mirror of https://gitee.com/openkylin/linux.git
libbpf: Refactor CO-RE relocs to not assume a single BTF object
Refactor CO-RE relocation candidate search to not expect a single BTF, rather return all candidate types with their corresponding BTF objects. This will allow to extend CO-RE relocations to accommodate kernel module BTFs. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20201203204634.1325171-5-andrii@kernel.org
This commit is contained in:
Andrii Nakryiko
Alexei Starovoitov
parent
a19f93cfaf
commit
0f7515ca7c
|
|
@ -462,11 +462,14 @@ struct bpf_object {
|
|||
struct list_head list;
|
||||
|
||||
struct btf *btf;
|
||||
struct btf_ext *btf_ext;
|
||||
|
||||
/* Parse and load BTF vmlinux if any of the programs in the object need
|
||||
* it at load time.
|
||||
*/
|
||||
struct btf *btf_vmlinux;
|
||||
struct btf_ext *btf_ext;
|
||||
/* vmlinux BTF override for CO-RE relocations */
|
||||
struct btf *btf_vmlinux_override;
|
||||
|
||||
void *priv;
|
||||
bpf_object_clear_priv_t clear_priv;
|
||||
|
|
@ -4600,46 +4603,43 @@ static size_t bpf_core_essential_name_len(const char *name)
|
|||
return n;
|
||||
}
|
||||
|
||||
/* dynamically sized list of type IDs */
|
||||
struct ids_vec {
|
||||
__u32 *data;
|
||||
struct core_cand
|
||||
{
|
||||
const struct btf *btf;
|
||||
const struct btf_type *t;
|
||||
const char *name;
|
||||
__u32 id;
|
||||
};
|
||||
|
||||
/* dynamically sized list of type IDs and its associated struct btf */
|
||||
struct core_cand_list {
|
||||
struct core_cand *cands;
|
||||
int len;
|
||||
};
|
||||
|
||||
static void bpf_core_free_cands(struct ids_vec *cand_ids)
|
||||
static void bpf_core_free_cands(struct core_cand_list *cands)
|
||||
{
|
||||
free(cand_ids->data);
|
||||
free(cand_ids);
|
||||
free(cands->cands);
|
||||
free(cands);
|
||||
}
|
||||
|
||||
static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf,
|
||||
__u32 local_type_id,
|
||||
const struct btf *targ_btf)
|
||||
static int bpf_core_add_cands(struct core_cand *local_cand,
|
||||
size_t local_essent_len,
|
||||
const struct btf *targ_btf,
|
||||
const char *targ_btf_name,
|
||||
int targ_start_id,
|
||||
struct core_cand_list *cands)
|
||||
{
|
||||
size_t local_essent_len, targ_essent_len;
|
||||
const char *local_name, *targ_name;
|
||||
const struct btf_type *t, *local_t;
|
||||
struct ids_vec *cand_ids;
|
||||
__u32 *new_ids;
|
||||
int i, err, n;
|
||||
|
||||
local_t = btf__type_by_id(local_btf, local_type_id);
|
||||
if (!local_t)
|
||||
return ERR_PTR(-EINVAL);
|
||||
|
||||
local_name = btf__name_by_offset(local_btf, local_t->name_off);
|
||||
if (str_is_empty(local_name))
|
||||
return ERR_PTR(-EINVAL);
|
||||
local_essent_len = bpf_core_essential_name_len(local_name);
|
||||
|
||||
cand_ids = calloc(1, sizeof(*cand_ids));
|
||||
if (!cand_ids)
|
||||
return ERR_PTR(-ENOMEM);
|
||||
struct core_cand *new_cands, *cand;
|
||||
const struct btf_type *t;
|
||||
const char *targ_name;
|
||||
size_t targ_essent_len;
|
||||
int n, i;
|
||||
|
||||
n = btf__get_nr_types(targ_btf);
|
||||
for (i = 1; i <= n; i++) {
|
||||
for (i = targ_start_id; i <= n; i++) {
|
||||
t = btf__type_by_id(targ_btf, i);
|
||||
if (btf_kind(t) != btf_kind(local_t))
|
||||
if (btf_kind(t) != btf_kind(local_cand->t))
|
||||
continue;
|
||||
|
||||
targ_name = btf__name_by_offset(targ_btf, t->name_off);
|
||||
|
|
@ -4650,25 +4650,62 @@ static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf,
|
|||
if (targ_essent_len != local_essent_len)
|
||||
continue;
|
||||
|
||||
if (strncmp(local_name, targ_name, local_essent_len) == 0) {
