text: /*
   *  linux/arch/m68k/kernel/ptrace.c
   *
   *  Copyright (C) 1994 by Hamish Macdonald
   *  Taken from linux/kernel/ptrace.c and modified for M680x0.
   *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
   *
   * This file is subject to the terms and conditions of the GNU General
   * Public License.  See the file COPYING in the main directory of
   * this archive for more details.
   */
  
  #include <linux/kernel.h>
  #include <linux/sched.h>
  #include <linux/mm.h>
  #include <linux/smp.h>
  #include <linux/errno.h>
  #include <linux/ptrace.h>
  #include <linux/user.h>
  #include <linux/signal.h>
  
  #include <asm/uaccess.h>
  #include <asm/page.h>
  #include <asm/pgtable.h>
  #include <asm/system.h>
  #include <asm/processor.h>
  
  /*
   * does not yet catch signals sent when the child dies.
   * in exit.c or in signal.c.
   */
  
  /* determines which bits in the SR the user has access to. */
  /* 1 = access 0 = no access */
  #define SR_MASK 0x001f
  
  /* sets the trace bits. */
  #define TRACE_BITS 0x8000
  
  /* Find the stack offset for a register, relative to thread.esp0. */
  #define PT_REG(reg)	((long)&((struct pt_regs *)0)->reg)
  #define SW_REG(reg)	((long)&((struct switch_stack *)0)->reg \
  			 - sizeof(struct switch_stack))
  /* Mapping from PT_xxx to the stack offset at which the register is
     saved.  Notice that usp has no stack-slot and needs to be treated
     specially (see get_reg/put_reg below). */
  static int regoff[] = {
  	[0]	= PT_REG(d1),
  	[1]	= PT_REG(d2),
  	[2]	= PT_REG(d3),
  	[3]	= PT_REG(d4),
  	[4]	= PT_REG(d5),
  	[5]	= SW_REG(d6),
  	[6]	= SW_REG(d7),
  	[7]	= PT_REG(a0),
  	[8]	= PT_REG(a1),
  	[9]	= PT_REG(a2),
  	[10]	= SW_REG(a3),
  	[11]	= SW_REG(a4),
  	[12]	= SW_REG(a5),
  	[13]	= SW_REG(a6),
  	[14]	= PT_REG(d0),
  	[15]	= -1,
  	[16]	= PT_REG(orig_d0),
  	[17]	= PT_REG(sr),
  	[18]	= PT_REG(pc),
  };
  
  /*
   * Get contents of register REGNO in task TASK.
   */
  static inline long get_reg(struct task_struct *task, int regno)
  {
  	unsigned long *addr;
  
  	if (regno == PT_USP)
  		addr = &task->thread.usp;
  	else if (regno < ARRAY_SIZE(regoff))
  		addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
  	else
  		return 0;
  	return *addr;
  }
  
  /*
   * Write contents of register REGNO in task TASK.
   */
  static inline int put_reg(struct task_struct *task, int regno,
  			  unsigned long data)
  {
  	unsigned long *addr;
  
  	if (regno == PT_USP)
  		addr = &task->thread.usp;
  	else if (regno < ARRAY_SIZE(regoff))
  		addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
  	else
  		return -1;
  	*addr = data;
  	return 0;
  }
  
  /*
   * Make sure the single step bit is not set.
   */
  static inline void singlestep_disable(struct task_struct *child)
  {
  	unsigned long tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
  	put_reg(child, PT_SR, tmp);
  	clear_tsk_thread_flag(child, TIF_DELAYED_TRACE);
  }
  
  /*
   * Called by kernel/ptrace.c when detaching..
   */
  void ptrace_disable(struct task_struct *child)
  {
  	singlestep_disable(child);
  	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
  }
  
  long arch_ptrace(struct task_struct *child, long request, long addr, long data)
  {
  	unsigned long tmp;
  	int i, ret = 0;
  
  	switch (request) {
  	/* when I and D space are separate, these will need to be fixed. */
  	case PTRACE_PEEKTEXT:	/* read word at location addr. */
  	case PTRACE_PEEKDATA:
  		i = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
  		if (i != sizeof(tmp))
  			goto out_eio;
  		ret = put_user(tmp, (unsigned long *)data);
  		break;
  
  	/* read the word at location addr in the USER area. */
  	case PTRACE_PEEKUSR:
  		if (addr & 3)
  			goto out_eio;
  		addr >>= 2;	/* temporary hack. */
  
  		if (addr >= 0 && addr < 19) {
  			tmp = get_reg(child, addr);
  			if (addr == PT_SR)
  				tmp >>= 16;
  		} else if (addr >= 21 && addr < 49) {
  			tmp = child->thread.fp[addr - 21];
  			/* Convert internal fpu reg representation
  			 * into long double format
  			 */
  			if (FPU_IS_EMU && (addr < 45) && !(addr % 3))
  				tmp = ((tmp & 0xffff0000) << 15) |
  				      ((tmp & 0x0000ffff) << 16);
  		} else
  			break;
  		ret = put_user(tmp, (unsigned long *)data);
  		break;
  
