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| author | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2022-08-02 10:06:12 -0700 |
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2022-08-02 10:06:12 -0700 |
| commit | 8bb5e7f4dcd9b9ef22a3ea25c9066a8a968f12dd (patch) | |
| tree | 0f1383880607a227142f9388a066959926233ff1 /tools/lib/bpf/libbpf.c | |
| parent | 2a96271fb66c499e4a89d76a89d3d01170c10bef (diff) | |
| parent | 7c744d00990ea999d27f306f6db5ccb61b1304b2 (diff) | |
| download | linux-8bb5e7f4dcd9b9ef22a3ea25c9066a8a968f12dd.tar.gz linux-8bb5e7f4dcd9b9ef22a3ea25c9066a8a968f12dd.tar.bz2 linux-8bb5e7f4dcd9b9ef22a3ea25c9066a8a968f12dd.zip | |
Merge branch 'next' into for-linus
Prepare input updates for 5.20 (or 6.0) merge window.
Diffstat (limited to 'tools/lib/bpf/libbpf.c')
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 2183 |
1 files changed, 1790 insertions, 393 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 7f10dd501a52..e89cc9c885b3 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -156,14 +156,6 @@ enum libbpf_strict_mode libbpf_mode = LIBBPF_STRICT_NONE; int libbpf_set_strict_mode(enum libbpf_strict_mode mode) { - /* __LIBBPF_STRICT_LAST is the last power-of-2 value used + 1, so to - * get all possible values we compensate last +1, and then (2*x - 1) - * to get the bit mask - */ - if (mode != LIBBPF_STRICT_ALL - && (mode & ~((__LIBBPF_STRICT_LAST - 1) * 2 - 1))) - return errno = EINVAL, -EINVAL; - libbpf_mode = mode; return 0; } @@ -209,12 +201,6 @@ struct reloc_desc { }; }; -struct bpf_sec_def; - -typedef int (*init_fn_t)(struct bpf_program *prog, long cookie); -typedef int (*preload_fn_t)(struct bpf_program *prog, struct bpf_prog_load_opts *opts, long cookie); -typedef struct bpf_link *(*attach_fn_t)(const struct bpf_program *prog, long cookie); - /* stored as sec_def->cookie for all libbpf-supported SEC()s */ enum sec_def_flags { SEC_NONE = 0, @@ -235,17 +221,22 @@ enum sec_def_flags { SEC_SLEEPABLE = 8, /* allow non-strict prefix matching */ SEC_SLOPPY_PFX = 16, + /* BPF program support non-linear XDP buffer */ + SEC_XDP_FRAGS = 32, + /* deprecated sec definitions not supposed to be used */ + SEC_DEPRECATED = 64, }; struct bpf_sec_def { - const char *sec; + char *sec; enum bpf_prog_type prog_type; enum bpf_attach_type expected_attach_type; long cookie; + int handler_id; - init_fn_t init_fn; - preload_fn_t preload_fn; - attach_fn_t attach_fn; + libbpf_prog_setup_fn_t prog_setup_fn; + libbpf_prog_prepare_load_fn_t prog_prepare_load_fn; + libbpf_prog_attach_fn_t prog_attach_fn; }; /* @@ -311,7 +302,7 @@ struct bpf_program { void *priv; bpf_program_clear_priv_t clear_priv; - bool load; + bool autoload; bool mark_btf_static; enum bpf_prog_type type; enum bpf_attach_type expected_attach_type; @@ -366,6 +357,7 @@ enum libbpf_map_type { }; struct bpf_map { + struct bpf_object *obj; char *name; /* real_name is defined for special internal maps (.rodata*, * .data*, .bss, .kconfig) and preserves their original ELF section @@ -395,7 +387,7 @@ struct bpf_map { char *pin_path; bool pinned; bool reused; - bool skipped; + bool autocreate; __u64 map_extra; }; @@ -492,6 +484,8 @@ struct elf_state { int st_ops_shndx; }; +struct usdt_manager; + struct bpf_object { char name[BPF_OBJ_NAME_LEN]; char license[64]; @@ -554,6 +548,8 @@ struct bpf_object { size_t fd_array_cap; size_t fd_array_cnt; + struct usdt_manager *usdt_man; + char path[]; }; @@ -677,7 +673,18 @@ bpf_object__init_prog(struct bpf_object *obj, struct bpf_program *prog, prog->insns_cnt = prog->sec_insn_cnt; prog->type = BPF_PROG_TYPE_UNSPEC; - prog->load = true; + + /* libbpf's convention for SEC("?abc...") is that it's just like + * SEC("abc...") but the corresponding bpf_program starts out with + * autoload set to false. + */ + if (sec_name[0] == '?') { + prog->autoload = false; + /* from now on