From 764d19da07f0cd1f40efd468bef87fb3b9f90e98 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 6 Jun 2024 14:26:07 -0700 Subject: [PATCH 01/26] ci: revert switching to ubuntu-latest for pahole-staging workflow pahole staging workflow is using the same old VM image as BPF selftests stages. It doesn't have recent enough glibc, so we can't yet switch to newer Ubuntu, unfortunately. Signed-off-by: Andrii Nakryiko --- .github/workflows/pahole.yml | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/.github/workflows/pahole.yml b/.github/workflows/pahole.yml index e666fb6..930832e 100644 --- a/.github/workflows/pahole.yml +++ b/.github/workflows/pahole.yml @@ -7,7 +7,7 @@ on: jobs: vmtest: - runs-on: ubuntu-latest + runs-on: ubuntu-20.04 name: Kernel LATEST + staging pahole env: STAGING: tmp.master From 42065ea6627ff6e1ab4c65e51042a70fbf30ff7c Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 6 Jun 2024 14:34:50 -0700 Subject: [PATCH 02/26] ci: make pahole-staging workflow manually triggerable Allow to manually trigger pahole-staging workflow. Signed-off-by: Andrii Nakryiko --- .github/workflows/pahole.yml | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/.github/workflows/pahole.yml b/.github/workflows/pahole.yml index 930832e..3034dda 100644 --- a/.github/workflows/pahole.yml +++ b/.github/workflows/pahole.yml @@ -1,10 +1,10 @@ name: pahole-staging on: + workflow_dispatch: schedule: - cron: '0 18 * * *' - jobs: vmtest: runs-on: ubuntu-20.04 From cece3242fb2aa7824507ff4aa7dd3b2ab956050a Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 4 Jun 2024 17:16:25 -0700 Subject: [PATCH 03/26] libbpf: Add BTF field iterator Implement iterator-based type ID and string offset BTF field iterator. This is used extensively in BTF-handling code and BPF linker code for various sanity checks, rewriting IDs/offsets, etc. Currently this is implemented as visitor pattern calling custom callbacks, which makes the logic (especially in simple cases) unnecessarily obscure and harder to follow. Having equivalent functionality using iterator pattern makes for simpler to understand and maintain code. As we add more code for BTF processing logic in libbpf, it's best to switch to iterator pattern before adding more callback-based code. The idea for iterator-based implementation is to record offsets of necessary fields within fixed btf_type parts (which should be iterated just once), and, for kinds that have multiple members (based on vlen field), record where in each member necessary fields are located. Generic iteration code then just keeps track of last offset that was returned and handles N members correctly. Return type is just u32 pointer, where NULL is returned when all relevant fields were already iterated. Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Tested-by: Alan Maguire Acked-by: Eduard Zingerman Acked-by: Jiri Olsa Link: https://lore.kernel.org/bpf/20240605001629.4061937-2-andrii@kernel.org --- src/btf.c | 162 ++++++++++++++++++++++++++++++++++++++++++ src/libbpf_internal.h | 24 +++++++ 2 files changed, 186 insertions(+) diff --git a/src/btf.c b/src/btf.c index 2d0840e..50ff8b6 100644 --- a/src/btf.c +++ b/src/btf.c @@ -5133,6 +5133,168 @@ int btf_type_visit_str_offs(struct btf_type *t, str_off_visit_fn visit, void *ct return 0; } +int btf_field_iter_init(struct btf_field_iter *it, struct btf_type *t, enum btf_field_iter_kind iter_kind) +{ + it->p = NULL; + it->m_idx = -1; + it->off_idx = 0; + it->vlen = 0; + + switch (iter_kind) { + case BTF_FIELD_ITER_IDS: + switch (btf_kind(t)) { + case BTF_KIND_UNKN: + case BTF_KIND_INT: + case BTF_KIND_FLOAT: + case BTF_KIND_ENUM: + case BTF_KIND_ENUM64: + it->desc = (struct btf_field_desc) {}; + break; + case BTF_KIND_FWD: + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_TYPEDEF: + case BTF_KIND_FUNC: + case BTF_KIND_VAR: + case BTF_KIND_DECL_TAG: + case BTF_KIND_TYPE_TAG: + it->desc = (struct btf_field_desc) { 1, {offsetof(struct btf_type, type)} }; + break; + case BTF_KIND_ARRAY: + it->desc = (struct btf_field_desc) { + 2, {sizeof(struct btf_type) + offsetof(struct btf_array, type), + sizeof(struct btf_type) + offsetof(struct btf_array, index_type)} + }; + break; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + it->desc = (struct btf_field_desc) { + 0, {}, + sizeof(struct btf_member), + 1, {offsetof(struct btf_member, type)} + }; + break; + case BTF_KIND_FUNC_PROTO: + it->desc = (struct btf_field_desc) { + 1, {offsetof(struct btf_type, type)}, + sizeof(struct btf_param), + 1, {offsetof(struct btf_param, type)} + }; + break; + case BTF_KIND_DATASEC: + it->desc = (struct btf_field_desc) { + 0, {}, + sizeof(struct btf_var_secinfo), + 1, {offsetof(struct btf_var_secinfo, type)} + }; + break; + default: + return -EINVAL; + } + break; + case BTF_FIELD_ITER_STRS: + switch (btf_kind(t)) { + case BTF_KIND_UNKN: + it->desc = (struct btf_field_desc) {}; + break; + case BTF_KIND_INT: + case BTF_KIND_FLOAT: + case BTF_KIND_FWD: + case BTF_KIND_ARRAY: + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_TYPEDEF: + case BTF_KIND_FUNC: + case BTF_KIND_VAR: + case BTF_KIND_DECL_TAG: + case BTF_KIND_TYPE_TAG: + case BTF_KIND_DATASEC: + it->desc = (struct btf_field_desc) { + 1, {offsetof(struct btf_type, name_off)} + }; + break; + case BTF_KIND_ENUM: + it->desc = (struct btf_field_desc) { + 1, {offsetof(struct btf_type, name_off)}, + sizeof(struct btf_enum), + 1, {offsetof(struct btf_enum, name_off)} + }; + break; + case BTF_KIND_ENUM64: + it->desc = (struct btf_field_desc) { + 1, {offsetof(struct btf_type, name_off)}, + sizeof(struct btf_enum64), + 1, {offsetof(struct btf_enum64, name_off)} + }; + break; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + it->desc = (struct btf_field_desc) { + 1, {offsetof(struct btf_type, name_off)}, + sizeof(struct btf_member), + 1, {offsetof(struct btf_member, name_off)} + }; + break; + case BTF_KIND_FUNC_PROTO: + it->desc = (struct btf_field_desc) { + 1, {offsetof(struct btf_type, name_off)}, + sizeof(struct btf_param), + 1, {offsetof(struct btf_param, name_off)} + }; + break; + default: + return -EINVAL; + } + break; + default: + return -EINVAL; + } + + if (it->desc.m_sz) + it->vlen = btf_vlen(t); + + it->p = t; + return 0; +} + +__u32 *btf_field_iter_next(struct btf_field_iter *it) +{ + if (!it->p) + return NULL; + + if (it->m_idx < 0) { + if (it->off_idx < it->desc.t_cnt) + return it->p + it->desc.t_offs[it->off_idx++]; + /* move to per-member iteration */ + it->m_idx = 0; + it->p += sizeof(struct btf_type); + it->off_idx = 0; + } + + /* if type doesn't have members, stop */ + if (it->desc.m_sz == 0) { + it->p = NULL; + return NULL; + } + + if (it->off_idx >= it->desc.m_cnt) { + /* exhausted this member's fields, go to the next member */ + it->m_idx++; + it->p += it->desc.m_sz; + it->off_idx = 0; + } + + if (it->m_idx < it->vlen) + return it->p + it->desc.m_offs[it->off_idx++]; + + it->p = NULL; + return NULL; +} + int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx) { const struct btf_ext_info *seg; diff --git a/src/libbpf_internal.h b/src/libbpf_internal.h index 7e7e686..80f3d34 100644 --- a/src/libbpf_internal.h +++ b/src/libbpf_internal.h @@ -508,6 +508,30 @@ struct bpf_line_info_min { __u32 line_col; }; +enum btf_field_iter_kind { + BTF_FIELD_ITER_IDS, + BTF_FIELD_ITER_STRS, +}; + +struct btf_field_desc { + /* once-per-type offsets */ + int t_cnt, t_offs[2]; + /* member struct size, or zero, if no members */ + int m_sz; + /* repeated per-member offsets */ + int m_cnt, m_offs[1]; +}; + +struct btf_field_iter { + struct btf_field_desc desc; + void *p; + int m_idx; + int off_idx; + int vlen; +}; + +int btf_field_iter_init(struct btf_field_iter *it, struct btf_type *t, enum btf_field_iter_kind iter_kind); +__u32 *btf_field_iter_next(struct btf_field_iter *it); typedef int (*type_id_visit_fn)(__u32 *type_id, void *ctx); typedef int (*str_off_visit_fn)(__u32 *str_off, void *ctx); From 13182b94f3a2ccfd727b76ca899ce87e50851874 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 4 Jun 2024 17:16:26 -0700 Subject: [PATCH 04/26] libbpf: Make use of BTF field iterator in BPF linker code Switch all BPF linker code dealing with iterating BTF type ID and string offset fields to new btf_field_iter facilities. Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Tested-by: Alan Maguire Acked-by: Eduard Zingerman Acked-by: Jiri Olsa Link: https://lore.kernel.org/bpf/20240605001629.4061937-3-andrii@kernel.org --- src/btf.c | 4 +-- src/libbpf_internal.h | 4 +-- src/linker.c | 58 +++++++++++++++++++++++++++---------------- 3 files changed, 40 insertions(+), 26 deletions(-) diff --git a/src/btf.c b/src/btf.c index 50ff8b6..d72260a 100644 --- a/src/btf.c +++ b/src/btf.c @@ -5267,7 +5267,7 @@ __u32 *btf_field_iter_next(struct btf_field_iter *it) return NULL; if (it->m_idx < 0) { - if (it->off_idx < it->desc.t_cnt) + if (it->off_idx < it->desc.t_off_cnt) return it->p + it->desc.t_offs[it->off_idx++]; /* move to per-member iteration */ it->m_idx = 0; @@ -5281,7 +5281,7 @@ __u32 *btf_field_iter_next(struct btf_field_iter *it) return NULL; } - if (it->off_idx >= it->desc.m_cnt) { + if (it->off_idx >= it->desc.m_off_cnt) { /* exhausted this member's fields, go to the next member */ it->m_idx++; it->p += it->desc.m_sz; diff --git a/src/libbpf_internal.h b/src/libbpf_internal.h index 80f3d34..96c0b09 100644 --- a/src/libbpf_internal.h +++ b/src/libbpf_internal.h @@ -515,11 +515,11 @@ enum btf_field_iter_kind { struct btf_field_desc { /* once-per-type offsets */ - int t_cnt, t_offs[2]; + int t_off_cnt, t_offs[2]; /* member struct size, or zero, if no members */ int m_sz; /* repeated per-member offsets */ - int m_cnt, m_offs[1]; + int m_off_cnt, m_offs[1]; }; struct btf_field_iter { diff --git a/src/linker.c b/src/linker.c index 0d4be82..fa11a67 100644 --- a/src/linker.c +++ b/src/linker.c @@ -957,19 +957,33 @@ static int check_btf_str_off(__u32 *str_off, void *ctx) static int linker_sanity_check_btf(struct src_obj *obj) { struct btf_type *t; - int i, n, err = 0; + int i, n, err; if (!obj->btf) return 0; n = btf__type_cnt(obj->btf); for (i = 1; i < n; i++) { + struct btf_field_iter it; + __u32 *type_id, *str_off; + t = btf_type_by_id(obj->btf, i); - err = err ?: btf_type_visit_type_ids(t, check_btf_type_id, obj->btf); - err = err ?: btf_type_visit_str_offs(t, check_btf_str_off, obj->btf); + err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_IDS); if (err) return err; + while ((type_id = btf_field_iter_next(&it))) { + if (*type_id >= n) + return -EINVAL; + } + + err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_STRS); + if (err) + return err; + while ((str_off = btf_field_iter_next(&it))) { + if (!btf__str_by_offset(obj->btf, *str_off)) + return -EINVAL; + } } return 0; @@ -2234,26 +2248,10 @@ static int linker_fixup_btf(struct src_obj *obj) return 0; } -static int remap_type_id(__u32 *type_id, void *ctx) -{ - int *id_map = ctx; - int new_id = id_map[*type_id]; - - /* Error out if the type wasn't remapped. Ignore VOID which stays VOID. */ - if (new_id == 0 && *type_id != 0) { - pr_warn("failed to find new ID mapping for original BTF type ID %u\n", *type_id); - return -EINVAL; - } - - *type_id = id_map[*type_id]; - - return 0; -} - static int linker_append_btf(struct bpf_linker *linker, struct src_obj *obj) { const struct btf_type *t; - int i, j, n, start_id, id; + int i, j, n, start_id, id, err; const char *name; if (!obj->btf) @@ -2324,9 +2322,25 @@ static int linker_append_btf(struct bpf_linker *linker, struct src_obj *obj) n = btf__type_cnt(linker->btf); for (i = start_id; i < n; i++) { struct btf_type *dst_t = btf_type_by_id(linker->btf, i); + struct btf_field_iter it; + __u32 *type_id; - if (btf_type_visit_type_ids(dst_t, remap_type_id, obj->btf_type_map)) - return -EINVAL; + err = btf_field_iter_init(&it, dst_t, BTF_FIELD_ITER_IDS); + if (err) + return err; + + while ((type_id = btf_field_iter_next(&it))) { + int new_id = obj->btf_type_map[*type_id]; + + /* Error out if the type wasn't remapped. Ignore VOID which stays VOID. */ + if (new_id == 0 && *type_id != 0) { + pr_warn("failed to find new ID mapping for original BTF type ID %u\n", + *type_id); + return -EINVAL; + } + + *type_id = obj->btf_type_map[*type_id]; + } } /* Rewrite VAR/FUNC underlying types (i.e., FUNC's FUNC_PROTO and VAR's From dd19c7ef772da7ab7522fba17bb3576e9d569a14 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 4 Jun 2024 17:16:27 -0700 Subject: [PATCH 05/26] libbpf: Make use of BTF field iterator in BTF handling code Use new BTF field iterator logic to replace all the callback-based visitor calls. There is still a .BTF.ext callback-based visitor APIs that should be converted, which will happens as a follow up. Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Tested-by: Alan Maguire Acked-by: Eduard Zingerman Acked-by: Jiri Olsa Link: https://lore.kernel.org/bpf/20240605001629.4061937-4-andrii@kernel.org --- src/btf.c | 82 ++++++++++++++++++++++++++++++++++++++----------------- 1 file changed, 57 insertions(+), 25 deletions(-) diff --git a/src/btf.c b/src/btf.c index d72260a..0190fd8 100644 --- a/src/btf.c +++ b/src/btf.c @@ -1739,9 +1739,8 @@ struct btf_pipe { struct hashmap *str_off_map; /* map string offsets from src to dst */ }; -static int btf_rewrite_str(__u32 *str_off, void *ctx) +static int btf_rewrite_str(struct btf_pipe *p, __u32 *str_off) { - struct btf_pipe *p = ctx; long mapped_off; int off, err; @@ -1774,7 +1773,9 @@ static int btf_rewrite_str(__u32 *str_off, void *ctx) int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_type *src_type) { struct btf_pipe p = { .src = src_btf, .dst = btf }; + struct btf_field_iter it; struct btf_type *t; + __u32 *str_off; int sz, err; sz = btf_type_size(src_type); @@ -1791,28 +1792,19 @@ int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_t memcpy(t, src_type, sz); - err = btf_type_visit_str_offs(t, btf_rewrite_str, &p); + err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_STRS); if (err) return libbpf_err(err); + while ((str_off = btf_field_iter_next(&it))) { + err = btf_rewrite_str(&p, str_off); + if (err) + return libbpf_err(err); + } + return btf_commit_type(btf, sz); } -static int btf_rewrite_type_ids(__u32 *type_id, void *ctx) -{ - struct btf *btf = ctx; - - if (!