5601020feb
After some initcall traces, some initcall names may be inconsistent. That's because these functions will disappear from the .init section and also their name from the symbols table. So we have to copy the name of the function in a buffer large enough during the trace appending. It is not costly for the ring_buffer because the number of initcall entries is commonly not really large. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
121 lines
2.7 KiB
C
121 lines
2.7 KiB
C
/*
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* ring buffer based initcalls tracer
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*
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* Copyright (C) 2008 Frederic Weisbecker <fweisbec@gmail.com>
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*
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*/
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#include <linux/init.h>
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#include <linux/debugfs.h>
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#include <linux/ftrace.h>
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#include <linux/kallsyms.h>
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#include "trace.h"
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static struct trace_array *boot_trace;
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static int trace_boot_enabled;
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/* Should be started after do_pre_smp_initcalls() in init/main.c */
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void start_boot_trace(void)
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{
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trace_boot_enabled = 1;
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}
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void stop_boot_trace(struct trace_array *tr)
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{
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trace_boot_enabled = 0;
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}
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static void boot_trace_init(struct trace_array *tr)
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{
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int cpu;
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boot_trace = tr;
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trace_boot_enabled = 0;
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for_each_cpu_mask(cpu, cpu_possible_map)
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tracing_reset(tr, cpu);
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}
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static void boot_trace_ctrl_update(struct trace_array *tr)
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{
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if (tr->ctrl)
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start_boot_trace();
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else
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stop_boot_trace(tr);
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}
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static enum print_line_t initcall_print_line(struct trace_iterator *iter)
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{
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int ret;
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struct trace_entry *entry = iter->ent;
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struct trace_boot *field = (struct trace_boot *)entry;
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struct boot_trace *it = &field->initcall;
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struct trace_seq *s = &iter->seq;
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struct timespec calltime = ktime_to_timespec(it->calltime);
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struct timespec rettime = ktime_to_timespec(it->rettime);
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if (entry->type == TRACE_BOOT) {
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ret = trace_seq_printf(s, "[%5ld.%06ld] calling %s @ %i\n",
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calltime.tv_sec,
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calltime.tv_nsec,
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it->func, it->caller);
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if (!ret)
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return TRACE_TYPE_PARTIAL_LINE;
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ret = trace_seq_printf(s, "[%5ld.%06ld] initcall %s "
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"returned %d after %lld msecs\n",
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rettime.tv_sec,
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rettime.tv_nsec,
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it->func, it->result, it->duration);
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if (!ret)
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return TRACE_TYPE_PARTIAL_LINE;
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return TRACE_TYPE_HANDLED;
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}
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return TRACE_TYPE_UNHANDLED;
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}
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struct tracer boot_tracer __read_mostly =
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{
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.name = "initcall",
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.init = boot_trace_init,
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.reset = stop_boot_trace,
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.ctrl_update = boot_trace_ctrl_update,
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.print_line = initcall_print_line,
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};
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void trace_boot(struct boot_trace *it, initcall_t fn)
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{
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struct ring_buffer_event *event;
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struct trace_boot *entry;
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struct trace_array_cpu *data;
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unsigned long irq_flags;
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struct trace_array *tr = boot_trace;
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if (!trace_boot_enabled)
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return;
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/* Get its name now since this function could
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* disappear because it is in the .init section.
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*/
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sprint_symbol(it->func, (unsigned long)fn);
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preempt_disable();
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data = tr->data[smp_processor_id()];
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event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
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&irq_flags);
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if (!event)
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goto out;
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entry = ring_buffer_event_data(event);
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tracing_generic_entry_update(&entry->ent, 0, 0);
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entry->ent.type = TRACE_BOOT;
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entry->initcall = *it;
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ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
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trace_wake_up();
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out:
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preempt_enable();
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}
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