From: Martin KaFai Lau kafai@fb.com
mainline inclusion from mainline-5.13-rc1 commit 933d1aa32409ef4209c8065ee4ede68236659cd2 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I5EUVD CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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This patch refactors most of the logic from bpf_object__resolve_ksyms_btf_id() into a new function bpf_object__resolve_ksym_var_btf_id(). It is to get ready for a later patch adding bpf_object__resolve_ksym_func_btf_id() which resolves a kernel function to the running kernel btf_id.
Signed-off-by: Martin KaFai Lau kafai@fb.com Signed-off-by: Alexei Starovoitov ast@kernel.org Acked-by: Andrii Nakryiko andrii@kernel.org Link: https://lore.kernel.org/bpf/20210325015207.1546749-1-kafai@fb.com (cherry picked from commit 933d1aa32409ef4209c8065ee4ede68236659cd2) Signed-off-by: Wang Yufen wangyufen@huawei.com --- tools/lib/bpf/libbpf.c | 124 ++++++++++++++++++++++------------------- 1 file changed, 67 insertions(+), 57 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 0c1c6de1e0b3..9a0dec536abf 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -7452,75 +7452,85 @@ static int bpf_object__read_kallsyms_file(struct bpf_object *obj) return err; }
-static int bpf_object__resolve_ksyms_btf_id(struct bpf_object *obj) +static int bpf_object__resolve_ksym_var_btf_id(struct bpf_object *obj, + struct extern_desc *ext) { - struct extern_desc *ext; + const struct btf_type *targ_var, *targ_type; + __u32 targ_type_id, local_type_id; + const char *targ_var_name; + int i, id, btf_fd, err; struct btf *btf; - int i, j, id, btf_fd, err;
- for (i = 0; i < obj->nr_extern; i++) { - const struct btf_type *targ_var, *targ_type; - __u32 targ_type_id, local_type_id; - const char *targ_var_name; - int ret; + btf = obj->btf_vmlinux; + btf_fd = 0; + id = btf__find_by_name_kind(btf, ext->name, BTF_KIND_VAR); + if (id == -ENOENT) { + err = load_module_btfs(obj); + if (err) + return err;
- ext = &obj->externs[i]; - if (ext->type != EXT_KSYM || !ext->ksym.type_id) - continue; + for (i = 0; i < obj->btf_module_cnt; i++) { + btf = obj->btf_modules[i].btf; + /* we assume module BTF FD is always >0 */ + btf_fd = obj->btf_modules[i].fd; + id = btf__find_by_name_kind(btf, ext->name, BTF_KIND_VAR); + if (id != -ENOENT) + break; + } + } + if (id <= 0) { + pr_warn("extern (var ksym) '%s': failed to find BTF ID in kernel BTF(s).\n", + ext->name); + return -ESRCH; + }
- btf = obj->btf_vmlinux; - btf_fd = 0; - id = btf__find_by_name_kind(btf, ext->name, BTF_KIND_VAR); - if (id == -ENOENT) { - err = load_module_btfs(obj); - if (err) - return err; + /* find local type_id */ + local_type_id = ext->ksym.type_id;
- for (j = 0; j < obj->btf_module_cnt; j++) { - btf = obj->btf_modules[j].btf; - /* we assume module BTF FD is always >0 */ - btf_fd = obj->btf_modules[j].fd; - id = btf__find_by_name_kind(btf, ext->name, BTF_KIND_VAR); - if (id != -ENOENT) - break; - } - } - if (id <= 0) { - pr_warn("extern (ksym) '%s': failed to find BTF ID in kernel BTF(s).\n", - ext->name); - return -ESRCH; - } + /* find target type_id */ + targ_var = btf__type_by_id(btf, id); + targ_var_name = btf__name_by_offset(btf, targ_var->name_off); + targ_type = skip_mods_and_typedefs(btf, targ_var->type, &targ_type_id);
- /* find local type_id */ - local_type_id = ext->ksym.type_id; + err = bpf_core_types_are_compat(obj->btf, local_type_id, + btf, targ_type_id); + if (err <= 0) { + const struct btf_type *local_type; + const char *targ_name, *local_name;
- /* find target type_id */ - targ_var = btf__type_by_id(btf, id); - targ_var_name = btf__name_by_offset(btf, targ_var->name_off); - targ_type = skip_mods_and_typedefs(btf, targ_var->type, &targ_type_id); + local_type = btf__type_by_id(obj->btf, local_type_id); + local_name = btf__name_by_offset(obj->btf, local_type->name_off); + targ_name = btf__name_by_offset(btf, targ_type->name_off);
- ret = bpf_core_types_are_compat(obj->btf, local_type_id, - btf, targ_type_id); - if (ret <= 0) { - const struct btf_type *local_type; - const char *targ_name, *local_name; + pr_warn("extern (var ksym) '%s': incompatible types, expected [%d] %s %s, but kernel has [%d] %s %s\n", + ext->name, local_type_id, + btf_kind_str(local_type), local_name, targ_type_id, + btf_kind_str(targ_type), targ_name); + return -EINVAL; + }
- local_type = btf__type_by_id(obj->btf, local_type_id); - local_name = btf__name_by_offset(obj->btf, local_type->name_off); - targ_name = btf__name_by_offset(btf, targ_type->name_off); + ext->is_set = true; + ext->ksym.kernel_btf_obj_fd = btf_fd; + ext->ksym.kernel_btf_id = id; + pr_debug("extern (var ksym) '%s': resolved to [%d] %s %s\n", + ext->name, id, btf_kind_str(targ_var), targ_var_name);
- pr_warn("extern (ksym) '%s': incompatible types, expected [%d] %s %s, but kernel has [%d] %s %s\n", - ext->name, local_type_id, - btf_kind_str(local_type), local_name, targ_type_id, - btf_kind_str(targ_type), targ_name); - return -EINVAL; - } + return 0; +} + +static int bpf_object__resolve_ksyms_btf_id(struct bpf_object *obj) +{ + struct extern_desc *ext; + int i, err; + + for (i = 0; i < obj->nr_extern; i++) { + ext = &obj->externs[i]; + if (ext->type != EXT_KSYM || !ext->ksym.type_id) + continue;
- ext->is_set = true; - ext->ksym.kernel_btf_obj_fd = btf_fd; - ext->ksym.kernel_btf_id = id; - pr_debug("extern (ksym) '%s': resolved to [%d] %s %s\n", - ext->name, id, btf_kind_str(targ_var), targ_var_name); + err = bpf_object__resolve_ksym_var_btf_id(obj, ext); + if (err) + return err; } return 0; }