2008-11-25 08:24:15 +00:00
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/*
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2009-03-13 10:54:40 +00:00
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* h/w branch tracer for x86 based on BTS
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2008-11-25 08:24:15 +00:00
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*
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2009-01-19 09:26:53 +00:00
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* Copyright (C) 2008-2009 Intel Corporation.
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* Markus Metzger <markus.t.metzger@gmail.com>, 2008-2009
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2008-11-25 08:24:15 +00:00
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*/
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2009-02-25 07:40:09 +00:00
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#include <linux/kallsyms.h>
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2008-11-25 08:24:15 +00:00
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#include <linux/debugfs.h>
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#include <linux/ftrace.h>
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2009-02-25 07:40:09 +00:00
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#include <linux/module.h>
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2009-01-19 09:26:53 +00:00
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#include <linux/cpu.h>
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#include <linux/smp.h>
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2009-02-25 07:40:09 +00:00
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#include <linux/fs.h>
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2008-11-25 08:24:15 +00:00
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#include <asm/ds.h>
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2008-12-24 04:24:12 +00:00
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#include "trace_output.h"
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2009-03-13 10:54:40 +00:00
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#include "trace.h"
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2008-11-25 08:24:15 +00:00
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2009-03-13 09:48:52 +00:00
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#define BTS_BUFFER_SIZE (1 << 13)
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2008-11-25 08:24:15 +00:00
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static DEFINE_PER_CPU(struct bts_tracer *, tracer);
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2009-03-13 09:48:52 +00:00
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static DEFINE_PER_CPU(unsigned char[BTS_BUFFER_SIZE], buffer);
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2008-11-25 08:24:15 +00:00
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#define this_tracer per_cpu(tracer, smp_processor_id())
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2009-03-13 09:48:52 +00:00
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static int trace_hw_branches_enabled __read_mostly;
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static int trace_hw_branches_suspended __read_mostly;
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2009-01-19 09:31:01 +00:00
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static struct trace_array *hw_branch_trace __read_mostly;
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2008-11-25 08:24:15 +00:00
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2009-01-19 09:26:53 +00:00
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2009-04-03 14:43:40 +00:00
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static void bts_trace_init_cpu(int cpu)
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2008-11-25 08:24:15 +00:00
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{
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2009-04-03 14:43:40 +00:00
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per_cpu(tracer, cpu) =
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ds_request_bts_cpu(cpu, per_cpu(buffer, cpu), BTS_BUFFER_SIZE,
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NULL, (size_t)-1, BTS_KERNEL);
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2008-12-11 12:53:26 +00:00
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2009-04-03 14:43:40 +00:00
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if (IS_ERR(per_cpu(tracer, cpu)))
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per_cpu(tracer, cpu) = NULL;
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2008-11-25 08:24:15 +00:00
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}
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2009-03-13 09:48:52 +00:00
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static int bts_trace_init(struct trace_array *tr)
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2008-11-25 08:24:15 +00:00
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{
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2009-04-03 14:43:40 +00:00
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int cpu;
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2008-11-25 08:24:15 +00:00
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2009-03-13 09:48:52 +00:00
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hw_branch_trace = tr;
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2009-04-03 14:43:40 +00:00
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trace_hw_branches_enabled = 0;
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2008-11-25 08:24:15 +00:00
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2009-04-03 14:43:40 +00:00
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get_online_cpus();
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for_each_online_cpu(cpu) {
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bts_trace_init_cpu(cpu);
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2008-11-25 08:24:15 +00:00
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2009-04-03 14:43:40 +00:00
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if (likely(per_cpu(tracer, cpu)))
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trace_hw_branches_enabled = 1;
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}
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2009-03-13 09:48:52 +00:00
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trace_hw_branches_suspended = 0;
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2009-04-03 14:43:40 +00:00
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put_online_cpus();
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2009-03-13 09:48:52 +00:00
