kernel-ark/kernel/trace/trace_output.c
Steven Rostedt f633cef020 ftrace: change trace.c to use registered events
Impact: rework trace.c to use new event register API

Almost every ftrace event has to implement its output display in
trace.c through a different function. Some events did not handle
all the formats (trace, latency-trace, raw, hex, binary), and
this method does not scale well.

This patch converts the format functions to use the event API to
find the event and and print its format. Currently, we have
a print function for trace, latency_trace, raw, hex and binary.
A trace_nop_print is available if the event wants to avoid output
on a particular format.

Perhaps other tracers could use this in the future (like mmiotrace and
function_graph).

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-29 12:46:12 +01:00

833 lines
17 KiB
C

/*
* trace_output.c
*
* Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
*
*/
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/ftrace.h>
#include "trace_output.h"
/* must be a power of 2 */
#define EVENT_HASHSIZE 128
static DEFINE_MUTEX(trace_event_mutex);
static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
static int next_event_type = __TRACE_LAST_TYPE + 1;
/**
* trace_seq_printf - sequence printing of trace information
* @s: trace sequence descriptor
* @fmt: printf format string
*
* The tracer may use either sequence operations or its own
* copy to user routines. To simplify formating of a trace
* trace_seq_printf is used to store strings into a special
* buffer (@s). Then the output may be either used by
* the sequencer or pulled into another buffer.
*/
int
trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
{
int len = (PAGE_SIZE - 1) - s->len;
va_list ap;
int ret;
if (!len)
return 0;
va_start(ap, fmt);
ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
va_end(ap);
/* If we can't write it all, don't bother writing anything */
if (ret >= len)
return 0;
s->len += ret;
return len;
}
/**
* trace_seq_puts - trace sequence printing of simple string
* @s: trace sequence descriptor
* @str: simple string to record
*
* The tracer may use either the sequence operations or its own
* copy to user routines. This function records a simple string
* into a special buffer (@s) for later retrieval by a sequencer
* or other mechanism.
*/
int trace_seq_puts(struct trace_seq *s, const char *str)
{
int len = strlen(str);
if (len > ((PAGE_SIZE - 1) - s->len))
return 0;
memcpy(s->buffer + s->len, str, len);
s->len += len;
return len;
}
int trace_seq_putc(struct trace_seq *s, unsigned char c)
{
if (s->len >= (PAGE_SIZE - 1))
return 0;
s->buffer[s->len++] = c;
return 1;
}
int trace_seq_putmem(struct trace_seq *s, void *mem, size_t len)
{
if (len > ((PAGE_SIZE - 1) - s->len))
return 0;
memcpy(s->buffer + s->len, mem, len);
s->len += len;
return len;
}
int trace_seq_putmem_hex(struct trace_seq *s, void *mem, size_t len)
{
unsigned char hex[HEX_CHARS];
unsigned char *data = mem;
int i, j;
#ifdef __BIG_ENDIAN
for (i = 0, j = 0; i < len; i++) {
#else
for (i = len-1, j = 0; i >= 0; i--) {
#endif
hex[j++] = hex_asc_hi(data[i]);
hex[j++] = hex_asc_lo(data[i]);
}
hex[j++] = ' ';
return trace_seq_putmem(s, hex, j);
}
int trace_seq_path(struct trace_seq *s, struct path *path)
{
unsigned char *p;
if (s->len >= (PAGE_SIZE - 1))
return 0;
p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len);
if (!IS_ERR(p)) {
p = mangle_path(s->buffer + s->len, p, "\n");
if (p) {
s->len = p - s->buffer;
return 1;
}
} else {
s->buffer[s->len++] = '?';
return 1;
}
return 0;
}
#ifdef CONFIG_KRETPROBES
static inline const char *kretprobed(const char *name)
{
static const char tramp_name[] = "kretprobe_trampoline";
