src/libs/libunwind/x86/Gos-linux.c

   1 /* libunwind - a platform-independent unwind library
   2    Copyright (C) 2002-2004 Hewlett-Packard Co
   3         Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
   4
   5 This file is part of libunwind.
   6
   7 Permission is hereby granted, free of charge, to any person obtaining
   8 a copy of this software and associated documentation files (the
   9 "Software"), to deal in the Software without restriction, including
  10 without limitation the rights to use, copy, modify, merge, publish,
  11 distribute, sublicense, and/or sell copies of the Software, and to
  12 permit persons to whom the Software is furnished to do so, subject to
  13 the following conditions:
  14
  15 The above copyright notice and this permission notice shall be
  16 included in all copies or substantial portions of the Software.
  17
  18 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  19 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  20 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  21 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  22 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  23 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  24 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
  25
  26 #include "unwind_i.h"
  27 #include "offsets.h"
  28
  29 PROTECTED int
  30 unw_is_signal_frame (unw_cursor_t *cursor)
  31 {
  32   struct cursor *c = (struct cursor *) cursor;
  33   unw_word_t w0, w1, ip;
  34   unw_addr_space_t as;
  35   unw_accessors_t *a;
  36   void *arg;
  37   int ret;
  38
  39   as = c->dwarf.as;
  40   a = unw_get_accessors (as);
  41   arg = c->dwarf.as_arg;
  42
  43   /* Check if EIP points at sigreturn() sequence.  On Linux, this is:
  44
  45     __restore:
  46         0x58                            pop %eax
  47         0xb8 0x77 0x00 0x00 0x00        movl 0x77,%eax
  48         0xcd 0x80                       int 0x80
  49
  50      without SA_SIGINFO, and
  51
  52     __restore_rt:
  53        0xb8 0xad 0x00 0x00 0x00        movl 0xad,%eax
  54        0xcd 0x80                       int 0x80
  55        0x00
  56
  57      if SA_SIGINFO is specified.
  58   */
  59   ip = c->dwarf.ip;
  60   if ((*a->access_mem) (as, ip, &w0, 0, arg) < 0
  61       || (*a->access_mem) (as, ip + 4, &w1, 0, arg) < 0)
  62     ret = 0;
  63   else
  64     ret = ((w0 == 0x0077b858 && w1 == 0x80cd0000)
  65          || (w0 == 0x0000adb8 && (w1 & 0xffffff) == 0x80cd00));
  66   Debug (16, "returning %d\n", ret);
  67   return ret;
  68 }
  69
  70 PROTECTED int
  71 unw_handle_signal_frame (unw_cursor_t *cursor)
  72 {
  73   struct cursor *c = (struct cursor *) cursor;
  74   int ret;
  75
  76   /* c->esp points at the arguments to the handler.  Without
  77      SA_SIGINFO, the arguments consist of a signal number
  78      followed by a struct sigcontext.  With SA_SIGINFO, the
  79      arguments consist a signal number, a siginfo *, and a
  80      ucontext *. */
  81   unw_word_t sc_addr;
  82   unw_word_t siginfo_ptr_addr = c->dwarf.cfa + 4;
  83   unw_word_t sigcontext_ptr_addr = c->dwarf.cfa + 8;
  84   unw_word_t siginfo_ptr, sigcontext_ptr;
  85   struct dwarf_loc esp_loc, siginfo_ptr_loc, sigcontext_ptr_loc;
  86
  87   siginfo_ptr_loc = DWARF_LOC (siginfo_ptr_addr, 0);
  88   sigcontext_ptr_loc = DWARF_LOC (sigcontext_ptr_addr, 0);
  89   ret = (dwarf_get (&c->dwarf, siginfo_ptr_loc, &siginfo_ptr)
  90          | dwarf_get (&c->dwarf, sigcontext_ptr_loc, &sigcontext_ptr));
  91   if (ret < 0)
  92     {
  93       Debug (2, "returning 0\n");
