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libbpf: Replace btf__type_by_id() with btf_type_by_id(). 

To prepare relo_core.c to be compiled in the kernel and the user space
replace btf__type_by_id with btf_type_by_id.

In libbpf btf__type_by_id and btf_type_by_id have different behavior.

bpf_core_apply_relo_insn() needs behavior of uapi btf__type_by_id
vs internal btf_type_by_id, but type_id range check is already done
in bpf_core_apply_relo(), so it's safe to replace it everywhere.
The kernel btf_type_by_id() does the check anyway. It doesn't hurt.

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211201181040.23337-2-alexei.starovoitov@gmail.com
This commit is contained in:
Alexei Starovoitov 2021-12-01 10:10:24 -08:00 committed by Andrii Nakryiko
parent 64b5b97b8c
commit 74753e1462
3 changed files with 10 additions and 13 deletions
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2
tools/lib/bpf/btf.c
View File

@ -454,7 +454,7 @@ const struct btf *btf__base_btf(const struct btf *btf)
} }
/* internal helper returning non-const pointer to a type */ /* internal helper returning non-const pointer to a type */
struct btf_type *btf_type_by_id(struct btf *btf, __u32 type_id) struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id)
{ {
if (type_id == 0) if (type_id == 0)
return &btf_void; return &btf_void;

2
tools/lib/bpf/libbpf_internal.h
View File

@ -172,7 +172,7 @@ static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size)
struct btf; struct btf;
struct btf_type; struct btf_type;
struct btf_type *btf_type_by_id(struct btf *btf, __u32 type_id); struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id);
const char *btf_kind_str(const struct btf_type *t); const char *btf_kind_str(const struct btf_type *t);
const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id); const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id);

19
tools/lib/bpf/relo_core.c
View File

@ -51,7 +51,7 @@ static bool is_flex_arr(const struct btf *btf,
return false; return false;
/* has to be the last member of enclosing struct */ /* has to be the last member of enclosing struct */
t = btf__type_by_id(btf, acc->type_id); t = btf_type_by_id(btf, acc->type_id);
return acc->idx == btf_vlen(t) - 1; return acc->idx == btf_vlen(t) - 1;
} }
@ -388,7 +388,7 @@ static int bpf_core_match_member(const struct btf *local_btf,
return 0; return 0;
local_id = local_acc->type_id; local_id = local_acc->type_id;
local_type = btf__type_by_id(local_btf, local_id); local_type = btf_type_by_id(local_btf, local_id);
local_member = btf_members(local_type) + local_acc->idx; local_member = btf_members(local_type) + local_acc->idx;
local_name = btf__name_by_offset(local_btf, local_member->name_off); local_name = btf__name_by_offset(local_btf, local_member->name_off);
@ -580,7 +580,7 @@ static int bpf_core_calc_field_relo(const char *prog_name,
return -EUCLEAN; /* request instruction poisoning */ return -EUCLEAN; /* request instruction poisoning */
acc = &spec->spec[spec->len - 1]; acc = &spec->spec[spec->len - 1];
t = btf__type_by_id(spec->btf, acc->type_id); t = btf_type_by_id(spec->btf, acc->type_id);
/* a[n] accessor needs special handling */ /* a[n] accessor needs special handling */
if (!acc->name) { if (!acc->name) {
@ -729,7 +729,7 @@ static int bpf_core_calc_enumval_relo(const struct bpf_core_relo *relo,
case BPF_ENUMVAL_VALUE: case BPF_ENUMVAL_VALUE:
if (!spec) if (!spec)
return -EUCLEAN; /* request instruction poisoning */ return -EUCLEAN; /* request instruction poisoning */
t = btf__type_by_id(spec->btf, spec->spec[0].type_id); t = btf_type_by_id(spec->btf, spec->spec[0].type_id);
e = btf_enum(t) + spec->spec[0].idx; e = btf_enum(t) + spec->spec[0].idx;
*val = e->val; *val = e->val;
break; break;
@ -805,8 +805,8 @@ static int bpf_core_calc_relo(const char *prog_name,
if (res->orig_sz != res->new_sz) { if (res->orig_sz != res->new_sz) {
const struct btf_type *orig_t, *new_t; const struct btf_type *orig_t, *new_t;
orig_t = btf__type_by_id(local_spec->btf, res->orig_type_id); orig_t = btf_type_by_id(local_spec->btf, res->orig_type_id);
new_t = btf__type_by_id(targ_spec->btf, res->new_type_id); new_t = btf_type_by_id(targ_spec->btf, res->new_type_id);
/* There are two use cases in which it's safe to /* There are two use cases in which it's safe to
* adjust load/store's mem size: * adjust load/store's mem size:
@ -1054,7 +1054,7 @@ static void bpf_core_dump_spec(int level, const struct bpf_core_spec *spec)
int i; int i;
type_id = spec->root_type_id; type_id = spec->root_type_id;
t = btf__type_by_id(spec->btf, type_id); t = btf_type_by_id(spec->btf, type_id);
s = btf__name_by_offset(spec->btf, t->name_off); s = btf__name_by_offset(spec->btf, t->name_off);
libbpf_print(level, "[%u] %s %s", type_id, btf_kind_str(t), str_is_empty(s) ? "<anon>" : s); libbpf_print(level, "[%u] %s %s", type_id, btf_kind_str(t), str_is_empty(s) ? "<anon>" : s);
@ -1158,10 +1158,7 @@ int bpf_core_apply_relo_insn(const char *prog_name, struct bpf_insn *insn,
int i, j, err; int i, j, err;
local_id = relo->type_id; local_id = relo->type_id;
local_type = btf__type_by_id(local_btf, local_id); local_type = btf_type_by_id(local_btf, local_id);
if (!local_type)
return -EINVAL;
local_name = btf__name_by_offset(local_btf, local_type->name_off); local_name = btf__name_by_offset(local_btf, local_type->name_off);
if (!local_name) if (!local_name)
return -EINVAL; return -EINVAL;