*type_id) /* nothing to do for VOID references */ - return 0; - - /* we haven't updated btf's type count yet, so - * btf->start_id + btf->nr_types - 1 is the type ID offset we should - * add to all newly added BTF types - */ - *type_id += btf->start_id + btf->nr_types - 1; - return 0; -} - static size_t btf_dedup_identity_hash_fn(long key, void *ctx); static bool btf_dedup_equal_fn(long k1, long k2, void *ctx); @@ -1858,6 +1850,9 @@ int btf__add_btf(struct btf *btf, const struct btf *src_btf) memcpy(t, src_btf->types_data, data_sz); for (i = 0; i < cnt; i++) { + struct btf_field_iter it; + __u32 *type_id, *str_off; + sz = btf_type_size(t); if (sz < 0) { /* unlikely, has to be corrupted src_btf */ @@ -1869,14 +1864,30 @@ int btf__add_btf(struct btf *btf, const struct btf *src_btf) *off = t - btf->types_data; /* add, dedup, and remap strings referenced by this BTF type */ - err = btf_type_visit_str_offs(t, btf_rewrite_str, &p); + err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_STRS); + if (err) + goto err_out; + while ((str_off = btf_field_iter_next(&it))) { + err = btf_rewrite_str(&p, str_off); + if (err) + goto err_out; + } + + /* remap all type IDs referenced from this BTF type */ + err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_IDS); if (err) goto err_out; - /* remap all type IDs referenced from this BTF type */ - err = btf_type_visit_type_ids(t, btf_rewrite_type_ids, btf); - if (err) - goto err_out; + while ((type_id = btf_field_iter_next(&it))) { + if (!*type_id) /* nothing to do for VOID references */ + continue; + + /* we haven't updated btf's type count yet, so + * btf->start_id + btf->nr_types - 1 is the type ID offset we should + * add to all newly added BTF types + */ + *type_id += btf->start_id + btf->nr_types - 1; + } /* go to next type data and type offset index entry */ t += sz; @@ -3453,11 +3464,19 @@ static int btf_for_each_str_off(struct btf_dedup *d, str_off_visit_fn fn, void * int i, r; for (i = 0; i < d->btf->nr_types; i++) { + struct btf_field_iter it; struct btf_type *t = btf_type_by_id(d->btf, d->btf->start_id + i); + __u32 *str_off; - r = btf_type_visit_str_offs(t, fn, ctx); + r = btf_field_iter_init(&it, t, BTF_FIELD_ITER_STRS); if (r) return r; + + while ((str_off = btf_field_iter_next(&it))) { + r = fn(str_off, ctx); + if (r) + return r; + } } if (!d->btf_ext) @@ -4919,10 +4938,23 @@ static int btf_dedup_remap_types(struct btf_dedup *d) for (i = 0; i < d->btf->nr_types; i++) { struct btf_type *t = btf_type_by_id(d->btf, d->btf->start_id + i); + struct btf_field_iter it; + __u32 *type_id; - r = btf_type_visit_type_ids(t, btf_dedup_remap_type_id, d); + r = btf_field_iter_init(&it, t, BTF_FIELD_ITER_IDS); if (r) return r; + + while ((type_id = btf_field_iter_next(&it))) { + __u32 resolved_id, new_id; + + resolved_id = resolve_type_id(d, *type_id); + new_id = d->hypot_map[resolved_id]; + if (new_id > BTF_MAX_NR_TYPES) + return -EINVAL; + + *type_id = new_id; + } } if (!d->btf_ext) From 78c78e90cd7f78e0b303c2c06c9ba9e509bfa947 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 4 Jun 2024 17:16:29 -0700 Subject: [PATCH 06/26] libbpf: Remove callback-based type/string BTF field visitor helpers Now that all libbpf/bpftool code switched to btf_field_iter, remove btf_type_visit_type_ids() and btf_type_visit_str_offs() callback-based helpers as not needed anymore. Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Tested-by: Alan Maguire Acked-by: Eduard Zingerman Acked-by: Jiri Olsa Link: https://lore.kernel.org/bpf/20240605001629.4061937-6-andrii@kernel.org --- src/btf.c | 130 ------------------------------------------ src/libbpf_internal.h | 2 - 2 files changed, 132 deletions(-) diff --git a/src/btf.c b/src/btf.c index 0190fd8..775ca55 100644 --- a/src/btf.c +++ b/src/btf.c @@ -5035,136 +5035,6 @@ struct btf *btf__load_module_btf(const char *module_name, struct btf *vmlinux_bt return btf__parse_split(path, vmlinux_btf); } -int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ctx) -{ - int i, n, err; - - switch (btf_kind(t)) { - case BTF_KIND_INT: - case BTF_KIND_FLOAT: - case BTF_KIND_ENUM: - case BTF_KIND_ENUM64: - return 0; - - case BTF_KIND_FWD: - case BTF_KIND_CONST: - case BTF_KIND_VOLATILE: - case BTF_KIND_RESTRICT: - case BTF_KIND_PTR: - case BTF_KIND_TYPEDEF: - case BTF_KIND_FUNC: - case BTF_KIND_VAR: - case BTF_KIND_DECL_TAG: - case BTF_KIND_TYPE_TAG: - return visit(&t->type, ctx); - - case BTF_KIND_ARRAY: { - struct btf_array *a = btf_array(t); - - err = visit(&a->type, ctx); - err = err ?: visit(&a->index_type, ctx); - return err; - } - - case BTF_KIND_STRUCT: - case BTF_KIND_UNION: { - struct btf_member *m = btf_members(t); - - for (i = 0, n = btf_vlen(t); i < n; i++, m++) { - err = visit(&m->type, ctx); - if (err) - return err; - } - return 0; - } - - case BTF_KIND_FUNC_PROTO: { - struct btf_param *m = btf_params(t); - - err = visit(&t->type, ctx); - if (err) - return err; - for (i = 0, n = btf_vlen(t); i < n; i++, m++) { - err = visit(&m->type, ctx); - if (err) - return err; - } - return 0; - } - - case BTF_KIND_DATASEC: { - struct btf_var_secinfo *m = btf_var_secinfos(t); - - for (i = 0, n = btf_vlen(t); i < n; i++, m++) { - err = visit(&m->type, ctx); - if (err) - return err; - } - return 0; - } - - default: - return -EINVAL; - } -} - -int btf_type_visit_str_offs(struct btf_type *t, str_off_visit_fn visit, void *ctx) -{ - int i, n, err; - - err = visit(&t->name_off, ctx); - if (err) - return err; - - switch (btf_kind(t)) { - case BTF_KIND_STRUCT: - case BTF_KIND_UNION: { - struct btf_member *m = btf_members(t); - - for (i = 0, n = btf_vlen(t); i < n; i++, m++) { - err = visit(&m->name_off, ctx); - if (err) - return err; - } - break; - } - case BTF_KIND_ENUM: { - struct btf_enum *m = btf_enum(t); - - for (i = 0, n = btf_vlen(t); i < n; i++, m++) { - err = visit(&m->name_off, ctx); - if (err) - return err; - } - break; - } - case BTF_KIND_ENUM64: { - struct btf_enum64 *m = btf_enum64(t); - - for (i = 0, n = btf_vlen(t); i < n; i++, m++) { - err = visit(&m->name_off, ctx); - if (err) - return err; - } - break; - } - case BTF_KIND_FUNC_PROTO: { - struct btf_param *m = btf_params(t); - - for (i = 0, n = btf_vlen(t); i < n; i++, m++) { - err = visit(&m->name_off, ctx); - if (err) - return err; - } - break; - } - default: - break; - } - - return 0; -} - int btf_field_iter_init(struct btf_field_iter *it, struct btf_type *t, enum btf_field_iter_kind iter_kind) { it->p = NULL; diff --git a/src/libbpf_internal.h b/src/libbpf_internal.h index 96c0b09..e2f0660 100644 --- a/src/libbpf_internal.h +++ b/src/libbpf_internal.h @@ -535,8 +535,6 @@ __u32 *btf_field_iter_next(struct btf_field_iter *it); typedef int (*type_id_visit_fn)(__u32 *type_id, void *ctx); typedef int (*str_off_visit_fn)(__u32 *str_off, void *ctx); -int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ctx); -int btf_type_visit_str_offs(struct btf_type *t, str_off_visit_fn visit, void *ctx); int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx); int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void *ctx); __s32 btf__find_by_name_kind_own(const struct btf *btf, const char *type_name, From be998aa3d41e1f5f83e3e69a71746b785e0a7b8b Mon Sep 17 00:00:00 2001 From: Mykyta Yatsenko Date: Wed, 5 Jun 2024 18:51:35 +0100 Subject: [PATCH 07/26] libbpf: Auto-attach struct_ops BPF maps in BPF skeleton Similarly to `bpf_program`, support `bpf_map` automatic attachment in `bpf_object__attach_skeleton`. Currently only struct_ops maps could be attached. On bpftool side, code-generate links in skeleton struct for struct_ops maps. Similarly to `bpf_program_skeleton`, set links in `bpf_map_skeleton`. On libbpf side, extend `bpf_map` with new `autoattach` field to support enabling or disabling autoattach functionality, introducing getter/setter for this field. `bpf_object__(attach|detach)_skeleton` is extended with attaching/detaching struct_ops maps logic. Signed-off-by: Mykyta Yatsenko Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20240605175135.117127-1-yatsenko@meta.com --- src/libbpf.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++--- src/libbpf.h | 18 ++++++++++++++ src/libbpf.map | 2 ++ 3 files changed, 81 insertions(+), 3 deletions(-) diff --git a/src/libbpf.c b/src/libbpf.c index d1627a2..4a28fac 100644 --- a/src/libbpf.c +++ b/src/libbpf.c @@ -572,6 +572,7 @@ struct bpf_map { bool pinned; bool reused; bool autocreate; + bool autoattach; __u64 map_extra; }; @@ -1400,6 +1401,7 @@ static int init_struct_ops_maps(struct bpf_object *obj, const char *sec_name, map->def.value_size = type->size; map->def.max_entries = 1; map->def.map_flags = strcmp(sec_name, STRUCT_OPS_LINK_SEC) == 0 ? BPF_F_LINK : 0; + map->autoattach = true; map->st_ops = calloc(1, sizeof(*map->st_ops)); if (!map->st_ops) @@ -4819,6 +4821,20 @@ int bpf_map__set_autocreate(struct bpf_map *map, bool autocreate) return 0; } +int bpf_map__set_autoattach(struct bpf_map *map, bool autoattach) +{ + if (!bpf_map__is_struct_ops(map)) + return libbpf_err(-EINVAL); + + map->autoattach = autoattach; + return 0; +} + +bool bpf_map__autoattach(const struct bpf_map *map) +{ + return map->autoattach; +} + int bpf_map__reuse_fd(struct bpf_map *map, int fd) { struct bpf_map_info info; @@ -12900,8 +12916,10 @@ struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map) __u32 zero = 0; int err, fd; - if (!bpf_map__is_struct_ops(map)) + if (!bpf_map__is_struct_ops(map)) { + pr_warn("map '%s': can't attach non-struct_ops map\n", map->name); return libbpf_err_ptr(-EINVAL); + } if (map->fd < 0) { pr_warn("map '%s': can't attach BPF map without FD (was it created?)\n", map->name); @@ -13945,6 +13963,35 @@ int bpf_object__attach_skeleton(struct bpf_object_skeleton *s) */ } + /* Skeleton is created with earlier version of bpftool + * which does not support auto-attachment + */ + if (s->map_skel_sz < sizeof(struct bpf_map_skeleton)) + return 0; + + for (i = 0; i < s->map_cnt; i++) { + struct bpf_map *map = *s->maps[i].map; + struct bpf_link **link = s->maps[i].link; + + if (!map->autocreate || !map->autoattach) + continue; + + if (*link) + continue; + + /* only struct_ops maps can be attached */ + if (!bpf_map__is_struct_ops(map)) + continue; + *link = bpf_map__attach_struct_ops(map); + + if (!*link) { + err = -errno; + pr_warn("map '%s': failed to auto-attach: %d\n", + bpf_map__name(map), err); + return libbpf_err(err); + } + } + return 0; } @@ -13958,6 +14005,18 @@ void bpf_object__detach_skeleton(struct bpf_object_skeleton *s) bpf_link__destroy(*link); *link = NULL; } + + if (s->map_skel_sz < sizeof(struct bpf_map_skeleton)) + return; + + for (i = 0; i < s->map_cnt; i++) { + struct bpf_link **link = s->maps[i].link; + + if (link) { + bpf_link__destroy(*link); + *link = NULL; + } + } } void bpf_object__destroy_skeleton(struct bpf_object_skeleton *s) @@ -13965,8 +14024,7 @@ void bpf_object__destroy_skeleton(struct bpf_object_skeleton *s) if (!s) return; - if (s->progs) - bpf_object__detach_skeleton(s); + bpf_object__detach_skeleton(s); if (s->obj) bpf_object__close(*s->obj); free(s->maps); diff --git a/src/libbpf.h b/src/libbpf.h index 26e4e35..64a6a3d 100644 --- a/src/libbpf.h +++ b/src/libbpf.h @@ -978,6 +978,23 @@ bpf_object__prev_map(const struct bpf_object *obj, const struct bpf_map *map); LIBBPF_API int bpf_map__set_autocreate(struct bpf_map *map, bool autocreate); LIBBPF_API bool bpf_map__autocreate(const struct bpf_map *map); +/** + * @brief **bpf_map__set_autoattach()** sets whether libbpf has to auto-attach + * map during BPF skeleton attach phase. + * @param map the BPF map instance + * @param autoattach whether to attach map during BPF skeleton attach phase + * @return 0 on success; negative error code, otherwise + */ +LIBBPF_API int bpf_map__set_autoattach(struct bpf_map *map, bool autoattach); + +/** + * @brief **bpf_map__autoattach()** returns whether BPF map is configured to + * auto-attach during BPF skeleton attach phase. + * @param map the BPF map instance + * @return true if map is set to auto-attach during skeleton attach phase; false, otherwise + */ +LIBBPF_API bool bpf_map__autoattach(const struct bpf_map *map); + /** * @brief **bpf_map__fd()** gets the file descriptor of the passed * BPF map @@ -1672,6 +1689,7 @@ struct bpf_map_skeleton { const char *name; struct bpf_map **map; void **mmaped; + struct bpf_link **link; }; struct bpf_prog_skeleton { diff --git a/src/libbpf.map b/src/libbpf.map index c1ce8aa..4059523 100644 --- a/src/libbpf.map +++ b/src/libbpf.map @@ -419,6 +419,8 @@ LIBBPF_1.4.0 { LIBBPF_1.5.0 { global: + bpf_map__autoattach; + bpf_map__set_autoattach; bpf_program__attach_sockmap; ring__consume_n; ring_buffer__consume_n; From 0a66859bf18dff68ba569e85f43479954a6cee09 Mon Sep 17 00:00:00 2001 From: Vadim Fedorenko Date: Thu, 6 Jun 2024 07:58:50 -0700 Subject: [PATCH 08/26] bpf: Add CHECKSUM_COMPLETE to bpf test progs Add special flag to validate that TC BPF program properly updates checksum information in skb. Signed-off-by: Vadim Fedorenko Signed-off-by: Daniel Borkmann Reviewed-by: Jakub Kicinski Acked-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20240606145851.229116-1-vadfed@meta.com --- include/uapi/linux/bpf.