// SPDX-License-Identifier: GPL-2.0
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/*
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*
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* Function graph tracer.
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* Copyright (c) 2008-2009 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/uaccess.h>
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#include <linux/ftrace.h>
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#include <linux/interrupt.h>
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#include <linux/slab.h>
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#include <linux/fs.h>
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#include "trace.h"
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#include "trace_output.h"
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/* When set, irq functions will be ignored */
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static int ftrace_graph_skip_irqs;
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struct fgraph_cpu_data {
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pid_t last_pid;
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int depth;
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int depth_irq;
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int ignore;
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unsigned long enter_funcs[FTRACE_RETFUNC_DEPTH];
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};
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struct fgraph_data {
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struct fgraph_cpu_data __percpu *cpu_data;
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/* Place to preserve last processed entry. */
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struct ftrace_graph_ent_entry ent;
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struct ftrace_graph_ret_entry ret;
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int failed;
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int cpu;
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};
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#define TRACE_GRAPH_INDENT 2
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unsigned int fgraph_max_depth;
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static struct tracer_opt trace_opts[] = {
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/* Display overruns? (for self-debug purpose) */
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{ TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
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/* Display CPU ? */
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{ TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
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/* Display Overhead ? */
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{ TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
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/* Display proc name/pid */
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{ TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
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/* Display duration of execution */
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{ TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
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/* Display absolute time of an entry */
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{ TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
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/* Display interrupts */
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{ TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) },
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/* Display function name after trailing } */
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{ TRACER_OPT(funcgraph-tail, TRACE_GRAPH_PRINT_TAIL) },
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/* Include sleep time (scheduled out) between entry and return */
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{ TRACER_OPT(sleep-time, TRACE_GRAPH_SLEEP_TIME) },
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#ifdef CONFIG_FUNCTION_PROFILER
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/* Include time within nested functions */
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{ TRACER_OPT(graph-time, TRACE_GRAPH_GRAPH_TIME) },
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#endif
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{ } /* Empty entry */
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};
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static struct tracer_flags tracer_flags = {
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/* Don't display overruns, proc, or tail by default */
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.val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
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TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS |
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TRACE_GRAPH_SLEEP_TIME | TRACE_GRAPH_GRAPH_TIME,
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.opts = trace_opts
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};
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static struct trace_array *graph_array;
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/*
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* DURATION column is being also used to display IRQ signs,
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* following values are used by print_graph_irq and others
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* to fill in space into DURATION column.
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*/
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enum {
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FLAGS_FILL_FULL = 1 << TRACE_GRAPH_PRINT_FILL_SHIFT,
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FLAGS_FILL_START = 2 << TRACE_GRAPH_PRINT_FILL_SHIFT,
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FLAGS_FILL_END = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT,
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};
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static void
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print_graph_duration(struct trace_array *tr, unsigned long long duration,
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struct trace_seq *s, u32 flags);
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int __trace_graph_entry(struct trace_array *tr,
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struct ftrace_graph_ent *trace,
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unsigned int trace_ctx)
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{
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struct trace_event_call *call = &event_funcgraph_entry;
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struct ring_buffer_event *event;
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struct trace_buffer *buffer = tr->array_buffer.buffer;
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struct ftrace_graph_ent_entry *entry;
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event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
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sizeof(*entry), trace_ctx);
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if (!event)
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return 0;
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entry = ring_buffer_event_data(event);
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entry->graph_ent = *trace;
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if (!call_filter_check_discard(call, entry, buffer, event))
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trace_buffer_unlock_commit_nostack(buffer, event);
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return 1;
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}
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static inline int ftrace_graph_ignore_irqs(void)
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{
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if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))
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return 0;
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return in_irq();
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}
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int trace_graph_entry(struct ftrace_graph_ent *trace)
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{
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struct trace_array *tr = graph_array;
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struct trace_array_cpu *data;
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unsigned long flags;
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unsigned int trace_ctx;
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long disabled;
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int ret;
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int cpu;
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if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT))
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return 0;
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/*
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* Do not trace a function if it's filtered by set_graph_notrace.
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* Make the index of ret stack negative to indicate that it should
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* ignore further functions. But it needs its own ret stack entry
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* to recover the original index in order to continue tracing after
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* returning from the function.
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*/
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if (ftrace_graph_notrace_addr(trace->func)) {
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trace_recursion_set(TRACE_GRAPH_NOTRACE_BIT);
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/*
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* Need to return 1 to have the return called
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* that will clear the NOTRACE bit.
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*/
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return 1;
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}
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if (!ftrace_trace_task(tr))
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return 0;
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if (ftrace_graph_ignore_func(trace))
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return 0;
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if (ftrace_graph_ignore_irqs())
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return 0;
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/*
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* Stop here if tracing_threshold is set. We only write function return
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* events to the ring buffer.
