diff options
Diffstat (limited to 'tools/lib')
-rw-r--r-- | tools/lib/bpf/libbpf.c | 260 |
1 files changed, 140 insertions, 120 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 74f7d9252d13..a7320d272b34 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -462,6 +462,20 @@ struct module_btf { int fd_array_idx; }; +enum sec_type { + SEC_UNUSED = 0, + SEC_RELO, + SEC_BSS, + SEC_DATA, + SEC_RODATA, +}; + +struct elf_sec_desc { + enum sec_type sec_type; + Elf64_Shdr *shdr; + Elf_Data *data; +}; + struct elf_state { int fd; const void *obj_buf; @@ -469,25 +483,16 @@ struct elf_state { Elf *elf; Elf64_Ehdr *ehdr; Elf_Data *symbols; - Elf_Data *data; - Elf_Data *rodata; - Elf_Data *bss; Elf_Data *st_ops_data; size_t shstrndx; /* section index for section name strings */ size_t strtabidx; - struct { - Elf64_Shdr *shdr; - Elf_Data *data; - } *reloc_sects; - int nr_reloc_sects; + struct elf_sec_desc *secs; + int sec_cnt; int maps_shndx; int btf_maps_shndx; __u32 btf_maps_sec_btf_id; int text_shndx; int symbols_shndx; - int data_shndx; - int rodata_shndx; - int bss_shndx; int st_ops_shndx; }; @@ -506,10 +511,10 @@ struct bpf_object { struct extern_desc *externs; int nr_extern; int kconfig_map_idx; - int rodata_map_idx; bool loaded; bool has_subcalls; + bool has_rodata; struct bpf_gen *gen_loader; @@ -1168,12 +1173,8 @@ static struct bpf_object *bpf_object__new(const char *path, obj->efile.obj_buf_sz = obj_buf_sz; obj->efile.maps_shndx = -1; obj->efile.btf_maps_shndx = -1; - obj->efile.data_shndx = -1; - obj->efile.rodata_shndx = -1; - obj->efile.bss_shndx = -1; obj->efile.st_ops_shndx = -1; obj->kconfig_map_idx = -1; - obj->rodata_map_idx = -1; obj->kern_version = get_kernel_version(); obj->loaded = false; @@ -1193,13 +1194,10 @@ static void bpf_object__elf_finish(struct bpf_object *obj) obj->efile.elf = NULL; } obj->efile.symbols = NULL; - obj->efile.data = NULL; - obj->efile.rodata = NULL; - obj->efile.bss = NULL; obj->efile.st_ops_data = NULL; - zfree(&obj->efile.reloc_sects); - obj->efile.nr_reloc_sects = 0; + zfree(&obj->efile.secs); + obj->efile.sec_cnt = 0; zclose(obj->efile.fd); obj->efile.obj_buf = NULL; obj->efile.obj_buf_sz = 0; @@ -1340,30 +1338,18 @@ static bool bpf_map_type__is_map_in_map(enum bpf_map_type type) static int find_elf_sec_sz(const struct bpf_object *obj, const char *name, __u32 *size) { int ret = -ENOENT; + Elf_Data *data; + Elf_Scn *scn; *size = 0; - if (!name) { + if (!name) return -EINVAL; - } else if (!strcmp(name, DATA_SEC)) { - if (obj->efile.data) - *size = obj->efile.data->d_size; - } else if (!strcmp(name, BSS_SEC)) { - if (obj->efile.bss) - *size = obj->efile.bss->d_size; - } else if (!strcmp(name, RODATA_SEC)) { - if (obj->efile.rodata) - *size = obj->efile.rodata->d_size; - } else if (!strcmp(name, STRUCT_OPS_SEC)) { - if (obj->efile.st_ops_data) - *size = obj->efile.st_ops_data->d_size; - } else { - Elf_Scn *scn = elf_sec_by_name(obj, name); - Elf_Data *data = elf_sec_data(obj, scn); - if (data) { - ret = 0; /* found it */ - *size = data->d_size; - } + scn = elf_sec_by_name(obj, name); + data = elf_sec_data(obj, scn); + if (data) { + ret = 0; /* found it */ + *size = data->d_size; } return *size ? 