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 25ea393..35bcf52 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1425,6 +1425,8 @@ enum { #define BPF_F_TEST_RUN_ON_CPU (1U << 0) /* If set, XDP frames will be transmitted after processing */ #define BPF_F_TEST_XDP_LIVE_FRAMES (1U << 1) +/* If set, apply CHECKSUM_COMPLETE to skb and validate the checksum */ +#define BPF_F_TEST_SKB_CHECKSUM_COMPLETE (1U << 2) /* type for BPF_ENABLE_STATS */ enum bpf_stats_type { From 36cb1ad3aea161d60eda6c818ecc882df5ff842e Mon Sep 17 00:00:00 2001 From: Alan Maguire Date: Thu, 13 Jun 2024 10:50:06 +0100 Subject: [PATCH 09/26] libbpf: Add btf__distill_base() creating split BTF with distilled base BTF To support more robust split BTF, adding supplemental context for the base BTF type ids that split BTF refers to is required. Without such references, a simple shuffling of base BTF type ids (without any other significant change) invalidates the split BTF. Here the attempt is made to store additional context to make split BTF more robust. This context comes in the form of distilled base BTF providing minimal information (name and - in some cases - size) for base INTs, FLOATs, STRUCTs, UNIONs, ENUMs and ENUM64s along with modified split BTF that points at that base and contains any additional types needed (such as TYPEDEF, PTR and anonymous STRUCT/UNION declarations). This information constitutes the minimal BTF representation needed to disambiguate or remove split BTF references to base BTF. The rules are as follows: - INT, FLOAT, FWD are recorded in full. - if a named base BTF STRUCT or UNION is referred to from split BTF, it will be encoded as a zero-member sized STRUCT/UNION (preserving size for later relocation checks). Only base BTF STRUCT/UNIONs that are either embedded in split BTF STRUCT/UNIONs or that have multiple STRUCT/UNION instances of the same name will _need_ size checks at relocation time, but as it is possible a different set of types will be duplicates in the later to-be-resolved base BTF, we preserve size information for all named STRUCT/UNIONs. - if an ENUM[64] is named, a ENUM forward representation (an ENUM with no values) of the same size is used. - in all other cases, the type is added to the new split BTF. Avoiding struct/union/enum/enum64 expansion is important to keep the distilled base BTF representation to a minimum size. When successful, new representations of the distilled base BTF and new split BTF that refers to it are returned. Both need to be freed by the caller. So to take a simple example, with split BTF with a type referring to "struct sk_buff", we will generate distilled base BTF with a 0-member STRUCT sk_buff of the appropriate size, and the split BTF will refer to it instead. Tools like pahole can utilize such split BTF to populate the .BTF section (split BTF) and an additional .BTF.base section. Then when the split BTF is loaded, the distilled base BTF can be used to relocate split BTF to reference the current (and possibly changed) base BTF. So for example if "struct sk_buff" was id 502 when the split BTF was originally generated, we can use the distilled base BTF to see that id 502 refers to a "struct sk_buff" and replace instances of id 502 with the current (relocated) base BTF sk_buff type id. Distilled base BTF is small; when building a kernel with all modules using distilled base BTF as a test, overall module size grew by only 5.3Mb total across ~2700 modules. Signed-off-by: Alan Maguire Signed-off-by: Andrii Nakryiko Acked-by: Eduard Zingerman Link: https://lore.kernel.org/bpf/20240613095014.357981-2-alan.maguire@oracle.com --- src/btf.c | 319 ++++++++++++++++++++++++++++++++++++++++++++++++- src/btf.h | 21 ++++ src/libbpf.map | 1 + 3 files changed, 335 insertions(+), 6 deletions(-) diff --git a/src/btf.c b/src/btf.c index 775ca55..407ed92 100644 --- a/src/btf.c +++ b/src/btf.c @@ -1770,9 +1770,8 @@ static int btf_rewrite_str(struct btf_pipe *p, __u32 *str_off) return 0; } -int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_type *src_type) +static int btf_add_type(struct btf_pipe *p, const struct btf_type *src_type) { - struct btf_pipe p = { .src = src_btf, .dst = btf }; struct btf_field_iter it; struct btf_type *t; __u32 *str_off; @@ -1783,10 +1782,10 @@ int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_t return libbpf_err(sz); /* deconstruct BTF, if necessary, and invalidate raw_data */ - if (btf_ensure_modifiable(btf)) + if (btf_ensure_modifiable(p->dst)) return libbpf_err(-ENOMEM); - t = btf_add_type_mem(btf, sz); + t = btf_add_type_mem(p->dst, sz); if (!t) return libbpf_err(-ENOMEM); @@ -1797,12 +1796,19 @@ int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_t return libbpf_err(err); while ((str_off = btf_field_iter_next(&it))) { - err = btf_rewrite_str(&p, str_off); + err = btf_rewrite_str(p, str_off); if (err) return libbpf_err(err); } - return btf_commit_type(btf, sz); + return btf_commit_type(p->dst, sz); +} + +int btf__add_type(struct btf *btf, const struct btf *src_btf, const struct btf_type *src_type) +{ + struct btf_pipe p = { .src = src_btf, .dst = btf }; + + return btf_add_type(&p, src_type); } static size_t btf_dedup_identity_hash_fn(long key, void *ctx); @@ -5276,3 +5282,304 @@ int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void return 0; } + +struct btf_distill { + struct btf_pipe pipe; + int *id_map; + unsigned int split_start_id; + unsigned int split_start_str; + int diff_id; +}; + +static int btf_add_distilled_type_ids(struct btf_distill *dist, __u32 i) +{ + struct btf_type *split_t = btf_type_by_id(dist->pipe.src, i); + struct btf_field_iter it; + __u32 *id; + int err; + + err = btf_field_iter_init(&it, split_t, BTF_FIELD_ITER_IDS); + if (err) + return err; + while ((id = btf_field_iter_next(&it))) { + struct btf_type *base_t; + + if (!*id) + continue; + /* split BTF id, not needed */ + if (*id >= dist->split_start_id) + continue; + /* already added ? */ + if (dist->id_map[*id] > 0) + continue; + + /* only a subset of base BTF types should be referenced from + * split BTF; ensure nothing unexpected is referenced. + */ + base_t = btf_type_by_id(dist->pipe.src, *id); + switch (btf_kind(base_t)) { + case BTF_KIND_INT: + case BTF_KIND_FLOAT: + case BTF_KIND_FWD: + case BTF_KIND_ARRAY: + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + case BTF_KIND_TYPEDEF: + case BTF_KIND_ENUM: + case BTF_KIND_ENUM64: + case BTF_KIND_PTR: + case BTF_KIND_CONST: + case BTF_KIND_RESTRICT: + case BTF_KIND_VOLATILE: + case BTF_KIND_FUNC_PROTO: + case BTF_KIND_TYPE_TAG: + dist->id_map[*id] = *id; + break; + default: + pr_warn("unexpected reference to base type[%u] of kind [%u] when creating distilled base BTF.\n", + *id, btf_kind(base_t)); + return -EINVAL; + } + /* If a base type is used, ensure types it refers to are + * marked as used also; so for example if we find a PTR to INT + * we need both the PTR and INT. + * + * The only exception is named struct/unions, since distilled + * base BTF composite types have no members. + */ + if (btf_is_composite(base_t) && base_t->name_off) + continue; + err = btf_add_distilled_type_ids(dist, *id); + if (err) + return err; + } + return 0; +} + +static int btf_add_distilled_types(struct btf_distill *dist) +{ + bool adding_to_base = dist->pipe.dst->start_id == 1; + int id = btf__type_cnt(dist->pipe.dst); + struct btf_type *t; + int i, err = 0; + + + /* Add types for each of the required references to either distilled + * base or split BTF, depending on type characteristics. + */ + for (i = 1; i < dist->split_start_id; i++) { + const char *name; + int kind; + + if (!dist->id_map[i]) + continue; + t = btf_type_by_id(dist->pipe.src, i); + kind = btf_kind(t); + name = btf__name_by_offset(dist->pipe.src, t->name_off); + + switch (kind) { + case BTF_KIND_INT: + case BTF_KIND_FLOAT: + case BTF_KIND_FWD: + /* Named int, float, fwd are added to base. */ + if (!adding_to_base) + continue; + err = btf_add_type(&dist->pipe, t); + break; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + /* Named struct/union are added to base as 0-vlen + * struct/union of same size. Anonymous struct/unions + * are added to split BTF as-is. + */ + if (adding_to_base) { + if (!t->name_off) + continue; + err = btf_add_composite(dist->pipe.dst, kind, name, t->size); + } else { + if (t->name_off) + continue; + err = btf_add_type(&dist->pipe, t); + } + break; + case BTF_KIND_ENUM: + case BTF_KIND_ENUM64: + /* Named enum[64]s are added to base as a sized + * enum; relocation will match with appropriately-named + * and sized enum or enum64. + * + * Anonymous enums are added to split BTF as-is. + */ + if (adding_to_base) { + if (!t->name_off) + continue; + err = btf__add_enum(dist->pipe.dst, name, t->size); + } else { + if (t->name_off) + continue; + err = btf_add_type(&dist->pipe, t); + } + break; + case BTF_KIND_ARRAY: + case BTF_KIND_TYPEDEF: + case BTF_KIND_PTR: + case BTF_KIND_CONST: + case BTF_KIND_RESTRICT: + case BTF_KIND_VOLATILE: + case BTF_KIND_FUNC_PROTO: + case BTF_KIND_TYPE_TAG: + /* All other types are added to split BTF. */ + if (adding_to_base) + continue; + err = btf_add_type(&dist->pipe, t); + break; + default: + pr_warn("unexpected kind when adding base type '%s'[%u] of kind [%u] to distilled base BTF.\n", + name, i, kind); + return -EINVAL; + + } + if (err < 0) + break; + dist->id_map[i] = id++; + } + return err; +} + +/* Split BTF ids without a mapping will be shifted downwards since distilled + * base BTF is smaller than the original base BTF. For those that have a + * mapping (either to base or updated split BTF), update the id based on + * that mapping. + */ +static int btf_update_distilled_type_ids(struct btf_distill *dist, __u32 i) +{ + struct btf_type *t = btf_type_by_id(dist->pipe.dst, i); + struct btf_field_iter it; + __u32 *id; + int err; + + err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_IDS); + if (err) + return err; + while ((id = btf_field_iter_next(&it))) { + if (dist->id_map[*id]) + *id = dist->id_map[*id]; + else if (*id >= dist->split_start_id) + *id -= dist->diff_id; + } + return 0; +} + +/* Create updated split BTF with distilled base BTF; distilled base BTF + * consists of BTF information required to clarify the types that split + * BTF refers to, omitting unneeded details. Specifically it will contain + * base types and memberless definitions of named structs, unions and enumerated + * types. Associated reference types like pointers, arrays and anonymous + * structs, unions and enumerated types will be added to split BTF. + * Size is recorded for named struct/unions to help guide matching to the + * target base BTF during later relocation. + * + * The only case where structs, unions or enumerated types are fully represented + * is when they are anonymous; in such cases, the anonymous type is added to + * split BTF in full. + * + * We return newly-created split BTF where the split BTF refers to a newly-created + * distilled base BTF. Both must be freed separately by the caller. + */ +int btf__distill_base(const struct btf *src_btf, struct btf **new_base_btf, + struct btf **new_split_btf) +{ + struct btf *new_base = NULL, *new_split = NULL; + const struct btf *old_base; + unsigned int n = btf__type_cnt(src_btf); + struct btf_distill dist = {}; + struct btf_type *t; + int i, err = 0; + + /* src BTF must be split BTF. */ + old_base = btf__base_btf(src_btf); + if (!new_base_btf || !new_split_btf || !old_base) + return libbpf_err(-EINVAL); + + new_base = btf__new_empty(); + if (!new_base) + return libbpf_err(-ENOMEM); + dist.id_map = calloc(n, sizeof(*dist.id_map)); + if (!dist.id_map) { + err = -ENOMEM; + goto done; + } + dist.pipe.src = src_btf; + dist.pipe.dst = new_base; + dist.pipe.str_off_map = hashmap__new(btf_dedup_identity_hash_fn, btf_dedup_equal_fn, NULL); + if (IS_ERR(dist.pipe.str_off_map)) { + err = -ENOMEM; + goto done; + } + dist.split_start_id = btf__type_cnt(old_base); + dist.split_start_str = old_base->hdr->str_len; + + /* Pass over src split BTF; generate the list of base BTF type ids it + * references; these will constitute our distilled BTF set to be + * distributed over base and split BTF as appropriate. + */ + for (i = src_btf->start_id; i < n; i++) { + err = btf_add_distilled_type_ids(&dist, i); + if (err < 0) + goto done; + } + /* Next add types for each of the required references to base BTF and split BTF + * in turn. + */ + err = btf_add_distilled_types(&dist); + if (err < 0) + goto done; + + /* Create new split BTF with distilled base BTF as its base; the final + * state is split BTF with distilled base BTF that represents enough + * about its base references to allow it to be relocated with the base + * BTF available. + */ + new_split = btf__new_empty_split(new_base); + if (!new_split_btf) { + err = -errno; + goto done; + } + dist.pipe.dst = new_split; + /* First add all split types */ + for (i = src_btf->start_id; i < n; i++) { + t = btf_type_by_id(src_btf, i); + err = btf_add_type(&dist.pipe, t); + if (err < 0) + goto done; + } + /* Now add distilled types to split BTF that are not added to base. */ + err = btf_add_distilled_types(&dist); + if (err < 0) + goto done; + + /* All split BTF ids will be shifted downwards since there are less base + * BTF ids in distilled base BTF. + */ + dist.diff_id = dist.split_start_id - btf__type_cnt(new_base); + + n = btf__type_cnt(new_split); + /* Now update base/split BTF ids. */ + for (i = 1; i < n; i++) { + err = btf_update_distilled_type_ids(&dist, i); + if (err < 0) + break; + } +done: + free(dist.id_map); + hashmap__free(dist.pipe.str_off_map); + if (err) { + btf__free(new_split); + btf__free(new_base); + return libbpf_err(err); + } + *new_base_btf = new_base; + *new_split_btf = new_split; + + return 0; +} diff --git a/src/btf.h b/src/btf.h index 8e6880d..cb08ee9 100644 --- a/src/btf.h +++ b/src/btf.h @@ -107,6 +107,27 @@ LIBBPF_API struct btf *btf__new_empty(void); */ LIBBPF_API struct btf *btf__new_empty_split(struct btf *base_btf); +/** + * @brief **btf__distill_base()** creates new versions of the split BTF + * *src_btf* and its base BTF. The new base BTF will only contain the types + * needed to improve robustness of the split BTF to small changes in base BTF. + * When that split BTF is loaded against a (possibly changed) base, this + * distilled base BTF will help update references to that (possibly changed) + * base BTF. + * + * Both the new split and its associated new base BTF must be freed by + * the caller. + * + * If successful, 0 is returned and **new_base_btf** and **new_split_btf** + * will point at new base/split BTF. Both the new split and its associated + * new base BTF must be freed by the caller. + * + * A negative value is returned on error and the thread-local `errno` variable + * is set to the error code as well. + */ +LIBBPF_API int btf__distill_base(const struct btf *src_btf, struct btf **new_base_btf, + struct btf **new_split_btf); + LIBBPF_API struct btf *btf__parse(const char *path, struct btf_ext **btf_ext); LIBBPF_API struct btf *btf__parse_split(const char *path, struct btf *base_btf); LIBBPF_API struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext); diff --git a/src/libbpf.map b/src/libbpf.map index 4059523..175d153 100644 --- a/src/libbpf.map +++ b/src/libbpf.map @@ -419,6 +419,7 @@ LIBBPF_1.4.0 { LIBBPF_1.5.0 { global: + btf__distill_base; bpf_map__autoattach; bpf_map__set_autoattach; bpf_program__attach_sockmap; From 2afe409348600ba59b31d2aefcdbcb261808ac5c Mon Sep 17 00:00:00 2001 From: Alan Maguire Date: Thu, 13 Jun 2024 10:50:08 +0100 Subject: [PATCH 10/26] libbpf: Split BTF relocation Map distilled base BTF type ids referenced in split BTF and their references to the base BTF passed in, and if the mapping succeeds, reparent the split BTF to the base BTF. Relocation is done by first verifying that distilled base BTF only consists of named INT, FLOAT, ENUM, FWD, STRUCT and UNION kinds; then we sort these to speed lookups. Once sorted, the base BTF is iterated, and for each relevant kind we check for an equivalent in distilled base BTF. When found, the mapping from distilled -> base BTF id and string offset is recorded. In establishing mappings, we need to ensure we check STRUCT/UNION size when the STRUCT/UNION is embedded in a split BTF STRUCT/UNION, and when duplicate names exist for the same STRUCT/UNION. Otherwise size is ignored in matching STRUCT/UNIONs. Once all mappings are established, we can update type ids and string offsets in split BTF and reparent it to the new base. Signed-off-by: Alan Maguire Signed-off-by: Andrii Nakryiko Acked-by: Eduard Zingerman Link: https://lore.kernel.org/bpf/20240613095014.357981-4-alan.maguire@oracle.com --- src/btf.c | 17 ++ src/btf.h | 14 ++ src/btf_relocate.c | 506 ++++++++++++++++++++++++++++++++++++++++++ src/libbpf.map | 1 + src/libbpf_internal.h | 3 + 5 files changed, 541 insertions(+) create mode 100644 src/btf_relocate.c diff --git a/src/btf.c b/src/btf.c index 407ed92..5e20354 100644 --- a/src/btf.c +++ b/src/btf.c @@ -5583,3 +5583,20 @@ done: return 0; } + +const struct btf_header *btf_header(const struct btf *btf) +{ + return btf->hdr; +} + +void btf_set_base_btf(struct btf *btf, const struct btf *base_btf) +{ + btf->base_btf = (struct btf *)base_btf; + btf->start_id = btf__type_cnt(base_btf); + btf->start_str_off = base_btf->hdr->str_len; +} + +int btf__relocate(struct btf *btf, const struct btf *base_btf) +{ + return libbpf_err(btf_relocate(btf, base_btf, NULL)); +} diff --git a/src/btf.h b/src/btf.h index cb08ee9..8a93120 100644 --- a/src/btf.h +++ b/src/btf.h @@ -252,6 +252,20 @@ struct btf_dedup_opts { LIBBPF_API int btf__dedup(struct btf *btf, const struct btf_dedup_opts *opts); +/** + * @brief **btf__relocate()** will check the split BTF *btf* for references + * to base BTF kinds, and verify those references are compatible with + * *base_btf*; if they are, *btf* is adjusted such that is re-parented to + * *base_btf* and type ids and strings are adjusted to accommodate this. + * + * If successful, 0 is returned and **btf** now has **base_btf** as its + * base. + * + * A negative value is returned on error and the thread-local `errno` variable + * is set to the error code as well. + */ +LIBBPF_API int btf__relocate(struct btf *btf, const struct btf *base_btf); + struct btf_dump; struct btf_dump_opts { diff --git a/src/btf_relocate.c b/src/btf_relocate.c new file mode 100644 index 0000000..eabb875 --- /dev/null +++ b/src/btf_relocate.c @@ -0,0 +1,506 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2024, Oracle and/or its affiliates. */ + +#ifndef _GNU_SOURCE +#define _GNU_SOURCE +#endif + +#include "btf.h" +#include "bpf.h" +#include "libbpf.h" +#include "libbpf_internal.h" + +struct btf; + +struct btf_relocate { + struct btf *btf; + const struct btf *base_btf; + const struct btf *dist_base_btf; + unsigned int nr_base_types; + unsigned int nr_split_types; + unsigned int nr_dist_base_types; + int dist_str_len; + int base_str_len; + __u32 *id_map; + __u32 *str_map; +}; + +/* Set temporarily in relocation id_map if distilled base struct/union is + * embedded in a split BTF struct/union; in such a case, size information must + * match between distilled base BTF and base BTF representation of type. + */ +#define BTF_IS_EMBEDDED ((__u32)-1) + +/* triple used in sorting/searching distilled base BTF. */ +struct btf_name_info { + const char *name; + /* set when search requires a size match */ + int needs_size:1, + size:31; + __u32 id; +}; + +static int btf_relocate_rewrite_type_id(struct btf_relocate *r, __u32 i) +{ + struct btf_type *t = btf_type_by_id(r->btf, i); + struct btf_field_iter it; + __u32 *id; + int err; + + err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_IDS); + if (err) + return err; + + while ((id = btf_field_iter_next(&it))) + *id = r->id_map[*id]; + return 0; +} + +/* Simple string comparison used for sorting within BTF, since all distilled + * types are named. If strings match, and size is non-zero for both elements + * fall back to using size for ordering. + */ +static int cmp_btf_name_size(const void *n1, const void *n2) +{ + const struct btf_name_info *ni1 = n1; + const struct btf_name_info *ni2 = n2; + int name_diff = strcmp(ni1->name, ni2->name); + + if (!name_diff && ni1->needs_size && ni2->needs_size) + return ni2->size - ni1->size; + return name_diff; +} + +/* Binary search with a small twist; find leftmost element that matches + * so that we can then iterate through all exact matches. So for example + * searching { "a", "bb", "bb", "c" } we would always match on the + * leftmost "bb". + */ +static struct btf_name_info *search_btf_name_size(struct btf_name_info *key, + struct btf_name_info *vals, + int nelems) +{ + struct btf_name_info *ret = NULL; + int high = nelems - 1; + int low = 0; + + while (low <= high) { + int mid = (low + high)/2; + struct btf_name_info *val = &vals[mid]; + int diff = cmp_btf_name_size(key, val); + + if (diff == 0) + ret = val; + /* even if found, keep searching for leftmost match */ + if (diff <= 0) + high = mid - 1; + else + low = mid + 1; + } + return ret; +} + +/* If a member of a split BTF struct/union refers to a base BTF + * struct/union, mark that struct/union id temporarily in the id_map + * with BTF_IS_EMBEDDED. Members can be const/restrict/volatile/typedef + * reference types, but if a pointer is encountered, the type is no longer + * considered embedded. + */ +static int btf_mark_embedded_composite_type_ids(struct btf_relocate *r, __u32 i) +{ + struct btf_type *t = btf_type_by_id(r->btf, i); + struct btf_field_iter it; + __u32 *id; + int err; + + if (!btf_is_composite(t)) + return 0; + + err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_IDS); + if (err) + return err; + + while ((id = btf_field_iter_next(&it))) { + __u32 next_id = *id; + + while (next_id) { + t = btf_type_by_id(r->btf, next_id); + switch (btf_kind(t)) { + case BTF_KIND_CONST: + case BTF_KIND_RESTRICT: + case BTF_KIND_VOLATILE: + case BTF_KIND_TYPEDEF: + case BTF_KIND_TYPE_TAG: + next_id = t->type; + break; + case BTF_KIND_ARRAY: { + struct btf_array *a = btf_array(t); + + next_id = a->type; + break; + } + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + if (next_id < r->nr_dist_base_types) + r->id_map[next_id] = BTF_IS_EMBEDDED; + next_id = 0; + break; + default: + next_id = 0; + break; + } + } + } + + return 0; +} + +/* Build a map from distilled base BTF ids to base BTF ids. To do so, iterate + * through base BTF looking up distilled type (using binary search) equivalents. + */ +static int btf_relocate_map_distilled_base(struct btf_relocate *r) +{ + struct btf_name_info *dist_base_info_sorted, *dist_base_info_sorted_end; + struct btf_type *base_t, *dist_t; + __u8 *base_name_cnt = NULL; + int err = 0; + __u32 id; + + /* generate a sort index array of name/type ids sorted by name for + * distilled base BTF to speed name-based lookups. + */ + dist_base_info_sorted = calloc(r->nr_dist_base_types, sizeof(*dist_base_info_sorted)); + if (!dist_base_info_sorted) { + err = -ENOMEM; + goto done; + } + dist_base_info_sorted_end = dist_base_info_sorted + r->nr_dist_base_types; + for (id = 0; id < r->nr_dist_base_types; id++) { + dist_t = btf_type_by_id(r->dist_base_btf, id); + dist_base_info_sorted[id].name = btf__name_by_offset(r->dist_base_btf, + dist_t->name_off); + dist_base_info_sorted[id].id = id; + dist_base_info_sorted[id].size = dist_t->size; + dist_base_info_sorted[id].needs_size = true; + } + qsort(dist_base_info_sorted, r->nr_dist_base_types, sizeof(*dist_base_info_sorted), + cmp_btf_name_size); + + /* Mark distilled base struct/union members of split BTF structs/unions + * in id_map with BTF_IS_EMBEDDED; this signals that these types + * need to match both name and size, otherwise embeddding the base + * struct/union in the split type is invalid. + */ + for (id = r->nr_dist_base_types; id < r->nr_split_types; id++) { + err = btf_mark_embedded_composite_type_ids(r, id); + if (err) + goto done; + } + + /* Collect name counts for composite types in base BTF. If multiple + * instances of a struct/union of the same name exist, we need to use + * size to determine which to map to since name alone is ambiguous. + */ + base_name_cnt = calloc(r->base_str_len, sizeof(*base_name_cnt)); + if (!base_name_cnt) { + err = -ENOMEM; + goto done; + } + for (id = 1; id < r->nr_base_types; id++) { + base_t = btf_type_by_id(r->base_btf, id); + if (!btf_is_composite(base_t) || !base_t->name_off) + continue; + if (base_name_cnt[base_t->name_off] < 255) + base_name_cnt[base_t->name_off]++; + } + + /* Now search base BTF for matching distilled base BTF types. */ + for (id = 1; id < r->nr_base_types; id++) { + struct btf_name_info *dist_name_info, *dist_name_info_next = NULL; + struct btf_name_info base_name_info = {}; + int dist_kind, base_kind; + + base_t = btf_type_by_id(r->base_btf, id); + /* distilled base consists of named types only. */ + if (!base_t->name_off) + continue; + base_kind = btf_kind(base_t); + base_name_info.id = id; + base_name_info.name = btf__name_by_offset(r->base_btf, base_t->name_off); + switch (base_kind) { + case BTF_KIND_INT: + case BTF_KIND_FLOAT: + case BTF_KIND_ENUM: + case BTF_KIND_ENUM64: + /* These types should match both name and size */ + base_name_info.needs_size = true; + base_name_info.size = base_t->size; + break; + case BTF_KIND_FWD: + /* No size considerations for fwds. */ + break; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + /* Size only needs to be used for struct/union if there + * are multiple types in base BTF with the same name. + * If there are multiple _distilled_ types with the same + * name (a very unlikely scenario), that doesn't matter + * unless corresponding _base_ types to match them are + * missing. + */ + base_name_info.needs_size = base_name_cnt[base_t->name_off] > 1; + base_name_info.size = base_t->size; + break; + default: + continue; + } + /* iterate over all matching distilled base types */ + for (dist_name_info = search_btf_name_size(&base_name_info, dist_base_info_sorted, + r->nr_dist_base_types); + dist_name_info != NULL; dist_name_info = dist_name_info_next) { + /* Are there more distilled matches to process after + * this one? + */ + dist_name_info_next = dist_name_info + 1; + if (dist_name_info_next >= dist_base_info_sorted_end || + cmp_btf_name_size(&base_name_info, dist_name_info_next)) + dist_name_info_next = NULL; + + if (!dist_name_info->id || dist_name_info->id > r->nr_dist_base_types) { + pr_warn("base BTF id [%d] maps to invalid distilled base BTF id [%d]\n", + id, dist_name_info->id); + err = -EINVAL; + goto done; + } + dist_t = btf_type_by_id(r->dist_base_btf, dist_name_info->id); + dist_kind = btf_kind(dist_t); + + /* Validate that the found distilled type is compatible. + * Do not error out on mismatch as another match may + * occur for an identically-named type. + */ + switch (dist_kind) { + case BTF_KIND_FWD: + switch (base_kind) { + case BTF_KIND_FWD: + if (btf_kflag(dist_t) != btf_kflag(base_t)) + continue; + break; + case BTF_KIND_STRUCT: + if (btf_kflag(base_t)) + continue; + break; + case BTF_KIND_UNION: + if (!btf_kflag(base_t)) + continue; + break; + default: + continue; + } + break; + case BTF_KIND_INT: + if (dist_kind != base_kind || + btf_int_encoding(base_t) != btf_int_encoding(dist_t)) + continue; + break; + case BTF_KIND_FLOAT: + if (dist_kind != base_kind) + continue; + break; + case BTF_KIND_ENUM: + /* ENUM and ENUM64 are encoded as sized ENUM in + * distilled base BTF. + */ + if (base_kind != dist_kind && base_kind != BTF_KIND_ENUM64) + continue; + break; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + /* size verification is required for embedded + * struct/unions. + */ + if (r->id_map[dist_name_info->id] == BTF_IS_EMBEDDED && + base_t->size != dist_t->size) + continue; + break; + default: + continue; + } + if (r->id_map[dist_name_info->id] && + r->id_map[dist_name_info->id] != BTF_IS_EMBEDDED) { + /* we already have a match; this tells us that + * multiple base types of the same name + * have the same size, since for cases where + * multiple types have the same name we match + * on name and size. In this case, we have + * no way of determining which to relocate + * to in base BTF, so error out. + */ + pr_warn("distilled base BTF type '%s' [%u], size %u has multiple candidates of the same size (ids [%u, %u]) in base BTF\n", + base_name_info.name, dist_name_info->id, + base_t->size, id, r->id_map[dist_name_info->id]); + err = -EINVAL; + goto done; + } + /* map id and name */ + r->id_map[dist_name_info->id] = id; + r->str_map[dist_t->name_off] = base_t->name_off; + } + } + /* ensure all distilled BTF ids now have a mapping... */ + for (id = 1; id < r->nr_dist_base_types; id++) { + const char *name; + + if (r->id_map[id] && r->id_map[id] != BTF_IS_EMBEDDED) + continue; + dist_t = btf_type_by_id(r->dist_base_btf, id); + name = btf__name_by_offset(r->dist_base_btf, dist_t->name_off); + pr_warn("distilled base BTF type '%s' [%d] is not mapped to base BTF id\n", + name, id); + err = -EINVAL; + break; + } +done: + free(base_name_cnt); + free(dist_base_info_sorted); + return err; +} + +/* distilled base should only have named int/float/enum/fwd/struct/union types. */ +static int btf_relocate_validate_distilled_base(struct btf_relocate *r) +{ + unsigned int i; + + for (i = 1; i < r->nr_dist_base_types; i++) { + struct btf_type *t = btf_type_by_id(r->dist_base_btf, i); + int kind = btf_kind(t); + + switch (kind) { + case BTF_KIND_INT: + case BTF_KIND_FLOAT: + case BTF_KIND_ENUM: + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + case BTF_KIND_FWD: + if (t->name_off) + break; + pr_warn("type [%d], kind [%d] is invalid for distilled base BTF; it is anonymous\n", + i, kind); + return -EINVAL; + default: + pr_warn("type [%d] in distilled based BTF has unexpected kind [%d]\n", + i, kind); + return -EINVAL; + } + } + return 0; +} + +static int btf_relocate_rewrite_strs(struct btf_relocate *r, __u32 i) +{ + struct btf_type *t = btf_type_by_id(r->btf, i); + struct btf_field_iter it; + __u32 *str_off; + int off, err; + + err = btf_field_iter_init(&it, t, BTF_FIELD_ITER_STRS); + if (err) + return err; + + while ((str_off = btf_field_iter_next(&it))) { + if (!*str_off) + continue; + if (*str_off >= r->dist_str_len) { + *str_off += r->base_str_len - r->dist_str_len; + } else { + off = r->str_map[*str_off]; + if (!off) { + pr_warn("string '%s' [offset %u] is not mapped to base BTF", + btf__str_by_offset(r->btf, off), *str_off); + return -ENOENT; + } + *str_off = off; + } + } + return 0; +} + +/* If successful, output of relocation is updated BTF with base BTF pointing + * at base_btf, and type ids, strings adjusted accordingly. + */ +int btf_relocate(struct btf *btf, const struct btf *base_btf, __u32 **id_map) +{ + unsigned int nr_types = btf__type_cnt(btf); + const struct btf_header *dist_base_hdr; + const struct btf_header *base_hdr; + struct btf_relocate r = {}; + int err = 0; + __u32 id, i; + + r.dist_base_btf = btf__base_btf(btf); + if (!base_btf || r.dist_base_btf == base_btf) + return -EINVAL; + + r.nr_dist_base_types = btf__type_cnt(r.dist_base_btf); + r.nr_base_types = btf__type_cnt(base_btf); + r.nr_split_types = nr_types - r.nr_dist_base_types; + r.btf = btf; + r.base_btf = base_btf; + + r.id_map = calloc(nr_types, sizeof(*r.id_map)); + r.str_map = calloc(btf_header(r.dist_base_btf)->str_len, sizeof(*r.str_map)); + dist_base_hdr = btf_header(r.dist_base_btf); + base_hdr = btf_header(r.base_btf); + r.dist_str_len = dist_base_hdr->str_len; + r.base_str_len = base_hdr->str_len; + if (!r.id_map || !r.str_map) { + err = -ENOMEM; + goto err_out; + } + + err = btf_relocate_validate_distilled_base(&r); + if (err) + goto err_out; + + /* Split BTF ids need to be adjusted as base and distilled base + * have different numbers of types, changing the start id of split + * BTF. + */ + for (id = r.nr_dist_base_types; id < nr_types; id++) + r.id_map[id] = id + r.nr_base_types - r.nr_dist_base_types; + + /* Build a map from distilled base ids to actual base BTF ids; it is used + * to update split BTF id references. Also build a str_map mapping from + * distilled base BTF names to base BTF names. + */ + err = btf_relocate_map_distilled_base(&r); + if (err) + goto err_out; + + /* Next, rewrite type ids in split BTF, replacing split ids with updated + * ids based on number of types in base BTF, and base ids with + * relocated ids from base_btf. + */ + for (i = 0, id = r.nr_dist_base_types; i < r.nr_split_types; i++, id++) { + err = btf_relocate_rewrite_type_id(&r, id); + if (err) + goto err_out; + } + /* String offsets now need to be updated using the str_map. */ + for (i = 0; i < r.nr_split_types; i++) { + err = btf_relocate_rewrite_strs(&r, i + r.nr_dist_base_types); + if (err) + goto err_out; + } + /* Finally reset base BTF to be base_btf */ + btf_set_base_btf(btf, base_btf); + + if (id_map) { + *id_map = r.id_map; + r.id_map = NULL; + } +err_out: + free(r.id_map); + free(r.str_map); + return err; +} diff --git a/src/libbpf.map b/src/libbpf.map index 175d153..8f0d9ea 100644 --- a/src/libbpf.map +++ b/src/libbpf.map @@ -420,6 +420,7 @@ LIBBPF_1.4.0 { LIBBPF_1.5.0 { global: btf__distill_base; + btf__relocate; bpf_map__autoattach; bpf_map__set_autoattach; bpf_program__attach_sockmap; diff --git a/src/libbpf_internal.h b/src/libbpf_internal.h index e2f0660..408df59 100644 --- a/src/libbpf_internal.h +++ b/src/libbpf_internal.h @@ -234,6 +234,9 @@ struct btf_type; struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id); const char *btf_kind_str(const struct btf_type *t); const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id); +const struct btf_header *btf_header(const struct btf *btf); +void btf_set_base_btf(struct btf *btf, const struct btf *base_btf); +int btf_relocate(struct btf *btf, const struct btf *base_btf, __u32 **id_map); static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t) { From 4bc5a64933cb6c5566df15958a8df5a3eedbcc79 Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Thu, 13 Jun 2024 10:50:10 +0100 Subject: [PATCH 11/26] libbpf: Make btf_parse_elf process .BTF.base transparently Update btf_parse_elf() to check if .BTF.base section is present. The logic is as follows: if .BTF.base section exists: distilled_base := btf_new(.BTF.base) if distilled_base: btf := btf_new(.BTF, .base_btf=distilled_base) if base_btf: btf_relocate(btf, base_btf) else: btf := btf_new(.BTF) return btf In other words: - if .BTF.base section exists, load BTF from it and use it as a base for .BTF load; - if base_btf is specified and .BTF.base section exist, relocate newly loaded .BTF against base_btf. Signed-off-by: Eduard Zingerman Signed-off-by: Alan Maguire Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20240613095014.357981-6-alan.maguire@oracle.com --- src/btf.c | 186 +++++++++++++++++++++++++++++++++++------------------- src/btf.h | 1 + 2 files changed, 122 insertions(+), 65 deletions(-) diff --git a/src/btf.c b/src/btf.c index 5e20354..ef1b2f5 100644 --- a/src/btf.c +++ b/src/btf.c @@ -116,6 +116,9 @@ struct btf { /* whether strings are already deduplicated */ bool strs_deduped; + /* whether base_btf should be freed in btf_free for this instance */ + bool owns_base; + /* BTF object FD, if loaded into kernel */ int fd; @@ -969,6 +972,8 @@ void btf__free(struct btf *btf) free(btf->raw_data); free(btf->raw_data_swapped); free(btf->type_offs); + if (btf->owns_base) + btf__free(btf->base_btf); free(btf); } @@ -1084,16 +1089,86 @@ struct btf *btf__new_split(const void *data, __u32 size, struct btf *base_btf) return libbpf_ptr(btf_new(data, size, base_btf)); } +struct btf_elf_secs { + Elf_Data *btf_data; + Elf_Data *btf_ext_data; + Elf_Data *btf_base_data; +}; + +static int btf_find_elf_sections(Elf *elf, const char *path, struct btf_elf_secs *secs) +{ + Elf_Scn *scn = NULL; + Elf_Data *data; + GElf_Ehdr ehdr; + size_t shstrndx; + int idx = 0; + + if (!gelf_getehdr(elf, &ehdr)) { + pr_warn("failed to get EHDR from %s\n", path); + goto err; + } + + if (elf_getshdrstrndx(elf, &shstrndx)) { + pr_warn("failed to get section names section index for %s\n", + path); + goto err; + } + + if (!elf_rawdata(elf_getscn(elf, shstrndx), NULL)) { + pr_warn("failed to get e_shstrndx from %s\n", path); + goto err; + } + + while ((scn = elf_nextscn(elf, scn)) != NULL) { + Elf_Data **field; + GElf_Shdr sh; + char *name; + + idx++; + if (gelf_getshdr(scn, &sh) != &sh) { + pr_warn("failed to get section(%d) header from %s\n", + idx, path); + goto err; + } + name = elf_strptr(elf, shstrndx, sh.sh_name); + if (!name) { + pr_warn("failed to get section(%d) name from %s\n", + idx, path); + goto err; + } + + if (strcmp(name, BTF_ELF_SEC) == 0) + field = &secs->btf_data; + else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) + field = &secs->btf_ext_data; + else if (strcmp(name, BTF_BASE_ELF_SEC) == 0) + field = &secs->btf_base_data; + else + continue; + + data = elf_getdata(scn, 0); + if (!data) { + pr_warn("failed to get section(%d, %s) data from %s\n", + idx, name, path); + goto err; + } + *field = data; + } + + return 0; + +err: + return -LIBBPF_ERRNO__FORMAT; +} + static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, struct btf_ext **btf_ext) { - Elf_Data *btf_data = NULL, *btf_ext_data = NULL; - int err = 0, fd = -1, idx = 0; + struct btf_elf_secs secs = {}; + struct btf *dist_base_btf = NULL; struct btf *btf = NULL; - Elf_Scn *scn = NULL; + int err = 0, fd = -1; Elf *elf = NULL; - GElf_Ehdr ehdr; - size_t shstrndx; if (elf_version(EV_CURRENT) == EV_NONE) { pr_warn("failed to init libelf for %s\n", path); @@ -1107,73 +1182,48 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, return ERR_PTR(err); } - err = -LIBBPF_ERRNO__FORMAT; - elf = elf_begin(fd, ELF_C_READ, NULL); if (!elf) { pr_warn("failed to open %s as ELF file\n", path); goto done; } - if (!gelf_getehdr(elf, &ehdr)) { - pr_warn("failed to get EHDR from %s\n", path); + + err = btf_find_elf_sections(elf, path, &secs); + if (err) goto done; - } - if (elf_getshdrstrndx(elf, &shstrndx)) { - pr_warn("failed to get section names section index for %s\n", - path); - goto done; - } - - if (!elf_rawdata(elf_getscn(elf, shstrndx), NULL)) { - pr_warn("failed to get e_shstrndx from %s\n", path); - goto done; - } - - while ((scn = elf_nextscn(elf, scn)) != NULL) { - GElf_Shdr sh; - char *name; - - idx++; - if (gelf_getshdr(scn, &sh) != &sh) { - pr_warn("failed to get section(%d) header from %s\n", - idx, path); - goto done; - } - name = elf_strptr(elf, shstrndx, sh.sh_name); - if (!name) { - pr_warn("failed to get section(%d) name from %s\n", - idx, path); - goto done; - } - if (strcmp(name, BTF_ELF_SEC) == 0) { - btf_data = elf_getdata(scn, 0); - if (!btf_data) { - pr_warn("failed to get section(%d, %s) data from %s\n", - idx, name, path); - goto done; - } - continue; - } else if (btf_ext && strcmp(name, BTF_EXT_ELF_SEC) == 0) { - btf_ext_data = elf_getdata(scn, 0); - if (!btf_ext_data) { - pr_warn("failed to get section(%d, %s) data from %s\n", - idx, name, path); - goto done; - } - continue; - } - } - - if (!btf_data) { + if (!secs.btf_data) { pr_warn("failed to find '%s' ELF section in %s\n", BTF_ELF_SEC, path); err = -ENODATA; goto done; } - btf = btf_new(btf_data->d_buf, btf_data->d_size, base_btf); - err = libbpf_get_error(btf); - if (err) + + if (secs.btf_base_data) { + dist_base_btf = btf_new(secs.btf_base_data->d_buf, secs.btf_base_data->d_size, + NULL); + if (IS_ERR(dist_base_btf)) { + err = PTR_ERR(dist_base_btf); + dist_base_btf = NULL; + goto done; + } + } + + btf = btf_new(secs.btf_data->d_buf, secs.btf_data->d_size, + dist_base_btf ?: base_btf); + if (IS_ERR(btf)) { + err = PTR_ERR(btf); goto done; + } + if (dist_base_btf && base_btf) { + err = btf__relocate(btf, base_btf); + if (err) + goto done; + btf__free(dist_base_btf); + dist_base_btf = NULL; + } + + if (dist_base_btf) + btf->owns_base = true; switch (gelf_getclass(elf)) { case ELFCLASS32: @@ -1187,11 +1237,12 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, break; } - if (btf_ext && btf_ext_data) { - *btf_ext = btf_ext__new(btf_ext_data->d_buf, btf_ext_data->d_size); - err = libbpf_get_error(*btf_ext); - if (err) + if (btf_ext && secs.btf_ext_data) { + *btf_ext = btf_ext__new(secs.btf_ext_data->d_buf, secs.btf_ext_data->d_size); + if (IS_ERR(*btf_ext)) { + err = PTR_ERR(*btf_ext); goto done; + } } else if (btf_ext) { *btf_ext = NULL; } @@ -1205,6 +1256,7 @@ done: if (btf_ext) btf_ext__free(*btf_ext); + btf__free(dist_base_btf); btf__free(btf); return ERR_PTR(err); @@ -5598,5 +5650,9 @@ void btf_set_base_btf(struct btf *btf, const struct btf *base_btf) int btf__relocate(struct btf *btf, const struct btf *base_btf) { - return libbpf_err(btf_relocate(btf, base_btf, NULL)); + int err = btf_relocate(btf, base_btf, NULL); + + if (!err) + btf->owns_base = false; + return libbpf_err(err); } diff --git a/src/btf.h b/src/btf.h index 8a93120..b68d216 100644 --- a/src/btf.h +++ b/src/btf.h @@ -18,6 +18,7 @@ extern "C" { #define BTF_ELF_SEC ".BTF" #define BTF_EXT_ELF_SEC ".BTF.ext" +#define BTF_BASE_ELF_SEC ".BTF.base" #define MAPS_ELF_SEC ".maps" struct btf; From 88a0787335dc5874f98908e049b90b78e8bba2d0 Mon Sep 17 00:00:00 2001 From: Donglin Peng Date: Wed, 19 Jun 2024 05:23:55 -0700 Subject: [PATCH 12/26] libbpf: Checking the btf_type kind when fixing variable offsets I encountered an issue when building the test_progs from the repository [1]: $ pwd /work/Qemu/x86_64/linux-6.10-rc2/tools/testing/selftests/bpf/ $ make test_progs V=1 [...] ./tools/sbin/bpftool gen object ./ip_check_defrag.bpf.linked2.o ./ip_check_defrag.bpf.linked1.o libbpf: failed to find symbol for variable 'bpf_dynptr_slice' in section '.ksyms' Error: failed to link './ip_check_defrag.bpf.linked1.o': No such file or directory (2) [...] Upon investigation, I discovered that the btf_types referenced in the '.ksyms' section had a kind of BTF_KIND_FUNC instead of BTF_KIND_VAR: $ bpftool btf dump file ./ip_check_defrag.bpf.linked1.o [...] [2] DATASEC '.ksyms' size=0 vlen=2 type_id=16 offset=0 size=0 (FUNC 'bpf_dynptr_from_skb') type_id=17 offset=0 size=0 (FUNC 'bpf_dynptr_slice') [...] [16] FUNC 'bpf_dynptr_from_skb' type_id=82 linkage=extern [17] FUNC 'bpf_dynptr_slice' type_id=85 linkage=extern [...] For a detailed analysis, please refer to [2]. We can add a kind checking to fix the issue. [1] https://github.com/eddyz87/bpf/tree/binsort-btf-dedup [2] https://lore.kernel.org/all/0c0ef20c-c05e-4db9-bad7-2cbc0d6dfae7@oracle.com/ Fixes: 8fd27bf69b86 ("libbpf: Add BPF static linker BTF and BTF.ext support") Signed-off-by: Donglin Peng Signed-off-by: Daniel Borkmann Reviewed-by: Alan Maguire Acked-by: Eduard Zingerman Link: https://lore.kernel.org/bpf/20240619122355.426405-1-dolinux.peng@gmail.com --- src/linker.