From b8f871fa32ad392759bc70090fa8c60d9f10625c Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Fri, 26 Feb 2021 12:49:29 -0800 Subject: libbpf: Move function is_ldimm64() earlier in libbpf.c Move function is_ldimm64() close to the beginning of libbpf.c, so it can be reused by later code and the next patch as well. There is no functionality change. Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210226204929.3885295-1-yhs@fb.com --- tools/lib/bpf/libbpf.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index d43cc3f29dae..21a3eedf070d 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -574,6 +574,11 @@ static bool insn_is_subprog_call(const struct bpf_insn *insn) insn->off == 0; } +static bool is_ldimm64(struct bpf_insn *insn) +{ + return insn->code == (BPF_LD | BPF_IMM | BPF_DW); +} + static int bpf_object__init_prog(struct bpf_object *obj, struct bpf_program *prog, const char *name, size_t sec_idx, const char *sec_name, @@ -3395,7 +3400,7 @@ static int bpf_program__record_reloc(struct bpf_program *prog, return 0; } - if (insn->code != (BPF_LD | BPF_IMM | BPF_DW)) { + if (!is_ldimm64(insn)) { pr_warn("prog '%s': invalid relo against '%s' for insns[%d].code 0x%x\n", prog->name, sym_name, insn_idx, insn->code); return -LIBBPF_ERRNO__RELOC; @@ -5566,11 +5571,6 @@ static void bpf_core_poison_insn(struct bpf_program *prog, int relo_idx, insn->imm = 195896080; /* => 0xbad2310 => "bad relo" */ } -static bool is_ldimm64(struct bpf_insn *insn) -{ - return insn->code == (BPF_LD | BPF_IMM | BPF_DW); -} - static int insn_bpf_size_to_bytes(struct bpf_insn *insn) { switch (BPF_SIZE(insn->code)) { -- cgit v1.2.3 From 53eddb5e04ac5c53a4ccef9f1f900562a5a75246 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Fri, 26 Feb 2021 12:49:30 -0800 Subject: libbpf: Support subprog address relocation A new relocation RELO_SUBPROG_ADDR is added to capture subprog addresses loaded with ld_imm64 insns. Such ld_imm64 insns are marked with BPF_PSEUDO_FUNC and will be passed to kernel. For bpf_for_each_map_elem() case, kernel will check that the to-be-used subprog address must be a static function and replace it with proper actual jited func address. Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210226204930.3885367-1-yhs@fb.com --- tools/lib/bpf/libbpf.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 61 insertions(+), 3 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 21a3eedf070d..62d9ed56b081 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -188,6 +188,7 @@ enum reloc_type { RELO_CALL, RELO_DATA, RELO_EXTERN, + RELO_SUBPROG_ADDR, }; struct reloc_desc { @@ -579,6 +580,11 @@ static bool is_ldimm64(struct bpf_insn *insn) return insn->code == (BPF_LD | BPF_IMM | BPF_DW); } +static bool insn_is_pseudo_func(struct bpf_insn *insn) +{ + return is_ldimm64(insn) && insn->src_reg == BPF_PSEUDO_FUNC; +} + static int bpf_object__init_prog(struct bpf_object *obj, struct bpf_program *prog, const char *name, size_t sec_idx, const char *sec_name, @@ -2979,6 +2985,23 @@ static bool sym_is_extern(const GElf_Sym *sym) GELF_ST_TYPE(sym->st_info) == STT_NOTYPE; } +static bool sym_is_subprog(const GElf_Sym *sym, int text_shndx) +{ + int bind = GELF_ST_BIND(sym->st_info); + int type = GELF_ST_TYPE(sym->st_info); + + /* in .text section */ + if (sym->st_shndx != text_shndx) + return false; + + /* local function */ + if (bind == STB_LOCAL && type == STT_SECTION) + return true; + + /* global function */ + return bind == STB_GLOBAL && type == STT_FUNC; +} + static int find_extern_btf_id(const struct btf *btf, const char *ext_name) { const struct btf_type *t; @@ -3435,6 +3458,23 @@ static int bpf_program__record_reloc(struct bpf_program *prog, return -LIBBPF_ERRNO__RELOC; } + /* loading subprog addresses */ + if (sym_is_subprog(sym, obj->efile.text_shndx)) { + /* global_func: sym->st_value = offset in the section, insn->imm = 0. + * local_func: sym->st_value = 0, insn->imm = offset in the section. + */ + if ((sym->st_value % BPF_INSN_SZ) || (insn->imm % BPF_INSN_SZ)) { + pr_warn("prog '%s': bad subprog addr relo against '%s' at offset %zu+%d\n", + prog->name, sym_name, (size_t)sym->st_value, insn->imm); + return -LIBBPF_ERRNO__RELOC; + } + + reloc_desc->type = RELO_SUBPROG_ADDR; + reloc_desc->insn_idx = insn_idx; + reloc_desc->sym_off = sym->st_value; + return 0; + } + type = bpf_object__section_to_libbpf_map_type(obj, shdr_idx); sym_sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, shdr_idx)); @@ -6172,6 +6212,10 @@ bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog) } relo->processed = true; break; + case RELO_SUBPROG_ADDR: + insn[0].src_reg = BPF_PSEUDO_FUNC; + /* will be handled as a follow up pass */ + break; case RELO_CALL: /* will be handled as a follow up pass */ break; @@ -6358,11 +6402,11 @@ bpf_object__reloc_code(struct bpf_object *obj, struct bpf_program *main_prog, for (insn_idx = 0; insn_idx < prog->sec_insn_cnt; insn_idx++) { insn = &main_prog->insns[prog->sub_insn_off + insn_idx]; - if (!insn_is_subprog_call(insn)) + if (!insn_is_subprog_call(insn) && !insn_is_pseudo_func(insn)) continue; relo = find_prog_insn_relo(prog, insn_idx); - if (relo && relo->type != RELO_CALL) { + if (relo && relo->type != RELO_CALL && relo->type != RELO_SUBPROG_ADDR) { pr_warn("prog '%s': unexpected relo for insn #%zu, type %d\n", prog->name, insn_idx, relo->type); return -LIBBPF_ERRNO__RELOC; @@ -6374,8 +6418,22 @@ bpf_object__reloc_code(struct bpf_object *obj, struct bpf_program *main_prog, * call always has imm = -1, but for static functions * relocation is against STT_SECTION and insn->imm * points to a start of a static function + * + * for subprog addr relocation, the relo->sym_off + insn->imm is + * the byte offset in the corresponding section. */ - sub_insn_idx = relo->sym_off / BPF_INSN_SZ + insn->imm + 1; + if (relo->type == RELO_CALL) + sub_insn_idx = relo->sym_off / BPF_INSN_SZ + insn->imm + 1; + else + sub_insn_idx = (relo->sym_off + insn->imm) / BPF_INSN_SZ; + } else if (insn_is_pseudo_func(insn)) { + /* + * RELO_SUBPROG_ADDR relo is always emitted even if both + * functions are in the same section, so it shouldn't reach here. + */ + pr_warn("prog '%s': missing subprog addr relo for insn #%zu\n", + prog->name, insn_idx); + return -LIBBPF_ERRNO__RELOC; } else { /* if subprogram call is to a static function within * the same ELF section, there won't be any relocation -- cgit v1.2.3 From 1b1ce92b24331b569a444858fc487a1ca19dc778 Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Fri, 26 Feb 2021 21:22:48 +0100 Subject: libbpf: Fix whitespace in btf_add_composite() comment Remove trailing space. Signed-off-by: Ilya Leoshkevich Signed-off-by: Alexei Starovoitov Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20210226202256.116518-3-iii@linux.ibm.com --- tools/lib/bpf/btf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index d9c10830d749..0797ab714830 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -1883,7 +1883,7 @@ static int btf_add_composite(struct btf *btf, int kind, const char *name, __u32 * - *byte_sz* - size of the struct, in bytes; * * Struct initially has no fields in it. Fields can be added by - * btf__add_field() right after btf__add_struct() succeeds. + * btf__add_field() right after btf__add_struct() succeeds. * * Returns: * - >0, type ID of newly added BTF type; -- cgit v1.2.3 From 22541a9eeb0d968c133aaebd95fa59da3208e705 Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Fri, 26 Feb 2021 21:22:49 +0100 Subject: libbpf: Add BTF_KIND_FLOAT support The logic follows that of BTF_KIND_INT most of the time. Sanitization replaces BTF_KIND_FLOATs with equally-sized empty BTF_KIND_STRUCTs on older kernels, for example, the following: [4] FLOAT 'float' size=4 becomes the following: [4] STRUCT '(anon)' size=4 vlen=0 With dwarves patch [1] and this patch, the older kernels, which were failing with the floating-point-related errors, will now start working correctly. [1] https://github.com/iii-i/dwarves/commit/btf-kind-float-v2 Signed-off-by: Ilya Leoshkevich Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210226202256.116518-4-iii@linux.ibm.com --- tools/lib/bpf/btf.c | 49 +++++++++++++++++++++++++++++++++++++++++ tools/lib/bpf/btf.h | 6 +++++ tools/lib/bpf/btf_dump.c | 4 ++++ tools/lib/bpf/libbpf.c | 29 +++++++++++++++++++++++- tools/lib/bpf/libbpf.map | 5 +++++ tools/lib/bpf/libbpf_internal.h | 2 ++ 6 files changed, 94 insertions(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 0797ab714830..3aa58f2ac183 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -291,6 +291,7 @@ static int btf_type_size(const struct btf_type *t) case BTF_KIND_PTR: case BTF_KIND_TYPEDEF: case BTF_KIND_FUNC: + case BTF_KIND_FLOAT: return base_size; case BTF_KIND_INT: return base_size + sizeof(__u32); @@ -338,6 +339,7 @@ static int btf_bswap_type_rest(struct btf_type *t) case BTF_KIND_PTR: case BTF_KIND_TYPEDEF: case BTF_KIND_FUNC: + case BTF_KIND_FLOAT: return 0; case BTF_KIND_INT: *(__u32 *)(t + 1) = bswap_32(*(__u32 *)(t + 1)); @@ -578,6 +580,7 @@ __s64 btf__resolve_size(const struct btf *btf, __u32 type_id) case BTF_KIND_UNION: case BTF_KIND_ENUM: case BTF_KIND_DATASEC: + case BTF_KIND_FLOAT: size = t->size; goto done; case BTF_KIND_PTR: @@ -621,6 +624,7 @@ int btf__align_of(const struct btf *btf, __u32 id) switch (kind) { case BTF_KIND_INT: case BTF_KIND_ENUM: + case BTF_KIND_FLOAT: return min(btf_ptr_sz(btf), (size_t)t->size); case BTF_KIND_PTR: return btf_ptr_sz(btf); @@ -1756,6 +1760,47 @@ int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding return btf_commit_type(btf, sz); } +/* + * Append new BTF_KIND_FLOAT type with: + * - *name* - non-empty, non-NULL type name; + * - *sz* - size of the type, in bytes; + * Returns: + * - >0, type ID of newly added BTF type; + * - <0, on error. + */ +int btf__add_float(struct btf *btf, const char *name, size_t byte_sz) +{ + struct btf_type *t; + int sz, name_off; + + /* non-empty name */ + if (!name || !name[0]) + return -EINVAL; + + /* byte_sz must be one of the explicitly allowed values */ + if (byte_sz != 2 && byte_sz != 4 && byte_sz != 8 && byte_sz != 12 && + byte_sz != 16) + return -EINVAL; + + if (btf_ensure_modifiable(btf)) + return -ENOMEM; + + sz = sizeof(struct btf_type); + t = btf_add_type_mem(btf, sz); + if (!t) + return -ENOMEM; + + name_off = btf__add_str(btf, name); + if (name_off < 0) + return name_off; + + t->name_off = name_off; + t->info = btf_type_info(BTF_KIND_FLOAT, 0, 0); + t->size = byte_sz; + + return btf_commit_type(btf, sz); +} + /* it's completely legal to append BTF types with type IDs pointing forward to * types that haven't been appended yet, so we only make sure that id looks * sane, we can't guarantee that ID will always be valid @@ -3626,6 +3671,7 @@ static int btf_dedup_prep(struct btf_dedup *d) case BTF_KIND_FWD: case BTF_KIND_TYPEDEF: case BTF_KIND_FUNC: + case BTF_KIND_FLOAT: h = btf_hash_common(t); break; case BTF_KIND_INT: @@ -3722,6 +3768,7 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) break; case BTF_KIND_FWD: + case BTF_KIND_FLOAT: h = btf_hash_common(t); for_each_dedup_cand(d, hash_entry, h) { cand_id = (__u32)(long)hash_entry->value; @@ -3983,6 +4030,7 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id, return btf_compat_enum(cand_type, canon_type); case BTF_KIND_FWD: + case BTF_KIND_FLOAT: return btf_equal_common(cand_type, canon_type); case BTF_KIND_CONST: @@ -4479,6 +4527,7 @@ static int btf_dedup_remap_type(struct btf_dedup *d, __u32 type_id) switch (btf_kind(t)) { case BTF_KIND_INT: case BTF_KIND_ENUM: + case BTF_KIND_FLOAT: break; case BTF_KIND_FWD: diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index 1237bcd1dd17..029a9cfc8c2d 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -95,6 +95,7 @@ LIBBPF_API int btf__find_str(struct btf *btf, const char *s); LIBBPF_API int btf__add_str(struct btf *btf, const char *s); LIBBPF_API int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding); +LIBBPF_API int btf__add_float(struct btf *btf, const char *name, size_t byte_sz); LIBBPF_API int btf__add_ptr(struct btf *btf, int ref_type_id); LIBBPF_API int btf__add_array(struct btf *btf, int index_type_id, int elem_type_id, __u32 nr_elems); @@ -294,6 +295,11 @@ static inline bool btf_is_datasec(const struct btf_type *t) return btf_kind(t) == BTF_KIND_DATASEC; } +static inline bool btf_is_float(const struct btf_type *t) +{ + return btf_kind(t) == BTF_KIND_FLOAT; +} + static inline __u8 btf_int_encoding(const struct btf_type *t) { return BTF_INT_ENCODING(*(__u32 *)(t + 1)); diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index 2f9d685bd522..5e957fcceee6 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -279,6 +279,7 @@ static int btf_dump_mark_referenced(struct btf_dump *d) case BTF_KIND_INT: case BTF_KIND_ENUM: case BTF_KIND_FWD: + case BTF_KIND_FLOAT: break; case BTF_KIND_VOLATILE: @@ -453,6 +454,7 @@ static int btf_dump_order_type(struct btf_dump *d, __u32 id, bool through_ptr) switch (btf_kind(t)) { case BTF_KIND_INT: + case BTF_KIND_FLOAT: tstate->order_state = ORDERED; return 0; @@ -1133,6 +1135,7 @@ skip_mod: case BTF_KIND_STRUCT: case BTF_KIND_UNION: case BTF_KIND_TYPEDEF: + case BTF_KIND_FLOAT: goto done; default: pr_warn("unexpected type in decl chain, kind:%u, id:[%u]\n", @@ -1247,6 +1250,7 @@ static void btf_dump_emit_type_chain(struct btf_dump *d, switch (kind) { case BTF_KIND_INT: + case BTF_KIND_FLOAT: btf_dump_emit_mods(d, decls); name = btf_name_of(d, t->name_off); btf_dump_printf(d, "%s", name); diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 62d9ed56b081..2f351d3ad3e7 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -178,6 +178,8 @@ enum kern_feature_id { FEAT_PROG_BIND_MAP, /* Kernel support for module BTFs */ FEAT_MODULE_BTF, + /* BTF_KIND_FLOAT support */ + FEAT_BTF_FLOAT, __FEAT_CNT, }; @@ -1946,6 +1948,7 @@ static const char *btf_kind_str(const struct btf_type *t) case BTF_KIND_FUNC_PROTO: return "func_proto"; case BTF_KIND_VAR: return "var"; case BTF_KIND_DATASEC: return "datasec"; + case BTF_KIND_FLOAT: return "float"; default: return "unknown"; } } @@ -2395,15 +2398,17 @@ static bool btf_needs_sanitization(struct bpf_object *obj) { bool has_func_global = kernel_supports(FEAT_BTF_GLOBAL_FUNC); bool has_datasec = kernel_supports(FEAT_BTF_DATASEC); + bool has_float = kernel_supports(FEAT_BTF_FLOAT); bool has_func = kernel_supports(FEAT_BTF_FUNC); - return !has_func || !has_datasec || !has_func_global; + return !has_func || !has_datasec || !has_func_global || !has_float; } static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf) { bool has_func_global = kernel_supports(FEAT_BTF_GLOBAL_FUNC); bool has_datasec = kernel_supports(FEAT_BTF_DATASEC); + bool has_float = kernel_supports(FEAT_BTF_FLOAT); bool has_func = kernel_supports(FEAT_BTF_FUNC); struct btf_type *t; int i, j, vlen; @@ -2456,6 +2461,13 @@ static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf) } else if (!has_func_global && btf_is_func(t)) { /* replace BTF_FUNC_GLOBAL with BTF_FUNC_STATIC */ t->info = BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0); + } else if (!has_float && btf_is_float(t)) { + /* replace FLOAT with an equally-sized empty STRUCT; + * since C compilers do not accept e.g. "float" as a + * valid struct name, make it anonymous + */ + t->name_off = 0; + t->info = BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 0); } } } @@ -3927,6 +3939,18 @@ static int probe_kern_btf_datasec(void) strs, sizeof(strs))); } +static int probe_kern_btf_float(void) +{ + static const char strs[] = "\0float"; + __u32 types[] = { + /* float */ + BTF_TYPE_FLOAT_ENC(1, 4), + }; + + return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), + strs, sizeof(strs))); +} + static int probe_kern_array_mmap(void) { struct bpf_create_map_attr attr = { @@ -4106,6 +4130,9 @@ static struct kern_feature_desc { [FEAT_MODULE_BTF] = { "module BTF support", probe_module_btf, }, + [FEAT_BTF_FLOAT] = { + "BTF_KIND_FLOAT support", probe_kern_btf_float, + }, }; static bool kernel_supports(enum kern_feature_id feat_id) diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 1c0fd2dd233a..ec898f464ab9 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -350,3 +350,8 @@ LIBBPF_0.3.0 { xsk_setup_xdp_prog; xsk_socket__update_xskmap; } LIBBPF_0.2.0; + +LIBBPF_0.4.0 { + global: + btf__add_float; +} LIBBPF_0.3.0; diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 969d0ac592ba..343f6eb05637 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -31,6 +31,8 @@ #define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset) #define BTF_PARAM_ENC(name, type) (name), (type) #define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size) +#define BTF_TYPE_FLOAT_ENC(name, sz) \ + BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz) #ifndef likely #define likely(x) __builtin_expect(!!