From 41ced4cd88020c9d4b71ff7c50d020f081efa4a0 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Tue, 14 Sep 2021 15:30:09 -0700 Subject: [PATCH 01/11] btf: Change BTF_KIND_* macros to enums Change BTF_KIND_* macros to enums so they are encoded in dwarf and appear in vmlinux.h. This will make it easier for bpf programs to use these constants without macro definitions. Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210914223009.245307-1-yhs@fb.com --- include/uapi/linux/btf.h | 41 ++++++++++++++++++---------------- tools/include/uapi/linux/btf.h | 41 ++++++++++++++++++---------------- 2 files changed, 44 insertions(+), 38 deletions(-) diff --git a/include/uapi/linux/btf.h b/include/uapi/linux/btf.h index d27b1708efe9..10e401073dd1 100644 --- a/include/uapi/linux/btf.h +++ b/include/uapi/linux/btf.h @@ -56,25 +56,28 @@ struct btf_type { #define BTF_INFO_VLEN(info) ((info) & 0xffff) #define BTF_INFO_KFLAG(info) ((info) >> 31) -#define BTF_KIND_UNKN 0 /* Unknown */ -#define BTF_KIND_INT 1 /* Integer */ -#define BTF_KIND_PTR 2 /* Pointer */ -#define BTF_KIND_ARRAY 3 /* Array */ -#define BTF_KIND_STRUCT 4 /* Struct */ -#define BTF_KIND_UNION 5 /* Union */ -#define BTF_KIND_ENUM 6 /* Enumeration */ -#define BTF_KIND_FWD 7 /* Forward */ -#define BTF_KIND_TYPEDEF 8 /* Typedef */ -#define BTF_KIND_VOLATILE 9 /* Volatile */ -#define BTF_KIND_CONST 10 /* Const */ -#define BTF_KIND_RESTRICT 11 /* Restrict */ -#define BTF_KIND_FUNC 12 /* Function */ -#define BTF_KIND_FUNC_PROTO 13 /* Function Proto */ -#define BTF_KIND_VAR 14 /* Variable */ -#define BTF_KIND_DATASEC 15 /* Section */ -#define BTF_KIND_FLOAT 16 /* Floating point */ -#define BTF_KIND_MAX BTF_KIND_FLOAT -#define NR_BTF_KINDS (BTF_KIND_MAX + 1) +enum { + BTF_KIND_UNKN = 0, /* Unknown */ + BTF_KIND_INT = 1, /* Integer */ + BTF_KIND_PTR = 2, /* Pointer */ + BTF_KIND_ARRAY = 3, /* Array */ + BTF_KIND_STRUCT = 4, /* Struct */ + BTF_KIND_UNION = 5, /* Union */ + BTF_KIND_ENUM = 6, /* Enumeration */ + BTF_KIND_FWD = 7, /* Forward */ + BTF_KIND_TYPEDEF = 8, /* Typedef */ + BTF_KIND_VOLATILE = 9, /* Volatile */ + BTF_KIND_CONST = 10, /* Const */ + BTF_KIND_RESTRICT = 11, /* Restrict */ + BTF_KIND_FUNC = 12, /* Function */ + BTF_KIND_FUNC_PROTO = 13, /* Function Proto */ + BTF_KIND_VAR = 14, /* Variable */ + BTF_KIND_DATASEC = 15, /* Section */ + BTF_KIND_FLOAT = 16, /* Floating point */ + + NR_BTF_KINDS, + BTF_KIND_MAX = NR_BTF_KINDS - 1, +}; /* For some specific BTF_KIND, "struct btf_type" is immediately * followed by extra data. diff --git a/tools/include/uapi/linux/btf.h b/tools/include/uapi/linux/btf.h index d27b1708efe9..10e401073dd1 100644 --- a/tools/include/uapi/linux/btf.h +++ b/tools/include/uapi/linux/btf.h @@ -56,25 +56,28 @@ struct btf_type { #define BTF_INFO_VLEN(info) ((info) & 0xffff) #define BTF_INFO_KFLAG(info) ((info) >> 31) -#define BTF_KIND_UNKN 0 /* Unknown */ -#define BTF_KIND_INT 1 /* Integer */ -#define BTF_KIND_PTR 2 /* Pointer */ -#define BTF_KIND_ARRAY 3 /* Array */ -#define BTF_KIND_STRUCT 4 /* Struct */ -#define BTF_KIND_UNION 5 /* Union */ -#define BTF_KIND_ENUM 6 /* Enumeration */ -#define BTF_KIND_FWD 7 /* Forward */ -#define BTF_KIND_TYPEDEF 8 /* Typedef */ -#define BTF_KIND_VOLATILE 9 /* Volatile */ -#define BTF_KIND_CONST 10 /* Const */ -#define BTF_KIND_RESTRICT 11 /* Restrict */ -#define BTF_KIND_FUNC 12 /* Function */ -#define BTF_KIND_FUNC_PROTO 13 /* Function Proto */ -#define BTF_KIND_VAR 14 /* Variable */ -#define BTF_KIND_DATASEC 15 /* Section */ -#define BTF_KIND_FLOAT 16 /* Floating point */ -#define BTF_KIND_MAX BTF_KIND_FLOAT -#define NR_BTF_KINDS (BTF_KIND_MAX + 1) +enum { + BTF_KIND_UNKN = 0, /* Unknown */ + BTF_KIND_INT = 1, /* Integer */ + BTF_KIND_PTR = 2, /* Pointer */ + BTF_KIND_ARRAY = 3, /* Array */ + BTF_KIND_STRUCT = 4, /* Struct */ + BTF_KIND_UNION = 5, /* Union */ + BTF_KIND_ENUM = 6, /* Enumeration */ + BTF_KIND_FWD = 7, /* Forward */ + BTF_KIND_TYPEDEF = 8, /* Typedef */ + BTF_KIND_VOLATILE = 9, /* Volatile */ + BTF_KIND_CONST = 10, /* Const */ + BTF_KIND_RESTRICT = 11, /* Restrict */ + BTF_KIND_FUNC = 12, /* Function */ + BTF_KIND_FUNC_PROTO = 13, /* Function Proto */ + BTF_KIND_VAR = 14, /* Variable */ + BTF_KIND_DATASEC = 15, /* Section */ + BTF_KIND_FLOAT = 16, /* Floating point */ + + NR_BTF_KINDS, + BTF_KIND_MAX = NR_BTF_KINDS - 1, +}; /* For some specific BTF_KIND, "struct btf_type" is immediately * followed by extra data. From b5ea834dde6b6e7f75e51d5f66dac8cd7c97b5ef Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Tue, 14 Sep 2021 15:30:15 -0700 Subject: [PATCH 02/11] bpf: Support for new btf kind BTF_KIND_TAG LLVM14 added support for a new C attribute ([1]) __attribute__((btf_tag("arbitrary_str"))) This attribute will be emitted to dwarf ([2]) and pahole will convert it to BTF. Or for bpf target, this attribute will be emitted to BTF directly ([3], [4]). The attribute is intended to provide additional information for - struct/union type or struct/union member - static/global variables - static/global function or function parameter. For linux kernel, the btf_tag can be applied in various places to specify user pointer, function pre- or post- condition, function allow/deny in certain context, etc. Such information will be encoded in vmlinux BTF and can be used by verifier. The btf_tag can also be applied to bpf programs to help global verifiable functions, e.g., specifying preconditions, etc. This patch added basic parsing and checking support in kernel for new BTF_KIND_TAG kind. [1] https://reviews.llvm.org/D106614 [2] https://reviews.llvm.org/D106621 [3] https://reviews.llvm.org/D106622 [4] https://reviews.llvm.org/D109560 Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210914223015.245546-1-yhs@fb.com --- include/uapi/linux/btf.h | 14 +++- kernel/bpf/btf.c | 128 +++++++++++++++++++++++++++++++++ tools/include/uapi/linux/btf.h | 14 +++- 3 files changed, 154 insertions(+), 2 deletions(-) diff --git a/include/uapi/linux/btf.h b/include/uapi/linux/btf.h index 10e401073dd1..642b6ecb37d7 100644 --- a/include/uapi/linux/btf.h +++ b/include/uapi/linux/btf.h @@ -43,7 +43,7 @@ struct btf_type { * "size" tells the size of the type it is describing. * * "type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT, - * FUNC, FUNC_PROTO and VAR. + * FUNC, FUNC_PROTO, VAR and TAG. * "type" is a type_id referring to another type. */ union { @@ -74,6 +74,7 @@ enum { BTF_KIND_VAR = 14, /* Variable */ BTF_KIND_DATASEC = 15, /* Section */ BTF_KIND_FLOAT = 16, /* Floating point */ + BTF_KIND_TAG = 17, /* Tag */ NR_BTF_KINDS, BTF_KIND_MAX = NR_BTF_KINDS - 1, @@ -173,4 +174,15 @@ struct btf_var_secinfo { __u32 size; }; +/* BTF_KIND_TAG is followed by a single "struct btf_tag" to describe + * additional information related to the tag applied location. + * If component_idx == -1, the tag is applied to a struct, union, + * variable or function. Otherwise, it is applied to a struct/union + * member or a func argument, and component_idx indicates which member + * or argument (0 ... vlen-1). + */ +struct btf_tag { + __s32 component_idx; +}; + #endif /* _UAPI__LINUX_BTF_H__ */ diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index dfe61df4f974..c3d605b22473 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -281,6 +281,7 @@ static const char * const btf_kind_str[NR_BTF_KINDS] = { [BTF_KIND_VAR] = "VAR", [BTF_KIND_DATASEC] = "DATASEC", [BTF_KIND_FLOAT] = "FLOAT", + [BTF_KIND_TAG] = "TAG", }; const char *btf_type_str(const struct btf_type *t) @@ -459,6 +460,17 @@ static bool btf_type_is_datasec(const struct btf_type *t) return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC; } +static bool btf_type_is_tag(const struct btf_type *t) +{ + return BTF_INFO_KIND(t->info) == BTF_KIND_TAG; +} + +static bool btf_type_is_tag_target(const struct btf_type *t) +{ + return btf_type_is_func(t) || btf_type_is_struct(t) || + btf_type_is_var(t); +} + u32 btf_nr_types(const struct btf *btf) { u32 total = 0; @@ -537,6 +549,7 @@ const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf, static bool btf_type_is_resolve_source_only(const struct btf_type *t) { return btf_type_is_var(t) || + btf_type_is_tag(t) || btf_type_is_datasec(t); } @@ -563,6 +576,7 @@ static bool btf_type_needs_resolve(const struct btf_type *t) btf_type_is_struct(t) || btf_type_is_array(t) || btf_type_is_var(t) || + btf_type_is_tag(t) || btf_type_is_datasec(t); } @@ -616,6 +630,11 @@ static const struct btf_var *btf_type_var(const struct btf_type *t) return (const struct btf_var *)(t + 1); } +static const struct btf_tag *btf_type_tag(const struct btf_type *t) +{ + return (const struct btf_tag *)(t + 1); +} + static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t) { return kind_ops[BTF_INFO_KIND(t->info)]; @@ -3801,6 +3820,110 @@ static const struct btf_kind_operations float_ops = { .show = btf_df_show, }; +static s32 btf_tag_check_meta(struct btf_verifier_env *env, + const struct btf_type *t, + u32 meta_left) +{ + const struct btf_tag *tag; + u32 meta_needed = sizeof(*tag); + s32 component_idx; + const char *value; + + if (meta_left < meta_needed) { + btf_verifier_log_basic(env, t, + "meta_left:%u meta_needed:%u", + meta_left, meta_needed); + return -EINVAL; + } + + value = btf_name_by_offset(env->btf, t->name_off); + if (!value || !value[0]) { + btf_verifier_log_type(env, t, "Invalid value"); + return -EINVAL; + } + + if (btf_type_vlen(t)) { + btf_verifier_log_type(env, t, "vlen != 0"); + return -EINVAL; + } + + if (btf_type_kflag(t)) { + btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); + return -EINVAL; + } + + component_idx = btf_type_tag(t)->component_idx; + if (component_idx < -1) { + btf_verifier_log_type(env, t, "Invalid component_idx"); + return -EINVAL; + } + + btf_verifier_log_type(env, t, NULL); + + return meta_needed; +} + +static int btf_tag_resolve(struct btf_verifier_env *env, + const struct resolve_vertex *v) +{ + const struct btf_type *next_type; + const struct btf_type *t = v->t; + u32 next_type_id = t->type; + struct btf *btf = env->btf; + s32 component_idx; + u32 vlen; + + next_type = btf_type_by_id(btf, next_type_id); + if (!next_type || !btf_type_is_tag_target(next_type)) { + btf_verifier_log_type(env, v->t, "Invalid type_id"); + return -EINVAL; + } + + if (!env_type_is_resolve_sink(env, next_type) && + !env_type_is_resolved(env, next_type_id)) + return env_stack_push(env, next_type, next_type_id); + + component_idx = btf_type_tag(t)->component_idx; + if (component_idx != -1) { + if (btf_type_is_var(next_type)) { + btf_verifier_log_type(env, v->t, "Invalid component_idx"); + return -EINVAL; + } + + if (btf_type_is_struct(next_type)) { + vlen = btf_type_vlen(next_type); + } else { + /* next_type should be a function */ + next_type = btf_type_by_id(btf, next_type->type); + vlen = btf_type_vlen(next_type); + } + + if ((u32)component_idx >= vlen) { + btf_verifier_log_type(env, v->t, "Invalid component_idx"); + return -EINVAL; + } + } + + env_stack_pop_resolved(env, next_type_id, 0); + + return 0; +} + +static void btf_tag_log(struct btf_verifier_env *env, const struct btf_type *t) +{ + btf_verifier_log(env, "type=%u component_idx=%d", t->type, + btf_type_tag(t)->component_idx); +} + +static const struct btf_kind_operations tag_ops = { + .check_meta = btf_tag_check_meta, + .resolve = btf_tag_resolve, + .check_member = btf_df_check_member, + .check_kflag_member = btf_df_check_kflag_member, + .log_details = btf_tag_log, + .show = btf_df_show, +}; + static int btf_func_proto_check(struct btf_verifier_env *env, const struct btf_type *t) { @@ -3935,6 +4058,7 @@ static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = { [BTF_KIND_VAR] = &var_ops, [BTF_KIND_DATASEC] = &datasec_ops, [BTF_KIND_FLOAT] = &float_ops, + [BTF_KIND_TAG] = &tag_ops, }; static s32 btf_check_meta(struct btf_verifier_env *env, @@ -4019,6 +4143,10 @@ static bool btf_resolve_valid(struct btf_verifier_env *env, return !btf_resolved_type_id(btf, type_id) && !btf_resolved_type_size(btf, type_id); + if (btf_type_is_tag(t)) + return btf_resolved_type_id(btf, type_id) && + !btf_resolved_type_size(btf, type_id); + if (btf_type_is_modifier(t) || btf_type_is_ptr(t) || btf_type_is_var(t)) { t = btf_type_id_resolve(btf, &type_id); diff --git a/tools/include/uapi/linux/btf.h b/tools/include/uapi/linux/btf.h index 10e401073dd1..642b6ecb37d7 100644 --- a/tools/include/uapi/linux/btf.h +++ b/tools/include/uapi/linux/btf.h @@ -43,7 +43,7 @@ struct btf_type { * "size" tells the size of the type it is describing. * * "type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT, - * FUNC, FUNC_PROTO and VAR. + * FUNC, FUNC_PROTO, VAR and TAG. * "type" is a type_id referring to another type. */ union { @@ -74,6 +74,7 @@ enum { BTF_KIND_VAR = 14, /* Variable */ BTF_KIND_DATASEC = 15, /* Section */ BTF_KIND_FLOAT = 16, /* Floating point */ + BTF_KIND_TAG = 17, /* Tag */ NR_BTF_KINDS, BTF_KIND_MAX = NR_BTF_KINDS - 1, @@ -173,4 +174,15 @@ struct btf_var_secinfo { __u32 size; }; +/* BTF_KIND_TAG is followed by a single "struct btf_tag" to describe + * additional information related to the tag applied location. + * If component_idx == -1, the tag is applied to a struct, union, + * variable or function. Otherwise, it is applied to a struct/union + * member or a func argument, and component_idx indicates which member + * or argument (0 ... vlen-1). + */ +struct btf_tag { + __s32 component_idx; +}; + #endif /* _UAPI__LINUX_BTF_H__ */ From 30025e8bd80fdc5a4159ec7f9511121ea561f456 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Tue, 14 Sep 2021 15:30:20 -0700 Subject: [PATCH 03/11] libbpf: Rename btf_{hash,equal}_int to btf_{hash,equal}_int_tag This patch renames functions btf_{hash,equal}_int() to btf_{hash,equal}_int_tag() so they can be reused for BTF_KIND_TAG support. There is no functionality change for this patch. Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210914223020.245829-1-yhs@fb.com --- tools/lib/bpf/btf.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 77dc24d58302..7cb6ebf1be37 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -3256,8 +3256,8 @@ static bool btf_equal_common(struct btf_type *t1, struct btf_type *t2) t1->size == t2->size; } -/* Calculate type signature hash of INT. */ -static long btf_hash_int(struct btf_type *t) +/* Calculate type signature hash of INT or TAG. */ +static long btf_hash_int_tag(struct btf_type *t) { __u32 info = *(__u32 *)(t + 1); long h; @@ -3267,8 +3267,8 @@ static long btf_hash_int(struct btf_type *t) return h; } -/* Check structural equality of two INTs. */ -static bool btf_equal_int(struct btf_type *t1, struct btf_type *t2) +/* Check structural equality of two INTs or TAGs. */ +static bool btf_equal_int_tag(struct btf_type *t1, struct btf_type *t2) { __u32 info1, info2; @@ -3535,7 +3535,7 @@ static int btf_dedup_prep(struct btf_dedup *d) h = btf_hash_common(t); break; case BTF_KIND_INT: - h = btf_hash_int(t); + h = btf_hash_int_tag(t); break; case BTF_KIND_ENUM: h = btf_hash_enum(t); @@ -3593,11 +3593,11 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) return 0; case BTF_KIND_INT: - h = btf_hash_int(t); + h = btf_hash_int_tag(t); for_each_dedup_cand(d, hash_entry, h) { cand_id = (__u32)(long)hash_entry->value; cand = btf_type_by_id(d->btf, cand_id); - if (btf_equal_int(t, cand)) { + if (btf_equal_int_tag(t, cand)) { new_id = cand_id; break; } @@ -3881,7 +3881,7 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id, switch (cand_kind) { case BTF_KIND_INT: - return btf_equal_int(cand_type, canon_type); + return btf_equal_int_tag(cand_type, canon_type); case BTF_KIND_ENUM: if (d->opts.dont_resolve_fwds) From 5b84bd10363e36ceb7c4c1ae749a3fc8adf8df45 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Tue, 14 Sep 2021 15:30:25 -0700 Subject: [PATCH 04/11] libbpf: Add support for BTF_KIND_TAG Add BTF_KIND_TAG support for parsing and dedup. Also added sanitization for BTF_KIND_TAG. If BTF_KIND_TAG is not supported in the kernel, sanitize it to INTs. Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210914223025.246687-1-yhs@fb.com --- tools/lib/bpf/btf.c | 68 +++++++++++++++++++++++++++++++++ tools/lib/bpf/btf.h | 15 ++++++++ tools/lib/bpf/btf_dump.c | 3 ++ tools/lib/bpf/libbpf.c | 31 +++++++++++++-- tools/lib/bpf/libbpf.map | 2 + tools/lib/bpf/libbpf_internal.h | 2 + 6 files changed, 118 insertions(+), 3 deletions(-) diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 7cb6ebf1be37..6ad63e4d418a 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -304,6 +304,8 @@ static int btf_type_size(const struct btf_type *t) return base_size + sizeof(struct btf_var); case BTF_KIND_DATASEC: return base_size + vlen * sizeof(struct btf_var_secinfo); + case BTF_KIND_TAG: + return base_size + sizeof(struct btf_tag); default: pr_debug("Unsupported BTF_KIND:%u\n", btf_kind(t)); return -EINVAL; @@ -376,6 +378,9 @@ static int btf_bswap_type_rest(struct btf_type *t) v->size = bswap_32(v->size); } return 0; + case BTF_KIND_TAG: + btf_tag(t)->component_idx = bswap_32(btf_tag(t)->component_idx); + return 0; default: pr_debug("Unsupported BTF_KIND:%u\n", btf_kind(t)); return -EINVAL; @@ -586,6 +591,7 @@ __s64 btf__resolve_size(const struct btf *btf, __u32 type_id) case BTF_KIND_CONST: case BTF_KIND_RESTRICT: case BTF_KIND_VAR: + case BTF_KIND_TAG: type_id = t->type; break; case BTF_KIND_ARRAY: @@ -2440,6 +2446,48 @@ int btf__add_datasec_var_info(struct btf *btf, int var_type_id, __u32 offset, __ return 0; } +/* + * Append new BTF_KIND_TAG type with: + * - *value* - non-empty/non-NULL string; + * - *ref_type_id* - referenced type ID, it might not exist yet; + * - *component_idx* - -1 for tagging reference type, otherwise struct/union + * member or function argument index; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_tag(struct btf *btf, const char *value, int ref_type_id, + int component_idx) +{ + struct btf_type *t; + int sz, value_off; + + if (!value || !value[0] || component_idx < -1) + return libbpf_err(-EINVAL); + + if (validate_type_id(ref_type_id)) + return libbpf_err(-EINVAL); + + if (btf_ensure_modifiable(btf)) + return libbpf_err(-ENOMEM); + + sz = sizeof(struct btf_type) + sizeof(struct btf_tag); + t = btf_add_type_mem(btf, sz); + if (!t) + return libbpf_err(-ENOMEM); + + value_off = btf__add_str(btf, value); + if (value_off < 0) + return value_off; + + t->name_off = value_off; + t->info = btf_type_info(BTF_KIND_TAG, 0, false); + t->type = ref_type_id; + btf_tag(t)->component_idx = component_idx; + + return btf_commit_type(btf, sz); +} + struct btf_ext_sec_setup_param { __u32 off; __u32 len; @@ -3535,6 +3583,7 @@ static int btf_dedup_prep(struct btf_dedup *d) h = btf_hash_common(t); break; case BTF_KIND_INT: + case BTF_KIND_TAG: h = btf_hash_int_tag(t); break; case BTF_KIND_ENUM: @@ -3590,6 +3639,7 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) case BTF_KIND_FUNC_PROTO: case BTF_KIND_VAR: case BTF_KIND_DATASEC: + case BTF_KIND_TAG: return 0; case BTF_KIND_INT: @@ -4210,6 +4260,23 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) } break; + case BTF_KIND_TAG: + ref_type_id = btf_dedup_ref_type(d, t->type); + if (ref_type_id < 0) + return ref_type_id; + t->type = ref_type_id; + + h = btf_hash_int_tag(t); + for_each_dedup_cand(d, hash_entry, h) { + cand_id = (__u32)(long)hash_entry->value; + cand = btf_type_by_id(d->btf, cand_id); + if (btf_equal_int_tag(t, cand)) { + new_id = cand_id; + break; + } + } + break; + case BTF_KIND_ARRAY: { struct btf_array *info = btf_array(t); @@ -4482,6 +4549,7 @@ int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ct case BTF_KIND_TYPEDEF: case BTF_KIND_FUNC: case BTF_KIND_VAR: + case BTF_KIND_TAG: return visit(&t->type, ctx); case BTF_KIND_ARRAY: { diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index f2e2fab950b7..659ea8a2769b 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -143,6 +143,10 @@ LIBBPF_API int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz LIBBPF_API int btf__add_datasec_var_info(struct btf *btf, int var_type_id, __u32 offset, __u32 byte_sz); +/* tag construction API */ +LIBBPF_API int btf__add_tag(struct