From 3d65014146c69bbc4d2947f60dbd722d352cdc46 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Fri, 7 Dec 2018 16:42:31 -0800 Subject: bpf: libbpf: Add btf_line_info support to libbpf This patch adds bpf_line_info support to libbpf: 1) Parsing the line_info sec from ".BTF.ext" 2) Relocating the line_info. If the main prog *_info relocation fails, it will ignore the remaining subprog line_info and continue. If the subprog *_info relocation fails, it will bail out. 3) BPF_PROG_LOAD a prog with line_info Signed-off-by: Martin KaFai Lau Acked-by: Yonghong Song Signed-off-by: Alexei Starovoitov --- tools/lib/bpf/bpf.c | 86 +++++++++++++------- tools/lib/bpf/bpf.h | 3 + tools/lib/bpf/btf.c | 209 +++++++++++++++++++++++++++++++++++-------------- tools/lib/bpf/btf.h | 10 ++- tools/lib/bpf/libbpf.c | 20 +++++ 5 files changed, 239 insertions(+), 89 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 9fbbc0ed5952..3caaa3428774 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -173,11 +173,36 @@ int bpf_create_map_in_map(enum bpf_map_type map_type, const char *name, -1); } +static void * +alloc_zero_tailing_info(const void *orecord, __u32 cnt, + __u32 actual_rec_size, __u32 expected_rec_size) +{ + __u64 info_len = actual_rec_size * cnt; + void *info, *nrecord; + int i; + + info = malloc(info_len); + if (!info) + return NULL; + + /* zero out bytes kernel does not understand */ + nrecord = info; + for (i = 0; i < cnt; i++) { + memcpy(nrecord, orecord, expected_rec_size); + memset(nrecord + expected_rec_size, 0, + actual_rec_size - expected_rec_size); + orecord += actual_rec_size; + nrecord += actual_rec_size; + } + + return info; +} + int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr, char *log_buf, size_t log_buf_sz) { + void *finfo = NULL, *linfo = NULL; union bpf_attr attr; - void *finfo = NULL; __u32 name_len; int fd; @@ -201,6 +226,9 @@ int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr, attr.func_info_rec_size = load_attr->func_info_rec_size; attr.func_info_cnt = load_attr->func_info_cnt; attr.func_info = ptr_to_u64(load_attr->func_info); + attr.line_info_rec_size = load_attr->line_info_rec_size; + attr.line_info_cnt = load_attr->line_info_cnt; + attr.line_info = ptr_to_u64(load_attr->line_info); memcpy(attr.prog_name, load_attr->name, min(name_len, BPF_OBJ_NAME_LEN - 1)); @@ -212,36 +240,35 @@ int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr, * to give user space a hint how to deal with loading failure. * Check to see whether we can make some changes and load again. */ - if (errno == E2BIG && attr.func_info_cnt && - attr.func_info_rec_size < load_attr->func_info_rec_size) { - __u32 actual_rec_size = load_attr->func_info_rec_size; - __u32 expected_rec_size = attr.func_info_rec_size; - __u32 finfo_cnt = load_attr->func_info_cnt; - __u64 finfo_len = actual_rec_size * finfo_cnt; - const void *orecord; - void *nrecord; - int i; - - finfo = malloc(finfo_len); - if (!finfo) - /* further try with log buffer won't help */ - return fd; - - /* zero out bytes kernel does not understand */ - orecord = load_attr->func_info; - nrecord = finfo; - for (i = 0; i < load_attr->func_info_cnt; i++) { - memcpy(nrecord, orecord, expected_rec_size); - memset(nrecord + expected_rec_size, 0, - actual_rec_size - expected_rec_size); - orecord += actual_rec_size; - nrecord += actual_rec_size; + while (errno == E2BIG && (!finfo || !linfo)) { + if (!finfo && attr.func_info_cnt && + attr.func_info_rec_size < load_attr->func_info_rec_size) { + /* try with corrected func info records */ + finfo = alloc_zero_tailing_info(load_attr->func_info, + load_attr->func_info_cnt, + load_attr->func_info_rec_size, + attr.func_info_rec_size); + if (!finfo) + goto done; + + attr.func_info = ptr_to_u64(finfo); + attr.func_info_rec_size = load_attr->func_info_rec_size; + } else if (!linfo && attr.line_info_cnt && + attr.line_info_rec_size < + load_attr->line_info_rec_size) { + linfo = alloc_zero_tailing_info(load_attr->line_info, + load_attr->line_info_cnt, + load_attr->line_info_rec_size, + attr.line_info_rec_size); + if (!linfo) + goto done; + + attr.line_info = ptr_to_u64(linfo); + attr.line_info_rec_size = load_attr->line_info_rec_size; + } else { + break; } - /* try with corrected func info records */ - attr.func_info = ptr_to_u64(finfo); - attr.func_info_rec_size = load_attr->func_info_rec_size; - fd = sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr)); if (fd >= 0) @@ -259,6 +286,7 @@ int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr, fd = sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr)); done: free(finfo); + free(linfo); return fd; } diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index 098e6f793b76..8f09de482839 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -82,6 +82,9 @@ struct bpf_load_program_attr { __u32 func_info_rec_size; const void *func_info; __u32 func_info_cnt; + __u32 line_info_rec_size; + const void *line_info; + __u32 line_info_cnt; }; /* Flags to direct loading requirements */ diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index aa4fa02b13fc..d682d3b8f7b9 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -37,16 +37,26 @@ struct btf { int fd; }; +struct btf_ext_info { + /* + * info points to a deep copy of the individual info section + * (e.g. func_info and line_info) from the .BTF.ext. + * It does not include the __u32 rec_size. + */ + void *info; + __u32 rec_size; + __u32 len; +}; + struct btf_ext { - void *func_info; - __u32 func_info_rec_size; - __u32 func_info_len; + struct btf_ext_info func_info; + struct btf_ext_info line_info; }; -struct btf_sec_func_info { +struct btf_ext_info_sec { __u32 sec_name_off; - __u32 num_func_info; - /* Followed by num_func_info number of bpf func_info records */ + __u32 num_info; + /* Followed by num_info * record_size number of bytes */ __u8 data[0]; }; @@ -56,6 +66,14 @@ struct bpf_func_info_min { __u32 type_id; }; +/* The minimum bpf_line_info checked by the loader */ +struct bpf_line_info_min { + __u32 insn_off; + __u32 file_name_off; + __u32 line_off; + __u32 line_col; +}; + static inline __u64 ptr_to_u64(const void *ptr) { return (__u64) (unsigned long) ptr; @@ -486,12 +504,22 @@ exit_free: return err; } -static int btf_ext_copy_func_info(struct btf_ext *btf_ext, - __u8 *data, __u32 data_size, - btf_print_fn_t err_log) +struct btf_ext_sec_copy_param { + __u32 off; + __u32 len; + __u32 min_rec_size; + struct btf_ext_info *ext_info; + const char *desc; +}; + +static int btf_ext_copy_info(struct btf_ext *btf_ext, + __u8 *data, __u32 data_size, + struct btf_ext_sec_copy_param *ext_sec, + btf_print_fn_t err_log) { const struct btf_ext_header *hdr = (struct btf_ext_header *)data; - const struct btf_sec_func_info *sinfo; + const struct btf_ext_info_sec *sinfo; + struct btf_ext_info *ext_info; __u32 info_left, record_size; /* The start of the info sec (including the __u32 