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Diffstat (limited to 'tools/lib/bpf/libbpf.c')
-rw-r--r--tools/lib/bpf/libbpf.c169
1 files changed, 105 insertions, 64 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index a02cdedc4e3f0..8d565590ce059 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -249,6 +249,7 @@ struct bpf_object {
bool loaded;
bool has_pseudo_calls;
+ bool relaxed_core_relocs;
/*
* Information when doing elf related work. Only valid if fd
@@ -1322,9 +1323,9 @@ static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict)
return 0;
}
-static int bpf_object__init_maps(struct bpf_object *obj, int flags)
+static int bpf_object__init_maps(struct bpf_object *obj, bool relaxed_maps)
{
- bool strict = !(flags & MAPS_RELAX_COMPAT);
+ bool strict = !relaxed_maps;
int err;
err = bpf_object__init_user_maps(obj, strict);
@@ -1521,7 +1522,7 @@ static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj)
return 0;
}
-static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
+static int bpf_object__elf_collect(struct bpf_object *obj, bool relaxed_maps)
{
Elf *elf = obj->efile.elf;
GElf_Ehdr *ep = &obj->efile.ehdr;
@@ -1652,7 +1653,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
}
err = bpf_object__init_btf(obj, btf_data, btf_ext_data);
if (!err)
- err = bpf_object__init_maps(obj, flags);
+ err = bpf_object__init_maps(obj, relaxed_maps);
if (!err)
err = bpf_object__sanitize_and_load_btf(obj);
if (!err)
@@ -2326,7 +2327,7 @@ static bool str_is_empty(const char *s)
}
/*
- * Turn bpf_offset_reloc into a low- and high-level spec representation,
+ * Turn bpf_field_reloc into a low- and high-level spec representation,
* validating correctness along the way, as well as calculating resulting
* field offset (in bytes), specified by accessor string. Low-level spec
* captures every single level of nestedness, including traversing anonymous
@@ -2771,26 +2772,54 @@ static int bpf_core_spec_match(struct bpf_core_spec *local_spec,
/*
* Patch relocatable BPF instruction.
- * Expected insn->imm value is provided for validation, as well as the new
- * relocated value.
+ *
+ * Patched value is determined by relocation kind and target specification.
+ * For field existence relocation target spec will be NULL if field is not
+ * found.
+ * Expected insn->imm value is determined using relocation kind and local
+ * spec, and is checked before patching instruction. If actual insn->imm value
+ * is wrong, bail out with error.
*
* Currently three kinds of BPF instructions are supported:
* 1. rX = <imm> (assignment with immediate operand);
* 2. rX += <imm> (arithmetic operations with immediate operand);
- * 3. *(rX) = <imm> (indirect memory assignment with immediate operand).
- *
- * If actual insn->imm value is wrong, bail out.
*/
-static int bpf_core_reloc_insn(struct bpf_program *prog, int insn_off,
- __u32 orig_off, __u32 new_off)
+static int bpf_core_reloc_insn(struct bpf_program *prog,
+ const struct bpf_field_reloc *relo,
+ const struct bpf_core_spec *local_spec,
+ const struct bpf_core_spec *targ_spec)
{
+ __u32 orig_val, new_val;
struct bpf_insn *insn;
int insn_idx;
__u8 class;
- if (insn_off % sizeof(struct bpf_insn))
+ if (relo->insn_off % sizeof(struct bpf_insn))
+ return -EINVAL;
+ insn_idx = relo->insn_off / sizeof(struct bpf_insn);
+
+ switch (relo->kind) {
+ case BPF_FIELD_BYTE_OFFSET:
+ orig_val = local_spec->offset;
+ if (targ_spec) {
+ new_val = targ_spec->offset;
+ } else {
+ pr_warning("prog '%s': patching insn #%d w/ failed reloc, imm %d -> %d\n",
+ bpf_program__title(prog, false), insn_idx,
+ orig_val, -1);
+ new_val = (__u32)-1;
+ }
+ break;
+ case BPF_FIELD_EXISTS:
+ orig_val = 1; /* can't generate EXISTS relo w/o local field */
+ new_val = targ_spec ? 1 : 0;
+ break;
+ default:
+ pr_warning("prog '%s': unknown relo %d at insn #%d'\n",
+ bpf_program__title(prog, false),
+ relo->kind, insn_idx);
return -EINVAL;
- insn_idx = insn_off / sizeof(struct bpf_insn);
+ }
insn = &prog->insns[insn_idx];
class = BPF_CLASS(insn->code);
@@ -2798,12 +2827,12 @@ static int bpf_core_reloc_insn(struct bpf_program *prog, int insn_off,
if (class == BPF_ALU || class == BPF_ALU64) {
if (BPF_SRC(insn->code) != BPF_K)
return -EINVAL;
- if (insn->imm != orig_off)
+ if (insn->imm != orig_val)
return -EINVAL;
- insn->imm = new_off;
+ insn->imm = new_val;
pr_debug("prog '%s': patched insn #%d (ALU/ALU64) imm %d -> %d\n",
bpf_program__title(prog, false),
- insn_idx, orig_off, new_off);
+ insn_idx, orig_val, new_val);
} else {
pr_warning("prog '%s': trying to relocate unrecognized insn #%d, code:%x, src:%x, dst:%x, off:%x, imm:%x\n",
bpf_program__title(prog, false),
@@ -2811,6 +2840,7 @@ static int bpf_core_reloc_insn(struct bpf_program *prog, int insn_off,
insn->off, insn->imm);
return -EINVAL;
}
+
return 0;
}
@@ -2977,7 +3007,7 @@ static void *u32_as_hash_key(__u32 x)
* types should be compatible (see bpf_core_fields_are_compat for details).
