mips-tdep.c

早期freebsd实现

	write_memory (save_address, (char *)&buffer, 4);
	save_address -= 4;
      }
  write_register (PUSH_FP_REGNUM, sp);
  PROC_FRAME_REG(proc_desc) = PUSH_FP_REGNUM;
  PROC_FRAME_OFFSET(proc_desc) = 0;
  buffer = read_register (PC_REGNUM);
  write_memory (sp - 4, (char *)&buffer, sizeof(REGISTER_TYPE));
  buffer = read_register (HI_REGNUM);
  write_memory (sp - 8, (char *)&buffer, sizeof(REGISTER_TYPE));
  buffer = read_register (LO_REGNUM);
  write_memory (sp - 12, (char *)&buffer, sizeof(REGISTER_TYPE));
  buffer = read_register (FCRCS_REGNUM);
  write_memory (sp - 16, (char *)&buffer, sizeof(REGISTER_TYPE));
  sp -= 4 * (GEN_REG_SAVE_COUNT+FLOAT_REG_SAVE_COUNT+SPECIAL_REG_SAVE_COUNT);
  write_register (SP_REGNUM, sp);
  PROC_LOW_ADDR(proc_desc) = sp - CALL_DUMMY_SIZE + CALL_DUMMY_START_OFFSET;
  PROC_HIGH_ADDR(proc_desc) = sp;
  SET_PROC_DESC_IS_DUMMY(proc_desc);
  PROC_PC_REG(proc_desc) = RA_REGNUM;
}

void
mips_pop_frame()
{
  register int regnum;
  FRAME frame = get_current_frame ();
  CORE_ADDR new_sp = frame->frame;

  mips_extra_func_info_t proc_desc = frame->proc_desc;

  write_register (PC_REGNUM, FRAME_SAVED_PC(frame));
  if (proc_desc)
    {
      for (regnum = 32; --regnum >= 0; )
	if (PROC_REG_MASK(proc_desc) & (1 << regnum))
	  write_register (regnum,
			  read_memory_integer (frame->saved_regs->regs[regnum],
					       4));
      for (regnum = 32; --regnum >= 0; )
	if (PROC_FREG_MASK(proc_desc) & (1 << regnum))
	  write_register (regnum + FP0_REGNUM,
			  read_memory_integer (frame->saved_regs->regs[regnum + FP0_REGNUM], 4));
    }
  write_register (SP_REGNUM, new_sp);
  flush_cached_frames ();
  /* We let mips_init_extra_frame_info figure out the frame pointer */
  set_current_frame (create_new_frame (0, read_pc ()));

  if (PROC_DESC_IS_DUMMY(proc_desc))
    {
      struct linked_proc_info *pi_ptr, *prev_ptr;

      for (pi_ptr = linked_proc_desc_table, prev_ptr = NULL;
	   pi_ptr != NULL;
	   prev_ptr = pi_ptr, pi_ptr = pi_ptr->next)
	{
	  if (&pi_ptr->info == proc_desc)
	    break;
	}

      if (pi_ptr == NULL)
	error ("Can't locate dummy extra frame info\n");

      if (prev_ptr != NULL)
	prev_ptr->next = pi_ptr->next;
      else
	linked_proc_desc_table = pi_ptr->next;

      free (pi_ptr);

      write_register (HI_REGNUM, read_memory_integer(new_sp - 8, 4));
      write_register (LO_REGNUM, read_memory_integer(new_sp - 12, 4));
      write_register (FCRCS_REGNUM, read_memory_integer(new_sp - 16, 4));
    }
}

static void
mips_print_register (regnum, all)
     int regnum, all;
{
      unsigned char raw_buffer[MAX_REGISTER_RAW_SIZE * 2]; /* *2 for doubles */
      REGISTER_TYPE val;

      /* Get the data in raw format.  */
      if (read_relative_register_raw_bytes (regnum, raw_buffer))
	{
	  printf_filtered ("%s: [Invalid]", reg_names[regnum]);
	  return;
	}
      
