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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgcc/] [config/] [s390/] [tpf-unwind.h] - Blame information for rev 734

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1 734 jeremybenn
/* DWARF2 EH unwinding support for TPF OS.
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   Copyright (C) 2004, 2005, 2009 Free Software Foundation, Inc.
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   Contributed by P.J. Darcy (darcypj@us.ibm.com).
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
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<http://www.gnu.org/licenses/>.  */
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#include <dlfcn.h>
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/* Function Name: __isPATrange
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   Parameters passed into it:  address to check
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   Return Value: A 1 if address is in pat code "range", 0 if not
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   Description: This function simply checks to see if the address
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   passed to it is in the CP pat code range.  */
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#define MIN_PATRANGE 0x10000
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#define MAX_PATRANGE 0x800000
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static inline unsigned int
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__isPATrange (void *addr)
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{
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  if (addr > (void *)MIN_PATRANGE && addr < (void *)MAX_PATRANGE)
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    return 1;
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  else
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    return 0;
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}
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/* TPF return address offset from start of stack frame.  */
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#define TPFRA_OFFSET 168
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/* Exceptions macro defined for TPF so that functions without
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   dwarf frame information can be used with exceptions.  */
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#define MD_FALLBACK_FRAME_STATE_FOR s390_fallback_frame_state
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static _Unwind_Reason_Code
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s390_fallback_frame_state (struct _Unwind_Context *context,
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                           _Unwind_FrameState *fs)
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{
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  unsigned long int regs;
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  unsigned long int new_cfa;
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  int i;
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  regs = *((unsigned long int *)
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        (((unsigned long int) context->cfa) - STACK_POINTER_OFFSET));
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  /* Are we going through special linkage code?  */
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  if (__isPATrange (context->ra))
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    {
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      /* Our return register isn't zero for end of stack, so
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         check backward stackpointer to see if it is zero.  */
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      if (regs == NULL)
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         return _URC_END_OF_STACK;
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      /* No stack frame.  */
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      fs->regs.cfa_how = CFA_REG_OFFSET;
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      fs->regs.cfa_reg = 15;
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      fs->regs.cfa_offset = STACK_POINTER_OFFSET;
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      /* All registers remain unchanged ...  */
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      for (i = 0; i < 32; i++)
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        {
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          fs->regs.reg[i].how = REG_SAVED_REG;
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          fs->regs.reg[i].loc.reg = i;
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        }
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      /* ... except for %r14, which is stored at CFA-112
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         and used as return address.  */
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      fs->regs.reg[14].how = REG_SAVED_OFFSET;
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      fs->regs.reg[14].loc.offset = TPFRA_OFFSET - STACK_POINTER_OFFSET;
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      fs->retaddr_column = 14;
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      return _URC_NO_REASON;
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    }
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  regs = *((unsigned long int *)
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        (((unsigned long int) context->cfa) - STACK_POINTER_OFFSET));
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  new_cfa = regs + STACK_POINTER_OFFSET;
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  fs->regs.cfa_how = CFA_REG_OFFSET;
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  fs->regs.cfa_reg = 15;
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  fs->regs.cfa_offset = new_cfa -
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        (unsigned long int) context->cfa + STACK_POINTER_OFFSET;
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  for (i = 0; i < 16; i++)
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    {
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      fs->regs.reg[i].how = REG_SAVED_OFFSET;
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      fs->regs.reg[i].loc.offset = regs + i*8 - new_cfa;
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    }
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  for (i = 0; i < 4; i++)
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    {
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      fs->regs.reg[16 + i].how = REG_SAVED_OFFSET;
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      fs->regs.reg[16 + i].loc.offset = regs + 16*8 + i*8 - new_cfa;
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    }
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  fs->retaddr_column = 14;
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  return _URC_NO_REASON;
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}
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/* Function Name: __tpf_eh_return
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   Parameters passed into it: Destination address to jump to.
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   Return Value: Converted Destination address if a Pat Stub exists.
