libbpf: Put Kconfig externs into .kconfig section (81bfdd08) · Commits · 戴 / test

tools/bpf/bpftool/gen.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -83,8 +83,8 @@ static const char get_map_ident(const struct bpf_map map)
		return "rodata";
		else if (str_has_suffix(name, ".bss"))
		return "bss";
		else if (str_has_suffix(name, ".extern"))
		return "externs"; /* extern is a C keyword */
		else if (str_has_suffix(name, ".kconfig"))
		return "kconfig";
		else
		return NULL;
		}
		@@ -112,8 +112,8 @@ static int codegen_datasec_def(struct bpf_object *obj,
		sec_ident = "bss";
		else if (strcmp(sec_name, ".rodata") == 0)
		sec_ident = "rodata";
		else if (strcmp(sec_name, ".extern") == 0)
		sec_ident = "externs"; /* extern is a C keyword */
		else if (strcmp(sec_name, ".kconfig") == 0)
		sec_ident = "kconfig";
		else
		return 0;

tools/lib/bpf/bpf_helpers.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -53,4 +53,6 @@ enum libbpf_tristate {
		TRI_MODULE = 2,
		};

		#define __kconfig __attribute__((section(".kconfig")))

		#endif

tools/lib/bpf/libbpf.c

+35 −23

Original line number	Diff line number	Diff line
		@@ -231,21 +231,21 @@ struct bpf_program {
		#define DATA_SEC ".data"
		#define BSS_SEC ".bss"
		#define RODATA_SEC ".rodata"
		#define EXTERN_SEC ".extern"
		#define KCONFIG_SEC ".kconfig"

		enum libbpf_map_type {
		LIBBPF_MAP_UNSPEC,
		LIBBPF_MAP_DATA,
		LIBBPF_MAP_BSS,
		LIBBPF_MAP_RODATA,
		LIBBPF_MAP_EXTERN,
		LIBBPF_MAP_KCONFIG,
		};

		static const char * const libbpf_type_to_btf_name[] = {
		[LIBBPF_MAP_DATA] = DATA_SEC,
		[LIBBPF_MAP_BSS] = BSS_SEC,
		[LIBBPF_MAP_RODATA] = RODATA_SEC,
		[LIBBPF_MAP_EXTERN] = EXTERN_SEC,
		[LIBBPF_MAP_KCONFIG] = KCONFIG_SEC,
		};

		struct bpf_map {
		@@ -305,7 +305,7 @@ struct bpf_object {
		char *kconfig_path;
		struct extern_desc *externs;
		int nr_extern;
		int extern_map_idx;
		int kconfig_map_idx;

		bool loaded;
		bool has_pseudo_calls;
		@@ -606,7 +606,7 @@ static struct bpf_object bpf_object__new(const char path,
		obj->efile.data_shndx = -1;
		obj->efile.rodata_shndx = -1;
		obj->efile.bss_shndx = -1;
		obj->extern_map_idx = -1;
		obj->kconfig_map_idx = -1;

		obj->kern_version = get_kernel_version();
		obj->loaded = false;
		@@ -902,11 +902,25 @@ static size_t bpf_map_mmap_sz(const struct bpf_map *map)
		return map_sz;
		}

		static char internal_map_name(struct bpf_object obj,
		enum libbpf_map_type type)
		{
		char map_name[BPF_OBJ_NAME_LEN];
		const char *sfx = libbpf_type_to_btf_name[type];
		int sfx_len = max((size_t)7, strlen(sfx));
		int pfx_len = min((size_t)BPF_OBJ_NAME_LEN - sfx_len - 1,
		strlen(obj->name));

		snprintf(map_name, sizeof(map_name), "%.s%.s", pfx_len, obj->name,
		sfx_len, libbpf_type_to_btf_name[type]);

		return strdup(map_name);
		}

		static int
		bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
		int sec_idx, void *data, size_t data_sz)
		{
		char map_name[BPF_OBJ_NAME_LEN];
		struct bpf_map_def *def;
		struct bpf_map *map;
		int err;
		@@ -918,9 +932,7 @@ bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
		map->libbpf_type = type;
		map->sec_idx = sec_idx;
		map->sec_offset = 0;
		snprintf(map_name, sizeof(map_name), "%.8s%.7s", obj->name,
		libbpf_type_to_btf_name[type]);
		map->name = strdup(map_name);
		map->name = internal_map_name(obj, type);
		if (!map->name) {
		pr_warn("failed to alloc map name\n");
		return -ENOMEM;
		@@ -931,12 +943,12 @@ bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
		def->key_size = sizeof(int);
		def->value_size = data_sz;
		def->max_entries = 1;
		def->map_flags = type == LIBBPF_MAP_RODATA \|\| type == LIBBPF_MAP_EXTERN
		def->map_flags = type == LIBBPF_MAP_RODATA \|\| type == LIBBPF_MAP_KCONFIG
		? BPF_F_RDONLY_PROG : 0;
		def->map_flags \|= BPF_F_MMAPABLE;

