Commit 917f6b7b authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Alexei Starovoitov
Browse files

libbpf: Add BPF_EMBED_OBJ macro for embedding BPF .o files 



Add a convenience macro BPF_EMBED_OBJ, which allows to embed other files
(typically used to embed BPF .o files) into a hosting userspace programs. To
C program it is exposed as struct bpf_embed_data, containing a pointer to
raw data and its size in bytes.

Signed-off-by: default avatarAndrii Nakryiko <andriin@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191214014341.3442258-5-andriin@fb.com
parent 612d05be

tools/lib/bpf/libbpf.h

+35 −0
Original line number Diff line number Diff line
@@ -615,6 +615,41 @@ bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear); 
 */

LIBBPF_API int libbpf_num_possible_cpus(void);



struct bpf_embed_data {

	void *data;

	size_t size;

};



#define BPF_EMBED_OBJ_DECLARE(NAME)					\

extern struct bpf_embed_data NAME##_embed;				\

extern char NAME##_data[];						\

extern char NAME##_data_end[];



#define __BPF_EMBED_OBJ(NAME, PATH, SZ, ASM_TYPE)			\

asm (									\

"	.pushsection \".rodata\", \"a\", @progbits		\n"	\

"	.global "#NAME"_data					\n"	\

#NAME"_data:							\n"	\

"	.incbin \"" PATH "\"					\n"	\

"	.global "#NAME"_data_end				\n"	\

#NAME"_data_end:						\n"	\

"	.global "#NAME"_embed					\n"	\

"	.type "#NAME"_embed, @object				\n"	\

"	.size "#NAME"_size, "#SZ"				\n"	\

"	.align 8,						\n"	\

#NAME"_embed:							\n"	\

"	"ASM_TYPE" "#NAME"_data					\n"	\

"	"ASM_TYPE" "#NAME"_data_end - "#NAME"_data 		\n"	\

"	.popsection						\n"	\

);									\

BPF_EMBED_OBJ_DECLARE(NAME)



#if __SIZEOF_POINTER__ == 4

#define BPF_EMBED_OBJ(NAME, PATH) __BPF_EMBED_OBJ(NAME, PATH, 8, ".long")

#else

#define BPF_EMBED_OBJ(NAME, PATH) __BPF_EMBED_OBJ(NAME, PATH, 16, ".quad")

#endif



#ifdef __cplusplus

} /* extern "C" */

#endif

tools/testing/selftests/bpf/prog_tests/attach_probe.c

+3 −20
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

#include <test_progs.h>



#define EMBED_FILE(NAME, PATH)						    \

asm (									    \

"      .pushsection \".rodata\", \"a\", @progbits              \n"	    \

"      .global "#NAME"_data                                    \n"	    \

#NAME"_data:                                                   \n"	    \

"      .incbin \"" PATH "\"                                    \n"	    \

#NAME"_data_end:                                               \n"	    \

"      .global "#NAME"_size                                    \n"	    \

"      .type "#NAME"_size, @object                             \n"	    \

"      .size "#NAME"_size, 4                                   \n"	    \

"      .align 4,                                               \n"	    \

#NAME"_size:                                                   \n"	    \

"      .int "#NAME"_data_end - "#NAME"_data                    \n"	    \

"      .popsection                                             \n"	    \

);									    \

extern char NAME##_data[];						    \

extern int NAME##_size;



ssize_t get_base_addr() {

	size_t start;

	char buf[256];
@@ -39,7 +21,7 @@ ssize_t get_base_addr() { 
	return -EINVAL;

}



EMBED_FILE(probe, "test_attach_probe.o");

BPF_EMBED_OBJ(probe, "test_attach_probe.o");



void test_attach_probe(void)

{
@@ -73,7 +55,8 @@ void test_attach_probe(void) 
	uprobe_offset = (size_t)&get_base_addr - base_addr;



	/* open object */

	obj = bpf_object__open_mem(probe_data, probe_size, &open_opts);

	obj = bpf_object__open_mem(probe_embed.data, probe_embed.size,

				   &open_opts);

	if (CHECK(IS_ERR(obj), "obj_open_mem", "err %ld\n", PTR_ERR(obj)))

		return;

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