/*
 *  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);
}

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:
                ret = generic_ptrace_peekdata(child, addr, 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:
                ret = generic_ptrace_pokedata(child, addr, data);
                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_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;
        }
}