|
||||
pr_debug("CO-RE relocating [%d] %s %s: found target candidate [%d] %s %s\n",
|
||||
local_type_id, btf_kind_str(local_t),
|
||||
local_name, i, btf_kind_str(t), targ_name);
|
||||
new_ids = libbpf_reallocarray(cand_ids->data,
|
||||
cand_ids->len + 1,
|
||||
sizeof(*cand_ids->data));
|
||||
if (!new_ids) {
|
||||
err = -ENOMEM;
|
||||
goto err_out;
|
||||
}
|
||||
cand_ids->data = new_ids;
|
||||
cand_ids->data[cand_ids->len++] = i;
|
||||
}
|
||||
if (strncmp(local_cand->name, targ_name, local_essent_len) != 0)
|
||||
continue;
|
||||
|
||||
pr_debug("CO-RE relocating [%d] %s %s: found target candidate [%d] %s %s in [%s]\n",
|
||||
local_cand->id, btf_kind_str(local_cand->t),
|
||||
local_cand->name, i, btf_kind_str(t), targ_name,
|
||||
targ_btf_name);
|
||||
new_cands = libbpf_reallocarray(cands->cands, cands->len + 1,
|
||||
sizeof(*cands->cands));
|
||||
if (!new_cands)
|
||||
return -ENOMEM;
|
||||
|
||||
cand = &new_cands[cands->len];
|
||||
cand->btf = targ_btf;
|
||||
cand->t = t;
|
||||
cand->name = targ_name;
|
||||
cand->id = i;
|
||||
|
||||
cands->cands = new_cands;
|
||||
cands->len++;
|
||||
}
|
||||
return cand_ids;
|
||||
err_out:
|
||||
bpf_core_free_cands(cand_ids);
|
||||
return ERR_PTR(err);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static struct core_cand_list *
|
||||
bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 local_type_id)
|
||||
{
|
||||
struct core_cand local_cand = {};
|
||||
struct core_cand_list *cands;
|
||||
size_t local_essent_len;
|
||||
int err;
|
||||
|
||||
local_cand.btf = local_btf;
|
||||
local_cand.t = btf__type_by_id(local_btf, local_type_id);
|
||||
if (!local_cand.t)
|
||||
return ERR_PTR(-EINVAL);
|
||||
|
||||
local_cand.name = btf__name_by_offset(local_btf, local_cand.t->name_off);
|
||||
if (str_is_empty(local_cand.name))
|
||||
return ERR_PTR(-EINVAL);
|
||||
local_essent_len = bpf_core_essential_name_len(local_cand.name);
|
||||
|
||||
cands = calloc(1, sizeof(*cands));
|
||||
if (!cands)
|
||||
return ERR_PTR(-ENOMEM);
|
||||
|
||||
/* Attempt to find target candidates in vmlinux BTF first */
|
||||
err = bpf_core_add_cands(&local_cand, local_essent_len,
|
||||
obj->btf_vmlinux_override ?: obj->btf_vmlinux,
|
||||
"vmlinux", 1, cands);
|
||||
if (err) {
|
||||
bpf_core_free_cands(cands);
|
||||
return ERR_PTR(err);
|
||||
}
|
||||
|
||||
return cands;
|
||||
}
|
||||
|
||||
/* Check two types for compatibility for the purpose of field access
|
||||
|
|
@ -5661,7 +5698,6 @@ static int bpf_core_apply_relo(struct bpf_program *prog,
|
|||
const struct bpf_core_relo *relo,
|
||||
int relo_idx,
|
||||
const struct btf *local_btf,
|
||||
const struct btf *targ_btf,
|
||||
struct hashmap *cand_cache)
|
||||
{
|
||||
struct bpf_core_spec local_spec, cand_spec, targ_spec = {};
|
||||
|
|
@ -5669,8 +5705,8 @@ static int bpf_core_apply_relo(struct bpf_program *prog,
|
|||
struct bpf_core_relo_res cand_res, targ_res;
|
||||
const struct btf_type *local_type;
|
||||
const char *local_name;
|
||||
struct ids_vec *cand_ids;
|
||||
__u32 local_id, cand_id;
|
||||
struct core_cand_list *cands = NULL;
|
||||
__u32 local_id;
|
||||
const char *spec_str;
|
||||
int i, j, err;
|
||||
|
||||
|
|
@ -5717,24 +5753,24 @@ static int bpf_core_apply_relo(struct bpf_program *prog,
|
|||
return -EOPNOTSUPP;
|
||||
}
|
||||
|
||||
if (!hashmap__find(cand_cache, type_key, (void **)&cand_ids)) {
|
||||
cand_ids = bpf_core_find_cands(local_btf, local_id, targ_btf);
|
||||
if (IS_ERR(cand_ids)) {
|
||||
if (!hashmap__find(cand_cache, type_key, (void **)&cands)) {
|
||||
