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- /* DWARF2 EH unwinding support for S/390 Linux.
- Copyright (C) 2004-2022 Free Software Foundation, Inc.
- This file is part of GCC.
- GCC is free software; you can redistribute it and/or modify it under
- the terms of the GNU General Public License as published by the Free
- Software Foundation; either version 3, or (at your option) any later
- version.
- GCC 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 General Public License
- for more details.
- Under Section 7 of GPL version 3, you are granted additional
- permissions described in the GCC Runtime Library Exception, version
- 3.1, as published by the Free Software Foundation.
- You should have received a copy of the GNU General Public License and
- a copy of the GCC Runtime Library Exception along with this program;
- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
- <http://www.gnu.org/licenses/>. */
- /* Do code reading to identify a signal frame, and set the frame
- state data appropriately. See unwind-dw2.c for the structs. */
- #define MD_FALLBACK_FRAME_STATE_FOR s390_fallback_frame_state
- static _Unwind_Reason_Code
- s390_fallback_frame_state (struct _Unwind_Context *context,
- _Unwind_FrameState *fs)
- {
- static const unsigned char dwarf_to_fpr_map[16] =
- { 0, 2, 4, 6, 1, 3, 5, 7, 8, 10, 12, 14, 9, 11, 13, 15 };
- unsigned char *pc = context->ra;
- long new_cfa;
- int i;
- typedef struct
- {
- unsigned long psw_mask;
- unsigned long psw_addr;
- unsigned long gprs[16];
- unsigned int acrs[16];
- unsigned int fpc;
- unsigned int __pad;
- double fprs[16];
- } __attribute__ ((__aligned__ (8))) sigregs_;
- sigregs_ *regs;
- int *signo;
- /* svc $__NR_sigreturn or svc $__NR_rt_sigreturn */
- if (pc[0] != 0x0a || (pc[1] != 119 && pc[1] != 173))
- return _URC_END_OF_STACK;
- /* Legacy frames:
- old signal mask (8 bytes)
- pointer to sigregs (8 bytes) - points always to next location
- sigregs
- retcode
- This frame layout was used on kernels < 2.6.9 for non-RT frames,
- and on kernels < 2.4.13 for RT frames as well. Note that we need
- to look at RA to detect this layout -- this means that if you use
- sa_restorer to install a different signal restorer on a legacy
- kernel, unwinding from signal frames will not work. */
- if (context->ra == context->cfa + 16 + sizeof (sigregs_))
- {
- regs = (sigregs_ *)(context->cfa + 16);
- signo = NULL;
- }
- /* New-style RT frame:
- retcode + alignment (8 bytes)
- siginfo (128 bytes)
- ucontext (contains sigregs) */
- else if (pc[1] == 173 /* __NR_rt_sigreturn */)
- {
- struct ucontext_
- {
- unsigned long uc_flags;
- struct ucontext_ *uc_link;
- unsigned long uc_stack[3];
- sigregs_ uc_mcontext;
- } *uc = context->cfa + 8 + 128;
- regs = &uc->uc_mcontext;
- signo = context->cfa + sizeof(long);
- }
- /* New-style non-RT frame:
- old signal mask (8 bytes)
- pointer to sigregs (followed by signal number) */
- else
- {
- regs = *(sigregs_ **)(context->cfa + 8);
- signo = (int *)(regs + 1);
- }
- new_cfa = regs->gprs[15] + 16*sizeof(long) + 32;
- fs->regs.cfa_how = CFA_REG_OFFSET;
- fs->regs.cfa_reg = 15;
- fs->regs.cfa_offset =
- new_cfa - (long) context->cfa + 16*sizeof(long) + 32;
- for (i = 0; i < 16; i++)
- {
- fs->regs.reg[i].how = REG_SAVED_OFFSET;
- fs->regs.reg[i].loc.offset =
- (long)®s->gprs[i] - new_cfa;
- }
- for (i = 0; i < 16; i++)
- {
- fs->regs.reg[16+i].how = REG_SAVED_OFFSET;
- fs->regs.reg[16+i].loc.offset =
- (long)®s->fprs[dwarf_to_fpr_map[i]] - new_cfa;
- }
- /* Load return addr from PSW into dummy register 32. */
- fs->regs.reg[32].how = REG_SAVED_OFFSET;
- fs->regs.reg[32].loc.offset = (long)®s->psw_addr - new_cfa;
- fs->retaddr_column = 32;
- /* SIGILL, SIGFPE and SIGTRAP are delivered with psw_addr
- after the faulting instruction rather than before it.
- Don't set FS->signal_frame in that case. */
- if (!signo || (*signo != 4 && *signo != 5 && *signo != 8))
- fs->signal_frame = 1;
- return _URC_NO_REASON;
- }
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