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authorLai Jiangshan <laijs@cn.fujitsu.com>2009-12-15 15:39:45 +0800
committerSteven Rostedt <rostedt@goodmis.org>2010-01-06 11:58:32 -0500
commit50307a45f8515f6244e3b08e6b19824b9fbfe293 (patch)
tree3561b9824617845910c09a4f7ef5d29ea6159ddf /kernel
parent509e760cd91c831983097ae174cb6c0b8c6c8e6b (diff)
downloadvexpress-lsk-50307a45f8515f6244e3b08e6b19824b9fbfe293.tar.gz
tracing/syscalls: Init print_fmt for syscall events
This is part of a patch set that removes the show_format method in the ftrace event macros. Add the print_fmt initialization to the syscall events. The print_fmt is still not used, but will be in the follow up patches. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <4B273D41.609@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace_syscalls.c68
1 files changed, 67 insertions, 1 deletions
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 75289f372dd..1352b0a36fa 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -191,6 +191,67 @@ int syscall_enter_format(struct ftrace_event_call *call, struct trace_seq *s)
return trace_seq_putc(s, '\n');
}
+static
+int __set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len)
+{
+ int i;
+ int pos = 0;
+
+ /* When len=0, we just calculate the needed length */
+#define LEN_OR_ZERO (len ? len - pos : 0)
+
+ pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
+ for (i = 0; i < entry->nb_args; i++) {
+ pos += snprintf(buf + pos, LEN_OR_ZERO, "%s: 0x%%0%zulx%s",
+ entry->args[i], sizeof(unsigned long),
+ i == entry->nb_args - 1 ? "" : ", ");
+ }
+ pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
+
+ for (i = 0; i < entry->nb_args; i++) {
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ ", ((unsigned long)(REC->%s))", entry->args[i]);
+ }
+
+#undef LEN_OR_ZERO
+
+ /* return the length of print_fmt */
+ return pos;
+}
+
+static int set_syscall_print_fmt(struct ftrace_event_call *call)
+{
+ char *print_fmt;
+ int len;
+ struct syscall_metadata *entry = call->data;
+
+ if (entry->enter_event != call) {
+ call->print_fmt = "\"0x%lx\", REC->ret";
+ return 0;
+ }
+
+ /* First: called with 0 length to calculate the needed length */
+ len = __set_enter_print_fmt(entry, NULL, 0);
+
+ print_fmt = kmalloc(len + 1, GFP_KERNEL);
+ if (!print_fmt)
+ return -ENOMEM;
+
+ /* Second: actually write the @print_fmt */
+ __set_enter_print_fmt(entry, print_fmt, len + 1);
+ call->print_fmt = print_fmt;
+
+ return 0;
+}
+
+static void free_syscall_print_fmt(struct ftrace_event_call *call)
+{
+ struct syscall_metadata *entry = call->data;
+
+ if (entry->enter_event == call)
+ kfree(call->print_fmt);
+}
+
int syscall_exit_format(struct ftrace_event_call *call, struct trace_seq *s)
{
int ret;
@@ -386,9 +447,14 @@ int init_syscall_trace(struct ftrace_event_call *call)
{
int id;
+ if (set_syscall_print_fmt(call) < 0)
+ return -ENOMEM;
+
id = register_ftrace_event(call->event);
- if (!id)
+ if (!id) {
+ free_syscall_print_fmt(call);
return -ENODEV;
+ }
call->id = id;
INIT_LIST_HEAD(&call->fields);
return 0;