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 <[email protected]> --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
