1 files changed, 143 insertions, 118 deletions

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index a7d183f7ac72..4c3592c4ec5d 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -276,8 +276,8 @@ struct bpf_object {
 		struct {
 			GElf_Shdr shdr;
 			Elf_Data *data;
-		} *reloc;
-		int nr_reloc;
+		} *reloc_sects;
+		int nr_reloc_sects;
 		int maps_shndx;
 		int btf_maps_shndx;
 		int text_shndx;
@@ -575,8 +575,8 @@ static void bpf_object__elf_finish(struct bpf_object *obj)
 	obj->efile.rodata = NULL;
 	obj->efile.bss = NULL;
 
-	zfree(&obj->efile.reloc);
-	obj->efile.nr_reloc = 0;
+	zfree(&obj->efile.reloc_sects);
+	obj->efile.nr_reloc_sects = 0;
 	zclose(obj->efile.fd);
 	obj->efile.obj_buf = NULL;
 	obj->efile.obj_buf_sz = 0;
@@ -1693,8 +1693,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj, bool relaxed_maps,
 				pr_debug("skip section(%d) %s\n", idx, name);
 			}
 		} else if (sh.sh_type == SHT_REL) {
-			int nr_reloc = obj->efile.nr_reloc;
-			void *reloc = obj->efile.reloc;
+			int nr_sects = obj->efile.nr_reloc_sects;
+			void *sects = obj->efile.reloc_sects;
 			int sec = sh.sh_info; /* points to other section */
 
 			/* Only do relo for section with exec instructions */
@@ -1704,18 +1704,18 @@ static int bpf_object__elf_collect(struct bpf_object *obj, bool relaxed_maps,
 				continue;
 			}
 
-			reloc = reallocarray(reloc, nr_reloc + 1,
-					     sizeof(*obj->efile.reloc));
-			if (!reloc) {
-				pr_warn("realloc failed\n");
+			sects = reallocarray(sects, nr_sects + 1,
+					     sizeof(*obj->efile.reloc_sects));
+			if (!sects) {
+				pr_warn("reloc_sects realloc failed\n");
 				return -ENOMEM;
 			}
 
-			obj->efile.reloc = reloc;
-			obj->efile.nr_reloc++;
+			obj->efile.reloc_sects = sects;
+			obj->efile.nr_reloc_sects++;
 
-			obj->efile.reloc[nr_reloc].shdr = sh;
-			obj->efile.reloc[nr_reloc].data = data;
+			obj->efile.reloc_sects[nr_sects].shdr = sh;
+			obj->efile.reloc_sects[nr_sects].data = data;
 		} else if (sh.sh_type == SHT_NOBITS && strcmp(name, ".bss") == 0) {
 			obj->efile.bss = data;
 			obj->efile.bss_shndx = idx;
@@ -1780,14 +1780,6 @@ static bool bpf_object__shndx_is_maps(const struct bpf_object *obj,
 	       shndx == obj->efile.btf_maps_shndx;
 }
 
-static bool bpf_object__relo_in_known_section(const struct bpf_object *obj,
-					      int shndx)
-{
-	return shndx == obj->efile.text_shndx ||
-	       bpf_object__shndx_is_maps(obj, shndx) ||
-	       bpf_object__shndx_is_data(obj, shndx);
-}
-
 static enum libbpf_map_type
 bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx)
 {
@@ -1801,14 +1793,124 @@ bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx)
 		return LIBBPF_MAP_UNSPEC;
 }
 
