1 /* DWARF2 EH unwinding support for S/390 Linux. 2 Copyright (C) 2004-2013 Free Software Foundation, Inc. 3 4 This file is part of GCC. 5 6 GCC is free software; you can redistribute it and/or modify it under 7 the terms of the GNU General Public License as published by the Free 8 Software Foundation; either version 3, or (at your option) any later 9 version. 10 11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY 12 WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 for more details. 15 16 Under Section 7 of GPL version 3, you are granted additional 17 permissions described in the GCC Runtime Library Exception, version 18 3.1, as published by the Free Software Foundation. 19 20 You should have received a copy of the GNU General Public License and 21 a copy of the GCC Runtime Library Exception along with this program; 22 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 <http://www.gnu.org/licenses/>. */ 24 25 /* Do code reading to identify a signal frame, and set the frame 26 state data appropriately. See unwind-dw2.c for the structs. */ 27 28 #define MD_FALLBACK_FRAME_STATE_FOR s390_fallback_frame_state 29 30 static _Unwind_Reason_Code 31 s390_fallback_frame_state (struct _Unwind_Context *context, 32 _Unwind_FrameState *fs) 33 { 34 static const unsigned char dwarf_to_fpr_map[16] = 35 { 0, 2, 4, 6, 1, 3, 5, 7, 8, 10, 12, 14, 9, 11, 13, 15 }; 36 unsigned char *pc = context->ra; 37 long new_cfa; 38 int i; 39 40 typedef struct 41 { 42 unsigned long psw_mask; 43 unsigned long psw_addr; 44 unsigned long gprs[16]; 45 unsigned int acrs[16]; 46 unsigned int fpc; 47 unsigned int __pad; 48 double fprs[16]; 49 } __attribute__ ((__aligned__ (8))) sigregs_; 50 51 sigregs_ *regs; 52 int *signo; 53 54 /* svc $__NR_sigreturn or svc $__NR_rt_sigreturn */ 55 if (pc[0] != 0x0a || (pc[1] != 119 && pc[1] != 173)) 56 return _URC_END_OF_STACK; 57 58 /* Legacy frames: 59 old signal mask (8 bytes) 60 pointer to sigregs (8 bytes) - points always to next location 61 sigregs 62 retcode 63 This frame layout was used on kernels < 2.6.9 for non-RT frames, 64 and on kernels < 2.4.13 for RT frames as well. Note that we need 65 to look at RA to detect this layout -- this means that if you use 66 sa_restorer to install a different signal restorer on a legacy 67 kernel, unwinding from signal frames will not work. */ 68 if (context->ra == context->cfa + 16 + sizeof (sigregs_)) 69 { 70 regs = (sigregs_ *)(context->cfa + 16); 71 signo = NULL; 72 } 73 74 /* New-style RT frame: 75 retcode + alignment (8 bytes) 76 siginfo (128 bytes) 77 ucontext (contains sigregs) */ 78 else if (pc[1] == 173 /* __NR_rt_sigreturn */) 79 { 80 struct ucontext_ 81 { 82 unsigned long uc_flags; 83 struct ucontext_ *uc_link; 84 unsigned long uc_stack[3]; 85 sigregs_ uc_mcontext; 86 } *uc = context->cfa + 8 + 128; 87 88 regs = &uc->uc_mcontext; 89 signo = context->cfa + sizeof(long); 90 } 91 92 /* New-style non-RT frame: 93 old signal mask (8 bytes) 94 pointer to sigregs (followed by signal number) */ 95 else 96 { 97 regs = *(sigregs_ **)(context->cfa + 8); 98 signo = (int *)(regs + 1); 99 } 100 101 new_cfa = regs->gprs[15] + 16*sizeof(long) + 32; 102 fs->regs.cfa_how = CFA_REG_OFFSET; 103 fs->regs.cfa_reg = 15; 104 fs->regs.cfa_offset = 105 new_cfa - (long) context->cfa + 16*sizeof(long) + 32; 106 107 for (i = 0; i < 16; i++) 108 { 109 fs->regs.reg[i].how = REG_SAVED_OFFSET; 110 fs->regs.reg[i].loc.offset = 111 (long)®s->gprs[i] - new_cfa; 112 } 113 for (i = 0; i < 16; i++) 114 { 115 fs->regs.reg[16+i].how = REG_SAVED_OFFSET; 116 fs->regs.reg[16+i].loc.offset = 117 (long)®s->fprs[dwarf_to_fpr_map[i]] - new_cfa; 118 } 119 120 /* Load return addr from PSW into dummy register 32. */ 121 122 fs->regs.reg[32].how = REG_SAVED_OFFSET; 123 fs->regs.reg[32].loc.offset = (long)®s->psw_addr - new_cfa; 124 fs->retaddr_column = 32; 125 /* SIGILL, SIGFPE and SIGTRAP are delivered with psw_addr 126 after the faulting instruction rather than before it. 127 Don't set FS->signal_frame in that case. */ 128 if (!signo || (*signo != 4 && *signo != 5 && *signo != 8)) 129 fs->signal_frame = 1; 130 131 return _URC_NO_REASON; 132 } 133