old-autovect-branch/gcc/config/s390/tpf-unwind.h

   1 /* DWARF2 EH unwinding support for TPF OS.
   2    Copyright (C) 2004, 2005 Free Software Foundation, Inc.
   3    Contributed by P.J. Darcy (darcypj@us.ibm.com).
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 In addition to the permissions in the GNU General Public License, the
  13 Free Software Foundation gives you unlimited permission to link the
  14 compiled version of this file into combinations with other programs,
  15 and to distribute those combinations without any restriction coming
  16 from the use of this file.  (The General Public License restrictions
  17 do apply in other respects; for example, they cover modification of
  18 the file, and distribution when not linked into a combined
  19 executable.)
  20
  21 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  22 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  23 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  24 for more details.
  25
  26 You should have received a copy of the GNU General Public License
  27 along with GCC; see the file COPYING.  If not, write to the Free
  28 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  29 02110-1301, USA.  */
  30
  31 #include <dlfcn.h>
  32
  33 /* Function Name: __isPATrange
  34    Parameters passed into it:  address to check
  35    Return Value: A 1 if address is in pat code "range", 0 if not
  36    Description: This function simply checks to see if the address
  37    passed to it is in the CP pat code range.  */
  38
  39 #define MIN_PATRANGE 0x10000
  40 #define MAX_PATRANGE 0x800000
  41
  42 static inline unsigned int
  43 __isPATrange (void *addr)
  44 {
  45   if (addr > (void *)MIN_PATRANGE && addr < (void *)MAX_PATRANGE)
  46     return 1;
  47   else
  48     return 0;
  49 }
  50
  51 /* TPF return address offset from start of stack frame.  */
  52 #define TPFRA_OFFSET 168
  53
  54 /* Exceptions macro defined for TPF so that functions without
  55    dwarf frame information can be used with exceptions.  */
  56 #define MD_FALLBACK_FRAME_STATE_FOR s390_fallback_frame_state
  57
  58 static _Unwind_Reason_Code
  59 s390_fallback_frame_state (struct _Unwind_Context *context,
  60                            _Unwind_FrameState *fs)
  61 {
  62   unsigned long int regs;
  63   unsigned long int new_cfa;
  64   int i;
  65
  66   regs = *((unsigned long int *)
  67         (((unsigned long int) context->cfa) - STACK_POINTER_OFFSET));
  68
  69   /* Are we going through special linkage code?  */
  70   if (__isPATrange (context->ra))
  71     {
  72
  73       /* Our return register isn't zero for end of stack, so
  74          check backward stackpointer to see if it is zero.  */
  75       if (regs == NULL)
  76          return _URC_END_OF_STACK;
  77
  78       /* No stack frame.  */
  79       fs->cfa_how = CFA_REG_OFFSET;
  80       fs->cfa_reg = 15;
  81       fs->cfa_offset = STACK_POINTER_OFFSET;
  82
  83       /* All registers remain unchanged ...  */
  84       for (i = 0; i < 32; i++)
  85         {
  86           fs->regs.reg[i].how = REG_SAVED_REG;
  87           fs->regs.reg[i].loc.reg = i;
  88         }
  89
  90       /* ... except for %r14, which is stored at CFA-112
  91          and used as return address.  */
  92       fs->regs.reg[14].how = REG_SAVED_OFFSET;
  93       fs->regs.reg[14].loc.offset = TPFRA_OFFSET - STACK_POINTER_OFFSET;
  94       fs->retaddr_column = 14;
  95
  96       return _URC_NO_REASON;
  97     }
  98
  99   regs = *((unsigned long int *)
 100         (((unsigned long int) context->cfa) - STACK_POINTER_OFFSET));
 101   new_cfa = regs + STACK_POINTER_OFFSET;
 102
 103   fs->cfa_how = CFA_REG_OFFSET;
 104   fs->cfa_reg = 15;
 105   fs->cfa_offset = new_cfa -
 106         (unsigned long int) context->cfa + STACK_POINTER_OFFSET;
 107
 108   for (i = 0; i < 16; i++)
 109     {
 110       fs->regs.reg[i].how = REG_SAVED_OFFSET;
 111       fs->regs.reg[i].loc.offset = regs + i*8 - new_cfa;
 112     }
 113
 114   for (i = 0; i < 4; i++)
 115     {
 116       fs->regs.reg[16 + i].how = REG_SAVED_OFFSET;
 117       fs->regs.reg[16 + i].loc.offset = regs + 16*8 + i*8 - new_cfa;
 118     }
 119
 120   fs->retaddr_column = 14;
 121
 122   return _URC_NO_REASON;
