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ptrace32.c

/*
 * 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/smp_lock.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) + FPRHALF(i)

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);
                  tmp = ((unsigned long int *)child->thread.fpr)
                        [FPRINDEX(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 {
                  flush_fp_to_thread(child);
                  ((unsigned int *)child->thread.regs)[index] = 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;
}

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