  94       return 0;
  95     }
  96   if (siginfo_ptr < c->dwarf.cfa
  97       || siginfo_ptr > c->dwarf.cfa + 256
  98       || sigcontext_ptr < c->dwarf.cfa
  99       || sigcontext_ptr > c->dwarf.cfa + 256)
 100     {
 101       /* Not plausible for SA_SIGINFO signal */
 102       c->sigcontext_format = X86_SCF_LINUX_SIGFRAME;
 103       c->sigcontext_addr = sc_addr = c->dwarf.cfa + 4;
 104     }
 105   else
 106     {
 107       /* If SA_SIGINFO were not specified, we actually read
 108          various segment pointers instead.  We believe that at
 109          least fs and _fsh are always zero for linux, so it is
 110          not just unlikely, but impossible that we would end
 111          up here. */
 112       c->sigcontext_format = X86_SCF_LINUX_RT_SIGFRAME;
 113       c->sigcontext_addr = sigcontext_ptr;
 114       sc_addr = sigcontext_ptr + LINUX_UC_MCONTEXT_OFF;
 115     }
 116   esp_loc = DWARF_LOC (sc_addr + LINUX_SC_ESP_OFF, 0);
 117   ret = dwarf_get (&c->dwarf, esp_loc, &c->dwarf.cfa);
 118   if (ret < 0)
 119     {
 120       Debug (2, "returning 0\n");
 121       return 0;
 122     }
 123
 124   c->dwarf.loc[EAX] = DWARF_LOC (sc_addr + LINUX_SC_EAX_OFF, 0);
 125   c->dwarf.loc[ECX] = DWARF_LOC (sc_addr + LINUX_SC_ECX_OFF, 0);
 126   c->dwarf.loc[EDX] = DWARF_LOC (sc_addr + LINUX_SC_EDX_OFF, 0);
 127   c->dwarf.loc[EBX] = DWARF_LOC (sc_addr + LINUX_SC_EBX_OFF, 0);
 128   c->dwarf.loc[EBP] = DWARF_LOC (sc_addr + LINUX_SC_EBP_OFF, 0);
 129   c->dwarf.loc[ESI] = DWARF_LOC (sc_addr + LINUX_SC_ESI_OFF, 0);
 130   c->dwarf.loc[EDI] = DWARF_LOC (sc_addr + LINUX_SC_EDI_OFF, 0);
 131   c->dwarf.loc[EFLAGS] = DWARF_NULL_LOC;
 132   c->dwarf.loc[TRAPNO] = DWARF_NULL_LOC;
 133   c->dwarf.loc[ST0] = DWARF_NULL_LOC;
 134   c->dwarf.loc[EIP] = DWARF_LOC (sc_addr + LINUX_SC_EIP_OFF, 0);
 135   c->dwarf.loc[ESP] = DWARF_LOC (sc_addr + LINUX_SC_ESP_OFF, 0);
 136
 137   return 0;
 138 }
 139
 140 HIDDEN dwarf_loc_t
 141 x86_get_scratch_loc (struct cursor *c, unw_regnum_t reg)
 142 {
 143   unw_word_t addr = c->sigcontext_addr, fpstate_addr, off;
 144   int ret, is_fpstate = 0;
 145
 146   switch (c->sigcontext_format)
 147     {
 148     case X86_SCF_NONE:
 149       return DWARF_REG_LOC (&c->dwarf, reg);
 150
 151     case X86_SCF_LINUX_SIGFRAME:
 152       break;
 153
 154     case X86_SCF_LINUX_RT_SIGFRAME:
 155       addr += LINUX_UC_MCONTEXT_OFF;
 156       break;
 157
 158     default:
 159       return DWARF_NULL_LOC;
 160     }
 161
 162   switch (reg)
 163     {
 164     case UNW_X86_GS: off = LINUX_SC_GS_OFF; break;
 165     case UNW_X86_FS: off = LINUX_SC_FS_OFF; break;
 166     case UNW_X86_ES: off = LINUX_SC_ES_OFF; break;
 167     case UNW_X86_DS: off = LINUX_SC_DS_OFF; break;
 168     case UNW_X86_EDI: off = LINUX_SC_EDI_OFF; break;
 169     case UNW_X86_ESI: off = LINUX_SC_ESI_OFF; break;
 170     case UNW_X86_EBP: off = LINUX_SC_EBP_OFF; break;
 171     case UNW_X86_ESP: off = LINUX_SC_ESP_OFF; break;
 172     case UNW_X86_EBX: off = LINUX_SC_EBX_OFF; break;
 173     case UNW_X86_EDX: off = LINUX_SC_EDX_OFF; break;
 174     case UNW_X86_ECX: off = LINUX_SC_ECX_OFF; break;
 175     case UNW_X86_EAX: off = LINUX_SC_EAX_OFF; break;
 176     case UNW_X86_TRAPNO: off = LINUX_SC_TRAPNO_OFF; break;
 177     case UNW_X86_EIP: off = LINUX_SC_EIP_OFF; break;
 178     case UNW_X86_CS: off = LINUX_SC_CS_OFF; break;
 179     case UNW_X86_EFLAGS: off = LINUX_SC_EFLAGS_OFF; break;
 180     case UNW_X86_SS: off = LINUX_SC_SS_OFF; break;
 181
 182       /* The following is probably not correct for all possible cases.