+static int bpf_program__record_reloc(struct bpf_program *prog,
+				     struct reloc_desc *reloc_desc,
+				     __u32 insn_idx, const char *name,
+				     const GElf_Sym *sym, const GElf_Rel *rel)
+{
+	struct bpf_insn *insn = &prog->insns[insn_idx];
+	size_t map_idx, nr_maps = prog->obj->nr_maps;
+	struct bpf_object *obj = prog->obj;
+	__u32 shdr_idx = sym->st_shndx;
+	enum libbpf_map_type type;
+	struct bpf_map *map;
+
+	/* sub-program call relocation */
+	if (insn->code == (BPF_JMP | BPF_CALL)) {
+		if (insn->src_reg != BPF_PSEUDO_CALL) {
+			pr_warn("incorrect bpf_call opcode\n");
+			return -LIBBPF_ERRNO__RELOC;
+		}
+		/* text_shndx can be 0, if no default "main" program exists */
+		if (!shdr_idx || shdr_idx != obj->efile.text_shndx) {
+			pr_warn("bad call relo against section %u\n", shdr_idx);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+		if (sym->st_value % 8) {
+			pr_warn("bad call relo offset: %lu\n", sym->st_value);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+		reloc_desc->type = RELO_CALL;
+		reloc_desc->insn_idx = insn_idx;
+		reloc_desc->text_off = sym->st_value / 8;
+		obj->has_pseudo_calls = true;
+		return 0;
+	}
+
+	if (insn->code != (BPF_LD | BPF_IMM | BPF_DW)) {
+		pr_warn("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
+			insn_idx, insn->code);
+		return -LIBBPF_ERRNO__RELOC;
+	}
+	if (!shdr_idx || shdr_idx >= SHN_LORESERVE) {
+		pr_warn("relocation: not yet supported relo for non-static global \'%s\' variable in special section (0x%x) found in insns[%d].code 0x%x\n",
+			name, shdr_idx, insn_idx, insn->code);
+		return -LIBBPF_ERRNO__RELOC;
+	}
+
+	type = bpf_object__section_to_libbpf_map_type(obj, shdr_idx);
+
+	/* generic map reference relocation */
+	if (type == LIBBPF_MAP_UNSPEC) {
+		if (!bpf_object__shndx_is_maps(obj, shdr_idx)) {
+			pr_warn("bad map relo against section %u\n",
+				shdr_idx);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+		for (map_idx = 0; map_idx < nr_maps; map_idx++) {
+			map = &obj->maps[map_idx];
+			if (map->libbpf_type != type ||
+			    map->sec_idx != sym->st_shndx ||
+			    map->sec_offset != sym->st_value)
+				continue;
+			pr_debug("found map %zd (%s, sec %d, off %zu) for insn %u\n",
+				 map_idx, map->name, map->sec_idx,
+				 map->sec_offset, insn_idx);
+			break;
+		}
+		if (map_idx >= nr_maps) {
+			pr_warn("map relo failed to find map for sec %u, off %llu\n",
+				shdr_idx, (__u64)sym->st_value);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+		reloc_desc->type = RELO_LD64;
+		reloc_desc->insn_idx = insn_idx;
+		reloc_desc->map_idx = map_idx;
+		return 0;
+	}
+
+	/* global data map relocation */
+	if (!bpf_object__shndx_is_data(obj, shdr_idx)) {
+		pr_warn("bad data relo against section %u\n", shdr_idx);
+		return -LIBBPF_ERRNO__RELOC;
+	}
+	if (GELF_ST_BIND(sym->st_info) == STB_GLOBAL) {
+		pr_warn("relocation: not yet supported relo for non-static global \'%s\' variable found in insns[%d].code 0x%x\n",
+			name, insn_idx, insn->code);
+		return -LIBBPF_ERRNO__RELOC;
+	}
+	if (!obj->caps.global_data) {
+		pr_warn("relocation: kernel does not support global \'%s\' variable access in insns[%d]\n",
+			name, insn_idx);
+		return -LIBBPF_ERRNO__RELOC;
+	}
+	for (map_idx = 0; map_idx < nr_maps; map_idx++) {
+		map = &obj->maps[map_idx];
+		if (map->libbpf_type != type)
+			continue;
+		pr_debug("found data map %zd (%s, sec %d, off %zu) for insn %u\n",
+			 map_idx, map->name, map->sec_idx, map->sec_offset,
+			 insn_idx);
+		break;
+	}
+	if (map_idx >= nr_maps) {
+		pr_warn("data relo failed to find map for sec %u\n",
+			shdr_idx);
+		return -LIBBPF_ERRNO__RELOC;
+	}
+
+	reloc_desc->type = RELO_DATA;
+	reloc_desc->insn_idx = insn_idx;
+	reloc_desc->map_idx = map_idx;
+	return 0;
+}
+
 static int
 bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
 			   Elf_Data *data, struct bpf_object *obj)
 {
 	Elf_Data *symbols = obj->efile.symbols;
-	struct bpf_map *maps = obj->maps;
-	size_t nr_maps = obj->nr_maps;
-	int i, nrels;
+	int err, i, nrels;
 
 	pr_debug("collecting relocating info for: '%s'\n", prog->section_name);
 	nrels = shdr->sh_size / shdr->sh_entsize;
@@ -1821,12 +1923,8 @@ bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
 	prog->nr_reloc = nrels;
 
 	for (i = 0; i < nrels; i++) {
-		struct bpf_insn *insns = prog->insns;
-		enum libbpf_map_type type;
-		unsigned int insn_idx;
-		unsigned int shdr_idx;
 		const char *name;
-		size_t map_idx;
+		__u32 insn_idx;
 		GElf_Sym sym;
 		GElf_Rel rel;
 
@@ -1834,101 +1932,28 @@ bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
 			pr_warn("relocation: failed to get %d reloc\n", i);
 			return -LIBBPF_ERRNO__FORMAT;
 		}
-
 		if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) {
 			pr_warn("relocation: symbol %"PRIx64" not found\n",
 				GELF_R_SYM(rel.r_info));
 			return -LIBBPF_ERRNO__FORMAT;
 		}
+		if (rel.r_offset % sizeof(struct bpf_insn))
+			return -LIBBPF_ERRNO__FORMAT;
 
+		insn_idx = rel.r_offset / sizeof(struct bpf_insn);
 		name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
 				  sym.st_name) ? : "<?>";
 