btf *btf, const char *value, int ref_type_id, + int component_idx); + struct btf_dedup_opts { unsigned int dedup_table_size; bool dont_resolve_fwds; @@ -330,6 +334,11 @@ static inline bool btf_is_float(const struct btf_type *t) return btf_kind(t) == BTF_KIND_FLOAT; } +static inline bool btf_is_tag(const struct btf_type *t) +{ + return btf_kind(t) == BTF_KIND_TAG; +} + static inline __u8 btf_int_encoding(const struct btf_type *t) { return BTF_INT_ENCODING(*(__u32 *)(t + 1)); @@ -398,6 +407,12 @@ btf_var_secinfos(const struct btf_type *t) return (struct btf_var_secinfo *)(t + 1); } +struct btf_tag; +static inline struct btf_tag *btf_tag(const struct btf_type *t) +{ + return (struct btf_tag *)(t + 1); +} + #ifdef __cplusplus } /* extern "C" */ #endif diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index e4b483f15fb9..ad6df97295ae 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -316,6 +316,7 @@ static int btf_dump_mark_referenced(struct btf_dump *d) case BTF_KIND_TYPEDEF: case BTF_KIND_FUNC: case BTF_KIND_VAR: + case BTF_KIND_TAG: d->type_states[t->type].referenced = 1; break; @@ -583,6 +584,7 @@ static int btf_dump_order_type(struct btf_dump *d, __u32 id, bool through_ptr) case BTF_KIND_FUNC: case BTF_KIND_VAR: case BTF_KIND_DATASEC: + case BTF_KIND_TAG: d->type_states[id].order_state = ORDERED; return 0; @@ -2215,6 +2217,7 @@ static int btf_dump_dump_type_data(struct btf_dump *d, case BTF_KIND_FWD: case BTF_KIND_FUNC: case BTF_KIND_FUNC_PROTO: + case BTF_KIND_TAG: err = btf_dump_unsupported_data(d, t, id); break; case BTF_KIND_INT: diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 62ed073ea944..62a43c408d73 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -195,6 +195,8 @@ enum kern_feature_id { FEAT_BTF_FLOAT, /* BPF perf link support */ FEAT_PERF_LINK, + /* BTF_KIND_TAG support */ + FEAT_BTF_TAG, __FEAT_CNT, }; @@ -1986,6 +1988,7 @@ static const char *__btf_kind_str(__u16 kind) case BTF_KIND_VAR: return "var"; case BTF_KIND_DATASEC: return "datasec"; case BTF_KIND_FLOAT: return "float"; + case BTF_KIND_TAG: return "tag"; default: return "unknown"; } } @@ -2485,8 +2488,9 @@ static bool btf_needs_sanitization(struct bpf_object *obj) bool has_datasec = kernel_supports(obj, FEAT_BTF_DATASEC); bool has_float = kernel_supports(obj, FEAT_BTF_FLOAT); bool has_func = kernel_supports(obj, FEAT_BTF_FUNC); + bool has_tag = kernel_supports(obj, FEAT_BTF_TAG); - return !has_func || !has_datasec || !has_func_global || !has_float; + return !has_func || !has_datasec || !has_func_global || !has_float || !has_tag; } static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf) @@ -2495,14 +2499,15 @@ static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf) bool has_datasec = kernel_supports(obj, FEAT_BTF_DATASEC); bool has_float = kernel_supports(obj, FEAT_BTF_FLOAT); bool has_func = kernel_supports(obj, FEAT_BTF_FUNC); + bool has_tag = kernel_supports(obj, FEAT_BTF_TAG); struct btf_type *t; int i, j, vlen; for (i = 1; i <= btf__get_nr_types(btf); i++) { t = (struct btf_type *)btf__type_by_id(btf, i); - if (!has_datasec && btf_is_var(t)) { - /* replace VAR with INT */ + if ((!has_datasec && btf_is_var(t)) || (!has_tag && btf_is_tag(t))) { + /* replace VAR/TAG with INT */ t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0); /* * using size = 1 is the safest choice, 4 will be too @@ -4212,6 +4217,23 @@ static int probe_kern_btf_float(void) strs, sizeof(strs))); } +static int probe_kern_btf_tag(void) +{ + static const char strs[] = "\0tag"; + __u32 types[] = { + /* int */ + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + /* VAR x */ /* [2] */ + BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1), + BTF_VAR_STATIC, + /* attr */ + BTF_TYPE_TAG_ENC(1, 2, -1), + }; + + return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), + strs, sizeof(strs))); +} + static int probe_kern_array_mmap(void) { struct bpf_create_map_attr attr = { @@ -4428,6 +4450,9 @@ static struct kern_feature_desc { [FEAT_PERF_LINK] = { "BPF perf link support", probe_perf_link, }, + [FEAT_BTF_TAG] = { + "BTF_KIND_TAG support", probe_kern_btf_tag, + }, }; static bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id) diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 78ea62c9346f..9e649cf9e771 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -388,4 +388,6 @@ LIBBPF_0.5.0 { } LIBBPF_0.4.0; LIBBPF_0.6.0 { + global: + btf__add_tag; } LIBBPF_0.5.0; diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 4f6ff5c23695..ceb0c98979bc 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -69,6 +69,8 @@ #define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size) #define BTF_TYPE_FLOAT_ENC(name, sz) \ BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz) +#define BTF_TYPE_TAG_ENC(value, type, component_idx) \ + BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_TAG, 0, 0), type), (component_idx) #ifndef likely #define likely(x) __builtin_expect(!!(x), 1) From 5c07f2fec00361fb5e8cff8ba7fdede7b29f38bd Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Tue, 14 Sep 2021 15:30:31 -0700 Subject: [PATCH 05/11] bpftool: Add support for BTF_KIND_TAG Added bpftool support to dump BTF_KIND_TAG information. The new bpftool will be used in later patches to dump btf in the test bpf program object file. Currently, the tags are not emitted with bpftool btf dump file format c and they are silently ignored. The tag information is mostly used in the kernel for verification purpose and the kernel uses its own btf to check. With adding these tags to vmlinux.h, tags will be encoded in program's btf but they will not be used by the kernel, at least for now. So let us delay adding these tags to format C header files until there is a real need. Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210914223031.246951-1-yhs@fb.com --- tools/bpf/bpftool/btf.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c index f7e5ff3586c9..49743ad96851 100644 --- a/tools/bpf/bpftool/btf.c +++ b/tools/bpf/bpftool/btf.c @@ -37,6 +37,7 @@ static const char * const btf_kind_str[NR_BTF_KINDS] = { [BTF_KIND_VAR] = "VAR", [BTF_KIND_DATASEC] = "DATASEC", [BTF_KIND_FLOAT] = "FLOAT", + [BTF_KIND_TAG] = "TAG", }; struct btf_attach_table { @@ -347,6 +348,17 @@ static int dump_btf_type(const struct btf *btf, __u32 id, printf(" size=%u", t->size); break; } + case BTF_KIND_TAG: { + const struct btf_tag *tag = (const void *)(t + 1); + + if (json_output) { + jsonw_uint_field(w, "type_id", t->type); + jsonw_int_field(w, "component_idx", tag->component_idx); + } else { + printf(" type_id=%u component_idx=%d", t->type, tag->component_idx); + } + break; + } default: break; } From 71d29c2d47d112404fe23e31cf33f7cccde75a8c Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Tue, 14 Sep 2021 15:30:36 -0700 Subject: [PATCH 06/11] selftests/bpf: Test libbpf API function btf__add_tag() Add btf_write tests with btf__add_tag() function. Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210914223036.247560-1-yhs@fb.com --- tools/testing/selftests/bpf/btf_helpers.c | 7 ++++++- .../selftests/bpf/prog_tests/btf_write.c | 21 +++++++++++++++++++ 2 files changed, 27 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/btf_helpers.c b/tools/testing/selftests/bpf/btf_helpers.c index b692e6ead9b5..ce103fb0ad1b 100644 --- a/tools/testing/selftests/bpf/btf_helpers.c +++ b/tools/testing/selftests/bpf/btf_helpers.c @@ -24,11 +24,12 @@ static const char * const btf_kind_str_mapping[] = { [BTF_KIND_VAR] = "VAR", [BTF_KIND_DATASEC] = "DATASEC", [BTF_KIND_FLOAT] = "FLOAT", + [BTF_KIND_TAG] = "TAG", }; static const char *btf_kind_str(__u16 kind) { - if (kind > BTF_KIND_DATASEC) + if (kind > BTF_KIND_TAG) return "UNKNOWN"; return btf_kind_str_mapping[kind]; } @@ -177,6 +178,10 @@ int fprintf_btf_type_raw(FILE *out, const struct btf *btf, __u32 id) case BTF_KIND_FLOAT: fprintf(out, " size=%u", t->size); break; + case BTF_KIND_TAG: + fprintf(out, " type_id=%u component_idx=%d", + t->type, btf_tag(t)->component_idx); + break; default: break; } diff --git a/tools/testing/selftests/bpf/prog_tests/btf_write.c b/tools/testing/selftests/bpf/prog_tests/btf_write.c index 022c7d89d6f4..76548eecce2c 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf_write.c +++ b/tools/testing/selftests/bpf/prog_tests/btf_write.c @@ -281,5 +281,26 @@ void test_btf_write() { "[17] DATASEC 'datasec1' size=12 vlen=1\n" "\ttype_id=1 offset=4 size=8", "raw_dump"); + /* TAG */ + id = btf__add_tag(btf, "tag1", 16, -1); + ASSERT_EQ(id, 18, "tag_id"); + t = btf__type_by_id(btf, 18); + ASSERT_STREQ(btf__str_by_offset(btf, t->name_off), "tag1", "tag_value"); + ASSERT_EQ(btf_kind(t), BTF_KIND_TAG, "tag_kind"); + ASSERT_EQ(t->type, 16, "tag_type"); + ASSERT_EQ(btf_tag(t)->component_idx, -1, "tag_component_idx"); + ASSERT_STREQ(btf_type_raw_dump(btf, 18), + "[18] TAG 'tag1' type_id=16 component_idx=-1", "raw_dump"); + + id = btf__add_tag(btf, "tag2", 14, 1); + ASSERT_EQ(id, 19, "tag_id"); + t = btf__type_by_id(btf, 19); + ASSERT_STREQ(btf__str_by_offset(btf, t->name_off), "tag2", "tag_value"); + ASSERT_EQ(btf_kind(t), BTF_KIND_TAG, "tag_kind"); + ASSERT_EQ(t->type, 14, "tag_type"); + ASSERT_EQ(btf_tag(t)->component_idx, 1, "tag_component_idx"); + ASSERT_STREQ(btf_type_raw_dump(btf, 19), + "[19] TAG 'tag2' type_id=14 component_idx=1", "raw_dump"); + btf__free(btf); } From 3df3bd68d4811bccc74adc04d4d84512957a1a07 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Tue, 14 Sep 2021 15:30:41 -0700 Subject: [PATCH 07/11] selftests/bpf: Change NAME_NTH/IS_NAME_NTH for BTF_KIND_TAG format BTF_KIND_TAG ELF format has a component_idx which might have value -1. test_btf may confuse it with common_type.name as NAME_NTH checkes high 16bit to be 0xffff. Change NAME_NTH high 16bit check to be 0xfffe so it won't confuse with component_idx. Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210914223041.248009-1-yhs@fb.com --- tools/testing/selftests/bpf/prog_tests/btf.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/btf.c b/tools/testing/selftests/bpf/prog_tests/btf.c index 649f87382c8d..ad39f4d588d0 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf.c +++ b/tools/testing/selftests/bpf/prog_tests/btf.c @@ -39,8 +39,8 @@ static bool always_log; #define BTF_END_RAW 0xdeadbeef #define NAME_TBD 0xdeadb33f -#define NAME_NTH(N) (0xffff0000 | N) -#define IS_NAME_NTH(X) ((X & 0xffff0000) == 0xffff0000) +#define NAME_NTH(N) (0xfffe0000 | N) +#define IS_NAME_NTH(X) ((X & 0xffff0000) == 0xfffe0000) #define GET_NAME_NTH_IDX(X) (X & 0x0000ffff) #define MAX_NR_RAW_U32 1024 From 35baba7a832fa466b4aa2e0d00473d795cec8f20 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Tue, 14 Sep 2021 15:30:47 -0700 Subject: [PATCH 08/11] selftests/bpf: Add BTF_KIND_TAG unit tests Test good and bad variants of BTF_KIND_TAG encoding. Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210914223047.248223-1-yhs@fb.com --- tools/testing/selftests/bpf/prog_tests/btf.c | 245 +++++++++++++++++++ tools/testing/selftests/bpf/test_btf.h | 3 + 2 files changed, 248 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/btf.c b/tools/testing/selftests/bpf/prog_tests/btf.c index ad39f4d588d0..b4e86a8423cb 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf.c +++ b/tools/testing/selftests/bpf/prog_tests/btf.c @@ -3661,6 +3661,249 @@ static struct btf_raw_test raw_tests[] = { .err_str = "Invalid type_size", }, +{ + .descr = "tag test #1, struct/member, well-formed", + .raw_types = { + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + BTF_STRUCT_ENC(0, 2, 8), /* [2] */ + BTF_MEMBER_ENC(NAME_TBD, 1, 0), + BTF_MEMBER_ENC(NAME_TBD, 1, 32), + BTF_TAG_ENC(NAME_TBD, 2, -1), + BTF_TAG_ENC(NAME_TBD, 2, 0), + BTF_TAG_ENC(NAME_TBD, 2, 1), + BTF_END_RAW, + }, + BTF_STR_SEC("\0m1\0m2\0tag1\0tag2\0tag3"), + .map_type = BPF_MAP_TYPE_ARRAY, + .map_name = "tag_type_check_btf", + .key_size = sizeof(int), + .value_size = 8, + .key_type_id = 1, + .value_type_id = 2, + .max_entries = 1, +}, +{ + .descr = "tag test #2, union/member, well-formed", + .raw_types = { + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + BTF_UNION_ENC(NAME_TBD, 2, 4), /* [2] */ + BTF_MEMBER_ENC(NAME_TBD, 1, 0), + BTF_MEMBER_ENC(NAME_TBD, 1, 0), + BTF_TAG_ENC(NAME_TBD, 2, -1), + BTF_TAG_ENC(NAME_TBD, 2, 0), + BTF_TAG_ENC(NAME_TBD, 2, 1), + BTF_END_RAW, + }, + BTF_STR_SEC("\0t\0m1\0m2\0tag1\0tag2\0tag3"), + .map_type = BPF_MAP_TYPE_ARRAY, + .map_name = "tag_type_check_btf", + .key_size = sizeof(int), + .value_size = 4, + .key_type_id = 1, + .value_type_id = 2, + .max_entries = 1, +}, +{ + .descr = "tag test #3, variable, well-formed", + .raw_types = { + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + BTF_VAR_ENC(NAME_TBD, 1, 0), /* [2] */ + BTF_VAR_ENC(NAME_TBD, 1, 1), /* [3] */ + BTF_TAG_ENC(NAME_TBD, 2, -1), + BTF_TAG_ENC(NAME_TBD, 3, -1), + BTF_END_RAW, + }, + BTF_STR_SEC("\0local\0global\0tag1\0tag2"), + .map_type = BPF_MAP_TYPE_ARRAY, + .map_name = "tag_type_check_btf", + .key_size = sizeof(int), + .value_size = 4, + .key_type_id = 1, + .value_type_id = 1, + .max_entries = 1, +}, +{ + .descr = "tag test #4, func/parameter, well-formed", + .raw_types = { + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + BTF_FUNC_PROTO_ENC(0, 2), /* [2] */ + BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 1), + BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 1), + BTF_FUNC_ENC(NAME_TBD, 2), /* [3] */ + BTF_TAG_ENC(NAME_TBD, 