      /* If an even floating pointer register, also print as double. */
      if (regnum >= FP0_REGNUM && regnum < FP0_REGNUM+32
	  && !((regnum-FP0_REGNUM) & 1)) {
	  read_relative_register_raw_bytes (regnum+1, raw_buffer+4);
	  printf_filtered ("(d%d: ", regnum-FP0_REGNUM);
	  val_print (builtin_type_double, raw_buffer, 0,
		     stdout, 0, 1, 0, Val_pretty_default);
	  printf_filtered ("); ");
      }
      fputs_filtered (reg_names[regnum], stdout);
#ifndef NUMERIC_REG_NAMES
      if (regnum < 32)
	  printf_filtered ("(r%d): ", regnum);
      else
#endif
	  printf_filtered (": ");

      /* If virtual format is floating, print it that way.  */
      if (TYPE_CODE (REGISTER_VIRTUAL_TYPE (regnum)) == TYPE_CODE_FLT
	  && ! INVALID_FLOAT (raw_buffer, REGISTER_VIRTUAL_SIZE(regnum))) {
	  val_print (REGISTER_VIRTUAL_TYPE (regnum), raw_buffer, 0,
		     stdout, 0, 1, 0, Val_pretty_default);
      }
      /* Else print as integer in hex.  */
      else
	{
	  long val;

	  bcopy (raw_buffer, &val, sizeof (long));
	  SWAP_TARGET_AND_HOST ((char *)&val, sizeof (long));
	  if (val == 0)
	    printf_filtered ("0");
	  else if (all)
	    printf_filtered (local_hex_format(), val);
	  else
	    printf_filtered ("%s=%d", local_hex_string(val), val);
	}
}

/* Replacement for generic do_registers_info.  */
void
mips_do_registers_info (regnum, fpregs)
     int regnum;
     int fpregs;
{
  if (regnum != -1) {
      mips_print_register (regnum, 0);
      printf_filtered ("\n");
  }
  else {
      for (regnum = 0; regnum < NUM_REGS; ) {
	  if ((!fpregs) && regnum >= FP0_REGNUM && regnum <= FCRIR_REGNUM) {
	    regnum++;
	    continue;
	  }
	  mips_print_register (regnum, 1);
	  regnum++;
	  if ((regnum & 3) == 0 || regnum == NUM_REGS)
	      printf_filtered (";\n");
	  else
	      printf_filtered ("; ");
      }
  }
}
/* Return number of args passed to a frame. described by FIP.
   Can return -1, meaning no way to tell.  */

int
mips_frame_num_args(fip)
	FRAME fip;
{
#if 0
	struct chain_info_t *p;

	p = mips_find_cached_frame(FRAME_FP(fip));
	if (p->valid)
		return p->the_info.numargs;
#endif
	return -1;
}


/* Bad floats: Returns 0 if P points to a valid IEEE floating point number,
   1 if P points to a denormalized number or a NaN. LEN says whether this is
   a single-precision or double-precision float */
#define SINGLE_EXP_BITS  8
#define DOUBLE_EXP_BITS 11
int
isa_NAN(p, len)
     int *p, len;
{
  int exponent;
  if (len == 4)
    {
      exponent = *p;
      exponent = exponent << 1 >> (32 - SINGLE_EXP_BITS - 1);
      return ((exponent == -1) || (! exponent && *p));
    }
  else if (len == 8)
    {
      exponent = *(p+1);
      exponent = exponent << 1 >> (32 - DOUBLE_EXP_BITS - 1);
      return ((exponent == -1) || (! exponent && *p * *(p+1)));
    }
  else return 1;
}

/* To skip prologues, I use this predicate. Returns either PC
   itself if the code at PC does not look like a function prologue,
   PC+4 if it does (our caller does not need anything more fancy). */

CORE_ADDR
mips_skip_prologue(pc)
     CORE_ADDR pc;
{
    struct symbol *f;
    struct block *b;
    unsigned long inst;
    int offset;

    /* For -g modules and most functions anyways the
       first instruction adjusts the stack.
       But we allow some number of stores before the stack adjustment.
       (These are emitted by varags functions compiled by gcc-2.0. */
    for (offset = 0; offset < 100; offset += 4) {
	inst = read_memory_integer(pc + offset, 4);
	if ((inst & 0xffff0000) == 0x27bd0000) /* addiu $sp,$sp,offset */
	    return pc + offset + 4;
	if ((inst & 0xFFE00000) != 0xAFA00000) /* sw reg,n($sp) */
	    break;
    }