int size = sizeof(tramp_name);
if (strncmp(tramp_name, name, size) == 0)
return "[unknown/kretprobe'd]";
return name;
}
#else
static inline const char *kretprobed(const char *name)
{
return name;
}
#endif /* CONFIG_KRETPROBES */
static int
seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
{
#ifdef CONFIG_KALLSYMS
char str[KSYM_SYMBOL_LEN];
const char *name;
kallsyms_lookup(address, NULL, NULL, NULL, str);
name = kretprobed(str);
return trace_seq_printf(s, fmt, name);
#endif
return 1;
}
static int
seq_print_sym_offset(struct trace_seq *s, const char *fmt,
unsigned long address)
{
#ifdef CONFIG_KALLSYMS
char str[KSYM_SYMBOL_LEN];
const char *name;
sprint_symbol(str, address);
name = kretprobed(str);
return trace_seq_printf(s, fmt, name);
#endif
return 1;
}
#ifndef CONFIG_64BIT
# define IP_FMT "%08lx"
#else
# define IP_FMT "%016lx"
#endif
int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
unsigned long ip, unsigned long sym_flags)
{
struct file *file = NULL;
unsigned long vmstart = 0;
int ret = 1;
if (mm) {
const struct vm_area_struct *vma;
down_read(&mm->mmap_sem);
vma = find_vma(mm, ip);
if (vma) {
file = vma->vm_file;
vmstart = vma->vm_start;
}
if (file) {
ret = trace_seq_path(s, &file->f_path);
if (ret)
ret = trace_seq_printf(s, "[+0x%lx]",
ip - vmstart);
}
up_read(&mm->mmap_sem);
}
if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file))
ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
return ret;
}
int
seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s,
unsigned long sym_flags)
{
struct mm_struct *mm = NULL;
int ret = 1;
unsigned int i;
if (trace_flags & TRACE_ITER_SYM_USEROBJ) {
struct task_struct *task;
/*
* we do the lookup on the thread group leader,
* since individual threads might have already quit!
*/
rcu_read_lock();
task = find_task_by_vpid(entry->ent.tgid);
if (task)
mm = get_task_mm(task);
rcu_read_unlock();
}
for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
unsigned long ip = entry->caller[i];
if (ip == ULONG_MAX || !ret)
break;
if (i && ret)
ret = trace_seq_puts(s, " <- ");
if (!ip) {
if (ret)
ret = trace_seq_puts(s, "??");
continue;
}
if (!ret)
break;
if (ret)
ret = seq_print_user_ip(s, mm, ip, sym_flags);
}
if (mm)
mmput(mm);
return ret;
}
int
seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
{
int ret;
if (!ip)
return trace_seq_printf(s, "0");
if (sym_flags & TRACE_ITER_SYM_OFFSET)
ret = seq_print_sym_offset(s, "%s", ip);
else
ret = seq_print_sym_short(s, "%s", ip);
if (!ret)
return 0;
if (sym_flags & TRACE_ITER_SYM_ADDR)
ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
return ret;
}
static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
static int task_state_char(unsigned long state)
{
int bit = state ? __ffs(state) + 1 : 0;
return bit < sizeof(state_to_char) - 1 ? state_to_char[bit] : '?';
}
/**
* ftrace_find_event - find a registered event
* @type: the type of event to look for
*
* Returns an event of type @type otherwise NULL
*/
struct trace_event *ftrace_find_event(int type)
{
struct trace_event *event;
struct hlist_node *n;
unsigned key;
key = type & (EVENT_HASHSIZE - 1);
hlist_for_each_entry_rcu(event, n, &event_hash[key], node) {
if (event->type == type)
return event;
}
return NULL;
}
/**
* register_ftrace_event - register output for an event type
* @event: the event type to register
*
* Event types are stored in a hash and this hash is used to
* find a way to print an event. If the @event->type is set
* then it will use that type, otherwise it will assign a
* type to use.
*
* If you assign your own type, please make sure it is added
* to the trace_type enum in trace.h, to avoid collisions
* with the dynamic types.
*
* Returns the event type number or zero on error.