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*/
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if (tracing_thresh)
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return 1;
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local_irq_save(flags);
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cpu = raw_smp_processor_id();
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data = per_cpu_ptr(tr->array_buffer.data, cpu);
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disabled = atomic_inc_return(&data->disabled);
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if (likely(disabled == 1)) {
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trace_ctx = tracing_gen_ctx_flags(flags);
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ret = __trace_graph_entry(tr, trace, trace_ctx);
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} else {
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ret = 0;
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}
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atomic_dec(&data->disabled);
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local_irq_restore(flags);
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return ret;
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}
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static void
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__trace_graph_function(struct trace_array *tr,
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unsigned long ip, unsigned int trace_ctx)
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{
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u64 time = trace_clock_local();
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struct ftrace_graph_ent ent = {
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.func = ip,
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.depth = 0,
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};
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struct ftrace_graph_ret ret = {
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.func = ip,
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.depth = 0,
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.calltime = time,
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.rettime = time,
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};
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__trace_graph_entry(tr, &ent, trace_ctx);
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__trace_graph_return(tr, &ret, trace_ctx);
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}
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void
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trace_graph_function(struct trace_array *tr,
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unsigned long ip, unsigned long parent_ip,
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unsigned int trace_ctx)
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{
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__trace_graph_function(tr, ip, trace_ctx);
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}
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void __trace_graph_return(struct trace_array *tr,
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struct ftrace_graph_ret *trace,
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unsigned int trace_ctx)
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{
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struct trace_event_call *call = &event_funcgraph_exit;
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struct ring_buffer_event *event;
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struct trace_buffer *buffer = tr->array_buffer.buffer;
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struct ftrace_graph_ret_entry *entry;
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event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
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sizeof(*entry), trace_ctx);
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if (!event)
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return;
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entry = ring_buffer_event_data(event);
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entry->ret = *trace;
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if (!call_filter_check_discard(call, entry, buffer, event))
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trace_buffer_unlock_commit_nostack(buffer, event);
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}
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void trace_graph_return(struct ftrace_graph_ret *trace)
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{
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struct trace_array *tr = graph_array;
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struct trace_array_cpu *data;
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unsigned long flags;
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unsigned int trace_ctx;
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long disabled;
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int cpu;
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ftrace_graph_addr_finish(trace);
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if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
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trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
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return;
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}
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local_irq_save(flags);
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cpu = raw_smp_processor_id();
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data = per_cpu_ptr(tr->array_buffer.data, cpu);
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disabled = atomic_inc_return(&data->disabled);
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if (likely(disabled == 1)) {
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trace_ctx = tracing_gen_ctx_flags(flags);
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__trace_graph_return(tr, trace, trace_ctx);
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}
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atomic_dec(&data->disabled);
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local_irq_restore(flags);
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}
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void set_graph_array(struct trace_array *tr)
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{
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graph_array = tr;
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/* Make graph_array visible before we start tracing */
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smp_mb();
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}
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static void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
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{
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ftrace_graph_addr_finish(trace);
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if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
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trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
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return;
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}
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if (tracing_thresh &&
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(trace->rettime - trace->calltime < tracing_thresh))
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return;
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else
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trace_graph_return(trace);
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}
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static struct fgraph_ops funcgraph_thresh_ops = {
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.entryfunc = &trace_graph_entry,
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.retfunc = &trace_graph_thresh_return,
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};
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static struct fgraph_ops funcgraph_ops = {
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.entryfunc = &trace_graph_entry,
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.retfunc = &trace_graph_return,
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};
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static int graph_trace_init(struct trace_array *tr)
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{
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int ret;
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set_graph_array(tr);
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if (tracing_thresh)
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ret = register_ftrace_graph(&funcgraph_thresh_ops);
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else
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ret = register_ftrace_graph(&funcgraph_ops);
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if (ret)
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return ret;
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tracing_start_cmdline_record();
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return 0;
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}
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static void graph_trace_reset(struct trace_array *tr)
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{
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tracing_stop_cmdline_record();
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if (tracing_thresh)
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unregister_ftrace_graph(&funcgraph_thresh_ops);
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else