3, -1), + BTF_TAG_ENC(NAME_TBD, 3, 0), + BTF_TAG_ENC(NAME_TBD, 3, 1), + BTF_END_RAW, + }, + BTF_STR_SEC("\0arg1\0arg2\0f\0tag1\0tag2\0tag3"), + .map_type = BPF_MAP_TYPE_ARRAY, + .map_name = "tag_type_check_btf", + .key_size = sizeof(int), + .value_size = 4, + .key_type_id = 1, + .value_type_id = 1, + .max_entries = 1, +}, +{ + .descr = "tag test #5, invalid value", + .raw_types = { + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + BTF_VAR_ENC(NAME_TBD, 1, 0), /* [2] */ + BTF_TAG_ENC(0, 2, -1), + BTF_END_RAW, + }, + BTF_STR_SEC("\0local\0tag"), + .map_type = BPF_MAP_TYPE_ARRAY, + .map_name = "tag_type_check_btf", + .key_size = sizeof(int), + .value_size = 4, + .key_type_id = 1, + .value_type_id = 1, + .max_entries = 1, + .btf_load_err = true, + .err_str = "Invalid value", +}, +{ + .descr = "tag test #6, invalid target type", + .raw_types = { + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + BTF_TAG_ENC(NAME_TBD, 1, -1), + BTF_END_RAW, + }, + BTF_STR_SEC("\0tag1"), + .map_type = BPF_MAP_TYPE_ARRAY, + .map_name = "tag_type_check_btf", + .key_size = sizeof(int), + .value_size = 4, + .key_type_id = 1, + .value_type_id = 1, + .max_entries = 1, + .btf_load_err = true, + .err_str = "Invalid type", +}, +{ + .descr = "tag test #7, invalid vlen", + .raw_types = { + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + BTF_VAR_ENC(NAME_TBD, 1, 0), /* [2] */ + BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_TAG, 0, 1), 2), (0), + BTF_END_RAW, + }, + BTF_STR_SEC("\0local\0tag1"), + .map_type = BPF_MAP_TYPE_ARRAY, + .map_name = "tag_type_check_btf", + .key_size = sizeof(int), + .value_size = 4, + .key_type_id = 1, + .value_type_id = 1, + .max_entries = 1, + .btf_load_err = true, + .err_str = "vlen != 0", +}, +{ + .descr = "tag test #8, invalid kflag", + .raw_types = { + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + BTF_VAR_ENC(NAME_TBD, 1, 0), /* [2] */ + BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_TAG, 1, 0), 2), (-1), + BTF_END_RAW, + }, + BTF_STR_SEC("\0local\0tag1"), + .map_type = BPF_MAP_TYPE_ARRAY, + .map_name = "tag_type_check_btf", + .key_size = sizeof(int), + .value_size = 4, + .key_type_id = 1, + .value_type_id = 1, + .max_entries = 1, + .btf_load_err = true, + .err_str = "Invalid btf_info kind_flag", +}, +{ + .descr = "tag test #9, var, invalid component_idx", + .raw_types = { + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + BTF_VAR_ENC(NAME_TBD, 1, 0), /* [2] */ + BTF_TAG_ENC(NAME_TBD, 2, 0), + BTF_END_RAW, + }, + BTF_STR_SEC("\0local\0tag"), + .map_type = BPF_MAP_TYPE_ARRAY, + .map_name = "tag_type_check_btf", + .key_size = sizeof(int), + .value_size = 4, + .key_type_id = 1, + .value_type_id = 1, + .max_entries = 1, + .btf_load_err = true, + .err_str = "Invalid component_idx", +}, +{ + .descr = "tag test #10, struct member, invalid component_idx", + .raw_types = { + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + BTF_STRUCT_ENC(0, 2, 8), /* [2] */ + BTF_MEMBER_ENC(NAME_TBD, 1, 0), + BTF_MEMBER_ENC(NAME_TBD, 1, 32), + BTF_TAG_ENC(NAME_TBD, 2, 2), + BTF_END_RAW, + }, + BTF_STR_SEC("\0m1\0m2\0tag"), + .map_type = BPF_MAP_TYPE_ARRAY, + .map_name = "tag_type_check_btf", + .key_size = sizeof(int), + .value_size = 8, + .key_type_id = 1, + .value_type_id = 2, + .max_entries = 1, + .btf_load_err = true, + .err_str = "Invalid component_idx", +}, +{ + .descr = "tag test #11, func parameter, invalid component_idx", + .raw_types = { + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + BTF_FUNC_PROTO_ENC(0, 2), /* [2] */ + BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 1), + BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 1), + BTF_FUNC_ENC(NAME_TBD, 2), /* [3] */ + BTF_TAG_ENC(NAME_TBD, 3, 2), + BTF_END_RAW, + }, + BTF_STR_SEC("\0arg1\0arg2\0f\0tag"), + .map_type = BPF_MAP_TYPE_ARRAY, + .map_name = "tag_type_check_btf", + .key_size = sizeof(int), + .value_size = 4, + .key_type_id = 1, + .value_type_id = 1, + .max_entries = 1, + .btf_load_err = true, + .err_str = "Invalid component_idx", +}, +{ + .descr = "tag test #12, < -1 component_idx", + .raw_types = { + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + BTF_FUNC_PROTO_ENC(0, 2), /* [2] */ + BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 1), + BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 1), + BTF_FUNC_ENC(NAME_TBD, 2), /* [3] */ + BTF_TAG_ENC(NAME_TBD, 3, -2), + BTF_END_RAW, + }, + BTF_STR_SEC("\0arg1\0arg2\0f\0tag"), + .map_type = BPF_MAP_TYPE_ARRAY, + .map_name = "tag_type_check_btf", + .key_size = sizeof(int), + .value_size = 4, + .key_type_id = 1, + .value_type_id = 1, + .max_entries = 1, + .btf_load_err = true, + .err_str = "Invalid component_idx", +}, + }; /* struct btf_raw_test raw_tests[] */ static const char *get_next_str(const char *start, const char *end) @@ -6801,6 +7044,8 @@ static int btf_type_size(const struct btf_type *t) return base_size + sizeof(struct btf_var); case BTF_KIND_DATASEC: return base_size + vlen * sizeof(struct btf_var_secinfo); + case BTF_KIND_TAG: + return base_size + sizeof(struct btf_tag); default: fprintf(stderr, "Unsupported BTF_KIND:%u\n", kind); return -EINVAL; diff --git a/tools/testing/selftests/bpf/test_btf.h b/tools/testing/selftests/bpf/test_btf.h index e2394eea4b7f..0619e06d745e 100644 --- a/tools/testing/selftests/bpf/test_btf.h +++ b/tools/testing/selftests/bpf/test_btf.h @@ -69,4 +69,7 @@ #define BTF_TYPE_FLOAT_ENC(name, sz) \ BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz) +#define BTF_TAG_ENC(value, type, component_idx) \ + BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_TAG, 0, 0), type), (component_idx) + #endif /* _TEST_BTF_H */ From ad526474aec1d9abb9838e3fb1330bb991715c22 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Tue, 14 Sep 2021 15:30:52 -0700 Subject: [PATCH 09/11] selftests/bpf: Test BTF_KIND_TAG for deduplication Add unit tests for BTF_KIND_TAG deduplication for - struct and struct member - variable - func and func argument Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210914223052.248535-1-yhs@fb.com --- tools/testing/selftests/bpf/prog_tests/btf.c | 192 +++++++++++++++++-- 1 file changed, 175 insertions(+), 17 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/btf.c b/tools/testing/selftests/bpf/prog_tests/btf.c index b4e86a8423cb..9c85d7d27409 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf.c +++ b/tools/testing/selftests/bpf/prog_tests/btf.c @@ -6664,27 +6664,33 @@ const struct btf_dedup_test dedup_tests[] = { BTF_MEMBER_ENC(NAME_NTH(4), 5, 64), /* const int *a; */ BTF_MEMBER_ENC(NAME_NTH(5), 2, 128), /* int b[16]; */ BTF_MEMBER_ENC(NAME_NTH(6), 1, 640), /* int c; */ - BTF_MEMBER_ENC(NAME_NTH(8), 13, 672), /* float d; */ + BTF_MEMBER_ENC(NAME_NTH(8), 15, 672), /* float d; */ /* ptr -> [3] struct s */ BTF_PTR_ENC(3), /* [4] */ /* ptr -> [6] const int */ BTF_PTR_ENC(6), /* [5] */ /* const -> [1] int */ BTF_CONST_ENC(1), /* [6] */ + /* tag -> [3] struct s */ + BTF_TAG_ENC(NAME_NTH(2), 3, -1), /* [7] */ + /* tag -> [3] struct s, member 1 */ + BTF_TAG_ENC(NAME_NTH(2), 3, 1), /* [8] */ /* full copy of the above */ - BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 32, 4), /* [7] */ - BTF_TYPE_ARRAY_ENC(7, 7, 16), /* [8] */ - BTF_STRUCT_ENC(NAME_NTH(2), 5, 88), /* [9] */ - BTF_MEMBER_ENC(NAME_NTH(3), 10, 0), - BTF_MEMBER_ENC(NAME_NTH(4), 11, 64), - BTF_MEMBER_ENC(NAME_NTH(5), 8, 128), - BTF_MEMBER_ENC(NAME_NTH(6), 7, 640), - BTF_MEMBER_ENC(NAME_NTH(8), 13, 672), - BTF_PTR_ENC(9), /* [10] */ - BTF_PTR_ENC(12), /* [11] */ - BTF_CONST_ENC(7), /* [12] */ - BTF_TYPE_FLOAT_ENC(NAME_NTH(7), 4), /* [13] */ + BTF_TYPE_INT_ENC(NAME_NTH(1), BTF_INT_SIGNED, 0, 32, 4), /* [9] */ + BTF_TYPE_ARRAY_ENC(9, 9, 16), /* [10] */ + BTF_STRUCT_ENC(NAME_NTH(2), 5, 88), /* [11] */ + BTF_MEMBER_ENC(NAME_NTH(3), 12, 0), + BTF_MEMBER_ENC(NAME_NTH(4), 13, 64), + BTF_MEMBER_ENC(NAME_NTH(5), 10, 128), + BTF_MEMBER_ENC(NAME_NTH(6), 9, 640), + BTF_MEMBER_ENC(NAME_NTH(8), 15, 672), + BTF_PTR_ENC(11), /* [12] */ + BTF_PTR_ENC(14), /* [13] */ + BTF_CONST_ENC(9), /* [14] */ + BTF_TYPE_FLOAT_ENC(NAME_NTH(7), 4), /* [15] */ + BTF_TAG_ENC(NAME_NTH(2), 11, -1), /* [16] */ + BTF_TAG_ENC(NAME_NTH(2), 11, 1), /* [17] */ BTF_END_RAW, }, BTF_STR_SEC("\0int\0s\0next\0a\0b\0c\0float\0d"), @@ -6701,14 +6707,16 @@ const struct btf_dedup_test dedup_tests[] = { BTF_MEMBER_ENC(NAME_NTH(1), 5, 64), /* const int *a; */ BTF_MEMBER_ENC(NAME_NTH(2), 2, 128), /* int b[16]; */ BTF_MEMBER_ENC(NAME_NTH(3), 1, 640), /* int c; */ - BTF_MEMBER_ENC(NAME_NTH(4), 7, 672), /* float d; */ + BTF_MEMBER_ENC(NAME_NTH(4), 9, 672), /* float d; */ /* ptr -> [3] struct s */ BTF_PTR_ENC(3), /* [4] */ /* ptr -> [6] const int */ BTF_PTR_ENC(6), /* [5] */ /* const -> [1] int */ BTF_CONST_ENC(1), /* [6] */ - BTF_TYPE_FLOAT_ENC(NAME_NTH(7), 4), /* [7] */ + BTF_TAG_ENC(NAME_NTH(2), 3, -1), /* [7] */ + BTF_TAG_ENC(NAME_NTH(2), 3, 1), /* [8] */ + BTF_TYPE_FLOAT_ENC(NAME_NTH(7), 4), /* [9] */ BTF_END_RAW, }, BTF_STR_SEC("\0a\0b\0c\0d\0int\0float\0next\0s"), @@ -6833,9 +6841,11 @@ const struct btf_dedup_test dedup_tests[] = { BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 8), BTF_FUNC_ENC(NAME_TBD, 12), /* [13] func */ BTF_TYPE_FLOAT_ENC(NAME_TBD, 2), /* [14] float */ + BTF_TAG_ENC(NAME_TBD, 13, -1), /* [15] tag */ + BTF_TAG_ENC(NAME_TBD, 13, 1), /* [16] tag */ BTF_END_RAW, }, - BTF_STR_SEC("\0A\0B\0C\0D\0E\0F\0G\0H\0I\0J\0K\0L\0M\0N"), + BTF_STR_SEC("\0A\0B\0C\0D\0E\0F\0G\0H\0I\0J\0K\0L\0M\0N\0O\0P"), }, .expect = { .raw_types = { @@ -6859,9 +6869,11 @@ const struct btf_dedup_test dedup_tests[] = { BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 8), BTF_FUNC_ENC(NAME_TBD, 12), /* [13] func */ BTF_TYPE_FLOAT_ENC(NAME_TBD, 2), /* [14] float */ + BTF_TAG_ENC(NAME_TBD, 13, -1), /* [15] tag */ + BTF_TAG_ENC(NAME_TBD, 13, 1), /* [16] tag */ BTF_END_RAW, }, - BTF_STR_SEC("\0A\0B\0C\0D\0E\0F\0G\0H\0I\0J\0K\0L\0M\0N"), + BTF_STR_SEC("\0A\0B\0C\0D\0E\0F\0G\0H\0I\0J\0K\0L\0M\0N\0O\0P"), }, .opts = { .dont_resolve_fwds = false, @@ -7010,6 +7022,152 @@ const struct btf_dedup_test dedup_tests[] = { .dedup_table_size = 1 }, }, +{ + .descr = "dedup: func/func_arg/var tags", + .input = { + .raw_types = { + /* int */ + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + /* static int t */ + BTF_VAR_ENC(NAME_NTH(1), 1, 0), /* [2] */ + /* void f(int a1, int a2) */ + BTF_FUNC_PROTO_ENC(0, 2), /* [3] */ + BTF_FUNC_PROTO_ARG_ENC(NAME_NTH(2), 1), + BTF_FUNC_PROTO_ARG_ENC(NAME_NTH(3), 1), + BTF_FUNC_ENC(NAME_NTH(4), 2), /* [4] */ + /* tag -> t */ + BTF_TAG_ENC(NAME_NTH(5), 2, -1), /* [5] */ + BTF_TAG_ENC(NAME_NTH(5), 2, -1), /* [6] */ + /* tag -> func */ + BTF_TAG_ENC(NAME_NTH(5), 4, -1), /* [7] */ + BTF_TAG_ENC(NAME_NTH(5), 4, -1), /* [8] */ + /* tag -> func arg a1 */ + BTF_TAG_ENC(NAME_NTH(5), 4, 1), /* [9] */ + BTF_TAG_ENC(NAME_NTH(5), 4, 1), /* [10] */ + BTF_END_RAW, + }, + BTF_STR_SEC("\0t\0a1\0a2\0f\0tag"), + }, + .expect = { + .raw_types = { + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + BTF_VAR_ENC(NAME_NTH(1), 1, 0), /* [2] */ + BTF_FUNC_PROTO_ENC(0, 2), /* [3] */ + BTF_FUNC_PROTO_ARG_ENC(NAME_NTH(2), 1), + BTF_FUNC_PROTO_ARG_ENC(NAME_NTH(3), 1), + BTF_FUNC_ENC(NAME_NTH(4), 2), /* [4] */ + BTF_TAG_ENC(NAME_NTH(5), 2, -1), /* [5] */ + BTF_TAG_ENC(NAME_NTH(5), 4, -1), /* [6] */ + BTF_TAG_ENC(NAME_NTH(5), 4, 1), /* [7] */ + BTF_END_RAW, + }, + BTF_STR_SEC("\0t\0a1\0a2\0f\0tag"), + }, + .opts = { + .dont_resolve_fwds = false, + }, +}, +{ + .descr = "dedup: func/func_param tags", + .input = { + .raw_types = { + /* int */ + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + /* void f(int a1, int a2) */ + BTF_FUNC_PROTO_ENC(0, 2), /* [2] */ + BTF_FUNC_PROTO_ARG_ENC(NAME_NTH(1), 1), + BTF_FUNC_PROTO_ARG_ENC(NAME_NTH(2), 1), + BTF_FUNC_ENC(NAME_NTH(3), 2), /* [3] */ + /* void f(int a1, int a2) */ + BTF_FUNC_PROTO_ENC(0, 2), /* [4] */ + BTF_FUNC_PROTO_ARG_ENC(NAME_NTH(1), 1), + BTF_FUNC_PROTO_ARG_ENC(NAME_NTH(2), 1), + BTF_FUNC_ENC(NAME_NTH(3), 4), /* [5] */ + /* tag -> f: tag1, tag2 */ + BTF_TAG_ENC(NAME_NTH(4), 3, -1), /* [6] */ + BTF_TAG_ENC(NAME_NTH(5), 3, -1), /* [7] */ + /* tag -> f/a2: tag1, tag2 */ + BTF_TAG_ENC(NAME_NTH(4), 3, 1), /* [8] */ + BTF_TAG_ENC(NAME_NTH(5), 3, 1), /* [9] */ + /* tag -> f: tag1, tag3 */ + BTF_TAG_ENC(NAME_NTH(4), 5, -1), /* [10] */ + BTF_TAG_ENC(NAME_NTH(6), 5, -1), /* [11] */ + /* tag -> f/a2: tag1, tag3 */ + BTF_TAG_ENC(NAME_NTH(4), 5, 1), /* [12] */ + BTF_TAG_ENC(NAME_NTH(6), 5, 1), /* [13] */ + BTF_END_RAW, + }, + BTF_STR_SEC("\0a1\0a2\0f\0tag1\0tag2\0tag3"), + }, + .expect = { + .raw_types = { + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + BTF_FUNC_PROTO_ENC(0, 2), /* [2] */ + BTF_FUNC_PROTO_ARG_ENC(NAME_NTH(1), 1), + BTF_FUNC_PROTO_ARG_ENC(NAME_NTH(2), 1), + BTF_FUNC_ENC(NAME_NTH(3), 2), /* [3] */ + BTF_TAG_ENC(NAME_NTH(4), 3, -1), /* [4] */ + BTF_TAG_ENC(NAME_NTH(5), 3, -1), /* [5] */ + BTF_TAG_ENC(NAME_NTH(6), 3, -1), /* [6] */ + BTF_TAG_ENC(NAME_NTH(4), 3, 1), /* [7] */ + BTF_TAG_ENC(NAME_NTH(5), 3, 1), /* [8] */ + BTF_TAG_ENC(NAME_NTH(6), 3, 1), /* [9] */ + BTF_END_RAW, + }, + BTF_STR_SEC("\0a1\0a2\0f\0tag1\0tag2\0tag3"), + }, + .opts = { + .dont_resolve_fwds = false, + }, +}, +{ + .descr = "dedup: struct/struct_member tags", + .input = { + .raw_types = { + /* int */ + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + BTF_STRUCT_ENC(NAME_NTH(1), 2, 8), /* [2] */ + BTF_MEMBER_ENC(NAME_NTH(2), 1, 