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trace_functions_graph.c
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// SPDX-License-Identifier: GPL-2.0
/*
*
* Function graph tracer.
* Copyright (c) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>
* Mostly borrowed from function tracer which
* is Copyright (c) Steven Rostedt <srostedt@redhat.com>
*
*/
#include <linux/uaccess.h>
#include <linux/ftrace.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include "trace.h"
#include "trace_output.h"
/* When set, irq functions will be ignored */
static int ftrace_graph_skip_irqs;
struct fgraph_cpu_data {
pid_t last_pid;
int depth;
int depth_irq;
int ignore;
unsigned long enter_funcs[FTRACE_RETFUNC_DEPTH];
};
struct fgraph_data {
struct fgraph_cpu_data __percpu *cpu_data;
/* Place to preserve last processed entry. */
struct ftrace_graph_ent_entry ent;
struct ftrace_graph_ret_entry ret;
int failed;
int cpu;
};
#define TRACE_GRAPH_INDENT 2
unsigned int fgraph_max_depth;
static struct tracer_opt trace_opts[] = {
/* Display overruns? (for self-debug purpose) */
{ TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
/* Display CPU ? */
{ TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
/* Display Overhead ? */
{ TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
/* Display proc name/pid */
{ TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
/* Display duration of execution */
{ TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
/* Display absolute time of an entry */
{ TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
/* Display interrupts */
{ TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) },
/* Display function name after trailing } */
{ TRACER_OPT(funcgraph-tail, TRACE_GRAPH_PRINT_TAIL) },
/* Include sleep time (scheduled out) between entry and return */
{ TRACER_OPT(sleep-time, TRACE_GRAPH_SLEEP_TIME) },
/* Include time within nested functions */
{ TRACER_OPT(graph-time, TRACE_GRAPH_GRAPH_TIME) },
{ } /* Empty entry */
};
static struct tracer_flags tracer_flags = {
/* Don't display overruns, proc, or tail by default */
.val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS |
TRACE_GRAPH_SLEEP_TIME | TRACE_GRAPH_GRAPH_TIME,
.opts = trace_opts
};
static struct trace_array *graph_array;
/*
* DURATION column is being also used to display IRQ signs,
* following values are used by print_graph_irq and others
* to fill in space into DURATION column.
*/
enum {
FLAGS_FILL_FULL = 1 << TRACE_GRAPH_PRINT_FILL_SHIFT,
FLAGS_FILL_START = 2 << TRACE_GRAPH_PRINT_FILL_SHIFT,
FLAGS_FILL_END = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT,
};
static void
print_graph_duration(struct trace_array *tr, unsigned long long duration,
struct trace_seq *s, u32 flags);
/**
* ftrace_graph_ret_addr - convert a potentially modified stack return address
* to its original value
*
* This function can be called by stack unwinding code to convert a found stack
* return address ('ret') to its original value, in case the function graph
* tracer has modified it to be 'return_to_handler'. If the address hasn't
* been modified, the unchanged value of 'ret' is returned.
*
* 'idx' is a state variable which should be initialized by the caller to zero
* before the first call.
*
* 'retp' is a pointer to the return address on the stack. It's ignored if
* the arch doesn't have HAVE_FUNCTION_GRAPH_RET_ADDR_PTR defined.
*/
#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
unsigned long ret, unsigned long *retp)
{
int index = task->curr_ret_stack;
int i;
if (ret != (unsigned long)return_to_handler)
return ret;
if (index < 0)
return ret;
for (i = 0; i <= index; i++)
if (task->ret_stack[i].retp == retp)
return task->ret_stack[i].ret;
return ret;
}
#else /* !HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */
unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
unsigned long ret, unsigned long *retp)
{
int task_idx;
if (ret != (unsigned long)return_to_handler)
return ret;
task_idx = task->curr_ret_stack;
if (!task->ret_stack || task_idx < *idx)
return ret;
task_idx -= *idx;
(*idx)++;
return task->ret_stack[task_idx].ret;
}
#endif /* HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */
int __trace_graph_entry(struct trace_array *tr,
struct ftrace_graph_ent *trace,
unsigned long flags,
int pc)
{
struct trace_event_call *call = &event_funcgraph_entry;
struct ring_buffer_event *event;
struct ring_buffer *buffer = tr->trace_buffer.buffer;
struct ftrace_graph_ent_entry *entry;
event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
sizeof(*entry), flags, pc);
if (!event)
return 0;
entry = ring_buffer_event_data(event);
entry->graph_ent = *trace;
if (!call_filter_check_discard(call, entry, buffer, event))
trace_buffer_unlock_commit_nostack(buffer, event);
return 1;
}
static inline int ftrace_graph_ignore_irqs(void)
{
if (!ftrace_graph_skip_irqs || trace_recursion_test(TRACE_IRQ_BIT))
return 0;
return in_irq();
}
int trace_graph_entry(struct ftrace_graph_ent *trace)
{
struct trace_array *tr = graph_array;
struct trace_array_cpu *data;
unsigned long flags;
long disabled;
int ret;
int cpu;
int pc;
if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT))
return 0;
if (ftrace_graph_notrace_addr(trace->func)) {
trace_recursion_set(TRACE_GRAPH_NOTRACE_BIT);
/*
* Need to return 1 to have the return called
* that will clear the NOTRACE bit.