record_size). */ const void *info; @@ -500,66 +528,69 @@ static int btf_ext_copy_func_info(struct btf_ext *btf_ext, data = data + hdr->hdr_len; data_size -= hdr->hdr_len; - if (hdr->func_info_off & 0x03) { - elog("BTF.ext func_info section is not aligned to 4 bytes\n"); + if (ext_sec->off & 0x03) { + elog(".BTF.ext %s section is not aligned to 4 bytes\n", + ext_sec->desc); return -EINVAL; } - if (data_size < hdr->func_info_off || - hdr->func_info_len > data_size - hdr->func_info_off) { - elog("func_info section (off:%u len:%u) is beyond the end of the ELF section .BTF.ext\n", - hdr->func_info_off, hdr->func_info_len); + if (data_size < ext_sec->off || + ext_sec->len > data_size - ext_sec->off) { + elog("%s section (off:%u len:%u) is beyond the end of the ELF section .BTF.ext\n", + ext_sec->desc, ext_sec->off, ext_sec->len); return -EINVAL; } - info = data + hdr->func_info_off; - info_left = hdr->func_info_len; + info = data + ext_sec->off; + info_left = ext_sec->len; - /* At least a func_info record size */ + /* At least a record size */ if (info_left < sizeof(__u32)) { - elog("BTF.ext func_info record size not found"); + elog(".BTF.ext %s record size not found\n", ext_sec->desc); return -EINVAL; } /* The record size needs to meet the minimum standard */ record_size = *(__u32 *)info; - if (record_size < sizeof(struct bpf_func_info_min) || + if (record_size < ext_sec->min_rec_size || record_size & 0x03) { - elog("BTF.ext func_info invalid record size"); + elog("%s section in .BTF.ext has invalid record size %u\n", + ext_sec->desc, record_size); return -EINVAL; } sinfo = info + sizeof(__u32); info_left -= sizeof(__u32); - /* If no func_info records, return failure now so .BTF.ext - * won't be used. - */ + /* If no records, return failure now so .BTF.ext won't be used. */ if (!info_left) { - elog("BTF.ext no func info records"); + elog("%s section in .BTF.ext has no records", ext_sec->desc); return -EINVAL; } while (info_left) { - unsigned int sec_hdrlen = sizeof(struct btf_sec_func_info); + unsigned int sec_hdrlen = sizeof(struct btf_ext_info_sec); __u64 total_record_size; __u32 num_records; if (info_left < sec_hdrlen) { - elog("BTF.ext func_info header not found"); + elog("%s section header is not found in .BTF.ext\n", + ext_sec->desc); return -EINVAL; } - num_records = sinfo->num_func_info; + num_records = sinfo->num_info; if (num_records == 0) { - elog("incorrect BTF.ext num_func_info"); + elog("%s section has incorrect num_records in .BTF.ext\n", + ext_sec->desc); return -EINVAL; } total_record_size = sec_hdrlen + (__u64)num_records * record_size; if (info_left < total_record_size) { - elog("incorrect BTF.ext num_func_info"); + elog("%s section has incorrect num_records in .BTF.ext\n", + ext_sec->desc); return -EINVAL; } @@ -567,17 +598,49 @@ static int btf_ext_copy_func_info(struct btf_ext *btf_ext, sinfo = (void *)sinfo + total_record_size; } - btf_ext->func_info_len = hdr->func_info_len - sizeof(__u32); - btf_ext->func_info_rec_size = record_size; - btf_ext->func_info = malloc(btf_ext->func_info_len); - if (!btf_ext->func_info) + ext_info = ext_sec->ext_info; + ext_info->len = ext_sec->len - sizeof(__u32); + ext_info->rec_size = record_size; + ext_info->info = malloc(ext_info->len); + if (!ext_info->info) return -ENOMEM; - memcpy(btf_ext->func_info, info + sizeof(__u32), - btf_ext->func_info_len); + memcpy(ext_info->info, info + sizeof(__u32), ext_info->len); return 0; } +static int