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unregister_ftrace_graph(&funcgraph_ops);
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}
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static int graph_trace_update_thresh(struct trace_array *tr)
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{
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graph_trace_reset(tr);
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return graph_trace_init(tr);
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}
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static int max_bytes_for_cpu;
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static void print_graph_cpu(struct trace_seq *s, int cpu)
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{
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/*
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* Start with a space character - to make it stand out
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* to the right a bit when trace output is pasted into
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* email:
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*/
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trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
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}
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#define TRACE_GRAPH_PROCINFO_LENGTH 14
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static void print_graph_proc(struct trace_seq *s, pid_t pid)
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{
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char comm[TASK_COMM_LEN];
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/* sign + log10(MAX_INT) + '\0' */
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char pid_str[11];
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int spaces = 0;
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int len;
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int i;
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trace_find_cmdline(pid, comm);
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comm[7] = '\0';
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sprintf(pid_str, "%d", pid);
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/* 1 stands for the "-" character */
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len = strlen(comm) + strlen(pid_str) + 1;
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if (len < TRACE_GRAPH_PROCINFO_LENGTH)
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spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
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/* First spaces to align center */
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for (i = 0; i < spaces / 2; i++)
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trace_seq_putc(s, ' ');
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trace_seq_printf(s, "%s-%s", comm, pid_str);
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/* Last spaces to align center */
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for (i = 0; i < spaces - (spaces / 2); i++)
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trace_seq_putc(s, ' ');
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}
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static void print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
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{
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trace_seq_putc(s, ' ');
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trace_print_lat_fmt(s, entry);
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trace_seq_puts(s, " | ");
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}
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/* If the pid changed since the last trace, output this event */
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static void
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verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
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{
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pid_t prev_pid;
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pid_t *last_pid;
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if (!data)
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return;
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last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
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if (*last_pid == pid)
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return;
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prev_pid = *last_pid;
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*last_pid = pid;
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if (prev_pid == -1)
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return;
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/*
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* Context-switch trace line:
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------------------------------------------
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| 1) migration/0--1 => sshd-1755
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------------------------------------------
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*/
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trace_seq_puts(s, " ------------------------------------------\n");
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print_graph_cpu(s, cpu);
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print_graph_proc(s, prev_pid);
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trace_seq_puts(s, " => ");
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print_graph_proc(s, pid);
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trace_seq_puts(s, "\n ------------------------------------------\n\n");
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}
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static struct ftrace_graph_ret_entry *
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get_return_for_leaf(struct trace_iterator *iter,
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struct ftrace_graph_ent_entry *curr)
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{
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struct fgraph_data *data = iter->private;
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struct ring_buffer_iter *ring_iter = NULL;
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struct ring_buffer_event *event;
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struct ftrace_graph_ret_entry *next;
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/*
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* If the previous output failed to write to the seq buffer,
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* then we just reuse the data from before.
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*/
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if (data && data->failed) {
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curr = &data->ent;
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next = &data->ret;
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} else {
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ring_iter = trace_buffer_iter(iter, iter->cpu);
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/* First peek to compare current entry and the next one */
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if (ring_iter)
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event = ring_buffer_iter_peek(ring_iter, NULL);
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else {
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/*
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* We need to consume the current entry to see
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* the next one.
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*/
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ring_buffer_consume(iter->array_buffer->buffer, iter->cpu,
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NULL, NULL);
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event = ring_buffer_peek(iter->array_buffer->buffer, iter->cpu,
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NULL, NULL);
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}
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if (!event)
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return NULL;
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next = ring_buffer_event_data(event);
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if (data) {
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/*
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* Save current and next entries for later reference
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* if the output fails.
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*/
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data->ent = *curr;
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/*
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* If the next event is not a return type, then
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* we only care about what type it is. Otherwise we can
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* safely copy the entire event.
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*/
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if (next->ent.type == TRACE_GRAPH_RET)
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data->ret = *next;
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else
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data->ret.ent.type = next->ent.type;
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}
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}
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if (next->ent.type != TRACE_GRAPH_RET)
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return NULL;
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if (curr->ent.pid != next->ent.pid ||