		pr_debug("map '%s' (global data): at sec_idx %d, offset %zu, flags %x.\n",
		map_name, map->sec_idx, map->sec_offset, def->map_flags);
		map->name, map->sec_idx, map->sec_offset, def->map_flags);

		map->mmaped = mmap(NULL, bpf_map_mmap_sz(map), PROT_READ \| PROT_WRITE,
		MAP_SHARED \| MAP_ANONYMOUS, -1, 0);
		@@ -1232,7 +1244,7 @@ out:
		return err;
		}

		static int bpf_object__init_extern_map(struct bpf_object *obj)
		static int bpf_object__init_kconfig_map(struct bpf_object *obj)
		{
		struct extern_desc *last_ext;
		size_t map_sz;
		@@ -1244,13 +1256,13 @@ static int bpf_object__init_extern_map(struct bpf_object *obj)
		last_ext = &obj->externs[obj->nr_extern - 1];
		map_sz = last_ext->data_off + last_ext->sz;

		err = bpf_object__init_internal_map(obj, LIBBPF_MAP_EXTERN,
		err = bpf_object__init_internal_map(obj, LIBBPF_MAP_KCONFIG,
		obj->efile.symbols_shndx,
		NULL, map_sz);
		if (err)
		return err;

		obj->extern_map_idx = obj->nr_maps - 1;
		obj->kconfig_map_idx = obj->nr_maps - 1;

		return 0;
		}
		@@ -1742,7 +1754,7 @@ static int bpf_object__init_maps(struct bpf_object *obj,
		err = bpf_object__init_user_maps(obj, strict);
		err = err ?: bpf_object__init_user_btf_maps(obj, strict, pin_root_path);
		err = err ?: bpf_object__init_global_data_maps(obj);
		err = err ?: bpf_object__init_extern_map(obj);
		err = err ?: bpf_object__init_kconfig_map(obj);
		if (err)
		return err;

		@@ -2269,9 +2281,9 @@ static int bpf_object__collect_externs(struct bpf_object *obj)
		i, ext->sym_idx, ext->data_off, ext->name);
		}

		btf_id = btf__find_by_name(obj->btf, EXTERN_SEC);
		btf_id = btf__find_by_name(obj->btf, KCONFIG_SEC);
		if (btf_id <= 0) {
		pr_warn("no BTF info found for '%s' datasec\n", EXTERN_SEC);
		pr_warn("no BTF info found for '%s' datasec\n", KCONFIG_SEC);
		return -ESRCH;
		}

		@@ -2361,7 +2373,7 @@ bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx)
		else if (shndx == obj->efile.rodata_shndx)
		return LIBBPF_MAP_RODATA;
		else if (shndx == obj->efile.symbols_shndx)
		return LIBBPF_MAP_EXTERN;
		return LIBBPF_MAP_KCONFIG;
		else
		return LIBBPF_MAP_UNSPEC;
		}
		@@ -2908,8 +2920,8 @@ bpf_object__populate_internal_map(struct bpf_object obj, struct bpf_map map)
		return err;
		}

		/* Freeze .rodata and .extern map as read-only from syscall side. */
		if (map_type == LIBBPF_MAP_RODATA \|\| map_type == LIBBPF_MAP_EXTERN) {
		/* Freeze .rodata and .kconfig map as read-only from syscall side. */
		if (map_type == LIBBPF_MAP_RODATA \|\| map_type == LIBBPF_MAP_KCONFIG) {
		err = bpf_map_freeze(map->fd);
		if (err) {
		err = -errno;
		@@ -4264,7 +4276,7 @@ bpf_program__relocate(struct bpf_program prog, struct bpf_object obj)
		break;
		case RELO_EXTERN:
		insn[0].src_reg = BPF_PSEUDO_MAP_VALUE;
		insn[0].imm = obj->maps[obj->extern_map_idx].fd;
		insn[0].imm = obj->maps[obj->kconfig_map_idx].fd;
		insn[1].imm = relo->sym_off;
		break;
		case RELO_CALL:
		@@ -4743,7 +4755,7 @@ static int bpf_object__resolve_externs(struct bpf_object *obj,
		if (obj->nr_extern == 0)
		return 0;

		data = obj->maps[obj->extern_map_idx].mmaped;
		data = obj->maps[obj->kconfig_map_idx].mmaped;

		for (i = 0; i < obj->nr_extern; i++) {
		ext = &obj->externs[i];
		@@ -7546,7 +7558,7 @@ int bpf_object__open_skeleton(struct bpf_object_skeleton *s,
		}

