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![Robert Richter](/assets/img/avatar_default.png)
The legacy x86 nmi watchdog code was removed with the implementation of the perf based nmi watchdog. This broke Oprofile's nmi timer mode. To run nmi timer mode we relied on a continuous ticking nmi source which the nmi watchdog provided. The nmi tick was no longer available and current watchdog can not be used anymore since it runs with very long periods in the range of seconds. This patch reimplements the nmi timer mode using a perf counter nmi source. V2: * removing pr_info() * fix undefined reference to `__udivdi3' for 32 bit build * fix section mismatch of .cpuinit.data:nmi_timer_cpu_nb * removed nmi timer setup in arch/x86 * implemented function stubs for op_nmi_init/exit() * made code more readable in oprofile_init() V3: * fix architectural initialization in oprofile_init() * fix CONFIG_OPROFILE_NMI_TIMER dependencies Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Robert Richter <robert.richter@amd.com>
286 lines
5 KiB
C
286 lines
5 KiB
C
/**
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* @file oprof.c
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*
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* @remark Copyright 2002 OProfile authors
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* @remark Read the file COPYING
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*
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* @author John Levon <levon@movementarian.org>
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/oprofile.h>
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#include <linux/moduleparam.h>
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#include <linux/workqueue.h>
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#include <linux/time.h>
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#include <linux/mutex.h>
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#include "oprof.h"
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#include "event_buffer.h"
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#include "cpu_buffer.h"
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#include "buffer_sync.h"
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#include "oprofile_stats.h"
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struct oprofile_operations oprofile_ops;
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unsigned long oprofile_started;
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unsigned long oprofile_backtrace_depth;
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static unsigned long is_setup;
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static DEFINE_MUTEX(start_mutex);
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/* timer
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0 - use performance monitoring hardware if available
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1 - use the timer int mechanism regardless
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*/
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static int timer = 0;
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int oprofile_setup(void)
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{
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int err;
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mutex_lock(&start_mutex);
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if ((err = alloc_cpu_buffers()))
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goto out;
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if ((err = alloc_event_buffer()))
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goto out1;
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if (oprofile_ops.setup && (err = oprofile_ops.setup()))
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goto out2;
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/* Note even though this starts part of the
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* profiling overhead, it's necessary to prevent
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* us missing task deaths and eventually oopsing
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* when trying to process the event buffer.
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*/
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if (oprofile_ops.sync_start) {
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int sync_ret = oprofile_ops.sync_start();
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switch (sync_ret) {
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case 0:
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goto post_sync;
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case 1:
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goto do_generic;
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case -1:
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goto out3;
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default:
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goto out3;
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}
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}
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do_generic:
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if ((err = sync_start()))
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goto out3;
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post_sync:
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is_setup = 1;
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mutex_unlock(&start_mutex);
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return 0;
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out3:
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if (oprofile_ops.shutdown)
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oprofile_ops.shutdown();
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out2:
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free_event_buffer();
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out1:
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free_cpu_buffers();
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out:
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mutex_unlock(&start_mutex);
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return err;
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}
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#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
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static void switch_worker(struct work_struct *work);
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static DECLARE_DELAYED_WORK(switch_work, switch_worker);
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static void start_switch_worker(void)
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{
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if (oprofile_ops.switch_events)
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schedule_delayed_work(&switch_work, oprofile_time_slice);
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}
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static void stop_switch_worker(void)
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{
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cancel_delayed_work_sync(&switch_work);
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}
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static void switch_worker(struct work_struct *work)
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{
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if (oprofile_ops.switch_events())
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return;
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atomic_inc(&oprofile_stats.multiplex_counter);
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start_switch_worker();
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}
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/* User inputs in ms, converts to jiffies */
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int oprofile_set_timeout(unsigned long val_msec)
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{
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int err = 0;
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unsigned long time_slice;
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mutex_lock(&start_mutex);
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if (oprofile_started) {
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err = -EBUSY;
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goto out;
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}
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if (!oprofile_ops.switch_events) {
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err = -EINVAL;
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goto out;
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}
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time_slice = msecs_to_jiffies(val_msec);
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if (time_slice == MAX_JIFFY_OFFSET) {
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err = -EINVAL;
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goto out;
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}
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oprofile_time_slice = time_slice;
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out:
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mutex_unlock(&start_mutex);
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return err;
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}
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#else
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static inline void start_switch_worker(void) { }
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static inline void stop_switch_worker(void) { }
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#endif
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/* Actually start profiling (echo 1>/dev/oprofile/enable) */
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int oprofile_start(void)
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{
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int err = -EINVAL;
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mutex_lock(&start_mutex);
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if (!is_setup)
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goto out;
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err = 0;
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if (oprofile_started)
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goto out;
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oprofile_reset_stats();
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if ((err = oprofile_ops.start()))
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goto out;
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start_switch_worker();
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oprofile_started = 1;
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out:
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mutex_unlock(&start_mutex);
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return err;
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}
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/* echo 0>/dev/oprofile/enable */
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void oprofile_stop(void)
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{
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mutex_lock(&start_mutex);
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if (!oprofile_started)
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goto out;
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oprofile_ops.stop();
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oprofile_started = 0;
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stop_switch_worker();
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/* wake up the daemon to read what remains */
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wake_up_buffer_waiter();
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out:
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mutex_unlock(&start_mutex);
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}
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void oprofile_shutdown(void)
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{
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mutex_lock(&start_mutex);
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if (oprofile_ops.sync_stop) {
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int sync_ret = oprofile_ops.sync_stop();
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switch (sync_ret) {
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case 0:
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goto post_sync;
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case 1:
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goto do_generic;
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default:
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goto post_sync;
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}
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}
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do_generic:
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sync_stop();
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post_sync:
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if (oprofile_ops.shutdown)
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oprofile_ops.shutdown();
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is_setup = 0;
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free_event_buffer();
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free_cpu_buffers();
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mutex_unlock(&start_mutex);
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}
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int oprofile_set_ulong(unsigned long *addr, unsigned long val)
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{
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int err = -EBUSY;
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mutex_lock(&start_mutex);
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if (!oprofile_started) {
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*addr = val;
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err = 0;
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}
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mutex_unlock(&start_mutex);
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return err;
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}
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static int timer_mode;
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static int __init oprofile_init(void)
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{
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int err;
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/* always init architecture to setup backtrace support */
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timer_mode = 0;
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err = oprofile_arch_init(&oprofile_ops);
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if (!err) {
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if (!timer && !oprofilefs_register())
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return 0;
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oprofile_arch_exit();
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}
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/* setup timer mode: */
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timer_mode = 1;
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/* no nmi timer mode if oprofile.timer is set */
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if (timer || op_nmi_timer_init(&oprofile_ops)) {
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err = oprofile_timer_init(&oprofile_ops);
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if (err)
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return err;
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}
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return oprofilefs_register();
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}
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static void __exit oprofile_exit(void)
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{
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oprofilefs_unregister();
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if (!timer_mode)
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oprofile_arch_exit();
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}
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module_init(oprofile_init);
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module_exit(oprofile_exit);
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module_param_named(timer, timer, int, 0644);
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MODULE_PARM_DESC(timer, "force use of timer interrupt");
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("John Levon <levon@movementarian.org>");
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MODULE_DESCRIPTION("OProfile system profiler");
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