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curr->graph_ent.func != next->ret.func)
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return NULL;
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/* this is a leaf, now advance the iterator */
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if (ring_iter)
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ring_buffer_iter_advance(ring_iter);
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return next;
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}
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static void print_graph_abs_time(u64 t, struct trace_seq *s)
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{
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unsigned long usecs_rem;
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usecs_rem = do_div(t, NSEC_PER_SEC);
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usecs_rem /= 1000;
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trace_seq_printf(s, "%5lu.%06lu | ",
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(unsigned long)t, usecs_rem);
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}
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static void
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print_graph_rel_time(struct trace_iterator *iter, struct trace_seq *s)
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{
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unsigned long long usecs;
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usecs = iter->ts - iter->array_buffer->time_start;
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do_div(usecs, NSEC_PER_USEC);
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trace_seq_printf(s, "%9llu us | ", usecs);
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}
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static void
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print_graph_irq(struct trace_iterator *iter, unsigned long addr,
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enum trace_type type, int cpu, pid_t pid, u32 flags)
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{
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struct trace_array *tr = iter->tr;
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struct trace_seq *s = &iter->seq;
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struct trace_entry *ent = iter->ent;
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if (addr < (unsigned long)__irqentry_text_start ||
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addr >= (unsigned long)__irqentry_text_end)
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return;
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if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
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/* Absolute time */
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if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
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print_graph_abs_time(iter->ts, s);
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/* Relative time */
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if (flags & TRACE_GRAPH_PRINT_REL_TIME)
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print_graph_rel_time(iter, s);
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/* Cpu */
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if (flags & TRACE_GRAPH_PRINT_CPU)
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print_graph_cpu(s, cpu);
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/* Proc */
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if (flags & TRACE_GRAPH_PRINT_PROC) {
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print_graph_proc(s, pid);
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trace_seq_puts(s, " | ");
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}
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/* Latency format */
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if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
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print_graph_lat_fmt(s, ent);
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}
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/* No overhead */
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print_graph_duration(tr, 0, s, flags | FLAGS_FILL_START);
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if (type == TRACE_GRAPH_ENT)
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trace_seq_puts(s, "==========>");
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else
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trace_seq_puts(s, "<==========");
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print_graph_duration(tr, 0, s, flags | FLAGS_FILL_END);
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trace_seq_putc(s, '\n');
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}
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void
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trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
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{
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unsigned long nsecs_rem = do_div(duration, 1000);
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/* log10(ULONG_MAX) + '\0' */
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char usecs_str[21];
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char nsecs_str[5];
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int len;
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int i;
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sprintf(usecs_str, "%lu", (unsigned long) duration);
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/* Print msecs */
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trace_seq_printf(s, "%s", usecs_str);
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len = strlen(usecs_str);
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/* Print nsecs (we don't want to exceed 7 numbers) */
|
if (len < 7) {
|
size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
|
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snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
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trace_seq_printf(s, ".%s", nsecs_str);
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len += strlen(nsecs_str) + 1;
|
}
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trace_seq_puts(s, " us ");
|
|
/* Print remaining spaces to fit the row's width */
|
for (i = len; i < 8; i++)
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trace_seq_putc(s, ' ');
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}
|
|
static void
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print_graph_duration(struct trace_array *tr, unsigned long long duration,
|
struct trace_seq *s, u32 flags)
|
{
|
if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
|
!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
|
return;
|
|
/* No real adata, just filling the column with spaces */
|
switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
|
case FLAGS_FILL_FULL:
|
trace_seq_puts(s, " | ");
|
return;
|
case FLAGS_FILL_START:
|
trace_seq_puts(s, " ");
|
return;
|
case FLAGS_FILL_END:
|
trace_seq_puts(s, " |");
|
return;
|
}
|
|
/* Signal a overhead of time execution to the output */
|
if (flags & TRACE_GRAPH_PRINT_OVERHEAD)
|
trace_seq_printf(s, "%c ", trace_find_mark(duration));
|
else
|
trace_seq_puts(s, " ");
|
|
trace_print_graph_duration(duration, s);
|
trace_seq_puts(s, "| ");
|
}
|
|
/* Case of a leaf function on its call entry */
|
static enum print_line_t
|
print_graph_entry_leaf(struct trace_iterator *iter,
|
struct ftrace_graph_ent_entry *entry,
|
struct ftrace_graph_ret_entry *ret_entry,
|
struct trace_seq *s, u32 flags)
|
{
|
struct fgraph_data *data = iter->private;
|
struct trace_array *tr = iter->tr;
|
struct ftrace_graph_ret *graph_ret;
|
struct ftrace_graph_ent *call;
|
unsigned long long duration;
|
int cpu = iter->cpu;
|
int i;
|
|
graph_ret = &ret_entry->ret;
|
call = &entry->graph_ent;
|
duration = graph_ret->rettime - graph_ret->calltime;
|
|
if (data) {
|
struct fgraph_cpu_data *cpu_data;
|
|
cpu_data = per_cpu_ptr(data->cpu_data, cpu);
|
|
/*
|
* Comments display at + 1 to depth. Since
|
* this is a leaf function, keep the comments
|
* equal to this depth.
|
*/
|
cpu_data->depth = call->depth - 1;
|
|
/* No need to keep this function around for this depth */
|
if (call->depth < FTRACE_RETFUNC_DEPTH &&
|
!WARN_ON_ONCE(call->depth < 0))
|
cpu_data->enter_funcs[call->depth] = 0;
|
}
|
|
/* Overhead and duration */
|
print_graph_duration(tr, duration, s, flags);
|
|
/* Function */
|
for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
|
trace_seq_putc(s, ' ');
|
|
trace_seq_printf(s, "%ps();\n", (void *)call->func);
|
|
print_graph_irq(iter, graph_ret->func, TRACE_GRAPH_RET,
|
cpu, iter->ent->pid, flags);
|
|
return trace_handle_return(s);
|
}
|
|
static enum print_line_t
|
print_graph_entry_nested(struct trace_iterator *iter,
|
struct ftrace_graph_ent_entry *entry,
|
struct trace_seq *s, int cpu, u32 flags)
|
{
|
struct ftrace_graph_ent *call = &entry->graph_ent;
|
struct fgraph_data *data = iter->private;
|
struct trace_array *tr = iter->tr;
|
int i;
|
|
if (data) {
|
struct fgraph_cpu_data *cpu_data;
|
int cpu = iter->cpu;
|
|
cpu_data = per_cpu_ptr(data->cpu_data, cpu);
|
cpu_data->depth = call->depth;
|
|
/* Save this function pointer to see if the exit matches */
|
if (call->depth < FTRACE_RETFUNC_DEPTH &&
|
!WARN_ON_ONCE(call->depth < 0))
|
cpu_data->enter_funcs[call->depth] = call->func;
|
}
|
|
/* No time */
|
print_graph_duration(tr, 0, s, flags | FLAGS_FILL_FULL);
|
|
/* Function */
|
for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
|
trace_seq_putc(s, ' ');
|
|
trace_seq_printf(s, "%ps() {\n", (void *)call->func);
|
|
if (trace_seq_has_overflowed(s))
|
return TRACE_TYPE_PARTIAL_LINE;
|
|
/*
|
* we already consumed the current entry to check the next one
|
* and see if this is a leaf.
