linux/kernel/trace/trace_functions_graph.c
Alexander Potapenko be7635e728 arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections
KASAN needs to know whether the allocation happens in an IRQ handler.
This lets us strip everything below the IRQ entry point to reduce the
number of unique stack traces needed to be stored.

Move the definition of __irq_entry to <linux/interrupt.h> so that the
users don't need to pull in <linux/ftrace.h>.  Also introduce the
__softirq_entry macro which is similar to __irq_entry, but puts the
corresponding functions to the .softirqentry.text section.

Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-25 16:37:42 -07:00

1485 lines
36 KiB
C

/*
*
* 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"
static bool kill_ftrace_graph;
/**
* ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called
*
* ftrace_graph_stop() is called when a severe error is detected in
* the function graph tracing. This function is called by the critical
* paths of function graph to keep those paths from doing any more harm.
*/
bool ftrace_graph_is_dead(void)
{
return kill_ftrace_graph;
}
/**
* ftrace_graph_stop - set to permanently disable function graph tracincg
*
* In case of an error int function graph tracing, this is called
* to try to keep function graph tracing from causing any more harm.
* Usually this is pretty severe and this is called to try to at least
* get a warning out to the user.
*/
void ftrace_graph_stop(void)
{
kill_ftrace_graph = true;
}
/* 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
static unsigned int 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);
/* Add a function return address to the trace stack on thread info.*/
int
ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
unsigned long frame_pointer)
{
unsigned long long calltime;
int index;
if (unlikely(ftrace_graph_is_dead()))
return -EBUSY;
if (!current->ret_stack)
return -EBUSY;
/*
* We must make sure the ret_stack is tested before we read
* anything else.
*/
smp_rmb();
/* The return trace stack is full */
if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
atomic_inc(&current->trace_overrun);
return -EBUSY;
}
/*
* The curr_ret_stack is an index to ftrace return stack of
* current task. Its value should be in [0, FTRACE_RETFUNC_
* DEPTH) when the function graph tracer is used. To support
* filtering out specific functions, it makes the index
* negative by subtracting huge value (FTRACE_NOTRACE_DEPTH)
* so when it sees a negative index the ftrace will ignore
* the record. And the index gets recovered when returning
* from the filtered function by adding the FTRACE_NOTRACE_
* DEPTH and then it'll continue to record functions normally.
*
* The curr_ret_stack is initialized to -1 and get increased
* in this function. So it can be less than -1 only if it was
* filtered out via ftrace_graph_notrace_addr() which can be
* set from set_graph_notrace file in tracefs by user.
*/
if (current->curr_ret_stack < -1)
return -EBUSY;
calltime = trace_clock_local();
index = ++current->curr_ret_stack;
if (ftrace_graph_notrace_addr(func))
current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH;
barrier();
current->ret_stack[index].ret = ret;
current->ret_stack[index].func = func;
current->ret_stack[index].calltime = calltime;
current->ret_stack[index].subtime = 0;
current->ret_stack[index].fp = frame_pointer;
*depth = current->curr_ret_stack;
return 0;
}
/* Retrieve a function return address to the trace stack on thread info.*/
static void
ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
unsigned long frame_pointer)
{
int index;
index = current->curr_ret_stack;
/*
* A negative index here means that it's just returned from a
* notrace'd function. Recover index to get an original
* return address. See ftrace_push_return_trace().
*
* TODO: Need to check whether the stack gets corrupted.
*/
if (index < 0)
index += FTRACE_NOTRACE_DEPTH;
if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
ftrace_graph_stop();
WARN_ON(1);
/* Might as well panic, otherwise we have no where to go */
*ret = (unsigned long)panic;
return;
}
#if defined(CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST) && !defined(CC_USING_FENTRY)
/*
* The arch may choose to record the frame pointer used
* and check it here to make sure that it is what we expect it
* to be. If gcc does not set the place holder of the return
* address in the frame pointer, and does a copy instead, then
* the function graph trace will fail. This test detects this
* case.
*
* Currently, x86_32 with optimize for size (-Os) makes the latest
* gcc do the above.
*
* Note, -mfentry does not use frame pointers, and this test
* is not needed if CC_USING_FENTRY is set.
*/
if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
ftrace_graph_stop();
WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
" from func %ps return to %lx\n",
current->ret_stack[index].fp,
frame_pointer,
(void *)current->ret_stack[index].func,
current->ret_stack[index].ret);
*ret = (unsigned long)panic;
return;
}
#endif
*ret = current->ret_stack[index].ret;
trace->func = current->ret_stack[index].func;
trace->calltime = current->ret_stack[index].calltime;
trace->overrun = atomic_read(&current->trace_overrun);
trace->depth = index;
}
/*
* Send the trace to the ring-buffer.
* @return the original return address.
*/
unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
{
struct ftrace_graph_ret trace;
unsigned long ret;
ftrace_pop_return_trace(&trace, &ret, frame_pointer);
trace.rettime = trace_clock_local();
barrier();
current->curr_ret_stack--;
/*
* The curr_ret_stack can be less than -1 only if it was
* filtered out and it's about to return from the function.
* Recover the index and continue to trace normal functions.
*/
if (current->curr_ret_stack < -1) {
current->curr_ret_stack += FTRACE_NOTRACE_DEPTH;
return ret;
}
/*
* The trace should run after decrementing the ret counter
* in case an interrupt were to come in. We don't want to
* lose the interrupt if max_depth is set.
*/
ftrace_graph_return(&trace);
if (unlikely(!ret)) {
ftrace_graph_stop();
WARN_ON(1);
/* Might as well panic. What else to do? */
ret = (unsigned long)panic;
}
return ret;
}
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))
__buffer_unlock_commit(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 (!ftrace_trace_task(current))
return 0;
/* trace it when it is-nested-in or is a function enabled. */
if ((!(trace->depth || ftrace_graph_addr(trace->func)) ||
ftrace_graph_ignore_irqs()) || (trace->depth < 0) ||
(max_depth && trace->depth >= max_depth))
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;
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 int trace_graph_thresh_entry(struct ftrace_graph_ent *trace)
{
if (tracing_thresh)
return 1;
else
return trace_graph_entry(trace);
}
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))
__buffer_unlock_commit(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;
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)
{
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_thresh_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 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;
int cpu = iter->cpu;
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)
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);
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)
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) {
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_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_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_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_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;
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", 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)
{
struct dentry *d_tracer;
d_tracer = tracing_init_dentry();
if (IS_ERR(d_tracer))
return 0;
trace_create_file("max_graph_depth", 0644, d_tracer,
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, "%d", 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);