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-rw-r--r--tools/lib/bpf/libbpf.c145
1 files changed, 140 insertions, 5 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 882759dfc33e..77d420c02094 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -4115,6 +4115,8 @@ static const char *core_relo_kind_str(enum bpf_core_relo_kind kind)
case BPF_TYPE_ID_TARGET: return "target_type_id";
case BPF_TYPE_EXISTS: return "type_exists";
case BPF_TYPE_SIZE: return "type_size";
+ case BPF_ENUMVAL_EXISTS: return "enumval_exists";
+ case BPF_ENUMVAL_VALUE: return "enumval_value";
default: return "unknown";
}
}
@@ -4147,6 +4149,17 @@ static bool core_relo_is_type_based(enum bpf_core_relo_kind kind)
}
}
+static bool core_relo_is_enumval_based(enum bpf_core_relo_kind kind)
+{
+ switch (kind) {
+ case BPF_ENUMVAL_EXISTS:
+ case BPF_ENUMVAL_VALUE:
+ return true;
+ default:
+ return false;
+ }
+}
+
/*
* Turn bpf_core_relo into a low- and high-level spec representation,
* validating correctness along the way, as well as calculating resulting
@@ -4180,6 +4193,9 @@ static bool core_relo_is_type_based(enum bpf_core_relo_kind kind)
* Type-based relocations (TYPE_EXISTS/TYPE_SIZE,
* TYPE_ID_LOCAL/TYPE_ID_TARGET) don't capture any field information. Their
* spec and raw_spec are kept empty.
+ *
+ * Enum value-based relocations (ENUMVAL_EXISTS/ENUMVAL_VALUE) use access
+ * string to specify enumerator's value index that need to be relocated.
*/
static int bpf_core_parse_spec(const struct btf *btf,
__u32 type_id,
@@ -4224,16 +4240,25 @@ static int bpf_core_parse_spec(const struct btf *btf,
if (spec->raw_len == 0)
return -EINVAL;
- /* first spec value is always reloc type array index */
t = skip_mods_and_typedefs(btf, type_id, &id);
if (!t)
return -EINVAL;
access_idx = spec->raw_spec[0];
- spec->spec[0].type_id = id;
- spec->spec[0].idx = access_idx;
+ acc = &spec->spec[0];
+ acc->type_id = id;
+ acc->idx = access_idx;
spec->len++;
+ if (core_relo_is_enumval_based(relo_kind)) {
+ if (!btf_is_enum(t) || spec->raw_len > 1 || access_idx >= btf_vlen(t))
+ return -EINVAL;
+
+ /* record enumerator name in a first accessor */
+ acc->name = btf__name_by_offset(btf, btf_enum(t)[access_idx].name_off);
+ return 0;
+ }
+
if (!core_relo_is_field_based(relo_kind))
return -EINVAL;
@@ -4676,6 +4701,39 @@ static int bpf_core_spec_match(struct bpf_core_spec *local_spec,
local_acc = &local_spec->spec[0];
targ_acc = &targ_spec->spec[0];
+ if (core_relo_is_enumval_based(local_spec->relo_kind)) {
+ size_t local_essent_len, targ_essent_len;
+ const struct btf_enum *e;
+ const char *targ_name;
+
+ /* has to resolve to an enum */
+ targ_type = skip_mods_and_typedefs(targ_spec->btf, targ_id, &targ_id);
+ if (!btf_is_enum(targ_type))
+ return 0;
+
+ local_essent_len = bpf_core_essential_name_len(local_acc->name);
+
+ for (i = 0, e = btf_enum(targ_type); i < btf_vlen(targ_type); i++, e++) {
+ targ_name = btf__name_by_offset(targ_spec->btf, e->name_off);
+ targ_essent_len = bpf_core_essential_name_len(targ_name);
+ if (targ_essent_len != local_essent_len)
+ continue;
+ if (strncmp(local_acc->name, targ_name, local_essent_len) == 0) {
+ targ_acc->type_id = targ_id;
+ targ_acc->idx = i;
+ targ_acc->name = targ_name;
+ targ_spec->len++;
+ targ_spec->raw_spec[targ_spec->raw_len] = targ_acc->idx;
+ targ_spec->raw_len++;
+ return 1;
+ }
+ }
+ return 0;
+ }
+
+ if (!core_relo_is_field_based(local_spec->relo_kind))
+ return -EINVAL;
+
for (i = 0; i < local_spec->len; i++, local_acc++, targ_acc++) {
targ_type = skip_mods_and_typedefs(targ_spec->btf, targ_id,
&targ_id);
@@ -4880,6 +4938,31 @@ static int bpf_core_calc_type_relo(const struct bpf_core_relo *relo,
return 0;
}
+static int bpf_core_calc_enumval_relo(const struct bpf_core_relo *relo,
+ const struct bpf_core_spec *spec,
+ __u32 *val)
+{
+ const struct btf_type *t;
+ const struct btf_enum *e;
+
+ switch (relo->kind) {
+ case BPF_ENUMVAL_EXISTS:
+ *val = spec ? 1 : 0;
+ break;
+ case BPF_ENUMVAL_VALUE:
+ if (!spec)
+ return -EUCLEAN; /* request instruction poisoning */
+ t = btf__type_by_id(spec->btf, spec->spec[0].type_id);
+ e = btf_enum(t) + spec->spec[0].idx;
+ *val = e->val;
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ return 0;
+}
+
struct bpf_core_relo_res
{
/* expected value in the instruction, unless validate == false */
@@ -4918,6 +5001,9 @@ static int bpf_core_calc_relo(const struct bpf_program *prog,
} else if (core_relo_is_type_based(relo->kind)) {
err = bpf_core_calc_type_relo(relo, local_spec, &res->orig_val);
err = err ?: bpf_core_calc_type_relo(relo, targ_spec, &res->new_val);
+ } else if (core_relo_is_enumval_based(relo->kind)) {
+ err = bpf_core_calc_enumval_relo(relo, local_spec, &res->orig_val);
+ err = err ?: bpf_core_calc_enumval_relo(relo, targ_spec, &res->new_val);
}
if (err == -EUCLEAN) {
@@ -4954,6 +5040,11 @@ static void bpf_core_poison_insn(struct bpf_program *prog, int relo_idx,
insn->imm = 195896080; /* => 0xbad2310 => "bad relo" */
}
+static bool is_ldimm64(struct bpf_insn *insn)
+{
+ return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
+}
+
/*
* Patch relocatable BPF instruction.