  	/* when I and D space are separate, this will have to be fixed. */
  	case PTRACE_POKETEXT:	/* write the word at location addr. */
  	case PTRACE_POKEDATA:
  		if (access_process_vm(child, addr, &data, sizeof(data), 1) != sizeof(data))
  			goto out_eio;
  		break;
  
  	case PTRACE_POKEUSR:	/* write the word at location addr in the USER area */
  		if (addr & 3)
  			goto out_eio;
  		addr >>= 2;	/* temporary hack. */
  
  		if (addr == PT_SR) {
  			data &= SR_MASK;
  			data <<= 16;
  			data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
  		} else if (addr >= 0 && addr < 19) {
  			if (put_reg(child, addr, data))
  				goto out_eio;
  		} else if (addr >= 21 && addr < 48) {
  			/* Convert long double format
  			 * into internal fpu reg representation
  			 */
  			if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) {
  				data = (unsigned long)data << 15;
  				data = (data & 0xffff0000) |
  				       ((data & 0x0000ffff) >> 1);
  			}
  			child->thread.fp[addr - 21] = data;
  		} else
  			goto out_eio;
  		break;
  
  	case PTRACE_SYSCALL:	/* continue and stop at next (return from) syscall */
  	case PTRACE_CONT:	/* restart after signal. */
  		if (!valid_signal(data))
  			goto out_eio;
  
  		if (request == PTRACE_SYSCALL)
  			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
  		else
  			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
  		child->exit_code = data;
  		singlestep_disable(child);
  		wake_up_process(child);
  		break;
  
  	/*
  	 * make the child exit.  Best I can do is send it a sigkill.
  	 * perhaps it should be put in the status that it wants to
  	 * exit.
  	 */
  	case PTRACE_KILL:
  		if (child->exit_state == EXIT_ZOMBIE) /* already dead */
  			break;
  		child->exit_code = SIGKILL;
  		singlestep_disable(child);
  		wake_up_process(child);
  		break;
  
  	case PTRACE_SINGLESTEP:	/* set the trap flag. */
  		if (!valid_signal(data))
  			goto out_eio;
  
  		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
  		tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
  		put_reg(child, PT_SR, tmp);
  		set_tsk_thread_flag(child, TIF_DELAYED_TRACE);
  
  		child->exit_code = data;
  		/* give it a chance to run. */
  		wake_up_process(child);
  		break;
  
  	case PTRACE_DETACH:	/* detach a process that was attached. */
  		ret = ptrace_detach(child, data);
  		break;
  
  	case PTRACE_GETREGS:	/* Get all gp regs from the child. */
  		for (i = 0; i < 19; i++) {
  			tmp = get_reg(child, i);
  			if (i == PT_SR)
  				tmp >>= 16;
  			ret = put_user(tmp, (unsigned long *)data);
  			if (ret)
  				break;
  			data += sizeof(long);
  		}
  		break;
  
  	case PTRACE_SETREGS:	/* Set all gp regs in the child. */
  		for (i = 0; i < 19; i++) {
  			ret = get_user(tmp, (unsigned long *)data);
  			if (ret)
  				break;
  			if (i == PT_SR) {
  				tmp &= SR_MASK;
  				tmp <<= 16;
  				tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
  			}
  			put_reg(child, i, tmp);
  			data += sizeof(long);
  		}
  		break;
  
  	case PTRACE_GETFPREGS:	/* Get the child FPU state. */
  		if (copy_to_user((void *)data, &child->thread.fp,
  				 sizeof(struct user_m68kfp_struct)))
  			ret = -EFAULT;
  		break;
  
  	case PTRACE_SETFPREGS:	/* Set the child FPU state. */
  		if (copy_from_user(&child->thread.fp, (void *)data,
  				   sizeof(struct user_m68kfp_struct)))
  			ret = -EFAULT;
  		break;
  
  	default:
  		ret = ptrace_request(child, request, addr, data);
  		break;
  	}
  
  	return ret;
  out_eio:
  	return -EIO;
  }
  
  asmlinkage void syscall_trace(void)
  {
  	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
  				 ? 0x80 : 0));
  	/*
  	 * this isn't the same as continuing with a signal, but it will do
  	 * for normal use.  strace only continues with a signal if the
  	 * stopping signal is not SIGTRAP.  -brl
  	 */
  	if (current->exit_code) {
  		send_sig(current->exit_code, current, 1);
  		current->exit_code = 0;
  	}
  }
  