Commit d147357e authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Martin KaFai Lau
Browse files

libbpf: Allow specifying 64-bit integers in map BTF. 



__uint() macro that is used to specify map attributes like:
  __uint(type, BPF_MAP_TYPE_ARRAY);
  __uint(map_flags, BPF_F_MMAPABLE);
It is limited to 32-bit, since BTF_KIND_ARRAY has u32 "number of elements"
field in "struct btf_array".

Introduce __ulong() macro that allows specifying values bigger than 32-bit.
In map definition "map_extra" is the only u64 field, so far.

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20240307031228.42896-5-alexei.starovoitov@gmail.com


Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
parent cf2c2e4a

tools/lib/bpf/bpf_helpers.h

+1 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#define __uint(name, val) int (*name)[val]

#define __type(name, val) typeof(val) *name

#define __array(name, val) typeof(val) *name[]

#define __ulong(name, val) enum { ___bpf_concat(__unique_value, __COUNTER__) = val } name



/*

 * Helper macro to place programs, maps, license in

tools/lib/bpf/libbpf.c

+42 −2
Original line number Diff line number Diff line
@@ -2335,6 +2335,46 @@ static bool get_map_field_int(const char *map_name, const struct btf *btf, 
	return true;

}



static bool get_map_field_long(const char *map_name, const struct btf *btf,

			       const struct btf_member *m, __u64 *res)

{

	const struct btf_type *t = skip_mods_and_typedefs(btf, m->type, NULL);

	const char *name = btf__name_by_offset(btf, m->name_off);



	if (btf_is_ptr(t)) {

		__u32 res32;

		bool ret;



		ret = get_map_field_int(map_name, btf, m, &res32);

		if (ret)

			*res = (__u64)res32;

		return ret;

	}



	if (!btf_is_enum(t) && !btf_is_enum64(t)) {

		pr_warn("map '%s': attr '%s': expected ENUM or ENUM64, got %s.\n",

			map_name, name, btf_kind_str(t));

		return false;

	}



	if (btf_vlen(t) != 1) {

		pr_warn("map '%s': attr '%s': invalid __ulong\n",

			map_name, name);

		return false;

	}



	if (btf_is_enum(t)) {

		const struct btf_enum *e = btf_enum(t);



		*res = e->val;

	} else {

		const struct btf_enum64 *e = btf_enum64(t);



		*res = btf_enum64_value(e);

	}

	return true;

}



static int pathname_concat(char *buf, size_t buf_sz, const char *path, const char *name)

{

	int len;
@@ -2568,9 +2608,9 @@ int parse_btf_map_def(const char *map_name, struct btf *btf, 
			map_def->pinning = val;

			map_def->parts |= MAP_DEF_PINNING;

		} else if (strcmp(name, "map_extra") == 0) {

			__u32 map_extra;

			__u64 map_extra;



			if (!get_map_field_int(map_name, btf, m, &map_extra))

			if (!get_map_field_long(map_name, btf, m, &map_extra))

				return -EINVAL;

			map_def->map_extra = map_extra;

			map_def->parts |= MAP_DEF_MAP_EXTRA;