 183          Somebody who understands this better should review this for
 184          correctness.  */
 185
 186     case UNW_X86_FCW: is_fpstate = 1; off = LINUX_FPSTATE_CW_OFF; break;
 187     case UNW_X86_FSW: is_fpstate = 1; off = LINUX_FPSTATE_SW_OFF; break;
 188     case UNW_X86_FTW: is_fpstate = 1; off = LINUX_FPSTATE_TAG_OFF; break;
 189     case UNW_X86_FCS: is_fpstate = 1; off = LINUX_FPSTATE_CSSEL_OFF; break;
 190     case UNW_X86_FIP: is_fpstate = 1; off = LINUX_FPSTATE_IPOFF_OFF; break;
 191     case UNW_X86_FEA: is_fpstate = 1; off = LINUX_FPSTATE_DATAOFF_OFF; break;
 192     case UNW_X86_FDS: is_fpstate = 1; off = LINUX_FPSTATE_DATASEL_OFF; break;
 193     case UNW_X86_MXCSR: is_fpstate = 1; off = LINUX_FPSTATE_MXCSR_OFF; break;
 194
 195       /* stacked fp registers */
 196     case UNW_X86_ST0: case UNW_X86_ST1: case UNW_X86_ST2: case UNW_X86_ST3:
 197     case UNW_X86_ST4: case UNW_X86_ST5: case UNW_X86_ST6: case UNW_X86_ST7:
 198       is_fpstate = 1;
 199       off = LINUX_FPSTATE_ST0_OFF + 10*(reg - UNW_X86_ST0);
 200       break;
 201
 202      /* SSE fp registers */
 203     case UNW_X86_XMM0_lo: case UNW_X86_XMM0_hi:
 204     case UNW_X86_XMM1_lo: case UNW_X86_XMM1_hi:
 205     case UNW_X86_XMM2_lo: case UNW_X86_XMM2_hi:
 206     case UNW_X86_XMM3_lo: case UNW_X86_XMM3_hi:
 207     case UNW_X86_XMM4_lo: case UNW_X86_XMM4_hi:
 208     case UNW_X86_XMM5_lo: case UNW_X86_XMM5_hi:
 209     case UNW_X86_XMM6_lo: case UNW_X86_XMM6_hi:
 210     case UNW_X86_XMM7_lo: case UNW_X86_XMM7_hi:
 211       is_fpstate = 1;
 212       off = LINUX_FPSTATE_XMM0_OFF + 8*(reg - UNW_X86_XMM0_lo);
 213       break;
 214     case UNW_X86_XMM0:
 215     case UNW_X86_XMM1:
 216     case UNW_X86_XMM2:
 217     case UNW_X86_XMM3:
 218     case UNW_X86_XMM4:
 219     case UNW_X86_XMM5:
 220     case UNW_X86_XMM6:
 221     case UNW_X86_XMM7:
 222       is_fpstate = 1;
 223       off = LINUX_FPSTATE_XMM0_OFF + 16*(reg - UNW_X86_XMM0);
 224       break;
 225
 226     case UNW_X86_FOP:
 227     case UNW_X86_TSS:
 228     case UNW_X86_LDT:
 229     default:
 230       return DWARF_REG_LOC (&c->dwarf, reg);
 231     }
 232
 233   if (is_fpstate)
 234     {
 235       if ((ret = dwarf_get (&c->dwarf,
 236                             DWARF_MEM_LOC (&c->dwarf,
 237                                            addr + LINUX_SC_FPSTATE_OFF),
 238                             &fpstate_addr)) < 0)
 239         return DWARF_NULL_LOC;
 240
 241       if (!fpstate_addr)
 242         return DWARF_NULL_LOC;
 243