*/
return 1;
}
if (!ftrace_trace_task(tr))
return 0;
if (ftrace_graph_ignore_func(trace))
return 0;
if (ftrace_graph_ignore_irqs())
return 0;
/*
* Do not trace a function if it's filtered by set_graph_notrace.
* Make the index of ret stack negative to indicate that it should
* ignore further functions. But it needs its own ret stack entry
* to recover the original index in order to continue tracing after
* returning from the function.
*/
if (ftrace_graph_notrace_addr(trace->func))
return 1;
/*
* Stop here if tracing_threshold is set. We only write function return
* events to the ring buffer.
*/
if (tracing_thresh)
return 1;
local_irq_save(flags);
cpu = raw_smp_processor_id();
data = per_cpu_ptr(tr->trace_buffer.data, cpu);
disabled = atomic_inc_return(&data->disabled);
if (likely(disabled == 1)) {
pc = preempt_count();
ret = __trace_graph_entry(tr, trace, flags, pc);
} else {
ret = 0;
}
atomic_dec(&data->disabled);
local_irq_restore(flags);
return ret;
}
static void
__trace_graph_function(struct trace_array *tr,
unsigned long ip, unsigned long flags, int pc)
{
u64 time = trace_clock_local();
struct ftrace_graph_ent ent = {
.func = ip,
.depth = 0,
};
struct ftrace_graph_ret ret = {
.func = ip,
.depth = 0,
.calltime = time,
.rettime = time,
};
__trace_graph_entry(tr, &ent, flags, pc);
__trace_graph_return(tr, &ret, flags, pc);
}
void
trace_graph_function(struct trace_array *tr,
unsigned long ip, unsigned long parent_ip,
unsigned long flags, int pc)
{
__trace_graph_function(tr, ip, flags, pc);
}
void __trace_graph_return(struct trace_array *tr,
struct ftrace_graph_ret *trace,
unsigned long flags,
int pc)
{
struct trace_event_call *call = &event_funcgraph_exit;
struct ring_buffer_event *event;
struct ring_buffer *buffer = tr->trace_buffer.buffer;
struct ftrace_graph_ret_entry *entry;
event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
sizeof(*entry), flags, pc);
if (!event)
return;
entry = ring_buffer_event_data(event);
entry->ret = *trace;
if (!call_filter_check_discard(call, entry, buffer, event))
trace_buffer_unlock_commit_nostack(buffer, event);
}
void trace_graph_return(struct ftrace_graph_ret *trace)
{
struct trace_array *tr = graph_array;
struct trace_array_cpu *data;
unsigned long flags;
long disabled;
int cpu;
int pc;
ftrace_graph_addr_finish(trace);
if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
return;
}
local_irq_save(flags);
cpu = raw_smp_processor_id();
data = per_cpu_ptr(tr->trace_buffer.data, cpu);
disabled = atomic_inc_return(&data->disabled);
if (likely(disabled == 1)) {
pc = preempt_count();
__trace_graph_return(tr, trace, flags, pc);
}
atomic_dec(&data->disabled);
local_irq_restore(flags);
}
void set_graph_array(struct trace_array *tr)
{
graph_array = tr;
/* Make graph_array visible before we start tracing */
smp_mb();
}
static void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
{
ftrace_graph_addr_finish(trace);
if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
return;
}
if (tracing_thresh &&
(trace->rettime - trace->calltime < tracing_thresh))
return;
else
trace_graph_return(trace);
}
static int graph_trace_init(struct trace_array *tr)
{
int ret;
set_graph_array(tr);
if (tracing_thresh)
ret = register_ftrace_graph(&trace_graph_thresh_return,
&trace_graph_entry);
else
ret = register_ftrace_graph(&trace_graph_return,
&trace_graph_entry);
if (ret)
return ret;
tracing_start_cmdline_record();
return 0;
}
static void graph_trace_reset(struct trace_array *tr)
{
tracing_stop_cmdline_record();
unregister_ftrace_graph();
}
static int graph_trace_update_thresh(struct trace_array *tr)
{
graph_trace_reset(tr);
return graph_trace_init(tr);
}
static int max_bytes_for_cpu;
static void print_graph_cpu(struct trace_seq *s, int cpu)
{
/*
* Start with a space character - to make it stand out
* to the right a bit when trace output is pasted into
* email:
*/
trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
}
#define TRACE_GRAPH_PROCINFO_LENGTH 14
static void print_graph_proc(struct trace_seq *s, pid_t pid)
{
char comm[TASK_COMM_LEN];
/* sign + log10(MAX_INT) + '\0' */
char pid_str[11];
int spaces = 0;
int len;
int i;
trace_find_cmdline(pid, comm);
comm[7] = '\0';
sprintf(pid_str, "%d", pid);
/* 1 stands for the "-" character */
len = strlen(comm) + strlen(pid_str) + 1;
if (len < TRACE_GRAPH_PROCINFO_LENGTH)
spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
/* First spaces to align center */
for (i = 0; i < spaces / 2; i++)
trace_seq_putc(s, ' ');
trace_seq_printf(s, "%s-%s", comm, pid_str);
/* Last spaces to align center */