|
*/
|
return TRACE_TYPE_NO_CONSUME;
|
}
|
|
static void
|
print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
|
int type, unsigned long addr, u32 flags)
|
{
|
struct fgraph_data *data = iter->private;
|
struct trace_entry *ent = iter->ent;
|
struct trace_array *tr = iter->tr;
|
int cpu = iter->cpu;
|
|
/* Pid */
|
verif_pid(s, ent->pid, cpu, data);
|
|
if (type)
|
/* Interrupt */
|
print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
|
|
if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
|
return;
|
|
/* Absolute time */
|
if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
|
print_graph_abs_time(iter->ts, s);
|
|
/* Relative time */
|
if (flags & TRACE_GRAPH_PRINT_REL_TIME)
|
print_graph_rel_time(iter, s);
|
|
/* Cpu */
|
if (flags & TRACE_GRAPH_PRINT_CPU)
|
print_graph_cpu(s, cpu);
|
|
/* Proc */
|
if (flags & TRACE_GRAPH_PRINT_PROC) {
|
print_graph_proc(s, ent->pid);
|
trace_seq_puts(s, " | ");
|
}
|
|
/* Latency format */
|
if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
|
print_graph_lat_fmt(s, ent);
|
|
return;
|
}
|
|
/*
|
* Entry check for irq code
|
*
|
* returns 1 if
|
* - we are inside irq code
|
* - we just entered irq code
|
*
|
* retunns 0 if
|
* - funcgraph-interrupts option is set
|
* - we are not inside irq code
|
*/
|
static int
|
check_irq_entry(struct trace_iterator *iter, u32 flags,
|
unsigned long addr, int depth)
|
{
|
int cpu = iter->cpu;
|
int *depth_irq;
|
struct fgraph_data *data = iter->private;
|
|
/*
|
* If we are either displaying irqs, or we got called as
|
* a graph event and private data does not exist,
|
* then we bypass the irq check.
|
*/
|
if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
|
(!data))
|
return 0;
|
|
depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
|
|
/*
|
* We are inside the irq code
|
*/
|
if (*depth_irq >= 0)
|
return 1;
|
|
if ((addr < (unsigned long)__irqentry_text_start) ||
|
(addr >= (unsigned long)__irqentry_text_end))
|
return 0;
|
|
/*
|
* We are entering irq code.
|
*/
|
*depth_irq = depth;
|
return 1;
|
}
|
|
/*
|
* Return check for irq code
|
*
|
* returns 1 if
|
* - we are inside irq code
|
* - we just left irq code
|
*
|
* returns 0 if
|
* - funcgraph-interrupts option is set
|
* - we are not inside irq code
|
*/
|
static int
|
check_irq_return(struct trace_iterator *iter, u32 flags, int depth)
|
{
|
int cpu = iter->cpu;
|
int *depth_irq;
|
struct fgraph_data *data = iter->private;
|
|
/*
|
* If we are either displaying irqs, or we got called as
|
* a graph event and private data does not exist,
|
* then we bypass the irq check.
|
*/
|
if ((flags & TRACE_GRAPH_PRINT_IRQS) ||
|
(!data))
|
return 0;
|
|
depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
|
|
/*
|
* We are not inside the irq code.
|
*/
|
if (*depth_irq == -1)
|
return 0;
|
|
/*
|
* We are inside the irq code, and this is returning entry.
|
* Let's not trace it and clear the entry depth, since
|
* we are out of irq code.
|
*
|
* This condition ensures that we 'leave the irq code' once
|
* we are out of the entry depth. Thus protecting us from
|
* the RETURN entry loss.
|
*/
|
if (*depth_irq >= depth) {
|
*depth_irq = -1;
|
return 1;
|
}
|
|
/*
|
* We are inside the irq code, and this is not the entry.
|
*/
|
return 1;
|
}
|
|
static enum print_line_t
|
print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
|
struct trace_iterator *iter, u32 flags)
|
{
|
struct fgraph_data *data = iter->private;
|
struct ftrace_graph_ent *call = &field->graph_ent;
|
struct ftrace_graph_ret_entry *leaf_ret;
|
static enum print_line_t ret;
|
int cpu = iter->cpu;
|
|
if (check_irq_entry(iter, flags, call->func, call->depth))
|
return TRACE_TYPE_HANDLED;
|
|
print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags);
|
|
leaf_ret = get_return_for_leaf(iter, field);
|
if (leaf_ret)
|
ret = print_graph_entry_leaf(iter, field, leaf_ret, s, flags);
|
else
|
ret = print_graph_entry_nested(iter, field, s, cpu, flags);
|
|
if (data) {
|
/*
|
* If we failed to write our output, then we need to make
|
* note of it. Because we already consumed our entry.