0 : ret; @@ -1516,34 +1502,39 @@ bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type, static int bpf_object__init_global_data_maps(struct bpf_object *obj) { - int err; + struct elf_sec_desc *sec_desc; + int err = 0, sec_idx; /* * Populate obj->maps with libbpf internal maps. */ - if (obj->efile.data_shndx >= 0) { - err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA, - obj->efile.data_shndx, - obj->efile.data->d_buf, - obj->efile.data->d_size); - if (err) - return err; - } - if (obj->efile.rodata_shndx >= 0) { - err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA, - obj->efile.rodata_shndx, - obj->efile.rodata->d_buf, - obj->efile.rodata->d_size); - if (err) - return err; - - obj->rodata_map_idx = obj->nr_maps - 1; - } - if (obj->efile.bss_shndx >= 0) { - err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS, - obj->efile.bss_shndx, - NULL, - obj->efile.bss->d_size); + for (sec_idx = 1; sec_idx < obj->efile.sec_cnt; sec_idx++) { + sec_desc = &obj->efile.secs[sec_idx]; + + switch (sec_desc->sec_type) { + case SEC_DATA: + err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA, + sec_idx, + sec_desc->data->d_buf, + sec_desc->data->d_size); + break; + case SEC_RODATA: + obj->has_rodata = true; + err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA, + sec_idx, + sec_desc->data->d_buf, + sec_desc->data->d_size); + break; + case SEC_BSS: + err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS, + sec_idx, + NULL, + sec_desc->data->d_size); + break; + default: + /* skip */ + break; + } if (err) return err; } @@ -3123,6 +3114,7 @@ static int cmp_progs(const void *_a, const void *_b) static int bpf_object__elf_collect(struct bpf_object *obj) { + struct elf_sec_desc *sec_desc; Elf *elf = obj->efile.elf; Elf_Data *btf_ext_data = NULL; Elf_Data *btf_data = NULL; @@ -3132,6 +3124,15 @@ static int bpf_object__elf_collect(struct bpf_object *obj) Elf_Scn *scn; Elf64_Shdr *sh; + /* ELF section indices are 1-based, so allocate +1 element to keep + * indexing simple. Also include 0th invalid section into sec_cnt for + * simpler and more traditional iteration logic. + */ + obj->efile.sec_cnt = 1 + obj->efile.ehdr->e_shnum; + obj->efile.secs = calloc(obj->efile.sec_cnt, sizeof(*obj->efile.secs)); + if (!obj->efile.secs) + return -ENOMEM; + /* a bunch of ELF parsing functionality depends on processing symbols, * so do the first pass and find the symbol table */ @@ -3151,8 +3152,10 @@ static int bpf_object__elf_collect(struct bpf_object *obj) if (!data) return -LIBBPF_ERRNO__FORMAT; + idx = elf_ndxscn(scn); + obj->efile.symbols = data; - obj->efile.symbols_shndx = elf_ndxscn(scn); + obj->efile.symbols_shndx = idx; obj->efile.strtabidx = sh->sh_link; } } @@ -3165,7 +3168,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj) scn = NULL; while ((scn = elf_nextscn(elf, scn)) != NULL) { - idx++; + idx = elf_ndxscn(scn); + sec_desc = &obj->efile.secs[idx]; sh = elf_sec_hdr(obj, scn); if (!sh) @@ -3213,11 +3217,13 @@ static int bpf_object__elf_collect(struct bpf_object *obj) if (err) return err; } else if (strcmp(name, DATA_SEC) == 0) { - obj->efile.data = data; - obj->efile.data_shndx = idx; + sec_desc->sec_type = SEC_DATA; + sec_desc->shdr = sh; + sec_desc->data = data; } else if (strcmp(name, RODATA_SEC) == 0) { - obj->efile.rodata = data; - obj->efile.rodata_shndx = idx; + sec_desc->sec_type = SEC_RODATA; + sec_desc->shdr = sh; + sec_desc->data = data; } else if (strcmp(name, STRUCT_OPS_SEC) == 