From: Hengqi Chen <hengqi.chen@gmail.com>
Date: Sun, 28 Nov 2021 22:16:32 +0800
Subject: libbpf: Support static initialization of BPF_MAP_TYPE_PROG_ARRAY
Patch-mainline: v5.17-rc1
Git-commit: 341ac5ffc4bd859103899c876902caf07cc97ea4
References: jsc#PED-1368
Support static initialization of BPF_MAP_TYPE_PROG_ARRAY with a
syntax similar to map-in-map initialization ([0]):
SEC("socket")
int tailcall_1(void *ctx)
{
return 0;
}
struct {
__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
__uint(max_entries, 2);
__uint(key_size, sizeof(__u32));
__array(values, int (void *));
} prog_array_init SEC(".maps") = {
.values = {
[1] = (void *)&tailcall_1,
},
};
Here's the relevant part of libbpf debug log showing what's
going on with prog-array initialization:
libbpf: sec '.relsocket': collecting relocation for section(3) 'socket'
libbpf: sec '.relsocket': relo #0: insn #2 against 'prog_array_init'
libbpf: prog 'entry': found map 0 (prog_array_init, sec 4, off 0) for insn #0
libbpf: .maps relo #0: for 3 value 0 rel->r_offset 32 name 53 ('tailcall_1')
libbpf: .maps relo #0: map 'prog_array_init' slot [1] points to prog 'tailcall_1'
libbpf: map 'prog_array_init': created successfully, fd=5
libbpf: map 'prog_array_init': slot [1] set to prog 'tailcall_1' fd=6
[0] Closes: https://github.com/libbpf/libbpf/issues/354
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211128141633.502339-2-hengqi.chen@gmail.com
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
tools/lib/bpf/libbpf.c | 154 ++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 121 insertions(+), 33 deletions(-)
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2277,6 +2277,9 @@ int parse_btf_map_def(const char *map_na
map_def->parts |= MAP_DEF_VALUE_SIZE | MAP_DEF_VALUE_TYPE;
}
else if (strcmp(name, "values") == 0) {
+ bool is_map_in_map = bpf_map_type__is_map_in_map(map_def->map_type);
+ bool is_prog_array = map_def->map_type == BPF_MAP_TYPE_PROG_ARRAY;
+ const char *desc = is_map_in_map ? "map-in-map inner" : "prog-array value";
char inner_map_name[128];
int err;
@@ -2290,8 +2293,8 @@ int parse_btf_map_def(const char *map_na
map_name, name);
return -EINVAL;
}
- if (!bpf_map_type__is_map_in_map(map_def->map_type)) {
- pr_warn("map '%s': should be map-in-map.\n",
+ if (!is_map_in_map && !is_prog_array) {
+ pr_warn("map '%s': should be map-in-map or prog-array.\n",
map_name);
return -ENOTSUP;
}
@@ -2303,22 +2306,30 @@ int parse_btf_map_def(const char *map_na
map_def->value_size = 4;
t = btf__type_by_id(btf, m->type);
if (!t) {
- pr_warn("map '%s': map-in-map inner type [%d] not found.\n",
- map_name, m->type);
+ pr_warn("map '%s': %s type [%d] not found.\n",
+ map_name, desc, m->type);
return -EINVAL;
}
if (!btf_is_array(t) || btf_array(t)->nelems) {
- pr_warn("map '%s': map-in-map inner spec is not a zero-sized array.\n",
- map_name);
+ pr_warn("map '%s': %s spec is not a zero-sized array.\n",
+ map_name, desc);
return -EINVAL;
}
t = skip_mods_and_typedefs(btf, btf_array(t)->type, NULL);
if (!btf_is_ptr(t)) {
- pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n",
- map_name, btf_kind_str(t));
+ pr_warn("map '%s': %s def is of unexpected kind %s.\n",
