libbpf: Permit 64bit relocation value

Currently, the libbpf limits the relocation value to be 32bit
since all current relocations have such a limit. But with
BTF_KIND_ENUM64 support, the enum value could be 64bit.
So let us permit 64bit relocation value in libbpf.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220607062605.3716779-1-yhs@fb.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

tools/lib/bpf/relo_core.c

@@ -583,7 +583,7 @@ static int bpf_core_spec_match(struct bpf_core_spec *local_spec,
 static int bpf_core_calc_field_relo(const char *prog_name,
 				    const struct bpf_core_relo *relo,
 				    const struct bpf_core_spec *spec,
-				    __u32 *val, __u32 *field_sz, __u32 *type_id,
+				    __u64 *val, __u32 *field_sz, __u32 *type_id,
 				    bool *validate)
 {
 	const struct bpf_core_accessor *acc;
@@ -708,7 +708,7 @@ static int bpf_core_calc_field_relo(const char *prog_name,
 
 static int bpf_core_calc_type_relo(const struct bpf_core_relo *relo,
 				   const struct bpf_core_spec *spec,
-				   __u32 *val, bool *validate)
+				   __u64 *val, bool *validate)
 {
 	__s64 sz;
 
@@ -751,7 +751,7 @@ static int bpf_core_calc_type_relo(const struct bpf_core_relo *relo,
 
 static int bpf_core_calc_enumval_relo(const struct bpf_core_relo *relo,
 				      const struct bpf_core_spec *spec,
-				      __u32 *val)
+				      __u64 *val)
 {
 	const struct btf_type *t;
 	const struct btf_enum *e;
@@ -929,7 +929,7 @@ int bpf_core_patch_insn(const char *prog_name, struct bpf_insn *insn,
 			int insn_idx, const struct bpf_core_relo *relo,
 			int relo_idx, const struct bpf_core_relo_res *res)
 {
-	__u32 orig_val, new_val;
+	__u64 orig_val, new_val;
 	__u8 class;
 
 	class = BPF_CLASS(insn->code);
@@ -954,28 +954,30 @@ int bpf_core_patch_insn(const char *prog_name, struct bpf_insn *insn,
 		if (BPF_SRC(insn->code) != BPF_K)
 			return -EINVAL;
 		if (res->validate && insn->imm != orig_val) {
-			pr_warn("prog '%s': relo #%d: unexpected insn #%d (ALU/ALU64) value: got %u, exp %u -> %u\n",
+			pr_warn("prog '%s': relo #%d: unexpected insn #%d (ALU/ALU64) value: got %u, exp %llu -> %llu\n",
 				prog_name, relo_idx,
-				insn_idx, insn->imm, orig_val, new_val);
+				insn_idx, insn->imm, (unsigned long long)orig_val,
+				(unsigned long long)new_val);
 			return -EINVAL;
 		}
 		orig_val = insn->imm;
 		insn->imm = new_val;
-		pr_debug("prog '%s': relo #%d: patched insn #%d (ALU/ALU64) imm %u -> %u\n",
+		pr_debug("prog '%s': relo #%d: patched insn #%d (ALU/ALU64) imm %llu -> %llu\n",
 			 prog_name, relo_idx, insn_idx,
-			 orig_val, new_val);
+			 (unsigned long long)orig_val, (unsigned long long)new_val);
 		break;
 	case BPF_LDX:
 	case BPF_ST:
 	case BPF_STX:
 		if (res->validate && insn->off != orig_val) {
-			pr_warn("prog '%s': relo #%d: unexpected insn #%d (LDX/ST/STX) value: got %u, exp %u -> %u\n",
-				prog_name, relo_idx, insn_idx, insn->off, orig_val, new_val);
+			pr_warn("prog '%s': relo #%d: unexpected insn #%d (LDX/ST/STX) value: got %u, exp %llu -> %llu\n",
+				prog_name, relo_idx, insn_idx, insn->off, (unsigned long long)orig_val,
+				(unsigned long long)new_val);
 			return -EINVAL;
 		}
 		if (new_val > SHRT_MAX) {
-			pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) value too big: %u\n",
-				prog_name, relo_idx, insn_idx, new_val);
+			pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) value too big: %llu\n",
+				prog_name, relo_idx, insn_idx, (unsigned long long)new_val);
 			return -ERANGE;
 		}
 		if (res->fail_memsz_adjust) {
@@ -987,8 +989,9 @@ int bpf_core_patch_insn(const char *prog_name, struct bpf_insn *insn,
 
 		orig_val = insn->off;
 		insn->off = new_val;
-		pr_debug("prog '%s': relo #%d: patched insn #%d (LDX/ST/STX) off %u -> %u\n",
-			 prog_name, relo_idx, insn_idx, orig_val, new_val);
+		pr_debug("prog '%s': relo #%d: patched insn #%d (LDX/ST/STX) off %llu -> %llu\n",
+			 prog_name, relo_idx, insn_idx, (unsigned long long)orig_val,
+			 (unsigned long long)new_val);
 
 		if (res->new_sz != res->orig_sz) {
 			int insn_bytes_sz, insn_bpf_sz;
@@ -1026,18 +1029,18 @@ int bpf_core_patch_insn(const char *prog_name, struct bpf_insn *insn,
 
 		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",
+			pr_warn("prog '%s': relo #%d: unexpected insn #%d (LDIMM64) value: got %llu, exp %llu -> %llu\n",
 				prog_name, relo_idx,
 				insn_idx, (unsigned long long)imm,
-				orig_val, new_val);
+				(unsigned long long)orig_val, (unsigned long long)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",
+		insn[1].imm = new_val >> 32;
+		pr_debug("prog '%s': relo #%d: patched insn #%d (LDIMM64) imm64 %llu -> %llu\n",
 			 prog_name, relo_idx, insn_idx,
-			 (unsigned long long)imm, new_val);
+			 (unsigned long long)imm, (unsigned long long)new_val);
 		break;
 	}
 	default:
@@ -1261,10 +1264,12 @@ int bpf_core_calc_relo_insn(const char *prog_name,
 			 * decision and value, otherwise it's dangerous to
 			 * proceed due to ambiguity
 			 */
-			pr_warn("prog '%s': relo #%d: relocation decision ambiguity: %s %u != %s %u\n",
+			pr_warn("prog '%s': relo #%d: relocation decision ambiguity: %s %llu != %s %llu\n",
 				prog_name, relo_idx,
-				cand_res.poison ? "failure" : "success", cand_res.new_val,
-				targ_res->poison ? "failure" : "success", targ_res->new_val);
+				cand_res.poison ? "failure" : "success",
+				(unsigned long long)cand_res.new_val,
+				targ_res->poison ? "failure" : "success",
+				(unsigned long long)targ_res->new_val);
 			return -EINVAL;
 		}
 

tools/lib/bpf/relo_core.h

@@ -46,9 +46,9 @@ struct bpf_core_spec {
 
 struct bpf_core_relo_res {
 	/* expected value in the instruction, unless validate == false */
-	__u32 orig_val;
+	__u64 orig_val;
 	/* new value that needs to be patched up to */
-	__u32 new_val;
+	__u64 new_val;
 	/* relocation unsuccessful, poison instruction, but don't fail load */
 	bool poison;
 	/* some relocations can't be validated against orig_val */