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/* If we could not enable tracing on a single cpu, we fail. */
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2009-04-03 14:43:40 +00:00
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return trace_hw_branches_enabled ? 0 : -EOPNOTSUPP;
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2008-11-25 08:24:15 +00:00
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}
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2009-03-13 09:48:52 +00:00
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static void bts_trace_reset(struct trace_array *tr)
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2008-11-25 08:24:15 +00:00
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{
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2009-04-03 14:43:40 +00:00
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int cpu;
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2009-01-19 09:26:53 +00:00
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2009-04-03 14:43:40 +00:00
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get_online_cpus();
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for_each_online_cpu(cpu) {
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if (likely(per_cpu(tracer, cpu))) {
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ds_release_bts(per_cpu(tracer, cpu));
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per_cpu(tracer, cpu) = NULL;
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}
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2008-11-25 08:24:15 +00:00
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}
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2009-01-19 09:26:53 +00:00
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trace_hw_branches_enabled = 0;
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2009-03-13 09:48:52 +00:00
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trace_hw_branches_suspended = 0;
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2009-04-03 14:43:40 +00:00
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put_online_cpus();
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2008-11-25 08:24:15 +00:00
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}
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2009-03-13 09:48:52 +00:00
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static void bts_trace_start(struct trace_array *tr)
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2008-11-25 08:24:15 +00:00
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{
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2009-04-03 14:43:40 +00:00
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int cpu;
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2009-01-19 09:26:53 +00:00
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2009-04-03 14:43:40 +00:00
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get_online_cpus();
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for_each_online_cpu(cpu)
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if (likely(per_cpu(tracer, cpu)))
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ds_resume_bts(per_cpu(tracer, cpu));
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2009-03-13 09:48:52 +00:00
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trace_hw_branches_suspended = 0;
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2009-04-03 14:43:40 +00:00
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put_online_cpus();
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2009-03-13 09:48:52 +00:00
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}
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2008-11-25 08:24:15 +00:00
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2009-03-13 09:48:52 +00:00
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static void bts_trace_stop(struct trace_array *tr)
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{
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2009-04-03 14:43:40 +00:00
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int cpu;
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2009-03-13 09:48:52 +00:00
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2009-04-03 14:43:40 +00:00
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get_online_cpus();
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for_each_online_cpu(cpu)
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if (likely(per_cpu(tracer, cpu)))
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ds_suspend_bts(per_cpu(tracer, cpu));
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2009-03-13 09:48:52 +00:00
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trace_hw_branches_suspended = 1;
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2009-04-03 14:43:40 +00:00
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put_online_cpus();
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2009-01-19 09:26:53 +00:00
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}
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static int __cpuinit bts_hotcpu_handler(struct notifier_block *nfb,
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unsigned long action, void *hcpu)
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{
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2009-04-03 14:43:40 +00:00
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int cpu = (long)hcpu;
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2009-01-19 09:26:53 +00:00
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switch (action) {
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case CPU_ONLINE:
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case CPU_DOWN_FAILED:
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2009-04-03 14:43:40 +00:00
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/* The notification is sent with interrupts enabled. */
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if (trace_hw_branches_enabled) {
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bts_trace_init_cpu(cpu);
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if (trace_hw_branches_suspended &&
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likely(per_cpu(tracer, cpu)))
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ds_suspend_bts(per_cpu(tracer, cpu));
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}
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2009-01-19 09:26:53 +00:00
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break;
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2009-04-03 14:43:40 +00:00
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2009-01-19 09:26:53 +00:00