cands = bpf_core_find_cands(prog->obj, local_btf, local_id);
|
||||
if (IS_ERR(cands)) {
|
||||
pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld",
|
||||
prog->name, relo_idx, local_id, btf_kind_str(local_type),
|
||||
local_name, PTR_ERR(cand_ids));
|
||||
return PTR_ERR(cand_ids);
|
||||
local_name, PTR_ERR(cands));
|
||||
return PTR_ERR(cands);
|
||||
}
|
||||
err = hashmap__set(cand_cache, type_key, cand_ids, NULL, NULL);
|
||||
err = hashmap__set(cand_cache, type_key, cands, NULL, NULL);
|
||||
if (err) {
|
||||
bpf_core_free_cands(cand_ids);
|
||||
bpf_core_free_cands(cands);
|
||||
return err;
|
||||
}
|
||||
}
|
||||
|
||||
for (i = 0, j = 0; i < cand_ids->len; i++) {
|
||||
cand_id = cand_ids->data[i];
|
||||
err = bpf_core_spec_match(&local_spec, targ_btf, cand_id, &cand_spec);
|
||||
for (i = 0, j = 0; i < cands->len; i++) {
|
||||
err = bpf_core_spec_match(&local_spec, cands->cands[i].btf,
|
||||
cands->cands[i].id, &cand_spec);
|
||||
if (err < 0) {
|
||||
pr_warn("prog '%s': relo #%d: error matching candidate #%d ",
|
||||
prog->name, relo_idx, i);
|
||||
|
|
@ -5778,7 +5814,7 @@ static int bpf_core_apply_relo(struct bpf_program *prog,
|
|||
return -EINVAL;
|
||||
}
|
||||
|
||||
cand_ids->data[j++] = cand_spec.root_type_id;
|
||||
cands->cands[j++] = cands->cands[i];
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
@ -5790,7 +5826,7 @@ static int bpf_core_apply_relo(struct bpf_program *prog,
|
|||
* depending on relo's kind.
|
||||
*/
|
||||
if (j > 0)
|
||||
cand_ids->len = j;
|
||||
cands->len = j;
|
||||
|
||||
/*
|
||||
* If no candidates were found, it might be both a programmer error,
|
||||
|
|
@ -5834,20 +5870,19 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
|
|||
struct hashmap_entry *entry;
|
||||
struct hashmap *cand_cache = NULL;
|
||||
struct bpf_program *prog;
|
||||
struct btf *targ_btf;
|
||||
const char *sec_name;
|
||||
int i, err = 0, insn_idx, sec_idx;
|
||||
|
||||
if (obj->btf_ext->core_relo_info.len == 0)
|
||||
return 0;
|
||||
|
||||
if (targ_btf_path)
|
||||
targ_btf = btf__parse(targ_btf_path, NULL);
|
||||
else
|
||||
targ_btf = obj->btf_vmlinux;
|
||||
if (IS_ERR_OR_NULL(targ_btf)) {
|
||||
pr_warn("failed to get target BTF: %ld\n", PTR_ERR(targ_btf));
|
||||
return PTR_ERR(targ_btf);
|
||||
if (targ_btf_path) {
|
||||
obj->btf_vmlinux_override = btf__parse(targ_btf_path, NULL);
|
||||
if (IS_ERR_OR_NULL(obj->btf_vmlinux_override)) {
|
||||
err = PTR_ERR(obj->btf_vmlinux_override);
|
||||
pr_warn("failed to parse target BTF: %d\n", err);
|
||||
return err;
|
||||
}
|
||||
}
|
||||
|
||||
cand_cache = hashmap__new(bpf_core_hash_fn, bpf_core_equal_fn, NULL);
|
||||
|
|
@ -5899,8 +5934,7 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
|
|||
if (!prog->load)
|
||||
continue;
|
||||
|
||||
err = bpf_core_apply_relo(prog, rec, i, obj->btf,
|
||||
targ_btf, cand_cache);
|
||||
err = bpf_core_apply_relo(prog, rec, i, obj->btf, cand_cache);
|
||||
if (err) {
|
||||
pr_warn("prog '%s': relo #%d: failed to relocate: %d\n",
|
||||
prog->name, i, err);
|
||||
|
|
@ -5911,8 +5945,9 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
|
|||
|
||||
out:
|
||||
/* obj->btf_vmlinux is freed at the end of object load phase */
|
||||
if (targ_btf != obj->btf_vmlinux)
|
||||
btf__free(targ_btf);
|
||||
btf__free(obj->btf_vmlinux_override);
|
||||
obj->btf_vmlinux_override = NULL;
|
||||
|
||||
if (!IS_ERR_OR_NULL(cand_cache)) {
|
||||
hashmap__for_each_entry(cand_cache, entry, i) {
|
||||
bpf_core_free_cands(entry->value);
|
||||
|
|
|
|||
Loading…
Reference in New Issue