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mutex_lock(&pmc_reserve_mutex);
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if (atomic_dec_return(&num_events) == 0)
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release_pmc_hardware();
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mutex_unlock(&pmc_reserve_mutex);
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}
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}
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static int hw_perf_cache_event(int config, int *evp)
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{
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unsigned long type, op, result;
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int ev;
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if (!sh_pmu->cache_events)
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return -EINVAL;
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/* unpack config */
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type = config & 0xff;
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op = (config >> 8) & 0xff;
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result = (config >> 16) & 0xff;
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if (type >= PERF_COUNT_HW_CACHE_MAX ||
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op >= PERF_COUNT_HW_CACHE_OP_MAX ||
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result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
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return -EINVAL;
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ev = (*sh_pmu->cache_events)[type][op][result];
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if (ev == 0)
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return -EOPNOTSUPP;
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if (ev == -1)
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return -EINVAL;
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*evp = ev;
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return 0;
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}
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static int __hw_perf_event_init(struct perf_event *event)
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{
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struct perf_event_attr *attr = &event->attr;
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struct hw_perf_event *hwc = &event->hw;
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int config = -1;
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int err;
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if (!sh_pmu_initialized())
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return -ENODEV;
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/*
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* All of the on-chip counters are "limited", in that they have
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* no interrupts, and are therefore unable to do sampling without
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* further work and timer assistance.
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*/
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if (hwc->sample_period)
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return -EINVAL;
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/*
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* See if we need to reserve the counter.
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*
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* If no events are currently in use, then we have to take a
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* mutex to ensure that we don't race with another task doing
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* reserve_pmc_hardware or release_pmc_hardware.
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*/
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err = 0;
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if (!atomic_inc_not_zero(&num_events)) {
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mutex_lock(&pmc_reserve_mutex);
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if (atomic_read(&num_events) == 0 &&
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reserve_pmc_hardware())
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err = -EBUSY;
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else
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atomic_inc(&num_events);
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mutex_unlock(&pmc_reserve_mutex);
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}
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if (err)
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return err;
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event->destroy = hw_perf_event_destroy;
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switch (attr->type) {
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case PERF_TYPE_RAW:
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config = attr->config & sh_pmu->raw_event_mask;
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break;
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case PERF_TYPE_HW_CACHE:
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err = hw_perf_cache_event(attr->config, &config);
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if (err)
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return err;
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break;
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case PERF_TYPE_HARDWARE:
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if (attr->config >= sh_pmu->max_events)
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return -EINVAL;
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config = sh_pmu->event_map(attr->config);
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break;
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}
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if (config == -1)
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return -EINVAL;
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hwc->config |= config;
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return 0;
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}
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static void sh_perf_event_update(struct perf_event *event,
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struct hw_perf_event *hwc, int idx)
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{
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u64 prev_raw_count, new_raw_count;
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s64 delta;
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int shift = 0;
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/*
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* Depending on the counter configuration, they may or may not
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* be chained, in which case the previous counter value can be
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* updated underneath us if the lower-half overflows.
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*
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* Our tactic to handle this is to first atomically read and
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* exchange a new raw count - then add that new-prev delta
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* count to the generic counter atomically.
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*
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* As there is no interrupt associated with the overflow events,
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* this is the simplest approach for maintaining consistency.
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*/
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again:
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prev_raw_count = local64_read(&hwc->prev_count);
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new_raw_count = sh_pmu->read(idx);
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if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
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new_raw_count) != prev_raw_count)
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goto again;
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/*
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* Now we have the new raw value and have updated the prev
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* timestamp already. We can now calculate the elapsed delta
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* (counter-)time and add that to the generic counter.
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*
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* Careful, not all hw sign-extends above the physical width
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* of the count.