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case CPU_DOWN_PREPARE:
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2009-04-03 14:43:40 +00:00
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/* The notification is sent with interrupts enabled. */
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if (likely(per_cpu(tracer, cpu))) {
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ds_release_bts(per_cpu(tracer, cpu));
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per_cpu(tracer, cpu) = NULL;
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}
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2009-01-19 09:26:53 +00:00
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}
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return NOTIFY_DONE;
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2008-11-25 08:24:15 +00:00
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}
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2009-01-19 09:26:53 +00:00
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static struct notifier_block bts_hotcpu_notifier __cpuinitdata = {
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.notifier_call = bts_hotcpu_handler
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};
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2008-11-25 08:24:15 +00:00
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static void bts_trace_print_header(struct seq_file *m)
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{
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2009-01-19 09:29:16 +00:00
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seq_puts(m, "# CPU# TO <- FROM\n");
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2008-11-25 08:24:15 +00:00
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}
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static enum print_line_t bts_trace_print_line(struct trace_iterator *iter)
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{
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2009-03-13 10:54:40 +00:00
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unsigned long symflags = TRACE_ITER_SYM_OFFSET;
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2008-11-25 08:24:15 +00:00
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struct trace_entry *entry = iter->ent;
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struct trace_seq *seq = &iter->seq;
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2008-12-11 12:53:26 +00:00
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struct hw_branch_entry *it;
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2008-11-25 08:24:15 +00:00
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trace_assign_type(it, entry);
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2008-12-11 12:53:26 +00:00
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if (entry->type == TRACE_HW_BRANCHES) {
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2009-02-08 00:38:43 +00:00
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if (trace_seq_printf(seq, "%4d ", iter->cpu) &&
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2009-01-19 09:29:16 +00:00
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seq_print_ip_sym(seq, it->to, symflags) &&
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trace_seq_printf(seq, "\t <- ") &&
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seq_print_ip_sym(seq, it->from, symflags) &&
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2008-12-11 12:53:26 +00:00
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trace_seq_printf(seq, "\n"))
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return TRACE_TYPE_HANDLED;
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return TRACE_TYPE_PARTIAL_LINE;;
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2008-11-25 08:24:15 +00:00
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}
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return TRACE_TYPE_UNHANDLED;
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}
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2009-01-19 09:31:01 +00:00
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void trace_hw_branch(u64 from, u64 to)
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2008-11-25 08:24:15 +00:00
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{
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2009-03-31 05:48:49 +00:00
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struct ftrace_event_call *call = &event_hw_branch;
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2009-01-19 09:31:01 +00:00
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struct trace_array *tr = hw_branch_trace;
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2008-11-25 08:24:15 +00:00
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struct ring_buffer_event *event;
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2008-12-11 12:53:26 +00:00
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struct hw_branch_entry *entry;
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2009-02-05 18:12:56 +00:00
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unsigned long irq1;
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2009-01-19 09:26:53 +00:00
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int cpu;
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2008-11-25 08:24:15 +00:00
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2009-01-19 09:26:53 +00:00
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if (unlikely(!tr))
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return;
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if (unlikely(!trace_hw_branches_enabled))
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2008-11-25 08:24:15 +00:00
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return;
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2009-01-19 09:26:53 +00:00
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local_irq_save(irq1);
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cpu = raw_smp_processor_id();
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if (atomic_inc_return(&tr->data[cpu]->disabled) != 1)
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goto out;
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tracing: Introduce trace_buffer_{lock_reserve,unlock_commit}
Impact: new API
These new functions do what previously was being open coded, reducing
the number of details ftrace plugin writers have to worry about.
It also standardizes the handling of stacktrace, userstacktrace and
other trace options we may introduce in the future.
With this patch, for instance, the blk tracer (and some others already
in the tree) can use the "userstacktrace" /d/tracing/trace_options
facility.
