bpf: add support for sys_enter_* and sys_exit_* tracepoints

[linux-2.6-microblaze.git] / kernel / trace / trace_syscalls.c

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 5e10395..7a1a920 100644 (file)
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -559,11 +559,29 @@ static DECLARE_BITMAP(enabled_perf_exit_syscalls, NR_syscalls);
 static int sys_perf_refcount_enter;
 static int sys_perf_refcount_exit;
 
+static int perf_call_bpf_enter(struct bpf_prog *prog, struct pt_regs *regs,
+                             struct syscall_metadata *sys_data,
+                             struct syscall_trace_enter *rec) {
+       struct syscall_tp_t {
+               unsigned long long regs;
+               unsigned long syscall_nr;
+               unsigned long args[sys_data->nb_args];
+       } param;
+       int i;
+
+       *(struct pt_regs **)&param = regs;
+       param.syscall_nr = rec->nr;
+       for (i = 0; i < sys_data->nb_args; i++)
+               param.args[i] = rec->args[i];
+       return trace_call_bpf(prog, &param);
+}
+
 static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
 {
        struct syscall_metadata *sys_data;
        struct syscall_trace_enter *rec;
        struct hlist_head *head;
+       struct bpf_prog *prog;
        int syscall_nr;
        int rctx;
        int size;
@@ -578,8 +596,9 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
        if (!sys_data)
                return;
 
+       prog = READ_ONCE(sys_data->enter_event->prog);
        head = this_cpu_ptr(sys_data->enter_event->perf_events);
-       if (hlist_empty(head))
+       if (!prog && hlist_empty(head))
                return;
 
        /* get the size after alignment with the u32 buffer size field */
@@ -594,6 +613,13 @@ 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);
+
+       if ((prog && !perf_call_bpf_enter(prog, regs, sys_data, rec)) ||
+           hlist_empty(head)) {
+               perf_swevent_put_recursion_context(rctx);
+               return;
+       }
+
        perf_trace_buf_submit(rec, size, rctx,
                              sys_data->enter_event->event.type, 1, regs,
                              head, NULL);
@@ -633,11 +659,26 @@ static void perf_sysenter_disable(struct trace_event_call *call)
        mutex_unlock(&syscall_trace_lock);
 }
 
+static int perf_call_bpf_exit(struct bpf_prog *prog, struct pt_regs *regs,
+                             struct syscall_trace_exit *rec) {
+       struct syscall_tp_t {
+               unsigned long long regs;
+               unsigned long syscall_nr;
+               unsigned long ret;
+       } param;
+
+       *(struct pt_regs **)&param = regs;
+       param.syscall_nr = rec->nr;
+       param.ret = rec->ret;
+       return trace_call_bpf(prog, &param);
+}
+
 static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
 {
        struct syscall_metadata *sys_data;
        struct syscall_trace_exit *rec;
        struct hlist_head *head;
+       struct bpf_prog *prog;
        int syscall_nr;
        int rctx;
        int size;
@@ -652,8 +693,9 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
        if (!sys_data)
                return;
 
+       prog = READ_ONCE(sys_data->exit_event->prog);
        head = this_cpu_ptr(sys_data->exit_event->perf_events);
-       if (hlist_empty(head))
+       if (!prog && hlist_empty(head))
                return;
 
        /* We can probably do that at build time */
@@ -666,6 +708,13 @@ 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);
+
+       if ((prog && !perf_call_bpf_exit(prog, regs, rec)) ||
+           hlist_empty(head)) {
+               perf_swevent_put_recursion_context(rctx);
+               return;
+       }
+
        perf_trace_buf_submit(rec, size, rctx, sys_data->exit_event->event.type,
                              1, regs, head, NULL);
 }