* 3. It is supported and expected that there might be multiple flavors
* matching the spec. As long as all the specs resolve to the same set of
- * offsets across all candidates, there is not error. If there is any
+ * offsets across all candidates, there is no error. If there is any
* ambiguity, CO-RE relocation will fail. This is necessary to accomodate
* imprefection of BTF deduplication, which can cause slight duplication of
* the same BTF type, if some directly or indirectly referenced (by
@@ -2992,12 +3022,12 @@ static void *u32_as_hash_key(__u32 x)
* CPU-wise compared to prebuilding a map from all local type names to
* a list of candidate type names. It's also sped up by caching resolved
* list of matching candidates per each local "root" type ID, that has at
- * least one bpf_offset_reloc associated with it. This list is shared
+ * least one bpf_field_reloc associated with it. This list is shared
* between multiple relocations for the same type ID and is updated as some
* of the candidates are pruned due to structural incompatibility.
*/
-static int bpf_core_reloc_offset(struct bpf_program *prog,
- const struct bpf_offset_reloc *relo,
+static int bpf_core_reloc_field(struct bpf_program *prog,
+ const struct bpf_field_reloc *relo,
int relo_idx,
const struct btf *local_btf,
const struct btf *targ_btf,
@@ -3087,15 +3117,26 @@ static int bpf_core_reloc_offset(struct bpf_program *prog,
cand_ids->data[j++] = cand_spec.spec[0].type_id;
}
- cand_ids->len = j;
- if (cand_ids->len == 0) {
+ /*
+ * For BPF_FIELD_EXISTS relo or when relaxed CO-RE reloc mode is
+ * requested, it's expected that we might not find any candidates.
+ * In this case, if field wasn't found in any candidate, the list of
+ * candidates shouldn't change at all, we'll just handle relocating
+ * appropriately, depending on relo's kind.
+ */
+ if (j > 0)
+ cand_ids->len = j;
+
+ if (j == 0 && !prog->obj->relaxed_core_relocs &&
+ relo->kind != BPF_FIELD_EXISTS) {
pr_warning("prog '%s': relo #%d: no matching targets found for [%d] %s + %s\n",
prog_name, relo_idx, local_id, local_name, spec_str);
return -ESRCH;
}
- err = bpf_core_reloc_insn(prog, relo->insn_off,
- local_spec.offset, targ_spec.offset);
+ /* bpf_core_reloc_insn should know how to handle missing targ_spec */
+ err = bpf_core_reloc_insn(prog, relo, &local_spec,
+ j ? &targ_spec : NULL);
if (err) {
pr_warning("prog '%s': relo #%d: failed to patch insn at offset %d: %d\n",
prog_name, relo_idx, relo->insn_off, err);
@@ -3106,10 +3147,10 @@ static int bpf_core_reloc_offset(struct bpf_program *prog,
}
static int
-bpf_core_reloc_offsets(struct bpf_object *obj, const char *targ_btf_path)
+bpf_core_reloc_fields(struct bpf_object *obj, const char *targ_btf_path)
{
const struct btf_ext_info_sec *sec;
- const struct bpf_offset_reloc *rec;
+ const struct bpf_field_reloc *rec;
const struct btf_ext_info *seg;
struct hashmap_entry *entry;
struct hashmap *cand_cache = NULL;
@@ -3134,7 +3175,7 @@ bpf_core_reloc_offsets(struct bpf_object *obj, const char *targ_btf_path)
goto out;
}
- seg = &obj->btf_ext->offset_reloc_info;
+ seg = &obj->btf_ext->field_reloc_info;
for_each_btf_ext_sec(seg, sec) {
sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off);
if (str_is_empty(sec_name)) {
@@ -3153,8 +3194,8 @@ bpf_core_reloc_offsets(struct bpf_object *obj, const char *targ_btf_path)
sec_name, sec->num_info);
for_each_btf_ext_rec(seg, sec, i, rec) {
- err = bpf_core_reloc_offset(prog, rec, i, obj->btf,
- targ_btf, cand_cache);
+ err = bpf_core_reloc_field(prog, rec, i, obj->btf,
+ targ_btf, cand_cache);
if (err) {
pr_warning("prog '%s': relo #%d: failed to relocate: %d\n",
sec_name, i, err);
@@ -3179,8 +3220,8 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
{
int err = 0;
