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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: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191214014341.3442258-5-andriin@fb.com
alistair/sensors
Andrii Nakryiko 2019-12-13 17:43:28 -08:00 committed by Alexei Starovoitov
parent 612d05be25
commit 917f6b7b07
2 changed files with 38 additions and 20 deletions
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35
tools/lib/bpf/libbpf.h
View File

@ -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

23
tools/testing/selftests/bpf/prog_tests/attach_probe.c
View File

@ -1,24 +1,6 @@
// 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;