LXR linux-old/arch/m68k/kernel/ptrace.c

   1/*
   2 *  linux/arch/m68k/kernel/ptrace.c
   3 *
   4 *  Copyright (C) 1994 by Hamish Macdonald
   5 *  Taken from linux/kernel/ptrace.c and modified for M680x0.
   6 *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
   7 *
   8 * This file is subject to the terms and conditions of the GNU General
   9 * Public License.  See the file COPYING in the main directory of
  10 * this archive for more details.
  11 */
  12
  13#include <linux/kernel.h>
  14#include <linux/sched.h>
  15#include <linux/mm.h>
  16#include <linux/smp.h>
  17#include <linux/smp_lock.h>
  18#include <linux/errno.h>
  19#include <linux/ptrace.h>
  20#include <linux/user.h>
  21#include <linux/config.h>
  22
  23#include <asm/uaccess.h>
  24#include <asm/page.h>
  25#include <asm/pgtable.h>
  26#include <asm/system.h>
  27#include <asm/processor.h>
  28
  29/*
  30 * does not yet catch signals sent when the child dies.
  31 * in exit.c or in signal.c.
  32 */
  33
  34/* determines which bits in the SR the user has access to. */
  35/* 1 = access 0 = no access */
  36#define SR_MASK 0x001f
  37
  38/* sets the trace bits. */
  39#define TRACE_BITS 0x8000
  40
  41/* Find the stack offset for a register, relative to thread.esp0. */
  42#define PT_REG(reg)     ((long)&((struct pt_regs *)0)->reg)
  43#define SW_REG(reg)     ((long)&((struct switch_stack *)0)->reg \
  44                         - sizeof(struct switch_stack))
  45/* Mapping from PT_xxx to the stack offset at which the register is
  46   saved.  Notice that usp has no stack-slot and needs to be treated
  47   specially (see get_reg/put_reg below). */
  48static int regoff[] = {
  49        PT_REG(d1), PT_REG(d2), PT_REG(d3), PT_REG(d4),
  50        PT_REG(d5), SW_REG(d6), SW_REG(d7), PT_REG(a0),
  51        PT_REG(a1), PT_REG(a2), SW_REG(a3), SW_REG(a4),
  52        SW_REG(a5), SW_REG(a6), PT_REG(d0), -1,
  53        PT_REG(orig_d0), PT_REG(sr), PT_REG(pc),
  54};
  55
  56/*
  57 * Get contents of register REGNO in task TASK.
  58 */
  59static inline long get_reg(struct task_struct *task, int regno)
  60{
  61        unsigned long *addr;
  62
  63        if (regno == PT_USP)
  64                addr = &task->thread.usp;
  65        else if (regno < sizeof(regoff)/sizeof(regoff[0]))
  66                addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
  67        else
  68                return 0;
  69        return *addr;
  70}
  71
  72/*
  73 * Write contents of register REGNO in task TASK.
  74 */
  75static inline int put_reg(struct task_struct *task, int regno,
  76                          unsigned long data)
  77{
  78        unsigned long *addr;
  79
  80        if (regno == PT_USP)
  81                addr = &task->thread.usp;
  82        else if (regno < sizeof(regoff)/sizeof(regoff[0]))
  83                addr = (unsigned long *) (task->thread.esp0 + regoff[regno]);
  84        else
  85                return -1;
  86        *addr = data;
  87        return 0;
  88}
  89
  90/*
  91 * Called by kernel/ptrace.c when detaching..
  92 *
  93 * Make sure the single step bit is not set.
