4 * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
8 #include <linux/module.h>
9 #include <linux/mutex.h>
10 #include <linux/ftrace.h>
12 #include "trace_output.h"
14 /* must be a power of 2 */
15 #define EVENT_HASHSIZE 128
17 static DEFINE_MUTEX(trace_event_mutex);
18 static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
20 static int next_event_type = __TRACE_LAST_TYPE + 1;
23 * trace_seq_printf - sequence printing of trace information
24 * @s: trace sequence descriptor
25 * @fmt: printf format string
27 * The tracer may use either sequence operations or its own
28 * copy to user routines. To simplify formating of a trace
29 * trace_seq_printf is used to store strings into a special
30 * buffer (@s). Then the output may be either used by
31 * the sequencer or pulled into another buffer.
34 trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
36 int len = (PAGE_SIZE - 1) - s->len;
44 ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
47 /* If we can't write it all, don't bother writing anything */
57 * trace_seq_puts - trace sequence printing of simple string
58 * @s: trace sequence descriptor
59 * @str: simple string to record
61 * The tracer may use either the sequence operations or its own
62 * copy to user routines. This function records a simple string
63 * into a special buffer (@s) for later retrieval by a sequencer
66 int trace_seq_puts(struct trace_seq *s, const char *str)
68 int len = strlen(str);
70 if (len > ((PAGE_SIZE - 1) - s->len))
73 memcpy(s->buffer + s->len, str, len);
79 int trace_seq_putc(struct trace_seq *s, unsigned char c)
81 if (s->len >= (PAGE_SIZE - 1))
84 s->buffer[s->len++] = c;
89 int trace_seq_putmem(struct trace_seq *s, void *mem, size_t len)
91 if (len > ((PAGE_SIZE - 1) - s->len))
94 memcpy(s->buffer + s->len, mem, len);
100 int trace_seq_putmem_hex(struct trace_seq *s, void *mem, size_t len)
102 unsigned char hex[HEX_CHARS];
103 unsigned char *data = mem;
107 for (i = 0, j = 0; i < len; i++) {
109 for (i = len-1, j = 0; i >= 0; i--) {
111 hex[j++] = hex_asc_hi(data[i]);
112 hex[j++] = hex_asc_lo(data[i]);
116 return trace_seq_putmem(s, hex, j);
119 int trace_seq_path(struct trace_seq *s, struct path *path)
123 if (s->len >= (PAGE_SIZE - 1))
125 p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len);
127 p = mangle_path(s->buffer + s->len, p, "\n");
129 s->len = p - s->buffer;
133 s->buffer[s->len++] = '?';
140 #ifdef CONFIG_KRETPROBES
141 static inline const char *kretprobed(const char *name)
143 static const char tramp_name[] = "kretprobe_trampoline";
144 int size = sizeof(tramp_name);
146 if (strncmp(tramp_name, name, size) == 0)
147 return "[unknown/kretprobe'd]";
151 static inline const char *kretprobed(const char *name)
155 #endif /* CONFIG_KRETPROBES */
158 seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
160 #ifdef CONFIG_KALLSYMS
161 char str[KSYM_SYMBOL_LEN];
164 kallsyms_lookup(address, NULL, NULL, NULL, str);
166 name = kretprobed(str);
168 return trace_seq_printf(s, fmt, name);
174 seq_print_sym_offset(struct trace_seq *s, const char *fmt,
175 unsigned long address)
177 #ifdef CONFIG_KALLSYMS
178 char str[KSYM_SYMBOL_LEN];
181 sprint_symbol(str, address);
182 name = kretprobed(str);
184 return trace_seq_printf(s, fmt, name);
190 # define IP_FMT "%08lx"
192 # define IP_FMT "%016lx"
195 int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
196 unsigned long ip, unsigned long sym_flags)
198 struct file *file = NULL;
199 unsigned long vmstart = 0;
203 const struct vm_area_struct *vma;
205 down_read(&mm->mmap_sem);
206 vma = find_vma(mm, ip);
209 vmstart = vma->vm_start;
212 ret = trace_seq_path(s, &file->f_path);
214 ret = trace_seq_printf(s, "[+0x%lx]",
217 up_read(&mm->mmap_sem);
219 if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file))
220 ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
225 seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s,
226 unsigned long sym_flags)
228 struct mm_struct *mm = NULL;
232 if (trace_flags & TRACE_ITER_SYM_USEROBJ) {
233 struct task_struct *task;
235 * we do the lookup on the thread group leader,
236 * since individual threads might have already quit!
239 task = find_task_by_vpid(entry->ent.tgid);
241 mm = get_task_mm(task);
245 for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
246 unsigned long ip = entry->caller[i];
248 if (ip == ULONG_MAX || !ret)
251 ret = trace_seq_puts(s, " <- ");
254 ret = trace_seq_puts(s, "??");
260 ret = seq_print_user_ip(s, mm, ip, sym_flags);
269 seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
274 return trace_seq_printf(s, "0");
276 if (sym_flags & TRACE_ITER_SYM_OFFSET)
277 ret = seq_print_sym_offset(s, "%s", ip);
279 ret = seq_print_sym_short(s, "%s", ip);
284 if (sym_flags & TRACE_ITER_SYM_ADDR)
285 ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
290 * ftrace_find_event - find a registered event
291 * @type: the type of event to look for
293 * Returns an event of type @type otherwise NULL
295 struct trace_event *ftrace_find_event(int type)
297 struct trace_event *event;
298 struct hlist_node *n;
301 key = type & (EVENT_HASHSIZE - 1);
303 hlist_for_each_entry_rcu(event, n, &event_hash[key], node) {
304 if (event->type == type)
312 * register_ftrace_event - register output for an event type
313 * @event: the event type to register
315 * Event types are stored in a hash and this hash is used to
316 * find a way to print an event. If the @event->type is set
317 * then it will use that type, otherwise it will assign a
320 * If you assign your own type, please make sure it is added
321 * to the trace_type enum in trace.h, to avoid collisions
322 * with the dynamic types.
324 * Returns the event type number or zero on error.
326 int register_ftrace_event(struct trace_event *event)
331 mutex_lock(&trace_event_mutex);
334 event->type = next_event_type++;
335 else if (event->type > __TRACE_LAST_TYPE) {
336 printk(KERN_WARNING "Need to add type to trace.h\n");
340 if (ftrace_find_event(event->type))
343 key = event->type & (EVENT_HASHSIZE - 1);
345 hlist_add_head_rcu(&event->node, &event_hash[key]);
349 mutex_unlock(&trace_event_mutex);
355 * unregister_ftrace_event - remove a no longer used event
356 * @event: the event to remove
358 int unregister_ftrace_event(struct trace_event *event)
360 mutex_lock(&trace_event_mutex);
361 hlist_del(&event->node);
362 mutex_unlock(&trace_event_mutex);