bpf, arm64: Support unconditional bswap

Add JIT support for unconditional bswap instructions.

Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Florent Revest <revest@chromium.org>
Acked-by: Florent Revest <revest@chromium.org>
Link: https://lore.kernel.org/bpf/20230815154158.717901-5-xukuohai@huaweicloud.com

Author: Xu Kuohai

arch/arm64/net/bpf_jit_comp.c

@@ -855,11 +855,12 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
 	/* dst = BSWAP##imm(dst) */
 	case BPF_ALU | BPF_END | BPF_FROM_LE:
 	case BPF_ALU | BPF_END | BPF_FROM_BE:
+	case BPF_ALU64 | BPF_END | BPF_FROM_LE:
 #ifdef CONFIG_CPU_BIG_ENDIAN
-		if (BPF_SRC(code) == BPF_FROM_BE)
+		if (BPF_CLASS(code) == BPF_ALU && BPF_SRC(code) == BPF_FROM_BE)
 			goto emit_bswap_uxt;
 #else /* !CONFIG_CPU_BIG_ENDIAN */
-		if (BPF_SRC(code) == BPF_FROM_LE)
+		if (BPF_CLASS(code) == BPF_ALU && BPF_SRC(code) == BPF_FROM_LE)
 			goto emit_bswap_uxt;
 #endif
 		switch (imm) {