| Message ID | 20190312053051.2690567-3-songliubraving@fb.com |
|---|---|
| State | Awaiting Upstream |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | perf annotation of BPF programs | expand |
Em Mon, Mar 11, 2019 at 10:30:38PM -0700, Song Liu escreveu: > Currently, bpf_prog_info includes 9 arrays. The user has the option to > fetch any combination of these arrays. However, this requires a lot of > handling of these arrays. This work becomes more tricky when we need to > store bpf_prog_info to a file, because these arrays are allocated > independently. > > This patch introduces struct bpf_prog_info_linear, which stores arrays > of bpf_prog_info in continues memory. Helper functions are introduced > to unify the work to get different information of bpf_prog_info. > Specifically, bpf_program__get_prog_info_linear() allows the user to > select which arrays to fetch, and handles details for the user. > > Plesae see the comments before enum bpf_prog_info_array for more details > and examples. > > Cc: Daniel Borkmann <daniel@iogearbox.net> > Cc: Alexei Starovoitov <ast@kernel.org> > Signed-off-by: Song Liu <songliubraving@fb.com> > --- > tools/lib/bpf/libbpf.c | 251 +++++++++++++++++++++++++++++++++++++++ > tools/lib/bpf/libbpf.h | 63 ++++++++++ > tools/lib/bpf/libbpf.map | 3 + > 3 files changed, 317 insertions(+) > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > index d5b830d60601..98ec9a8cd7af 100644 > --- a/tools/lib/bpf/libbpf.c > +++ b/tools/lib/bpf/libbpf.c > @@ -112,6 +112,11 @@ void libbpf_print(enum libbpf_print_level level, const char *format, ...) > # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ > #endif > > +static inline __u64 ptr_to_u64(const void *ptr) > +{ > + return (__u64) (unsigned long) ptr; > +} > + > struct bpf_capabilities { > /* v4.14: kernel support for program & map names. */ > __u32 name:1; > @@ -2999,3 +3004,249 @@ bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size, > ring_buffer_write_tail(header, data_tail); > return ret; > } > + > +struct bpf_prog_info_array_desc { > + int array_offset; /* e.g. offset of jited_prog_insns */ > + int count_offset; /* e.g. offset of jited_prog_len */ > + int size_offset; /* > 0: offset of rec size, > + * < 0: fix size of -size_offset > + */ > +}; > + > +static struct bpf_prog_info_array_desc bpf_prog_info_array_desc[] = { > + [BPF_PROG_INFO_JITED_INSNS] = { > + offsetof(struct bpf_prog_info, jited_prog_insns), > + offsetof(struct bpf_prog_info, jited_prog_len), > + -1, > + }, > + [BPF_PROG_INFO_XLATED_INSNS] = { > + offsetof(struct bpf_prog_info, xlated_prog_insns), > + offsetof(struct bpf_prog_info, xlated_prog_len), > + -1, > + }, Can be done on top, but this is too much boilerplate, later we can use something like: @define BPF_PROG_INFO_ENTRY(idx, array, count, offset) \ [BPF_PROG_INFO ## index_name] = { \ offsetof(struct bpf_prog_info, array), \ offsetof(struct bpf_prog_info, count), \ (int)offset \ } And then have a more compact static struct bpf_prog_info_array_desc bpf_prog_info_array_desc[] = { BPF_PROG_INFO_ENTRY(JITED_INSNS, jited_prog_insns, jided_prog_len, -1 ); BPF_PROG_INFO_ENTRY(MAP_IDS, map_ids, nr_map_ids, -sizeof(__u32)); etc. Anyway, processing it as-is for now. > + [BPF_PROG_INFO_MAP_IDS] = { > + offsetof(struct bpf_prog_info, map_ids), > + offsetof(struct bpf_prog_info, nr_map_ids), > + -(int)sizeof(__u32), > + }, > + [BPF_PROG_INFO_JITED_KSYMS] = { > + offsetof(struct bpf_prog_info, jited_ksyms), > + offsetof(struct