for (i = 0; i < spaces - (spaces / 2); i++)
trace_seq_putc(s, ' ');
}
static void print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
{
trace_seq_putc(s, ' ');
trace_print_lat_fmt(s, entry);
}
/* If the pid changed since the last trace, output this event */
static void
verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
{
pid_t prev_pid;
pid_t *last_pid;
if (!data)
return;
last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
if (*last_pid == pid)
return;
prev_pid = *last_pid;
*last_pid = pid;
if (prev_pid == -1)
return;
/*
* Context-switch trace line:
------------------------------------------
| 1) migration/0--1 => sshd-1755
------------------------------------------
*/
trace_seq_puts(s, " ------------------------------------------\n");
print_graph_cpu(s, cpu);
print_graph_proc(s, prev_pid);
trace_seq_puts(s, " => ");
print_graph_proc(s, pid);
trace_seq_puts(s, "\n ------------------------------------------\n\n");
}
static struct ftrace_graph_ret_entry *
get_return_for_leaf(struct trace_iterator *iter,
struct ftrace_graph_ent_entry *curr)
{
struct fgraph_data *data = iter->private;
struct ring_buffer_iter *ring_iter = NULL;
struct ring_buffer_event *event;
struct ftrace_graph_ret_entry *next;
/*
* If the previous output failed to write to the seq buffer,
* then we just reuse the data from before.
*/
if (data && data->failed) {
curr = &data->ent;
next = &data->ret;
} else {
ring_iter = trace_buffer_iter(iter, iter->cpu);
/* First peek to compare current entry and the next one */
if (ring_iter)
event = ring_buffer_iter_peek(ring_iter, NULL);
else {
/*
* We need to consume the current entry to see
* the next one.
*/
ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu,
NULL, NULL);
event = ring_buffer_peek(iter->trace_buffer->buffer, iter->cpu,
NULL, NULL);
}
if (!event)
return NULL;
next = ring_buffer_event_data(event);
if (data) {
/*
* Save current and next entries for later reference
* if the output fails.
*/
data->ent = *curr;
/*
* If the next event is not a return type, then
* we only care about what type it is. Otherwise we can
* safely copy the entire event.
*/
if (next->ent.type == TRACE_GRAPH_RET)
data->ret = *next;
else
data->ret.ent.type = next->ent.type;
}
}
if (next->ent.type != TRACE_GRAPH_RET)
return NULL;
if (curr->ent.pid != next->ent.pid ||
curr->graph_ent.func != next->ret.func)
return NULL;
/* this is a leaf, now advance the iterator */
if (ring_iter)
ring_buffer_read(ring_iter, NULL);
return next;
}
static void print_graph_abs_time(u64 t, struct trace_seq *s)
{
unsigned long usecs_rem;
usecs_rem = do_div(t, NSEC_PER_SEC);
usecs_rem /= 1000;
trace_seq_printf(s, "%5lu.%06lu | ",
(unsigned long)t, usecs_rem);
}
static void
print_graph_irq(struct trace_iterator *iter, unsigned long addr,
enum trace_type type, int cpu, pid_t pid, u32 flags)
{
struct trace_array *tr = iter->tr;
struct trace_seq *s = &iter->seq;
struct trace_entry *ent = iter->ent;
if (addr < (unsigned long)__irqentry_text_start ||
addr >= (unsigned long)__irqentry_text_end)
return;
if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
/* Absolute time */
if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
print_graph_abs_time(iter->ts, s);
/* Cpu */
if (flags & TRACE_GRAPH_PRINT_CPU)
print_graph_cpu(s, cpu);
/* Proc */
if (flags & TRACE_GRAPH_PRINT_PROC) {
print_graph_proc(s, pid);
trace_seq_puts(s, " | ");
}
/* Latency format */
if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
print_graph_lat_fmt(s, ent);
}
/* No overhead */
print_graph_duration(tr, 0, s, flags | FLAGS_FILL_START);
if (type == TRACE_GRAPH_ENT)
trace_seq_puts(s, "==========>");
else
trace_seq_puts(s, "<==========");
print_graph_duration(tr, 0, s, flags | FLAGS_FILL_END);
trace_seq_putc(s, '\n');
}
void
trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
{
unsigned long nsecs_rem = do_div(duration, 1000);
/* log10(ULONG_MAX) + '\0' */
char usecs_str[21];
char nsecs_str[5];
int len;
int i;
sprintf(usecs_str, "%lu", (unsigned long) duration);
/* Print msecs */
trace_seq_printf(s, "%s", usecs_str);
len = strlen(usecs_str);
/* 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);
snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
trace_seq_printf(s, ".%s", nsecs_str);
len += strlen(nsecs_str) + 1;
}
trace_seq_puts(s, " us ");
/* Print remaining spaces to fit the row's width */
for (i = len; i < 8; i++)
trace_seq_putc(s, ' ');
}
static void
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);
/* 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;