rseq/selftests: s390: use trap4 for RSEQ_SIG

Use trap4 as the guard instruction for the restartable sequence abort
handler.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
This commit is contained in:
Martin Schwidefsky 2019-04-29 11:27:58 -04:00 committed by Shuah Khan
parent 24fa5d1efe
commit 3d4d1f05bc

View file

@ -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()