*/
int register_ftrace_event(struct trace_event *event)
{
unsigned key;
int ret = 0;
mutex_lock(&trace_event_mutex);
if (!event->type)
event->type = next_event_type++;
else if (event->type > __TRACE_LAST_TYPE) {
printk(KERN_WARNING "Need to add type to trace.h\n");
WARN_ON(1);
}
if (ftrace_find_event(event->type))
goto out;
key = event->type & (EVENT_HASHSIZE - 1);
hlist_add_head_rcu(&event->node, &event_hash[key]);
ret = event->type;
out:
mutex_unlock(&trace_event_mutex);
return ret;
}
/**
* unregister_ftrace_event - remove a no longer used event
* @event: the event to remove
*/
int unregister_ftrace_event(struct trace_event *event)
{
mutex_lock(&trace_event_mutex);
hlist_del(&event->node);
mutex_unlock(&trace_event_mutex);
return 0;
}
/*
* Standard events
*/
int
trace_nop_print(struct trace_seq *s, struct trace_entry *entry, int flags)
{
return 0;
}
/* TRACE_FN */
static int
trace_fn_latency(struct trace_seq *s, struct trace_entry *entry, int flags)
{
struct ftrace_entry *field;
trace_assign_type(field, entry);
if (!seq_print_ip_sym(s, field->ip, flags))
goto partial;
if (!trace_seq_puts(s, " ("))
goto partial;
if (!seq_print_ip_sym(s, field->parent_ip, flags))
goto partial;
if (!trace_seq_puts(s, ")\n"))
goto partial;
return 0;
partial:
return TRACE_TYPE_PARTIAL_LINE;
}
static int
trace_fn_trace(struct trace_seq *s, struct trace_entry *entry, int flags)
{
struct ftrace_entry *field;
trace_assign_type(field, entry);
if (!seq_print_ip_sym(s, field->ip, flags))
goto partial;
if ((flags & TRACE_ITER_PRINT_PARENT) && field->parent_ip) {
if (!trace_seq_printf(s, " <-"))
goto partial;
if (!seq_print_ip_sym(s,
field->parent_ip,
flags))
goto partial;
}
if (!trace_seq_printf(s, "\n"))
goto partial;
return 0;
partial:
return TRACE_TYPE_PARTIAL_LINE;
}
static int
trace_fn_raw(struct trace_seq *s, struct trace_entry *entry, int flags)
{
struct ftrace_entry *field;
trace_assign_type(field, entry);
if (trace_seq_printf(s, "%x %x\n",
field->ip,
field->parent_ip))
return TRACE_TYPE_PARTIAL_LINE;
return 0;
}
static int
trace_fn_hex(struct trace_seq *s, struct trace_entry *entry, int flags)
{
struct ftrace_entry *field;
trace_assign_type(field, entry);
SEQ_PUT_HEX_FIELD_RET(s, field->ip);
SEQ_PUT_HEX_FIELD_RET(s, field->parent_ip);
return 0;
}
static int
trace_fn_bin(struct trace_seq *s, struct trace_entry *entry, int flags)
{
struct ftrace_entry *field;
trace_assign_type(field, entry);
SEQ_PUT_FIELD_RET(s, field->ip);
SEQ_PUT_FIELD_RET(s, field->parent_ip);
return 0;
}
static struct trace_event trace_fn_event = {
.type = TRACE_FN,
.trace = trace_fn_trace,
.latency_trace = trace_fn_latency,
.raw = trace_fn_raw,
.hex = trace_fn_hex,
.binary = trace_fn_bin,
};
/* TRACE_CTX an TRACE_WAKE */
static int
trace_ctxwake_print(struct trace_seq *s, struct trace_entry *entry, int flags,
char *delim)
{
struct ctx_switch_entry *field;
char *comm;
int S, T;
trace_assign_type(field, entry);
T = task_state_char(field->next_state);
S = task_state_char(field->prev_state);
comm = trace_find_cmdline(field->next_pid);
if (trace_seq_printf(s, " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
field->prev_pid,
field->prev_prio,
S, delim,
field->next_cpu,
field->next_pid,
