tracing/perf: Move the PERF_MAX_TRACE_SIZE check into perf_trace_buf_prepare()

[linux-imx.git] / kernel / trace / trace_syscalls.c

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 8f2ac73c7a5fd9a6c8412b7b96e1cc0473651d62..8fd03657bc7d1f684279c46681519e16a1812f87 100644 (file)
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -175,7 +175,7 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
        entry = syscall_nr_to_meta(syscall);
 
        if (!entry) {
-               trace_seq_printf(s, "\n");
+               trace_seq_putc(s, '\n');
                return TRACE_TYPE_HANDLED;
        }
 
@@ -306,6 +306,8 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
        struct syscall_metadata *sys_data;
        struct ring_buffer_event *event;
        struct ring_buffer *buffer;
+       unsigned long irq_flags;
+       int pc;
        int syscall_nr;
        int size;
 
@@ -321,9 +323,12 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
 
        size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
 
+       local_save_flags(irq_flags);
+       pc = preempt_count();
+
        buffer = tr->trace_buffer.buffer;
        event = trace_buffer_lock_reserve(buffer,
-                       sys_data->enter_event->event.type, size, 0, 0);
+                       sys_data->enter_event->event.type, size, irq_flags, pc);
        if (!event)
                return;
 
@@ -333,7 +338,8 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
 
        if (!filter_current_check_discard(buffer, sys_data->enter_event,
                                          entry, event))
-               trace_current_buffer_unlock_commit(buffer, event, 0, 0);
+               trace_current_buffer_unlock_commit(buffer, event,
+                                                  irq_flags, pc);
 }
 
 static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
@@ -343,6 +349,8 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
        struct syscall_metadata *sys_data;
        struct ring_buffer_event *event;
        struct ring_buffer *buffer;
+       unsigned long irq_flags;
+       int pc;
        int syscall_nr;
 
        syscall_nr = trace_get_syscall_nr(current, regs);
@@ -355,9 +363,13 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
        if (!sys_data)
                return;
 
+       local_save_flags(irq_flags);
+       pc = preempt_count();
+
        buffer = tr->trace_buffer.buffer;
        event = trace_buffer_lock_reserve(buffer,
-                       sys_data->exit_event->event.type, sizeof(*entry), 0, 0);
+                       sys_data->exit_event->event.type, sizeof(*entry),
+                       irq_flags, pc);
        if (!event)
                return;
 
@@ -367,7 +379,8 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
 
        if (!filter_current_check_discard(buffer, sys_data->exit_event,
                                          entry, event))
-               trace_current_buffer_unlock_commit(buffer, event, 0, 0);
+               trace_current_buffer_unlock_commit(buffer, event,
+                                                  irq_flags, pc);
 }
 
 static int reg_event_syscall_enter(struct ftrace_event_file *file,
@@ -553,15 +566,15 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
        if (!sys_data)
                return;
 
+       head = this_cpu_ptr(sys_data->enter_event->perf_events);
+       if (hlist_empty(head))
+               return;
+
        /* get the size after alignment with the u32 buffer size field */
        size = sizeof(unsigned long) * sys_data->nb_args + sizeof(*rec);
        size = ALIGN(size + sizeof(u32), sizeof(u64));
        size -= sizeof(u32);
 
-       if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
-                     "perf buffer not large enough"))
-               return;
-
        rec = (struct syscall_trace_enter *)perf_trace_buf_prepare(size,
                                sys_data->enter_event->event.type, regs, &rctx);
        if (!rec)
@@ -570,8 +583,6 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
        rec->nr = syscall_nr;
        syscall_get_arguments(current, regs, 0, sys_data->nb_args,
                               (unsigned long *)&rec->args);
-
-       head = this_cpu_ptr(sys_data->enter_event->perf_events);
        perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head, NULL);
 }
 
@@ -629,18 +640,14 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
        if (!sys_data)
                return;
 
+       head = this_cpu_ptr(sys_data->exit_event->perf_events);
+       if (hlist_empty(head))
+               return;
+
        /* We can probably do that at build time */
        size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
        size -= sizeof(u32);
 
-       /*
-        * Impossible, but be paranoid with the future
-        * How to put this check outside runtime?
-        */
-       if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
-               "exit event has grown above perf buffer size"))
-               return;
-
        rec = (struct syscall_trace_exit *)perf_trace_buf_prepare(size,
                                sys_data->exit_event->event.type, regs, &rctx);
        if (!rec)
@@ -648,8 +655,6 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
 
        rec->nr = syscall_nr;
        rec->ret = syscall_get_return_value(current, regs);
-
-       head = this_cpu_ptr(sys_data->exit_event->perf_events);
        perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head, NULL);
 }