0), + BTF_MEMBER_ENC(NAME_NTH(3), 1, 32), + BTF_STRUCT_ENC(NAME_NTH(1), 2, 8), /* [3] */ + BTF_MEMBER_ENC(NAME_NTH(2), 1, 0), + BTF_MEMBER_ENC(NAME_NTH(3), 1, 32), + /* tag -> t: tag1, tag2 */ + BTF_TAG_ENC(NAME_NTH(4), 2, -1), /* [4] */ + BTF_TAG_ENC(NAME_NTH(5), 2, -1), /* [5] */ + /* tag -> t/m2: tag1, tag2 */ + BTF_TAG_ENC(NAME_NTH(4), 2, 1), /* [6] */ + BTF_TAG_ENC(NAME_NTH(5), 2, 1), /* [7] */ + /* tag -> t: tag1, tag3 */ + BTF_TAG_ENC(NAME_NTH(4), 3, -1), /* [8] */ + BTF_TAG_ENC(NAME_NTH(6), 3, -1), /* [9] */ + /* tag -> t/m2: tag1, tag3 */ + BTF_TAG_ENC(NAME_NTH(4), 3, 1), /* [10] */ + BTF_TAG_ENC(NAME_NTH(6), 3, 1), /* [11] */ + BTF_END_RAW, + }, + BTF_STR_SEC("\0t\0m1\0m2\0tag1\0tag2\0tag3"), + }, + .expect = { + .raw_types = { + BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ + BTF_STRUCT_ENC(NAME_NTH(1), 2, 8), /* [2] */ + BTF_MEMBER_ENC(NAME_NTH(2), 1, 0), + BTF_MEMBER_ENC(NAME_NTH(3), 1, 32), + BTF_TAG_ENC(NAME_NTH(4), 2, -1), /* [3] */ + BTF_TAG_ENC(NAME_NTH(5), 2, -1), /* [4] */ + BTF_TAG_ENC(NAME_NTH(6), 2, -1), /* [5] */ + BTF_TAG_ENC(NAME_NTH(4), 2, 1), /* [6] */ + BTF_TAG_ENC(NAME_NTH(5), 2, 1), /* [7] */ + BTF_TAG_ENC(NAME_NTH(6), 2, 1), /* [8] */ + BTF_END_RAW, + }, + BTF_STR_SEC("\0t\0m1\0m2\0tag1\0tag2\0tag3"), + }, + .opts = { + .dont_resolve_fwds = false, + }, +}, }; From c240ba28789063690077d282f8f89e03f31037d0 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Tue, 14 Sep 2021 15:30:58 -0700 Subject: [PATCH 10/11] selftests/bpf: Add a test with a bpf program with btf_tag attributes Add a bpf program with btf_tag attributes. The program is loaded successfully with the kernel. With the command bpftool btf dump file ./tag.o the following dump shows that tags are properly encoded: [8] STRUCT 'key_t' size=12 vlen=3 'a' type_id=2 bits_offset=0 'b' type_id=2 bits_offset=32 'c' type_id=2 bits_offset=64 [9] TAG 'tag1' type_id=8 component_id=-1 [10] TAG 'tag2' type_id=8 component_id=-1 [11] TAG 'tag1' type_id=8 component_id=1 [12] TAG 'tag2' type_id=8 component_id=1 ... [21] FUNC_PROTO '(anon)' ret_type_id=2 vlen=1 'x' type_id=2 [22] FUNC 'foo' type_id=21 linkage=static [23] TAG 'tag1' type_id=22 component_id=0 [24] TAG 'tag2' type_id=22 component_id=0 [25] TAG 'tag1' type_id=22 component_id=-1 [26] TAG 'tag2' type_id=22 component_id=-1 ... [29] VAR 'total' type_id=27, linkage=global [30] TAG 'tag1' type_id=29 component_id=-1 [31] TAG 'tag2' type_id=29 component_id=-1 If an old clang compiler, which does not support btf_tag attribute, is used, these btf_tag attributes will be silently ignored. Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210914223058.248949-1-yhs@fb.com --- .../selftests/bpf/prog_tests/btf_tag.c | 14 +++++++ tools/testing/selftests/bpf/progs/tag.c | 39 +++++++++++++++++++ 2 files changed, 53 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/btf_tag.c create mode 100644 tools/testing/selftests/bpf/progs/tag.c diff --git a/tools/testing/selftests/bpf/prog_tests/btf_tag.c b/tools/testing/selftests/bpf/prog_tests/btf_tag.c new file mode 100644 index 000000000000..f939527ede77 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/btf_tag.c @@ -0,0 +1,14 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ +#include +#include "tag.skel.h" + +void test_btf_tag(void) +{ + struct tag *skel; + + skel = tag__open_and_load(); + if (!ASSERT_OK_PTR(skel, "btf_tag")) + return; + tag__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/tag.c b/tools/testing/selftests/bpf/progs/tag.c new file mode 100644 index 000000000000..17f88c58a6c5 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/tag.c @@ -0,0 +1,39 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ +#include "vmlinux.h" +#include +#include + +#define __tag1 __attribute__((btf_tag("tag1"))) +#define __tag2 __attribute__((btf_tag("tag2"))) + +struct key_t { + int a; + int b __tag1 __tag2; + int c; +} __tag1 __tag2; + +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(max_entries, 3); + __type(key, struct key_t); + __type(value, __u64); +} hashmap1 SEC(".maps"); + +__u32 total __tag1 __tag2 = 0; + +static __noinline int foo(int x __tag1 __tag2) __tag1 __tag2 +{ + struct key_t key; + __u64 val = 1; + + key.a = key.b = key.c = x; + bpf_map_update_elem(&hashmap1, &key, &val, 0); + return 0; +} + +SEC("fentry/bpf_fentry_test1") +int BPF_PROG(sub, int x) +{ + return foo(x); +} From 48f5a6c4162706f94523d7a0d828e4aee77d17e7 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Tue, 14 Sep 2021 15:31:03 -0700 Subject: [PATCH 11/11] docs/bpf: Add documentation for BTF_KIND_TAG Add BTF_KIND_TAG documentation in btf.rst. Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210914223103.249100-1-yhs@fb.com --- Documentation/bpf/btf.rst | 29 ++++++++++++++++++++++++++++- 1 file changed, 28 insertions(+), 1 deletion(-) diff --git a/Documentation/bpf/btf.rst b/Documentation/bpf/btf.rst index 846354cd2d69..1bfe4072f5fc 100644 --- a/Documentation/bpf/btf.rst +++ b/Documentation/bpf/btf.rst @@ -85,6 +85,7 @@ sequentially and type id is assigned to each recognized type starting from id #define BTF_KIND_VAR 14 /* Variable */ #define BTF_KIND_DATASEC 15 /* Section */ #define BTF_KIND_FLOAT 16 /* Floating point */ + #define BTF_KIND_TAG 17 /* Tag */ Note that the type section encodes debug info, not just pure types. ``BTF_KIND_FUNC`` is not a type, and it represents a defined subprogram. @@ -106,7 +107,7 @@ Each type contains the following common data:: * "size" tells the size of the type it is describing. * * "type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT, - * FUNC and FUNC_PROTO. + * FUNC, FUNC_PROTO and TAG. * "type" is a type_id referring to another type. */ union { @@ -465,6 +466,32 @@ map definition. No additional type data follow ``btf_type``. +2.2.17 BTF_KIND_TAG +~~~~~~~~~~~~~~~~~~~ + +``struct btf_type`` encoding requirement: + * ``name_off``: offset to a non-empty string + * ``info.kind_flag``: 0 + * ``info.kind``: BTF_KIND_TAG + * ``info.vlen``: 0 + * ``type``: ``struct``, ``union``, ``func`` or ``var`` + +``btf_type`` is followed by ``struct btf_tag``.:: + + struct btf_tag { + __u32 component_idx; + }; + +The ``name_off`` encodes btf_tag attribute string. +The ``type`` should be ``struct``, ``union``, ``func`` or ``var``. +For ``var`` type, ``btf_tag.component_idx`` must be ``-1``. +For the other three types, if the btf_tag attribute is +applied to the ``struct``, ``union`` or ``func`` itself, +``btf_tag.component_idx`` must be ``-1``. Otherwise, +the attribute is applied to a ``struct``/``union`` member or +a ``func`` argument, and ``btf_tag.component_idx`` should be a +valid index (starting from 0) pointing to a member or an argument. + 3. BTF Kernel API *****************