field->next_prio,
T, comm))
return TRACE_TYPE_PARTIAL_LINE;
return 0;
}
static int
trace_ctx_print(struct trace_seq *s, struct trace_entry *entry, int flags)
{
return trace_ctxwake_print(s, entry, flags, "==>");
}
static int
trace_wake_print(struct trace_seq *s, struct trace_entry *entry, int flags)
{
return trace_ctxwake_print(s, entry, flags, " +");
}
static int
trace_ctxwake_raw(struct trace_seq *s, struct trace_entry *entry, int flags,
char S)
{
struct ctx_switch_entry *field;
int T;
trace_assign_type(field, entry);
if (!S)
task_state_char(field->prev_state);
T = task_state_char(field->next_state);
if (trace_seq_printf(s, "%d %d %c %d %d %d %c\n",
field->prev_pid,
field->prev_prio,
S,
field->next_cpu,
field->next_pid,
field->next_prio,
T))
return TRACE_TYPE_PARTIAL_LINE;
return 0;
}
static int
trace_ctx_raw(struct trace_seq *s, struct trace_entry *entry, int flags)
{
return trace_ctxwake_raw(s, entry, flags, 0);
}
static int
trace_wake_raw(struct trace_seq *s, struct trace_entry *entry, int flags)
{
return trace_ctxwake_raw(s, entry, flags, '+');
}
static int
trace_ctxwake_hex(struct trace_seq *s, struct trace_entry *entry, int flags,
char S)
{
struct ctx_switch_entry *field;
int T;
trace_assign_type(field, entry);
if (!S)
task_state_char(field->prev_state);
T = task_state_char(field->next_state);
SEQ_PUT_HEX_FIELD_RET(s, field->prev_pid);
SEQ_PUT_HEX_FIELD_RET(s, field->prev_prio);
SEQ_PUT_HEX_FIELD_RET(s, S);
SEQ_PUT_HEX_FIELD_RET(s, field->next_cpu);
SEQ_PUT_HEX_FIELD_RET(s, field->next_pid);
SEQ_PUT_HEX_FIELD_RET(s, field->next_prio);
SEQ_PUT_HEX_FIELD_RET(s, T);
return 0;
}
static int
trace_ctx_hex(struct trace_seq *s, struct trace_entry *entry, int flags)
{
return trace_ctxwake_hex(s, entry, flags, 0);
}
static int
trace_wake_hex(struct trace_seq *s, struct trace_entry *entry, int flags)
{
return trace_ctxwake_hex(s, entry, flags, '+');
}
static int
trace_ctxwake_bin(struct trace_seq *s, struct trace_entry *entry, int flags)
{
struct ctx_switch_entry *field;
trace_assign_type(field, entry);
SEQ_PUT_FIELD_RET(s, field->prev_pid);
SEQ_PUT_FIELD_RET(s, field->prev_prio);
SEQ_PUT_FIELD_RET(s, field->prev_state);
SEQ_PUT_FIELD_RET(s, field->next_pid);
SEQ_PUT_FIELD_RET(s, field->next_prio);
SEQ_PUT_FIELD_RET(s, field->next_state);
return 0;
}
static struct trace_event trace_ctx_event = {
.type = TRACE_CTX,
.trace = trace_ctx_print,
.latency_trace = trace_ctx_print,
.raw = trace_ctx_raw,
.hex = trace_ctx_hex,
.binary = trace_ctxwake_bin,
};
static struct trace_event trace_wake_event = {
.type = TRACE_WAKE,
.trace = trace_wake_print,
.latency_trace = trace_wake_print,
.raw = trace_wake_raw,
.hex = trace_wake_hex,
.binary = trace_ctxwake_bin,
};
/* TRACE_SPECIAL */
static int
trace_special_print(struct trace_seq *s, struct trace_entry *entry, int flags)
{
struct special_entry *field;
trace_assign_type(field, entry);
if (trace_seq_printf(s, "# %ld %ld %ld\n",
field->arg1,
field->arg2,
field->arg3))
return TRACE_TYPE_PARTIAL_LINE;
return 0;
}
static int
trace_special_hex(struct trace_seq *s, struct trace_entry *entry, int flags)
{
struct special_entry *field;
trace_assign_type(field, entry);
SEQ_PUT_HEX_FIELD_RET(s, field->arg1);