forget there was ? in section name */ + sec_name++; + } else { + prog->autoload = true; + } prog->instances.fds = NULL; prog->instances.nr = -1; @@ -1227,10 +1234,8 @@ static void bpf_object__elf_finish(struct bpf_object *obj) if (!obj->efile.elf) return; - if (obj->efile.elf) { - elf_end(obj->efile.elf); - obj->efile.elf = NULL; - } + elf_end(obj->efile.elf); + obj->efile.elf = NULL; obj->efile.symbols = NULL; obj->efile.st_ops_data = NULL; @@ -1378,22 +1383,20 @@ 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) return -EINVAL; scn = elf_sec_by_name(obj, name); data = elf_sec_data(obj, scn); if (data) { - ret = 0; /* found it */ *size = data->d_size; + return 0; /* found it */ } - return *size ? 0 : ret; + return -ENOENT; } static int find_elf_var_offset(const struct bpf_object *obj, const char *name, __u32 *off) @@ -1408,8 +1411,11 @@ static int find_elf_var_offset(const struct bpf_object *obj, const char *name, _ for (si = 0; si < symbols->d_size / sizeof(Elf64_Sym); si++) { Elf64_Sym *sym = elf_sym_by_idx(obj, si); - if (ELF64_ST_BIND(sym->st_info) != STB_GLOBAL || - ELF64_ST_TYPE(sym->st_info) != STT_OBJECT) + if (ELF64_ST_TYPE(sym->st_info) != STT_OBJECT) + continue; + + if (ELF64_ST_BIND(sym->st_info) != STB_GLOBAL && + ELF64_ST_BIND(sym->st_info) != STB_WEAK) continue; sname = elf_sym_str(obj, sym->st_name); @@ -1428,36 +1434,21 @@ static int find_elf_var_offset(const struct bpf_object *obj, const char *name, _ static struct bpf_map *bpf_object__add_map(struct bpf_object *obj) { - struct bpf_map *new_maps; - size_t new_cap; - int i; - - if (obj->nr_maps < obj->maps_cap) - return &obj->maps[obj->nr_maps++]; - - new_cap = max((size_t)4, obj->maps_cap * 3 / 2); - new_maps = libbpf_reallocarray(obj->maps, new_cap, sizeof(*obj->maps)); - if (!new_maps) { - pr_warn("alloc maps for object failed\n"); - return ERR_PTR(-ENOMEM); - } + struct bpf_map *map; + int err; - obj->maps_cap = new_cap; - obj->maps = new_maps; + err = libbpf_ensure_mem((void **)&obj->maps, &obj->maps_cap, + sizeof(*obj->maps), obj->nr_maps + 1); + if (err) + return ERR_PTR(err); - /* zero out new maps */ - memset(obj->maps + obj->nr_maps, 0, - (obj->maps_cap - obj->nr_maps) * sizeof(*obj->maps)); - /* - * fill all fd with -1 so won't close incorrect fd (fd=0 is stdin) - * when failure (zclose won't close negative fd)). - */ - for (i = obj->nr_maps; i < obj->maps_cap; i++) { - obj->maps[i].fd = -1; - obj->maps[i].inner_map_fd = -1; - } + map = &obj->maps[obj->nr_maps++]; + map->obj = obj; + map->fd = -1; + map->inner_map_fd = -1; + map->autocreate = true; - return &obj->maps[obj->nr_maps++]; + return map; } static size_t bpf_map_mmap_sz(const struct bpf_map *map) @@ -1529,6 +1520,9 @@ static char *internal_map_name(struct bpf_object *obj, const char *real_name) } static int +bpf_map_find_btf_info(struct bpf_object *obj, struct bpf_map *map); + +static int bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type, const char *real_name, int sec_idx, void *data, size_t data_sz) { @@ -1575,6 +1569,9 @@ bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type, return err; } + /* failures are fine because of maps like .rodata.str1.1 */ + (void) bpf_map_find_btf_info(obj, map); + if (data) memcpy(map->mmaped, data, data_sz); @@ -1937,6 +1934,11 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict) if (obj->efile.maps_shndx < 0) return 0; + if (libbpf_mode & LIBBPF_STRICT_MAP_DEFINITIONS) { + pr_warn("legacy map definitions in SEC(\"maps\") are not supported\n"); + return -EOPNOTSUPP; + } + if (!symbols) return -EINVAL; @@ -1999,6 +2001,8 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict) return -LIBBPF_ERRNO__FORMAT; } + pr_warn("map '%s' (legacy): legacy map definitions are deprecated, use BTF-defined maps instead\n", map_name); + if (ELF64_ST_BIND(sym->st_info) == STB_LOCAL) { pr_warn("map '%s' (legacy): static