$ codiff /tmp/vmlinux.before /tmp/vmlinux.after
linux-2.6-tip/kernel/trace/trace.c:
trace_vprintk | -5
trace_graph_return | -22
trace_graph_entry | -26
trace_function | -45
__ftrace_trace_stack | -27
ftrace_trace_userstack | -29
tracing_sched_switch_trace | -66
tracing_stop | +1
trace_seq_to_user | -1
ftrace_trace_special | -63
ftrace_special | +1
tracing_sched_wakeup_trace | -70
tracing_reset_online_cpus | -1
13 functions changed, 2 bytes added, 355 bytes removed, diff: -353
linux-2.6-tip/block/blktrace.c:
__blk_add_trace | -58
1 function changed, 58 bytes removed, diff: -58
linux-2.6-tip/kernel/trace/trace.c:
trace_buffer_lock_reserve | +88
trace_buffer_unlock_commit | +86
2 functions changed, 174 bytes added, diff: +174
/tmp/vmlinux.after:
16 functions changed, 176 bytes added, 413 bytes removed, diff: -237
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frédéric Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-05 18:14:13 +00:00
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event = trace_buffer_lock_reserve(tr, TRACE_HW_BRANCHES,
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sizeof(*entry), 0, 0);
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2009-01-19 09:26:53 +00:00
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if (!event)
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goto out;
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2008-11-25 08:24:15 +00:00
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entry = ring_buffer_event_data(event);
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tracing_generic_entry_update(&entry->ent, 0, from);
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2008-12-11 12:53:26 +00:00
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entry->ent.type = TRACE_HW_BRANCHES;
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2008-11-25 08:24:15 +00:00
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entry->from = from;
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entry->to = to;
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2009-04-08 08:15:54 +00:00
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if (!filter_check_discard(call, entry, tr->buffer, event))
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trace_buffer_unlock_commit(tr, event, 0, 0);
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2009-01-19 09:26:53 +00:00
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out:
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atomic_dec(&tr->data[cpu]->disabled);
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local_irq_restore(irq1);
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2008-11-25 08:24:15 +00:00
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}
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2009-01-19 09:31:01 +00:00
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static void trace_bts_at(const struct bts_trace *trace, void *at)
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2008-11-25 08:24:15 +00:00
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{
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2008-12-11 12:53:26 +00:00
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struct bts_struct bts;
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int err = 0;
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2008-11-25 08:24:15 +00:00
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2008-12-11 12:53:26 +00:00
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WARN_ON_ONCE(!trace->read);
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if (!trace->read)
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2008-11-25 08:24:15 +00:00
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return;
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2008-12-11 12:53:26 +00:00
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err = trace->read(this_tracer, at, &bts);
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if (err < 0)
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return;
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2008-11-25 08:24:15 +00:00
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2008-12-11 12:53:26 +00:00
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switch (bts.qualifier) {
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case BTS_BRANCH:
|
2009-01-19 09:31:01 +00:00
|
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trace_hw_branch(bts.variant.lbr.from, bts.variant.lbr.to);
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2008-12-11 12:53:26 +00:00
|
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break;
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}
|
2008-11-25 08:24:15 +00:00
|
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}
|
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|
2009-01-19 09:26:53 +00:00
|
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/*
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* Collect the trace on the current cpu and write it into the ftrace buffer.
