/*
 * ptrace for 32-bit processes running on a 64-bit kernel.
 *
 *  PowerPC version
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 *  Derived from "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
 *
 * Modified by Cort Dougan (cort@hq.fsmlabs.com)
 * and Paul Mackerras (paulus@samba.org).
 *
 * 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/regset.h>
#include <linux/user.h>
#include <linux/security.h>
#include <linux/signal.h>
#include <linux/compat.h>

#include <asm/uaccess.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/system.h>

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

/*
 * Here are the old "legacy" powerpc specific getregs/setregs ptrace calls,
 * we mark them as obsolete now, they will be removed in a future version
 */
static long compat_ptrace_old(struct task_struct *child, long request,
                              long addr, long data)
{
        switch (request) {
        case PPC_PTRACE_GETREGS:        /* Get GPRs 0 - 31. */
                return copy_regset_to_user(child,
                                           task_user_regset_view(current), 0,
                                           0, 32 * sizeof(compat_long_t),
                                           compat_ptr(data));

        case PPC_PTRACE_SETREGS:        /* Set GPRs 0 - 31. */
                return copy_regset_from_user(child,
                                             task_user_regset_view(current), 0,
                                             0, 32 * sizeof(compat_long_t),
                                             compat_ptr(data));
        }

        return -EPERM;
}

/* Macros to workout the correct index for the FPR in the thread struct */
#define FPRNUMBER(i) (((i) - PT_FPR0) >> 1)
#define FPRHALF(i) (((i) - PT_FPR0) & 1)
#define FPRINDEX(i) TS_FPRWIDTH * FPRNUMBER(i) * 2 + FPRHALF(i)
#define FPRINDEX_3264(i) (TS_FPRWIDTH * ((i) - PT_FPR0))

long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
                        compat_ulong_t caddr, compat_ulong_t cdata)
{
        unsigned long addr = caddr;
        unsigned long data = cdata;
        int ret;

        switch (request) {
        /*
         * Read 4 bytes of the other process' storage
         *  data is a pointer specifying where the user wants the
         *      4 bytes copied into
         *  addr is a pointer in the user's storage that contains an 8 byte
         *      address in the other process of the 4 bytes that is to be read
         * (this is run in a 32-bit process looking at a 64-bit process)
         * when I and D space are separate, these will need to be fixed.
         */
        case PPC_PTRACE_PEEKTEXT_3264:
        case PPC_PTRACE_PEEKDATA_3264: {
                u32 tmp;
                int copied;
                u32 __user * addrOthers;

                ret = -EIO;

                /* Get the addr in the other process that we want to read */
                if (get_user(addrOthers, (u32 __user * __user *)addr) != 0)
                        break;

                copied = access_process_vm(child, (u64)addrOthers, &tmp,
                                sizeof(tmp), 0);
                if (copied != sizeof(tmp))
                        break;
                ret = put_user(tmp, (u32 __user *)data);
                break;
        }

        /* Read a register (specified by ADDR) out of the "user area" */
        case PTRACE_PEEKUSR: {
                int index;
                unsigned long tmp;

                ret = -EIO;
                /* convert to index and check */
                index = (unsigned long) addr >> 2;
                if ((addr & 3) || (index > PT_FPSCR32))
                        break;

                CHECK_FULL_REGS(child->thread.regs);
                if (index < PT_FPR0) {
                        tmp = ptrace_get_reg(child, index);
                } else {
                        flush_fp_to_thread(child);
                        /*
                         * the user space code considers the floating point
                         * to be an array of unsigned int (32 bits) - the
                         * index passed in is based on this assumption.
                         */
                        tmp = ((unsigned int *)child->thread.fpr)
                                [FPRINDEX(index)];
                }
                ret = put_user((unsigned int)tmp, (u32 __user *)data);
                break;
        }
  
        /*
         * Read 4 bytes out of the other process' pt_regs area
         *  data is a pointer specifying where the user wants the
         *      4 bytes copied into
         *  addr is the offset into the other process' pt_regs structure
         *      that is to be read
         * (this is run in a 32-bit process looking at a 64-bit process)
         */
        case PPC_PTRACE_PEEKUSR_3264: {
                u32 index;
                u32 reg32bits;
                u64 tmp;
                u32 numReg;
                u32 part;

                ret = -EIO;
                /* Determine which register the user wants */
                index = (u64)addr >> 2;
                numReg = index / 2;
                /* Determine which part of the register the user wants */
                if (index % 2)
                        part = 1;  /* want the 2nd half of the register (right-most). */
                else
                        part = 0;  /* want the 1st half of the register (left-most). */

                /* Validate the input - check to see if address is on the wrong boundary
                 * or beyond the end of the user area
                 */
                if ((addr & 3) || numReg > PT_FPSCR)
                        break;

                CHECK_FULL_REGS(child->thread.regs);
                if (numReg >= PT_FPR0) {
                        flush_fp_to_thread(child);
                        /* get 64 bit FPR */
                        tmp = ((u64 *)child->thread.fpr)
                                [FPRINDEX_3264(numReg)];
                } else { /* register within PT_REGS struct */
                        tmp = ptrace_get_reg(child, numReg);
                } 
                reg32bits = ((u32*)&tmp)[part];
                ret = put_user(reg32bits, (u32 __user *)data);
                break;
        }