maps are not supported\n", map_name); return -ENOTSUP; @@ -2050,6 +2054,9 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict) } memcpy(&map->def, def, sizeof(struct bpf_map_def)); } + + /* btf info may not exist but fill it in if it does exist */ + (void) bpf_map_find_btf_info(obj, map); } return 0; } @@ -2538,6 +2545,10 @@ static int bpf_object__init_user_btf_map(struct bpf_object *obj, fill_map_from_def(map->inner_map, &inner_def); } + err = bpf_map_find_btf_info(obj, map); + if (err) + return err; + return 0; } @@ -2740,6 +2751,9 @@ static int bpf_object__init_btf(struct bpf_object *obj, btf__set_pointer_size(obj->btf, 8); } if (btf_ext_data) { + struct btf_ext_info *ext_segs[3]; + int seg_num, sec_num; + if (!obj->btf) { pr_debug("Ignore ELF section %s because its depending ELF section %s is not found.\n", BTF_EXT_ELF_SEC, BTF_ELF_SEC); @@ -2753,6 +2767,43 @@ static int bpf_object__init_btf(struct bpf_object *obj, obj->btf_ext = NULL; goto out; } + + /* setup .BTF.ext to ELF section mapping */ + ext_segs[0] = &obj->btf_ext->func_info; + ext_segs[1] = &obj->btf_ext->line_info; + ext_segs[2] = &obj->btf_ext->core_relo_info; + for (seg_num = 0; seg_num < ARRAY_SIZE(ext_segs); seg_num++) { + struct btf_ext_info *seg = ext_segs[seg_num]; + const struct btf_ext_info_sec *sec; + const char *sec_name; + Elf_Scn *scn; + + if (seg->sec_cnt == 0) + continue; + + seg->sec_idxs = calloc(seg->sec_cnt, sizeof(*seg->sec_idxs)); + if (!seg->sec_idxs) { + err = -ENOMEM; + goto out; + } + + sec_num = 0; + for_each_btf_ext_sec(seg, sec) { + /* preventively increment index to avoid doing + * this before every continue below + */ + sec_num++; + + sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off); + if (str_is_empty(sec_name)) + continue; + scn = elf_sec_by_name(obj, sec_name); + if (!scn) + continue; + + seg->sec_idxs[sec_num - 1] = elf_ndxscn(scn); + } + } } out: if (err && libbpf_needs_btf(obj)) { @@ -2792,7 +2843,7 @@ static int btf_fixup_datasec(struct bpf_object *obj, struct btf *btf, goto sort_vars; ret = find_elf_sec_sz(obj, name, &size); - if (ret || !size || (t->size && t->size != size)) { + if (ret || !size) { pr_debug("Invalid size for section %s: %u bytes\n", name, size); return -ENOENT; } @@ -2911,7 +2962,7 @@ static bool obj_needs_vmlinux_btf(const struct bpf_object *obj) } bpf_object__for_each_program(prog, obj) { - if (!prog->load) + if (!prog->autoload) continue; if (prog_needs_vmlinux_btf(prog)) return true; @@ -3836,7 +3887,14 @@ static bool prog_is_subprog(const struct bpf_object *obj, * .text programs are subprograms (even if they are not called from * other programs), because libbpf never explicitly supported mixing * SEC()-designated BPF programs and .text entry-point BPF programs. + * + * In libbpf 1.0 strict mode, we always consider .text + * programs to be subprograms. */ + + if (libbpf_mode & LIBBPF_STRICT_SEC_NAME) + return prog->sec_idx == obj->efile.text_shndx; + return prog->sec_idx == obj->efile.text_shndx && obj->nr_programs > 1; } @@ -4181,6 +4239,9 @@ static int bpf_map_find_btf_info(struct bpf_object *obj, struct bpf_map *map) __u32 key_type_id = 0, value_type_id = 0; int ret; + if (!obj->btf) + return -ENOENT; + /* if it's BTF-defined map, we don't need to search for type IDs. * For struct_ops map, it does not need btf_key_type_id and * btf_value_type_id. @@ -4190,9 +4251,13 @@ static int bpf_map_find_btf_info(struct bpf_object *obj, struct bpf_map *map) return 0; if (!bpf_map__is_internal(map)) { + pr_warn("Use of BPF_ANNOTATE_KV_PAIR is deprecated, use BTF-defined maps in .maps section instead\n"); +#pragma GCC diagnostic push +#pragma GCC diagnostic ignored "-Wdeprecated-declarations" ret = btf__get_map_kv_tids(obj->btf, map->name, def->key_size, def->value_size, &key_type_id, &value_type_id); +#pragma GCC diagnostic pop } else { /* * LLVM