+ map_name, desc, btf_kind_str(t));
return -EINVAL;
}
t = skip_mods_and_typedefs(btf, t->type, NULL);
+ if (is_prog_array) {
+ if (!btf_is_func_proto(t)) {
+ pr_warn("map '%s': prog-array value def is of unexpected kind %s.\n",
+ map_name, btf_kind_str(t));
+ return -EINVAL;
+ }
+ continue;
+ }
if (!btf_is_struct(t)) {
pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n",
map_name, btf_kind_str(t));
@@ -4940,7 +4951,7 @@ static int bpf_object__create_map(struct
return err;
}
-static int init_map_slots(struct bpf_object *obj, struct bpf_map *map)
+static int init_map_in_map_slots(struct bpf_object *obj, struct bpf_map *map)
{
const struct bpf_map *targ_map;
unsigned int i;
@@ -4952,6 +4963,7 @@ static int init_map_slots(struct bpf_obj
targ_map = map->init_slots[i];
fd = bpf_map__fd(targ_map);
+
if (obj->gen_loader) {
pr_warn("// TODO map_update_elem: idx %td key %d value==map_idx %td\n",
map - obj->maps, i, targ_map - obj->maps);
@@ -4962,8 +4974,7 @@ static int init_map_slots(struct bpf_obj
if (err) {
err = -errno;
pr_warn("map '%s': failed to initialize slot [%d] to map '%s' fd=%d: %d\n",
- map->name, i, targ_map->name,
- fd, err);
+ map->name, i, targ_map->name, fd, err);
return err;
}
pr_debug("map '%s': slot [%d] set to map '%s' fd=%d\n",
@@ -4976,6 +4987,59 @@ static int init_map_slots(struct bpf_obj
return 0;
}
+static int init_prog_array_slots(struct bpf_object *obj, struct bpf_map *map)
+{
+ const struct bpf_program *targ_prog;
+ unsigned int i;
+ int fd, err;
+
+ if (obj->gen_loader)
+ return -ENOTSUP;
+
+ for (i = 0; i < map->init_slots_sz; i++) {
+ if (!map->init_slots[i])
+ continue;
+
+ targ_prog = map->init_slots[i];
+ fd = bpf_program__fd(targ_prog);
+
+ err = bpf_map_update_elem(map->fd, &i, &fd, 0);
+ if (err) {
+ err = -errno;
+ pr_warn("map '%s': failed to initialize slot [%d] to prog '%s' fd=%d: %d\n",
+ map->name, i, targ_prog->name, fd, err);
+ return err;
+ }
+ pr_debug("map '%s': slot [%d] set to prog '%s' fd=%d\n",
+ map->name, i, targ_prog->name, fd);
+ }
+
+ zfree(&map->init_slots);
+ map->init_slots_sz = 0;
+
+ return 0;
+}
+
+static int bpf_object_init_prog_arrays(struct bpf_object *obj)
+{
+ struct bpf_map *map;
+ int i, err;
+
+ for (i = 0; i < obj->nr_maps; i++) {
+ map = &obj->maps[i];
+
+ if (!map->init_slots_sz || map->def.type != BPF_MAP_TYPE_PROG_ARRAY)
+ continue;
+
+ err = init_prog_array_slots(obj, map);
+ if (err < 0) {
+ zclose(map->fd);
+ return err;
+ }
+ }
+ return 0;
+}
+
static int
bpf_object__create_maps(struct bpf_object *obj)
{
@@ -5042,8 +5106,8 @@ retry:
}
}
- if (map->init_slots_sz) {
- err = init_map_slots(obj, map);
+ if (map->init_slots_sz && map->def.type != BPF_MAP_TYPE_PROG_ARRAY) {
+ err = init_map_in_map_slots(obj, map);
if (err < 0) {
zclose(map->fd);
goto err_out;
@@ -6189,9 +6253,11 @@ static int bpf_object__collect_map_relos
int i, j, nrels, new_sz;
const struct btf_var_secinfo *vi = NULL;
const struct btf_type *sec, *var, *def;
- struct bpf_map *map = NULL, *targ_map;
+ struct bpf_map *map = NULL, *targ_map = NULL;
+ struct bpf_program *targ_prog = NULL;
+ bool is_prog_array, is_map_in_map;
const struct btf_member *member;
