1/* libunwind - a platform-independent unwind library 2 Copyright (C) 2015 Imagination Technologies Limited 3 Copyright (C) 2008 CodeSourcery 4 5This file is part of libunwind. 6 7Permission is hereby granted, free of charge, to any person obtaining 8a copy of this software and associated documentation files (the 9"Software"), to deal in the Software without restriction, including 10without limitation the rights to use, copy, modify, merge, publish, 11distribute, sublicense, and/or sell copies of the Software, and to 12permit persons to whom the Software is furnished to do so, subject to 13the following conditions: 14 15The above copyright notice and this permission notice shall be 16included in all copies or substantial portions of the Software. 17 18THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 19EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 20MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 21NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE 22LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 23OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 24WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ 25 26#include "unwind_i.h" 27#include "offsets.h" 28 29static int 30mips_handle_signal_frame (unw_cursor_t *cursor) 31{ 32 struct cursor *c = (struct cursor *) cursor; 33 unw_word_t sc_addr, sp_addr = c->dwarf.cfa; 34 unw_word_t ra, fp; 35 int ret; 36 37 switch (unw_is_signal_frame (cursor)) { 38 case 1: 39 sc_addr = sp_addr + LINUX_SF_TRAMP_SIZE + sizeof (siginfo_t) + 40 LINUX_UC_MCONTEXT_OFF; 41 break; 42 case 2: 43 sc_addr = sp_addr + LINUX_UC_MCONTEXT_OFF; 44 break; 45 default: 46 return -UNW_EUNSPEC; 47 } 48 49 if (tdep_big_endian(c->dwarf.as)) 50 sc_addr += 4; 51 52 c->sigcontext_addr = sc_addr; 53 54 /* Update the dwarf cursor. */ 55 c->dwarf.loc[UNW_MIPS_R0] = DWARF_LOC (sc_addr + LINUX_SC_R0_OFF, 0); 56 c->dwarf.loc[UNW_MIPS_R1] = DWARF_LOC (sc_addr + LINUX_SC_R1_OFF, 0); 57 c->dwarf.loc[UNW_MIPS_R2] = DWARF_LOC (sc_addr + LINUX_SC_R2_OFF, 0); 58 c->dwarf.loc[UNW_MIPS_R3] = DWARF_LOC (sc_addr + LINUX_SC_R3_OFF, 0); 59 c->dwarf.loc[UNW_MIPS_R4] = DWARF_LOC (sc_addr + LINUX_SC_R4_OFF, 0); 60 c->dwarf.loc[UNW_MIPS_R5] = DWARF_LOC (sc_addr + LINUX_SC_R5_OFF, 0); 61 c->dwarf.loc[UNW_MIPS_R6] = DWARF_LOC (sc_addr + LINUX_SC_R6_OFF, 0); 62 c->dwarf.loc[UNW_MIPS_R7] = DWARF_LOC (sc_addr + LINUX_SC_R7_OFF, 0); 63 c->dwarf.loc[UNW_MIPS_R8] = DWARF_LOC (sc_addr + LINUX_SC_R8_OFF, 0); 64 c->dwarf.loc[UNW_MIPS_R9] = DWARF_LOC (sc_addr + LINUX_SC_R9_OFF, 0); 65 c->dwarf.loc[UNW_MIPS_R10] = DWARF_LOC (sc_addr + LINUX_SC_R10_OFF, 0); 66 c->dwarf.loc[UNW_MIPS_R11] = DWARF_LOC (sc_addr + LINUX_SC_R11_OFF, 0); 67 c->dwarf.loc[UNW_MIPS_R12] = DWARF_LOC (sc_addr + LINUX_SC_R12_OFF, 0); 