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kernel
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linux
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>
authored by
Martin Schwidefsky
and committed by
Shuah Khan
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tools/testing/selftests/rseq/rseq-s390.h
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tools/testing/selftests/rseq/rseq-s390.h
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/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
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#define RSEQ_SIG 0x53053053
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/*
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* RSEQ_SIG uses the trap4 instruction. As Linux does not make use of the
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* access-register mode nor the linkage stack this instruction will always
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* cause a special-operation exception (the trap-enabled bit in the DUCT
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* is and will stay 0). The instruction pattern is
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* b2 ff 0f ff trap4 4095(%r0)
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*/
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#define RSEQ_SIG 0xB2FF0FFF
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#define rseq_smp_mb() __asm__ __volatile__ ("bcr 15,0" ::: "memory")
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#define rseq_smp_rmb() rseq_smp_mb()