SEQ_PUT_HEX_FIELD_RET(s, field->arg2);
SEQ_PUT_HEX_FIELD_RET(s, field->arg3);
return 0;
}
static int
trace_special_bin(struct trace_seq *s, struct trace_entry *entry, int flags)
{
struct special_entry *field;
trace_assign_type(field, entry);
SEQ_PUT_FIELD_RET(s, field->arg1);
SEQ_PUT_FIELD_RET(s, field->arg2);
SEQ_PUT_FIELD_RET(s, field->arg3);
return 0;
}
static struct trace_event trace_special_event = {
.type = TRACE_SPECIAL,
.trace = trace_special_print,
.latency_trace = trace_special_print,
.raw = trace_special_print,
.hex = trace_special_hex,
.binary = trace_special_bin,
};
/* TRACE_STACK */
static int
trace_stack_print(struct trace_seq *s, struct trace_entry *entry, int flags)
{
struct stack_entry *field;
int i;
trace_assign_type(field, entry);
for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
if (i) {
if (trace_seq_puts(s, " <= "))
goto partial;
if (seq_print_ip_sym(s, field->caller[i], flags))
goto partial;
}
if (trace_seq_puts(s, "\n"))
goto partial;
}
return 0;
partial:
return TRACE_TYPE_PARTIAL_LINE;
}
static struct trace_event trace_stack_event = {
.type = TRACE_STACK,
.trace = trace_stack_print,
.latency_trace = trace_stack_print,
.raw = trace_special_print,
.hex = trace_special_hex,
.binary = trace_special_bin,
};
/* TRACE_USER_STACK */
static int
trace_user_stack_print(struct trace_seq *s, struct trace_entry *entry,
int flags)
{
struct userstack_entry *field;
trace_assign_type(field, entry);
if (seq_print_userip_objs(field, s, flags))
goto partial;
if (trace_seq_putc(s, '\n'))
goto partial;
return 0;
partial:
return TRACE_TYPE_PARTIAL_LINE;
}
static struct trace_event trace_user_stack_event = {
.type = TRACE_USER_STACK,
.trace = trace_user_stack_print,
.latency_trace = trace_user_stack_print,
.raw = trace_special_print,
.hex = trace_special_hex,
.binary = trace_special_bin,
};
/* TRACE_PRINT */
static int
trace_print_print(struct trace_seq *s, struct trace_entry *entry, int flags)
{
struct print_entry *field;
trace_assign_type(field, entry);
if (seq_print_ip_sym(s, field->ip, flags))
goto partial;
if (trace_seq_printf(s, ": %s", field->buf))
goto partial;
return 0;
partial:
return TRACE_TYPE_PARTIAL_LINE;
}
static int
trace_print_raw(struct trace_seq *s, struct trace_entry *entry, int flags)
{
struct print_entry *field;
trace_assign_type(field, entry);
if (seq_print_ip_sym(s, field->ip, flags))
goto partial;
if (trace_seq_printf(s, "# %lx %s", field->ip, field->buf))
goto partial;
return 0;
partial:
return TRACE_TYPE_PARTIAL_LINE;
}
static struct trace_event trace_print_event = {
.type = TRACE_PRINT,
.trace = trace_print_print,
.latency_trace = trace_print_print,
.raw = trace_print_raw,
.hex = trace_nop_print,
.binary = trace_nop_print,
};
static struct trace_event *events[] __initdata = {
&trace_fn_event,
&trace_ctx_event,
&trace_wake_event,
&trace_special_event,
&trace_stack_event,
&trace_user_stack_event,
&trace_print_event,
NULL
};
__init static int init_events(void)
{
struct trace_event *event;
int i, ret;
for (i = 0; events[i]; i++) {
event = events[i];
ret = register_ftrace_event(event);
if (!ret) {
printk(KERN_WARNING "event %d failed to register\n",
event->type);
WARN_ON_ONCE(1);
}
}
return 0;
}
device_initcall(init_events);