68 c->dwarf.loc[UNW_MIPS_R13] = DWARF_LOC (sc_addr + LINUX_SC_R13_OFF, 0); 69 c->dwarf.loc[UNW_MIPS_R14] = DWARF_LOC (sc_addr + LINUX_SC_R14_OFF, 0); 70 c->dwarf.loc[UNW_MIPS_R15] = DWARF_LOC (sc_addr + LINUX_SC_R15_OFF, 0); 71 c->dwarf.loc[UNW_MIPS_R16] = DWARF_LOC (sc_addr + LINUX_SC_R16_OFF, 0); 72 c->dwarf.loc[UNW_MIPS_R17] = DWARF_LOC (sc_addr + LINUX_SC_R17_OFF, 0); 73 c->dwarf.loc[UNW_MIPS_R18] = DWARF_LOC (sc_addr + LINUX_SC_R18_OFF, 0); 74 c->dwarf.loc[UNW_MIPS_R19] = DWARF_LOC (sc_addr + LINUX_SC_R19_OFF, 0); 75 c->dwarf.loc[UNW_MIPS_R20] = DWARF_LOC (sc_addr + LINUX_SC_R20_OFF, 0); 76 c->dwarf.loc[UNW_MIPS_R21] = DWARF_LOC (sc_addr + LINUX_SC_R21_OFF, 0); 77 c->dwarf.loc[UNW_MIPS_R22] = DWARF_LOC (sc_addr + LINUX_SC_R22_OFF, 0); 78 c->dwarf.loc[UNW_MIPS_R23] = DWARF_LOC (sc_addr + LINUX_SC_R23_OFF, 0); 79 c->dwarf.loc[UNW_MIPS_R24] = DWARF_LOC (sc_addr + LINUX_SC_R24_OFF, 0); 80 c->dwarf.loc[UNW_MIPS_R25] = DWARF_LOC (sc_addr + LINUX_SC_R25_OFF, 0); 81 c->dwarf.loc[UNW_MIPS_R26] = DWARF_LOC (sc_addr + LINUX_SC_R26_OFF, 0); 82 c->dwarf.loc[UNW_MIPS_R27] = DWARF_LOC (sc_addr + LINUX_SC_R27_OFF, 0); 83 c->dwarf.loc[UNW_MIPS_R28] = DWARF_LOC (sc_addr + LINUX_SC_R28_OFF, 0); 84 c->dwarf.loc[UNW_MIPS_R29] = DWARF_LOC (sc_addr + LINUX_SC_R29_OFF, 0); 85 c->dwarf.loc[UNW_MIPS_R30] = DWARF_LOC (sc_addr + LINUX_SC_R30_OFF, 0); 86 c->dwarf.loc[UNW_MIPS_R31] = DWARF_LOC (sc_addr + LINUX_SC_R31_OFF, 0); 87 c->dwarf.loc[UNW_MIPS_PC] = DWARF_LOC (sc_addr + LINUX_SC_PC_OFF, 0); 88 89 /* Set SP/CFA and PC/IP. */ 90 dwarf_get (&c->dwarf, c->dwarf.loc[UNW_MIPS_R29], &c->dwarf.cfa); 91 92 if ((ret = dwarf_get(&c->dwarf, DWARF_LOC(sc_addr + LINUX_SC_PC_OFF, 0), 93 &c->dwarf.ip)) < 0) 94 return ret; 95 96 if ((ret = dwarf_get(&c->dwarf, DWARF_LOC(sc_addr + LINUX_SC_R31_OFF, 0), 97 &ra)) < 0) 98 return ret; 99 if ((ret = dwarf_get(&c->dwarf, DWARF_LOC(sc_addr + LINUX_SC_R30_OFF, 0), 100 &fp)) < 0) 101 return ret; 102 103 Debug (2, "SH (ip=0x%016llx, ra=0x%016llx, sp=0x%016llx, fp=0x%016llx)\n", 104 (unsigned long long)c->dwarf.ip, (unsigned long long)ra, 105 (unsigned long long)c->dwarf.cfa, (unsigned long long)fp); 106 107 c->dwarf.pi_valid = 0; 108 c->dwarf.use_prev_instr = 0; 109 110 return 1; 111} 112 113 114 115static inline 116int is_valid_fp_val(unw_word_t cfa_val, unw_word_t fp_val) 117{ 118 return fp_val > 0 && cfa_val > 0 && fp_val >cfa_val && (fp_val - cfa_val < 0x4000); 119} 120 121static int _step_n64(struct cursor *c) 122{ 123 #define FP_REG UNW_MIPS_R30 124 #define SP_REG UNW_MIPS_R29 125 #define RA_REG UNW_MIPS_R31 126 127 //TODO:handle plt entry 128 int ret; 129 unw_word_t current_fp_val = 0; 130 unw_word_t current_ra_val = 0; 131 unw_word_t current_sp_val = 0; 132 struct dwarf_loc up_fp_loc = DWARF_NULL_LOC; 