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/src/linker.c b/src/linker.c index fa11a67..9cd3d41 100644 --- a/src/linker.c +++ b/src/linker.c @@ -2227,10 +2227,17 @@ static int linker_fixup_btf(struct src_obj *obj) vi = btf_var_secinfos(t); for (j = 0, m = btf_vlen(t); j < m; j++, vi++) { const struct btf_type *vt = btf__type_by_id(obj->btf, vi->type); - const char *var_name = btf__str_by_offset(obj->btf, vt->name_off); - int var_linkage = btf_var(vt)->linkage; + const char *var_name; + int var_linkage; Elf64_Sym *sym; + /* could be a variable or function */ + if (!btf_is_var(vt)) + continue; + + var_name = btf__str_by_offset(obj->btf, vt->name_off); + var_linkage = btf_var(vt)->linkage; + /* no need to patch up static or extern vars */ if (var_linkage != BTF_VAR_GLOBAL_ALLOCATED) continue; From bc021a8b423b24f8bdabecf52d3866f62743e13e Mon Sep 17 00:00:00 2001 From: Alan Maguire Date: Thu, 20 Jun 2024 10:17:28 +0100 Subject: [PATCH 13/26] libbpf: BTF relocation followup fixing naming, loop logic Use less verbose names in BTF relocation code and fix off-by-one error and typo in btf_relocate.c. Simplify loop over matching distilled types, moving from assigning a _next value in loop body to moving match check conditions into the guard. Suggested-by: Andrii Nakryiko Signed-off-by: Alan Maguire Signed-off-by: Andrii Nakryiko Acked-by: Eduard Zingerman Link: https://lore.kernel.org/bpf/20240620091733.1967885-2-alan.maguire@oracle.com --- src/btf_relocate.c | 72 ++++++++++++++++++++-------------------------- 1 file changed, 31 insertions(+), 41 deletions(-) diff --git a/src/btf_relocate.c b/src/btf_relocate.c index eabb875..23a41fb 100644 --- a/src/btf_relocate.c +++ b/src/btf_relocate.c @@ -160,7 +160,7 @@ static int btf_mark_embedded_composite_type_ids(struct btf_relocate *r, __u32 i) */ static int btf_relocate_map_distilled_base(struct btf_relocate *r) { - struct btf_name_info *dist_base_info_sorted, *dist_base_info_sorted_end; + struct btf_name_info *info, *info_end; struct btf_type *base_t, *dist_t; __u8 *base_name_cnt = NULL; int err = 0; @@ -169,26 +169,24 @@ static int btf_relocate_map_distilled_base(struct btf_relocate *r) /* generate a sort index array of name/type ids sorted by name for * distilled base BTF to speed name-based lookups. */ - dist_base_info_sorted = calloc(r->nr_dist_base_types, sizeof(*dist_base_info_sorted)); - if (!dist_base_info_sorted) { + info = calloc(r->nr_dist_base_types, sizeof(*info)); + if (!info) { err = -ENOMEM; goto done; } - dist_base_info_sorted_end = dist_base_info_sorted + r->nr_dist_base_types; + info_end = info + r->nr_dist_base_types; for (id = 0; id < r->nr_dist_base_types; id++) { dist_t = btf_type_by_id(r->dist_base_btf, id); - dist_base_info_sorted[id].name = btf__name_by_offset(r->dist_base_btf, - dist_t->name_off); - dist_base_info_sorted[id].id = id; - dist_base_info_sorted[id].size = dist_t->size; - dist_base_info_sorted[id].needs_size = true; + info[id].name = btf__name_by_offset(r->dist_base_btf, dist_t->name_off); + info[id].id = id; + info[id].size = dist_t->size; + info[id].needs_size = true; } - qsort(dist_base_info_sorted, r->nr_dist_base_types, sizeof(*dist_base_info_sorted), - cmp_btf_name_size); + qsort(info, r->nr_dist_base_types, sizeof(*info), cmp_btf_name_size); /* Mark distilled base struct/union members of split BTF structs/unions * in id_map with BTF_IS_EMBEDDED; this signals that these types - * need to match both name and size, otherwise embeddding the base + * need to match both name and size, otherwise embedding the base * struct/union in the split type is invalid. */ for (id = r->nr_dist_base_types; id < r->nr_split_types; id++) { @@ -216,8 +214,7 @@ static int btf_relocate_map_distilled_base(struct btf_relocate *r) /* Now search base BTF for matching distilled base BTF types. */ for (id = 1; id < r->nr_base_types; id++) { - struct btf_name_info *dist_name_info, *dist_name_info_next = NULL; - struct btf_name_info base_name_info = {}; + struct btf_name_info *dist_info, base_info = {}; int dist_kind, base_kind; base_t = btf_type_by_id(r->base_btf, id); @@ -225,16 +222,16 @@ static int btf_relocate_map_distilled_base(struct btf_relocate *r) if (!base_t->name_off) continue; base_kind = btf_kind(base_t); - base_name_info.id = id; - base_name_info.name = btf__name_by_offset(r->base_btf, base_t->name_off); + base_info.id = id; + base_info.name = btf__name_by_offset(r->base_btf, base_t->name_off); switch (base_kind) { case BTF_KIND_INT: case BTF_KIND_FLOAT: case BTF_KIND_ENUM: case BTF_KIND_ENUM64: /* These types should match both name and size */ - base_name_info.needs_size = true; - base_name_info.size = base_t->size; + base_info.needs_size = true; + base_info.size = base_t->size; break; case BTF_KIND_FWD: /* No size considerations for fwds. */ @@ -248,31 +245,24 @@ static int btf_relocate_map_distilled_base(struct btf_relocate *r) * unless corresponding _base_ types to match them are * missing. */ - base_name_info.needs_size = base_name_cnt[base_t->name_off] > 1; - base_name_info.size = base_t->size; + base_info.needs_size = base_name_cnt[base_t->name_off] > 1; + base_info.size = base_t->size; break; default: continue; } /* iterate over all matching distilled base types */ - for (dist_name_info = search_btf_name_size(&base_name_info, dist_base_info_sorted, - r->nr_dist_base_types); - dist_name_info != NULL; dist_name_info = dist_name_info_next) { - /* Are there more distilled matches to process after - * this one? - */ - dist_name_info_next = dist_name_info + 1; - if (dist_name_info_next >= dist_base_info_sorted_end || - cmp_btf_name_size(&base_name_info, dist_name_info_next)) - dist_name_info_next = NULL; - - if (!dist_name_info->id || dist_name_info->id > r->nr_dist_base_types) { + for (dist_info = search_btf_name_size(&base_info, info, r->nr_dist_base_types); + dist_info != NULL && dist_info < info_end && + cmp_btf_name_size(&base_info, dist_info) == 0; + dist_info++) { + if (!dist_info->id || dist_info->id >= r->nr_dist_base_types) { pr_warn("base BTF id [%d] maps to invalid distilled base BTF id [%d]\n", - id, dist_name_info->id); + id, dist_info->id); err = -EINVAL; goto done; } - dist_t = btf_type_by_id(r->dist_base_btf, dist_name_info->id); + dist_t = btf_type_by_id(r->dist_base_btf, dist_info->id); dist_kind = btf_kind(dist_t); /* Validate that the found distilled type is compatible. @@ -319,15 +309,15 @@ static int btf_relocate_map_distilled_base(struct btf_relocate *r) /* size verification is required for embedded * struct/unions. */ - if (r->id_map[dist_name_info->id] == BTF_IS_EMBEDDED && + if (r->id_map[dist_info->id] == BTF_IS_EMBEDDED && base_t->size != dist_t->size) continue; break; default: continue; } - if (r->id_map[dist_name_info->id] && - r->id_map[dist_name_info->id] != BTF_IS_EMBEDDED) { + if (r->id_map[dist_info->id] && + r->id_map[dist_info->id] != BTF_IS_EMBEDDED) { /* we already have a match; this tells us that * multiple base types of the same name * have the same size, since for cases where @@ -337,13 +327,13 @@ static int btf_relocate_map_distilled_base(struct btf_relocate *r) * to in base BTF, so error out. */ pr_warn("distilled base BTF type '%s' [%u], size %u has multiple candidates of the same size (ids [%u, %u]) in base BTF\n", - base_name_info.name, dist_name_info->id, - base_t->size, id, r->id_map[dist_name_info->id]); + base_info.name, dist_info->id, + base_t->size, id, r->id_map[dist_info->id]); err = -EINVAL; goto done; } /* map id and name */ - r->id_map[dist_name_info->id] = id; + r->id_map[dist_info->id] = id; r->str_map[dist_t->name_off] = base_t->name_off; } } @@ -362,7 +352,7 @@ static int btf_relocate_map_distilled_base(struct btf_relocate *r) } done: free(base_name_cnt); - free(dist_base_info_sorted); + free(info); return err; } From 4ffb92e204fae42987bbf275d2de07282ddfaf6f Mon Sep 17 00:00:00 2001 From: Alan Maguire Date: Thu, 20 Jun 2024 10:17:30 +0100 Subject: [PATCH 14/26] libbpf: Split field iter code into its own file kernel This will allow it to be shared with the kernel. No functional change. Suggested-by: Andrii Nakryiko Signed-off-by: Alan Maguire Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20240620091733.1967885-4-alan.maguire@oracle.com --- src/btf.c | 162 ----------------------------------------------- src/btf_iter.c | 169 +++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 169 insertions(+), 162 deletions(-) create mode 100644 src/btf_iter.c diff --git a/src/btf.c b/src/btf.c index ef1b2f5..0c0f60c 100644 --- a/src/btf.c +++ b/src/btf.c @@ -5093,168 +5093,6 @@ struct btf *btf__load_module_btf(const char *module_name, struct btf *vmlinux_bt return btf__parse_split(path, vmlinux_btf); } -int btf_field_iter_init(struct btf_field_iter *it, struct btf_type *t, enum btf_field_iter_kind iter_kind) -{ - it->p = NULL; - it->m_idx = -1; - it->off_idx = 0; - it->vlen = 0; - - switch (iter_kind) { - case BTF_FIELD_ITER_IDS: - switch (btf_kind(t)) { - case BTF_KIND_UNKN: - case BTF_KIND_INT: - case BTF_KIND_FLOAT: - case BTF_KIND_ENUM: - case BTF_KIND_ENUM64: - it->desc = (struct btf_field_desc) {}; - break; - case BTF_KIND_FWD: - case BTF_KIND_CONST: - case BTF_KIND_VOLATILE: - case BTF_KIND_RESTRICT: - case BTF_KIND_PTR: - case BTF_KIND_TYPEDEF: - case BTF_KIND_FUNC: - case BTF_KIND_VAR: - case BTF_KIND_DECL_TAG: - case BTF_KIND_TYPE_TAG: - it->desc = (struct btf_field_desc) { 1, {offsetof(struct btf_type, type)} }; - break; - case BTF_KIND_ARRAY: - it->desc = (struct btf_field_desc) { - 2, {sizeof(struct btf_type) + offsetof(struct btf_array, type), - sizeof(struct btf_type) + offsetof(struct btf_array, index_type)} - }; - break; - case BTF_KIND_STRUCT: - case BTF_KIND_UNION: - it->desc = (struct btf_field_desc) { - 0, {}, - sizeof(struct btf_member), - 1, {offsetof(struct btf_member, type)} - }; - break; - case BTF_KIND_FUNC_PROTO: - it->desc = (struct btf_field_desc) { - 1, {offsetof(struct btf_type, type)}, - sizeof(struct btf_param), - 1, {offsetof(struct btf_param, type)} - }; - break; - case BTF_KIND_DATASEC: - it->desc = (struct btf_field_desc) { - 0, {}, - sizeof(struct btf_var_secinfo), - 1, {offsetof(struct btf_var_secinfo, type)} - }; - break; - default: - return -EINVAL; - } - break; - case BTF_FIELD_ITER_STRS: - switch (btf_kind(t)) { - case BTF_KIND_UNKN: - it->desc = (struct btf_field_desc) {}; - break; - case BTF_KIND_INT: - case BTF_KIND_FLOAT: - case BTF_KIND_FWD: - case BTF_KIND_ARRAY: - case BTF_KIND_CONST: - case BTF_KIND_VOLATILE: - case BTF_KIND_RESTRICT: - case BTF_KIND_PTR: - case BTF_KIND_TYPEDEF: - case BTF_KIND_FUNC: - case BTF_KIND_VAR: - case BTF_KIND_DECL_TAG: - case BTF_KIND_TYPE_TAG: - case BTF_KIND_DATASEC: - it->desc = (struct btf_field_desc) { - 1, {offsetof(struct btf_type, name_off)} - }; - break; - case BTF_KIND_ENUM: - it->desc = (struct btf_field_desc) { - 1, {offsetof(struct btf_type, name_off)}, - sizeof(struct btf_enum), - 1, {offsetof(struct btf_enum, name_off)} - }; - break; - case BTF_KIND_ENUM64: - it->desc = (struct btf_field_desc) { - 1, {offsetof(struct btf_type, name_off)}, - sizeof(struct btf_enum64), - 1, {offsetof(struct btf_enum64, name_off)} - }; - break; - case BTF_KIND_STRUCT: - case BTF_KIND_UNION: - it->desc = (struct btf_field_desc) { - 1, {offsetof(struct btf_type, name_off)}, - sizeof(struct btf_member), - 1, {offsetof(struct btf_member, name_off)} - }; - break; - case BTF_KIND_FUNC_PROTO: - it->desc = (struct btf_field_desc) { - 1, {offsetof(struct btf_type, name_off)}, - sizeof(struct btf_param), - 1, {offsetof(struct btf_param, name_off)} - }; - break; - default: - return -EINVAL; - } - break; - default: - return -EINVAL; - } - - if (it->desc.m_sz) - it->vlen = btf_vlen(t); - - it->p = t; - return 0; -} - -__u32 *btf_field_iter_next(struct btf_field_iter *it) -{ - if (!it->p) - return NULL; - - if (it->m_idx < 0) { - if (it->off_idx < it->desc.t_off_cnt) - return it->p + it->desc.t_offs[it->off_idx++]; - /* move to per-member iteration */ - it->m_idx = 0; - it->p += sizeof(struct btf_type); - it->off_idx = 0; - } - - /* if type doesn't have members, stop */ - if (it->desc.m_sz == 0) { - it->p = NULL; - return NULL; - } - - if (it->off_idx >= it->desc.m_off_cnt) { - /* exhausted this member's fields, go to the next member */ - it->m_idx++; - it->p += it->desc.m_sz; - it->off_idx = 0; - } - - if (it->m_idx < it->vlen) - return it->p + it->desc.m_offs[it->off_idx++]; - - it->p = NULL; - return NULL; -} - int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx) { const struct btf_ext_info *seg; diff --git a/src/btf_iter.c b/src/btf_iter.c new file mode 100644 index 0000000..c308aa6 --- /dev/null +++ b/src/btf_iter.c @@ -0,0 +1,169 @@ +// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) +/* Copyright (c) 2021 Facebook */ +/* Copyright (c) 2024, Oracle and/or its affiliates. */ + +#include "btf.h" +#include "libbpf_internal.h" + +int btf_field_iter_init(struct btf_field_iter *it, struct btf_type *t, + enum btf_field_iter_kind iter_kind) +{ + it->p = NULL; + it->m_idx = -1; + it->off_idx = 0; + it->vlen = 0; + + switch (iter_kind) { + case BTF_FIELD_ITER_IDS: + switch (btf_kind(t)) { + case BTF_KIND_UNKN: + case BTF_KIND_INT: + case BTF_KIND_FLOAT: + case BTF_KIND_ENUM: + case BTF_KIND_ENUM64: + it->desc = (struct btf_field_desc) {}; + break; + case BTF_KIND_FWD: + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_TYPEDEF: + case BTF_KIND_FUNC: + case BTF_KIND_VAR: + case BTF_KIND_DECL_TAG: + case BTF_KIND_TYPE_TAG: + it->desc = (struct btf_field_desc) { 1, {offsetof(struct btf_type, type)} }; + break; + case BTF_KIND_ARRAY: + it->desc = (struct btf_field_desc) { + 2, {sizeof(struct btf_type) + offsetof(struct btf_array, type), + sizeof(struct btf_type) + offsetof(struct btf_array, index_type)} + }; + break; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + it->desc = (struct btf_field_desc) { + 0, {}, + sizeof(struct btf_member), + 1, {offsetof(struct btf_member, type)} + }; + break; + case BTF_KIND_FUNC_PROTO: + it->desc = (struct btf_field_desc) { + 1, {offsetof(struct btf_type, type)}, + sizeof(struct btf_param), + 1, {offsetof(struct btf_param, type)} + }; + break; + case BTF_KIND_DATASEC: + it->desc = (struct btf_field_desc) { + 0, {}, + sizeof(struct btf_var_secinfo), + 1, {offsetof(struct btf_var_secinfo, type)} + }; + break; + default: + return -EINVAL; + } + break; + case BTF_FIELD_ITER_STRS: + switch (btf_kind(t)) { + case BTF_KIND_UNKN: + it->desc = (struct btf_field_desc) {}; + break; + case BTF_KIND_INT: + case BTF_KIND_FLOAT: + case BTF_KIND_FWD: + case BTF_KIND_ARRAY: + case BTF_KIND_CONST: + case BTF_KIND_VOLATILE: + case BTF_KIND_RESTRICT: + case BTF_KIND_PTR: + case BTF_KIND_TYPEDEF: + case BTF_KIND_FUNC: + case BTF_KIND_VAR: + case BTF_KIND_DECL_TAG: + case BTF_KIND_TYPE_TAG: + case BTF_KIND_DATASEC: + it->desc = (struct btf_field_desc) { + 1, {offsetof(struct btf_type, name_off)} + }; + break; + case BTF_KIND_ENUM: + it->desc = (struct btf_field_desc) { + 1, {offsetof(struct btf_type, name_off)}, + sizeof(struct btf_enum), + 1, {offsetof(struct btf_enum, name_off)} + }; + break; + case BTF_KIND_ENUM64: + it->desc = (struct btf_field_desc) { + 1, {offsetof(struct btf_type, name_off)}, + sizeof(struct btf_enum64), + 1, {offsetof(struct btf_enum64, name_off)} + }; + break; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + it->desc = (struct btf_field_desc) { + 1, {offsetof(struct btf_type, name_off)}, + sizeof(struct btf_member), + 1, {offsetof(struct btf_member, name_off)} + }; + break; + case BTF_KIND_FUNC_PROTO: + it->desc = (struct btf_field_desc) { + 1, {offsetof(struct btf_type, name_off)}, + sizeof(struct btf_param), + 1, {offsetof(struct btf_param, name_off)} + }; + break; + default: + return -EINVAL; + } + break; + default: + return -EINVAL; + } + + if (it->desc.m_sz) + it->vlen = btf_vlen(t); + + it->p = t; + return 0; +} + +__u32 *btf_field_iter_next(struct btf_field_iter *it) +{ + if (!it->p) + return NULL; + + if (it->m_idx < 0) { + if (it->off_idx < it->desc.t_off_cnt) + return it->p + it->desc.t_offs[it->off_idx++]; + /* move to per-member iteration */ + it->m_idx = 0; + it->p += sizeof(struct btf_type); + it->off_idx = 0; + } + + /* if type doesn't have members, stop */ + if (it->desc.m_sz == 0) { + it->p = NULL; + return NULL; + } + + if (it->off_idx >= it->desc.m_off_cnt) { + /* exhausted this member's fields, go to the next member */ + it->m_idx++; + it->p += it->desc.m_sz; + it->off_idx = 0; + } + + if (it->m_idx < it->vlen) + return it->p + it->desc.m_offs[it->off_idx++]; + + it->p = NULL; + return NULL; +} From 27f0169332813adeaa81599dc3c604a4043e7032 Mon Sep 17 00:00:00 2001 From: Alan Maguire Date: Thu, 20 Jun 2024 10:17:31 +0100 Subject: [PATCH 15/26] libbpf,bpf: Share BTF relocate-related code with kernel Share relocation implementation with the kernel. As part of this, we also need the type/string iteration functions so also share btf_iter.c file. Relocation code in kernel and userspace is identical save for the impementation of the reparenting of split BTF to the relocated base BTF and retrieval of the BTF header from "struct btf"; these small functions need separate user-space and kernel implementations for the separate "struct btf"s they operate upon. One other wrinkle on the kernel side is we have to map .BTF.ids in modules as they were generated with the type ids used at BTF encoding time. btf_relocate() optionally returns an array mapping from old BTF ids to relocated ids, so we use that to fix up these references where needed for kfuncs. Signed-off-by: Alan Maguire Signed-off-by: Andrii Nakryiko Acked-by: Eduard Zingerman Link: https://lore.kernel.org/bpf/20240620091733.1967885-5-alan.maguire@oracle.com --- src/btf_iter.c | 8 ++++++++ src/btf_relocate.c | 23 +++++++++++++++++++++++ 2 files changed, 31 insertions(+) diff --git a/src/btf_iter.c b/src/btf_iter.c index c308aa6..9a6c822 100644 --- a/src/btf_iter.c +++ b/src/btf_iter.c @@ -2,8 +2,16 @@ /* Copyright (c) 2021 Facebook */ /* Copyright (c) 2024, Oracle and/or its affiliates. */ +#ifdef __KERNEL__ +#include +#include + +#define btf_var_secinfos(t) (struct btf_var_secinfo *)btf_type_var_secinfo(t) + +#else #include "btf.h" #include "libbpf_internal.h" +#endif int btf_field_iter_init(struct btf_field_iter *it, struct btf_type *t, enum btf_field_iter_kind iter_kind) diff --git a/src/btf_relocate.c b/src/btf_relocate.c index 23a41fb..2281dbb 100644 --- a/src/btf_relocate.c +++ b/src/btf_relocate.c @@ -5,11 +5,34 @@ #define _GNU_SOURCE #endif +#ifdef __KERNEL__ +#include +#include +#include +#include +#include +#include + +#define btf_type_by_id (struct btf_type *)btf_type_by_id +#define btf__type_cnt btf_nr_types +#define btf__base_btf btf_base_btf +#define btf__name_by_offset btf_name_by_offset +#define btf__str_by_offset btf_str_by_offset +#define btf_kflag btf_type_kflag + +#define calloc(nmemb, sz) kvcalloc(nmemb, sz, GFP_KERNEL | __GFP_NOWARN) +#define free(ptr) kvfree(ptr) +#define qsort(base, num, sz, cmp) sort(base, num, sz, cmp, NULL) + +#else + #include "btf.h" #include "bpf.h" #include "libbpf.h" #include "libbpf_internal.h" +#endif /* __KERNEL__ */ + struct btf; struct btf_relocate { From 95c63a08f2d6cc4e4019ed3b9b63e79b41c4697f Mon Sep 17 00:00:00 2001 From: Antoine Tenart Date: Mon, 24 Jun 2024 11:09:07 +0200 Subject: [PATCH 16/26] libbpf: Skip base btf sanity checks When upgrading to libbpf 1.3 we noticed a big performance hit while loading programs using CORE on non base-BTF symbols. This was tracked down to the new BTF sanity check logic. The issue is the base BTF definitions are checked first for the base BTF and then again for every module BTF. Loading 5 dummy programs (using libbpf-rs) that are using CORE on a non-base BTF symbol on my system: - Before this fix: 3s. - With this fix: 0.1s. Fix this by only checking the types starting at the BTF start id. This should ensure the base BTF is still checked as expected but only once (btf->start_id == 1 when creating the base BTF), and then only additional types are checked for each module BTF. Fixes: 3903802bb99a ("libbpf: Add basic BTF sanity validation") Signed-off-by: Antoine Tenart Signed-off-by: Andrii Nakryiko Reviewed-by: Alan Maguire Link: https://lore.kernel.org/bpf/20240624090908.171231-1-atenart@kernel.org --- src/btf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/btf.c b/src/btf.c index 0c0f60c..cd5dd66 100644 --- a/src/btf.c +++ b/src/btf.c @@ -601,7 +601,7 @@ static int btf_sanity_check(const struct btf *btf) __u32 i, n = btf__type_cnt(btf); int err; - for (i = 1; i < n; i++) { + for (i = btf->start_id; i < n; i++) { t = btf_type_by_id(btf, i); err = btf_validate_type(btf, t, i); if (err) From e4982342e7850366ebd8d7bf1a4911bac42865b5 Mon Sep 17 00:00:00 2001 From: Alan Maguire Date: Mon, 24 Jun 2024 20:29:03 +0100 Subject: [PATCH 17/26] libbpf: Fix clang compilation error in btf_relocate.c When building with clang for ARCH=i386, the following errors are observed: CC kernel/bpf/btf_relocate.o ./tools/lib/bpf/btf_relocate.c:206:23: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion] 206 | info[id].needs_size = true; | ^ ~ ./tools/lib/bpf/btf_relocate.c:256:25: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion] 256 | base_info.needs_size = true; | ^ ~ 2 errors generated. The problem is we use 1-bit, 31-bit bitfields in a signed int. Changing to bool needs_size: 1; unsigned int size:31; ...resolves the error and pahole reports that 4 bytes are used for the underlying representation: $ pahole btf_name_info tools/lib/bpf/btf_relocate.o struct btf_name_info { const char * name; /* 0 8 */ unsigned int needs_size:1; /* 8: 0 4 */ unsigned int size:31; /* 8: 1 4 */ __u32 id; /* 12 4 */ /* size: 16, cachelines: 1, members: 4 */ /* last cacheline: 16 bytes */ }; Signed-off-by: Alan Maguire Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20240624192903.854261-1-alan.maguire@oracle.com --- src/btf_relocate.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/btf_relocate.c b/src/btf_relocate.c index 2281dbb..17f8b32 100644 --- a/src/btf_relocate.c +++ b/src/btf_relocate.c @@ -58,8 +58,8 @@ struct btf_relocate { struct btf_name_info { const char *name; /* set when search requires a size match */ - int needs_size:1, - size:31; + bool needs_size: 1; + unsigned int size: 31; __u32 id; }; From dcd076347c70c4738556ad565665c1d0776a4b37 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 26 Jun 2024 17:20:32 -0700 Subject: [PATCH 18/26] sync: update .mailmap Update .mailmap based on libbpf's list of contributors and on the latest .mailmap version in the upstream repository. Signed-off-by: Andrii Nakryiko --- .mailmap | 2 ++ 1 file changed, 2 insertions(+) diff --git a/.mailmap b/.mailmap index 2829ce6..1b013b1 100644 --- a/.mailmap +++ b/.mailmap @@ -8,6 +8,7 @@ Dan Carpenter Geliang Tang Herbert Xu Jakub Kicinski +Kees Cook Leo Yan Mark Starovoytov Maxim Mikityanskiy @@ -15,4 +16,5 @@ Maxim Mikityanskiy Puranjay Mohan Quentin Monnet Quentin Monnet +Vadim Fedorenko Vadim Fedorenko From 223cd2273e2e2cdab2687954a53c49948f333529 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 26 Jun 2024 17:20:32 -0700 Subject: [PATCH 19/26] sync: latest libbpf changes from kernel Syncing latest libbpf commits from kernel repository. Baseline bpf-next commit: 531876c80004ecff7bfdbd8ba6c6b48835ef5e22 Checkpoint bpf-next commit: a12978712d9001b060bcc10eaae42ad5102abe2b Baseline bpf commit: 62da3acd28955e7299babebdfcb14243b789e773 Checkpoint bpf commit: b1c4b4d45263241ec6c2405a8df8265d4b58e707 Alan Maguire (6): libbpf: Add btf__distill_base() creating split BTF with distilled base BTF libbpf: Split BTF relocation libbpf: BTF relocation followup fixing naming, loop logic libbpf: Split field iter code into its own file kernel libbpf,bpf: Share BTF relocate-related code with kernel libbpf: Fix clang compilation error in btf_relocate.c Andrii Nakryiko (4): libbpf: Add BTF field iterator libbpf: Make use of BTF field iterator in BPF linker code libbpf: Make use of BTF field iterator in BTF handling code libbpf: Remove callback-based type/string BTF field visitor helpers Antoine Tenart (1): libbpf: Skip base btf sanity checks Donglin Peng (1): libbpf: Checking the btf_type kind when fixing variable offsets Eduard Zingerman (1): libbpf: Make btf_parse_elf process .BTF.base transparently Mykyta Yatsenko (1): libbpf: Auto-attach struct_ops BPF maps in BPF skeleton Vadim Fedorenko (1): bpf: Add CHECKSUM_COMPLETE to bpf test progs include/uapi/linux/bpf.h | 2 + src/btf.c | 696 +++++++++++++++++++++++++++------------ src/btf.h | 36 ++ src/btf_iter.c | 177 ++++++++++ src/btf_relocate.c | 519 +++++++++++++++++++++++++++++ src/libbpf.c | 64 +++- src/libbpf.h | 18 + src/libbpf.map | 4 + src/libbpf_internal.h | 29 +- src/linker.c | 69 ++-- 10 files changed, 1378 insertions(+), 236 deletions(-) create mode 100644 src/btf_iter.c create mode 100644 src/btf_relocate.c Signed-off-by: Andrii Nakryiko --- BPF-CHECKPOINT-COMMIT | 2 +- CHECKPOINT-COMMIT | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/BPF-CHECKPOINT-COMMIT b/BPF-CHECKPOINT-COMMIT index c371997..b2b973f 100644 --- a/BPF-CHECKPOINT-COMMIT +++ b/BPF-CHECKPOINT-COMMIT @@ -1 +1 @@ -62da3acd28955e7299babebdfcb14243b789e773 +b1c4b4d45263241ec6c2405a8df8265d4b58e707 diff --git a/CHECKPOINT-COMMIT b/CHECKPOINT-COMMIT index d823cf4..df88dd3 100644 --- a/CHECKPOINT-COMMIT +++ b/CHECKPOINT-COMMIT @@ -1 +1 @@ -531876c80004ecff7bfdbd8ba6c6b48835ef5e22 +a12978712d9001b060bcc10eaae42ad5102abe2b From c1a6c770c46c6e78ad6755bf596c23a4e6f6b216 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 26 Jun 2024 20:16:40 -0700 Subject: [PATCH 20/26] libbpf: add btf_iter.o and btf_relocate.o to Makefile Upstream libbpf got two new .c files, make sure they are built with Github Makefile as well. Signed-off-by: Andrii Nakryiko --- src/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/Makefile b/src/Makefile index 53113da..547bafb 100644 --- a/src/Makefile +++ b/src/Makefile @@ -55,7 +55,7 @@ STATIC_OBJDIR := $(OBJDIR)/staticobjs OBJS := bpf.o btf.o libbpf.o libbpf_errno.o netlink.o \ nlattr.o str_error.o libbpf_probes.o bpf_prog_linfo.o \ btf_dump.o hashmap.o ringbuf.o strset.o linker.o gen_loader.o \ - relo_core.o usdt.o zip.o elf.o features.o + relo_core.o usdt.o zip.o elf.o features.o btf_iter.o btf_relocate.o SHARED_OBJS := $(addprefix $(SHARED_OBJDIR)/,$(OBJS)) STATIC_OBJS := $(addprefix $(STATIC_OBJDIR)/,$(OBJS)) From 24aca0740beafe8dd13464d6996cdf077dcd3b72 Mon Sep 17 00:00:00 2001 From: Alan Maguire Date: Sat, 29 Jun 2024 11:00:58 +0100 Subject: [PATCH 21/26] libbpf: Fix error handling in btf__distill_base() Coverity points out that after calling btf__new_empty_split() the wrong value is checked for error. Fixes: 58e185a0dc35 ("libbpf: Add btf__distill_base() creating split BTF with distilled base BTF") Reported-by: Andrii Nakryiko Signed-off-by: Alan Maguire Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20240629100058.2866763-1-alan.maguire@oracle.com --- src/btf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/btf.c b/src/btf.c index cd5dd66..32c00db 100644 --- a/src/btf.c +++ b/src/btf.c @@ -5431,7 +5431,7 @@ int btf__distill_base(const struct btf *src_btf, struct btf **new_base_btf, * BTF available. */ new_split = btf__new_empty_split(new_base); - if (!new_split_btf) { + if (!new_split) { err = -errno; goto done; } From 1867490d8fc635c552569d51c48debff588d2191 Mon Sep 17 00:00:00 2001 From: Andreas Ziegler Date: Wed, 3 Jul 2024 10:34:36 +0200 Subject: [PATCH 22/26] libbpf: Add NULL checks to bpf_object__{prev_map,next_map} In the current state, an erroneous call to bpf_object__find_map_by_name(NULL, ...) leads to a segmentation fault through the following call chain: bpf_object__find_map_by_name(obj = NULL, ...) -> bpf_object__for_each_map(pos, obj = NULL) -> bpf_object__next_map((obj = NULL), NULL) -> return (obj = NULL)->maps While calling bpf_object__find_map_by_name with obj = NULL is obviously incorrect, this should not lead to a segmentation fault but rather be handled gracefully. As __bpf_map__iter already handles this situation correctly, we can delegate the check for the regular case there and only add a check in case the prev or next parameter is NULL. Signed-off-by: Andreas Ziegler Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20240703083436.505124-1-ziegler.andreas@siemens.com --- src/libbpf.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/libbpf.c b/src/libbpf.c index 4a28fac..30f1217 100644 --- a/src/libbpf.c +++ b/src/libbpf.c @@ -10375,7 +10375,7 @@ __bpf_map__iter(const struct bpf_map *m, const struct bpf_object *obj, int i) struct bpf_map * bpf_object__next_map(const struct bpf_object *obj, const struct bpf_map *prev) { - if (prev == NULL) + if (prev == NULL && obj != NULL) return obj->maps; return __bpf_map__iter(prev, obj, 1); @@ -10384,7 +10384,7 @@ bpf_object__next_map(const struct bpf_object *obj, const struct bpf_map *prev) struct bpf_map * bpf_object__prev_map(const struct bpf_object *obj, const struct bpf_map *next) { - if (next == NULL) { + if (next == NULL && obj != NULL) { if (!obj->nr_maps) return NULL; return obj->maps + obj->nr_maps - 1; From bf7ddbef99d0c1e597c12b8b64ccd0c4d0c70282 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Mon, 8 Jul 2024 13:45:39 -0700 Subject: [PATCH 23/26] libbpf: fix BPF skeleton forward/backward compat handling BPF skeleton was designed from day one to be extensible. Generated BPF skeleton code specifies actual sizes of map/prog/variable skeletons for that reason and libbpf is supposed to work with newer/older versions correctly. Unfortunately, it was missed that we implicitly embed hard-coded most up-to-date (according to libbpf's version of libbpf.h header used to compile BPF skeleton header) sizes of those structs, which can differ from the actual sizes at runtime when libbpf is used as a shared library. We have a few places were we just index array of maps/progs/vars, which implicitly uses these potentially invalid sizes of structs. This patch aims to fix this problem going forward. Once this lands, we'll backport these changes in Github repo to create patched releases for older libbpfs. Acked-by: Eduard Zingerman Reviewed-by: Alan Maguire Fixes: d66562fba1ce ("libbpf: Add BPF object skeleton support") Fixes: 430025e5dca5 ("libbpf: Add subskeleton scaffolding") Fixes: 08ac454e258e ("libbpf: Auto-attach struct_ops BPF maps in BPF skeleton") Co-developed-by: Mykyta Yatsenko Signed-off-by: Mykyta Yatsenko Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20240708204540.4188946-3-andrii@kernel.org Signed-off-by: Alexei Starovoitov --- src/libbpf.c | 47 +++++++++++++++++++++++++++-------------------- 1 file changed, 27 insertions(+), 20 deletions(-) diff --git a/src/libbpf.c b/src/libbpf.c index 30f1217..8625c94 100644 --- a/src/libbpf.c +++ b/src/libbpf.c @@ -13712,14 +13712,15 @@ int libbpf_num_possible_cpus(void) static int populate_skeleton_maps(const struct bpf_object *obj, struct bpf_map_skeleton *maps, - size_t map_cnt) + size_t map_cnt, size_t map_skel_sz) { int i; for (i = 0; i < map_cnt; i++) { - struct bpf_map **map = maps[i].map; - const char *name = maps[i].name; - void **mmaped = maps[i].mmaped; + struct bpf_map_skeleton *map_skel = (void *)maps + i * map_skel_sz; + struct bpf_map **map = map_skel->map; + const char *name = map_skel->name; + void **mmaped = map_skel->mmaped; *map = bpf_object__find_map_by_name(obj, name); if (!*map) { @@ -13736,13 +13737,14 @@ static int populate_skeleton_maps(const struct bpf_object *obj, static int populate_skeleton_progs(const struct bpf_object *obj, struct bpf_prog_skeleton *progs, - size_t prog_cnt) + size_t prog_cnt, size_t prog_skel_sz) { int i; for (i = 0; i < prog_cnt; i++) { - struct bpf_program **prog = progs[i].prog; - const char *name = progs[i].name; + struct bpf_prog_skeleton *prog_skel = (void *)progs + i * prog_skel_sz; + struct bpf_program **prog = prog_skel->prog; + const char *name = prog_skel->name; *prog = bpf_object__find_program_by_name(obj, name); if (!*prog) { @@ -13783,13 +13785,13 @@ int bpf_object__open_skeleton(struct bpf_object_skeleton *s, } *s->obj = obj; - err = populate_skeleton_maps(obj, s->maps, s->map_cnt); + err = populate_skeleton_maps(obj, s->maps, s->map_cnt, s->map_skel_sz); if (err) { pr_warn("failed to populate skeleton maps for '%s': %d\n", s->name, err); return libbpf_err(err); } - err = populate_skeleton_progs(obj, s->progs, s->prog_cnt); + err = populate_skeleton_progs(obj, s->progs, s->prog_cnt, s->prog_skel_sz); if (err) { pr_warn("failed to populate skeleton progs for '%s': %d\n", s->name, err); return libbpf_err(err); @@ -13819,20 +13821,20 @@ int bpf_object__open_subskeleton(struct bpf_object_subskeleton *s) return libbpf_err(-errno); } - err = populate_skeleton_maps(s->obj, s->maps, s->map_cnt); + err = populate_skeleton_maps(s->obj, s->maps, s->map_cnt, s->map_skel_sz); if (err) { pr_warn("failed to populate subskeleton maps: %d\n", err); return libbpf_err(err); } - err = populate_skeleton_progs(s->obj, s->progs, s->prog_cnt); + err = populate_skeleton_progs(s->obj, s->progs, s->prog_cnt, s->prog_skel_sz); if (err) { pr_warn("failed to populate subskeleton maps: %d\n", err); return libbpf_err(err); } for (var_idx = 0; var_idx < s->var_cnt; var_idx++) { - var_skel = &s->vars[var_idx]; + var_skel = (void *)s->vars + var_idx * s->var_skel_sz; map = *var_skel->map; map_type_id = bpf_map__btf_value_type_id(map); map_type = btf__type_by_id(btf, map_type_id); @@ -13879,10 +13881,11 @@ int bpf_object__load_skeleton(struct bpf_object_skeleton *s) } for (i = 0; i < s->map_cnt; i++) { - struct bpf_map *map = *s->maps[i].map; + struct bpf_map_skeleton *map_skel = (void *)s->maps + i * s->map_skel_sz; + struct bpf_map *map = *map_skel->map; size_t mmap_sz = bpf_map_mmap_sz(map); int prot, map_fd = map->fd; - void **mmaped = s->maps[i].mmaped; + void **mmaped = map_skel->mmaped; if (!mmaped) continue; @@ -13930,8 +13933,9 @@ int bpf_object__attach_skeleton(struct bpf_object_skeleton *s) int i, err; for (i = 0; i < s->prog_cnt; i++) { - struct bpf_program *prog = *s->progs[i].prog; - struct bpf_link **link = s->progs[i].link; + struct bpf_prog_skeleton *prog_skel = (void *)s->progs + i * s->prog_skel_sz; + struct bpf_program *prog = *prog_skel->prog; + struct bpf_link **link = prog_skel->link; if (!prog->autoload || !prog->autoattach) continue; @@ -13970,8 +13974,9 @@ int bpf_object__attach_skeleton(struct bpf_object_skeleton *s) return 0; for (i = 0; i < s->map_cnt; i++) { - struct bpf_map *map = *s->maps[i].map; - struct bpf_link **link = s->maps[i].link; + struct bpf_map_skeleton *map_skel = (void *)s->maps + i * s->map_skel_sz; + struct bpf_map *map = *map_skel->map; + struct bpf_link **link = map_skel->link; if (!map->autocreate || !map->autoattach) continue; @@ -14000,7 +14005,8 @@ void bpf_object__detach_skeleton(struct bpf_object_skeleton *s) int i; for (i = 0; i < s->prog_cnt; i++) { - struct bpf_link **link = s->progs[i].link; + struct bpf_prog_skeleton *prog_skel = (void *)s->progs + i * s->prog_skel_sz; + struct bpf_link **link = prog_skel->link; bpf_link__destroy(*link); *link = NULL; @@ -14010,7 +14016,8 @@ void bpf_object__detach_skeleton(struct bpf_object_skeleton *s) return; for (i = 0; i < s->map_cnt; i++) { - struct bpf_link **link = s->maps[i].link; + struct bpf_map_skeleton *map_skel = (void *)s->maps + i * s->map_skel_sz; + struct bpf_link **link = map_skel->link; if (link) { bpf_link__destroy(*link); From e6f1ae25570c95d259eeada63886ed6eada6f201 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Mon, 8 Jul 2024 13:45:40 -0700 Subject: [PATCH 24/26] libbpf: improve old BPF skeleton handling for map auto-attach Improve how we handle old BPF skeletons when it comes to BPF map auto-attachment. Emit one warn-level message per each struct_ops map that could have been auto-attached, if user provided recent enough BPF skeleton version. Don't spam log if there are no relevant struct_ops maps, though. This should help users realize that they probably need to regenerate BPF skeleton header with more recent bpftool/libbpf-cargo (or whatever other means of BPF skeleton generation). Signed-off-by: Andrii Nakryiko Acked-by: Eduard Zingerman Link: https://lore.kernel.org/r/20240708204540.4188946-4-andrii@kernel.org Signed-off-by: Alexei Starovoitov --- src/libbpf.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-) diff --git a/src/libbpf.c b/src/libbpf.c index 8625c94..a3be6f8 100644 --- a/src/libbpf.c +++ b/src/libbpf.c @@ -13967,32 +13967,34 @@ int bpf_object__attach_skeleton(struct bpf_object_skeleton *s) */ } - /* Skeleton is created with earlier version of bpftool - * which does not support auto-attachment - */ - if (s->map_skel_sz < sizeof(struct bpf_map_skeleton)) - return 0; for (i = 0; i < s->map_cnt; i++) { struct bpf_map_skeleton *map_skel = (void *)s->maps + i * s->map_skel_sz; struct bpf_map *map = *map_skel->map; - struct bpf_link **link = map_skel->link; + struct bpf_link **link; if (!map->autocreate || !map->autoattach) continue; - if (*link) - continue; - /* only struct_ops maps can be attached */ if (!bpf_map__is_struct_ops(map)) continue; - *link = bpf_map__attach_struct_ops(map); + /* skeleton is created with earlier version of bpftool, notify user */ + if (s->map_skel_sz < offsetofend(struct bpf_map_skeleton, link)) { + pr_warn("map '%s': BPF skeleton version is old, skipping map auto-attachment...\n", + bpf_map__name(map)); + continue; + } + + link = map_skel->link; + if (*link) + continue; + + *link = bpf_map__attach_struct_ops(map); if (!*link) { err = -errno; - pr_warn("map '%s': failed to auto-attach: %d\n", - bpf_map__name(map), err); + pr_warn("map '%s': failed to auto-attach: %d\n", bpf_map__name(map), err); return libbpf_err(err); } } From 726d7f372279451fcb464eee94dd6733a25954f3 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 10 Jul 2024 12:19:42 -0700 Subject: [PATCH 25/26] sync: update .mailmap Update .mailmap based on libbpf's list of contributors and on the latest .mailmap version in the upstream repository. Signed-off-by: Andrii Nakryiko --- .mailmap | 1 + 1 file changed, 1 insertion(+) diff --git a/.mailmap b/.mailmap index 1b013b1..8143d9d 100644 --- a/.mailmap +++ b/.mailmap @@ -16,5 +16,6 @@ Maxim Mikityanskiy Puranjay Mohan Quentin Monnet Quentin Monnet +Stanislav Fomichev Vadim Fedorenko Vadim Fedorenko From 686f600bca59e107af4040d0838ca2b02c14ff50 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 10 Jul 2024 12:19:42 -0700 Subject: [PATCH 26/26] sync: latest libbpf changes from kernel Syncing latest libbpf commits from kernel repository. Baseline bpf-next commit: a12978712d9001b060bcc10eaae42ad5102abe2b Checkpoint bpf-next commit: ec5b8c76ab1c6d163762d60cfbedcd27e7527144 Baseline bpf commit: b1c4b4d45263241ec6c2405a8df8265d4b58e707 Checkpoint bpf commit: e1533b6319ab9c3a97dad314dd88b3783bc41b69 Alan Maguire (1): libbpf: Fix error handling in btf__distill_base() Andreas Ziegler (1): libbpf: Add NULL checks to bpf_object__{prev_map,next_map} Andrii Nakryiko (2): libbpf: fix BPF skeleton forward/backward compat handling libbpf: improve old BPF skeleton handling for map auto-attach src/btf.c | 2 +- src/libbpf.c | 75 +++++++++++++++++++++++++++++----------------------- 2 files changed, 43 insertions(+), 34 deletions(-) Signed-off-by: Andrii Nakryiko --- BPF-CHECKPOINT-COMMIT | 2 +- CHECKPOINT-COMMIT | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/BPF-CHECKPOINT-COMMIT b/BPF-CHECKPOINT-COMMIT index b2b973f..a63dd87 100644 --- a/BPF-CHECKPOINT-COMMIT +++ b/BPF-CHECKPOINT-COMMIT @@ -1 +1 @@ -b1c4b4d45263241ec6c2405a8df8265d4b58e707 +e1533b6319ab9c3a97dad314dd88b3783bc41b69 diff --git a/CHECKPOINT-COMMIT b/CHECKPOINT-COMMIT index df88dd3..0205e2a 100644 --- a/CHECKPOINT-COMMIT +++ b/CHECKPOINT-COMMIT @@ -1 +1 @@ -a12978712d9001b060bcc10eaae42ad5102abe2b +ec5b8c76ab1c6d163762d60cfbedcd27e7527144