(x), 1) -- cgit v1.2.3 From 923a932c982fd71856f80dbeaaa3ca41a75e89e0 Mon Sep 17 00:00:00 2001 From: Joe Stringer Date: Tue, 2 Mar 2021 09:19:41 -0800 Subject: scripts/bpf: Abstract eBPF API target parameter MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Abstract out the target parameter so that upcoming commits, more than just the existing "helpers" target can be called to generate specific portions of docs from the eBPF UAPI headers. Signed-off-by: Joe Stringer Signed-off-by: Alexei Starovoitov Reviewed-by: Quentin Monnet Acked-by: Toke Høiland-Jørgensen Link: https://lore.kernel.org/bpf/20210302171947.2268128-10-joe@cilium.io --- MAINTAINERS | 1 + include/uapi/linux/bpf.h | 2 +- scripts/bpf_doc.py | 650 +++++++++++++++++++++++++++++++++++++++++ scripts/bpf_helpers_doc.py | 615 -------------------------------------- tools/bpf/Makefile.helpers | 2 +- tools/include/uapi/linux/bpf.h | 2 +- tools/lib/bpf/Makefile | 2 +- tools/perf/MANIFEST | 2 +- 8 files changed, 656 insertions(+), 620 deletions(-) create mode 100755 scripts/bpf_doc.py delete mode 100755 scripts/bpf_helpers_doc.py (limited to 'tools/lib') diff --git a/MAINTAINERS b/MAINTAINERS index a50a543e3c81..8d56c7044067 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -3223,6 +3223,7 @@ F: net/core/filter.c F: net/sched/act_bpf.c F: net/sched/cls_bpf.c F: samples/bpf/ +F: scripts/bpf_doc.py F: tools/bpf/ F: tools/lib/bpf/ F: tools/testing/selftests/bpf/ diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index c8b9d19fce22..63a56ed6a785 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1439,7 +1439,7 @@ union bpf_attr { * parsed and used to produce a manual page. The workflow is the following, * and requires the rst2man utility: * - * $ ./scripts/bpf_helpers_doc.py \ + * $ ./scripts/bpf_doc.py \ * --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst * $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7 * $ man /tmp/bpf-helpers.7 diff --git a/scripts/bpf_doc.py b/scripts/bpf_doc.py new file mode 100755 index 000000000000..5a4f68aab335 --- /dev/null +++ b/scripts/bpf_doc.py @@ -0,0 +1,650 @@ +#!/usr/bin/env python3 +# SPDX-License-Identifier: GPL-2.0-only +# +# Copyright (C) 2018-2019 Netronome Systems, Inc. +# Copyright (C) 2021 Isovalent, Inc. + +# In case user attempts to run with Python 2. +from __future__ import print_function + +import argparse +import re +import sys, os + +class NoHelperFound(BaseException): + pass + +class ParsingError(BaseException): + def __init__(self, line='', reader=None): + if reader: + BaseException.__init__(self, + 'Error at file offset %d, parsing line: %s' % + (reader.tell(), line)) + else: + BaseException.__init__(self, 'Error parsing line: %s' % line) + +class Helper(object): + """ + An object representing the description of an eBPF helper function. + @proto: function prototype of the helper function + @desc: textual description of the helper function + @ret: description of the return value of the helper function + """ + def __init__(self, proto='', desc='', ret=''): + self.proto = proto + self.desc = desc + self.ret = ret + + def proto_break_down(self): + """ + Break down helper function protocol into smaller chunks: return type, + name, distincts arguments. + """ + arg_re = re.compile('((\w+ )*?(\w+|...))( (\**)(\w+))?$') + res = {} + proto_re = re.compile('(.+) (\**)(\w+)\(((([^,]+)(, )?){1,5})\)$') + + capture = proto_re.match(self.proto) + res['ret_type'] = capture.group(1) + res['ret_star'] = capture.group(2) + res['name'] = capture.group(3) + res['args'] = [] + + args = capture.group(4).split(', ') + for a in args: + capture = arg_re.match(a) + res['args'].append({ + 'type' : capture.group(1), + 'star' : capture.group(5), + 'name' : capture.group(6) + }) + + return res + +class HeaderParser(object): + """ + An object used to parse a file in order to extract the documentation of a + list of eBPF helper functions. All the helpers that can be retrieved are + stored as Helper object, in the self.helpers() array. + @filename: name of file to parse, usually include/uapi/linux/bpf.h in the + kernel tree + """ + def __init__(self, filename): + self.reader = open(filename, 'r') + self.line = '' + self.helpers = [] + + def parse_helper(self): + proto = self.parse_proto() + desc = self.parse_desc() + ret = self.parse_ret() + return Helper(proto=proto, desc=desc, ret=ret) + + def parse_proto(self): + # Argument can be of shape: + # - "void" + # - "type name" + # - "type *name" + # - Same as above, with "const" and/or "struct" in front of type + # - "..." (undefined number of arguments, for bpf_trace_printk()) + # There is at least one term ("void"), and at most five arguments. + p = re.compile(' \* ?((.+) \**\w+\((((const )?(struct )?(\w+|\.\.\.)( \**\w+)?)(, )?){1,5}\))$') + capture = p.match(self.line) + if not capture: + raise NoHelperFound + self.line = self.reader.readline() + return capture.group(1) + + def parse_desc(self): + p = re.compile(' \* ?(?:\t| {5,8})Description$') + capture = p.match(self.line) + if not capture: + # Helper can have empty description and we might be parsing another + # attribute: return but do not consume. + return '' + # Description can be several lines, some of them possibly empty, and it + # stops when another subsection title is met. + desc = '' + while True: + self.line = self.reader.readline() + if self.line == ' *\n': + desc += '\n' + else: + p = re.compile(' \* ?(?:\t| {5,8})(?:\t| {8})(.*)') + capture = p.match(self.line) + if capture: + desc += capture.group(1) + '\n' + else: + break + return desc + + def parse_ret(self): + p = re.compile(' \* ?(?:\t| {5,8})Return$') + capture = p.match(self.line) + if not capture: + # Helper can have empty retval and we might be parsing another + # attribute: return but do not consume. + return '' + # Return value description can be several lines, some of them possibly + # empty, and it stops when another subsection title is met. + ret = '' + while True: + self.line = self.reader.readline() + if self.line == ' *\n': + ret += '\n' + else: + p = re.compile(' \* ?(?:\t| {5,8})(?:\t| {8})(.*)') + capture = p.match(self.line) + if capture: + ret += capture.group(1) + '\n' + else: + break + return ret + + def run(self): + # Advance to start of helper function descriptions. + offset = self.reader.read().find('* Start of BPF helper function descriptions:') + if offset == -1: + raise Exception('Could not find start of eBPF helper descriptions list') + self.reader.seek(offset) + self.reader.readline() + self.reader.readline() + self.line = self.reader.readline() + + while True: + try: + helper = self.parse_helper() + self.helpers.append(helper) + except NoHelperFound: + break + + self.reader.close() + +############################################################################### + +class Printer(object): + """ + A generic class for printers. Printers should be created with an array of + Helper objects, and implement a way to print them in the desired fashion. + @parser: A HeaderParser with objects to print to standard output + """ + def __init__(self, parser): + self.parser = parser + self.elements = [] + + def print_header(self): + pass + + def print_footer(self): + pass + + def print_one(self, helper): + pass + + def print_all(self): + self.print_header() + for elem in self.elements: + self.print_one(elem) + self.print_footer() + + +class PrinterRST(Printer): + """ + A generic class for printers that print ReStructured Text. Printers should + be created with a HeaderParser object, and implement a way to print API + elements in the desired fashion. + @parser: A HeaderParser with objects to print to standard output + """ + def __init__(self, parser): + self.parser = parser + + def print_license(self): + license = '''\ +.. Copyright (C) All BPF authors and contributors from 2014 to present. +.. See git log include/uapi/linux/bpf.h in kernel tree for details. +.. +.. %%%LICENSE_START(VERBATIM) +.. Permission is granted to make and distribute verbatim copies of this +.. manual provided the copyright notice and this permission notice are +.. preserved on all copies. +.. +.. Permission is granted to copy and distribute modified versions of this +.. manual under the conditions for verbatim copying, provided that the +.. entire resulting derived work is