/*
 * arch/score/kernel/ptrace.c
 *
 * Score Processor version.
 *
 * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
 *  Chen Liqin <liqin.chen@sunplusct.com>
 *  Lennox Wu <lennox.wu@sunplusct.com>
 *
 * 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see the file COPYING, or write
 * to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <linux/elf.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/ptrace.h>
#include <linux/regset.h>

#include <linux/uaccess.h>

/*
 * retrieve the contents of SCORE userspace general registers
 */
static int genregs_get(struct task_struct *target,
                       const struct user_regset *regset,
                       unsigned int pos, unsigned int count,
                       void *kbuf, void __user *ubuf)
{
        const struct pt_regs *regs = task_pt_regs(target);
        int ret;

        /* skip 9 * sizeof(unsigned long) not use for pt_regs */
        ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
                                        0, offsetof(struct pt_regs, regs));

        /* r0 - r31, cel, ceh, sr0, sr1, sr2, epc, ema, psr, ecr, condition */
        ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
                                  regs->regs,
                                  offsetof(struct pt_regs, regs),
                                  offsetof(struct pt_regs, cp0_condition));

        if (!ret)
                ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
                                                sizeof(struct pt_regs), -1);

        return ret;
}

/*
 * update the contents of the SCORE userspace general registers
 */
static int genregs_set(struct task_struct *target,
                       const struct user_regset *regset,
                       unsigned int pos, unsigned int count,
                       const void *kbuf, const void __user *ubuf)
{
        struct pt_regs *regs = task_pt_regs(target);
        int ret;

        /* skip 9 * sizeof(unsigned long) */
        ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
                                        0, offsetof(struct pt_regs, regs));

        /* r0 - r31, cel, ceh, sr0, sr1, sr2, epc, ema, psr, ecr, condition */
        ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                                  regs->regs,
                                  offsetof(struct pt_regs, regs),
                                  offsetof(struct pt_regs, cp0_condition));

        if (!ret)
                ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
                                                sizeof(struct pt_regs), -1);

        return ret;
}

/*
 * Define the register sets available on the score7 under Linux
 */
enum score7_regset {
        REGSET_GENERAL,
};

static const struct user_regset score7_regsets[] = {
        [REGSET_GENERAL] = {
                .core_note_type = NT_PRSTATUS,
                .n              = ELF_NGREG,
                .size           = sizeof(long),
                .align          = sizeof(long),
                .get            = genregs_get,
                .set            = genregs_set,
        },
};

static const struct user_regset_view user_score_native_view = {
        .name           = "score7",
        .e_machine      = EM_SCORE7,
        .regsets        = score7_regsets,
        .n              = ARRAY_SIZE(score7_regsets),
};

const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
        return &user_score_native_view;
}

static int is_16bitinsn(unsigned long insn)
{
        if ((insn & INSN32_MASK) == INSN32_MASK)
                return 0;
        else
                return 1;
}

int
read_tsk_long(struct task_struct *child,
                unsigned long addr, unsigned long *res)
{
        int copied;

        copied = access_process_vm(child, addr, res, sizeof(*res), FOLL_FORCE);

        return copied != sizeof(*res) ? -EIO : 0;
}

int
read_tsk_short(struct task_struct *child,
                unsigned long addr, unsigned short *res)
{
        int copied;

        copied = access_process_vm(child, addr, res, sizeof(*res), FOLL_FORCE);

        return copied != sizeof(*res) ? -EIO : 0;
}

static int
write_tsk_short(struct task_struct *child,
                unsigned long addr, unsigned short val)
{
        int copied;

        copied = access_process_vm(child, addr, &val, sizeof(val),
                        FOLL_FORCE | FOLL_WRITE);

        return copied != sizeof(val) ? -EIO : 0;
}

static int
write_tsk_long(struct task_struct *child,
                unsigned long addr, unsigned long val)
{
        int copied;

        copied = access_process_vm(child, addr, &val, sizeof(val),
                        FOLL_FORCE | FOLL_WRITE);

        return copied != sizeof(val) ? -EIO : 0;
}

void user_enable_single_step(struct task_struct *child)
{
        /* far_epc is the target of branch */
        unsigned int epc, far_epc = 0;
        unsigned long epc_insn, far_epc_insn;
        int ninsn_type;                 /* next insn type 0=16b, 1=32b */
        unsigned int tmp, tmp2;
        struct pt_regs *regs = task_pt_regs(child);
        child->thread.single_step = 1;
        child->thread.ss_nextcnt = 1;
        epc = regs->cp0_epc;

        read_tsk_long(child, epc, &epc_insn);

