Commit d509db04 authored by Wang Nan's avatar Wang Nan Committed by Arnaldo Carvalho de Melo
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perf tools: Compile scriptlets to BPF objects when passing '.c' to --event 



This patch provides infrastructure for passing source files to --event
directly using:

 # perf record --event bpf-file.c command

This patch does following works:

 1) Allow passing '.c' file to '--event'. parse_events_load_bpf() is
    expanded to allow caller tell it whether the passed file is source
    file or object.

 2) llvm__compile_bpf() is called to compile the '.c' file, the result
    is saved into memory. Use bpf_object__open_buffer() to load the
    in-memory object.

Introduces a bpf-script-example.c so we can manually test it:

 # perf record --clang-opt "-DLINUX_VERSION_CODE=0x40200" --event ./bpf-script-example.c sleep 1

Note that '--clang-opt' must put before '--event'.

Futher patches will merge it into a testcase so can be tested automatically.

Signed-off-by: default avatarWang Nan <wangnan0@huawei.com>
Acked-by: default avatarAlexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1444826502-49291-10-git-send-email-wangnan0@huawei.com


Signed-off-by: default avatarHe Kuang <hekuang@huawei.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 71dc2326

tools/perf/tests/bpf-script-example.c

0 → 100644
+44 −0
Original line number Original line Diff line number Diff line 
#ifndef LINUX_VERSION_CODE

# error Need LINUX_VERSION_CODE

# error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig'

#endif

#define BPF_ANY 0

#define BPF_MAP_TYPE_ARRAY 2

#define BPF_FUNC_map_lookup_elem 1

#define BPF_FUNC_map_update_elem 2



static void *(*bpf_map_lookup_elem)(void *map, void *key) =

	(void *) BPF_FUNC_map_lookup_elem;

static void *(*bpf_map_update_elem)(void *map, void *key, void *value, int flags) =

	(void *) BPF_FUNC_map_update_elem;



struct bpf_map_def {

	unsigned int type;

	unsigned int key_size;

	unsigned int value_size;

	unsigned int max_entries;

};



#define SEC(NAME) __attribute__((section(NAME), used))

struct bpf_map_def SEC("maps") flip_table = {

	.type = BPF_MAP_TYPE_ARRAY,

	.key_size = sizeof(int),

	.value_size = sizeof(int),

	.max_entries = 1,

};



SEC("func=sys_epoll_pwait")

int bpf_func__sys_epoll_pwait(void *ctx)

{

	int ind =0;

	int *flag = bpf_map_lookup_elem(&flip_table, &ind);

	int new_flag;

	if (!flag)

		return 0;

	/* flip flag and store back */

	new_flag = !*flag;

	bpf_map_update_elem(&flip_table, &ind, &new_flag, BPF_ANY);

	return new_flag;

}

char _license[] SEC("license") = "GPL";

int _version SEC("version") = LINUX_VERSION_CODE;

tools/perf/util/bpf-loader.c

+15 −2
Original line number Original line Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include "bpf-loader.h"

#include "bpf-loader.h"

#include "probe-event.h"

#include "probe-event.h"

#include "probe-finder.h" // for MAX_PROBES

#include "probe-finder.h" // for MAX_PROBES

#include "llvm-utils.h"





#define DEFINE_PRINT_FN(name, level) \

#define DEFINE_PRINT_FN(name, level) \

static int libbpf_##name(const char *fmt, ...)	\

static int libbpf_##name(const char *fmt, ...)	\
@@ -33,7 +34,7 @@ struct bpf_prog_priv { 
	struct perf_probe_event pev;

	struct perf_probe_event pev;

};

};





struct bpf_object *bpf__prepare_load(const char *filename)

struct bpf_object *bpf__prepare_load(const char *filename, bool source)

{

{

	struct bpf_object *obj;

	struct bpf_object *obj;

	static bool libbpf_initialized;

	static bool libbpf_initialized;
@@ -45,7 +46,19 @@ struct bpf_object *bpf__prepare_load(const char *filename) 
		libbpf_initialized = true;

		libbpf_initialized = true;

	}

	}





	if (source) {

		int err;

		void *obj_buf;

		size_t obj_buf_sz;



		err = llvm__compile_bpf(filename, &obj_buf, &obj_buf_sz);

		if (err)

			return ERR_PTR(err);

		obj = bpf_object__open_buffer(obj_buf, obj_buf_sz, filename);

		free(obj_buf);

	} else

		obj = bpf_object__open(filename);

		obj = bpf_object__open(filename);



	if (!obj) {

	if (!obj) {

		pr_debug("bpf: failed to load %s\n", filename);

		pr_debug("bpf: failed to load %s\n", filename);

		return ERR_PTR(-EINVAL);

		return ERR_PTR(-EINVAL);

tools/perf/util/bpf-loader.h

+3 −2
Original line number Original line Diff line number Diff line
@@ -18,7 +18,7 @@ typedef int (*bpf_prog_iter_callback_t)(struct probe_trace_event *tev, 
					int fd, void *arg);

					int fd, void *arg);





#ifdef HAVE_LIBBPF_SUPPORT

#ifdef HAVE_LIBBPF_SUPPORT

struct bpf_object *bpf__prepare_load(const char *filename);

struct bpf_object *bpf__prepare_load(const char *filename, bool source);





void bpf__clear(void);

void bpf__clear(void);
@@ -34,7 +34,8 @@ int bpf__foreach_tev(struct bpf_object *obj, 
		     bpf_prog_iter_callback_t func, void *arg);

		     bpf_prog_iter_callback_t func, void *arg);

#else

#else

static inline struct bpf_object *

static inline struct bpf_object *

bpf__prepare_load(const char *filename __maybe_unused)

bpf__prepare_load(const char *filename __maybe_unused,

		  bool source __maybe_unused)

{

{

	pr_debug("ERROR: eBPF object loading is disabled during compiling.\n");

	pr_debug("ERROR: eBPF object loading is disabled during compiling.\n");

	return ERR_PTR(-ENOTSUP);

	return ERR_PTR(-ENOTSUP);

tools/perf/util/parse-events.c

+3 −2
Original line number Original line Diff line number Diff line
@@ -626,11 +626,12 @@ errout: 




int parse_events_load_bpf(struct parse_events_evlist *data,

int parse_events_load_bpf(struct parse_events_evlist *data,

			  struct list_head *list,

			  struct list_head *list,

			  char *bpf_file_name)

			  char *bpf_file_name,

			  bool source)

{

{

	struct bpf_object *obj;

	struct bpf_object *obj;





	obj = bpf__prepare_load(bpf_file_name);

	obj = bpf__prepare_load(bpf_file_name, source);

	if (IS_ERR(obj) || !obj) {

	if (IS_ERR(obj) || !obj) {

		char errbuf[BUFSIZ];

		char errbuf[BUFSIZ];

		int err;

		int err;

tools/perf/util/parse-events.h

+2 −1
Original line number Original line Diff line number Diff line
@@ -125,7 +125,8 @@ int parse_events_add_tracepoint(struct list_head *list, int *idx, 
				struct list_head *head_config);

				struct list_head *head_config);

int parse_events_load_bpf(struct parse_events_evlist *data,

int parse_events_load_bpf(struct parse_events_evlist *data,

			  struct list_head *list,

			  struct list_head *list,

			  char *bpf_file_name);

			  char *bpf_file_name,

			  bool source);

/* Provide this function for perf test */

/* Provide this function for perf test */

struct bpf_object;

struct bpf_object;

int parse_events_load_bpf_obj(struct parse_events_evlist *data,

int parse_events_load_bpf_obj(struct parse_events_evlist *data,

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