Merge branch 'libbpf-fixes'
Daniel Borkmann says: ==================== Two small fixes in relation to global data handling. Thanks! ==================== Acked-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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commit
0e33d334df
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@ -126,6 +126,8 @@ static inline __u64 ptr_to_u64(const void *ptr)
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struct bpf_capabilities {
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/* v4.14: kernel support for program & map names. */
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__u32 name:1;
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/* v5.2: kernel support for global data sections. */
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__u32 global_data:1;
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};
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/*
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@ -854,12 +856,15 @@ bpf_object__init_maps(struct bpf_object *obj, int flags)
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*
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* TODO: Detect array of map and report error.
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*/
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if (obj->efile.data_shndx >= 0)
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nr_maps_glob++;
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if (obj->efile.rodata_shndx >= 0)
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nr_maps_glob++;
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if (obj->efile.bss_shndx >= 0)
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nr_maps_glob++;
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if (obj->caps.global_data) {
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if (obj->efile.data_shndx >= 0)
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nr_maps_glob++;
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if (obj->efile.rodata_shndx >= 0)
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nr_maps_glob++;
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if (obj->efile.bss_shndx >= 0)
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nr_maps_glob++;
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}
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for (i = 0; data && i < nr_syms; i++) {
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GElf_Sym sym;
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@ -870,14 +875,14 @@ bpf_object__init_maps(struct bpf_object *obj, int flags)
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nr_maps++;
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}
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/* Alloc obj->maps and fill nr_maps. */
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pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path,
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nr_maps, data->d_size);
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if (!nr_maps && !nr_maps_glob)
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return 0;
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/* Assume equally sized map definitions */
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if (data) {
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pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path,
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nr_maps, data->d_size);
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map_def_sz = data->d_size / nr_maps;
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if (!data->d_size || (data->d_size % nr_maps) != 0) {
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pr_warning("unable to determine map definition size "
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@ -971,6 +976,9 @@ bpf_object__init_maps(struct bpf_object *obj, int flags)
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map_idx++;
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}
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if (!obj->caps.global_data)
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goto finalize;
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/*
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* Populate rest of obj->maps with libbpf internal maps.
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*/
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@ -988,6 +996,7 @@ bpf_object__init_maps(struct bpf_object *obj, int flags)
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ret = bpf_object__init_internal_map(obj, &obj->maps[map_idx++],
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LIBBPF_MAP_BSS,
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obj->efile.bss, NULL);
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finalize:
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if (!ret)
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qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]),
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compare_bpf_map);
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@ -1333,11 +1342,17 @@ bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
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if (bpf_object__shndx_is_maps(obj, shdr_idx) ||
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bpf_object__shndx_is_data(obj, shdr_idx)) {
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type = bpf_object__section_to_libbpf_map_type(obj, shdr_idx);
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if (type != LIBBPF_MAP_UNSPEC &&
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GELF_ST_BIND(sym.st_info) == STB_GLOBAL) {
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pr_warning("bpf: relocation: not yet supported relo for non-static global \'%s\' variable found in insns[%d].code 0x%x\n",
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name, insn_idx, insns[insn_idx].code);
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return -LIBBPF_ERRNO__RELOC;
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if (type != LIBBPF_MAP_UNSPEC) {
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if (GELF_ST_BIND(sym.st_info) == STB_GLOBAL) {
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pr_warning("bpf: relocation: not yet supported relo for non-static global \'%s\' variable found in insns[%d].code 0x%x\n",
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name, insn_idx, insns[insn_idx].code);
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return -LIBBPF_ERRNO__RELOC;
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}
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if (!obj->caps.global_data) {
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pr_warning("bpf: relocation: kernel does not support global \'%s\' variable access in insns[%d]\n",
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name, insn_idx);
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return -LIBBPF_ERRNO__RELOC;
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}
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}
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for (map_idx = 0; map_idx < nr_maps; map_idx++) {
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@ -1495,10 +1510,68 @@ bpf_object__probe_name(struct bpf_object *obj)
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return 0;
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}
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static int
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bpf_object__probe_global_data(struct bpf_object *obj)
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{
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struct bpf_load_program_attr prg_attr;
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struct bpf_create_map_attr map_attr;
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char *cp, errmsg[STRERR_BUFSIZE];
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struct bpf_insn insns[] = {
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BPF_LD_MAP_VALUE(BPF_REG_1, 0, 16),
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BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 42),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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};
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int ret, map;
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memset(&map_attr, 0, sizeof(map_attr));
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map_attr.map_type = BPF_MAP_TYPE_ARRAY;
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map_attr.key_size = sizeof(int);
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map_attr.value_size = 32;
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map_attr.max_entries = 1;
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map = bpf_create_map_xattr(&map_attr);
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if (map < 0) {
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cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
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pr_warning("Error in %s():%s(%d). Couldn't create simple array map.\n",
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__func__, cp, errno);
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return -errno;
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}
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insns[0].imm = map;
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memset(&prg_attr, 0, sizeof(prg_attr));
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prg_attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
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prg_attr.insns = insns;
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prg_attr.insns_cnt = ARRAY_SIZE(insns);
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prg_attr.license = "GPL";
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ret = bpf_load_program_xattr(&prg_attr, NULL, 0);
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if (ret >= 0) {
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obj->caps.global_data = 1;
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close(ret);
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}
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close(map);
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return 0;
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}
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static int
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bpf_object__probe_caps(struct bpf_object *obj)
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{
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return bpf_object__probe_name(obj);
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int (*probe_fn[])(struct bpf_object *obj) = {
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bpf_object__probe_name,
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bpf_object__probe_global_data,
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};
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int i, ret;
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for (i = 0; i < ARRAY_SIZE(probe_fn); i++) {
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ret = probe_fn[i](obj);
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if (ret < 0)
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return ret;
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}
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return 0;
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}
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static int
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@ -2100,6 +2173,7 @@ __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz,
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CHECK_ERR(bpf_object__elf_init(obj), err, out);
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CHECK_ERR(bpf_object__check_endianness(obj), err, out);
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CHECK_ERR(bpf_object__probe_caps(obj), err, out);
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CHECK_ERR(bpf_object__elf_collect(obj, flags), err, out);
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CHECK_ERR(bpf_object__collect_reloc(obj), err, out);
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CHECK_ERR(bpf_object__validate(obj, needs_kver), err, out);
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@ -2193,7 +2267,6 @@ int bpf_object__load(struct bpf_object *obj)
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obj->loaded = true;
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CHECK_ERR(bpf_object__probe_caps(obj), err, out);
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CHECK_ERR(bpf_object__create_maps(obj), err, out);
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CHECK_ERR(bpf_object__relocate(obj), err, out);
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CHECK_ERR(bpf_object__load_progs(obj), err, out);
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