		/* externs shouldn't be pre-setup from user code */
		if (mmaped && (*map)->libbpf_type != LIBBPF_MAP_EXTERN)
		if (mmaped && (*map)->libbpf_type != LIBBPF_MAP_KCONFIG)
		mmaped = (map)->mmaped;
		}

tools/testing/selftests/bpf/prog_tests/skeleton.c

+7 −9

Original line number	Diff line number	Diff line
		@@ -15,20 +15,18 @@ void test_skeleton(void)
		int duration = 0, err;
		struct test_skeleton* skel;
		struct test_skeleton__bss *bss;
		struct test_skeleton__externs *exts;
		struct test_skeleton__kconfig *kcfg;

		skel = test_skeleton__open();
		if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
		return;

		printf("EXTERNS BEFORE: %p\n", skel->externs);
		if (CHECK(skel->externs, "skel_externs", "externs are mmaped()!\n"))
		if (CHECK(skel->kconfig, "skel_kconfig", "kconfig is mmaped()!\n"))
		goto cleanup;

		err = test_skeleton__load(skel);
		if (CHECK(err, "skel_load", "failed to load skeleton: %d\n", err))
		goto cleanup;
		printf("EXTERNS AFTER: %p\n", skel->externs);

		bss = skel->bss;
		bss->in1 = 1;
		@@ -37,7 +35,7 @@ void test_skeleton(void)
		bss->in4 = 4;
		bss->in5.a = 5;
		bss->in5.b = 6;
		exts = skel->externs;
		kcfg = skel->kconfig;

		err = test_skeleton__attach(skel);
		if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
		@@ -55,10 +53,10 @@ void test_skeleton(void)
		CHECK(bss->handler_out5.b != 6, "res6", "got %lld != exp %d\n",
		bss->handler_out5.b, 6);

		CHECK(bss->bpf_syscall != exts->CONFIG_BPF_SYSCALL, "ext1",
		"got %d != exp %d\n", bss->bpf_syscall, exts->CONFIG_BPF_SYSCALL);
		CHECK(bss->kern_ver != exts->LINUX_KERNEL_VERSION, "ext2",
		"got %d != exp %d\n", bss->kern_ver, exts->LINUX_KERNEL_VERSION);
		CHECK(bss->bpf_syscall != kcfg->CONFIG_BPF_SYSCALL, "ext1",
		"got %d != exp %d\n", bss->bpf_syscall, kcfg->CONFIG_BPF_SYSCALL);
		CHECK(bss->kern_ver != kcfg->LINUX_KERNEL_VERSION, "ext2",
		"got %d != exp %d\n", bss->kern_ver, kcfg->LINUX_KERNEL_VERSION);

		cleanup:
		test_skeleton__destroy(skel);

tools/testing/selftests/bpf/progs/test_core_extern.c

+10 −10

Original line number	Diff line number	Diff line
		@@ -10,16 +10,16 @@
		/* non-existing BPF helper, to test dead code elimination */
		static int (bpf_missing_helper)(const void arg1, int arg2) = (void *) 999;

		extern int LINUX_KERNEL_VERSION;
		extern bool CONFIG_BPF_SYSCALL; /* strong */
		extern enum libbpf_tristate CONFIG_TRISTATE __weak;
		extern bool CONFIG_BOOL __weak;
		extern char CONFIG_CHAR __weak;
		extern uint16_t CONFIG_USHORT __weak;
		extern int CONFIG_INT __weak;
		extern uint64_t CONFIG_ULONG __weak;
		extern const char CONFIG_STR[8] __weak;
		extern uint64_t CONFIG_MISSING __weak;
		extern int LINUX_KERNEL_VERSION __kconfig;
		extern bool CONFIG_BPF_SYSCALL __kconfig; /* strong */
		extern enum libbpf_tristate CONFIG_TRISTATE __kconfig __weak;
		extern bool CONFIG_BOOL __kconfig __weak;
		extern char CONFIG_CHAR __kconfig __weak;
		extern uint16_t CONFIG_USHORT __kconfig __weak;
		extern int CONFIG_INT __kconfig __weak;
		extern uint64_t CONFIG_ULONG __kconfig __weak;
		extern const char CONFIG_STR[8] __kconfig __weak;
		extern uint64_t CONFIG_MISSING __kconfig __weak;

		uint64_t kern_ver = -1;
		uint64_t bpf_syscall = -1;

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