/* Restartable Sequences Linux s390 architecture header.
   Copyright (C) 2021-2026 Free Software Foundation, Inc.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#ifndef _SYS_RSEQ_H
# error "Never use <bits/rseq.h> directly; include <sys/rseq.h> instead."
#endif

/* RSEQ_SIG is a signature required before each abort handler code.

   It is a 32-bit value that maps to actual architecture code compiled
   into applications and libraries.  It needs to be defined for each
   architecture.  When choosing this value, it needs to be taken into
   account that generating invalid instructions may have ill effects on
   tools like objdump, and may also have impact on the CPU speculative
   execution efficiency in some cases.

   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
