On Sun, May 1, 2022 at 12:00 PM Yonghong Song <yhs@xxxxxx> wrote:
>
> 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.
>
> Signed-off-by: Yonghong Song <yhs@xxxxxx>
> ---
> tools/lib/bpf/relo_core.c | 24 ++++++++++++------------
> tools/lib/bpf/relo_core.h | 4 ++--
> 2 files changed, 14 insertions(+), 14 deletions(-)
>
[...]
> @@ -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);
> @@ -954,14 +954,14 @@ 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);
%llu is not valid formatter for __u64 on all architectures, please add
explicit (unsigned long long) cast
but also in general for non-ldimm64 instructions we need to check that
new value fits in 32 bits
[...]
> @@ -1026,7 +1026,7 @@ 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);
> @@ -1035,7 +1035,7 @@ int bpf_core_patch_insn(const char *prog_name, struct bpf_insn *insn,
>
> insn[0].imm = new_val;
> insn[1].imm = 0; /* currently only 32-bit values are supported */
as Dave mentioned, not anymore, so this should take higher 32-bit of new_val
> - pr_debug("prog '%s': relo #%d: patched insn #%d (LDIMM64) imm64 %llu -> %u\n",
> + 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);
> break;
> @@ -1261,7 +1261,7 @@ 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);
> diff --git a/tools/lib/bpf/relo_core.h b/tools/lib/bpf/relo_core.h
> index 073039d8ca4f..7df0da082f2c 100644
> --- 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 */
> --
> 2.30.2
>
