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-rw-r--r--tools/lib/bpf/bpf_gen_internal.h12
-rw-r--r--tools/lib/bpf/gen_loader.c97
-rw-r--r--tools/lib/bpf/libbpf.c13
3 files changed, 99 insertions, 23 deletions
diff --git a/tools/lib/bpf/bpf_gen_internal.h b/tools/lib/bpf/bpf_gen_internal.h
index b8d41d6fbc40..d26e5472fe50 100644
--- a/tools/lib/bpf/bpf_gen_internal.h
+++ b/tools/lib/bpf/bpf_gen_internal.h
@@ -8,13 +8,19 @@ struct ksym_relo_desc {
int kind;
int insn_idx;
bool is_weak;
+ bool is_typeless;
};
struct ksym_desc {
const char *name;
int ref;
int kind;
- int off;
+ union {
+ /* used for kfunc */
+ int off;
+ /* used for typeless ksym */
+ bool typeless;
+ };
int insn;
};
@@ -49,7 +55,7 @@ void bpf_gen__prog_load(struct bpf_gen *gen, struct bpf_prog_load_params *load_a
void bpf_gen__map_update_elem(struct bpf_gen *gen, int map_idx, void *value, __u32 value_size);
void bpf_gen__map_freeze(struct bpf_gen *gen, int map_idx);
void bpf_gen__record_attach_target(struct bpf_gen *gen, const char *name, enum bpf_attach_type type);
-void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak, int kind,
- int insn_idx);
+void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak,
+ bool is_typeless, int kind, int insn_idx);
#endif
diff --git a/tools/lib/bpf/gen_loader.c b/tools/lib/bpf/gen_loader.c
index e552484ae4a4..bae065a9dbec 100644
--- a/tools/lib/bpf/gen_loader.c
+++ b/tools/lib/bpf/gen_loader.c
@@ -560,7 +560,7 @@ static void emit_find_attach_target(struct bpf_gen *gen)
}
void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak,
- int kind, int insn_idx)
+ bool is_typeless, int kind, int insn_idx)
{
struct ksym_relo_desc *relo;
@@ -573,6 +573,7 @@ void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak,
relo += gen->relo_cnt;
relo->name = name;
relo->is_weak = is_weak;
+ relo->is_typeless = is_typeless;
relo->kind = kind;
relo->insn_idx = insn_idx;
gen->relo_cnt++;
@@ -622,6 +623,29 @@ static void emit_bpf_find_by_name_kind(struct bpf_gen *gen, struct ksym_relo_des
debug_ret(gen, "find_by_name_kind(%s,%d)", relo->name, relo->kind);
}
+/* Overwrites BPF_REG_{0, 1, 2, 3, 4, 7}
+ * Returns result in BPF_REG_7
+ * Returns u64 symbol addr in BPF_REG_9
+ */
+static void emit_bpf_kallsyms_lookup_name(struct bpf_gen *gen, struct ksym_relo_desc *relo)
+{
+ int name_off, len = strlen(relo->name) + 1, res_off;
+
+ name_off = add_data(gen, relo->name, len);
+ res_off = add_data(gen, NULL, 8); /* res is u64 */
+ emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
+ 0, 0, 0, name_off));
+ emit(gen, BPF_MOV64_IMM(BPF_REG_2, len));
+ emit(gen, BPF_MOV64_IMM(BPF_REG_3, 0));
+ emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_4, BPF_PSEUDO_MAP_IDX_VALUE,
+ 0, 0, 0, res_off));
+ emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_4));
+ emit(gen, BPF_EMIT_CALL(BPF_FUNC_kallsyms_lookup_name));
+ emit(gen, BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0));
+ emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0));
+ debug_ret(gen, "kallsyms_lookup_name(%s,%d)", relo->name, relo->kind);
+}
+
/* Expects:
* BPF_REG_8 - pointer to instruction
*
@@ -701,6 +725,58 @@ log:
relo->name, kdesc->ref);
}
+static void emit_ksym_relo_log(struct bpf_gen *gen, struct ksym_relo_desc *relo,
+ int ref)
+{
+ if (!gen->log_level)
+ return;
+ emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_8,
+ offsetof(struct bpf_insn, imm)));
+ emit(gen, BPF_LDX_MEM(BPF_H, BPF_REG_9, BPF_REG_8, sizeof(struct bpf_insn) +
+ offsetof(struct bpf_insn, imm)));
+ debug_regs(gen, BPF_REG_7, BPF_REG_9, " var t=%d w=%d (%s:count=%d): imm[0]: %%d, imm[1]: %%d",
+ relo->is_typeless, relo->is_weak, relo->name, ref);
+ emit(gen, BPF_LDX_MEM(BPF_B, BPF_REG_9, BPF_REG_8, offsetofend(struct bpf_insn, code)));
+ debug_regs(gen, BPF_REG_9, -1, " var t=%d w=%d (%s:count=%d): insn.reg",
+ relo->is_typeless, relo->is_weak, relo->name, ref);
+}
+
+/* Expects:
+ * BPF_REG_8 - pointer to instruction
+ */
+static void emit_relo_ksym_typeless(struct bpf_gen *gen,
+ struct ksym_relo_desc *relo, int insn)
+{