|
*/
|
if (s->full) {
|
data->failed = 1;
|
data->cpu = cpu;
|
} else
|
data->failed = 0;
|
}
|
|
return ret;
|
}
|
|
static enum print_line_t
|
print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
|
struct trace_entry *ent, struct trace_iterator *iter,
|
u32 flags)
|
{
|
unsigned long long duration = trace->rettime - trace->calltime;
|
struct fgraph_data *data = iter->private;
|
struct trace_array *tr = iter->tr;
|
pid_t pid = ent->pid;
|
int cpu = iter->cpu;
|
int func_match = 1;
|
int i;
|
|
if (check_irq_return(iter, flags, trace->depth))
|
return TRACE_TYPE_HANDLED;
|
|
if (data) {
|
struct fgraph_cpu_data *cpu_data;
|
int cpu = iter->cpu;
|
|
cpu_data = per_cpu_ptr(data->cpu_data, cpu);
|
|
/*
|
* Comments display at + 1 to depth. This is the
|
* return from a function, we now want the comments
|
* to display at the same level of the bracket.
|
*/
|
cpu_data->depth = trace->depth - 1;
|
|
if (trace->depth < FTRACE_RETFUNC_DEPTH &&
|
!WARN_ON_ONCE(trace->depth < 0)) {
|
if (cpu_data->enter_funcs[trace->depth] != trace->func)
|
func_match = 0;
|
cpu_data->enter_funcs[trace->depth] = 0;
|
}
|
}
|
|
print_graph_prologue(iter, s, 0, 0, flags);
|
|
/* Overhead and duration */
|
print_graph_duration(tr, duration, s, flags);
|
|
/* Closing brace */
|
for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++)
|
trace_seq_putc(s, ' ');
|
|
/*
|
* If the return function does not have a matching entry,
|
* then the entry was lost. Instead of just printing
|
* the '}' and letting the user guess what function this
|
* belongs to, write out the function name. Always do
|
* that if the funcgraph-tail option is enabled.
|
*/
|
if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL))
|
trace_seq_puts(s, "}\n");
|
else
|
trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
|
|
/* Overrun */
|
if (flags & TRACE_GRAPH_PRINT_OVERRUN)
|
trace_seq_printf(s, " (Overruns: %lu)\n",
|
trace->overrun);
|
|
print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
|
cpu, pid, flags);
|
|
return trace_handle_return(s);
|
}
|
|
static enum print_line_t
|
print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
|
struct trace_iterator *iter, u32 flags)
|
{
|
struct trace_array *tr = iter->tr;
|
unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
|
struct fgraph_data *data = iter->private;
|
struct trace_event *event;
|
int depth = 0;
|
int ret;
|
int i;
|
|
if (data)
|
depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
|
|
print_graph_prologue(iter, s, 0, 0, flags);
|
|
/* No time */
|
print_graph_duration(tr, 0, s, flags | FLAGS_FILL_FULL);
|
|
/* Indentation */
|
if (depth > 0)
|
for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++)
|
trace_seq_putc(s, ' ');
|
|
/* The comment */
|
trace_seq_puts(s, "/* ");
|
|
switch (iter->ent->type) {
|
case TRACE_BPUTS:
|
ret = trace_print_bputs_msg_only(iter);
|
if (ret != TRACE_TYPE_HANDLED)
|
return ret;
|
break;
|
case TRACE_BPRINT:
|
ret = trace_print_bprintk_msg_only(iter);
|
if (ret != TRACE_TYPE_HANDLED)
|
return ret;
|
break;
|
case TRACE_PRINT:
|
ret = trace_print_printk_msg_only(iter);
|
if (ret != TRACE_TYPE_HANDLED)
|
return ret;
|
break;
|
default:
|
event = ftrace_find_event(ent->type);
|
if (!event)
|
return TRACE_TYPE_UNHANDLED;
|
|
ret = event->funcs->trace(iter, sym_flags, event);
|
if (ret != TRACE_TYPE_HANDLED)
|
return ret;
|
}
|
|
if (trace_seq_has_overflowed(s))
|
goto out;
|
|
/* Strip ending newline */
|
if (s->buffer[s->seq.len - 1] == '\n') {
|
s->buffer[s->seq.len - 1] = '\0';
|
s->seq.len--;
|
}
|
|
trace_seq_puts(s, " */\n");
|
out:
|
return trace_handle_return(s);
|
}
|
|
|
enum print_line_t
|
print_graph_function_flags(struct trace_iterator *iter, u32 flags)
|
{
|
struct ftrace_graph_ent_entry *field;
|
struct fgraph_data *data = iter->private;
|
struct trace_entry *entry = iter->ent;
|
struct trace_seq *s = &iter->seq;
|
int cpu = iter->cpu;
|
int ret;
|
|
if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
|
per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
|
return TRACE_TYPE_HANDLED;
|
}
|
|
/*
|
* If the last output failed, there's a possibility we need
|
* to print out the missing entry which would never go out.
