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Code Issues Releases Wiki Activity

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

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__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: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20240307031228.42896-5-alexei.starovoitov@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
This commit is contained in:
Alexei Starovoitov 2024-03-06 19:12:26 -08:00 committed by Martin KaFai Lau
parent cf2c2e4a3d
commit d147357e2e
2 changed files with 43 additions and 2 deletions
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1
tools/lib/bpf/bpf_helpers.h
View file

@ -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

44
tools/lib/bpf/libbpf.c
View file

@ -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;