- if (obj->btf_ext->offset_reloc_info.len)
- err = bpf_core_reloc_offsets(obj, targ_btf_path);
+ if (obj->btf_ext->field_reloc_info.len)
+ err = bpf_core_reloc_fields(obj, targ_btf_path);
return err;
}
@@ -3554,24 +3595,46 @@ bpf_object__load_progs(struct bpf_object *obj, int log_level)
static struct bpf_object *
__bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
- const char *obj_name, int flags)
+ struct bpf_object_open_opts *opts)
{
struct bpf_object *obj;
+ const char *obj_name;
+ char tmp_name[64];
+ bool relaxed_maps;
int err;
if (elf_version(EV_CURRENT) == EV_NONE) {
- pr_warning("failed to init libelf for %s\n", path);
+ pr_warning("failed to init libelf for %s\n",
+ path ? : "(mem buf)");
return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
}
+ if (!OPTS_VALID(opts, bpf_object_open_opts))
+ return ERR_PTR(-EINVAL);
+
+ obj_name = OPTS_GET(opts, object_name, path);
+ if (obj_buf) {
+ if (!obj_name) {
+ snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
+ (unsigned long)obj_buf,
+ (unsigned long)obj_buf_sz);
+ obj_name = tmp_name;
+ }
+ path = obj_name;
+ pr_debug("loading object '%s' from buffer\n", obj_name);
+ }
+
obj = bpf_object__new(path, obj_buf, obj_buf_sz, obj_name);
if (IS_ERR(obj))
return obj;
+ obj->relaxed_core_relocs = OPTS_GET(opts, relaxed_core_relocs, false);
+ relaxed_maps = OPTS_GET(opts, relaxed_maps, false);
+
CHECK_ERR(bpf_object__elf_init(obj), err, out);
CHECK_ERR(bpf_object__check_endianness(obj), err, out);
CHECK_ERR(bpf_object__probe_caps(obj), err, out);
- CHECK_ERR(bpf_object__elf_collect(obj, flags), err, out);
+ CHECK_ERR(bpf_object__elf_collect(obj, relaxed_maps), err, out);
CHECK_ERR(bpf_object__collect_reloc(obj), err, out);
bpf_object__elf_finish(obj);
@@ -3584,13 +3647,16 @@ out:
static struct bpf_object *
__bpf_object__open_xattr(struct bpf_object_open_attr *attr, int flags)
{
+ LIBBPF_OPTS(bpf_object_open_opts, opts,
+ .relaxed_maps = flags & MAPS_RELAX_COMPAT,
+ );
+
/* param validation */
if (!attr->file)
return NULL;
pr_debug("loading %s\n", attr->file);
-
- return __bpf_object__open(attr->file, NULL, 0, NULL, flags);
+ return __bpf_object__open(attr->file, NULL, 0, &opts);
}
struct bpf_object *bpf_object__open_xattr(struct bpf_object_open_attr *attr)
@@ -3611,47 +3677,22 @@ struct bpf_object *bpf_object__open(const char *path)
struct bpf_object *
bpf_object__open_file(const char *path, struct bpf_object_open_opts *opts)
{
- const char *obj_name;
- bool relaxed_maps;
-
- if (!OPTS_VALID(opts, bpf_object_open_opts))
- return ERR_PTR(-EINVAL);
if (!path)
return ERR_PTR(-EINVAL);
pr_debug("loading %s\n", path);
- obj_name = OPTS_GET(opts, object_name, path);
- relaxed_maps = OPTS_GET(opts, relaxed_maps, false);
- return __bpf_object__open(path, NULL, 0, obj_name,
- relaxed_maps ? MAPS_RELAX_COMPAT : 0);
+ return __bpf_object__open(path, NULL, 0, opts);
}
struct bpf_object *
bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz,
struct bpf_object_open_opts *opts)
{
- char tmp_name[64];
- const char *obj_name;
- bool relaxed_maps;
-
- if (!OPTS_VALID(opts, bpf_object_open_opts))
- return ERR_PTR(-EINVAL);
if (!obj_buf || obj_buf_sz == 0)
return ERR_PTR(-EINVAL);
- obj_name = OPTS_GET(opts, object_name, NULL);
- if (!obj_name) {
- snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
- (unsigned long)obj_buf,
- (unsigned long)obj_buf_sz);
- obj_name = tmp_name;
- }
- pr_debug("loading object '%s' from buffer\n", obj_name);
-
- relaxed_maps = OPTS_GET(opts, relaxed_maps, false);
- return __bpf_object__open(obj_name, obj_buf, obj_buf_sz, obj_name,
- relaxed_maps ? MAPS_RELAX_COMPAT : 0);
+ return __bpf_object__open(NULL, obj_buf, obj_buf_sz, opts);
}
struct bpf_object *
generated by cgit v1.2.3 (git 2.39.1) at 2025-08-06 10:52:41 +0000