ptrace32.c

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/*
 * ptrace for 32-bit processes running on a 64-bit kernel.
 *
 *  PowerPC version
 *    Copyright (C) 1995-1996 Gary Thomas ([email protected])
 *
 *  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 ([email protected])
 * and Paul Mackerras ([email protected]).
 *
 * 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/switch_to.h>

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

/* 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;
#ifdef CONFIG_PPC_ADV_DEBUG_REGS
        ret = put_user(child->thread.dac1, (u32 __user *)data);
#else
        ret = put_user(child->thread.dabr, (u32 __user *)data);
#endif
        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 PTRACE_KILL:
    case PTRACE_SINGLESTEP:
    case PTRACE_DETACH:
    case PTRACE_SET_DEBUGREG:
    case PTRACE_SYSCALL:
    case PTRACE_CONT:
    case PPC_PTRACE_GETHWDBGINFO:
    case PPC_PTRACE_SETHWDEBUG:
    case PPC_PTRACE_DELHWDEBUG:
        ret = arch_ptrace(child, request, addr, data);
        break;

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

    return ret;
}