-		pr_debug("relo for %lld value %lld name %d (\'%s\')\n",
-			 (long long) (rel.r_info >> 32),
-			 (long long) sym.st_value, sym.st_name, name);
-
-		shdr_idx = sym.st_shndx;
-		insn_idx = rel.r_offset / sizeof(struct bpf_insn);
-		pr_debug("relocation: insn_idx=%u, shdr_idx=%u\n",
-			 insn_idx, shdr_idx);
-
-		if (shdr_idx >= SHN_LORESERVE) {
-			pr_warn("relocation: not yet supported relo for non-static global \'%s\' variable in special section (0x%x) found in insns[%d].code 0x%x\n",
-				name, shdr_idx, insn_idx,
-				insns[insn_idx].code);
-			return -LIBBPF_ERRNO__RELOC;
-		}
-		if (!bpf_object__relo_in_known_section(obj, shdr_idx)) {
-			pr_warn("Program '%s' contains unrecognized relo data pointing to section %u\n",
-				prog->section_name, shdr_idx);
-			return -LIBBPF_ERRNO__RELOC;
-		}
-
-		if (insns[insn_idx].code == (BPF_JMP | BPF_CALL)) {
-			if (insns[insn_idx].src_reg != BPF_PSEUDO_CALL) {
-				pr_warn("incorrect bpf_call opcode\n");
-				return -LIBBPF_ERRNO__RELOC;
-			}
-			if (sym.st_value % 8) {
-				pr_warn("bad call relo offset: %lu\n", sym.st_value);
-				return -LIBBPF_ERRNO__RELOC;
-			}
-			prog->reloc_desc[i].type = RELO_CALL;
-			prog->reloc_desc[i].insn_idx = insn_idx;
-			prog->reloc_desc[i].text_off = sym.st_value / 8;
-			obj->has_pseudo_calls = true;
-			continue;
-		}
-
-		if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
-			pr_warn("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
-				insn_idx, insns[insn_idx].code);
-			return -LIBBPF_ERRNO__RELOC;
-		}
-
-		if (bpf_object__shndx_is_maps(obj, shdr_idx) ||
-		    bpf_object__shndx_is_data(obj, shdr_idx)) {
-			type = bpf_object__section_to_libbpf_map_type(obj, shdr_idx);
-			if (type != LIBBPF_MAP_UNSPEC) {
-				if (GELF_ST_BIND(sym.st_info) == STB_GLOBAL) {
-					pr_warn("bpf: relocation: not yet supported relo for non-static global \'%s\' variable found in insns[%d].code 0x%x\n",
-						name, insn_idx, insns[insn_idx].code);
-					return -LIBBPF_ERRNO__RELOC;
-				}
-				if (!obj->caps.global_data) {
-					pr_warn("bpf: relocation: kernel does not support global \'%s\' variable access in insns[%d]\n",
-						name, insn_idx);
-					return -LIBBPF_ERRNO__RELOC;
-				}
-			}
-
-			for (map_idx = 0; map_idx < nr_maps; map_idx++) {
-				if (maps[map_idx].libbpf_type != type)
-					continue;
-				if (type != LIBBPF_MAP_UNSPEC ||
-				    (maps[map_idx].sec_idx == sym.st_shndx &&
-				     maps[map_idx].sec_offset == sym.st_value)) {
-					pr_debug("relocation: found map %zd (%s, sec_idx %d, offset %zu) for insn %u\n",
-						 map_idx, maps[map_idx].name,
-						 maps[map_idx].sec_idx,
-						 maps[map_idx].sec_offset,
-						 insn_idx);
-					break;
-				}
-			}
-
-			if (map_idx >= nr_maps) {
-				pr_warn("bpf relocation: map_idx %d larger than %d\n",
-					(int)map_idx, (int)nr_maps - 1);
-				return -LIBBPF_ERRNO__RELOC;
-			}
+		pr_debug("relo for shdr %u, symb %llu, value %llu, type %d, bind %d, name %d (\'%s\'), insn %u\n",
+			 (__u32)sym.st_shndx, (__u64)GELF_R_SYM(rel.r_info),
+			 (__u64)sym.st_value, GELF_ST_TYPE(sym.st_info),
+			 GELF_ST_BIND(sym.st_info), sym.st_name, name,
+			 insn_idx);
 
-			prog->reloc_desc[i].type = type != LIBBPF_MAP_UNSPEC ?
-						   RELO_DATA : RELO_LD64;
-			prog->reloc_desc[i].insn_idx = insn_idx;
-			prog->reloc_desc[i].map_idx = map_idx;
-		}
+		err = bpf_program__record_reloc(prog, &prog->reloc_desc[i],
+						insn_idx, name, &sym, &rel);
+		if (err)
+			return err;
 	}
 	return 0;
 }
@@ -3671,9 +3696,9 @@ static int bpf_object__collect_reloc(struct bpf_object *obj)
 		return -LIBBPF_ERRNO__INTERNAL;
 	}
 
-	for (i = 0; i < obj->efile.nr_reloc; i++) {
-		GElf_Shdr *shdr = &obj->efile.reloc[i].shdr;
-		Elf_Data *data = obj->efile.reloc[i].data;
+	for (i = 0; i < obj->efile.nr_reloc_sects; i++) {
+		GElf_Shdr *shdr = &obj->efile.reloc_sects[i].shdr;
+		Elf_Data *data = obj->efile.reloc_sects[i].data;
 		int idx = shdr->sh_info;
 		struct bpf_program *prog;