/* ptrace.c: FRV specific parts of process tracing
 *
 * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 * - Derived from arch/m68k/kernel/ptrace.c
 *
 * 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.
 */

#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/security.h>
#include <linux/signal.h>
#include <linux/regset.h>
#include <linux/elf.h>
#include <linux/tracehook.h>

#include <asm/uaccess.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
#include <asm/unistd.h>

/*
 * does not yet catch signals sent when the child dies.
 * in exit.c or in signal.c.
 */

/*
 * retrieve the contents of FRV 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 user_int_regs *iregs = &target->thread.user->i;
        int ret;

        ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
                                  iregs, 0, sizeof(*iregs));
        if (ret < 0)
                return ret;

        return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
                                        sizeof(*iregs), -1);
}

/*
 * update the contents of the FRV 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 user_int_regs *iregs = &target->thread.user->i;
        unsigned int offs_gr0, offs_gr1;
        int ret;

        /* not allowed to set PSR or __status */
        if (pos < offsetof(struct user_int_regs, psr) + sizeof(long) &&
            pos + count > offsetof(struct user_int_regs, psr))
                return -EIO;

        if (pos < offsetof(struct user_int_regs, __status) + sizeof(long) &&
            pos + count > offsetof(struct user_int_regs, __status))
                return -EIO;

        /* set the control regs */
        offs_gr0 = offsetof(struct user_int_regs, gr[0]);
        offs_gr1 = offsetof(struct user_int_regs, gr[1]);
        ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                                 iregs, 0, offs_gr0);
        if (ret < 0)
                return ret;

        /* skip GR0/TBR */
        ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
                                        offs_gr0, offs_gr1);
        if (ret < 0)
                return ret;

        /* set the general regs */
        ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                                 &iregs->gr[1], offs_gr1, sizeof(*iregs));
        if (ret < 0)
                return ret;

        return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
                                        sizeof(*iregs), -1);
}

/*
 * retrieve the contents of FRV userspace FP/Media registers
 */
static int fpmregs_get(struct task_struct *target,
                       const struct user_regset *regset,
                       unsigned int pos, unsigned int count,
                       void *kbuf, void __user *ubuf)
{
        const struct user_fpmedia_regs *fpregs = &target->thread.user->f;
        int ret;

        ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
                                  fpregs, 0, sizeof(*fpregs));
        if (ret < 0)
                return ret;

        return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
                                        sizeof(*fpregs), -1);
}

/*
 * update the contents of the FRV userspace FP/Media registers
 */
static int fpmregs_set(struct task_struct *target,
                       const struct user_regset *regset,
                       unsigned int pos, unsigned int count,
                       const void *kbuf, const void __user *ubuf)
{
        struct user_fpmedia_regs *fpregs = &target->thread.user->f;
        int ret;

        ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                                 fpregs, 0, sizeof(*fpregs));
        if (ret < 0)
                return ret;

        return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
                                        sizeof(*fpregs), -1);
}

/*
 * determine if the FP/Media registers have actually been used
 */
static int fpmregs_active(struct task_struct *target,
                          const struct user_regset *regset)
{
        return tsk_used_math(target) ? regset->n : 0;
}

/*
 * Define the register sets available on the FRV under Linux
 */
enum frv_regset {
        REGSET_GENERAL,
        REGSET_FPMEDIA,
};

static const struct user_regset frv_regsets[] = {
        /*
         * General register format is:
         *      PSR, ISR, CCR, CCCR, LR, LCR, PC, (STATUS), SYSCALLNO, ORIG_G8
         *      GNER0-1, IACC0, TBR, GR1-63
         */
        [REGSET_GENERAL] = {
                .core_note_type = NT_PRSTATUS,
                .n              = ELF_NGREG,
                .size           = sizeof(long),
                .align          = sizeof(long),
                .get            = genregs_get,
                .set            = genregs_set,
        },
        /*
         * FPU/Media register format is:
         *      FR0-63, FNER0-1, MSR0-1, ACC0-7, ACCG0-8, FSR
         */
        [REGSET_FPMEDIA] = {
                .core_note_type = NT_PRFPREG,
                .n              = sizeof(struct user_fpmedia_regs) / sizeof(long),
                .size           = sizeof(long),
                .align          = sizeof(long),
                .get            = fpmregs_get,
                .set            = fpmregs_set,
                .active         = fpmregs_active,
        },
};

static const struct user_regset_view user_frv_native_view = {
        .name           = "frv",
        .e_machine      = EM_FRV,
        .regsets        = frv_regsets,
        .n              = ARRAY_SIZE(frv_regsets),
};