bpf_prog_info, nr_jited_ksyms), > + -(int)sizeof(__u64), > + }, > + [BPF_PROG_INFO_JITED_FUNC_LENS] = { > + offsetof(struct bpf_prog_info, jited_func_lens), > + offsetof(struct bpf_prog_info, nr_jited_func_lens), > + -(int)sizeof(__u32), > + }, > + [BPF_PROG_INFO_FUNC_INFO] = { > + offsetof(struct bpf_prog_info, func_info), > + offsetof(struct bpf_prog_info, nr_func_info), > + offsetof(struct bpf_prog_info, func_info_rec_size), > + }, > + [BPF_PROG_INFO_LINE_INFO] = { > + offsetof(struct bpf_prog_info, line_info), > + offsetof(struct bpf_prog_info, nr_line_info), > + offsetof(struct bpf_prog_info, line_info_rec_size), > + }, > + [BPF_PROG_INFO_JITED_LINE_INFO] = { > + offsetof(struct bpf_prog_info, jited_line_info), > + offsetof(struct bpf_prog_info, nr_jited_line_info), > + offsetof(struct bpf_prog_info, jited_line_info_rec_size), > + }, > + [BPF_PROG_INFO_PROG_TAGS] = { > + offsetof(struct bpf_prog_info, prog_tags), > + offsetof(struct bpf_prog_info, nr_prog_tags), > + -(int)sizeof(__u8) * BPF_TAG_SIZE, > + }, > + > +}; > + > +static __u32 bpf_prog_info_read_offset_u32(struct bpf_prog_info *info, int offset) > +{ > + __u32 *array = (__u32 *)info; > + > + if (offset >= 0) > + return array[offset / sizeof(__u32)]; > + return -(int)offset; > +} > + > +static __u64 bpf_prog_info_read_offset_u64(struct bpf_prog_info *info, int offset) > +{ > + __u64 *array = (__u64 *)info; > + > + if (offset >= 0) > + return array[offset / sizeof(__u64)]; > + return -(int)offset; > +} > + > +static void bpf_prog_info_set_offset_u32(struct bpf_prog_info *info, int offset, > + __u32 val) > +{ > + __u32 *array = (__u32 *)info; > + > + if (offset >= 0) > + array[offset / sizeof(__u32)] = val; > +} > + > +static void bpf_prog_info_set_offset_u64(struct bpf_prog_info *info, int offset, > + __u64 val) > +{ > + __u64 *array = (__u64 *)info; > + > + if (offset >= 0) > + array[offset / sizeof(__u64)] = val; > +} > + > +struct bpf_prog_info_linear * > +bpf_program__get_prog_info_linear(int fd, __u64 arrays) > +{ > + struct bpf_prog_info_linear *info_linear; > + struct bpf_prog_info info = {}; > + __u32 info_len = sizeof(info); > + __u32 data_len = 0; > + int i, err; > + void *ptr; > + > + if (arrays >> BPF_PROG_INFO_LAST_ARRAY) > + return ERR_PTR(-EINVAL); > + > + /* step 1: get array dimensions */ > + err = bpf_obj_get_info_by_fd(fd, &info, &info_len); > + if (err) { > + pr_debug("can't get prog info: %s", strerror(errno)); > + return ERR_PTR(-EFAULT); > + } > + > + /* step 2: calculate total size of all arrays */ > + for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) { > + bool include_array = (arrays & (1UL << i)) > 0; > + struct bpf_prog_info_array_desc *desc; > + __u32 count, size; > + > + desc = bpf_prog_info_array_desc + i; > + > + /* kernel is too old to support this field */ > + if (info_len < desc->array_offset + sizeof(__u32) || > + info_len < desc->count_offset + sizeof(__u32) || > + (desc->size_offset > 0 && info_len < desc->size_offset)) > + include_array = false; > + > + if (!include_array) { > + arrays &= ~(1UL << i); /* clear the bit */ > + continue; > + } > + > + count = bpf_prog_info_read_offset_u32(&info, desc->count_offset); > + size = bpf_prog_info_read_offset_u32(&info, desc->size_offset); > + > + data_len += count * size; > + } > + > + /* step 3: allocate continuous memory */ > + data_len = roundup(data_len, sizeof(__u64)); > + info_linear = malloc(sizeof(struct bpf_prog_info_linear) + data_len); > + if (!info_linear) > + return ERR_PTR(-ENOMEM); > + > + /* step 4: fill data to info_linear->info */ > + info_linear->arrays = arrays; > + memset(&info_linear->info, 0, sizeof(info)); > + ptr = info_linear->data; > + > + for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) { > + struct bpf_prog_info_array_desc *desc; > + __u32 count, size; > + > + if ((arrays & (1UL << i)) == 0) > + continue; > + > + desc = bpf_prog_info_array_desc + i; > + count = bpf_prog_info_read_offset_u32(&info, desc->count_offset); > + size = bpf_prog_info_read_offset_u32(&info, desc->size_offset); > + bpf_prog_info_set_offset_u32(&info_linear->info, > + desc->count_offset, count); > + bpf_prog_info_set_offset_u32(&info_linear->info, > + desc->size_offset, size); > + bpf_prog_info_set_offset_u64(&info_linear->info, > + desc->array_offset, > + ptr_to_u64(ptr)); > + ptr += count * size; > + } > + > + /* step 5: call syscall again to get required arrays */ > + err = bpf_obj_get_info_by_fd(fd, &info_linear->info, &info_len); > + if (err) { > + pr_debug("can't get prog info: %s", strerror(errno)); > + free(info_linear); > + return ERR_PTR(-EFAULT); > + } > + > + /* step 6: verify the data */ > + for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) { > + struct bpf_prog_info_array_desc *desc; > + __u32 v1, v2; > + > + if ((arrays & (1UL << i)) == 0) > + continue; > + > + desc = bpf_prog_info_array_desc + i; > + v1 = bpf_prog_info_read_offset_u32(&info, desc->count_offset); > + v2 = bpf_prog_info_read_offset_u32(&info_linear->info, > + desc->count_offset); > + if (v1 != v2) > + pr_warning("%s: mismatch in element count\n", __func__); > + > + v1 = bpf_prog_info_read_offset_u32(&info, desc->size_offset); > + v2 = bpf_prog_info_read_offset_u32(&info_linear->info, > + desc->size_offset); > + if (v1 != v2) > + pr_warning("%s: mismatch in rec size\n", __func__); > + } > + > + /* step 7: update info_len and data_len */ > + info_linear->info_len = sizeof(struct bpf_prog_info); > + info_linear->data_len = data_len; > + > + return info_linear; > +} > + > +void bpf_program__bpil_addr_to_offs(struct bpf_prog_info_linear *info_linear) > +{ > + int i; > + > + for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) { > + struct bpf_prog_info_array_desc *desc; > + __u64 addr, offs; > + > + if ((info_linear->arrays & (1UL << i)) == 0) > + continue; > + > + desc = bpf_prog_info_array_desc + i; > + addr = bpf_prog_info_read_offset_u64(&info_linear->info, > + desc->array_offset); > + offs = addr - ptr_to_u64(info_linear->data); > + bpf_prog_info_set_offset_u64(&info_linear->info, > + desc->array_offset, offs); > + } > +} > + > +void bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear) > +{ > + int i; > + > + for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) { > + struct bpf_prog_info_array_desc *desc; > + __u64 addr, offs; > + > + if ((info_linear->arrays & (1UL << i)) == 0) > + continue; > + > + desc = bpf_prog_info_array_desc + i; > + offs = bpf_prog_info_read_offset_u64(&info_linear->info, > + desc->array_offset); > + addr = offs + ptr_to_u64(info_linear->data); > + bpf_prog_info_set_offset_u64(&info_linear->info, > + desc->array_offset, addr); > + } > +} > diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h > index b4652aa1a58a..c7645a5e1ac0 100644 > --- a/tools/lib/bpf/libbpf.h > +++ b/tools/lib/bpf/libbpf.h > @@ -377,6 +377,69 @@ LIBBPF_API bool bpf_probe_map_type(enum bpf_map_type map_type, __u32 ifindex); > LIBBPF_API bool bpf_probe_helper(enum bpf_func_id id, > enum bpf_prog_type prog_type, __u32 ifindex); > > +/* > + * Get bpf_prog_info in continuous memory > + * > + * struct