libunwind-eh_elf/src/_UPT_access_reg.c

/* libunwind - a platform-independent unwind library
   Copyright (C) 2003 Hewlett-Packard Co
	Contributed by David Mosberger-Tang <davidm@hpl.hp.com>

This file is part of libunwind.

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */

#include "_UPT_internal.h"

#if UNW_TARGET_IA64
# include <elf.h>
# include <asm/ptrace_offsets.h>
# include "ia64/rse.h"
#endif

int
_UPT_access_reg (unw_addr_space_t as, unw_regnum_t reg, unw_word_t *val,
		 int write, void *arg)
{
  struct UPT_info *ui = arg;
  pid_t pid = ui->pid;

#if DEBUG
  if (write)
    debug (100, "%s: %s <- %lx\n", __FUNCTION__ unw_regname (reg), *val);
#endif

#if UNW_TARGET_IA64
  if ((unsigned) reg - UNW_IA64_NAT < 32)
    {
      unsigned long nat_bits, mask;

      /* The Linux ptrace represents the statc NaT bits as a single word.  */
      mask = ((unw_word_t) 1) << (reg - UNW_IA64_NAT);
      errno = 0;
      nat_bits = ptrace (PTRACE_PEEKUSER, pid, PT_NAT_BITS, 0);
      if (errno)
	return -UNW_EBADREG;

      if (write)
	{
	  if (*val)
	    nat_bits |= mask;
	  else
	    nat_bits &= ~mask;
	  errno = 0;
	  ptrace (PTRACE_POKEUSER, pid, PT_NAT_BITS, nat_bits);
	  if (errno)
	    return -UNW_EBADREG;
	}
      goto out;
    }
  else
    switch (reg)
      {
      case UNW_REG_IP:
	{
	  unsigned long ip, psr;

	  /* distribute bundle-addr. & slot-number across PT_IIP & PT_IPSR.  */
	  errno = 0;
	  psr = ptrace (PTRACE_PEEKUSER, pid, PT_CR_IPSR, 0);
	  if (errno)
	    return -UNW_EBADREG;
	  if (write)
	    {
	      ip = *val & ~0xfUL;
	      psr = (psr & ~0x3UL << 41) | (*val & 0x3);
	      errno = 0;
	      ptrace (PTRACE_POKEUSER, pid, PT_CR_IIP, ip);
	      ptrace (PTRACE_POKEUSER, pid, PT_CR_IPSR, psr);
	      if (errno)
		return -UNW_EBADREG;
	    }
	  else
	    {
	      errno = 0;
	      ip = ptrace (PTRACE_PEEKUSER, pid, PT_CR_IIP, 0);
	      if (errno)
		return -UNW_EBADREG;
	      *val = ip + ((psr >> 41) & 0x3);
	    }
	  goto out;
	}

      case UNW_IA64_AR_BSPSTORE:
	reg = UNW_IA64_AR_BSP;
	break;

      case UNW_IA64_AR_BSP:
      case UNW_IA64_BSP:
	{
	  unsigned long sof, cfm, bsp;

	  /* Account for the fact that ptrace() expects bsp to point
	     _after_ the current register frame.  */
	  errno = 0;
	  cfm = ptrace (PTRACE_PEEKUSER, pid, PT_CFM, 0);
	  if (errno)
	    return -UNW_EBADREG;
	  sof = (cfm & 0x7f);

	  if (write)
	    {
	      bsp = ia64_rse_skip_regs (*val, sof);
	      errno = 0;
	      ptrace (PTRACE_POKEUSER, pid, PT_AR_BSP, bsp);
	      if (errno)
		return -UNW_EBADREG;
	    }
	  else
	    {
	      errno = 0;
	      bsp = ptrace (PTRACE_PEEKUSER, pid, PT_AR_BSP, 0);
	      if (errno)
		return -UNW_EBADREG;
	      *val = ia64_rse_skip_regs (bsp, -sof);
	    }
	  goto out;
	}

      case UNW_IA64_CFM:
	/* If we change CFM, we need to adjust ptrace's notion of bsp
	   accordingly, so that the real bsp remains unchanged.  */
	if (write)
	  {
	    unsigned long new_sof, old_sof, cfm, bsp;

	    errno = 0;
	    bsp = ptrace (PTRACE_PEEKUSER, pid, PT_AR_BSP, 0);
	    cfm = ptrace (PTRACE_PEEKUSER, pid, PT_CFM, 0);
	    if (errno)
	      return -UNW_EBADREG;
	    old_sof = (cfm & 0x7f);
	    new_sof = (*val & 0x7f);
	    if (old_sof != new_sof)
	      {
		bsp = ia64_rse_skip_regs (bsp, -old_sof + new_sof);
		errno = 0;
		ptrace (PTRACE_POKEUSER, pid, PT_AR_BSP, 0);
		if (errno)
		  return -UNW_EBADREG;
	      }
	    errno = 0;
	    ptrace (PTRACE_POKEUSER, pid, PT_CFM, *val);
	    if (errno)
	      return -UNW_EBADREG;
	    goto out;
	  }
	break;
      }
#endif

  if ((unsigned) reg >= sizeof (_UPT_reg_offset) / sizeof (_UPT_reg_offset[0]))
    return -UNW_EBADREG;

  errno = 0;
  if (write)
    ptrace (PTRACE_POKEUSER, pid, _UPT_reg_offset[reg], *val);
  else
    *val = ptrace (PTRACE_PEEKUSER, pid, _UPT_reg_offset[reg], 0);
  if (errno)
    return -UNW_EBADREG;

 out:
#if DEBUG
  if (!write)
    debug (100, "%s: %s -> %lx\n", __FUNCTION__ unw_regname (reg), *val);
#endif
  return 0;
}