[PATCH v1 3/3] LoongArch: BPF: Split unconditional branch JA paths statically

[Tiezhu Yang]

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.

Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
---
 arch/loongarch/net/bpf_jit.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c
index 5f32b205a6ac..69bc30f88c44 100644
--- a/arch/loongarch/net/bpf_jit.c
+++ b/arch/loongarch/net/bpf_jit.c
@@ -1150,11 +1150,12 @@ 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;
-- 
2.42.0