/*
 * Copyright 2010 Tilera Corporation. All Rights Reserved.
 *
 *   This program is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU General Public License
 *   as published by the Free Software Foundation, version 2.
 *
 *   This program is distributed in the hope that it will be useful, but
 *   WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 *   NON INFRINGEMENT.  See the GNU General Public License for
 *   more details.
 *
 * Copied from i386: Ross Biro 1/23/92
 */

#include <linux/kernel.h>
#include <linux/ptrace.h>
#include <linux/kprobes.h>
#include <linux/compat.h>
#include <linux/uaccess.h>
#include <asm/traps.h>

void user_enable_single_step(struct task_struct *child)
{
        set_tsk_thread_flag(child, TIF_SINGLESTEP);
}

void user_disable_single_step(struct task_struct *child)
{
        clear_tsk_thread_flag(child, TIF_SINGLESTEP);
}

/*
 * Called by kernel/ptrace.c when detaching..
 */
void ptrace_disable(struct task_struct *child)
{
        clear_tsk_thread_flag(child, TIF_SINGLESTEP);

        /*
         * These two are currently unused, but will be set by arch_ptrace()
         * and used in the syscall assembly when we do support them.
         */
        clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
}

long arch_ptrace(struct task_struct *child, long request,
                 unsigned long addr, unsigned long data)
{
        unsigned long __user *datap = (long __user __force *)data;
        unsigned long tmp;
        long ret = -EIO;
        char *childreg;
        struct pt_regs copyregs;
        int ex1_offset;

        switch (request) {

        case PTRACE_PEEKUSR:  /* Read register from pt_regs. */
                if (addr >= PTREGS_SIZE)
                        break;
                childreg = (char *)task_pt_regs(child) + addr;
#ifdef CONFIG_COMPAT
                if (is_compat_task()) {
                        if (addr & (sizeof(compat_long_t)-1))
                                break;
                        ret = put_user(*(compat_long_t *)childreg,
                                       (compat_long_t __user *)datap);
                } else
#endif
                {
                        if (addr & (sizeof(long)-1))
                                break;
                        ret = put_user(*(long *)childreg, datap);
                }
                break;

        case PTRACE_POKEUSR:  /* Write register in pt_regs. */
                if (addr >= PTREGS_SIZE)
                        break;
                childreg = (char *)task_pt_regs(child) + addr;

                /* Guard against overwrites of the privilege level. */
                ex1_offset = PTREGS_OFFSET_EX1;
#if defined(CONFIG_COMPAT) && defined(__BIG_ENDIAN)
                if (is_compat_task())   /* point at low word */
                        ex1_offset += sizeof(compat_long_t);
#endif
                if (addr == ex1_offset)
                        data = PL_ICS_EX1(USER_PL, EX1_ICS(data));

#ifdef CONFIG_COMPAT
                if (is_compat_task()) {
                        if (addr & (sizeof(compat_long_t)-1))
                                break;
                        *(compat_long_t *)childreg = data;
                } else
#endif
                {
                        if (addr & (sizeof(long)-1))
                                break;
                        *(long *)childreg = data;
                }
                ret = 0;
                break;

        case PTRACE_GETREGS:  /* Get all registers from the child. */
                if (copy_to_user(datap, task_pt_regs(child),
                                 sizeof(struct pt_regs)) == 0) {
                        ret = 0;
                }
                break;

        case PTRACE_SETREGS:  /* Set all registers in the child. */
                if (copy_from_user(&copyregs, datap,
                                   sizeof(struct pt_regs)) == 0) {
                        copyregs.ex1 =
                                PL_ICS_EX1(USER_PL, EX1_ICS(copyregs.ex1));
                        *task_pt_regs(child) = copyregs;
                        ret = 0;
                }
                break;

        case PTRACE_GETFPREGS:  /* Get the child FPU state. */
        case PTRACE_SETFPREGS:  /* Set the child FPU state. */
                break;

        case PTRACE_SETOPTIONS:
                /* Support TILE-specific ptrace options. */
                child->ptrace &= ~PT_TRACE_MASK_TILE;
                tmp = data & PTRACE_O_MASK_TILE;
                data &= ~PTRACE_O_MASK_TILE;
                ret = ptrace_request(child, request, addr, data);
                if (tmp & PTRACE_O_TRACEMIGRATE)
                        child->ptrace |= PT_TRACE_MIGRATE;
                break;

        default:
#ifdef CONFIG_COMPAT
                if (task_thread_info(current)->status & TS_COMPAT) {
                        ret = compat_ptrace_request(child, request,
                                                    addr, data);
                        break;
                }
#endif
                ret = ptrace_request(child, request, addr, data);
                break;
        }

        return ret;
}

#ifdef CONFIG_COMPAT
/* Not used; we handle compat issues in arch_ptrace() directly. */
long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
                               compat_ulong_t addr, compat_ulong_t data)
{
        BUG();
}
#endif

void do_syscall_trace(void)
{
        if (!test_thread_flag(TIF_SYSCALL_TRACE))
                return;

        if (!(current->ptrace & PT_PTRACED))
                return;

        /*
         * The 0x80 provides a way for the tracing parent to distinguish
         * between a syscall stop and SIGTRAP delivery
         */
        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;
        }
}

void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code)
{
        struct siginfo info;

        memset(&info, 0, sizeof(info));
        info.si_signo = SIGTRAP;
        info.si_code  = TRAP_BRKPT;
        info.si_addr  = (void __user *) regs->pc;

        /* Send us the fakey SIGTRAP */
        force_sig_info(SIGTRAP, &info, tsk);
}

/* Handle synthetic interrupt delivered only by the simulator. */
void __kprobes do_breakpoint(struct pt_regs* regs, int fault_num)
{
        send_sigtrap(current, regs, fault_num);
}