annotates global data differently in BTF, that is, @@ -4245,6 +4310,20 @@ static int bpf_get_map_info_from_fdinfo(int fd, struct bpf_map_info *info) return 0; } +bool bpf_map__autocreate(const struct bpf_map *map) +{ + return map->autocreate; +} + +int bpf_map__set_autocreate(struct bpf_map *map, bool autocreate) +{ + if (map->obj->loaded) + return libbpf_err(-EBUSY); + + map->autocreate = autocreate; + return 0; +} + int bpf_map__reuse_fd(struct bpf_map *map, int fd) { struct bpf_map_info info = {}; @@ -4564,7 +4643,7 @@ static int probe_kern_probe_read_kernel(void) }; int fd, insn_cnt = ARRAY_SIZE(insns); - fd = bpf_prog_load(BPF_PROG_TYPE_KPROBE, NULL, "GPL", insns, insn_cnt, NULL); + fd = bpf_prog_load(BPF_PROG_TYPE_TRACEPOINT, NULL, "GPL", insns, insn_cnt, NULL); return probe_fd(fd); } @@ -4655,6 +4734,18 @@ static int probe_perf_link(void) return link_fd < 0 && err == -EBADF; } +static int probe_kern_bpf_cookie(void) +{ + struct bpf_insn insns[] = { + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_attach_cookie), + BPF_EXIT_INSN(), + }; + int ret, insn_cnt = ARRAY_SIZE(insns); + + ret = bpf_prog_load(BPF_PROG_TYPE_KPROBE, NULL, "GPL", insns, insn_cnt, NULL); + return probe_fd(ret); +} + enum kern_feature_result { FEAT_UNKNOWN = 0, FEAT_SUPPORTED = 1, @@ -4717,6 +4808,9 @@ static struct kern_feature_desc { [FEAT_MEMCG_ACCOUNT] = { "memcg-based memory accounting", probe_memcg_account, }, + [FEAT_BPF_COOKIE] = { + "BPF cookie support", probe_kern_bpf_cookie, + }, }; bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id) @@ -4800,8 +4894,8 @@ bpf_object__reuse_map(struct bpf_map *map) } err = bpf_map__reuse_fd(map, pin_fd); + close(pin_fd); if (err) { - close(pin_fd); return err; } map->pinned = true; @@ -4849,12 +4943,47 @@ bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map) static void bpf_map__destroy(struct bpf_map *map); +static bool is_pow_of_2(size_t x) +{ + return x && (x & (x - 1)); +} + +static size_t adjust_ringbuf_sz(size_t sz) +{ + __u32 page_sz = sysconf(_SC_PAGE_SIZE); + __u32 mul; + + /* if user forgot to set any size, make sure they see error */ + if (sz == 0) + return 0; + /* Kernel expects BPF_MAP_TYPE_RINGBUF's max_entries to be + * a power-of-2 multiple of kernel's page size. If user diligently + * satisified these conditions, pass the size through. + */ + if ((sz % page_sz) == 0 && is_pow_of_2(sz / page_sz)) + return sz; + + /* Otherwise find closest (page_sz * power_of_2) product bigger than + * user-set size to satisfy both user size request and kernel + * requirements and substitute correct max_entries for map creation. + */ + for (mul = 1; mul <= UINT_MAX / page_sz; mul <<= 1) { + if (mul * page_sz > sz) + return mul * page_sz; + } + + /* if it's impossible to satisfy the conditions (i.e., user size is + * very close to UINT_MAX but is not a power-of-2 multiple of + * page_size) then just return original size and let kernel reject it + */ + return sz; +} + static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, bool is_inner) { LIBBPF_OPTS(bpf_map_create_opts, create_attr); struct bpf_map_def *def = &map->def; const char *map_name = NULL; - __u32 max_entries; int err = 0; if (kernel_supports(obj, FEAT_PROG_NAME)) @@ -4864,25 +4993,10 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b create_attr.numa_node = map->numa_node; create_attr.map_extra = map->map_extra; - if (def->type == BPF_MAP_TYPE_PERF_EVENT_ARRAY && !def->max_entries) { - int nr_cpus; - - nr_cpus = libbpf_num_possible_cpus(); - if (nr_cpus < 0) { - pr_warn("map '%s': failed to determine number of system CPUs: %d\n", - map->name, nr_cpus); - return nr_cpus; - } - pr_debug("map '%s': setting size to %d\n", map->name, nr_cpus); - max_entries = nr_cpus; - } else { - max_entries = def->max_entries; - } - if (bpf_map__is_struct_ops(map)) create_attr.btf_vmlinux_value_type_id = map->btf_vmlinux_value_type_id; - if (obj->btf && btf__fd(obj->btf) >= 0 && !bpf_map_find_btf_info(obj, map)) { + if (obj->btf && btf__fd(obj->btf) >= 0) { create_attr.btf_fd = btf__fd(obj->btf); create_attr.btf_key_type_id = map->btf_key_type_id; create_attr.btf_value_type_id = map->btf_value_type_id; @@ -4903,6 +5017,9 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b } switch (def->type) { + case BPF_MAP_TYPE_RINGBUF: + map->def.max_entries = adjust_ringbuf_sz(map->def.max_entries); + /* fallthrough */ case BPF_MAP_TYPE_PERF_EVENT_ARRAY: case BPF_MAP_TYPE_CGROUP_ARRAY: case BPF_MAP_TYPE_STACK_TRACE: @@ -4916,7 +5033,6 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b case BPF_MAP_TYPE_SOCKHASH: case BPF_MAP_TYPE_QUEUE: case BPF_MAP_TYPE_STACK: - case BPF_MAP_TYPE_RINGBUF: create_attr.btf_fd = 0; create_attr.btf_key_type_id = 0; create_attr.btf_value_type_id = 0; @@ -4928,7 +5044,7 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b if (obj->gen_loader) { bpf_gen__map_create(obj->gen_loader, def->type, map_name, - def->key_size, def->value_size, max_entries, + def->key_size, def->value_size, def->max_entries, &create_attr, is_inner ? -1 : map - obj->maps); /* Pretend to have valid FD to pass various fd >= 0 checks. * This fd == 0 will not be used with any syscall and will be reset to -1 eventually. @@ -4937,7 +5053,7 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b } else { map->fd = bpf_map_create(def->type, map_name, def->key_size, def->value_size, - max_entries, &create_attr); + def->max_entries, &create_attr); } if (map->fd < 0 && (create_attr.btf_key_type_id || create_attr.btf_value_type_id)) { @@ -4954,7 +5070,7 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b map->btf_value_type_id = 0; map->fd = bpf_map_create(def->type, map_name, def->key_size, def->value_size, - max_entries, &create_attr); + def->max_entries, &create_attr); } err = map->fd < 0 ? -errno : 0; @@ -5058,6 +5174,24 @@ static int bpf_object_init_prog_arrays(struct bpf_object *obj) return 0; } +static int map_set_def_max_entries(struct bpf_map *map) +{ + if (map->def.type == BPF_MAP_TYPE_PERF_EVENT_ARRAY && !map->def.max_entries) { + int nr_cpus; + + nr_cpus = libbpf_num_possible_cpus(); + if (nr_cpus < 0) { + pr_warn("map '%s': failed to determine number of system CPUs: %d\n", + map->name, nr_cpus); + return nr_cpus; + } + pr_debug("map '%s': setting size to %d\n", map->name, nr_cpus); + map->def.max_entries = nr_cpus; + } + + return 0; +} + static int bpf_object__create_maps(struct bpf_object *obj) { @@ -5084,12 +5218,18 @@ bpf_object__create_maps(struct bpf_object *obj) * bpf_object loading will succeed just fine even on old * kernels. */ - if (bpf_map__is_internal(map) && - !kernel_supports(obj, FEAT_GLOBAL_DATA)) { - map->skipped = true; + if (bpf_map__is_internal(map) && !kernel_supports(obj, FEAT_GLOBAL_DATA)) + map->autocreate = false; + + if (!map->autocreate) { + pr_debug("map '%s': skipped auto-creating...\n", map->name); continue; } + err = map_set_def_max_entries(map); + if (err) + goto err_out; + retried = false; retry: if (map->pin_path) { @@ -5185,18 +5325,21 @@ size_t bpf_core_essential_name_len(const char *name) return n; } -static void bpf_core_free_cands(struct bpf_core_cand_list *cands) +void bpf_core_free_cands(struct bpf_core_cand_list *cands) { + if (!cands) + return; + free(cands->cands); free(cands); } -static int bpf_core_add_cands(struct bpf_core_cand *local_cand, - size_t local_essent_len, - const struct btf *targ_btf, - const char *targ_btf_name, - int targ_start_id, - struct bpf_core_cand_list *cands) +int bpf_core_add_cands(struct bpf_core_cand *local_cand, + size_t local_essent_len, + const struct btf *targ_btf, + const char *targ_btf_name, + int targ_start_id, + struct bpf_core_cand_list *cands) { struct bpf_core_cand *new_cands, *cand; const struct btf_type *t, *local_t; @@ -5523,11 +5666,28 @@ static int record_relo_core(struct bpf_program *prog, return 0; } -static int bpf_core_apply_relo(struct bpf_program *prog, - const struct bpf_core_relo *relo, - int relo_idx, - const struct btf *local_btf, - struct hashmap *cand_cache) +static const struct bpf_core_relo *find_relo_core(struct bpf_program *prog, int insn_idx) +{ + struct reloc_desc *relo; + int i; + + for (i = 0; i < prog->nr_reloc; i++) { + relo = &prog->reloc_desc[i]; + if (relo->type != RELO_CORE || relo->insn_idx != insn_idx) + continue; + + return relo->core_relo; + } + + return NULL; +} + +static int bpf_core_resolve_relo(struct bpf_program *prog, + const struct bpf_core_relo *relo, + int relo_idx, + const struct btf *local_btf, + struct hashmap *cand_cache, + struct bpf_core_relo_res *targ_res) { struct bpf_core_spec specs_scratch[3] = {}; const void *type_key = u32_as_hash_key(relo->type_id); @@ -5536,20 +5696,7 @@ static int bpf_core_apply_relo(struct bpf_program *prog, const struct btf_type *local_type; const char *local_name; __u32 local_id = relo->type_id; - struct bpf_insn *insn; - int insn_idx, err; - - if (relo->insn_off % BPF_INSN_SZ) - return -EINVAL; - insn_idx = relo->insn_off / BPF_INSN_SZ; - /* adjust insn_idx from section frame of reference to the local - * program's frame of reference; (sub-)program code is not yet - * relocated, so it's enough to just subtract in-section offset - */ - insn_idx = insn_idx - prog->sec_insn_off; - if (insn_idx >= prog->insns_cnt) - return -EINVAL; - insn = &prog->insns[insn_idx]; + int err; local_type = btf__type_by_id(local_btf, local_id); if (!local_type) @@ -5559,15 +5706,6 @@ static int bpf_core_apply_relo(struct bpf_program *prog, if (!local_name) return -EINVAL; - if (prog->obj->gen_loader) { - const char *spec_str = btf__name_by_offset(local_btf, relo->access_str_off); - - pr_debug("record_relo_core: prog %td insn[%d] %s %s %s final insn_idx %d\n", - prog - prog->obj->programs, relo->insn_off / 8, - btf_kind_str(local_type), local_name, spec_str, insn_idx); - return record_relo_core(prog, relo, insn_idx); - } - if (relo->kind != BPF_CORE_TYPE_ID_LOCAL && !hashmap__find(cand_cache, type_key, (void **)&cands)) { cands = bpf_core_find_cands(prog->obj, local_btf, local_id); @@ -5584,21 +5722,23 @@ static int bpf_core_apply_relo(struct bpf_program *prog, } } - return bpf_core_apply_relo_insn(prog_name, insn, insn_idx, relo, - relo_idx, local_btf, cands, specs_scratch); + return bpf_core_calc_relo_insn(prog_name, relo, relo_idx, local_btf, cands, specs_scratch, + targ_res); } static int bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path) { const struct btf_ext_info_sec *sec; + struct bpf_core_relo_res targ_res; const struct bpf_core_relo *rec; const struct btf_ext_info *seg; struct hashmap_entry *entry; struct hashmap *cand_cache = NULL; struct bpf_program *prog; + struct bpf_insn *insn; const char *sec_name; - int i, err = 0, insn_idx, sec_idx; + int i, err = 0, insn_idx, sec_idx, sec_num; if (obj->btf_ext->core_relo_info.len == 0) return 0; @@ -5619,54 +5759,75 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path) } seg = &obj->btf_ext->core_relo_info; + sec_num = 0; for_each_btf_ext_sec(seg, sec) { + sec_idx = seg->sec_idxs[sec_num]; + sec_num++; + sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off); if (str_is_empty(sec_name)) { err = -EINVAL; goto out; } - /* bpf_object's ELF is gone by now so it's not easy to find - * section index by section name, but we can find *any* - * bpf_program within desired section name and use it's - * prog->sec_idx to do a proper search by section index and - * instruction offset - */ - prog = NULL; - for (i = 0; i < obj->nr_programs; i++) { - prog = &obj->programs[i]; - if (strcmp(prog->sec_name, sec_name) == 0) - break; - } - if (!prog) { - pr_warn("sec '%s': failed to find