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*/
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delta = (new_raw_count << shift) - (prev_raw_count << shift);
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delta >>= shift;
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local64_add(delta, &event->count);
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}
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static void sh_pmu_stop(struct perf_event *event, int flags)
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{
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struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
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struct hw_perf_event *hwc = &event->hw;
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int idx = hwc->idx;
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if (!(event->hw.state & PERF_HES_STOPPED)) {
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sh_pmu->disable(hwc, idx);
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cpuc->events[idx] = NULL;
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event->hw.state |= PERF_HES_STOPPED;
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}
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if ((flags & PERF_EF_UPDATE) && !(event->hw.state & PERF_HES_UPTODATE)) {
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sh_perf_event_update(event, &event->hw, idx);
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event->hw.state |= PERF_HES_UPTODATE;
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}
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}
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static void sh_pmu_start(struct perf_event *event, int flags)
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{
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struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
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struct hw_perf_event *hwc = &event->hw;
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int idx = hwc->idx;
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if (WARN_ON_ONCE(idx == -1))
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return;
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if (flags & PERF_EF_RELOAD)
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WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
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cpuc->events[idx] = event;
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event->hw.state = 0;
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sh_pmu->enable(hwc, idx);
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}
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static void sh_pmu_del(struct perf_event *event, int flags)
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{
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struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
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sh_pmu_stop(event, PERF_EF_UPDATE);
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__clear_bit(event->hw.idx, cpuc->used_mask);
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perf_event_update_userpage(event);
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}
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static int sh_pmu_add(struct perf_event *event, int flags)
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{
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struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
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struct hw_perf_event *hwc = &event->hw;
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int idx = hwc->idx;
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int ret = -EAGAIN;
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perf_pmu_disable(event->pmu);
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if (__test_and_set_bit(idx, cpuc->used_mask)) {
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idx = find_first_zero_bit(cpuc->used_mask, sh_pmu->num_events);
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if (idx == sh_pmu->num_events)
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goto out;
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__set_bit(idx, cpuc->used_mask);
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hwc->idx = idx;
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}
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sh_pmu->disable(hwc, idx);
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event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
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if (flags & PERF_EF_START)
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sh_pmu_start(event, PERF_EF_RELOAD);
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perf_event_update_userpage(event);
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ret = 0;
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out:
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perf_pmu_enable(event->pmu);
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return ret;
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}
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static void sh_pmu_read(struct perf_event *event)
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{
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sh_perf_event_update(event, &event->hw, event->hw.idx);
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}
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static int sh_pmu_event_init(struct perf_event *event)
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{
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int err;
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/* does not support taken branch sampling */
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if (has_branch_stack(event))
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return -EOPNOTSUPP;
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switch (event->attr.type) {
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case PERF_TYPE_RAW:
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case PERF_TYPE_HW_CACHE:
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case PERF_TYPE_HARDWARE:
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err = __hw_perf_event_init(event);
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break;
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default:
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return -ENOENT;
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}
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if (unlikely(err)) {
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if (event->destroy)
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event->destroy(event);
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}
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return err;
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}
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static void sh_pmu_enable(struct pmu *pmu)
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{
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if (!sh_pmu_initialized())
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return;
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sh_pmu->enable_all();
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}
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static void sh_pmu_disable(struct pmu *pmu)
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{
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if (!sh_pmu_initialized())
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return;
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sh_pmu->disable_all();
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}
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static struct pmu pmu = {
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.pmu_enable = sh_pmu_enable,
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.pmu_disable = sh_pmu_disable,
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.event_init = sh_pmu_event_init,
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.add = sh_pmu_add,
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.del = sh_pmu_del,
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.start = sh_pmu_start,
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.stop = sh_pmu_stop,
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.read = sh_pmu_read,
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};
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static void sh_pmu_setup(int cpu)
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{
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struct cpu_hw_events *cpuhw = &per_cpu(cpu_hw_events, cpu);
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memset(cpuhw, 0, sizeof(struct cpu_hw_events));
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}
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static int
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sh_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu)
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{
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unsigned int cpu = (long)hcpu;
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switch (action & ~CPU_TASKS_FROZEN) {
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case CPU_UP_PREPARE:
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sh_pmu_setup(cpu);
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break;
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default:
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break;
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}
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return NOTIFY_OK;
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}
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int register_sh_pmu(struct sh_pmu *_pmu)
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{
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if (sh_pmu)
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return -EBUSY;
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sh_pmu = _pmu;
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pr_info("Performance Events: %s support registered\n", _pmu->name);
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WARN_ON(_pmu->num_events > MAX_HWEVENTS);
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perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW);
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perf_cpu_notifier(sh_pmu_notifier);
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return 0;
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}
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