distributed under the terms of a +.. permission notice identical to this one. +.. +.. Since the Linux kernel and libraries are constantly changing, this +.. manual page may be incorrect or out-of-date. The author(s) assume no +.. responsibility for errors or omissions, or for damages resulting from +.. the use of the information contained herein. The author(s) may not +.. have taken the same level of care in the production of this manual, +.. which is licensed free of charge, as they might when working +.. professionally. +.. +.. Formatted or processed versions of this manual, if unaccompanied by +.. the source, must acknowledge the copyright and authors of this work. +.. %%%LICENSE_END +.. +.. Please do not edit this file. It was generated from the documentation +.. located in file include/uapi/linux/bpf.h of the Linux kernel sources +.. (helpers description), and from scripts/bpf_doc.py in the same +.. repository (header and footer). +''' + print(license) + + def print_elem(self, elem): + if (elem.desc): + print('\tDescription') + # Do not strip all newline characters: formatted code at the end of + # a section must be followed by a blank line. + for line in re.sub('\n$', '', elem.desc, count=1).split('\n'): + print('{}{}'.format('\t\t' if line else '', line)) + + if (elem.ret): + print('\tReturn') + for line in elem.ret.rstrip().split('\n'): + print('{}{}'.format('\t\t' if line else '', line)) + + print('') + + +class PrinterHelpersRST(PrinterRST): + """ + A printer for dumping collected information about helpers as a ReStructured + Text page compatible with the rst2man program, which can be used to + generate a manual page for the helpers. + @parser: A HeaderParser with Helper objects to print to standard output + """ + def __init__(self, parser): + self.elements = parser.helpers + + def print_header(self): + header = '''\ +=========== +BPF-HELPERS +=========== +------------------------------------------------------------------------------- +list of eBPF helper functions +------------------------------------------------------------------------------- + +:Manual section: 7 + +DESCRIPTION +=========== + +The extended Berkeley Packet Filter (eBPF) subsystem consists in programs +written in a pseudo-assembly language, then attached to one of the several +kernel hooks and run in reaction of specific events. This framework differs +from the older, "classic" BPF (or "cBPF") in several aspects, one of them being +the ability to call special functions (or "helpers") from within a program. +These functions are restricted to a white-list of helpers defined in the +kernel. + +These helpers are used by eBPF programs to interact with the system, or with +the context in which they work. For instance, they can be used to print +debugging messages, to get the time since the system was booted, to interact +with eBPF maps, or to manipulate network packets. Since there are several eBPF +program types, and that they do not run in the same context, each program type +can only call a subset of those helpers. + +Due to eBPF conventions, a helper can not have more than five arguments. + +Internally, eBPF programs call directly into the compiled helper functions +without requiring any foreign-function interface. As a result, calling helpers +introduces no overhead, thus offering excellent performance. + +This document is an attempt to list and document the helpers available to eBPF +developers. They are sorted by chronological order (the oldest helpers in the +kernel at the top). + +HELPERS +======= +''' + PrinterRST.print_license(self) + print(header) + + def print_footer(self): + footer = ''' +EXAMPLES +======== + +Example usage for most of the eBPF helpers listed in this manual page are +available within the Linux kernel sources, at the following locations: + +* *samples/bpf/* +* *tools/testing/selftests/bpf/* + +LICENSE +======= + +eBPF programs can have an associated license, passed along with the bytecode +instructions to the kernel when the programs are loaded. The format for that +string is identical to the one in use for kernel modules (Dual licenses, such +as "Dual BSD/GPL", may be used). Some helper functions are only accessible to +programs that are compatible with the GNU Privacy License (GPL). + +In order to use such helpers, the eBPF program must be loaded with the correct +license string passed (via **attr**) to the **bpf**\ () system call, and this +generally translates into the C source code of the program containing a line +similar to the following: + +:: + + char ____license[] __attribute__((section("license"), used)) = "GPL"; + +IMPLEMENTATION +============== + +This manual page is an effort to document the existing eBPF helper functions. +But as of this writing, the BPF sub-system is under heavy development. New eBPF +program or map types are added, along with new helper functions. Some helpers +are occasionally made available for additional program types. So in spite of +the efforts of the community, this page might not be up-to-date. If you want to +check by yourself what helper functions exist in your kernel, or what types of +programs they can support, here are some files among the kernel tree that you +may be interested in: + +* *include/uapi/linux/bpf.h* is the main BPF header. It contains the full list + of all helper functions, as well as many other BPF definitions including most + of the flags, structs or constants used by the helpers. +* *net/core/filter.c* contains the definition of most network-related helper + functions, and the list of program types from which they can be used. +* *kernel/trace/bpf_trace.c* is the equivalent for most tracing program-related + helpers. +* *kernel/bpf/verifier.c* contains the functions used to check that valid types + of eBPF maps are used with a given helper function. +* *kernel/bpf/* directory contains other files in which additional helpers are + defined (for cgroups, sockmaps, etc.). +* The bpftool utility can be used to probe the availability of helper functions + on the system (as well as supported program and map types, and a number of + other parameters). To do so, run **bpftool feature probe** (see + **bpftool-feature**\ (8) for details). Add the **unprivileged** keyword to + list features available to unprivileged users. + +Compatibility between helper functions and program types can generally be found +in the files where helper functions are defined. Look for the **struct +bpf_func_proto** objects and for functions returning them: these functions +contain a list of helpers that a given program type can call. Note that the +**default:** label of the **switch ... case** used to filter helpers can call +other functions, themselves allowing access to additional helpers. The +requirement for GPL license is also in those **struct bpf_func_proto**. + +Compatibility between helper functions and map types can be found in the +**check_map_func_compatibility**\ () function in file *kernel/bpf/verifier.c*. + +Helper functions that invalidate the checks on **data** and **data_end** +pointers for network processing are listed in function +**bpf_helper_changes_pkt_data**\ () in file *net/core/filter.c*. + +SEE ALSO +======== + +**bpf**\ (2), +**bpftool**\ (8), +**cgroups**\ (7), +**ip**\ (8), +**perf_event_open**\ (2), +**sendmsg**\ (2), +**socket**\ (7), +**tc-bpf**\ (8)''' + print(footer) + + def print_proto(self, helper): + """ + Format function protocol with bold and italics markers. This makes RST + file less readable, but gives nice results in the manual page. + """ + proto = helper.proto_break_down() + + print('**%s %s%s(' % (proto['ret_type'], + proto['ret_star'].replace('*', '\\*'), + proto['name']), + end='') + + comma = '' + for a in proto['args']: + one_arg = '{}{}'.format(comma, a['type']) + if a['name']: + if a['star']: + one_arg += ' {}**\ '.format(a['star'].replace('*', '\\*')) + else: + one_arg += '** ' + one_arg += '*{}*\\ **'.format(a['name']) + comma = ', ' + print(one_arg, end='') + + print(')**') + + def print_one(self, helper): + self.print_proto(helper) + self.print_elem(helper) + + + + +class PrinterHelpers(Printer): + """ + A printer for dumping collected information about helpers as C header to + be included from BPF program. + @parser: A HeaderParser with Helper objects to print to standard output + """ + def __init__(self, parser): + self.elements = parser.helpers + + type_fwds = [ + 'struct bpf_fib_lookup', + 'struct bpf_sk_lookup', + 'struct bpf_perf_event_data', + 'struct bpf_perf_event_value', + 'struct bpf_pidns_info', + 'struct bpf_redir_neigh', + 'struct bpf_sock', + 'struct bpf_sock_addr', + 'struct bpf_sock_ops', + 'struct bpf_sock_tuple', + 'struct bpf_spin_lock', + 'struct bpf_sysctl', + 'struct bpf_tcp_sock', + 'struct bpf_tunnel_key', + 'struct bpf_xfrm_state', + 'struct linux_binprm', + 'struct pt_regs', + 'struct sk_reuseport_md', + 'struct sockaddr', + 'struct tcphdr', + 'struct seq_file', + 'struct tcp6_sock', + 'struct tcp_sock', + 'struct tcp_timewait_sock', + 'struct tcp_request_sock', + 'struct udp6_sock', + 'struct task_struct', + + 'struct __sk_buff', + 'struct sk_msg_md', + 'struct xdp_md', + 'struct path', + 'struct btf_ptr', + 'struct inode', + 'struct socket', + 'struct file', + ] + known_types = { + '...', + 'void', + 'const void', + 'char', + 'const char', + 'int', + 'long', + 'unsigned long', + + '__be16', + '__be32', + '__wsum', + + 'struct bpf_fib_lookup', + 'struct bpf_perf_event_data', + 'struct bpf_perf_event_value', + 'struct bpf_pidns_info', + 'struct bpf_redir_neigh', + 'struct bpf_sk_lookup', + 'struct bpf_sock', + 'struct bpf_sock_addr', + 'struct bpf_sock_ops', + 'struct bpf_sock_tuple', + 'struct bpf_spin_lock', + 'struct bpf_sysctl', + 'struct bpf_tcp_sock', + 'struct bpf_tunnel_key', + 'struct bpf_xfrm_state', + 'struct linux_binprm', + 'struct pt_regs', + 'struct sk_reuseport_md', + 'struct sockaddr', + 'struct tcphdr', + 'struct seq_file', + 'struct tcp6_sock', + 'struct tcp_sock', + 'struct tcp_timewait_sock', + 'struct tcp_request_sock', + 'struct udp6_sock', + 'struct task_struct', + 'struct path', + 'struct btf_ptr', + 'struct inode', + 'struct socket', + 'struct file', + } + mapped_types = { + 'u8': '__u8', + 'u16': '__u16', + 'u32': '__u32', + 'u64': '__u64', + 's8': '__s8', + 's16': '__s16', + 's32': '__s32', + 's64': '__s64', + 'size_t': 'unsigned long', + 'struct bpf_map': 'void', + 'struct sk_buff': 'struct __sk_buff', + 'const struct sk_buff': 'const struct __sk_buff', + 'struct sk_msg_buff': 'struct sk_msg_md', + 'struct xdp_buff': 'struct xdp_md', + } + # Helpers overloaded for different context types. + overloaded_helpers = [ + 'bpf_get_socket_cookie', + 'bpf_sk_assign', + ] + + def print_header(self): + header = '''\ +/* This is auto-generated file. See bpf_doc.py for details. */ + +/* Forward declarations of BPF structs */''' + + print(header) + for fwd in self.type_fwds: + print('%s;' % fwd) + print('') + + def print_footer(self): + footer = '' + print(footer) + + def map_type(self, t): + if t in self.known_types: + return t + if t in self.mapped_types: + return self.mapped_types[t] + print("Unrecognized type '%s', please add it to known types!" % t, + file=sys.stderr) + sys.exit(1) + + seen_helpers = set() + + def print_one(self, helper): + proto = helper.proto_break_down() + + if proto['name'] in self.seen_helpers: + return + self.seen_helpers.add(proto['name']) + + print('/*') + print(" * %s" % proto['name']) + print(" *") + if (helper.desc): + # Do not strip all newline characters: formatted code at the end of + # a section must be followed by a blank line. + for line in re.sub('\n$', '', helper.desc, count=1).split('\n'): + print(' *{}{}'.format(' \t' if line else '', line)) + + if (helper.ret): + print(' *') + print(' * Returns') + for line in helper.ret.rstrip().split('\n'): + print(' *{}{}'.format(' \t' if line else '', line)) + + print(' */') + print('static %s %s(*%s)(' % (self.map_type(proto['ret_type']), + proto['ret_star'], proto['name']), end='') + comma = '' + for i, a in enumerate(proto['args']): + t = a['type'] + n = a['name'] + if proto['name'] in self.overloaded_helpers and i == 0: + t = 'void' + n = 'ctx' + one_arg = '{}{}'.format(comma, self.map_type(t)) + if n: + if a['star']: + one_arg += ' {}'.format(a['star']) + else: + one_arg += ' ' + one_arg += '{}'.format(n) + comma = ', ' + print(one_arg, end='') + + print(') = (void *) %d;' % len(self.seen_helpers)) + print('') + +############################################################################### + +# If script is launched from scripts/ from kernel tree and can access +# ../include/uapi/linux/bpf.h, use it as a default name for the file to parse, +# otherwise the --filename argument will be required from the command line. +script = os.path.abspath(sys.argv[0]) +linuxRoot = os.path.dirname(os.path.dirname(script)) +bpfh = os.path.join(linuxRoot, 'include/uapi/linux/bpf.h') + +printers = { + 'helpers': PrinterHelpersRST, +} + +argParser = argparse.ArgumentParser(description=""" +Parse eBPF header file and generate documentation for the eBPF API. +The RST-formatted output produced can be turned into a manual page with the +rst2man utility. +""") +argParser.add_argument('--header', action='store_true', + help='generate C header file') +if (os.path.isfile(bpfh)): + argParser.add_argument('--filename', help='path to include/uapi/linux/bpf.h', + default=bpfh) +else: + argParser.add_argument('--filename', help='path to include/uapi/linux/bpf.h') +argParser.add_argument('target', nargs='?', default='helpers', + choices=printers.keys(), help='eBPF API target') +args = argParser.parse_args() + +# Parse file. +headerParser = HeaderParser(args.filename) +headerParser.run() + +# Print formatted output to standard output. +if args.header: + printer = PrinterHelpers(headerParser) +else: + printer = printers[args.target](headerParser) +printer.print_all() diff --git a/scripts/bpf_helpers_doc.py b/scripts/bpf_helpers_doc.py deleted file mode 100755 index 867ada23281c..000000000000 --- a/scripts/bpf_helpers_doc.py +++ /dev/null @@ -1,615 +0,0 @@ -#!/usr/bin/env python3 -# SPDX-License-Identifier: GPL-2.0-only -# -# Copyright (C) 2018-2019 Netronome Systems, Inc. - -# In case user attempts to run with Python 2. -from __future__ import print_function - -import argparse -import re -import sys, os - -class NoHelperFound(BaseException): - pass - -class ParsingError(BaseException): - def __init__(self, line='', reader=None): - if reader: - BaseException.__init__(self, - 'Error at file offset %d, parsing line: %s' % - (reader.tell(), line)) - else: - BaseException.__init__(self, 'Error parsing line: %s' % line) - -class Helper(object): - """ - An object representing the description of an eBPF helper function. - @proto: function prototype of the helper function - @desc: textual description of the helper function - @ret: description of the return value of the helper function - """ - def __init__(self, proto='', desc='', ret=''): - self.proto = proto - self.desc = desc - self.ret = ret - - def proto_break_down(self): - """ - Break down helper function protocol into smaller chunks: return type, - name, distincts arguments. - """ - arg_re = re.compile('((\w+ )*?(\w+|...))( (\**)(\w+))?$') - res = {} - proto_re = re.compile('(.+) (\**)(\w+)\(((([^,]+)(, )?){1,5})\)$') - - capture = proto_re.match(self.proto) - res['ret_type'] = capture.group(1) - res['ret_star'] = capture.group(2) - res['name'] = capture.group(3) - res['args'] = [] - - args = capture.group(4).split(', ') - for a in args: - capture = arg_re.match(a) - res['args'].append({ - 'type' : capture.group(1), - 'star' : capture.group(5), - 'name' : capture.group(6) - }) - - return res - -class HeaderParser(object): - """ - An object used to parse a file in order to extract the documentation of a - list of eBPF helper functions. All the helpers that can be retrieved are - stored as Helper object, in the self.helpers() array. - @filename: name of file to parse, usually include/uapi/linux/bpf.h in the - kernel tree - """ - def __init__(self, filename): - self.reader = open(filename, 'r') - self.line = '' - self.helpers = [] - - def parse_helper(self): - proto = self.parse_proto() - desc = self.parse_desc() - ret = self.parse_ret() - return Helper(proto=proto, desc=desc, ret=ret) - - def parse_proto(self): - # Argument can be of shape: - # - "void" - # - "type name" - # - "type *name" - # - Same as above, with "const" and/or "struct" in front of type - # - "..." (undefined number of arguments, for bpf_trace_printk()) - # There is at least one term ("void"), and at most five arguments. - p = re.compile(' \* ?((.+) \**\w+\((((const )?(struct )?(\w+|\.\.\.)( \**\w+)?)