- const char *name, *mname;
+ const char *name, *mname, *type;
unsigned int moff;
Elf64_Sym *sym;
Elf64_Rel *rel;
@@ -6218,11 +6284,6 @@ static int bpf_object__collect_map_relos
return -LIBBPF_ERRNO__FORMAT;
}
name = elf_sym_str(obj, sym->st_name) ?: "<?>";
- if (sym->st_shndx != obj->efile.btf_maps_shndx) {
- pr_warn(".maps relo #%d: '%s' isn't a BTF-defined map\n",
- i, name);
- return -LIBBPF_ERRNO__RELOC;
- }
pr_debug(".maps relo #%d: for %zd value %zd rel->r_offset %zu name %d ('%s')\n",
i, (ssize_t)(rel->r_info >> 32), (size_t)sym->st_value,
@@ -6244,19 +6305,45 @@ static int bpf_object__collect_map_relos
return -EINVAL;
}
- if (!bpf_map_type__is_map_in_map(map->def.type))
- return -EINVAL;
- if (map->def.type == BPF_MAP_TYPE_HASH_OF_MAPS &&
- map->def.key_size != sizeof(int)) {
- pr_warn(".maps relo #%d: hash-of-maps '%s' should have key size %zu.\n",
- i, map->name, sizeof(int));
+ is_map_in_map = bpf_map_type__is_map_in_map(map->def.type);
+ is_prog_array = map->def.type == BPF_MAP_TYPE_PROG_ARRAY;
+ type = is_map_in_map ? "map" : "prog";
+ if (is_map_in_map) {
+ if (sym->st_shndx != obj->efile.btf_maps_shndx) {
+ pr_warn(".maps relo #%d: '%s' isn't a BTF-defined map\n",
+ i, name);
+ return -LIBBPF_ERRNO__RELOC;
+ }
+ if (map->def.type == BPF_MAP_TYPE_HASH_OF_MAPS &&
+ map->def.key_size != sizeof(int)) {
+ pr_warn(".maps relo #%d: hash-of-maps '%s' should have key size %zu.\n",
+ i, map->name, sizeof(int));
+ return -EINVAL;
+ }
+ targ_map = bpf_object__find_map_by_name(obj, name);
+ if (!targ_map) {
+ pr_warn(".maps relo #%d: '%s' isn't a valid map reference\n",
+ i, name);
+ return -ESRCH;
+ }
+ } else if (is_prog_array) {
+ targ_prog = bpf_object__find_program_by_name(obj, name);
+ if (!targ_prog) {
+ pr_warn(".maps relo #%d: '%s' isn't a valid program reference\n",
+ i, name);
+ return -ESRCH;
+ }
+ if (targ_prog->sec_idx != sym->st_shndx ||
+ targ_prog->sec_insn_off * 8 != sym->st_value ||
+ prog_is_subprog(obj, targ_prog)) {
+ pr_warn(".maps relo #%d: '%s' isn't an entry-point program\n",
+ i, name);
+ return -LIBBPF_ERRNO__RELOC;
+ }
+ } else {
return -EINVAL;
}
- targ_map = bpf_object__find_map_by_name(obj, name);
- if (!targ_map)
- return -ESRCH;
-
var = btf__type_by_id(obj->btf, vi->type);
def = skip_mods_and_typedefs(obj->btf, var->type, NULL);
if (btf_vlen(def) == 0)
@@ -6287,10 +6374,10 @@ static int bpf_object__collect_map_relos
(new_sz - map->init_slots_sz) * host_ptr_sz);
map->init_slots_sz = new_sz;
}
- map->init_slots[moff] = targ_map;
+ map->init_slots[moff] = is_map_in_map ? (void *)targ_map : (void *)targ_prog;
- pr_debug(".maps relo #%d: map '%s' slot [%d] points to map '%s'\n",
- i, map->name, moff, name);
+ pr_debug(".maps relo #%d: map '%s' slot [%d] points to %s '%s'\n",
+ i, map->name, moff, type, name);
}
return 0;
@@ -7302,6 +7389,7 @@ int bpf_object__load_xattr(struct bpf_ob
err = err ? : bpf_object__create_maps(obj);
err = err ? : bpf_object__relocate(obj, obj->btf_custom_path ? : attr->target_btf_path);
err = err ? : bpf_object__load_progs(obj, attr->log_level);
+ err = err ? : bpf_object_init_prog_arrays(obj);
if (obj->gen_loader) {
/* reset FDs */