btf_ext_copy_func_info(struct btf_ext *btf_ext, + __u8 *data, __u32 data_size, + btf_print_fn_t err_log) +{ + const struct btf_ext_header *hdr = (struct btf_ext_header *)data; + struct btf_ext_sec_copy_param param = { + .off = hdr->func_info_off, + .len = hdr->func_info_len, + .min_rec_size = sizeof(struct bpf_func_info_min), + .ext_info = &btf_ext->func_info, + .desc = "func_info" + }; + + return btf_ext_copy_info(btf_ext, data, data_size, ¶m, err_log); +} + +static int btf_ext_copy_line_info(struct btf_ext *btf_ext, + __u8 *data, __u32 data_size, + btf_print_fn_t err_log) +{ + const struct btf_ext_header *hdr = (struct btf_ext_header *)data; + struct btf_ext_sec_copy_param param = { + .off = hdr->line_info_off, + .len = hdr->line_info_len, + .min_rec_size = sizeof(struct bpf_line_info_min), + .ext_info = &btf_ext->line_info, + .desc = "line_info", + }; + + return btf_ext_copy_info(btf_ext, data, data_size, ¶m, err_log); +} + static int btf_ext_parse_hdr(__u8 *data, __u32 data_size, btf_print_fn_t err_log) { @@ -617,7 +680,8 @@ void btf_ext__free(struct btf_ext *btf_ext) if (!btf_ext) return; - free(btf_ext->func_info); + free(btf_ext->func_info.info); + free(btf_ext->line_info.info); free(btf_ext); } @@ -640,25 +704,32 @@ struct btf_ext *btf_ext__new(__u8 *data, __u32 size, btf_print_fn_t err_log) return ERR_PTR(err); } + err = btf_ext_copy_line_info(btf_ext, data, size, err_log); + if (err) { + btf_ext__free(btf_ext); + return ERR_PTR(err); + } + return btf_ext; } -int btf_ext__reloc_func_info(struct btf *btf, struct btf_ext *btf_ext, - const char *sec_name, __u32 insns_cnt, - void **func_info, __u32 *cnt) +static int btf_ext_reloc_info(const struct btf *btf, + const struct btf_ext_info *ext_info, + const char *sec_name, __u32 insns_cnt, + void **info, __u32 *cnt) { - __u32 sec_hdrlen = sizeof(struct btf_sec_func_info); - __u32 i, record_size, existing_flen, records_len; - struct btf_sec_func_info *sinfo; + __u32 sec_hdrlen = sizeof(struct btf_ext_info_sec); + __u32 i, record_size, existing_len, records_len; + struct btf_ext_info_sec *sinfo; const char *info_sec_name; __u64 remain_len; void *data; - record_size = btf_ext->func_info_rec_size; - sinfo = btf_ext->func_info; - remain_len = btf_ext->func_info_len; + record_size = ext_info->rec_size; + sinfo = ext_info->info; + remain_len = ext_info->len; while (remain_len > 0) { - records_len = sinfo->num_func_info * record_size; + records_len = sinfo->num_info * record_size; info_sec_name = btf__name_by_offset(btf, sinfo->sec_name_off); if (strcmp(info_sec_name, sec_name)) { remain_len -= sec_hdrlen + records_len; @@ -666,32 +737,52 @@ int btf_ext__reloc_func_info(struct btf *btf, struct btf_ext *btf_ext, continue; } - existing_flen = (*cnt) * record_size; - data = realloc(*func_info, existing_flen + records_len); + existing_len = (*cnt) * record_size; + data = realloc(*info, existing_len + records_len); if (!data) return -ENOMEM; - memcpy(data + existing_flen, sinfo->data, records_len); + memcpy(data + existing_len, sinfo->data, records_len); /* adjust insn_off only, the rest data will be passed * to the kernel. */ - for (i = 0; i < sinfo->num_func_info; i++) { - struct bpf_func_info_min *record; + for (i = 0; i < sinfo->num_info; i++) { + __u32 *insn_off; - record = data + existing_flen + i * record_size; - record->insn_off = - record->insn_off / sizeof(struct bpf_insn) + + insn_off = data + existing_len + (i * record_size); + *insn_off = *insn_off / sizeof(struct bpf_insn) + insns_cnt; } - *func_info = data; - *cnt += sinfo->num_func_info; + *info = data; + *cnt += sinfo->num_info; return 0; } return -ENOENT; } +int btf_ext__reloc_func_info(const struct btf *btf, const struct btf_ext *btf_ext, + const char *sec_name, __u32 insns_cnt, + void **func_info, __u32 *cnt) +{ + return btf_ext_reloc_info(btf, &btf_ext->func_info, sec_name, + insns_cnt, func_info, cnt); +} + +int btf_ext__reloc_line_info(const struct btf *btf, const struct btf_ext *btf_ext, + const char *sec_name, __u32 insns_cnt, + void **line_info, __u32 *cnt) +{ + return btf_ext_reloc_info(btf, &btf_ext->line_info, sec_name, + insns_cnt, line_info, cnt); +} + __u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext) { - return btf_ext->func_info_rec_size; + return btf_ext->func_info.rec_size; +} + +__u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext) +{ + return btf_ext->line_info.rec_size; } diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index 936177a538cd..b0610dcdae6b 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -51,6 +51,8 @@ struct btf_ext_header { /* All offsets are in bytes relative to the end of this header */ __u32 func_info_off; __u32 func_info_len; + __u32 line_info_off; + __u32 line_info_len; }; typedef int (*btf_print_fn_t)(const char *, ...) @@ -70,10 +72,16 @@ LIBBPF_API int btf__get_from_id(__u32 id, struct btf **btf); struct btf_ext *btf_ext__new(__u8 *data, __u32 size, btf_print_fn_t err_log); void btf_ext__free(struct btf_ext *btf_ext); -int btf_ext__reloc_func_info(struct btf *btf, struct btf_ext *btf_ext, +int btf_ext__reloc_func_info(const struct btf *btf, + const struct btf_ext *btf_ext, const char *sec_name, __u32 insns_cnt, void **func_info, __u32 *func_info_len); +int btf_ext__reloc_line_info(const struct btf *btf, + const struct btf_ext *btf_ext, + const char *sec_name, __u32 insns_cnt, + void **line_info, __u32 *cnt); __u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext); +__u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext); #ifdef __cplusplus } /* extern "C" */ diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 4ea3368bf803..e2bc75ee1614 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -170,6 +170,10 @@ struct bpf_program { __u32 func_info_cnt; struct bpf_capabilities *caps; + + void *line_info; + __u32 line_info_rec_size; + __u32 line_info_cnt; }; struct bpf_map { @@ -1342,6 +1346,19 @@ bpf_program_reloc_btf_ext(struct bpf_program *prog, struct bpf_object *obj, prog->func_info_rec_size = btf_ext__func_info_rec_size(obj->btf_ext); } + if (!insn_offset || prog->line_info) { + err = btf_ext__reloc_line_info(obj->btf, obj->btf_ext, + section_name, insn_offset, + &prog->line_info, + &prog->line_info_cnt); + if (err) + return check_btf_ext_reloc_err(prog, err, + prog->line_info, + "bpf_line_info"); + + prog->line_info_rec_size = btf_ext__line_info_rec_size(obj->btf_ext); + } + if (!insn_offset) prog->btf_fd = btf__fd(obj->btf); @@ -1526,6 +1543,9 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, load_attr.func_info = prog->func_info; load_attr.func_info_rec_size = prog->func_info_rec_size; load_attr.func_info_cnt = prog->func_info_cnt; + load_attr.line_info = prog->line_info; + load_attr.line_info_rec_size = prog->line_info_rec_size; + load_attr.line_info_cnt = prog->line_info_cnt; if (!load_attr.insns || !load_attr.insns_cnt) return -EINVAL; -- cgit v1.2.3-59-g8ed1b