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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Ilya Leoshkevich <iii@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Sasha Levin <sashal@kernel.org>,
	netdev@vger.kernel.org, bpf@vger.kernel.org,
	linux-s390@vger.kernel.org
Subject: [PATCH AUTOSEL 5.2 10/94] s390/bpf: fix lcgr instruction encoding
Date: Wed,  4 Sep 2019 11:56:15 -0400	[thread overview]
Message-ID: <20190904155739.2816-10-sashal@kernel.org> (raw)
In-Reply-To: <20190904155739.2816-1-sashal@kernel.org>

From: Ilya Leoshkevich <iii@linux.ibm.com>

[ 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 <iii@linux.ibm.com>
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 5e7c630331590..9a711472cbdc0 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -853,7 +853,7 @@ 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
-- 
2.20.1


  reply	other threads:[~2019-09-04 16:20 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-04 15:56 [PATCH AUTOSEL 5.2 01/94] ieee802154: hwsim: Fix error handle path in hwsim_init_module Sasha Levin
2019-09-04 15:56 ` Sasha Levin [this message]
2019-09-04 15:56 ` [PATCH AUTOSEL 5.2 17/94] s390/bpf: use 32-bit index for tail calls Sasha Levin
2019-09-04 15:56 ` [PATCH AUTOSEL 5.2 19/94] selftests/bpf: fix "bind{4, 6} deny specific IP & port" on s390 Sasha Levin
2019-09-04 15:56 ` [PATCH AUTOSEL 5.2 20/94] tools: bpftool: close prog FD before exit on showing a single program Sasha Levin
2019-09-04 15:56 ` [PATCH AUTOSEL 5.2 30/94] xdp: unpin xdp umem pages in error path Sasha Levin
2019-09-04 15:56 ` [PATCH AUTOSEL 5.2 31/94] selftests/bpf: fix test_cgroup_storage on s390 Sasha Levin
2019-09-04 15:56 ` [PATCH AUTOSEL 5.2 32/94] selftests/bpf: add config fragment BPF_JIT Sasha Levin
2019-09-04 15:56 ` [PATCH AUTOSEL 5.2 33/94] selftests/bpf: install files test_xdp_vlan.sh Sasha Levin
2019-09-04 15:56 ` [PATCH AUTOSEL 5.2 40/94] flow_dissector: Fix potential use-after-free on BPF_PROG_DETACH Sasha Levin
2019-09-04 15:56 ` [PATCH AUTOSEL 5.2 41/94] bpf: fix use after free in prog symbol exposure Sasha Levin
2019-09-04 15:56 ` [PATCH AUTOSEL 5.2 42/94] bpf: allow narrow loads of some sk_reuseport_md fields with offset > 0 Sasha Levin

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