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LoongArch: BPF: Split unconditional branch JA paths statically

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In build_insn(), both 32-bit and 64-bit unconditional branch JA paths
currently share a single case block. It relies on a runtime condition
check to multiplex between the 'off' and 'imm' fields.

Since the instruction classes are already resolved at compile-time via
distinct switch-case labels, this runtime check is redundant.

Split the two paths into individual case blocks to remove the redundant
runtime check.

Acked-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
This commit is contained in:
Tiezhu Yang 2026-08-17 22:07:39 +08:00 committed by Huacai Chen
parent 252ae40ba9
commit 9fcdba3423
1 changed files with 5 additions and 4 deletions
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9
arch/loongarch/net/bpf_jit.c
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@ -1125,11 +1125,12 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
/* PC += off */
case BPF_JMP | BPF_JA:
jmp_offset = bpf2la_offset(i, off, ctx);
if (emit_uncond_jmp(ctx, jmp_offset) < 0)
goto toofar;
break;
case BPF_JMP32 | BPF_JA:
if (BPF_CLASS(code) == BPF_JMP)
jmp_offset = bpf2la_offset(i, off, ctx);
else
jmp_offset = bpf2la_offset(i, imm, ctx);
jmp_offset = bpf2la_offset(i, imm, ctx);
if (emit_uncond_jmp(ctx, jmp_offset) < 0)
goto toofar;
break;