bpf_prog_info has multiple arrays. The user has option to choose > + * arrays to fetch from kernel. The following APIs provide uniform way to > + * fetch these data. All arrays in bpf_prog_info are stored in singile > + * continuous memory region. This makes it easy to store the info in a > + * file. > + * > + * Before writing bpf_prog_info_linear to files, it is necessary to > + * translate pointers bpf_prog_info to offsets. Helper functions > + * bpf_program__bpil_addr_to_offs() and bpf_program__bpil_offs_to_addr() > + * are introduced to switch between pointers and offsets. > + * > + * Examples: > + * # To fetch map_ids and prog_tags: > + * __u64 arrays = (1UL << BPF_PROG_INFO_MAP_IDS) | > + * (1UL << BPF_PROG_INFO_PROG_TAGS); > + * struct bpf_prog_info_linear *info_linear = > + * bpf_program__get_prog_info_linear(fd, arrays); > + * > + * # To save data in file > + * bpf_program__bpil_addr_to_offs(info_linear); > + * write(f, info_linear, sizeof(*info_linear) + info_linear->data_len); > + * > + * # To read data from file > + * read(f, info_linear, <proper_size>); > + * bpf_program__bpil_offs_to_addr(info_linear); > + */ > +enum bpf_prog_info_array { > + BPF_PROG_INFO_FIRST_ARRAY = 0, > + BPF_PROG_INFO_JITED_INSNS = 0, > + BPF_PROG_INFO_XLATED_INSNS, > + BPF_PROG_INFO_MAP_IDS, > + BPF_PROG_INFO_JITED_KSYMS, > + BPF_PROG_INFO_JITED_FUNC_LENS, > + BPF_PROG_INFO_FUNC_INFO, > + BPF_PROG_INFO_LINE_INFO, > + BPF_PROG_INFO_JITED_LINE_INFO, > + BPF_PROG_INFO_PROG_TAGS, > + BPF_PROG_INFO_LAST_ARRAY, > +}; > + > +struct bpf_prog_info_linear { > + /* size of struct bpf_prog_info, when the tool is compiled */ > + __u32 info_len; > + /* total bytes allocated for data, round up to 8 bytes */ > + __u32 data_len; > + /* which arrays are included in data */ > + __u64 arrays; > + struct bpf_prog_info info; > + __u8 data[]; > +}; > + > +LIBBPF_API struct bpf_prog_info_linear * > +bpf_program__get_prog_info_linear(int fd, __u64 arrays); > + > +LIBBPF_API void > +bpf_program__bpil_addr_to_offs(struct bpf_prog_info_linear *info_linear); > + > +LIBBPF_API void > +bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear); > + > #ifdef __cplusplus > } /* extern "C" */ > #endif > diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map > index 778a26702a70..f3ce50500cf2 100644 > --- a/tools/lib/bpf/libbpf.map > +++ b/tools/lib/bpf/libbpf.map > @@ -153,4 +153,7 @@ LIBBPF_0.0.2 { > xsk_socket__delete; > xsk_umem__fd; > xsk_socket__fd; > + bpf_program__get_prog_info_linear; > + bpf_program__bpil_addr_to_offs; > + bpf_program__bpil_offs_to_addr; > } LIBBPF_0.0.1; > -- > 2.17.1
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index d5b830d60601..98ec9a8cd7af 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -112,6 +112,11 @@ void libbpf_print(enum libbpf_print_level level, const char *format, ...) # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ #endif +static inline __u64 ptr_to_u64(const void *ptr) +{ + return (__u64) (unsigned long) ptr; +} + struct bpf_capabilities { /* v4.14: kernel support for program & map names. */ __u32 name:1; @@ -2999,3 +3004,249 @@ bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size, ring_buffer_write_tail(header, data_tail); return ret; } + +struct bpf_prog_info_array_desc { + int array_offset; /* e.g. offset of jited_prog_insns */ + int count_offset; /* e.g. offset of jited_prog_len */ + int size_offset; /* > 0: offset of rec size, + * < 0: fix size of -size_offset + */ +}; + +static struct bpf_prog_info_array_desc