1/* DWARF2 EH unwinding support for Alpha Linux. 2 Copyright (C) 2004-2022 Free Software Foundation, Inc. 3 4This file is part of GCC. 5 6GCC is free software; you can redistribute it and/or modify 7it under the terms of the GNU General Public License as published by 8the Free Software Foundation; either version 3, or (at your option) 9any later version. 10 11GCC is distributed in the hope that it will be useful, 12but WITHOUT ANY WARRANTY; without even the implied warranty of 13MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14GNU General Public License for more details. 15 16Under Section 7 of GPL version 3, you are granted additional 17permissions described in the GCC Runtime Library Exception, version 183.1, as published by the Free Software Foundation. 19 20You should have received a copy of the GNU General Public License and 21a copy of the GCC Runtime Library Exception along with this program; 22see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23<http://www.gnu.org/licenses/>. */ 24 25#ifndef inhibit_libc 26/* Do code reading to identify a signal frame, and set the frame 27 state data appropriately. See unwind-dw2.c for the structs. */ 28 29#include <signal.h> 30#include <sys/ucontext.h> 31 32#define MD_FALLBACK_FRAME_STATE_FOR alpha_fallback_frame_state 33 34static _Unwind_Reason_Code 35alpha_fallback_frame_state (struct _Unwind_Context *context, 36 _Unwind_FrameState *fs) 37{ 38 unsigned int *pc = context->ra; 39 struct sigcontext *sc; 40 long new_cfa; 41 int i; 42 43 if (pc[0] != 0x47fe0410 /* mov $30,$16 */ 44 || pc[2] != 0x00000083) /* callsys */ 45 return _URC_END_OF_STACK; 46 if (context->cfa == 0) 47 return _URC_END_OF_STACK; 48 if (pc[1] == 0x201f0067) /* lda $0,NR_sigreturn */ 49 sc = context->cfa; 50 else if (pc[1] == 0x201f015f) /* lda $0,NR_rt_sigreturn */ 51 { 52 struct rt_sigframe { 53 siginfo_t info; 54 ucontext_t uc; 55 } *rt_ = context->cfa; 56 /* The void * cast is necessary to avoid an aliasing warning. 57 The aliasing warning is correct, but should not be a problem 58 because it does not alias anything. */ 59 sc = (struct sigcontext *) (void *) &rt_->uc.uc_mcontext; 60 } 61 else 62 return _URC_END_OF_STACK; 63 64 new_cfa = sc->sc_regs[30]; 65 fs->regs.cfa_how = CFA_REG_OFFSET; 66 fs->regs.cfa_reg = 30; 67 fs->regs.cfa_offset = new_cfa - (long) context->cfa; 68 for (i = 0; i < 30; ++i) 69 { 70 fs->regs.reg[i].how = REG_SAVED_OFFSET; 71 fs->regs.reg[i].loc.offset 72 = (long) &sc->sc_regs[i] - new_cfa; 73 } 74 for (i = 0; i < 31; ++i) 75 { 76 fs->regs.reg[i+32].how = REG_SAVED_OFFSET; 77 fs->regs.reg[i+32].loc.offset 78 = (long) &sc->sc_fpregs[i] - new_cfa; 79 } 80 fs->regs.reg[64].how = REG_SAVED_OFFSET; 81 fs->regs.reg[64].loc.offset = (long)&sc->sc_pc - new_cfa; 82 fs->retaddr_column = 64; 83 fs->signal_frame = 1; 84 85 return _URC_NO_REASON; 86} 87 88#define MD_FROB_UPDATE_CONTEXT alpha_frob_update_context 89 90/* Fix up for signal handlers that don't have S flag set. */ 91 92static void 93alpha_frob_update_context (struct _Unwind_Context *context, 94 _Unwind_FrameState *fs ATTRIBUTE_UNUSED) 95{ 96 unsigned int *pc = context->ra; 97 98 if (pc[0] == 0x47fe0410 /* mov $30,$16 */ 99 && pc[2] == 0x00000083 /* callsys */ 100 && (pc[1] == 0x201f0067 /* lda $0,NR_sigreturn */ 101 || pc[1] == 0x201f015f)) /* lda $0,NR_rt_sigreturn */ 102 _Unwind_SetSignalFrame (context, 1); 103} 104#endif 105