133 struct dwarf_loc up_ra_loc = DWARF_NULL_LOC; 134 135 ret = dwarf_get (&c->dwarf, c->dwarf.loc[SP_REG], ¤t_sp_val); 136 if (ret < 0) 137 { 138 Debug (2, "returning %d [SP=0x%lx]\n", ret, 139 DWARF_GET_LOC (c->dwarf.loc[FP_REG])); 140 return ret; 141 } 142 ret = dwarf_get (&c->dwarf, c->dwarf.loc[FP_REG], ¤t_fp_val); 143 if (ret < 0) 144 { 145 Debug (2, "returning %d [FP=0x%lx]\n", ret, 146 DWARF_GET_LOC (c->dwarf.loc[FP_REG])); 147 return ret; 148 } 149 ret = dwarf_get (&c->dwarf, c->dwarf.loc[RA_REG], ¤t_ra_val); 150 if (ret < 0) 151 { 152 Debug (2, "returning %d [RA=0x%lx]\n", ret, 153 DWARF_GET_LOC (c->dwarf.loc[RA_REG])); 154 return ret; 155 } 156 157 Debug(2, "BEGIN GUESSING WITH SP:%p FP:%p CFA:%p at %p, RA:%p\n", 158 current_sp_val, current_fp_val, c->dwarf.cfa, 159 c->dwarf.ip, current_ra_val 160 ); 161 162 if (current_fp_val == current_sp_val) { 163 // Don't adjust FP 164 up_fp_loc = c->dwarf.loc[FP_REG]; 165 up_ra_loc = c->dwarf.loc[RA_REG]; 166 } else if (is_valid_fp_val(c->dwarf.cfa, current_fp_val)) { 167 /* Heuristic to determine incorrect guess. For FP to be a 168 valid frame it needs to be above current CFA, but don't 169 let it go more than a little. Note that we can't deduce 170 anything about new FP (fp1) since it may not be a frame 171 pointer in the frame above. Just check we get the value. */ 172 up_fp_loc = DWARF_MEM_LOC (c, current_fp_val+16); 173 up_ra_loc = DWARF_MEM_LOC (c, current_fp_val+24); 174 unw_word_t up_fp_val = 0; 175 ret = dwarf_get (&c->dwarf, up_fp_loc, &up_fp_val); 176 if (ret > 0 && is_valid_fp_val(current_fp_val, up_fp_val)) { 177 c->dwarf.loc[FP_REG] = up_fp_loc; 178 } 179 } 180 181 if (DWARF_IS_NULL_LOC (up_fp_loc)) 182 { 183 ret = 0; 184 Debug (2, "NULL %%fp loc, returning %d\n", ret); 185 return ret; 186 } 187 188 c->dwarf.loc[UNW_MIPS_PC] = c->dwarf.loc[RA_REG]; 189 c->dwarf.loc[RA_REG] = up_ra_loc; 190 c->dwarf.loc[SP_REG] = up_fp_loc; 191 c->dwarf.loc[FP_REG] = up_fp_loc; 192 c->dwarf.use_prev_instr = 1; 193 194 if (c->dwarf.ip == current_ra_val && current_fp_val == current_sp_val) { 195 // Backtrace stopped: frame did not save the PC 196 c->dwarf.ip = 0; 197 } else { 198 c->dwarf.ip = current_ra_val; 199 } 200 return (c->dwarf.ip == 0) ? 0 : 1; 201} 202 203int 204unw_step (unw_cursor_t *cursor) 205{ 206 struct cursor *c = (struct cursor *) cursor; 207 int ret; 208 209 ret = mips_handle_signal_frame (cursor); 210 if (ret < 0) 211 /* Not a signal frame, try DWARF-based unwinding. */ 212 ret = dwarf_step (&c->dwarf); 213 214 if (unlikely (ret == -UNW_ESTOPUNWIND)) 215 return ret; 216 217 if (unlikely (ret < 0)) 218 { 219#if _MIPS_SIM == _ABI64 220 return _step_n64(c); 221#else 222 return ret; 223#endif 224 } 225 226 return (c->dwarf.ip == 0) ? 0 : 1; 227} 228