|
*/
|
if (data && data->failed) {
|
field = &data->ent;
|
iter->cpu = data->cpu;
|
ret = print_graph_entry(field, s, iter, flags);
|
if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
|
per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
|
ret = TRACE_TYPE_NO_CONSUME;
|
}
|
iter->cpu = cpu;
|
return ret;
|
}
|
|
switch (entry->type) {
|
case TRACE_GRAPH_ENT: {
|
/*
|
* print_graph_entry() may consume the current event,
|
* thus @field may become invalid, so we need to save it.
|
* sizeof(struct ftrace_graph_ent_entry) is very small,
|
* it can be safely saved at the stack.
|
*/
|
struct ftrace_graph_ent_entry saved;
|
trace_assign_type(field, entry);
|
saved = *field;
|
return print_graph_entry(&saved, s, iter, flags);
|
}
|
case TRACE_GRAPH_RET: {
|
struct ftrace_graph_ret_entry *field;
|
trace_assign_type(field, entry);
|
return print_graph_return(&field->ret, s, entry, iter, flags);
|
}
|
case TRACE_STACK:
|
case TRACE_FN:
|
/* dont trace stack and functions as comments */
|
return TRACE_TYPE_UNHANDLED;
|
|
default:
|
return print_graph_comment(s, entry, iter, flags);
|
}
|
|
return TRACE_TYPE_HANDLED;
|
}
|
|
static enum print_line_t
|
print_graph_function(struct trace_iterator *iter)
|
{
|
return print_graph_function_flags(iter, tracer_flags.val);
|
}
|
|
static enum print_line_t
|
print_graph_function_event(struct trace_iterator *iter, int flags,
|
struct trace_event *event)
|
{
|
return print_graph_function(iter);
|
}
|
|
static void print_lat_header(struct seq_file *s, u32 flags)
|
{
|
static const char spaces[] = " " /* 16 spaces */
|
" " /* 4 spaces */
|
" "; /* 17 spaces */
|
int size = 0;
|
|
if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
|
size += 16;
|
if (flags & TRACE_GRAPH_PRINT_REL_TIME)
|
size += 16;
|
if (flags & TRACE_GRAPH_PRINT_CPU)
|
size += 4;
|
if (flags & TRACE_GRAPH_PRINT_PROC)
|
size += 17;
|
|
seq_printf(s, "#%.*s _-----=> irqs-off \n", size, spaces);
|
seq_printf(s, "#%.*s / _----=> need-resched \n", size, spaces);
|
seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
|
seq_printf(s, "#%.*s|| / _--=> preempt-depth \n", size, spaces);
|
seq_printf(s, "#%.*s||| / \n", size, spaces);
|
}
|
|
static void __print_graph_headers_flags(struct trace_array *tr,
|
struct seq_file *s, u32 flags)
|
{
|
int lat = tr->trace_flags & TRACE_ITER_LATENCY_FMT;
|
|
if (lat)
|
print_lat_header(s, flags);
|
|
/* 1st line */
|
seq_putc(s, '#');
|
if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
|
seq_puts(s, " TIME ");
|
if (flags & TRACE_GRAPH_PRINT_REL_TIME)
|
seq_puts(s, " REL TIME ");
|
if (flags & TRACE_GRAPH_PRINT_CPU)
|
seq_puts(s, " CPU");
|
if (flags & TRACE_GRAPH_PRINT_PROC)
|
seq_puts(s, " TASK/PID ");
|
if (lat)
|
seq_puts(s, "|||| ");
|
if (flags & TRACE_GRAPH_PRINT_DURATION)
|
seq_puts(s, " DURATION ");
|
seq_puts(s, " FUNCTION CALLS\n");
|
|
/* 2nd line */
|
seq_putc(s, '#');
|
if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
|
seq_puts(s, " | ");
|
if (flags & TRACE_GRAPH_PRINT_REL_TIME)
|
seq_puts(s, " | ");
|
if (flags & TRACE_GRAPH_PRINT_CPU)
|
seq_puts(s, " | ");
|
if (flags & TRACE_GRAPH_PRINT_PROC)
|
seq_puts(s, " | | ");
|
if (lat)
|
seq_puts(s, "|||| ");
|
if (flags & TRACE_GRAPH_PRINT_DURATION)
|
seq_puts(s, " | | ");
|
seq_puts(s, " | | | |\n");
|
}
|
|
static void print_graph_headers(struct seq_file *s)
|
{
|
print_graph_headers_flags(s, tracer_flags.val);
|
}
|
|
void print_graph_headers_flags(struct seq_file *s, u32 flags)
|
{
|
struct trace_iterator *iter = s->private;
|
struct trace_array *tr = iter->tr;
|
|
if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
|
return;
|
|
if (tr->trace_flags & TRACE_ITER_LATENCY_FMT) {
|
/* print nothing if the buffers are empty */
|
if (trace_empty(iter))
|
return;
|
|
print_trace_header(s, iter);
|
}
|
|
__print_graph_headers_flags(tr, s, flags);
|
}
|
|
