path: root/tools/testing/selftests
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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2019-04-29 11:27:58 -0400
committerShuah Khan <skhan@linuxfoundation.org>2019-05-07 15:32:14 -0600
commit3d4d1f05bc990f240d66b0ffaf7121397e14df19 (patch)
treecacfa4eb53e092e4418d01e15259507657b23ccb /tools/testing/selftests
parentrseq/selftests: x86: use ud1 instruction as RSEQ_SIG opcode (diff)
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>
Diffstat (limited to 'tools/testing/selftests')
1 files changed, 8 insertions, 1 deletions
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()