        /*
         * Write 4 bytes into the other process' storage
         *  data is the 4 bytes that the user wants written
         *  addr is a pointer in the user's storage that contains an
         *      8 byte address in the other process where the 4 bytes
         *      that is to be written
         * (this is run in a 32-bit process looking at a 64-bit process)
         * when I and D space are separate, these will need to be fixed.
         */
        case PPC_PTRACE_POKETEXT_3264:
        case PPC_PTRACE_POKEDATA_3264: {
                u32 tmp = data;
                u32 __user * addrOthers;

                /* Get the addr in the other process that we want to write into */
                ret = -EIO;
                if (get_user(addrOthers, (u32 __user * __user *)addr) != 0)
                        break;
                ret = 0;
                if (access_process_vm(child, (u64)addrOthers, &tmp,
                                        sizeof(tmp), 1) == sizeof(tmp))
                        break;
                ret = -EIO;
                break;
        }

        /* write the word at location addr in the USER area */
        case PTRACE_POKEUSR: {
                unsigned long index;

                ret = -EIO;
                /* convert to index and check */
                index = (unsigned long) addr >> 2;
                if ((addr & 3) || (index > PT_FPSCR32))
                        break;

                CHECK_FULL_REGS(child->thread.regs);
                if (index < PT_FPR0) {
                        ret = ptrace_put_reg(child, index, data);
                } else {
                        flush_fp_to_thread(child);
                        /*
                         * the user space code considers the floating point
                         * to be an array of unsigned int (32 bits) - the
                         * index passed in is based on this assumption.
                         */
                        ((unsigned int *)child->thread.fpr)
                                [FPRINDEX(index)] = data;
                        ret = 0;
                }
                break;
        }

        /*
         * Write 4 bytes into the other process' pt_regs area
         *  data is the 4 bytes that the user wants written
         *  addr is the offset into the other process' pt_regs structure
         *      that is to be written into
         * (this is run in a 32-bit process looking at a 64-bit process)
         */
        case PPC_PTRACE_POKEUSR_3264: {
                u32 index;
                u32 numReg;

                ret = -EIO;
                /* Determine which register the user wants */
                index = (u64)addr >> 2;
                numReg = index / 2;

                /*
                 * Validate the input - check to see if address is on the
                 * wrong boundary or beyond the end of the user area
                 */
                if ((addr & 3) || (numReg > PT_FPSCR))
                        break;
                CHECK_FULL_REGS(child->thread.regs);
                if (numReg < PT_FPR0) {
                        unsigned long freg = ptrace_get_reg(child, numReg);
                        if (index % 2)
                                freg = (freg & ~0xfffffffful) | (data & 0xfffffffful);
                        else
                                freg = (freg & 0xfffffffful) | (data << 32);
                        ret = ptrace_put_reg(child, numReg, freg);
                } else {
                        u64 *tmp;
                        flush_fp_to_thread(child);
                        /* get 64 bit FPR ... */
                        tmp = &(((u64 *)child->thread.fpr)
                                [FPRINDEX_3264(numReg)]);
                        /* ... write the 32 bit part we want */
                        ((u32 *)tmp)[index % 2] = data;
                        ret = 0;
                }
                break;
        }

        case PTRACE_GET_DEBUGREG: {
                ret = -EINVAL;
                /* We only support one DABR and no IABRS at the moment */
                if (addr > 0)
                        break;
                ret = put_user(child->thread.dabr, (u32 __user *)data);
                break;
        }

        case PTRACE_GETREGS:    /* Get all pt_regs from the child. */
                return copy_regset_to_user(
                        child, task_user_regset_view(current), 0,
                        0, PT_REGS_COUNT * sizeof(compat_long_t),
                        compat_ptr(data));

        case PTRACE_SETREGS:    /* Set all gp regs in the child. */
                return copy_regset_from_user(
                        child, task_user_regset_view(current), 0,
                        0, PT_REGS_COUNT * sizeof(compat_long_t),
                        compat_ptr(data));

        case PTRACE_GETFPREGS:
        case PTRACE_SETFPREGS:
        case PTRACE_GETVRREGS:
        case PTRACE_SETVRREGS:
        case PTRACE_GETVSRREGS:
        case PTRACE_SETVSRREGS:
        case PTRACE_GETREGS64:
        case PTRACE_SETREGS64:
        case PPC_PTRACE_GETFPREGS:
        case PPC_PTRACE_SETFPREGS:
        case PTRACE_KILL:
        case PTRACE_SINGLESTEP:
        case PTRACE_DETACH:
        case PTRACE_SET_DEBUGREG:
        case PTRACE_SYSCALL:
        case PTRACE_CONT:
                ret = arch_ptrace(child, request, addr, data);
                break;

        /* Old reverse args ptrace callss */
        case PPC_PTRACE_GETREGS: /* Get GPRs 0 - 31. */
        case PPC_PTRACE_SETREGS: /* Set GPRs 0 - 31. */
                ret = compat_ptrace_old(child, request, addr, data);
                break;

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

        return ret;
}