diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index bfef3d606b54e..c8861c9e3635f 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -389,7 +389,7 @@ void btf__free(struct btf *btf) if (!btf) return; - if (btf->fd != -1) + if (btf->fd >= 0) close(btf->fd); free(btf->data); @@ -700,6 +700,11 @@ int btf__fd(const struct btf *btf) return btf->fd; } +void btf__set_fd(struct btf *btf, int fd) +{ + btf->fd = fd; +} + const void *btf__get_raw_data(const struct btf *btf, __u32 *size) { *size = btf->data_size; diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index 06cd1731c1547..173eff23c4721 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -79,6 +79,7 @@ LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id); LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id); LIBBPF_API int btf__align_of(const struct btf *btf, __u32 id); LIBBPF_API int btf__fd(const struct btf *btf); +LIBBPF_API void btf__set_fd(struct btf *btf, int fd); LIBBPF_API const void *btf__get_raw_data(const struct btf *btf, __u32 *size); LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset); LIBBPF_API int btf__get_from_id(__u32 id, struct btf **btf); diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 88a483627a2b9..6602eb479596b 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2338,18 +2338,23 @@ static bool section_have_execinstr(struct bpf_object *obj, int idx) return false; } -static void bpf_object__sanitize_btf(struct bpf_object *obj) +static bool btf_needs_sanitization(struct bpf_object *obj) +{ + bool has_func_global = obj->caps.btf_func_global; + bool has_datasec = obj->caps.btf_datasec; + bool has_func = obj->caps.btf_func; + + return !has_func || !has_datasec || !has_func_global; +} + +static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf) { bool has_func_global = obj->caps.btf_func_global; bool has_datasec = obj->caps.btf_datasec; bool has_func = obj->caps.btf_func; - struct btf *btf = obj->btf; struct btf_type *t; int i, j, vlen; - if (!obj->btf || (has_func && has_datasec && has_func_global)) - return; - for (i = 1; i <= btf__get_nr_types(btf); i++) { t = (struct btf_type *)btf__type_by_id(btf, i); @@ -2402,17 +2407,6 @@ static void bpf_object__sanitize_btf(struct bpf_object *obj) } } -static void bpf_object__sanitize_btf_ext(struct bpf_object *obj) -{ - if (!obj->btf_ext) - return; - - if (!obj->caps.btf_func) { - btf_ext__free(obj->btf_ext); - obj->btf_ext = NULL; - } -} - static bool libbpf_needs_btf(const struct bpf_object *obj) { return obj->efile.btf_maps_shndx >= 0 || @@ -2473,19 +2467,11 @@ static int bpf_object__finalize_btf(struct bpf_object *obj) return 0; err = btf__finalize_data(obj, obj->btf); - if (!err) - return 0; - - pr_warn("Error finalizing %s: %d.\n", BTF_ELF_SEC, err); - btf__free(obj->btf); - obj->btf = NULL; - btf_ext__free(obj->btf_ext); - obj->btf_ext = NULL; - - if (libbpf_needs_btf(obj)) { - pr_warn("BTF is required, but is missing or corrupted.\n"); - return -ENOENT; + if (err) { + pr_warn("Error finalizing %s: %d.\n", BTF_ELF_SEC, err); + return err; } + return 0; } @@ -2538,30 +2524,50 @@ static int bpf_object__load_vmlinux_btf(struct bpf_object *obj) static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj) { + struct btf *kern_btf = obj->btf; + bool btf_mandatory, sanitize; int err = 0; if (!obj->btf) return 0; - bpf_object__sanitize_btf(obj); - bpf_object__sanitize_btf_ext(obj); + sanitize = btf_needs_sanitization(obj); + if (sanitize) { + const void *orig_data; + void *san_data; + __u32 sz; - err = btf__load(obj->btf); - if (err) { - pr_warn("Error loading %s into kernel: %d.\n", - BTF_ELF_SEC, err); - btf__free(obj->btf); - obj->btf = NULL; - /* btf_ext can't exist without btf, so free it as well */ - if (obj->btf_ext) { - btf_ext__free(obj->btf_ext); - obj->btf_ext = NULL; - } + /* clone BTF to sanitize a copy and leave the original intact */ + orig_data = btf__get_raw_data(obj->btf, &sz); + san_data = malloc(sz); + if (!san_data) + return -ENOMEM; + memcpy(san_data, orig_data, sz); + kern_btf = btf__new(san_data, sz); + if (IS_ERR(kern_btf)) + return PTR_ERR(kern_btf); - if (kernel_needs_btf(obj)) - return err; + bpf_object__sanitize_btf(obj, kern_btf); } - return 0; + + err = btf__load(kern_btf); + if (sanitize) { + if (!err) { + /* move fd to libbpf's BTF */ + btf__set_fd(obj->btf, btf__fd(kern_btf)); + btf__set_fd(kern_btf, -1); + } + btf__free(kern_btf); + } + if (err) { + btf_mandatory = kernel_needs_btf(obj); + pr_warn("Error loading .BTF into kernel: %d. %s\n", err, + btf_mandatory ? "BTF is mandatory, can't proceed." + : "BTF is optional, ignoring."); + if (!btf_mandatory) + err = 0; + } + return err; } static int bpf_object__elf_collect(struct bpf_object *obj) @@ -3785,7 +3791,7 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map) create_attr.btf_fd = 0; create_attr.btf_key_type_id = 0; create_attr.btf_value_type_id = 0; - if (obj->btf && !bpf_map_find_btf_info(obj, map)) { + if (obj->btf && btf__fd(obj->btf) >= 0 && !bpf_map_find_btf_info(obj, map)) { 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; @@ -5369,18 +5375,17 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, load_attr.kern_version = kern_version; load_attr.prog_ifindex = prog->prog_ifindex; } - /* if .BTF.ext was loaded, kernel supports associated BTF for prog */ - if (prog->obj->btf_ext) - btf_fd = bpf_object__btf_fd(prog->obj); - else - btf_fd = -1; - load_attr.prog_btf_fd = btf_fd >= 0 ? btf_fd : 0; - 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; + /* specify func_info/line_info only if kernel supports them */ + btf_fd = bpf_object__btf_fd(prog->obj); + if (btf_fd >= 0 && prog->obj->caps.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; + 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; + } load_attr.log_level = prog->log_level; load_attr.prog_flags = prog->prog_flags; @@ -8586,7 +8591,7 @@ static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt, struct perf_buffer_params *p) { const char *online_cpus_file = "/sys/devices/system/cpu/online"; - struct bpf_map_info map = {}; + struct bpf_map_info map; char msg[STRERR_BUFSIZE]; struct perf_buffer *pb; bool *online = NULL; @@ -8599,19 +8604,28 @@ static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt, return ERR_PTR(-EINVAL); } + /* best-effort sanity checks */ + memset(&map, 0, sizeof(map)); map_info_len = sizeof(map); err = bpf_obj_get_info_by_fd(map_fd, &map, &map_info_len); if (err) { err = -errno; - pr_warn("failed to get map info for map FD %d: %s\n", - map_fd, libbpf_strerror_r(err, msg, sizeof(msg))); - return ERR_PTR(err); - } - - if (map.type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) { - pr_warn("map '%s' should be BPF_MAP_TYPE_PERF_EVENT_ARRAY\n", - map.name); - return ERR_PTR(-EINVAL); + /* if BPF_OBJ_GET_INFO_BY_FD is supported, will return + * -EBADFD, -EFAULT, or -E2BIG on real error + */ + if (err != -EINVAL) { + pr_warn("failed to get map info for map FD %d: %s\n", + map_fd, libbpf_strerror_r(err, msg, sizeof(msg))); + return ERR_PTR(err); + } + pr_debug("failed to get map info for FD %d; API not supported? Ignoring...\n", + map_fd); + } else { + if (map.type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) { + pr_warn("map '%s' should be BPF_MAP_TYPE_PERF_EVENT_ARRAY\n", + map.name); + return ERR_PTR(-EINVAL); + } } pb = calloc(1, sizeof(*pb)); @@ -8643,7 +8657,7 @@ static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt, err = pb->cpu_cnt; goto error; } - if (map.max_entries < pb->cpu_cnt) + if (map.max_entries && map.max_entries < pb->cpu_cnt) pb->cpu_cnt = map.max_entries; } diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 6544d2cd1ed63..c5d5c7664c3b7 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -288,4 +288,5 @@ LIBBPF_0.1.0 { bpf_map__value_size; bpf_program__autoload; bpf_program__set_autoload; + btf__set_fd; } LIBBPF_0.0.9; diff --git a/tools/testing/selftests/bpf/prog_tests/core_retro.c b/tools/testing/selftests/bpf/prog_tests/core_retro.c new file mode 100644 index 0000000000000..78e30d3a23d5f --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/core_retro.c @@ -0,0 +1,33 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2020 Facebook +#define _GNU_SOURCE +#include +#include "test_core_retro.skel.h" + +void test_core_retro(void) +{ + int err, zero = 0, res, duration = 0; + struct test_core_retro *skel; + + /* load program */ + skel = test_core_retro__open_and_load(); + if (CHECK(!skel, "skel_load", "skeleton open/load failed\n")) + goto out_close; + + /* attach probe */ + err = test_core_retro__attach(skel); + if (CHECK(err, "attach_kprobe", "err %d\n", err)) + goto out_close; + + /* trigger */ + usleep(1); + + err = bpf_map_lookup_elem(bpf_map__fd(skel->maps.results), &zero, &res); + if (CHECK(err, "map_lookup", "failed to lookup result: %d\n", errno)) + goto out_close; + + CHECK(res != getpid(), "pid_check", "got %d != exp %d\n", res, getpid()); + +out_close: + test_core_retro__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/prog_tests/perf_buffer.c b/tools/testing/selftests/bpf/prog_tests/perf_buffer.c index a122ce3b360eb..c33ec180b3f2d 100644 --- a/tools/testing/selftests/bpf/prog_tests/perf_buffer.c +++ b/tools/testing/selftests/bpf/prog_tests/perf_buffer.c @@ -4,6 +4,7 @@ #include #include #include +#include "test_perf_buffer.skel.h" #include "bpf/libbpf_internal.h" /* AddressSanitizer sometimes crashes due to data dereference below, due to @@ -25,16 +26,11 @@ static void on_sample(void *ctx, int cpu, void *data, __u32 size) void test_perf_buffer(void) { - int err, prog_fd, on_len, nr_on_cpus = 0, nr_cpus, i, duration = 0; - const char *prog_name = "kprobe/sys_nanosleep"; - const char *file = "./test_perf_buffer.o"; + int err, on_len, nr_on_cpus = 0, nr_cpus, i, duration = 0; struct perf_buffer_opts pb_opts = {}; - struct bpf_map *perf_buf_map; + struct test_perf_buffer *skel; cpu_set_t cpu_set, cpu_seen; - struct bpf_program *prog; - struct bpf_object *obj; struct perf_buffer *pb; - struct bpf_link *link; bool *online; nr_cpus = libbpf_num_possible_cpus(); @@ -51,33 +47,21 @@ void test_perf_buffer(void) nr_on_cpus++; /* load program */ - err = bpf_prog_load(file, BPF_PROG_TYPE_KPROBE, &obj, &prog_fd); - if (CHECK(err, "obj_load", "err %d errno %d\n", err, errno)) { - obj = NULL; - goto out_close; - } - - prog = bpf_object__find_program_by_title(obj, prog_name); - if (CHECK(!prog, "find_probe", "prog '%s' not found\n", prog_name)) + skel = test_perf_buffer__open_and_load(); + if (CHECK(!skel, "skel_load", "skeleton open/load failed\n")) goto out_close; - /* load map */ - perf_buf_map = bpf_object__find_map_by_name(obj, "perf_buf_map"); - if (CHECK(!perf_buf_map, "find_perf_buf_map", "not found\n")) - goto out_close; - - /* attach kprobe */ - link = bpf_program__attach_kprobe(prog, false /* retprobe */, - SYS_NANOSLEEP_KPROBE_NAME); - if (CHECK(IS_ERR(link), "attach_kprobe", "err %ld\n", PTR_ERR(link))) + /* attach probe */ + err = test_perf_buffer__attach(skel); + if (CHECK(err, "attach_kprobe", "err %d\n", err)) goto out_close; /* set up perf buffer */ pb_opts.sample_cb = on_sample; pb_opts.ctx = &cpu_seen; - pb = perf_buffer__new(bpf_map__fd(perf_buf_map), 1, &pb_opts); + pb = perf_buffer__new(bpf_map__fd(skel->maps.perf_buf_map), 1, &pb_opts); if (CHECK(IS_ERR(pb), "perf_buf__new", "err %ld\n", PTR_ERR(pb))) - goto out_detach; + goto out_close; /* trigger kprobe on every CPU */ CPU_ZERO(&cpu_seen); @@ -94,7 +78,7 @@ void test_perf_buffer(void) &cpu_set); if (err && CHECK(err, "set_affinity", "cpu #%d, err %d\n", i, err)) - goto out_detach; + goto out_close; usleep(1); } @@ -110,9 +94,7 @@ void test_perf_buffer(void) out_free_pb: perf_buffer__free(pb); -out_detach: - bpf_link__destroy(link); out_close: - bpf_object__close(obj); + test_perf_buffer__destroy(skel); free(online); } diff --git a/tools/testing/selftests/bpf/progs/test_core_retro.c b/tools/testing/selftests/bpf/progs/test_core_retro.c new file mode 100644 index 0000000000000..75c60c3c29cf6 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_core_retro.c @@ -0,0 +1,30 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2020 Facebook +#include +#include +#include + +struct task_struct { + int tgid; +} __attribute__((preserve_access_index)); + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __type(key, int); + __type(value, int); +} results SEC(".maps"); + +SEC("tp/raw_syscalls/sys_enter") +int handle_sys_enter(void *ctx) +{ + struct task_struct *task = (void *)bpf_get_current_task(); + int tgid = BPF_CORE_READ(task, tgid); + int zero = 0; + + bpf_map_update_elem(&results, &zero, &tgid, 0); + + return 0; +} + +char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/progs/test_perf_buffer.c b/tools/testing/selftests/bpf/progs/test_perf_buffer.c index ad59c4c9aba8b..8207a2dc2f9da 100644 --- a/tools/testing/selftests/bpf/progs/test_perf_buffer.c +++ b/tools/testing/selftests/bpf/progs/test_perf_buffer.c @@ -12,8 +12,8 @@ struct { __uint(value_size, sizeof(int)); } perf_buf_map SEC(".maps"); -SEC("kprobe/sys_nanosleep") -int BPF_KPROBE(handle_sys_nanosleep_entry) +SEC("tp/raw_syscalls/sys_enter") +int handle_sys_enter(void *ctx) { int cpu = bpf_get_smp_processor_id();