 244       return DWARF_MEM_LOC (c, fpstate_addr + off);
 245     }
 246   else
 247     return DWARF_MEM_LOC (c, addr + off);
 248 }
 249
 250 #ifndef UNW_REMOTE_ONLY
 251 HIDDEN void *
 252 x86_r_uc_addr (ucontext_t *uc, int reg)
 253 {
 254   void *addr;
 255
 256   switch (reg)
 257     {
 258     case UNW_X86_GS:  addr = &uc->uc_mcontext.gregs[REG_GS]; break;
 259     case UNW_X86_FS:  addr = &uc->uc_mcontext.gregs[REG_FS]; break;
 260     case UNW_X86_ES:  addr = &uc->uc_mcontext.gregs[REG_ES]; break;
 261     case UNW_X86_DS:  addr = &uc->uc_mcontext.gregs[REG_DS]; break;
 262     case UNW_X86_EAX: addr = &uc->uc_mcontext.gregs[REG_EAX]; break;
 263     case UNW_X86_EBX: addr = &uc->uc_mcontext.gregs[REG_EBX]; break;
 264     case UNW_X86_ECX: addr = &uc->uc_mcontext.gregs[REG_ECX]; break;
 265     case UNW_X86_EDX: addr = &uc->uc_mcontext.gregs[REG_EDX]; break;
 266     case UNW_X86_ESI: addr = &uc->uc_mcontext.gregs[REG_ESI]; break;
 267     case UNW_X86_EDI: addr = &uc->uc_mcontext.gregs[REG_EDI]; break;
 268     case UNW_X86_EBP: addr = &uc->uc_mcontext.gregs[REG_EBP]; break;
 269     case UNW_X86_EIP: addr = &uc->uc_mcontext.gregs[REG_EIP]; break;
 270     case UNW_X86_ESP: addr = &uc->uc_mcontext.gregs[REG_ESP]; break;
 271     case UNW_X86_TRAPNO:  addr = &uc->uc_mcontext.gregs[REG_TRAPNO]; break;
 272     case UNW_X86_CS:  addr = &uc->uc_mcontext.gregs[REG_CS]; break;
 273     case UNW_X86_EFLAGS:  addr = &uc->uc_mcontext.gregs[REG_EFL]; break;
 274     case UNW_X86_SS:  addr = &uc->uc_mcontext.gregs[REG_SS]; break;
 275
 276     default:
 277       addr = NULL;
 278     }
 279   return addr;
 280 }
 281
 282 HIDDEN int
 283 x86_local_resume (unw_addr_space_t as, unw_cursor_t *cursor, void *arg)
 284 {
 285   struct cursor *c = (struct cursor *) cursor;
 286   ucontext_t *uc = c->uc;
 287
 288   /* Ensure c->pi is up-to-date.  On x86, it's relatively common to be
 289      missing DWARF unwind info.  We don't want to fail in that case,
 290      because the frame-chain still would let us do a backtrace at
 291      least.  */
 292   dwarf_make_proc_info (&c->dwarf);
 293
 294   if (unlikely (c->sigcontext_format != X86_SCF_NONE))
 295     {
 296       struct sigcontext *sc = (struct sigcontext *) c->sigcontext_addr;
 297
 298       Debug (8, "resuming at ip=%x via sigreturn(%p)\n", c->dwarf.ip, sc);
 299       sigreturn (sc);
 300     }
 301   else
 302     {
 303       Debug (8, "resuming at ip=%x via setcontext()\n", c->dwarf.ip);
 304       setcontext (uc);
 305     }
 306   return -UNW_EINVAL;
 307 }
 308 #endif