[PATCH bpf 2/2] bpf, mips: Fix BSWAP 32 and 16 on MIPS64

[Johan Almbladh]

The 16/32-bit byteswap implementations for MIPS64r1 and earlier do
not have an explicit zero extension afterwards. The input is first
sign-extended to 64 bits, and the byteswap sequence can then leave
the result sign-extended depending on the value of the low bits.

Add the missing zero-extension.

Found with test_bpf on MIPS64r1 emulated by QEMU.

Fixes: fbc802de6b10 ("mips, bpf: Add new eBPF JIT for 64-bit MIPS")
Signed-off-by: Johan Almbladh <johan.almbladh@xxxxxxxxxxxxxxxxx>
---
 arch/mips/net/bpf_jit_comp64.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/mips/net/bpf_jit_comp64.c b/arch/mips/net/bpf_jit_comp64.c
index fa7e9aa37f49..6681ccac9dd9 100644
--- a/arch/mips/net/bpf_jit_comp64.c
+++ b/arch/mips/net/bpf_jit_comp64.c
@@ -305,8 +305,7 @@ static void emit_bswap_r64(struct jit_context *ctx, u8 dst, u32 width)
 	case 16:
 		emit_sext(ctx, dst, dst);
 		emit_bswap_r(ctx, dst, width);
-		if (cpu_has_mips64r2 || cpu_has_mips64r6)
-			emit_zext(ctx, dst);
+		emit_zext(ctx, dst);
 		break;
 	}
 	clobber_reg(ctx, dst);
-- 
2.43.0