[PATCH for 5.2 07/12] rseq/selftests: s390: use trap4 for RSEQ_SIG
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STALE2689d
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: 2019-04-29 15:30:18
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lkml
Subsystem:
kernel selftest framework, restartable sequences support, the rest · Maintainers:
Shuah Khan, Shuah Khan, Mathieu Desnoyers, Peter Zijlstra, "Paul E. McKenney", Boqun Feng, Linus Torvalds
Revision v1 of 2 in this series.
Revisions (2)
- rfc [diff vs current]
- v1 current
From: Martin Schwidefsky <redacted> Use trap4 as the guard instruction for the restartable sequence abort handler. Signed-off-by: Martin Schwidefsky <redacted> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> --- 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()
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2.11.0