From a1f20f42a7934e50bca1b1b64c66eb9c9bdda93a Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Sat, 21 Sep 2019 21:14:27 +0800 Subject: [PATCH] s390/bpf: fix lcgr instruction encoding [ Upstream commit bb2d267c448f4bc3a3389d97c56391cb779178ae ] "masking, test in bounds 3" fails on s390, because BPF_ALU64_IMM(BPF_NEG, BPF_REG_2, 0) ignores the top 32 bits of BPF_REG_2. The reason is that JIT emits lcgfr instead of lcgr. The associated comment indicates that the code was intended to emit lcgr in the first place, it's just that the wrong opcode was used. Fix by using the correct opcode. Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend") Signed-off-by: Ilya Leoshkevich Acked-by: Vasily Gorbik Signed-off-by: Daniel Borkmann Signed-off-by: Sasha Levin Signed-off-by: Yang Yingliang --- arch/s390/net/bpf_jit_comp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index d7052cbe984f..a3ce1fdc3d80 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -841,7 +841,7 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i break; case BPF_ALU64 | BPF_NEG: /* dst = -dst */ /* lcgr %dst,%dst */ - EMIT4(0xb9130000, dst_reg, dst_reg); + EMIT4(0xb9030000, dst_reg, dst_reg); break; /* * BPF_FROM_BE/LE -- GitLab