From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mathieu Desnoyers Subject: [RFC PATCH for 5.2 06/10] rseq/selftests: s390: use trap4 for RSEQ_SIG Date: Wed, 24 Apr 2019 11:24:58 -0400 Message-ID: <20190424152502.14246-7-mathieu.desnoyers@efficios.com> References: <20190424152502.14246-1-mathieu.desnoyers@efficios.com> Return-path: In-Reply-To: <20190424152502.14246-1-mathieu.desnoyers@efficios.com> Sender: linux-kernel-owner@vger.kernel.org To: Peter Zijlstra , "Paul E . McKenney" , Boqun Feng Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, Thomas Gleixner , Andy Lutomirski , Dave Watson , Paul Turner , Andrew Morton , Russell King , Ingo Molnar , "H . Peter Anvin" , Andi Kleen , Chris Lameter , Ben Maurer , Steven Rostedt , Josh Triplett , Linus Torvalds , Catalin Marinas , Will Deacon , Michael Kerrisk , Joel Fernandes , Shuah Khan List-Id: linux-api@vger.kernel.org From: Martin Schwidefsky Use trap4 as the guard instruction for the restartable sequence abort handler. Signed-off-by: Martin Schwidefsky Signed-off-by: Mathieu Desnoyers --- tools/testing/selftests/rseq/rseq-s390.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/rseq/rseq-s390.h b/tools/testing/selftests/rseq/rseq-s390.h index 7c4f3a70b6c7..1d05c5187ae6 100644 --- a/tools/testing/selftests/rseq/rseq-s390.h +++ b/tools/testing/selftests/rseq/rseq-s390.h @@ -1,6 +1,13 @@ /* SPDX-License-Identifier: LGPL-2.1 OR MIT */ -#define RSEQ_SIG 0x53053053 +/* + * RSEQ_SIG uses the trap4 instruction. As Linux does not make use of the + * access-register mode nor the linkage stack this instruction will always + * cause a special-operation exception (the trap-enabled bit in the DUCT + * is and will stay 0). The instruction pattern is + * b2 ff 0f ff trap4 4095(%r0) + */ +#define RSEQ_SIG 0xB2FF0FFF #define rseq_smp_mb() __asm__ __volatile__ ("bcr 15,0" ::: "memory") #define rseq_smp_rmb() rseq_smp_mb() -- 2.11.0