(, )?){1,5}\))$') - capture = p.match(self.line) - if not capture: - raise NoHelperFound - self.line = self.reader.readline() - return capture.group(1) - - def parse_desc(self): - p = re.compile(' \* ?(?:\t| {5,8})Description$') - capture = p.match(self.line) - if not capture: - # Helper can have empty description and we might be parsing another - # attribute: return but do not consume. - return '' - # Description can be several lines, some of them possibly empty, and it - # stops when another subsection title is met. - desc = '' - while True: - self.line = self.reader.readline() - if self.line == ' *\n': - desc += '\n' - else: - p = re.compile(' \* ?(?:\t| {5,8})(?:\t| {8})(.*)') - capture = p.match(self.line) - if capture: - desc += capture.group(1) + '\n' - else: - break - return desc - - def parse_ret(self): - p = re.compile(' \* ?(?:\t| {5,8})Return$') - capture = p.match(self.line) - if not capture: - # Helper can have empty retval and we might be parsing another - # attribute: return but do not consume. - return '' - # Return value description can be several lines, some of them possibly - # empty, and it stops when another subsection title is met. - ret = '' - while True: - self.line = self.reader.readline() - if self.line == ' *\n': - ret += '\n' - else: - p = re.compile(' \* ?(?:\t| {5,8})(?:\t| {8})(.*)') - capture = p.match(self.line) - if capture: - ret += capture.group(1) + '\n' - else: - break - return ret - - def run(self): - # Advance to start of helper function descriptions. - offset = self.reader.read().find('* Start of BPF helper function descriptions:') - if offset == -1: - raise Exception('Could not find start of eBPF helper descriptions list') - self.reader.seek(offset) - self.reader.readline() - self.reader.readline() - self.line = self.reader.readline() - - while True: - try: - helper = self.parse_helper() - self.helpers.append(helper) - except NoHelperFound: - break - - self.reader.close() - -############################################################################### - -class Printer(object): - """ - A generic class for printers. Printers should be created with an array of - Helper objects, and implement a way to print them in the desired fashion. - @helpers: array of Helper objects to print to standard output - """ - def __init__(self, helpers): - self.helpers = helpers - - def print_header(self): - pass - - def print_footer(self): - pass - - def print_one(self, helper): - pass - - def print_all(self): - self.print_header() - for helper in self.helpers: - self.print_one(helper) - self.print_footer() - -class PrinterRST(Printer): - """ - A printer for dumping collected information about helpers as a ReStructured - Text page compatible with the rst2man program, which can be used to - generate a manual page for the helpers. - @helpers: array of Helper objects to print to standard output - """ - def print_header(self): - header = '''\ -.. Copyright (C) All BPF authors and contributors from 2014 to present. -.. See git log include/uapi/linux/bpf.h in kernel tree for details. -.. -.. %%%LICENSE_START(VERBATIM) -.. Permission is granted to make and distribute verbatim copies of this -.. manual provided the copyright notice and this permission notice are -.. preserved on all copies. -.. -.. Permission is granted to copy and distribute modified versions of this -.. manual under the conditions for verbatim copying, provided that the -.. entire resulting derived work is distributed under the terms of a -.. permission notice identical to this one. -.. -.. Since the Linux kernel and libraries are constantly changing, this -.. manual page may be incorrect or out-of-date. The author(s) assume no -.. responsibility for errors or omissions, or for damages resulting from -.. the use of the information contained herein. The author(s) may not -.. have taken the same level of care in the production of this manual, -.. which is licensed free of charge, as they might when working -.. professionally. -.. -.. Formatted or processed versions of this manual, if unaccompanied by -.. the source, must acknowledge the copyright and authors of this work. -.. %%%LICENSE_END -.. -.. Please do not edit this file. It was generated from the documentation -.. located in file include/uapi/linux/bpf.h of the Linux kernel sources -.. (helpers description), and from scripts/bpf_helpers_doc.py in the same -.. repository (header and footer). - -=========== -BPF-HELPERS -=========== -------------------------------------------------------------------------------- -list of eBPF helper functions -------------------------------------------------------------------------------- - -:Manual section: 7 - -DESCRIPTION -=========== - -The extended Berkeley Packet Filter (eBPF) subsystem consists in programs -written in a pseudo-assembly language, then attached to one of the several -kernel hooks and run in reaction of specific events. This framework differs -from the older, "classic" BPF (or "cBPF") in several aspects, one of them being -the ability to call special functions (or "helpers") from within a program. -These functions are restricted to a white-list of helpers defined in the -kernel. - -These helpers are used by eBPF programs to interact with the system, or with -the context in which they work. For instance, they can be used to print -debugging messages, to get the time since the system was booted, to interact -with eBPF maps, or to manipulate network packets. Since there are several eBPF -program types, and that they do not run in the same context, each program type -can only call a subset of those helpers. - -Due to eBPF conventions, a helper can not have more than five arguments. - -Internally, eBPF programs call directly into the compiled helper functions -without requiring any foreign-function interface. As a result, calling helpers -introduces no overhead, thus offering excellent performance. - -This document is an attempt to list and document the helpers available to eBPF -developers. They are sorted by chronological order (the oldest helpers in the -kernel at the top). - -HELPERS -======= -''' - print(header) - - def print_footer(self): - footer = ''' -EXAMPLES -======== - -Example usage for most of the eBPF helpers listed in this manual page are -available within the Linux kernel sources, at the following locations: - -* *samples/bpf/* -* *tools/testing/selftests/bpf/* - -LICENSE -======= - -eBPF programs can have an associated license, passed along with the bytecode -instructions to the kernel when the programs are loaded. The format for that -string is identical to the one in use for kernel modules (Dual licenses, such -as "Dual BSD/GPL", may be used). Some helper functions are only accessible to -programs that are compatible with the GNU Privacy License (GPL). - -In order to use such helpers, the eBPF program must be loaded with the correct -license string passed (via **attr**) to the **bpf**\ () system call, and this -generally translates into the C source code of the program containing a line -similar to the following: - -:: - - char ____license[] __attribute__((section("license"), used)) = "GPL"; - -IMPLEMENTATION -============== - -This manual page is an effort to document the existing eBPF helper functions. -But as of this writing, the BPF sub-system is under heavy development. New eBPF -program or map types are added, along with new helper functions. Some helpers -are occasionally made available for additional program types. So in spite of -the efforts of the community, this page might not be up-to-date. If you want to -check by yourself what helper functions exist in your kernel, or what types of -programs they can support, here are some files among the kernel tree that you -may be interested in: - -* *include/uapi/linux/bpf.h* is the main BPF header. It contains the full list - of all helper functions, as well as many other BPF definitions including most - of the flags, structs or constants used by the helpers. -* *net/core/filter.c* contains the definition of most network-related helper - functions, and the list of program types from which they can be used. -* *kernel/trace/bpf_trace.c* is the equivalent for most tracing program-related - helpers. -* *kernel/bpf/verifier.c* contains the functions used to check that valid types - of eBPF maps are used with a given helper function. -* *kernel/bpf/* directory contains