Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[safe/jmp/linux-2.6] / kernel / trace / trace_kprobe.c

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 6178abf..505c922 100644 (file)
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -635,12 +635,12 @@ static int create_trace_probe(int argc, char **argv)
                        event = strchr(group, '/') + 1;
                        event[-1] = '\0';
                        if (strlen(group) == 0) {
-                               pr_info("Group name is not specifiled\n");
+                               pr_info("Group name is not specified\n");
                                return -EINVAL;
                        }
                }
                if (strlen(event) == 0) {
-                       pr_info("Event name is not specifiled\n");
+                       pr_info("Event name is not specified\n");
                        return -EINVAL;
                }
        }
@@ -673,7 +673,7 @@ static int create_trace_probe(int argc, char **argv)
                        return -EINVAL;
                }
                /* an address specified */
-               ret = strict_strtoul(&argv[0][2], 0, (unsigned long *)&addr);
+               ret = strict_strtoul(&argv[1][0], 0, (unsigned long *)&addr);
                if (ret) {
                        pr_info("Failed to parse address.\n");
                        return ret;
@@ -1155,80 +1155,60 @@ static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
        return 0;
 }
 
-static int __probe_event_show_format(struct trace_seq *s,
-                                    struct trace_probe *tp, const char *fmt,
-                                    const char *arg)
+static int __set_print_fmt(struct trace_probe *tp, char *buf, int len)
 {
        int i;
+       int pos = 0;
 
-       /* Show format */
-       if (!trace_seq_printf(s, "\nprint fmt: \"%s", fmt))
-               return 0;
+       const char *fmt, *arg;
 
-       for (i = 0; i < tp->nr_args; i++)
-               if (!trace_seq_printf(s, " %s=%%lx", tp->args[i].name))
-                       return 0;
+       if (!probe_is_return(tp)) {
+               fmt = "(%lx)";
+               arg = "REC->" FIELD_STRING_IP;
+       } else {
+               fmt = "(%lx <- %lx)";
+               arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
+       }
 
-       if (!trace_seq_printf(s, "\", %s", arg))
-               return 0;
+       /* When len=0, we just calculate the needed length */
+#define LEN_OR_ZERO (len ? len - pos : 0)
 
-       for (i = 0; i < tp->nr_args; i++)
-               if (!trace_seq_printf(s, ", REC->%s", tp->args[i].name))
-                       return 0;
+       pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
 
-       return trace_seq_puts(s, "\n");
-}
+       for (i = 0; i < tp->nr_args; i++) {
+               pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%%lx",
+                               tp->args[i].name);
+       }
 
-#undef SHOW_FIELD
-#define SHOW_FIELD(type, item, name)                                   \
-       do {                                                            \
-               ret = trace_seq_printf(s, "\tfield:" #type " %s;\t"     \
-                               "offset:%u;\tsize:%u;\tsigned:%d;\n", name,\
-                               (unsigned int)offsetof(typeof(field), item),\
-                               (unsigned int)sizeof(type),             \
-                               is_signed_type(type));                  \
-               if (!ret)                                               \
-                       return 0;                                       \
-       } while (0)
+       pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
 
-static int kprobe_event_show_format(struct ftrace_event_call *call,
-                                   struct trace_seq *s)
-{
-       struct kprobe_trace_entry field __attribute__((unused));
-       int ret, i;
-       struct trace_probe *tp = (struct trace_probe *)call->data;
-
-       SHOW_FIELD(unsigned long, ip, FIELD_STRING_IP);
-       SHOW_FIELD(int, nargs, FIELD_STRING_NARGS);
+       for (i = 0; i < tp->nr_args; i++) {
+               pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
+                               tp->args[i].name);
+       }
 
-       /* Show fields */
-       for (i = 0; i < tp->nr_args; i++)
-               SHOW_FIELD(unsigned long, args[i], tp->args[i].name);
-       trace_seq_puts(s, "\n");
+#undef LEN_OR_ZERO
 
-       return __probe_event_show_format(s, tp, "(%lx)",
-                                        "REC->" FIELD_STRING_IP);
+       /* return the length of print_fmt */
+       return pos;
 }
 
-static int kretprobe_event_show_format(struct ftrace_event_call *call,
-                                      struct trace_seq *s)
+static int set_print_fmt(struct trace_probe *tp)
 {
-       struct kretprobe_trace_entry field __attribute__((unused));
-       int ret, i;
-       struct trace_probe *tp = (struct trace_probe *)call->data;
+       int len;
+       char *print_fmt;
 
-       SHOW_FIELD(unsigned long, func, FIELD_STRING_FUNC);
-       SHOW_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP);
-       SHOW_FIELD(int, nargs, FIELD_STRING_NARGS);
+       /* First: called with 0 length to calculate the needed length */
+       len = __set_print_fmt(tp, NULL, 0);
+       print_fmt = kmalloc(len + 1, GFP_KERNEL);
+       if (!print_fmt)
+               return -ENOMEM;
 
-       /* Show fields */
-       for (i = 0; i < tp->nr_args; i++)
-               SHOW_FIELD(unsigned long, args[i], tp->args[i].name);
-       trace_seq_puts(s, "\n");
+       /* Second: actually write the @print_fmt */
+       __set_print_fmt(tp, print_fmt, len + 1);
+       tp->call.print_fmt = print_fmt;
 
-       return __probe_event_show_format(s, tp, "(%lx <- %lx)",
-                                        "REC->" FIELD_STRING_FUNC
-                                        ", REC->" FIELD_STRING_RETIP);
+       return 0;
 }
 
 #ifdef CONFIG_PERF_EVENTS
@@ -1359,18 +1339,20 @@ static int register_probe_event(struct trace_probe *tp)
        if (probe_is_return(tp)) {
                tp->event.trace = print_kretprobe_event;
                call->raw_init = probe_event_raw_init;
-               call->show_format = kretprobe_event_show_format;
                call->define_fields = kretprobe_event_define_fields;
        } else {
                tp->event.trace = print_kprobe_event;
                call->raw_init = probe_event_raw_init;
-               call->show_format = kprobe_event_show_format;
                call->define_fields = kprobe_event_define_fields;
        }
+       if (set_print_fmt(tp) < 0)
+               return -ENOMEM;
        call->event = &tp->event;
        call->id = register_ftrace_event(&tp->event);
-       if (!call->id)
+       if (!call->id) {
+               kfree(call->print_fmt);
                return -ENODEV;
+       }
        call->enabled = 0;
        call->regfunc = probe_event_enable;
        call->unregfunc = probe_event_disable;
@@ -1383,6 +1365,7 @@ static int register_probe_event(struct trace_probe *tp)
        ret = trace_add_event_call(call);
        if (ret) {
                pr_info("Failed to register kprobe event: %s\n", call->name);
+               kfree(call->print_fmt);
                unregister_ftrace_event(&tp->event);
        }
        return ret;
@@ -1392,6 +1375,7 @@ static void unregister_probe_event(struct trace_probe *tp)
 {
        /* tp->event is unregistered in trace_remove_event_call() */
        trace_remove_event_call(&tp->call);
+       kfree(tp->call.print_fmt);
 }
 
 /* Make a debugfs interface for controling probe points */