 123 }
 124
 125 /* Function Name: __tpf_eh_return
 126    Parameters passed into it: Destination address to jump to.
 127    Return Value: Converted Destination address if a Pat Stub exists.
 128    Description: This function swaps the unwinding return address
 129       with the cp stub code.  The original target return address is
 130       then stored into the tpf return address field.  The cp stub
 131       code is searched for by climbing back up the stack and
 132       comparing the tpf stored return address object address to
 133       that of the targets object address.  */
 134
 135 #define CURRENT_STACK_PTR() \
 136   ({ register unsigned long int *stack_ptr asm ("%r15"); stack_ptr; })
 137
 138 #define PREVIOUS_STACK_PTR() \
 139   ((unsigned long int *)(*(CURRENT_STACK_PTR())))
 140
 141 #define RA_OFFSET 112
 142 #define R15_OFFSET 120
 143 #define TPFAREA_OFFSET 160
 144 #define TPFAREA_SIZE STACK_POINTER_OFFSET-TPFAREA_OFFSET
 145 #define INVALID_RETURN 0
 146
 147 void * __tpf_eh_return (void *target);
 148
 149 void *
 150 __tpf_eh_return (void *target)
 151 {
 152   Dl_info targetcodeInfo, currentcodeInfo;
 153   int retval;
 154   void *current, *stackptr, *destination_frame;
 155   unsigned long int shifter, is_a_stub;
 156
 157   is_a_stub = 0;
 158
 159   /* Get code info for target return's address.  */
 160   retval = dladdr (target, &targetcodeInfo);
 161
 162   /* Ensure the code info is valid (for target).  */
 163   if (retval != INVALID_RETURN)
 164     {
 165
 166       /* Get the stack pointer of the stack frame to be modified by
 167          the exception unwinder.  So that we can begin our climb
 168          there.  */
 169       stackptr = (void *) *((unsigned long int *) (*(PREVIOUS_STACK_PTR())));
 170
 171       /* Begin looping through stack frames.  Stop if invalid
 172          code information is retrieved or if a match between the
 173          current stack frame iteration shared object's address
 174          matches that of the target, calculated above.  */
 175       do
 176         {
 177           /* Get return address based on our stackptr iterator.  */
 178           current = (void *) *((unsigned long int *)
 179                       (stackptr+RA_OFFSET));
 180
 181           /* Is it a Pat Stub?  */
 182           if (__isPATrange (current))
 183             {
 184               /* Yes it was, get real return address
 185                  in TPF stack area.  */
 186               current = (void *) *((unsigned long int *)
 187                           (stackptr+TPFRA_OFFSET));
 188               is_a_stub = 1;
 189             }
 190
 191           /* Get codeinfo on RA so that we can figure out
 192              the module address.  */
 193           retval = dladdr (current, &currentcodeInfo);
 194
 195           /* Check that codeinfo for current stack frame is valid.
 196              Then compare the module address of current stack frame
 197              to target stack frame to determine if we have the pat
 198              stub address we want.  Also ensure we are dealing
 199              with a module crossing, stub return address. */
 200           if (is_a_stub && retval != INVALID_RETURN
 201              && targetcodeInfo.dli_fbase == currentcodeInfo.dli_fbase)
 202              {
 203                /* Yes! They are in the same module.
 204                   Force copy of TPF private stack area to
 205                   destination stack frame TPF private area. */
 206                destination_frame = (void *) *((unsigned long int *)
 207                    (*PREVIOUS_STACK_PTR() + R15_OFFSET));
 208
 209                /* Copy TPF linkage area from current frame to
 210                   destination frame.  */
 211                memcpy((void *) (destination_frame + TPFAREA_OFFSET),
 212                  (void *) (stackptr + TPFAREA_OFFSET), TPFAREA_SIZE);
 213
 214                /* Now overlay the
 215                   real target address into the TPF stack area of
 216                   the target frame we are jumping to.  */
 217                *((unsigned long int *) (destination_frame +
 218                    TPFRA_OFFSET)) = (unsigned long int) target;
 219
 220                /* Before returning the desired pat stub address to
 221                   the exception handling unwinder so that it can
 222                   actually do the "leap" shift out the low order
 223                   bit designated to determine if we are in 64BIT mode.
 224                   This is necessary for CTOA stubs.
 225                   Otherwise we leap one byte past where we want to
 226                   go to in the TPF pat stub linkage code.  */
 227                shifter = *((unsigned long int *)
 228                      (stackptr + RA_OFFSET));
 229
 230                shifter &= ~1ul;
 231
 232                /* Store Pat Stub Address in destination Stack Frame.  */
 233                *((unsigned long int *) (destination_frame +
 234                    RA_OFFSET)) = shifter;
 235
 236                /* Re-adjust pat stub address to go to correct place
 237                   in linkage.  */
 238                shifter = shifter - 4;
 239
 240                return (void *) shifter;
 241              }
 242
 243           /* Desired module pat stub not found ...
 244              Bump stack frame iterator.  */
 245           stackptr = (void *) *(unsigned long int *) stackptr;
 246
 247           is_a_stub = 0;
 248
 249         }  while (stackptr && retval != INVALID_RETURN
 250                 && targetcodeInfo.dli_fbase != currentcodeInfo.dli_fbase);
 251     }
 252
 253   /* No pat stub found, could be a problem?  Simply return unmodified
 254      target address.  */
 255   return target;
 256 }
 257