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.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/lib/bpf/relo_core.c b/tools/lib/bpf/relo_core.c
index d8ab4c6..0dce564 100644 (file)
--- a/tools/lib/bpf/relo_core.c
+++ b/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 @@ poison:
                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 @@ poison:
 
                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 @@ poison:
 
                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;
                }
 

diff --git a/tools/lib/bpf/relo_core.h b/tools/lib/bpf/relo_core.h
index 073039d..7df0da0 100644 (file)
--- a/tools/lib/bpf/relo_core.h
+++ b/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 */