        if (is_16bitinsn(epc_insn)) {
                if ((epc_insn & J16M) == J16) {
                        tmp = epc_insn & 0xFFE;
                        epc = (epc & 0xFFFFF000) | tmp;
                } else if ((epc_insn & B16M) == B16) {
                        child->thread.ss_nextcnt = 2;
                        tmp = (epc_insn & 0xFF) << 1;
                        tmp = tmp << 23;
                        tmp = (unsigned int)((int) tmp >> 23);
                        far_epc = epc + tmp;
                        epc += 2;
                } else if ((epc_insn & BR16M) == BR16) {
                        child->thread.ss_nextcnt = 2;
                        tmp = (epc_insn >> 4) & 0xF;
                        far_epc = regs->regs[tmp];
                        epc += 2;
                } else
                        epc += 2;
        } else {
                if ((epc_insn & J32M) == J32) {
                        tmp = epc_insn & 0x03FFFFFE;
                        tmp2 = tmp & 0x7FFF;
                        tmp = (((tmp >> 16) & 0x3FF) << 15) | tmp2;
                        epc = (epc & 0xFFC00000) | tmp;
                } else if ((epc_insn & B32M) == B32) {
                        child->thread.ss_nextcnt = 2;
                        tmp = epc_insn & 0x03FFFFFE;    /* discard LK bit */
                        tmp2 = tmp & 0x3FF;
                        tmp = (((tmp >> 16) & 0x3FF) << 10) | tmp2; /* 20bit */
                        tmp = tmp << 12;
                        tmp = (unsigned int)((int) tmp >> 12);
                        far_epc = epc + tmp;
                        epc += 4;
                } else if ((epc_insn & BR32M) == BR32) {
                        child->thread.ss_nextcnt = 2;
                        tmp = (epc_insn >> 16) & 0x1F;
                        far_epc = regs->regs[tmp];
                        epc += 4;
                } else
                        epc += 4;
        }

        if (child->thread.ss_nextcnt == 1) {
                read_tsk_long(child, epc, &epc_insn);

                if (is_16bitinsn(epc_insn)) {
                        write_tsk_short(child, epc, SINGLESTEP16_INSN);
                        ninsn_type = 0;
                } else {
                        write_tsk_long(child, epc, SINGLESTEP32_INSN);
                        ninsn_type = 1;
                }

                if (ninsn_type == 0) {  /* 16bits */
                        child->thread.insn1_type = 0;
                        child->thread.addr1 = epc;
                         /* the insn may have 32bit data */
                        child->thread.insn1 = (short)epc_insn;
                } else {
                        child->thread.insn1_type = 1;
                        child->thread.addr1 = epc;
                        child->thread.insn1 = epc_insn;
                }
        } else {
                /* branch! have two target child->thread.ss_nextcnt=2 */
                read_tsk_long(child, epc, &epc_insn);
                read_tsk_long(child, far_epc, &far_epc_insn);
                if (is_16bitinsn(epc_insn)) {
                        write_tsk_short(child, epc, SINGLESTEP16_INSN);
                        ninsn_type = 0;
                } else {
                        write_tsk_long(child, epc, SINGLESTEP32_INSN);
                        ninsn_type = 1;
                }

                if (ninsn_type == 0) {  /* 16bits */
                        child->thread.insn1_type = 0;
                        child->thread.addr1 = epc;
                         /* the insn may have 32bit data */
                        child->thread.insn1 = (short)epc_insn;
                } else {
                        child->thread.insn1_type = 1;
                        child->thread.addr1 = epc;
                        child->thread.insn1 = epc_insn;
                }

                if (is_16bitinsn(far_epc_insn)) {
                        write_tsk_short(child, far_epc, SINGLESTEP16_INSN);
                        ninsn_type = 0;
                } else {
                        write_tsk_long(child, far_epc, SINGLESTEP32_INSN);
                        ninsn_type = 1;
                }

                if (ninsn_type == 0) {  /* 16bits */
                        child->thread.insn2_type = 0;
                        child->thread.addr2 = far_epc;
                         /* the insn may have 32bit data */
                        child->thread.insn2 = (short)far_epc_insn;
                } else {
                        child->thread.insn2_type = 1;
                        child->thread.addr2 = far_epc;
                        child->thread.insn2 = far_epc_insn;
                }
        }
}

void user_disable_single_step(struct task_struct *child)
{
        if (child->thread.insn1_type == 0)
                write_tsk_short(child, child->thread.addr1,
                                child->thread.insn1);

        if (child->thread.insn1_type == 1)
                write_tsk_long(child, child->thread.addr1,
                                child->thread.insn1);

        if (child->thread.ss_nextcnt == 2) {    /* branch */
                if (child->thread.insn1_type == 0)
                        write_tsk_short(child, child->thread.addr1,
                                        child->thread.insn1);
                if (child->thread.insn1_type == 1)
                        write_tsk_long(child, child->thread.addr1,
                                        child->thread.insn1);
                if (child->thread.insn2_type == 0)
                        write_tsk_short(child, child->thread.addr2,
                                        child->thread.insn2);
                if (child->thread.insn2_type == 1)
                        write_tsk_long(child, child->thread.addr2,
                                        child->thread.insn2);
        }

        child->thread.single_step = 0;
        child->thread.ss_nextcnt = 0;
}

void ptrace_disable(struct task_struct *child)
{
        user_disable_single_step(child);
}

long
arch_ptrace(struct task_struct *child, long request,
            unsigned long addr, unsigned long data)
{
        int ret;
        unsigned long __user *datap = (void __user *)data;

        switch (request) {
        case PTRACE_GETREGS:
                ret = copy_regset_to_user(child, &user_score_native_view,
                                                REGSET_GENERAL,
                                                0, sizeof(struct pt_regs),
                                                datap);
                break;

        case PTRACE_SETREGS:
                ret = copy_regset_from_user(child, &user_score_native_view,
                                                REGSET_GENERAL,
                                                0, sizeof(struct pt_regs),
                                                datap);
                break;

        default:
                ret = ptrace_request(child, request, addr, data);
                break;
        }

        return ret;
}

/*
 * Notification of system call entry/exit
 * - triggered by current->work.syscall_trace
 */
asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit)
{
        if (!(current->ptrace & PT_PTRACED))
                return;

        if (!test_thread_flag(TIF_SYSCALL_TRACE))
                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;
        }
}