+ struct ksym_desc *kdesc;
+
+ kdesc = get_ksym_desc(gen, relo);
+ if (!kdesc)
+ return;
+ /* try to copy from existing ldimm64 insn */
+ if (kdesc->ref > 1) {
+ move_blob2blob(gen, insn + offsetof(struct bpf_insn, imm), 4,
+ kdesc->insn + offsetof(struct bpf_insn, imm));
+ move_blob2blob(gen, insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm), 4,
+ kdesc->insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm));
+ goto log;
+ }
+ /* remember insn offset, so we can copy ksym addr later */
+ kdesc->insn = insn;
+ /* skip typeless ksym_desc in fd closing loop in cleanup_relos */
+ kdesc->typeless = true;
+ emit_bpf_kallsyms_lookup_name(gen, relo);
+ emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_7, -ENOENT, 1));
+ emit_check_err(gen);
+ /* store lower half of addr into insn[insn_idx].imm */
+ emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_9, offsetof(struct bpf_insn, imm)));
+ /* store upper half of addr into insn[insn_idx + 1].imm */
+ emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_9, 32));
+ emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_9,
+ sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm)));
+log:
+ emit_ksym_relo_log(gen, relo, kdesc->ref);
+}
+
/* Expects:
* BPF_REG_8 - pointer to instruction
*/
@@ -730,14 +806,7 @@ static void emit_relo_ksym_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo,
emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7,
sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm)));
log:
- if (!gen->log_level)
- return;
- emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_8,
- offsetof(struct bpf_insn, imm)));
- emit(gen, BPF_LDX_MEM(BPF_H, BPF_REG_9, BPF_REG_8, sizeof(struct bpf_insn) +
- offsetof(struct bpf_insn, imm)));
- debug_regs(gen, BPF_REG_7, BPF_REG_9, " var (%s:count=%d): imm: %%d, fd: %%d",
- relo->name, kdesc->ref);
+ emit_ksym_relo_log(gen, relo, kdesc->ref);
}
static void emit_relo(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insns)
@@ -749,7 +818,10 @@ static void emit_relo(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insn
emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_8, BPF_PSEUDO_MAP_IDX_VALUE, 0, 0, 0, insn));
switch (relo->kind) {
case BTF_KIND_VAR:
- emit_relo_ksym_btf(gen, relo, insn);
+ if (relo->is_typeless)
+ emit_relo_ksym_typeless(gen, relo, insn);
+ else
+ emit_relo_ksym_btf(gen, relo, insn);
break;
case BTF_KIND_FUNC:
emit_relo_kfunc_btf(gen, relo, insn);
@@ -774,12 +846,13 @@ static void cleanup_relos(struct bpf_gen *gen, int insns)
int i, insn;
for (i = 0; i < gen->nr_ksyms; i++) {
- if (gen->ksyms[i].kind == BTF_KIND_VAR) {
+ /* only close fds for typed ksyms and kfuncs */
+ if (gen->ksyms[i].kind == BTF_KIND_VAR && !gen->ksyms[i].typeless) {
/* close fd recorded in insn[insn_idx + 1].imm */
insn = gen->ksyms[i].insn;
insn += sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm);
emit_sys_close_blob(gen, insn);
- } else { /* BTF_KIND_FUNC */
+ } else if (gen->ksyms[i].kind == BTF_KIND_FUNC) {
emit_sys_close_blob(gen, blob_fd_array_off(gen, gen->ksyms[i].off));
if (gen->ksyms[i].off < MAX_FD_ARRAY_SZ)
gen->nr_fd_array--;
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 232e4efe82e9..73e1e70a722f 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -6575,17 +6575,14 @@ static int bpf_program__record_externs(struct bpf_program *prog)
case RELO_EXTERN_VAR:
if (ext->type != EXT_KSYM)
continue;
- if (!ext->ksym.type_id) {
- pr_warn("typeless ksym %s is not supported yet\n",
- ext->name);
- return -ENOTSUP;
- }
- bpf_gen__record_extern(obj->gen_loader, ext->name, ext->is_weak,
+ bpf_gen__record_extern(obj->gen_loader, ext->name,
+ ext->is_weak, !ext->ksym.type_id,
BTF_KIND_VAR, relo->insn_idx);
break;
case RELO_EXTERN_FUNC:
- bpf_gen__record_extern(obj->gen_loader, ext->name, ext->is_weak,
- BTF_KIND_FUNC, relo->insn_idx);
+ bpf_gen__record_extern(obj->gen_loader, ext->name,
+ ext->is_weak, false, BTF_KIND_FUNC,
+ relo->insn_idx);
break;
default:
continue;
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-25 02:54:35 +0000