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Message-Id: <dd9d5f3d3781d1074bf554a473d49648dc79b359.1371751701.git.tom.zanussi@linux.intel.com>
Date: Thu, 20 Jun 2013 13:31:27 -0500
From: Tom Zanussi <tom.zanussi@...ux.intel.com>
To: rostedt@...dmis.org
Cc: masami.hiramatsu.pt@...achi.com, linux-kernel@...r.kernel.org,
Tom Zanussi <tom.zanussi@...ux.intel.com>
Subject: [PATCH 03/11] tracing: add soft disable for syscall events
Add support for SOFT_DISABLE to syscall events.
The original SOFT_DISABLE patches didn't add support for soft disable
of syscall events; this adds it and paves the way for future patches
allowing triggers to be added to syscall events, since triggers are
built on top of SOFT_DISABLE.
Because the trigger and SOFT_DISABLE bits are attached to the
ftrace_event_file associated with the event, pointers to the
ftrace_event_files associated with the event are added to the syscall
metadata entry for the event.
Signed-off-by: Tom Zanussi <tom.zanussi@...ux.intel.com>
---
include/linux/syscalls.h | 2 ++
include/trace/syscall.h | 5 +++++
kernel/trace/trace_syscalls.c | 28 ++++++++++++++++++++++++----
3 files changed, 31 insertions(+), 4 deletions(-)
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 4147d70..b4c2afa 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -158,6 +158,8 @@ extern struct trace_event_functions exit_syscall_print_funcs;
.args = nb ? args_##sname : NULL, \
.enter_event = &event_enter_##sname, \
.exit_event = &event_exit_##sname, \
+ .enter_file = NULL, /* Filled in at boot */ \
+ .exit_file = NULL, /* Filled in at boot */ \
.enter_fields = LIST_HEAD_INIT(__syscall_meta_##sname.enter_fields), \
}; \
static struct syscall_metadata __used \
diff --git a/include/trace/syscall.h b/include/trace/syscall.h
index fed853f..ba24d3a 100644
--- a/include/trace/syscall.h
+++ b/include/trace/syscall.h
@@ -19,6 +19,8 @@
* @enter_fields: list of fields for syscall_enter trace event
* @enter_event: associated syscall_enter trace event
* @exit_event: associated syscall_exit trace event
+ * @enter_file: associated syscall_enter ftrace event file
+ * @exit_file: associated syscall_exit ftrace event file
*/
struct syscall_metadata {
const char *name;
@@ -30,6 +32,9 @@ struct syscall_metadata {
struct ftrace_event_call *enter_event;
struct ftrace_event_call *exit_event;
+
+ struct ftrace_event_file *enter_file;
+ struct ftrace_event_file *exit_file;
};
#endif /* _TRACE_SYSCALL_H */
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 8f2ac73..1d81881 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -319,6 +319,10 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
if (!sys_data)
return;
+ if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT,
+ &sys_data->enter_file->flags))
+ return;
+
size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
buffer = tr->trace_buffer.buffer;
@@ -355,6 +359,10 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
if (!sys_data)
return;
+ if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT,
+ &sys_data->exit_file->flags))
+ return;
+
buffer = tr->trace_buffer.buffer;
event = trace_buffer_lock_reserve(buffer,
sys_data->exit_event->event.type, sizeof(*entry), 0, 0);
@@ -374,10 +382,12 @@ static int reg_event_syscall_enter(struct ftrace_event_file *file,
struct ftrace_event_call *call)
{
struct trace_array *tr = file->tr;
+ struct syscall_metadata *meta;
int ret = 0;
int num;
- num = ((struct syscall_metadata *)call->data)->syscall_nr;
+ meta = (struct syscall_metadata *)call->data;
+ num = meta->syscall_nr;
if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
return -ENOSYS;
mutex_lock(&syscall_trace_lock);
@@ -386,6 +396,7 @@ static int reg_event_syscall_enter(struct ftrace_event_file *file,
if (!ret) {
set_bit(num, tr->enabled_enter_syscalls);
tr->sys_refcount_enter++;
+ meta->enter_file = file;
}
mutex_unlock(&syscall_trace_lock);
return ret;
@@ -395,14 +406,17 @@ static void unreg_event_syscall_enter(struct ftrace_event_file *file,
struct ftrace_event_call *call)
{
struct trace_array *tr = file->tr;
+ struct syscall_metadata *meta;
int num;
- num = ((struct syscall_metadata *)call->data)->syscall_nr;
+ meta = (struct syscall_metadata *)call->data;
+ num = meta->syscall_nr;
if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
return;
mutex_lock(&syscall_trace_lock);
tr->sys_refcount_enter--;
clear_bit(num, tr->enabled_enter_syscalls);
+ meta->enter_file = NULL;
if (!tr->sys_refcount_enter)
unregister_trace_sys_enter(ftrace_syscall_enter, tr);
mutex_unlock(&syscall_trace_lock);
@@ -412,10 +426,12 @@ static int reg_event_syscall_exit(struct ftrace_event_file *file,
struct ftrace_event_call *call)
{
struct trace_array *tr = file->tr;
+ struct syscall_metadata *meta;
int ret = 0;
int num;
- num = ((struct syscall_metadata *)call->data)->syscall_nr;
+ meta = (struct syscall_metadata *)call->data;
+ num = meta->syscall_nr;
if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
return -ENOSYS;
mutex_lock(&syscall_trace_lock);
@@ -424,6 +440,7 @@ static int reg_event_syscall_exit(struct ftrace_event_file *file,
if (!ret) {
set_bit(num, tr->enabled_exit_syscalls);
tr->sys_refcount_exit++;
+ meta->exit_file = file;
}
mutex_unlock(&syscall_trace_lock);
return ret;
@@ -433,14 +450,17 @@ static void unreg_event_syscall_exit(struct ftrace_event_file *file,
struct ftrace_event_call *call)
{
struct trace_array *tr = file->tr;
+ struct syscall_metadata *meta;
int num;
- num = ((struct syscall_metadata *)call->data)->syscall_nr;
+ meta = (struct syscall_metadata *)call->data;
+ num = meta->syscall_nr;
if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
return;
mutex_lock(&syscall_trace_lock);
tr->sys_refcount_exit--;
clear_bit(num, tr->enabled_exit_syscalls);
+ meta->exit_file = NULL;
if (!tr->sys_refcount_exit)
unregister_trace_sys_exit(ftrace_syscall_exit, tr);
mutex_unlock(&syscall_trace_lock);
--
1.7.11.4
--
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