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.
The existing code grabs the trace_array from the ftrace_file passed to
the event registration functions and passes that to the probe
functions. Passing the file instead allows the probe functions to
access not only the trace_array attached to the file but the flags as
well.
Signed-off-by: Tom Zanussi <tom.zanu...@linux.intel.com>
---
kernel/trace/trace_syscalls.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 8f2ac73..1765088 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -301,7 +301,8 @@ static int __init syscall_exit_define_fields(struct
ftrace_event_call *call)
static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
{
- struct trace_array *tr = data;
+ struct ftrace_event_file *ftrace_file = data;
+ struct trace_array *tr = ftrace_file->tr;
struct syscall_trace_enter *entry;
struct syscall_metadata *sys_data;
struct ring_buffer_event *event;
@@ -319,6 +320,9 @@ 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, &ftrace_file->flags))
+ return;
+
size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
buffer = tr->trace_buffer.buffer;
@@ -338,7 +342,8 @@ static void ftrace_syscall_enter(void *data, struct pt_regs
*regs, long id)
static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
{
- struct trace_array *tr = data;
+ struct ftrace_event_file *ftrace_file = data;
+ struct trace_array *tr = ftrace_file->tr;
struct syscall_trace_exit *entry;
struct syscall_metadata *sys_data;
struct ring_buffer_event *event;
@@ -355,6 +360,9 @@ 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, &ftrace_file->flags))
+ return;
+
buffer = tr->trace_buffer.buffer;
event = trace_buffer_lock_reserve(buffer,
sys_data->exit_event->event.type, sizeof(*entry), 0, 0);
@@ -382,7 +390,7 @@ static int reg_event_syscall_enter(struct ftrace_event_file
*file,
return -ENOSYS;
mutex_lock(&syscall_trace_lock);
if (!tr->sys_refcount_enter)
- ret = register_trace_sys_enter(ftrace_syscall_enter, tr);
+ ret = register_trace_sys_enter(ftrace_syscall_enter, file);
if (!ret) {
set_bit(num, tr->enabled_enter_syscalls);
tr->sys_refcount_enter++;
@@ -404,7 +412,7 @@ static void unreg_event_syscall_enter(struct
ftrace_event_file *file,
tr->sys_refcount_enter--;
clear_bit(num, tr->enabled_enter_syscalls);
if (!tr->sys_refcount_enter)
- unregister_trace_sys_enter(ftrace_syscall_enter, tr);
+ unregister_trace_sys_enter(ftrace_syscall_enter, file);
mutex_unlock(&syscall_trace_lock);
}
@@ -420,7 +428,7 @@ static int reg_event_syscall_exit(struct ftrace_event_file
*file,
return -ENOSYS;
mutex_lock(&syscall_trace_lock);
if (!tr->sys_refcount_exit)
- ret = register_trace_sys_exit(ftrace_syscall_exit, tr);
+ ret = register_trace_sys_exit(ftrace_syscall_exit, file);
if (!ret) {
set_bit(num, tr->enabled_exit_syscalls);
tr->sys_refcount_exit++;
@@ -442,7 +450,7 @@ static void unreg_event_syscall_exit(struct
ftrace_event_file *file,
tr->sys_refcount_exit--;
clear_bit(num, tr->enabled_exit_syscalls);
if (!tr->sys_refcount_exit)
- unregister_trace_sys_exit(ftrace_syscall_exit, tr);
+ unregister_trace_sys_exit(ftrace_syscall_exit, file);
mutex_unlock(&syscall_trace_lock);
}
--
1.7.11.4
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