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*
|
2009-04-03 14:43:40 +00:00
|
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* pre: tracing must be suspended on the current cpu
|
2009-01-19 09:26:53 +00:00
|
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*/
|
2008-11-25 08:24:15 +00:00
|
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static void trace_bts_cpu(void *arg)
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|
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{
|
2009-03-13 09:48:52 +00:00
|
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struct trace_array *tr = (struct trace_array *)arg;
|
2008-12-11 12:53:26 +00:00
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const struct bts_trace *trace;
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unsigned char *at;
|
2008-11-25 08:24:15 +00:00
|
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2009-01-19 09:31:01 +00:00
|
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if (unlikely(!tr))
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2008-11-25 08:24:15 +00:00
|
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return;
|
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|
2009-01-19 09:26:53 +00:00
|
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if (unlikely(atomic_read(&tr->data[raw_smp_processor_id()]->disabled)))
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return;
|
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|
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|
2009-01-19 09:31:01 +00:00
|
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|
if (unlikely(!this_tracer))
|
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return;
|
|
|
|
|
2008-12-11 12:53:26 +00:00
|
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|
trace = ds_read_bts(this_tracer);
|
|
|
|
if (!trace)
|
2009-04-03 14:43:40 +00:00
|
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|
return;
|
2008-11-25 08:24:15 +00:00
|
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|
|
2008-12-11 12:53:26 +00:00
|
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|
for (at = trace->ds.top; (void *)at < trace->ds.end;
|
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at += trace->ds.size)
|
2009-01-19 09:31:01 +00:00
|
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|
trace_bts_at(trace, at);
|
2008-11-25 08:24:15 +00:00
|
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|
2008-12-11 12:53:26 +00:00
|
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for (at = trace->ds.begin; (void *)at < trace->ds.top;
|
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at += trace->ds.size)
|
2009-01-19 09:31:01 +00:00
|
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|
trace_bts_at(trace, at);
|
2008-11-25 08:24:15 +00:00
|
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|
}
|
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static void trace_bts_prepare(struct trace_iterator *iter)
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{
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2009-04-03 14:43:40 +00:00
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int cpu;
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2009-01-19 09:26:53 +00:00
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2009-04-03 14:43:40 +00:00
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get_online_cpus();
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for_each_online_cpu(cpu)
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if (likely(per_cpu(tracer, cpu)))
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ds_suspend_bts(per_cpu(tracer, cpu));
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/*
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* We need to collect the trace on the respective cpu since ftrace
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* implicitly adds the record for the current cpu.
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* Once that is more flexible, we could collect the data from any cpu.
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*/
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2009-01-19 09:26:53 +00:00
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on_each_cpu(trace_bts_cpu, iter->tr, 1);
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2008-11-25 08:24:15 +00:00
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2009-04-03 14:43:40 +00:00
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for_each_online_cpu(cpu)
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if (likely(per_cpu(tracer, cpu)))
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ds_resume_bts(per_cpu(tracer, cpu));
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put_online_cpus();
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2008-11-25 08:24:15 +00:00
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}
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2009-01-19 09:33:31 +00:00
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static void trace_bts_close(struct trace_iterator *iter)
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{
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tracing_reset_online_cpus(iter->tr);
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}
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2009-01-19 09:31:01 +00:00
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void trace_hw_branch_oops(void)
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{
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2009-04-03 14:43:40 +00:00
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if (this_tracer) {
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ds_suspend_bts_noirq(this_tracer);
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2009-03-13 09:48:52 +00:00
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trace_bts_cpu(hw_branch_trace);
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2009-04-03 14:43:40 +00:00
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ds_resume_bts_noirq(this_tracer);
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}
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2009-01-19 09:31:01 +00:00
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}
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2008-11-25 08:24:15 +00:00
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struct tracer bts_tracer __read_mostly =
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{
|
2008-12-11 12:53:26 +00:00
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.name = "hw-branch-tracer",
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2008-11-25 08:24:15 +00:00
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.init = bts_trace_init,
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2009-01-19 09:26:53 +00:00
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.reset = bts_trace_reset,
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2008-11-25 08:24:15 +00:00
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.print_header = bts_trace_print_header,
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.print_line = bts_trace_print_line,
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.start = bts_trace_start,
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.stop = bts_trace_stop,
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2009-01-19 09:33:31 +00:00
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.open = trace_bts_prepare,
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2009-03-13 09:50:27 +00:00
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.close = trace_bts_close,
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#ifdef CONFIG_FTRACE_SELFTEST
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.selftest = trace_selftest_startup_hw_branches,
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#endif /* CONFIG_FTRACE_SELFTEST */
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2008-11-25 08:24:15 +00:00
|
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};
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__init static int init_bts_trace(void)
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{
|
2009-02-24 12:55:18 +00:00
|
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register_hotcpu_notifier(&bts_hotcpu_notifier);
|
2008-11-25 08:24:15 +00:00
|
|
|
return register_tracer(&bts_tracer);
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|
|
|
}
|
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device_initcall(init_bts_trace);
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