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   Description: This function swaps the unwinding return address
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      with the cp stub code.  The original target return address is
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      then stored into the tpf return address field.  The cp stub
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      code is searched for by climbing back up the stack and
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      comparing the tpf stored return address object address to
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      that of the targets object address.  */
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#define CURRENT_STACK_PTR() \
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  ({ register unsigned long int *stack_ptr asm ("%r15"); stack_ptr; })
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#define PREVIOUS_STACK_PTR() \
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  ((unsigned long int *)(*(CURRENT_STACK_PTR())))
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#define RA_OFFSET 112
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#define R15_OFFSET 120
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#define TPFAREA_OFFSET 160
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#define TPFAREA_SIZE STACK_POINTER_OFFSET-TPFAREA_OFFSET
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#define INVALID_RETURN 0
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void * __tpf_eh_return (void *target);
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void *
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__tpf_eh_return (void *target)
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{
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  Dl_info targetcodeInfo, currentcodeInfo;
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  int retval;
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  void *current, *stackptr, *destination_frame;
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  unsigned long int shifter, is_a_stub;
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  is_a_stub = 0;
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  /* Get code info for target return's address.  */
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  retval = dladdr (target, &targetcodeInfo);
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  /* Ensure the code info is valid (for target).  */
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  if (retval != INVALID_RETURN)
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    {
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      /* Get the stack pointer of the stack frame to be modified by
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         the exception unwinder.  So that we can begin our climb
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         there.  */
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      stackptr = (void *) *((unsigned long int *) (*(PREVIOUS_STACK_PTR())));
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      /* Begin looping through stack frames.  Stop if invalid
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         code information is retrieved or if a match between the
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         current stack frame iteration shared object's address
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         matches that of the target, calculated above.  */
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      do
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        {
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          /* Get return address based on our stackptr iterator.  */
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          current = (void *) *((unsigned long int *)
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                      (stackptr+RA_OFFSET));
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          /* Is it a Pat Stub?  */
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          if (__isPATrange (current))
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            {
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              /* Yes it was, get real return address
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                 in TPF stack area.  */
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              current = (void *) *((unsigned long int *)
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                          (stackptr+TPFRA_OFFSET));
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              is_a_stub = 1;
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            }
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          /* Get codeinfo on RA so that we can figure out
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             the module address.  */
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          retval = dladdr (current, &currentcodeInfo);
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          /* Check that codeinfo for current stack frame is valid.
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             Then compare the module address of current stack frame
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             to target stack frame to determine if we have the pat
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             stub address we want.  Also ensure we are dealing
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             with a module crossing, stub return address. */
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          if (is_a_stub && retval != INVALID_RETURN
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             && targetcodeInfo.dli_fbase == currentcodeInfo.dli_fbase)
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             {
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               /* Yes! They are in the same module.
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                  Force copy of TPF private stack area to
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                  destination stack frame TPF private area. */
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               destination_frame = (void *) *((unsigned long int *)
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                   (*PREVIOUS_STACK_PTR() + R15_OFFSET));
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               /* Copy TPF linkage area from current frame to
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                  destination frame.  */
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               memcpy((void *) (destination_frame + TPFAREA_OFFSET),
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                 (void *) (stackptr + TPFAREA_OFFSET), TPFAREA_SIZE);
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               /* Now overlay the
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                  real target address into the TPF stack area of
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                  the target frame we are jumping to.  */
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               *((unsigned long int *) (destination_frame +
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                   TPFRA_OFFSET)) = (unsigned long int) target;
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               /* Before returning the desired pat stub address to
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                  the exception handling unwinder so that it can
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                  actually do the "leap" shift out the low order
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                  bit designated to determine if we are in 64BIT mode.
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                  This is necessary for CTOA stubs.
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                  Otherwise we leap one byte past where we want to
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                  go to in the TPF pat stub linkage code.  */
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               shifter = *((unsigned long int *)
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                     (stackptr + RA_OFFSET));
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               shifter &= ~1ul;
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               /* Store Pat Stub Address in destination Stack Frame.  */
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               *((unsigned long int *) (destination_frame +
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                   RA_OFFSET)) = shifter;
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               /* Re-adjust pat stub address to go to correct place
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                  in linkage.  */
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               shifter = shifter - 4;
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235
               return (void *) shifter;
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             }
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          /* Desired module pat stub not found ...
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             Bump stack frame iterator.  */
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          stackptr = (void *) *(unsigned long int *) stackptr;
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          is_a_stub = 0;
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244
        }  while (stackptr && retval != INVALID_RETURN
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                && targetcodeInfo.dli_fbase != currentcodeInfo.dli_fbase);
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    }
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  /* No pat stub found, could be a problem?  Simply return unmodified
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     target address.  */
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  return target;
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}
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