0) { obj->efile.st_ops_data = data; obj->efile.st_ops_shndx = idx; @@ -3226,33 +3232,25 @@ static int bpf_object__elf_collect(struct bpf_object *obj) idx, name); } } else if (sh->sh_type == SHT_REL) { - int nr_sects = obj->efile.nr_reloc_sects; - void *sects = obj->efile.reloc_sects; - int sec = sh->sh_info; /* points to other section */ + int targ_sec_idx = sh->sh_info; /* points to other section */ /* Only do relo for section with exec instructions */ - if (!section_have_execinstr(obj, sec) && + if (!section_have_execinstr(obj, targ_sec_idx) && strcmp(name, ".rel" STRUCT_OPS_SEC) && strcmp(name, ".rel" MAPS_ELF_SEC)) { pr_info("elf: skipping relo section(%d) %s for section(%d) %s\n", - idx, name, sec, - elf_sec_name(obj, elf_sec_by_idx(obj, sec)) ?: "<?>"); + idx, name, targ_sec_idx, + elf_sec_name(obj, elf_sec_by_idx(obj, targ_sec_idx)) ?: "<?>"); continue; } - sects = libbpf_reallocarray(sects, nr_sects + 1, - sizeof(*obj->efile.reloc_sects)); - if (!sects) - return -ENOMEM; - - obj->efile.reloc_sects = sects; - obj->efile.nr_reloc_sects++; - - obj->efile.reloc_sects[nr_sects].shdr = sh; - obj->efile.reloc_sects[nr_sects].data = data; + sec_desc->sec_type = SEC_RELO; + sec_desc->shdr = sh; + sec_desc->data = data; } else if (sh->sh_type == SHT_NOBITS && strcmp(name, BSS_SEC) == 0) { - obj->efile.bss = data; - obj->efile.bss_shndx = idx; + sec_desc->sec_type = SEC_BSS; + sec_desc->shdr = sh; + sec_desc->data = data; } else { pr_info("elf: skipping section(%d) %s (size %zu)\n", idx, name, (size_t)sh->sh_size); @@ -3732,9 +3730,14 @@ bpf_object__find_program_by_name(const struct bpf_object *obj, static bool bpf_object__shndx_is_data(const struct bpf_object *obj, int shndx) { - return shndx == obj->efile.data_shndx || - shndx == obj->efile.bss_shndx || - shndx == obj->efile.rodata_shndx; + switch (obj->efile.secs[shndx].sec_type) { + case SEC_BSS: + case SEC_DATA: + case SEC_RODATA: + return true; + default: + return false; + } } static bool bpf_object__shndx_is_maps(const struct bpf_object *obj, @@ -3747,16 +3750,19 @@ static bool bpf_object__shndx_is_maps(const struct bpf_object *obj, static enum libbpf_map_type bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx) { - if (shndx == obj->efile.data_shndx) - return LIBBPF_MAP_DATA; - else if (shndx == obj->efile.bss_shndx) + if (shndx == obj->efile.symbols_shndx) + return LIBBPF_MAP_KCONFIG; + + switch (obj->efile.secs[shndx].sec_type) { + case SEC_BSS: return LIBBPF_MAP_BSS; - else if (shndx == obj->efile.rodata_shndx) + case SEC_DATA: + return LIBBPF_MAP_DATA; + case SEC_RODATA: return LIBBPF_MAP_RODATA; - else if (shndx == obj->efile.symbols_shndx) - return LIBBPF_MAP_KCONFIG; - else + default: return LIBBPF_MAP_UNSPEC; + } } static int bpf_program__record_reloc(struct bpf_program *prog, @@ -3892,7 +3898,7 @@ static int bpf_program__record_reloc(struct bpf_program *prog, } for (map_idx = 0; map_idx < nr_maps; map_idx++) { map = &obj->maps[map_idx]; - if (map->libbpf_type != type) + if (map->libbpf_type != type || map->sec_idx != sym->st_shndx) continue; pr_debug("prog '%s': found data map %zd (%s, sec %d, off %zu) for insn %u\n", prog->name, map_idx, map->name, map->sec_idx, @@ -6205,10 +6211,18 @@ static int bpf_object__collect_relos(struct bpf_object *obj) { int i, err; - for (i = 0; i < obj->efile.nr_reloc_sects; i++) { - Elf64_Shdr *shdr = obj->efile.reloc_sects[i].shdr; - Elf_Data *data = obj->efile.reloc_sects[i].data; - int idx = shdr->sh_info; + for (i = 0; i < obj->efile.sec_cnt; i++) { + struct elf_sec_desc *sec_desc = &obj->efile.secs[i]; + Elf64_Shdr *shdr; + Elf_Data *data; + int idx; + + if (sec_desc->sec_type != SEC_RELO) + continue; + + shdr = sec_desc->shdr; + data = sec_desc->data; + idx = shdr->sh_info; if (shdr->sh_type != SHT_REL) { pr_warn("internal error at %d\n", __LINE__); @@ -6331,6 +6345,7 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, char *license, __u32 kern_version, int *pfd) { struct bpf_prog_load_params load_attr = {}; + struct bpf_object *obj = prog->obj; char *cp, errmsg[STRERR_BUFSIZE]; size_t log_buf_size = 0; char *log_buf = NULL; @@ -6351,7 +6366,7 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, load_attr.prog_type = prog->type; load_attr.expected_attach_type = prog->expected_attach_type; - if (kernel_supports(prog->obj, FEAT_PROG_NAME)) + if (kernel_supports(obj, FEAT_PROG_NAME)) load_attr.name = prog->name; load_attr.insns = insns; load_attr.insn_cnt = insns_cnt; @@ -6364,8 +6379,8 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, load_attr.prog_ifindex = prog->prog_ifindex; /* specify func_info/line_info only if kernel supports them */ - btf_fd = bpf_object__btf_fd(prog->obj); - if (btf_fd >= 0 && kernel_supports(prog->obj, FEAT_BTF_FUNC)) { + btf_fd = bpf_object__btf_fd(obj); + if (btf_fd >= 0 && kernel_supports(obj, FEAT_BTF_FUNC)) { load_attr.prog_btf_fd = btf_fd; load_attr.func_info = prog->func_info; load_attr.func_info_rec_size = prog->func_info_rec_size; @@ -6376,7 +6391,7 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, } load_attr.log_level = prog->log_level; load_attr.prog_flags = prog->prog_flags; - load_attr.fd_array = prog->obj->fd_array; + load_attr.fd_array = obj->fd_array; /* adjust load_attr if sec_def provides custom preload callback */ if (prog->sec_def && prog->sec_def->preload_fn) { @@ -6388,9 +6403,9 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, } } - if (prog->obj->gen_loader) { - bpf_gen__prog_load(prog->obj->gen_loader, &load_attr, - prog - prog->obj->programs); + if (obj->gen_loader) { + bpf_gen__prog_load(obj->gen_loader, &load_attr, + prog - obj->programs); *pfd = -1; return 0; } @@ -6411,16 +6426,21 @@ retry_load: if (log_buf && load_attr.log_level) pr_debug("verifier log:\n%s", log_buf); - if (prog->obj->rodata_map_idx >= 0 && - kernel_supports(prog->obj, FEAT_PROG_BIND_MAP)) { - struct bpf_map *rodata_map = - &prog->obj->maps[prog->obj->rodata_map_idx]; + if (obj->has_rodata && kernel_supports(obj, FEAT_PROG_BIND_MAP)) { + struct bpf_map *map; + int i; + + for (i = 0; i < obj->nr_maps; i++) { + map = &prog->obj->maps[i]; + if (map->libbpf_type != LIBBPF_MAP_RODATA) + continue; - if (bpf_prog_bind_map(ret, bpf_map__fd(rodata_map), NULL)) { - cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); - pr_warn("prog '%s': failed to bind .rodata map: %s\n", - prog->name, cp); - /* Don't fail hard if can't bind rodata. */ + if (bpf_prog_bind_map(ret, bpf_map__fd(map), NULL)) { + cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); + pr_warn("prog '%s': failed to bind .rodata map: %s\n", + prog->name, cp); + /* Don't fail hard if can't bind rodata. */ + } } } |