Hi Song,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on tip/perf/core]
[also build test ERROR on v4.20-rc5 next-20181206]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Song-Liu/perf-bpf-Introduce-PERF_RECORD_BPF_EVENT/20181207-083615
config: i386-randconfig-x070-201848 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All error/warnings (new ones prefixed by >>):

   kernel/events/core.c: In function 'perf_event_bpf_output':
>> kernel/events/core.c:7694:2: error: implicit declaration of function 'bpf_get_prog_name'; did you mean 'bpf_prog_free'? [-Werror=implicit-function-declaration]
     bpf_get_prog_name(bpf_event->prog, name);
     ^~~~~~~~~~~~~~~~~
     bpf_prog_free
   kernel/events/core.c: In function 'perf_event_bpf_event_subprog':
>> kernel/events/core.c:7737:12: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
       .addr = (u64)prog->bpf_func,
               ^
   cc1: some warnings being treated as errors

vim +7694 kernel/events/core.c

  7679	
  7680	static void perf_event_bpf_output(struct perf_event *event,
  7681					   void *data)
  7682	{
  7683		struct perf_bpf_event *bpf_event = data;
  7684		struct perf_output_handle handle;
  7685		struct perf_sample_data sample;
  7686		char name[KSYM_NAME_LEN];
  7687		int name_len;
  7688		int ret;
  7689	
  7690		if (!perf_event_bpf_match(event))
  7691			return;
  7692	
  7693		/* get prog name and round up to 64 bit aligned */
> 7694		bpf_get_prog_name(bpf_event->prog, name);
  7695		name_len = strlen(name) + 1;
  7696		while (!IS_ALIGNED(name_len, sizeof(u64)))
  7697			name[name_len++] = '\0';
  7698		bpf_event->event_id.len += name_len;
  7699	
  7700		perf_event_header__init_id(&bpf_event->event_id.header, &sample, event);
  7701		ret = perf_output_begin(&handle, event,
  7702					bpf_event->event_id.header.size);
  7703		if (ret)
  7704			return;
  7705	
  7706		perf_output_put(&handle, bpf_event->event_id);
  7707	
  7708		__output_copy(&handle, name, name_len);
  7709	
  7710		perf_event__output_id_sample(event, &handle, &sample);
  7711	
  7712		perf_output_end(&handle);
  7713	}
  7714	
  7715	static void perf_event_bpf(struct perf_bpf_event *bpf_event)
  7716	{
  7717		perf_iterate_sb(perf_event_bpf_output,
  7718			       bpf_event,
  7719			       NULL);
  7720	}
  7721	
  7722	static void perf_event_bpf_event_subprog(
  7723		enum perf_bpf_event_type type,
  7724		struct bpf_prog *prog, u32 id, u32 sub_id)
  7725	{
  7726		struct perf_bpf_event bpf_event = (struct perf_bpf_event){
  7727			.prog = prog,
  7728			.event_id = {
  7729				.header = {
  7730					.type = PERF_RECORD_BPF_EVENT,
  7731					.size = sizeof(bpf_event.event_id),
  7732				},
  7733				.type = type,
  7734				/* .flags = 0 */
  7735				.id = id,
  7736				.sub_id = sub_id,
> 7737				.addr = (u64)prog->bpf_func,
  7738				.len = prog->jited_len,
  7739			},
  7740		};
  7741	
  7742		memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
  7743		perf_event_bpf(&bpf_event);
  7744	}
  7745	

---
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