On Thu, Sep 07 2023, Russell King (Oracle) wrote: > On Wed, Sep 06, 2023 at 06:33:16PM +0000, Puranjay Mohan wrote: >> @@ -1633,8 +1633,10 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) >> /* dst = htobe(dst) */ >> case BPF_ALU | BPF_END | BPF_FROM_LE: >> case BPF_ALU | BPF_END | BPF_FROM_BE: >> + /* dst = bswap(dst) */ >> + case BPF_ALU64 | BPF_END | BPF_TO_LE: >> rd = arm_bpf_get_reg64(dst, tmp, ctx); >> - if (BPF_SRC(code) == BPF_FROM_LE) >> + if (BPF_SRC(code) == BPF_FROM_LE && BPF_CLASS(code) != BPF_ALU64) > > With the addition of the BPF_ALU64 case, I'm wondering why this if() is > affected. If you were adding: > > case BPF_ALU64 | BPF_END | BPF_FROM_LE: > > then maybe there would be a reason, but the BPF_ALU64 | BPF_END | > BPF_TO_LE case will never match even the original if() statement. The reason is that these mean the same thing. from: include/uapi/linux/bpf.h #define BPF_TO_LE 0x00 /* convert to little-endian */ #define BPF_TO_BE 0x08 /* convert to big-endian */ #define BPF_FROM_LE BPF_TO_LE #define BPF_FROM_BE BPF_TO_BE So, to not cause confusion and follow the earlier cases I can add: case BPF_ALU64 | BPF_END | BPF_FROM_LE: in the next version. Thanks, Puranjay