bpf_prog_info_array_desc[] = { + [BPF_PROG_INFO_JITED_INSNS] = { + offsetof(struct bpf_prog_info, jited_prog_insns), + offsetof(struct bpf_prog_info, jited_prog_len), + -1, + }, + [BPF_PROG_INFO_XLATED_INSNS] = { + offsetof(struct bpf_prog_info, xlated_prog_insns), + offsetof(struct bpf_prog_info, xlated_prog_len), + -1, + }, + [BPF_PROG_INFO_MAP_IDS] = { + offsetof(struct bpf_prog_info, map_ids), + offsetof(struct bpf_prog_info, nr_map_ids), + -(int)sizeof(__u32), + }, + [BPF_PROG_INFO_JITED_KSYMS] = { + offsetof(struct bpf_prog_info, jited_ksyms), + offsetof(struct bpf_prog_info, nr_jited_ksyms), + -(int)sizeof(__u64), + }, + [BPF_PROG_INFO_JITED_FUNC_LENS] = { + offsetof(struct bpf_prog_info, jited_func_lens), + offsetof(struct bpf_prog_info, nr_jited_func_lens), + -(int)sizeof(__u32), + }, + [BPF_PROG_INFO_FUNC_INFO] = { + offsetof(struct bpf_prog_info, func_info), + offsetof(struct bpf_prog_info, nr_func_info), + offsetof(struct bpf_prog_info, func_info_rec_size), + }, + [BPF_PROG_INFO_LINE_INFO] = { + offsetof(struct bpf_prog_info, line_info), + offsetof(struct bpf_prog_info, nr_line_info), + offsetof(struct bpf_prog_info, line_info_rec_size), + }, + [BPF_PROG_INFO_JITED_LINE_INFO] = { + offsetof(struct bpf_prog_info, jited_line_info), + offsetof(struct bpf_prog_info, nr_jited_line_info), + offsetof(struct bpf_prog_info, jited_line_info_rec_size), + }, + [BPF_PROG_INFO_PROG_TAGS] = { + offsetof(struct bpf_prog_info, prog_tags), + offsetof(struct bpf_prog_info, nr_prog_tags), + -(int)sizeof(__u8) * BPF_TAG_SIZE, + }, + +}; + +static __u32 bpf_prog_info_read_offset_u32(struct bpf_prog_info *info, int offset) +{ + __u32 *array = (__u32 *)info; + + if (offset >= 0) + return array[offset / sizeof(__u32)]; + return -(int)offset; +} + +static __u64 bpf_prog_info_read_offset_u64(struct bpf_prog_info *info, int offset) +{ + __u64 *array = (__u64 *)info; + + if (offset >= 0) + return array[offset / sizeof(__u64)]; + return -(int)offset; +} + +static void bpf_prog_info_set_offset_u32(struct bpf_prog_info *info, int offset, + __u32 val) +{ + __u32 *array = (__u32 *)info; + + if (offset >= 0) + array[offset / sizeof(__u32)] = val; +} + +static void bpf_prog_info_set_offset_u64(struct bpf_prog_info *info, int offset, + __u64 val) +{ + __u64 *array = (__u64 *)info; + + if (offset >= 0) + array[offset / sizeof(__u64)] = val; +} + +struct bpf_prog_info_linear * +bpf_program__get_prog_info_linear(int fd, __u64 arrays) +{ + struct bpf_prog_info_linear *info_linear; + struct bpf_prog_info info = {}; + __u32 info_len = sizeof(info); + __u32 data_len = 0; + int i, err; + void *ptr; + + if (arrays >> BPF_PROG_INFO_LAST_ARRAY) + return ERR_PTR(-EINVAL); + + /* step 1: get array dimensions */ + err = bpf_obj_get_info_by_fd(fd, &info, &info_len); + if (err) { + pr_debug("can't get prog info: %s", strerror(errno)); + return ERR_PTR(-EFAULT); + } + + /* step 2: calculate total size of all arrays */ + for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) { + bool include_array = (arrays & (1UL << i)) > 0; + struct bpf_prog_info_array_desc *desc; + __u32 count, size; + + desc = bpf_prog_info_array_desc + i; + + /* kernel is too old to support this field */ + if (info_len < desc->array_offset + sizeof(__u32) || + info_len < desc->count_offset + sizeof(__u32) || + (desc->size_offset > 0 && info_len < desc->size_offset)) + include_array = false; + + if (!include_array) { + arrays &= ~(1UL << i); /* clear the bit */ + continue; + } + + count = bpf_prog_info_read_offset_u32(&info, desc->count_offset); + size = bpf_prog_info_read_offset_u32(&info, desc->size_offset); + + data_len += count * size; + } + + /* step 3: allocate continuous memory */ + data_len = roundup(data_len, sizeof(__u64)); + info_linear = malloc(sizeof(struct bpf_prog_info_linear) + data_len); + if (!info_linear) + return ERR_PTR(-ENOMEM); + + /* step 4: fill data to info_linear->info */ + info_linear->arrays = arrays; + memset(&info_linear->info, 0, sizeof(info)); + ptr = info_linear->data; + + for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) { + struct bpf_prog_info_array_desc *desc; + __u32 count, size; + + if ((arrays & (1UL << i)) == 0) + continue; + + desc = bpf_prog_info_array_desc + i; + count = bpf_prog_info_read_offset_u32(&info, desc->count_offset); + size = bpf_prog_info_read_offset_u32(&info, desc->size_offset); + bpf_prog_info_set_offset_u32(&info_linear->info, + desc->count_offset, count); + bpf_prog_info_set_offset_u32(&info_linear->info, + desc->size_offset, size); + bpf_prog_info_set_offset_u64(&info_linear->info, + desc->array_offset, + ptr_to_u64(ptr)); + ptr += count * size; + } + + /* step 5: call syscall again to get required arrays */ + err = bpf_obj_get_info_by_fd(fd, &info_linear->info, &info_len); + if (err) { + pr_debug("can't get prog info: %s", strerror(errno)); + free(info_linear); + return ERR_PTR(-EFAULT); + } + + /* step 6: verify the data */ + for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) { + struct bpf_prog_info_array_desc *desc; + __u32 v1, v2; + + if ((arrays & (1UL << i)) == 0) + continue; + + desc = bpf_prog_info_array_desc + i; + v1 = bpf_prog_info_read_offset_u32(&info, desc->count_offset); + v2 = bpf_prog_info_read_offset_u32(&info_linear->info, + desc->count_offset); + if (v1 != v2) + pr_warning("%s: mismatch in element count\n", __func__); + + v1 = bpf_prog_info_read_offset_u32(&info, desc->size_offset); + v2 = bpf_prog_info_read_offset_u32(&info_linear->info, + desc->size_offset); + if (v1 != v2) + pr_warning("%s: mismatch in rec size\n", __func__); + } + + /* step 7: update info_len and data_len */ + info_linear->info_len = sizeof(struct bpf_prog_info); + info_linear->data_len = data_len; + + return info_linear; +} + +void bpf_program__bpil_addr_to_offs(struct bpf_prog_info_linear *info_linear) +{ + int i; + + for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) { + struct bpf_prog_info_array_desc *desc; + __u64 addr, offs; + + if ((info_linear->arrays & (1UL << i)) == 0) + continue; + + desc = bpf_prog_info_array_desc + i; + addr = bpf_prog_info_read_offset_u64(&info_linear->info, + desc->array_offset); + offs = addr - ptr_to_u64(info_linear->data); + bpf_prog_info_set_offset_u64(&info_linear->info, + desc->array_offset, offs); + } +} + +void bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear) +{ + int i; + + for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) { + struct bpf_prog_info_array_desc *desc; + __u64 addr, offs; + + if ((info_linear->arrays & (1UL << i)) == 0) + continue; + + desc = bpf_prog_info_array_desc + i; + offs = bpf_prog_info_read_offset_u64(&info_linear->info, + desc->array_offset); + addr = offs + ptr_to_u64(info_linear->data); + bpf_prog_info_set_offset_u64(&info_linear->info, + desc->array_offset, addr); + } +} diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index b4652aa1a58a..c7645a5e1ac0 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -377,6 +377,69 @@ LIBBPF_API bool bpf_probe_map_type(enum bpf_map_type map_type, __u32 ifindex); LIBBPF_API bool bpf_probe_helper(enum