void graph_trace_open(struct trace_iterator *iter)
|
{
|
/* pid and depth on the last trace processed */
|
struct fgraph_data *data;
|
gfp_t gfpflags;
|
int cpu;
|
|
iter->private = NULL;
|
|
/* We can be called in atomic context via ftrace_dump() */
|
gfpflags = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;
|
|
data = kzalloc(sizeof(*data), gfpflags);
|
if (!data)
|
goto out_err;
|
|
data->cpu_data = alloc_percpu_gfp(struct fgraph_cpu_data, gfpflags);
|
if (!data->cpu_data)
|
goto out_err_free;
|
|
for_each_possible_cpu(cpu) {
|
pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
|
int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
|
int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
|
int *depth_irq = &(per_cpu_ptr(data->cpu_data, cpu)->depth_irq);
|
|
*pid = -1;
|
*depth = 0;
|
*ignore = 0;
|
*depth_irq = -1;
|
}
|
|
iter->private = data;
|
|
return;
|
|
out_err_free:
|
kfree(data);
|
out_err:
|
pr_warn("function graph tracer: not enough memory\n");
|
}
|
|
void graph_trace_close(struct trace_iterator *iter)
|
{
|
struct fgraph_data *data = iter->private;
|
|
if (data) {
|
free_percpu(data->cpu_data);
|
kfree(data);
|
}
|
}
|
|
static int
|
func_graph_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
|
{
|
if (bit == TRACE_GRAPH_PRINT_IRQS)
|
ftrace_graph_skip_irqs = !set;
|
|
if (bit == TRACE_GRAPH_SLEEP_TIME)
|
ftrace_graph_sleep_time_control(set);
|
|
if (bit == TRACE_GRAPH_GRAPH_TIME)
|
ftrace_graph_graph_time_control(set);
|
|
return 0;
|
}
|
|
static struct trace_event_functions graph_functions = {
|
.trace = print_graph_function_event,
|
};
|
|
static struct trace_event graph_trace_entry_event = {
|
.type = TRACE_GRAPH_ENT,
|
.funcs = &graph_functions,
|
};
|
|
static struct trace_event graph_trace_ret_event = {
|
.type = TRACE_GRAPH_RET,
|
.funcs = &graph_functions
|
};
|
|
static struct tracer graph_trace __tracer_data = {
|
.name = "function_graph",
|
.update_thresh = graph_trace_update_thresh,
|
.open = graph_trace_open,
|
.pipe_open = graph_trace_open,
|
.close = graph_trace_close,
|
.pipe_close = graph_trace_close,
|
.init = graph_trace_init,
|
.reset = graph_trace_reset,
|
.print_line = print_graph_function,
|
.print_header = print_graph_headers,
|
.flags = &tracer_flags,
|
.set_flag = func_graph_set_flag,
|
#ifdef CONFIG_FTRACE_SELFTEST
|
.selftest = trace_selftest_startup_function_graph,
|
#endif
|
};
|
|
|
static ssize_t
|
graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt,
|
loff_t *ppos)
|
{
|
unsigned long val;
|
int ret;
|
|
ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
|
if (ret)
|
return ret;
|
|
fgraph_max_depth = val;
|
|
*ppos += cnt;
|
|
return cnt;
|
}
|
|
static ssize_t
|
graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt,
|
loff_t *ppos)
|
{
|
char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/
|
int n;
|
|
n = sprintf(buf, "%d\n", fgraph_max_depth);
|
|
return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
|
}
|
|
static const struct file_operations graph_depth_fops = {
|
.open = tracing_open_generic,
|
.write = graph_depth_write,
|
.read = graph_depth_read,
|
.llseek = generic_file_llseek,
|
};
|
|
static __init int init_graph_tracefs(void)
|
{
|
int ret;
|
|
ret = tracing_init_dentry();
|
if (ret)
|
return 0;
|
|
trace_create_file("max_graph_depth", 0644, NULL,
|
NULL, &graph_depth_fops);
|
|
return 0;
|
}
|
fs_initcall(init_graph_tracefs);
|
|
static __init int init_graph_trace(void)
|
{
|
max_bytes_for_cpu = snprintf(NULL, 0, "%u", nr_cpu_ids - 1);
|
|
if (!register_trace_event(&graph_trace_entry_event)) {
|
pr_warn("Warning: could not register graph trace events\n");
|
return 1;
|
}
|
|
if (!register_trace_event(&graph_trace_ret_event)) {
|
pr_warn("Warning: could not register graph trace events\n");
|
return 1;
|
}
|
|
return register_tracer(&graph_trace);
|
}
|
|
core_initcall(init_graph_trace);
|