a BPF program\n", sec_name); - return -ENOENT; - } - sec_idx = prog->sec_idx; - pr_debug("sec '%s': found %d CO-RE relocations\n", - sec_name, sec->num_info); + pr_debug("sec '%s': found %d CO-RE relocations\n", sec_name, sec->num_info); for_each_btf_ext_rec(seg, sec, i, rec) { + if (rec->insn_off % BPF_INSN_SZ) + return -EINVAL; insn_idx = rec->insn_off / BPF_INSN_SZ; prog = find_prog_by_sec_insn(obj, sec_idx, insn_idx); if (!prog) { - pr_warn("sec '%s': failed to find program at insn #%d for CO-RE offset relocation #%d\n", - sec_name, insn_idx, i); - err = -EINVAL; - goto out; + /* When __weak subprog is "overridden" by another instance + * of the subprog from a different object file, linker still + * appends all the .BTF.ext info that used to belong to that + * eliminated subprogram. + * This is similar to what x86-64 linker does for relocations. + * So just ignore such relocations just like we ignore + * subprog instructions when discovering subprograms. + */ + pr_debug("sec '%s': skipping CO-RE relocation #%d for insn #%d belonging to eliminated weak subprogram\n", + sec_name, i, insn_idx); + continue; } /* no need to apply CO-RE relocation if the program is * not going to be loaded */ - if (!prog->load) + if (!prog->autoload) + continue; + + /* adjust insn_idx from section frame of reference to the local + * program's frame of reference; (sub-)program code is not yet + * relocated, so it's enough to just subtract in-section offset + */ + insn_idx = insn_idx - prog->sec_insn_off; + if (insn_idx >= prog->insns_cnt) + return -EINVAL; + insn = &prog->insns[insn_idx]; + + err = record_relo_core(prog, rec, insn_idx); + if (err) { + pr_warn("prog '%s': relo #%d: failed to record relocation: %d\n", + prog->name, i, err); + goto out; + } + + if (prog->obj->gen_loader) continue; - err = bpf_core_apply_relo(prog, rec, i, obj->btf, cand_cache); + err = bpf_core_resolve_relo(prog, rec, i, obj->btf, cand_cache, &targ_res); if (err) { pr_warn("prog '%s': relo #%d: failed to relocate: %d\n", prog->name, i, err); goto out; } + + err = bpf_core_patch_insn(prog->name, insn, insn_idx, rec, i, &targ_res); + if (err) { + pr_warn("prog '%s': relo #%d: failed to patch insn #%u: %d\n", + prog->name, i, insn_idx, err); + goto out; + } } } @@ -5684,6 +5845,36 @@ out: return err; } +/* base map load ldimm64 special constant, used also for log fixup logic */ +#define MAP_LDIMM64_POISON_BASE 2001000000 +#define MAP_LDIMM64_POISON_PFX "200100" + +static void poison_map_ldimm64(struct bpf_program *prog, int relo_idx, + int insn_idx, struct bpf_insn *insn, + int map_idx, const struct bpf_map *map) +{ + int i; + + pr_debug("prog '%s': relo #%d: poisoning insn #%d that loads map #%d '%s'\n", + prog->name, relo_idx, insn_idx, map_idx, map->name); + + /* we turn single ldimm64 into two identical invalid calls */ + for (i = 0; i < 2; i++) { + insn->code = BPF_JMP | BPF_CALL; + insn->dst_reg = 0; + insn->src_reg = 0; + insn->off = 0; + /* if this instruction is reachable (not a dead code), + * verifier will complain with something like: + * invalid func unknown#2001000123 + * where lower 123 is map index into obj->maps[] array + */ + insn->imm = MAP_LDIMM64_POISON_BASE + map_idx; + + insn++; + } +} + /* Relocate data references within program code: * - map references; * - global variable references; @@ -5697,33 +5888,35 @@ bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog) for (i = 0; i < prog->nr_reloc; i++) { struct reloc_desc *relo = &prog->reloc_desc[i]; struct bpf_insn *insn = &prog->insns[relo->insn_idx]; + const struct bpf_map *map; struct extern_desc *ext; switch (relo->type) { case RELO_LD64: + map = &obj->maps[relo->map_idx]; if (obj->gen_loader) { insn[0].src_reg = BPF_PSEUDO_MAP_IDX; insn[0].imm = relo->map_idx; - } else { + } else if (map->autocreate) { insn[0].src_reg = BPF_PSEUDO_MAP_FD; - insn[0].imm = obj->maps[relo->map_idx].fd; + insn[0].imm = map->fd; + } else { + poison_map_ldimm64(prog, i, relo->insn_idx, insn, + relo->map_idx, map); } break; case RELO_DATA: + map = &obj->maps[relo->map_idx]; insn[1].imm = insn[0].imm + relo->sym_off; if (obj->gen_loader) { insn[0].src_reg = BPF_PSEUDO_MAP_IDX_VALUE; insn[0].imm = relo->map_idx; - } else { - const struct bpf_map *map = &obj->maps[relo->map_idx]; - - if (map->skipped) { - pr_warn("prog '%s': relo #%d: kernel doesn't support global data\n", - prog->name, i); - return -ENOTSUP; - } + } else if (map->autocreate) { insn[0].src_reg = BPF_PSEUDO_MAP_VALUE; - insn[0].imm = obj->maps[relo->map_idx].fd; + insn[0].imm = map->fd; + } else { + poison_map_ldimm64(prog, i, relo->insn_idx, insn, + relo->map_idx, map); } break; case RELO_EXTERN_VAR: @@ -5793,14 +5986,13 @@ static int adjust_prog_btf_ext_info(const struct bpf_object *obj, void *rec, *rec_end, *new_prog_info; const struct btf_ext_info_sec *sec; size_t old_sz, new_sz; - const char *sec_name; - int i, off_adj; + int i, sec_num, sec_idx, off_adj; + sec_num = 0; for_each_btf_ext_sec(ext_info, sec) { - sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off); - if (!sec_name) - return -EINVAL; - if (strcmp(sec_name, prog->sec_name) != 0) + sec_idx = ext_info->sec_idxs[sec_num]; + sec_num++; + if (prog->sec_idx != sec_idx) continue; for_each_btf_ext_rec(ext_info, sec, i, rec) { @@ -6195,7 +6387,6 @@ bpf_object__relocate_calls(struct bpf_object *obj, struct bpf_program *prog) if (err) return err; - return 0; } @@ -6256,8 +6447,7 @@ bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path) err); return err; } - if (obj->gen_loader) - bpf_object__sort_relos(obj); + bpf_object__sort_relos(obj); } /* Before relocating calls pre-process relocations and mark @@ -6293,7 +6483,7 @@ bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path) */ if (prog_is_subprog(obj, prog)) continue; - if (!prog->load) + if (!prog->autoload) continue; err = bpf_object__relocate_calls(obj, prog); @@ -6308,7 +6498,7 @@ bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path) prog = &obj->programs[i]; if (prog_is_subprog(obj, prog)) continue; - if (!prog->load) + if (!prog->autoload) continue; err = bpf_object__relocate_data(obj, prog); if (err) { @@ -6317,8 +6507,7 @@ bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path) return err; } } - if (!obj->gen_loader) - bpf_object__free_relocs(obj); + return 0; } @@ -6549,9 +6738,9 @@ static int bpf_object__sanitize_prog(struct bpf_object *obj, struct bpf_program static int libbpf_find_attach_btf_id(struct bpf_program *prog, const char *attach_name, int *btf_obj_fd, int *btf_type_id); -/* this is called as prog->sec_def->preload_fn for libbpf-supported sec_defs */ -static int libbpf_preload_prog(struct bpf_program *prog, - struct bpf_prog_load_opts *opts, long cookie) +/* this is called as prog->sec_def->prog_prepare_load_fn for libbpf-supported sec_defs */ +static int libbpf_prepare_prog_load(struct bpf_program *prog, + struct bpf_prog_load_opts *opts, long cookie) { enum sec_def_flags def = cookie; @@ -6562,13 +6751,35 @@ static int libbpf_preload_prog(struct bpf_program *prog, if (def & SEC_SLEEPABLE) opts->prog_flags |= BPF_F_SLEEPABLE; - if ((prog->type == BPF_PROG_TYPE_TRACING || - prog->type == BPF_PROG_TYPE_LSM || - prog->type == BPF_PROG_TYPE_EXT) && !prog->attach_btf_id) { + if (prog->type == BPF_PROG_TYPE_XDP && (def & SEC_XDP_FRAGS)) + opts->prog_flags |= BPF_F_XDP_HAS_FRAGS; + + if (def & SEC_DEPRECATED) { + pr_warn("SEC(\"%s\") is deprecated, please see https://github.com/libbpf/libbpf/wiki/Libbpf-1.0-migration-guide#bpf-program-sec-annotation-deprecations for details\n", + prog->sec_name); + } + + if ((def & SEC_ATTACH_BTF) && !prog->attach_btf_id) { int btf_obj_fd = 0, btf_type_id = 0, err; const char *attach_name; - attach_name = str |