bpf_func_id id, enum bpf_prog_type prog_type, __u32 ifindex); +/* + * Get bpf_prog_info in continuous memory + * + * struct bpf_prog_info has multiple arrays. The user has option to choose + * arrays to fetch from kernel. The following APIs provide uniform way to + * fetch these data. All arrays in bpf_prog_info are stored in singile + * continuous memory region. This makes it easy to store the info in a + * file. + * + * Before writing bpf_prog_info_linear to files, it is necessary to + * translate pointers bpf_prog_info to offsets. Helper functions + * bpf_program__bpil_addr_to_offs() and bpf_program__bpil_offs_to_addr() + * are introduced to switch between pointers and offsets. + * + * Examples: + * # To fetch map_ids and prog_tags: + * __u64 arrays = (1UL << BPF_PROG_INFO_MAP_IDS) | + * (1UL << BPF_PROG_INFO_PROG_TAGS); + * struct bpf_prog_info_linear *info_linear = + * bpf_program__get_prog_info_linear(fd, arrays); + * + * # To save data in file + * bpf_program__bpil_addr_to_offs(info_linear); + * write(f, info_linear, sizeof(*info_linear) + info_linear->data_len); + * + * # To read data from file + * read(f, info_linear, <proper_size>); + * bpf_program__bpil_offs_to_addr(info_linear); + */ +enum bpf_prog_info_array { + BPF_PROG_INFO_FIRST_ARRAY = 0, + BPF_PROG_INFO_JITED_INSNS = 0, + BPF_PROG_INFO_XLATED_INSNS, + BPF_PROG_INFO_MAP_IDS, + BPF_PROG_INFO_JITED_KSYMS, + BPF_PROG_INFO_JITED_FUNC_LENS, + BPF_PROG_INFO_FUNC_INFO, + BPF_PROG_INFO_LINE_INFO, + BPF_PROG_INFO_JITED_LINE_INFO, + BPF_PROG_INFO_PROG_TAGS, + BPF_PROG_INFO_LAST_ARRAY, +}; + +struct bpf_prog_info_linear { + /* size of struct bpf_prog_info, when the tool is compiled */ + __u32 info_len; + /* total bytes allocated for data, round up to 8 bytes */ + __u32 data_len; + /* which arrays are included in data */ + __u64 arrays; + struct bpf_prog_info info; + __u8 data[]; +}; + +LIBBPF_API struct bpf_prog_info_linear * +bpf_program__get_prog_info_linear(int fd, __u64 arrays); + +LIBBPF_API void +bpf_program__bpil_addr_to_offs(struct bpf_prog_info_linear *info_linear); + +LIBBPF_API void +bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear); + #ifdef __cplusplus } /* extern "C" */ #endif diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 778a26702a70..f3ce50500cf2 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -153,4 +153,7 @@ LIBBPF_0.0.2 { xsk_socket__delete; xsk_umem__fd; xsk_socket__fd; + bpf_program__get_prog_info_linear; + bpf_program__bpil_addr_to_offs; + bpf_program__bpil_offs_to_addr; } LIBBPF_0.0.1;
Currently, bpf_prog_info includes 9 arrays. The user has the option to fetch any combination of these arrays. However, this requires a lot of handling of these arrays. This work becomes more tricky when we need to store bpf_prog_info to a file, because these arrays are allocated independently. This patch introduces struct bpf_prog_info_linear, which stores arrays of bpf_prog_info in continues memory. Helper functions are introduced to unify the work to get different information of bpf_prog_info. Specifically, bpf_program__get_prog_info_linear() allows the user to select which arrays to fetch, and handles details for the user. Plesae see the comments before enum bpf_prog_info_array for more details and examples. Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Song Liu <songliubraving@fb.com> --- tools/lib/bpf/libbpf.c | 251 +++++++++++++++++++++++++++++++++++++++ tools/lib/bpf/libbpf.h | 63 ++++++++++ tools/lib/bpf/libbpf.map | 3 + 3 files changed, 317 insertions(+)