arm32, bpf: add support for unconditional bswap instruction

The cpuv4 added a new unconditional bswap instruction with following behaviour: BPF_ALU64 | BPF_TO_LE | BPF_END with imm = 16/32/64 means: dst = bswap16(dst) dst = bswap32(dst) dst = bswap64(dst) As we already support converting to big-endian from little-endian we can use the same for unconditional bswap. just treat the unconditional scenario the same as big-endian conversion. Signed-off-by: Puranjay Mohan <[email protected]> Reviewed-by: Russell King (Oracle) <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]>
kawasaki · Sep 16, 2023 · 1cfb7ea · 1cfb7ea
1 parent fc83265
commit 1cfb7ea
Showing 1 changed file with 5 additions and 3 deletions.
diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
@@ -1635,10 +1635,12 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 		break;
 	/* dst = htole(dst) */
 	/* dst = htobe(dst) */
-	case BPF_ALU | BPF_END | BPF_FROM_LE:
-	case BPF_ALU | BPF_END | BPF_FROM_BE:
+	case BPF_ALU | BPF_END | BPF_FROM_LE: /* also BPF_TO_LE */
+	case BPF_ALU | BPF_END | BPF_FROM_BE: /* also BPF_TO_BE */
+	/* dst = bswap(dst) */
+	case BPF_ALU64 | BPF_END | BPF_FROM_LE: /* also 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)
 			goto emit_bswap_uxt;
 		switch (imm) {
 		case 16: