libgcc/config/i386/dragonfly-unwind.h

   1 /* DWARF2 EH unwinding support for DragonFly BSD: AMD x86-64 and x86.
   2    Copyright (C) 2014-2024 Free Software Foundation, Inc.
   3    Contributed by John Marino <gnugcc@marino.st>
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 Under Section 7 of GPL version 3, you are granted additional
  18 permissions described in the GCC Runtime Library Exception, version
  19 3.1, as published by the Free Software Foundation.
  20
  21 You should have received a copy of the GNU General Public License and
  22 a copy of the GCC Runtime Library Exception along with this program;
  23 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 <http://www.gnu.org/licenses/>.  */
  25
  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 <sys/types.h>
  30 #include <sys/sysctl.h>
  31 #include <sys/param.h>
  32 #include <signal.h>
  33 #include <sys/ucontext.h>
  34 #include <machine/sigframe.h>
  35 #if __DragonFly_version > 400800
  36 #include <sys/kinfo.h>
  37 #endif
  38
  39
  40 #define REG_NAME(reg)   sf_uc.uc_mcontext.mc_## reg
  41
  42 #ifdef __x86_64__
  43 #define MD_FALLBACK_FRAME_STATE_FOR x86_64_dragonfly_fallback_frame_state
  44
  45
  46 static int
  47 x86_64_outside_sigtramp_range (unsigned char *pc)
  48 {
  49   static int sigtramp_range_determined = 0;
  50   static unsigned char *sigtramp_start, *sigtramp_end;
  51
  52   if (sigtramp_range_determined == 0)
  53     {
  54 #if __DragonFly_version > 400800
  55       struct kinfo_sigtramp kst = {0};
  56       size_t len = sizeof (kst);
  57       int mib[3] = { CTL_KERN, KERN_PROC, KERN_PROC_SIGTRAMP };
  58
  59       sigtramp_range_determined = 1;
  60       if (sysctl (mib, 3, &kst, &len, NULL, 0) == 0)
  61       {
  62         sigtramp_range_determined = 2;
  63         sigtramp_start = kst.ksigtramp_start;
  64         sigtramp_end   = kst.ksigtramp_end;
  65       }
  66 #else
  67       unsigned long ps_strings;
  68       size_t len = sizeof (ps_strings);
  69       int mib[2] = { CTL_KERN, KERN_PS_STRINGS };
  70
  71       sigtramp_range_determined = 1;
  72       if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0)
  73       {
  74         sigtramp_range_determined = 2;
  75         sigtramp_start = (unsigned char *)ps_strings - 32;
  76         sigtramp_end   = (unsigned char *)ps_strings;
  77       }
  78 #endif
  79     }
  80   if (sigtramp_range_determined < 2)  /* sysctl failed if < 2 */
  81     return 1;
  82
  83   return (pc < sigtramp_start || pc >= sigtramp_end );
  84 }
  85
  86
  87 static _Unwind_Reason_Code
  88 x86_64_dragonfly_fallback_frame_state
  89 (struct _Unwind_Context *context, _Unwind_FrameState *fs)
  90 {
  91   struct sigframe *sf;
  92   long new_cfa;
  93
  94   if (x86_64_outside_sigtramp_range(context->ra))
  95     return _URC_END_OF_STACK;
  96
  97   sf = (struct sigframe *) context->cfa;
  98   new_cfa = sf->REG_NAME(rsp);
  99   fs->regs.cfa_how = CFA_REG_OFFSET;
 100   /* Register 7 is rsp  */
 101   fs->regs.cfa_reg = 7;
 102   fs->regs.cfa_offset = new_cfa - (long) context->cfa;
 103
 104   /* The SVR4 register numbering macros aren't usable in libgcc.  */
 105   fs->regs.how[0] = REG_SAVED_OFFSET;
 106   fs->regs.reg[0].loc.offset = (long)&sf->REG_NAME(rax) - new_cfa;
 107   fs->regs.how[1] = REG_SAVED_OFFSET;
 108   fs->regs.reg[1].loc.offset = (long)&sf->REG_NAME(rdx) - new_cfa;
 109   fs->regs.how[2] = REG_SAVED_OFFSET;
 110   fs->regs.reg[2].loc.offset = (long)&sf->REG_NAME(rcx) - new_cfa;
 111   fs->regs.how[3] = REG_SAVED_OFFSET;
 112   fs->regs.reg[3].loc.offset = (long)&sf->REG_NAME(rbx) - new_cfa;
 113   fs->regs.how[4] = REG_SAVED_OFFSET;
 114   fs->regs.reg[4].loc.offset = (long)&sf->REG_NAME(rsi) - new_cfa;
 115   fs->regs.how[5] = REG_SAVED_OFFSET;
 116   fs->regs.reg[5].loc.offset = (long)&sf->REG_NAME(rdi) - new_cfa;
 117   fs->regs.how[6] = REG_SAVED_OFFSET;
 118   fs->regs.reg[6].loc.offset = (long)&sf->REG_NAME(rbp) - new_cfa;
 119   fs->regs.how[8] = REG_SAVED_OFFSET;
 120   fs->regs.reg[8].loc.offset = (long)&sf->REG_NAME(r8) - new_cfa;
 121   fs->regs.how[9] = REG_SAVED_OFFSET;
 122   fs->regs.reg[9].loc.offset = (long)&sf->REG_NAME(r9) - new_cfa;
 123   fs->regs.how[10] = REG_SAVED_OFFSET;
 124   fs->regs.reg[10].loc.offset = (long)&sf->REG_NAME(r10) - new_cfa;
 125   fs->regs.how[11] = REG_SAVED_OFFSET;
 126   fs->regs.reg[11].loc.offset = (long)&sf->REG_NAME(r11) - new_cfa;
 127   fs->regs.how[12] = REG_SAVED_OFFSET;
 128   fs->regs.reg[12].loc.offset = (long)&sf->REG_NAME(r12) - new_cfa;
 129   fs->regs.how[13] = REG_SAVED_OFFSET;
 130   fs->regs.reg[13].loc.offset = (long)&sf->REG_NAME(r13) - new_cfa;
 131   fs->regs.how[14] = REG_SAVED_OFFSET;
 132   fs->regs.reg[14].loc.offset = (long)&sf->REG_NAME(r14) - new_cfa;
 133   fs->regs.how[15] = REG_SAVED_OFFSET;
 134   fs->regs.reg[15].loc.offset = (long)&sf->REG_NAME(r15) - new_cfa;
 135   fs->regs.how[16] = REG_SAVED_OFFSET;
 136   fs->regs.reg[16].loc.offset = (long)&sf->REG_NAME(rip) - new_cfa;
 137   fs->retaddr_column = 16;
 138   fs->signal_frame = 1;
 139   return _URC_NO_REASON;
 140 }
 141
 142 #else /* Next section is for i386  */
 143
 144 #define MD_FALLBACK_FRAME_STATE_FOR x86_dragonfly_fallback_frame_state
 145
 146
 147 static void
 148 x86_sigtramp_range (unsigned char **start, unsigned char **end)
 149 {
 150   unsigned long ps_strings;
 151   int mib[2];
 152   size_t len;
 153
 154   mib[0] = CTL_KERN;
 155   mib[1] = KERN_PS_STRINGS;
 156   len = sizeof (ps_strings);
 157   sysctl (mib, 2, &ps_strings, &len, NULL, 0);
 158
 159   *start = (unsigned char *)ps_strings - 128;
 160   *end   = (unsigned char *)ps_strings;
 161 }
 162
 163
 164 static _Unwind_Reason_Code
 165 x86_dragonfly_fallback_frame_state
 166 (struct _Unwind_Context *context, _Unwind_FrameState *fs)
 167 {
 168   unsigned char *pc = context->ra;
 169   unsigned char *sigtramp_start, *sigtramp_end;
 170   struct sigframe *sf;
 171   long new_cfa;
 172
 173   x86_sigtramp_range(&sigtramp_start, &sigtramp_end);
 174
 175   if (pc >= sigtramp_end || pc < sigtramp_start)
 176     return _URC_END_OF_STACK;
 177
 178   sf = (struct sigframe *) context->cfa;
 179   new_cfa = sf->REG_NAME(esp);
 180   fs->regs.cfa_how = CFA_REG_OFFSET;
 181   fs->regs.cfa_reg = 4;
 182   fs->regs.cfa_offset = new_cfa - (long) context->cfa;
 183
 184   /* The SVR4 register numbering macros aren't usable in libgcc.  */
 185   fs->regs.how[0] = REG_SAVED_OFFSET;
 186   fs->regs.reg[0].loc.offset = (long)&sf->REG_NAME(eax) - new_cfa;
 187   fs->regs.how[3] = REG_SAVED_OFFSET;
 188   fs->regs.reg[3].loc.offset = (long)&sf->REG_NAME(ebx) - new_cfa;
 189   fs->regs.how[1] = REG_SAVED_OFFSET;
 190   fs->regs.reg[1].loc.offset = (long)&sf->REG_NAME(ecx) - new_cfa;
 191   fs->regs.how[2] = REG_SAVED_OFFSET;
 192   fs->regs.reg[2].loc.offset = (long)&sf->REG_NAME(edx) - new_cfa;
 193   fs->regs.how[6] = REG_SAVED_OFFSET;
 194   fs->regs.reg[6].loc.offset = (long)&sf->REG_NAME(esi) - new_cfa;
 195   fs->regs.how[7] = REG_SAVED_OFFSET;
 196   fs->regs.reg[7].loc.offset = (long)&sf->REG_NAME(edi) - new_cfa;
 197   fs->regs.how[5] = REG_SAVED_OFFSET;
 198   fs->regs.reg[5].loc.offset = (long)&sf->REG_NAME(ebp) - new_cfa;
 199   fs->regs.how[8] = REG_SAVED_OFFSET;
 200   fs->regs.reg[8].loc.offset = (long)&sf->REG_NAME(eip) - new_cfa;
 201   fs->retaddr_column = 8;
 202   fs->signal_frame = 1;
 203   return _URC_NO_REASON;
 204 }
 205 #endif /* ifdef __x86_64__  */