other files in which additional helpers are - defined (for cgroups, sockmaps, etc.). -* The bpftool utility can be used to probe the availability of helper functions - on the system (as well as supported program and map types, and a number of - other parameters). To do so, run **bpftool feature probe** (see - **bpftool-feature**\ (8) for details). Add the **unprivileged** keyword to - list features available to unprivileged users. - -Compatibility between helper functions and program types can generally be found -in the files where helper functions are defined. Look for the **struct -bpf_func_proto** objects and for functions returning them: these functions -contain a list of helpers that a given program type can call. Note that the -**default:** label of the **switch ... case** used to filter helpers can call -other functions, themselves allowing access to additional helpers. The -requirement for GPL license is also in those **struct bpf_func_proto**. - -Compatibility between helper functions and map types can be found in the -**check_map_func_compatibility**\ () function in file *kernel/bpf/verifier.c*. - -Helper functions that invalidate the checks on **data** and **data_end** -pointers for network processing are listed in function -**bpf_helper_changes_pkt_data**\ () in file *net/core/filter.c*. - -SEE ALSO -======== - -**bpf**\ (2), -**bpftool**\ (8), -**cgroups**\ (7), -**ip**\ (8), -**perf_event_open**\ (2), -**sendmsg**\ (2), -**socket**\ (7), -**tc-bpf**\ (8)''' - print(footer) - - def print_proto(self, helper): - """ - Format function protocol with bold and italics markers. This makes RST - file less readable, but gives nice results in the manual page. - """ - proto = helper.proto_break_down() - - print('**%s %s%s(' % (proto['ret_type'], - proto['ret_star'].replace('*', '\\*'), - proto['name']), - end='') - - comma = '' - for a in proto['args']: - one_arg = '{}{}'.format(comma, a['type']) - if a['name']: - if a['star']: - one_arg += ' {}**\ '.format(a['star'].replace('*', '\\*')) - else: - one_arg += '** ' - one_arg += '*{}*\\ **'.format(a['name']) - comma = ', ' - print(one_arg, end='') - - print(')**') - - def print_one(self, helper): - self.print_proto(helper) - - if (helper.desc): - print('\tDescription') - # Do not strip all newline characters: formatted code at the end of - # a section must be followed by a blank line. - for line in re.sub('\n$', '', helper.desc, count=1).split('\n'): - print('{}{}'.format('\t\t' if line else '', line)) - - if (helper.ret): - print('\tReturn') - for line in helper.ret.rstrip().split('\n'): - print('{}{}'.format('\t\t' if line else '', line)) - - print('') - -class PrinterHelpers(Printer): - """ - A printer for dumping collected information about helpers as C header to - be included from BPF program. - @helpers: array of Helper objects to print to standard output - """ - - type_fwds = [ - 'struct bpf_fib_lookup', - 'struct bpf_sk_lookup', - 'struct bpf_perf_event_data', - 'struct bpf_perf_event_value', - 'struct bpf_pidns_info', - 'struct bpf_redir_neigh', - 'struct bpf_sock', - 'struct bpf_sock_addr', - 'struct bpf_sock_ops', - 'struct bpf_sock_tuple', - 'struct bpf_spin_lock', - 'struct bpf_sysctl', - 'struct bpf_tcp_sock', - 'struct bpf_tunnel_key', - 'struct bpf_xfrm_state', - 'struct linux_binprm', - 'struct pt_regs', - 'struct sk_reuseport_md', - 'struct sockaddr', - 'struct tcphdr', - 'struct seq_file', - 'struct tcp6_sock', - 'struct tcp_sock', - 'struct tcp_timewait_sock', - 'struct tcp_request_sock', - 'struct udp6_sock', - 'struct task_struct', - - 'struct __sk_buff', - 'struct sk_msg_md', - 'struct xdp_md', - 'struct path', - 'struct btf_ptr', - 'struct inode', - 'struct socket', - 'struct file', - ] - known_types = { - '...', - 'void', - 'const void', - 'char', - 'const char', - 'int', - 'long', - 'unsigned long', - - '__be16', - '__be32', - '__wsum', - - 'struct bpf_fib_lookup', - 'struct bpf_perf_event_data', - 'struct bpf_perf_event_value', - 'struct bpf_pidns_info', - 'struct bpf_redir_neigh', - 'struct bpf_sk_lookup', - 'struct bpf_sock', - 'struct bpf_sock_addr', - 'struct bpf_sock_ops', - 'struct bpf_sock_tuple', - 'struct bpf_spin_lock', - 'struct bpf_sysctl', - 'struct bpf_tcp_sock', - 'struct bpf_tunnel_key', - 'struct bpf_xfrm_state', - 'struct linux_binprm', - 'struct pt_regs', - 'struct sk_reuseport_md', - 'struct sockaddr', - 'struct tcphdr', - 'struct seq_file', - 'struct tcp6_sock', - 'struct tcp_sock', - 'struct tcp_timewait_sock', - 'struct tcp_request_sock', - 'struct udp6_sock', - 'struct task_struct', - 'struct path', - 'struct btf_ptr', - 'struct inode', - 'struct socket', - 'struct file', - } - mapped_types = { - 'u8': '__u8', - 'u16': '__u16', - 'u32': '__u32', - 'u64': '__u64', - 's8': '__s8', - 's16': '__s16', - 's32': '__s32', - 's64': '__s64', - 'size_t': 'unsigned long', - 'struct bpf_map': 'void', - 'struct sk_buff': 'struct __sk_buff', - 'const struct sk_buff': 'const struct __sk_buff', - 'struct sk_msg_buff': 'struct sk_msg_md', - 'struct xdp_buff': 'struct xdp_md', - } - # Helpers overloaded for different context types. - overloaded_helpers = [ - 'bpf_get_socket_cookie', - 'bpf_sk_assign', - ] - - def print_header(self): - header = '''\ -/* This is auto-generated file. See bpf_helpers_doc.py for details. */ - -/* Forward declarations of BPF structs */''' - - print(header) - for fwd in self.type_fwds: - print('%s;' % fwd) - print('') - - def print_footer(self): - footer = '' - print(footer) - - def map_type(self, t): - if t in self.known_types: - return t - if t in self.mapped_types: - return self.mapped_types[t] - print("Unrecognized type '%s', please add it to known types!" % t, - file=sys.stderr) - sys.exit(1) - - seen_helpers = set() - - def print_one(self, helper): - proto = helper.proto_break_down() - - if proto['name'] in self.seen_helpers: - return - self.seen_helpers.add(proto['name']) - - print('/*') - print(" * %s" % proto['name']) - print(" *") - if (helper.desc): - # Do not strip all newline characters: formatted code at the end of - # a section must be followed by a blank line. - for line in re.sub('\n$', '', helper.desc, count=1).split('\n'): - print(' *{}{}'.format(' \t' if line else '', line)) - - if (helper.ret): - print(' *') - print(' * Returns') - for line in helper.ret.rstrip().split('\n'): - print(' *{}{}'.format(' \t' if line else '', line)) - - print(' */') - print('static %s %s(*%s)(' % (self.map_type(proto['ret_type']), - proto['ret_star'], proto['name']), end='') - comma = '' - for i, a in enumerate(proto['args']): - t = a['type'] - n = a['name'] - if proto['name'] in self.overloaded_helpers and i == 0: - t = 'void' - n = 'ctx' - one_arg = '{}{}'.format(comma, self.map_type(t)) - if n: - if a['star']: - one_arg += ' {}'.format(a['star']) - else: - one_arg += ' ' - one_arg += '{}'.format(n) - comma = ', ' - print(one_arg, end='') - - print(') = (void *) %d;' % len(self.seen_helpers)) - print('') - -############################################################################### - -# If script is launched from scripts/ from kernel tree and can access -# ../include/uapi/linux/bpf.h, use it as a default name for the file to parse, -# otherwise the --filename argument will be required from the command line. -script = os.path.abspath(sys.argv[0]) -linuxRoot = os.path.dirname(os.path.dirname(script)) -bpfh = os.path.join(linuxRoot, 'include/uapi/linux/bpf.h') - -argParser = argparse.ArgumentParser(description=""" -Parse eBPF header file and generate documentation for eBPF helper functions. -The RST-formatted output produced can be turned into a manual page with the -rst2man utility. -""") -argParser.add_argument('--header', action='store_true', - help='generate C header file') -if (os.path.isfile(bpfh)): - argParser.add_argument('--filename', help='path to include/uapi/linux/bpf.h', - default=bpfh) -else: - argParser.add_argument('--filename', help='path to include/uapi/linux/bpf.h') -args = argParser.parse_args() - -# Parse file. -headerParser = HeaderParser(args.filename) -headerParser.run() - -# Print formatted output to standard output. -if args.header: - printer = PrinterHelpers(headerParser.helpers) -else: - printer = PrinterRST(headerParser.helpers) -printer.print_all() diff --git a/tools/bpf/Makefile.helpers b/tools/bpf/Makefile.helpers index 854d084026dd..a26599022fd6 100644 --- a/tools/bpf/Makefile.helpers +++ b/tools/bpf/Makefile.helpers @@ -35,7 +35,7 @@ man7: $(DOC_MAN7) RST2MAN_DEP := $(shell command -v rst2man 2>/dev/null) $(OUTPUT)$(HELPERS_RST): $(UP2DIR)../../include/uapi/linux/bpf.h - $(QUIET_GEN)$(UP2DIR)../../scripts/bpf_helpers_doc.py --filename $< > $@ + $(QUIET_GEN)$(UP2DIR)../../scripts/bpf_doc.py --filename $< > $@ $(OUTPUT)%.7: $(OUTPUT)%.rst ifndef RST2MAN_DEP diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index b89af20cfa19..b4c5c529ad17 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -729,7 +729,7 @@ union bpf_attr { * parsed and used to produce a manual page. The workflow is the following, * and requires the rst2man utility: * - * $ ./scripts/bpf_helpers_doc.py \ + * $ ./scripts/bpf_doc.py \ * --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst * $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7 * $ man /tmp/bpf-helpers.7 diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile index 887a494ad5fc..8170f88e8ea6 100644 --- a/tools/lib/bpf/Makefile +++ b/tools/lib/bpf/Makefile @@ -158,7 +158,7 @@ $(BPF_IN_STATIC): force $(BPF_HELPER_DEFS) $(Q)$(MAKE) $(build)=libbpf OUTPUT=$(STATIC_OBJDIR) $(BPF_HELPER_DEFS): $(srctree)/tools/include/uapi/linux/bpf.h - $(QUIET_GEN)$(srctree)/scripts/bpf_helpers_doc.py --header \ + $(QUIET_GEN)$(srctree)/scripts/bpf_doc.py --header \ --file $(srctree)/tools/include/uapi/linux/bpf.h > $(BPF_HELPER_DEFS) $(OUTPUT)libbpf.so: $(OUTPUT)libbpf.so.$(LIBBPF_VERSION) diff --git a/tools/perf/MANIFEST b/tools/perf/MANIFEST index 5d7b947320fb..f05c4d48fd7e 100644 --- a/tools/perf/MANIFEST +++ b/tools/perf/MANIFEST @@ -20,4 +20,4 @@ tools/lib/bitmap.c tools/lib/str_error_r.c tools/lib/vsprintf.c tools/lib/zalloc.c -scripts/bpf_helpers_doc.py +scripts/bpf_doc.py -- cgit v1.2.3 From 291471dd1559528a4c2ad5026eff94ed1030562b Mon Sep 17 00:00:00 2001 From: Björn Töpel Date: Fri, 5 Mar 2021 10:41:13 +0100 Subject: libbpf, xsk: Add libbpf_smp_store_release libbpf_smp_load_acquire MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Now that the AF_XDP rings have load-acquire/store-release semantics, move libbpf to that as well. The library-internal libbpf_smp_{load_acquire,store_release} are only valid for 32-bit words on ARM64. Also, remove the barriers that are no longer in use. Signed-off-by: Björn Töpel Signed-off-by: Andrii Nakryiko Acked-by: Toke Høiland-Jørgensen Link: https://lore.kernel.org/bpf/20210305094113.413544-3-bjorn.topel@gmail.com --- tools/lib/bpf/libbpf_util.h | 72 +++++++++++++++++++++++++++++++-------------- tools/lib/bpf/xsk.h | 17 ++++------- 2 files changed, 55 insertions(+), 34 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf_util.h b/tools/lib/bpf/libbpf_util.h index 59c779c5790c..94a0d7bb6f3c 100644 --- a/tools/lib/bpf/libbpf_util.h +++ b/tools/lib/bpf/libbpf_util.h @@ -5,6 +5,7 @@ #define __LIBBPF_LIBBPF_UTIL_H #include +#include #ifdef __cplusplus extern "C" { @@ -15,29 +16,56 @@ extern "C" { * application that uses libbpf. */ #if defined(__i386__) || defined(__x86_64__) -# define libbpf_smp_rmb() asm volatile("" : : : "memory") -# define libbpf_smp_wmb() asm volatile("" : : : "memory") -# define libbpf_smp_mb() \ - asm volatile("lock; addl $0,-4(%%rsp)" : : : "memory", "cc") -/* Hinders stores to be observed before older loads. */ -# define libbpf_smp_rwmb() asm volatile("" : : : "memory") +# define libbpf_smp_store_release(p, v) \ + do { \ + asm volatile("" : : : "memory"); \ + WRITE_ONCE(*p, v); \ + } while (0) +# define libbpf_smp_load_acquire(p) \ + ({ \ + typeof(*p) ___p1 = READ_ONCE(*p); \ + asm volatile("" : : : "memory"); \ + ___p1; \ + }) #elif defined(__aarch64__) -# define libbpf_smp_rmb() asm volatile("dmb ishld" : : : "memory") -# define libbpf_smp_wmb() asm volatile("dmb ishst" : : : "memory") -# define libbpf_smp_mb() asm volatile("dmb ish" : : : "memory") -# define libbpf_smp_rwmb() libbpf_smp_mb() -#elif defined(__arm__) -/* These are only valid for armv7 and above */ -# define libbpf_smp_rmb() asm volatile("dmb ish" : : : "memory") -# define libbpf_smp_wmb() asm volatile("dmb ishst" : : : "memory") -# define libbpf_smp_mb() asm volatile("dmb ish" : : : "memory") -# define libbpf_smp_rwmb() libbpf_smp_mb() -#else -/* Architecture missing native barrier functions. */ -# define libbpf_smp_rmb() __sync_synchronize() -# define libbpf_smp_wmb() __sync_synchronize() -# define libbpf_smp_mb() __sync_synchronize() -# define libbpf_smp_rwmb() __sync_synchronize() +# define libbpf_smp_store_release(p, v) \ + asm volatile ("stlr %w1, %0" : "=Q" (*p) : "r" (v) : "memory") +# define libbpf_smp_load_acquire(p) \ + ({ \ + typeof(*p) ___p1; \ + asm volatile ("ldar %w0, %1" \ + : "=r" (___p1) : "Q" (*p) : "memory"); \ + __p1; \ + }) +#elif defined(__riscv) +# define libbpf_smp_store_release(p, v) \ + do { \ + asm volatile ("fence rw,w" : : : "memory"); \ + WRITE_ONCE(*p, v); \ + } while (0) +# define libbpf_smp_load_acquire(p) \ + ({ \ + typeof(*p) ___p1 = READ_ONCE(*p); \ + asm volatile ("fence r,rw" : : : "memory"); \ + ___p1; \ + }) +#endif + +#ifndef libbpf_smp_store_release +#define libbpf_smp_store_release(p, v) \ + do { \ + __sync_synchronize(); \ + WRITE_ONCE(*p, v); \ + } while (0) +#endif + +#ifndef libbpf_smp_load_acquire +#define libbpf_smp_load_acquire(p) \ + ({ \ + typeof(*p) ___p1 = READ_ONCE(*p); \ + __sync_synchronize(); \ + ___p1; \ + }) #endif #ifdef __cplusplus diff --git a/tools/lib/bpf/xsk.h b/tools/lib/bpf/xsk.h index e9f121f5d129..a9fdea87b5cd 100644 --- a/tools/lib/bpf/xsk.h +++ b/tools/lib/bpf/xsk.h @@ -96,7 +96,8 @@ static inline __u32 xsk_prod_nb_free(struct xsk_ring_prod *r, __u32 nb) * this function. Without this optimization it whould have been * free_entries = r->cached_prod - r->cached_cons + r->size. */ - r->cached_cons = *r->consumer + r->size; + r->cached_cons = libbpf_smp_load_acquire(r->consumer); + r->cached_cons += r->size; return r->cached_cons - r->cached_prod; } @@ -106,7 +107,7 @@ static inline __u32 xsk_cons_nb_avail(struct xsk_ring_cons *r, __u32 nb) __u32 entries = r->cached_prod - r->cached_cons; if (entries == 0) { - r->cached_prod = *r->producer; + r->cached_prod = libbpf_smp_load_acquire(r->producer); entries = r->cached_prod - r->cached_cons; } @@ -129,9 +130,7 @@ static inline void xsk_ring_prod__submit(struct xsk_ring_prod *prod, __u32 nb) /* Make sure everything has been written to the ring before indicating * this to the kernel by writing the producer pointer. */ - libbpf_smp_wmb(); - - *prod->producer += nb; + libbpf_smp_store_release(prod->producer, *prod->producer + nb); } static inline __u32 xsk_ring_cons__peek(struct xsk_ring_cons *cons, __u32 nb, __u32 *idx) @@ -139,11 +138,6 @@ static inline __u32 xsk_ring_cons__peek(struct xsk_ring_cons *cons, __u32 nb, __ __u32 entries = xsk_cons_nb_avail(cons, nb); if (entries > 0) { - /* Make sure we do not speculatively read the data before - * we have received the packet buffers from the ring. - */ - libbpf_smp_rmb(); - *idx = cons->cached_cons; cons->cached_cons += entries; } @@ -161,9 +155,8 @@ static inline void xsk_ring_cons__release(struct xsk_ring_cons *cons, __u32 nb) /* Make sure data has been read before indicating we are done * with the entries by updating the consumer pointer. */ - libbpf_smp_rwmb(); + libbpf_smp_store_release(cons->consumer, *cons->consumer + nb); - *cons->consumer += nb; } static inline void *xsk_umem__get_data(void *umem_area, __u64 addr) -- cgit v1.2.3 From a6aac408c56112f73d28ea8567c29b2a7fe8fccc Mon Sep 17 00:00:00 2001 From: Jean-Philippe Brucker Date: Mon, 8 Mar 2021 19:25:22 +0100 Subject: libbpf: Fix arm64 build The macro for libbpf_smp_store_release() doesn't build on arm64, fix it. Fixes: 291471dd1559 ("libbpf, xsk: Add libbpf_smp_store_release libbpf_smp_load_acquire") Signed-off-by: Jean-Philippe Brucker Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210308182521.155536-1-jean-philippe@linaro.org --- tools/lib/bpf/libbpf_util.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf_util.h b/tools/lib/bpf/libbpf_util.h index 94a0d7bb6f3c..cfbcfc063c81 100644 --- a/tools/lib/bpf/libbpf_util.h +++ b/tools/lib/bpf/libbpf_util.h @@ -35,7 +35,7 @@ extern "C" { typeof(*p) ___p1; \ asm volatile ("ldar %w0, %1" \ : "=r" (___p1) : "Q" (*p) : "memory"); \ - __p1; \ + ___p1; \ }) #elif defined(__riscv) # define libbpf_smp_store_release(p, v) \ -- cgit v1.2.3