1/* libunwind - a platform-independent unwind library 2 Copyright (C) 2010, 2011 by FERMI NATIONAL ACCELERATOR LABORATORY 3 4This file is part of libunwind. 5 6Permission is hereby granted, free of charge, to any person obtaining 7a copy of this software and associated documentation files (the 8"Software"), to deal in the Software without restriction, including 9without limitation the rights to use, copy, modify, merge, publish, 10distribute, sublicense, and/or sell copies of the Software, and to 11permit persons to whom the Software is furnished to do so, subject to 12the following conditions: 13 14The above copyright notice and this permission notice shall be 15included in all copies or substantial portions of the Software. 16 17THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 18EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 19MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 20NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE 21LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 22OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 23WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ 24 25#include "unwind_i.h" 26#include "dwarf_i.h" 27#include "offsets.h" 28 29HIDDEN void 30tdep_stash_frame (struct dwarf_cursor *d, struct dwarf_reg_state *rs) 31{ 32 struct cursor *c = (struct cursor *) dwarf_to_cursor (d); 33 unw_tdep_frame_t *f = &c->frame_info; 34 35 Debug (4, "ip=0x%lx cfa=0x%lx type %d cfa [where=%d val=%ld] cfaoff=%ld" 36 " ra=0x%lx rbp [where=%d val=%ld @0x%lx] rsp [where=%d val=%ld @0x%lx]\n", 37 d->ip, d->cfa, f->frame_type, 38 rs->reg[DWARF_CFA_REG_COLUMN].where, 39 rs->reg[DWARF_CFA_REG_COLUMN].val, 40 rs->reg[DWARF_CFA_OFF_COLUMN].val, 41 DWARF_GET_LOC(d->loc[d->ret_addr_column]), 42 rs->reg[RBP].where, rs->reg[RBP].val, DWARF_GET_LOC(d->loc[RBP]), 43 rs->reg[RSP].where, rs->reg[RSP].val, DWARF_GET_LOC(d->loc[RSP])); 44 45 /* A standard frame is defined as: 46 - CFA is register-relative offset off RBP or RSP; 47 - Return address is saved at CFA-8; 48 - RBP is unsaved or saved at CFA+offset, offset != -1; 49 - RSP is unsaved or saved at CFA+offset, offset != -1. */ 50 if (f->frame_type == UNW_X86_64_FRAME_OTHER 51 && (rs->reg[DWARF_CFA_REG_COLUMN].where == DWARF_WHERE_REG) 52 && (rs->reg[DWARF_CFA_REG_COLUMN].val == RBP 53 || rs->reg[DWARF_CFA_REG_COLUMN].val == RSP) 54 && labs((long) rs->reg[DWARF_CFA_OFF_COLUMN].val) < (1 << 29) 55 && DWARF_GET_LOC(d->loc[d->ret_addr_column]) == d->cfa-8 56 && (rs->reg[RBP].where == DWARF_WHERE_UNDEF 57 || rs->reg[RBP].where == DWARF_WHERE_SAME 58 || (rs->reg[RBP].where == DWARF_WHERE_CFAREL 59 && labs((long) rs->reg[RBP].val) < (1 << 14) 60 && rs->reg[RBP].val+1 != 0)) 61 && (rs->reg[RSP].where == DWARF_WHERE_UNDEF 62 || rs->reg[RSP].where == DWARF_WHERE_SAME 63 || (rs->reg[RSP].where == DWARF_WHERE_CFAREL 64 && labs((long) rs->reg[RSP].val) < (1 << 14) 65 && rs->reg[RSP].val+1 != 0))) 66 { 67 /* Save information for a standard frame. */ 68 f->frame_type = UNW_X86_64_FRAME_STANDARD; 69 f->cfa_reg_sp = (rs->reg[DWARF_CFA_REG_COLUMN].val == RSP); 70 f->cfa_reg_offset = rs->reg[DWARF_CFA_OFF_COLUMN].val; 71 if (rs->reg[RBP].where == DWARF_WHERE_CFAREL) 72 f->fp_cfa_offset = rs->reg[RBP].val; 73 if (rs->reg[RSP].where == DWARF_WHERE_CFAREL) 74 f->sp_cfa_offset = rs->reg[RSP].val; 75 Debug (4, " standard frame\n"); 76 } 77 78#ifdef __linux__ 79 /* Signal frame was detected via augmentation in tdep_fetch_frame() */ 80 else if (f->frame_type == UNW_X86_64_FRAME_SIGRETURN) 81 { 82 /* Later we are going to fish out {RBP,RSP,RIP} from sigcontext via 83 their ucontext_t offsets. Confirm DWARF info agrees with the 84 offsets we expect. */ 85 86#ifndef NDEBUG 87 const unw_word_t uc = c->sigcontext_addr; 88 89 assert (DWARF_GET_LOC(d->loc[RIP]) - uc == UC_MCONTEXT_GREGS_RIP); 90 assert (DWARF_GET_LOC(d->loc[RBP]) - uc == UC_MCONTEXT_GREGS_RBP); 91 assert (DWARF_GET_LOC(d->loc[RSP]) - uc == UC_MCONTEXT_GREGS_RSP); 92#endif 93 94 Debug (4, " sigreturn frame\n"); 95 } 96#endif 97 98 /* PLT and guessed RBP-walked frames are handled in unw_step(). */ 99 else 100 { 101 Debug (4, " unusual frame\n"); 102 } 103} 104 105#ifdef __linux__ 106 107HIDDEN void 108tdep_fetch_frame (struct dwarf_cursor *dw, unw_word_t ip, int need_unwind_info) 109{ 110 struct cursor *c = (struct cursor *) dw; 111 assert(! need_unwind_info || dw->pi_valid); 112 assert(! need_unwind_info || dw->pi.unwind_info); 113 if (dw->pi_valid 114 && dw->pi.unwind_info 115 && ((struct dwarf_cie_info *) dw->pi.unwind_info)->signal_frame) 116 c->sigcontext_format = X86_64_SCF_LINUX_RT_SIGFRAME; 117 else 118 c->sigcontext_format = X86_64_SCF_NONE; 119 120 Debug(5, "fetch frame ip=0x%lx cfa=0x%lx format=%d\n", 121 dw->ip, dw->cfa, c->sigcontext_format); 122} 123 124HIDDEN void 125tdep_cache_frame (struct dwarf_cursor *dw, struct dwarf_reg_state *rs) 126{ 127 struct cursor *c = (struct cursor *) dw; 128 rs->signal_frame = c->sigcontext_format; 129 130 Debug(5, "cache frame ip=0x%lx cfa=0x%lx format=%d\n", 131 dw->ip, dw->cfa, c->sigcontext_format); 132} 133 134HIDDEN void 135tdep_reuse_frame (struct dwarf_cursor *dw, struct dwarf_reg_state *rs) 136{ 137 struct cursor *c = (struct cursor *) dw; 138 c->sigcontext_format = rs->signal_frame; 139 if (c->sigcontext_format == X86_64_SCF_LINUX_RT_SIGFRAME) 140 { 141 c->frame_info.frame_type = UNW_X86_64_FRAME_SIGRETURN; 142 /* Offset from cfa to ucontext_t in signal frame. */ 143 c->frame_info.cfa_reg_offset = 0; 144 c->sigcontext_addr = dw->cfa; 145 } 146 else 147 c->sigcontext_addr = 0; 148 149 Debug(5, "reuse frame ip=0x%lx cfa=0x%lx format=%d addr=0x%lx offset=%+d\n", 150 dw->ip, dw->cfa, c->sigcontext_format, c->sigcontext_addr, 151 (c->sigcontext_format == X86_64_SCF_LINUX_RT_SIGFRAME 152 ? c->frame_info.cfa_reg_offset : 0)); 153} 154 155#endif 156