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

/*
 * Get contents of register REGNO in task TASK.
 */
static inline long get_reg(struct task_struct *task, int regno)
{
        struct user_context *user = task->thread.user;

        if (regno < 0 || regno >= PT__END)
                return 0;

        return ((unsigned long *) user)[regno];
}

/*
 * Write contents of register REGNO in task TASK.
 */
static inline int put_reg(struct task_struct *task, int regno,
                          unsigned long data)
{
        struct user_context *user = task->thread.user;

        if (regno < 0 || regno >= PT__END)
                return -EIO;

        switch (regno) {
        case PT_GR(0):
                return 0;
        case PT_PSR:
        case PT__STATUS:
                return -EIO;
        default:
                ((unsigned long *) user)[regno] = data;
                return 0;
        }
}

/*
 * Called by kernel/ptrace.c when detaching..
 *
 * Control h/w single stepping
 */
void user_enable_single_step(struct task_struct *child)
{
        child->thread.frame0->__status |= REG__STATUS_STEP;
}

void user_disable_single_step(struct task_struct *child)
{
        child->thread.frame0->__status &= ~REG__STATUS_STEP;
}

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)
{
        unsigned long tmp;
        int ret;
        int regno = addr >> 2;
        unsigned long __user *datap = (unsigned long __user *) data;

        switch (request) {
                /* read the word at location addr in the USER area. */
        case PTRACE_PEEKUSR: {
                tmp = 0;
                ret = -EIO;
                if (addr & 3)
                        break;

                ret = 0;
                switch (regno) {
                case 0 ... PT__END - 1:
                        tmp = get_reg(child, regno);
                        break;

                case PT__END + 0:
                        tmp = child->mm->end_code - child->mm->start_code;
                        break;

                case PT__END + 1:
                        tmp = child->mm->end_data - child->mm->start_data;
                        break;

                case PT__END + 2:
                        tmp = child->mm->start_stack - child->mm->start_brk;
                        break;

                case PT__END + 3:
                        tmp = child->mm->start_code;
                        break;

                case PT__END + 4:
                        tmp = child->mm->start_stack;
                        break;

                default:
                        ret = -EIO;
                        break;
                }

                if (ret == 0)
                        ret = put_user(tmp, datap);
                break;
        }

        case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
                ret = -EIO;
                if (addr & 3)
                        break;

                switch (regno) {
                case 0 ... PT__END - 1:
                        ret = put_reg(child, regno, data);
                        break;
                }
                break;

        case PTRACE_GETREGS:    /* Get all integer regs from the child. */
                return copy_regset_to_user(child, &user_frv_native_view,
                                           REGSET_GENERAL,
                                           0, sizeof(child->thread.user->i),
                                           datap);

        case PTRACE_SETREGS:    /* Set all integer regs in the child. */
                return copy_regset_from_user(child, &user_frv_native_view,
                                             REGSET_GENERAL,
                                             0, sizeof(child->thread.user->i),
                                             datap);

        case PTRACE_GETFPREGS:  /* Get the child FP/Media state. */
                return copy_regset_to_user(child, &user_frv_native_view,
                                           REGSET_FPMEDIA,
                                           0, sizeof(child->thread.user->f),
                                           datap);

        case PTRACE_SETFPREGS:  /* Set the child FP/Media state. */
                return copy_regset_from_user(child, &user_frv_native_view,
                                             REGSET_FPMEDIA,
                                             0, sizeof(child->thread.user->f),
                                             datap);

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

/*
 * handle tracing of system call entry
 * - return the revised system call number or ULONG_MAX to cause ENOSYS
 */
asmlinkage unsigned long syscall_trace_entry(void)
{
        __frame->__status |= REG__STATUS_SYSC_ENTRY;
        if (tracehook_report_syscall_entry(__frame)) {
                /* tracing decided this syscall should not happen, so
                 * We'll return a bogus call number to get an ENOSYS
                 * error, but leave the original number in
                 * __frame->syscallno
                 */
                return ULONG_MAX;
        }

        return __frame->syscallno;
}

/*
 * handle tracing of system call exit
 */
asmlinkage void syscall_trace_exit(void)
{
        __frame->__status |= REG__STATUS_SYSC_EXIT;
        tracehook_report_syscall_exit(__frame, 0);
}