*
@@ -4966,6 +5057,7 @@ static void bpf_core_poison_insn(struct bpf_program *prog, int relo_idx,
* 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 = <imm64> (load with 64-bit immediate value).
*/
static int bpf_core_patch_insn(struct bpf_program *prog,
const struct bpf_core_relo *relo,
@@ -4984,6 +5076,11 @@ static int bpf_core_patch_insn(struct bpf_program *prog,
class = BPF_CLASS(insn->code);
if (res->poison) {
+ /* poison second part of ldimm64 to avoid confusing error from
+ * verifier about "unknown opcode 00"
+ */
+ if (is_ldimm64(insn))
+ bpf_core_poison_insn(prog, relo_idx, insn_idx + 1, insn + 1);
bpf_core_poison_insn(prog, relo_idx, insn_idx, insn);
return 0;
}
@@ -5012,7 +5109,7 @@ static int bpf_core_patch_insn(struct bpf_program *prog,
case BPF_ST:
case BPF_STX:
if (res->validate && insn->off != orig_val) {
- pr_warn("prog '%s': relo #%d: unexpected insn #%d (LD/LDX/ST/STX) value: got %u, exp %u -> %u\n",
+ pr_warn("prog '%s': relo #%d: unexpected insn #%d (LDX/ST/STX) value: got %u, exp %u -> %u\n",
bpf_program__title(prog, false), relo_idx,
insn_idx, insn->off, orig_val, new_val);
return -EINVAL;
@@ -5029,8 +5126,36 @@ static int bpf_core_patch_insn(struct bpf_program *prog,
bpf_program__title(prog, false), relo_idx, insn_idx,
orig_val, new_val);
break;
+ case BPF_LD: {
+ __u64 imm;
+
+ if (!is_ldimm64(insn) ||
+ insn[0].src_reg != 0 || insn[0].off != 0 ||
+ insn_idx + 1 >= prog->insns_cnt ||
+ insn[1].code != 0 || insn[1].dst_reg != 0 ||
+ insn[1].src_reg != 0 || insn[1].off != 0) {
+ pr_warn("prog '%s': relo #%d: insn #%d (LDIMM64) has unexpected form\n",
+ bpf_program__title(prog, false), relo_idx, insn_idx);
+ return -EINVAL;
+ }
+
+ imm = insn[0].imm + ((__u64)insn[1].imm << 32);
+ if (res->validate && imm != orig_val) {
+ pr_warn("prog '%s': relo #%d: unexpected insn #%d (LDIMM64) value: got %llu, exp %u -> %u\n",
+ bpf_program__title(prog, false), relo_idx,
+ insn_idx, imm, orig_val, new_val);
+ return -EINVAL;
+ }
+
+ insn[0].imm = new_val;
+ insn[1].imm = 0; /* currently only 32-bit values are supported */
+ pr_debug("prog '%s': relo #%d: patched insn #%d (LDIMM64) imm64 %llu -> %u\n",
+ bpf_program__title(prog, false), relo_idx, insn_idx,
+ imm, new_val);
+ break;
+ }
default:
- pr_warn("prog '%s': relo #%d: trying to relocate unrecognized insn #%d, code:%x, src:%x, dst:%x, off:%x, imm:%x\n",
+ pr_warn("prog '%s': relo #%d: trying to relocate unrecognized insn #%d, code:0x%x, src:0x%x, dst:0x%x, off:0x%x, imm:0x%x\n",
bpf_program__title(prog, false), relo_idx,
insn_idx, insn->code, insn->src_reg, insn->dst_reg,
insn->off, insn->imm);
@@ -5047,6 +5172,7 @@ static int bpf_core_patch_insn(struct bpf_program *prog,
static void bpf_core_dump_spec(int level, const struct bpf_core_spec *spec)
{
const struct btf_type *t;
+ const struct btf_enum *e;
const char *s;
__u32 type_id;
int i;
@@ -5060,6 +5186,15 @@ static void bpf_core_dump_spec(int level, const struct bpf_core_spec *spec)
if (core_relo_is_type_based(spec->relo_kind))
return;
+ if (core_relo_is_enumval_based(spec->relo_kind)) {
+ t = skip_mods_and_typedefs(spec->btf, type_id, NULL);
+ e = btf_enum(t) + spec->raw_spec[0];
+ s = btf__name_by_offset(spec->btf, e->name_off);
+
+ libbpf_print(level, "::%s = %u", s, e->val);
+ return;
+ }
+
if (core_relo_is_field_based(spec->relo_kind)) {
for (i = 0; i < spec->len; i++) {
if (spec->spec[i].name)
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-14 00:20:45 +0000