From: Alexei Starovoitov Date: Tue, 21 Mar 2023 20:38:53 +0000 (-0700) Subject: libbpf: Support kfunc detection in light skeleton. X-Git-Tag: v6.6.7~2736^2~129^2~68^2~1 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=708cdc5706a4701be9e5f81cb2e2b60b57f34c42;p=platform%2Fkernel%2Flinux-starfive.git libbpf: Support kfunc detection in light skeleton. Teach gen_loader to find {btf_id, btf_obj_fd} of kernel variables and kfuncs and populate corresponding ld_imm64 and bpf_call insns. Signed-off-by: Alexei Starovoitov Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20230321203854.3035-4-alexei.starovoitov@gmail.com --- diff --git a/tools/lib/bpf/bpf_gen_internal.h b/tools/lib/bpf/bpf_gen_internal.h index 2233089..fdf4440 100644 --- a/tools/lib/bpf/bpf_gen_internal.h +++ b/tools/lib/bpf/bpf_gen_internal.h @@ -11,6 +11,7 @@ struct ksym_relo_desc { int insn_idx; bool is_weak; bool is_typeless; + bool is_ld64; }; struct ksym_desc { @@ -24,6 +25,7 @@ struct ksym_desc { bool typeless; }; int insn; + bool is_ld64; }; struct bpf_gen { @@ -65,7 +67,7 @@ void bpf_gen__map_update_elem(struct bpf_gen *gen, int map_idx, void *value, __u void bpf_gen__map_freeze(struct bpf_gen *gen, int map_idx); void bpf_gen__record_attach_target(struct bpf_gen *gen, const char *name, enum bpf_attach_type type); void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak, - bool is_typeless, int kind, int insn_idx); + bool is_typeless, bool is_ld64, int kind, int insn_idx); void bpf_gen__record_relo_core(struct bpf_gen *gen, const struct bpf_core_relo *core_relo); void bpf_gen__populate_outer_map(struct bpf_gen *gen, int outer_map_idx, int key, int inner_map_idx); diff --git a/tools/lib/bpf/gen_loader.c b/tools/lib/bpf/gen_loader.c index b74c82b..83e8e3b 100644 --- a/tools/lib/bpf/gen_loader.c +++ b/tools/lib/bpf/gen_loader.c @@ -560,7 +560,7 @@ static void emit_find_attach_target(struct bpf_gen *gen) } void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak, - bool is_typeless, int kind, int insn_idx) + bool is_typeless, bool is_ld64, int kind, int insn_idx) { struct ksym_relo_desc *relo; @@ -574,6 +574,7 @@ void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak, relo->name = name; relo->is_weak = is_weak; relo->is_typeless = is_typeless; + relo->is_ld64 = is_ld64; relo->kind = kind; relo->insn_idx = insn_idx; gen->relo_cnt++; @@ -586,9 +587,11 @@ static struct ksym_desc *get_ksym_desc(struct bpf_gen *gen, struct ksym_relo_des int i; for (i = 0; i < gen->nr_ksyms; i++) { - if (!strcmp(gen->ksyms[i].name, relo->name)) { - gen->ksyms[i].ref++; - return &gen->ksyms[i]; + kdesc = &gen->ksyms[i]; + if (kdesc->kind == relo->kind && kdesc->is_ld64 == relo->is_ld64 && + !strcmp(kdesc->name, relo->name)) { + kdesc->ref++; + return kdesc; } } kdesc = libbpf_reallocarray(gen->ksyms, gen->nr_ksyms + 1, sizeof(*kdesc)); @@ -603,6 +606,7 @@ static struct ksym_desc *get_ksym_desc(struct bpf_gen *gen, struct ksym_relo_des kdesc->ref = 1; kdesc->off = 0; kdesc->insn = 0; + kdesc->is_ld64 = relo->is_ld64; return kdesc; } @@ -864,23 +868,17 @@ static void emit_relo(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insn { int insn; - pr_debug("gen: emit_relo (%d): %s at %d\n", relo->kind, relo->name, relo->insn_idx); + pr_debug("gen: emit_relo (%d): %s at %d %s\n", + relo->kind, relo->name, relo->insn_idx, relo->is_ld64 ? "ld64" : "call"); insn = insns + sizeof(struct bpf_insn) * relo->insn_idx; emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_8, BPF_PSEUDO_MAP_IDX_VALUE, 0, 0, 0, insn)); - switch (relo->kind) { - case BTF_KIND_VAR: + if (relo->is_ld64) { if (relo->is_typeless) emit_relo_ksym_typeless(gen, relo, insn); else emit_relo_ksym_btf(gen, relo, insn); - break; - case BTF_KIND_FUNC: + } else { emit_relo_kfunc_btf(gen, relo, insn); - break; - default: - pr_warn("Unknown relocation kind '%d'\n", relo->kind); - gen->error = -EDOM; - return; } } @@ -903,18 +901,20 @@ static void cleanup_core_relo(struct bpf_gen *gen) static void cleanup_relos(struct bpf_gen *gen, int insns) { + struct ksym_desc *kdesc; int i, insn; for (i = 0; i < gen->nr_ksyms; i++) { + kdesc = &gen->ksyms[i]; /* only close fds for typed ksyms and kfuncs */ - if (gen->ksyms[i].kind == BTF_KIND_VAR && !gen->ksyms[i].typeless) { + if (kdesc->is_ld64 && !kdesc->typeless) { /* close fd recorded in insn[insn_idx + 1].imm */ - insn = gen->ksyms[i].insn; + insn = kdesc->insn; insn += sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm); emit_sys_close_blob(gen, insn); - } else if (gen->ksyms[i].kind == BTF_KIND_FUNC) { - emit_sys_close_blob(gen, blob_fd_array_off(gen, gen->ksyms[i].off)); - if (gen->ksyms[i].off < MAX_FD_ARRAY_SZ) + } else if (!kdesc->is_ld64) { + emit_sys_close_blob(gen, blob_fd_array_off(gen, kdesc->off)); + if (kdesc->off < MAX_FD_ARRAY_SZ) gen->nr_fd_array--; } } diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index f8131f9..5d32aa8 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -7070,18 +7070,21 @@ static int bpf_program_record_relos(struct bpf_program *prog) for (i = 0; i < prog->nr_reloc; i++) { struct reloc_desc *relo = &prog->reloc_desc[i]; struct extern_desc *ext = &obj->externs[relo->sym_off]; + int kind; switch (relo->type) { case RELO_EXTERN_LD64: if (ext->type != EXT_KSYM) continue; + kind = btf_is_var(btf__type_by_id(obj->btf, ext->btf_id)) ? + BTF_KIND_VAR : BTF_KIND_FUNC; bpf_gen__record_extern(obj->gen_loader, ext->name, ext->is_weak, !ext->ksym.type_id, - BTF_KIND_VAR, relo->insn_idx); + true, kind, relo->insn_idx); break; case RELO_EXTERN_CALL: bpf_gen__record_extern(obj->gen_loader, ext->name, - ext->is_weak, false, BTF_KIND_FUNC, + ext->is_weak, false, false, BTF_KIND_FUNC, relo->insn_idx); break; case RELO_CORE: {