    /* Well, it looks like a frameless. Let's make sure.
       Note that we are not called on the current PC,
       but on the function`s start PC, and I have definitely
       seen optimized code that adjusts the SP quite later */
    b = block_for_pc(pc);
    if (!b) return pc;

    f = lookup_symbol(MIPS_EFI_SYMBOL_NAME, b, LABEL_NAMESPACE, 0, NULL);
    if (!f) return pc;
    /* Ideally, I would like to use the adjusted info
       from mips_frame_info(), but for all practical
       purposes it will not matter (and it would require
       a different definition of SKIP_PROLOGUE())

       Actually, it would not hurt to skip the storing
       of arguments on the stack as well. */
    if (((mips_extra_func_info_t)SYMBOL_VALUE(f))->pdr.frameoffset)
	return pc + 4;

    return pc;
}

#ifdef KERNELDEBUG
/*XXX*/
CORE_ADDR intstack_top;
CORE_ADDR intstack_bottom;

CORE_ADDR kernstack_top;
CORE_ADDR kernstack_bottom;
CORE_ADDR trap_pc_start;
CORE_ADDR trap_pc_end;

int
in_trap_handler(pc)
	CORE_ADDR pc;
{
	return (pc >= trap_pc_start && pc <= trap_pc_end);
}

int
inside_kernstack(addr)
	CORE_ADDR addr;
{
	return (addr < kernstack_top && addr >= kernstack_bottom);
}

/*
 * (re-)set the variables that make inside_kernstack() work.
 */
void
set_kernel_boundaries()
{
        if (trap_pc_start == 0) {
		trap_pc_start = ksym_lookup("trap_handler_start");
		trap_pc_end = ksym_lookup("trap_handler_end");
        }
        kernstack_bottom = UADDR + sizeof(struct user);
        kernstack_top = KERNELSTACK;
}

/*
 * Called from remote_wait, after the remote kernel has stopped.
 * Look up the current proc, and set up boundaries.
 * This is for active kernels only.
 */
void
set_curproc()
{
#ifdef notdef
	cpudata = fetch_cpudata();
#endif
	set_kernel_boundaries();
}

/*
 * Fetch registers from a crashdump or /dev/kmem.
 */
void
kvm_fetch_registers(uaddr)
	CORE_ADDR uaddr;
{
	int i;
	u_long cps, reg, sp;
	float freg;
	struct pcb pcb;

	if (target_read_memory(uaddr, (char *)&pcb, sizeof(pcb)) != 0)
		error("cannot read pcb at 0x%x", uaddr);
	/*
	 * Invalidate all the registers then fill in the ones we know about.
	 */
	registers_changed();

	for (i = 0; i < 32; ++i)
		supply_register(i, (char *)&pcb.pcb_regs[i]);
	supply_register(PC_REGNUM, (char *)&pcb.pcb_pc);
	supply_register(PS_REGNUM, (char *)&pcb.pcb_sr);
}

/*
 * Set the process context to that of the proc structure at
 * system address paddr.  Read in the register state.
 */
int
set_procaddr(addr)
	CORE_ADDR addr;
{
	if (addr == 0)
		addr = ksym_lookup("u");

#ifdef notdef
	if (addr < KERNELBASE)
		return (1);
#endif
	set_kernel_boundaries();
	kvm_fetch_registers(addr);
	return (0);
}

/*
 * Get the registers out of a crashdump or /dev/kmem.
 * XXX This somehow belongs in kcore.c.
 *
 * We just get all the registers, so we don't use regno.
 */
/* ARGSUSED */
void
kernel_core_registers(regno)
	int regno;
{
	/*
	 * Need to find current u area to get kernel stack and pcb
	 * where "panic" saved registers.
	 * (libkvm also needs to know current u area to get user
	 * address space mapping).
	 */
	/* XXX */
	(void)set_procaddr(0);
}

#endif