83 lines
1.7 KiB
C
83 lines
1.7 KiB
C
/*
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*
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* Function return tracer.
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* Copyright (c) 2008 Frederic Weisbecker <fweisbec@gmail.com>
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* Mostly borrowed from function tracer which
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* is Copyright (c) Steven Rostedt <srostedt@redhat.com>
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*
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*/
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#include <linux/debugfs.h>
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#include <linux/uaccess.h>
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#include <linux/ftrace.h>
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#include <linux/fs.h>
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#include "trace.h"
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static void start_return_trace(struct trace_array *tr)
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{
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register_ftrace_return(&trace_function_return);
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}
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static void stop_return_trace(struct trace_array *tr)
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{
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unregister_ftrace_return();
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}
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static void return_trace_init(struct trace_array *tr)
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{
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int cpu;
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for_each_online_cpu(cpu)
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tracing_reset(tr, cpu);
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start_return_trace(tr);
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}
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static void return_trace_reset(struct trace_array *tr)
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{
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stop_return_trace(tr);
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}
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enum print_line_t
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print_return_function(struct trace_iterator *iter)
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{
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struct trace_seq *s = &iter->seq;
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struct trace_entry *entry = iter->ent;
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struct ftrace_ret_entry *field;
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int ret;
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if (entry->type == TRACE_FN_RET) {
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trace_assign_type(field, entry);
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ret = trace_seq_printf(s, "%pF -> ", (void *)field->parent_ip);
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if (!ret)
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return TRACE_TYPE_PARTIAL_LINE;
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ret = seq_print_ip_sym(s, field->ip,
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trace_flags & TRACE_ITER_SYM_MASK);
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if (!ret)
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return TRACE_TYPE_PARTIAL_LINE;
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ret = trace_seq_printf(s, " (%llu ns)\n",
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field->rettime - field->calltime);
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if (!ret)
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return TRACE_TYPE_PARTIAL_LINE;
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else
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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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static struct tracer return_trace __read_mostly =
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{
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.name = "return",
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.init = return_trace_init,
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.reset = return_trace_reset,
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.print_line = print_return_function
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};
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static __init int init_return_trace(void)
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{
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return register_tracer(&return_trace);
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}
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device_initcall(init_return_trace);
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