  94 */
  95void ptrace_disable(struct task_struct *child)
  96{
  97        unsigned long tmp;
  98        /* make sure the single step bit is not set. */
  99        tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 100        put_reg(child, PT_SR, tmp);
 101}
 102
 103asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
 104{
 105        struct task_struct *child;
 106        int ret;
 107
 108        lock_kernel();
 109        ret = -EPERM;
 110        if (request == PTRACE_TRACEME) {
 111                /* are we already being traced? */
 112                if (current->ptrace & PT_PTRACED)
 113                        goto out;
 114                /* set the ptrace bit in the process flags. */
 115                current->ptrace |= PT_PTRACED;
 116                ret = 0;
 117                goto out;
 118        }
 119        ret = -ESRCH;
 120        read_lock(&tasklist_lock);
 121        child = find_task_by_pid(pid);
 122        if (child)
 123                get_task_struct(child);
 124        read_unlock(&tasklist_lock);
 125        if (!child)
 126                goto out;
 127
 128        ret = -EPERM;
 129        if (pid == 1)           /* you may not mess with init */
 130                goto out_tsk;
 131
 132        if (request == PTRACE_ATTACH) {
 133                ret = ptrace_attach(child);
 134                goto out_tsk;
 135        }
 136
 137        ret = ptrace_check_attach(child, request == PTRACE_KILL);
 138        if (ret < 0)
 139                goto out_tsk;
 140
 141        switch (request) {
 142        /* when I and D space are separate, these will need to be fixed. */
 143                case PTRACE_PEEKTEXT: /* read word at location addr. */ 
 144                case PTRACE_PEEKDATA: {
 145                        unsigned long tmp;
 146                        int copied;
 147
 148                        copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 149                        ret = -EIO;
 150                        if (copied != sizeof(tmp))
 151                                break;
 152                        ret = put_user(tmp,(unsigned long *) data);
 153                        break;
 154                }
 155
 156        /* read the word at location addr in the USER area. */
 157                case PTRACE_PEEKUSR: {
 158                        unsigned long tmp;
 159                        
 160                        ret = -EIO;
 161                        if ((addr & 3) || addr < 0 ||
 162                            addr > sizeof(struct user) - 3)
 163                                break;
 164                        
 165                        tmp = 0;  /* Default return condition */
 166                        addr = addr >> 2; /* temporary hack. */
 167                        ret = -EIO;
 168                        if (addr < 19) {
 169                                tmp = get_reg(child, addr);
 170                                if (addr == PT_SR)
 171                                        tmp >>= 16;
 172                        } else if (addr >= 21 && addr < 49) {
 173                                tmp = child->thread.fp[addr - 21];
 174#ifdef CONFIG_M68KFPU_EMU
 175                                /* Convert internal fpu reg representation
 176                                 * into long double format
 177                                 */
 178                                if (FPU_IS_EMU && (addr < 45) && !(addr % 3))
 179                                        tmp = ((tmp & 0xffff0000) << 15) |
 180                                              ((tmp & 0x0000ffff) << 16);
 181#endif
 182                        } else
 183                                break;
 184                        ret = put_user(tmp,(unsigned long *) data);
 185                        break;
 186                }
 187
 188      /* when I and D space are separate, this will have to be fixed. */
 189                case PTRACE_POKETEXT: /* write the word at location addr. */
 190                case PTRACE_POKEDATA:
 191                        ret = 0;
 192                        if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 193                                break;
 194                        ret = -EIO;
 195                        break;
 196
 197                case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 198                        ret = -EIO;
 199                        if ((addr & 3) || addr < 0 ||
 200                            addr > sizeof(struct user) - 3)
 201                                break;
 202
 203                        addr = addr >> 2; /* temporary hack. */
 204                            
 205                        if (addr == PT_SR) {
 206                                data &= SR_MASK;
 207                                data <<= 16;
 208                                data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 209                        }
 210                        if (addr < 19) {
 211                                if (put_reg(child, addr, data))
 212                                        break;
 213                                ret = 0;
 214                                break;
 215                        }
 216                        if (addr >= 21 && addr < 48)
 217                        {
 218#ifdef CONFIG_M68KFPU_EMU
 219                                /* Convert long double format
 220                                 * into internal fpu reg representation
 221                                 */
 222                                if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) {
 223                                        data = (unsigned long)data << 15;
 224                                        data = (data & 0xffff0000) |
 225                                               ((data & 0x0000ffff) >> 1);
 226                                }
 227#endif
 228                                child->thread.fp[addr - 21] = data;
 229                                ret = 0;
 230                        }
 231                        break;
 232
 233                case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 234                case PTRACE_CONT: { /* restart after signal. */
 235                        long tmp;
 236
 237                        ret = -EIO;
 238                        if ((unsigned long) data > _NSIG)
 239                                break;
 240                        if (request == PTRACE_SYSCALL)
 241                                child->ptrace |= PT_TRACESYS;
 242                        else
 243                                child->ptrace &= ~PT_TRACESYS;
 244                        child->exit_code = data;
 245                        /* make sure the single step bit is not set. */
 246                        tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 247                        put_reg(child, PT_SR, tmp);
 248                        wake_up_process(child);
 249                        ret = 0;
 250                        break;
 251                }
 252
 253/*
 254 * make the child exit.  Best I can do is send it a sigkill. 
 255 * perhaps it should be put in the status that it wants to 
 256 * exit.
 257 */
 258                case PTRACE_KILL: {
 259                        long tmp;
 260
 261                        ret = 0;
 262                        if (child->state == TASK_ZOMBIE) /* already dead */
 263                                break;
 264                        child->exit_code = SIGKILL;
 265        /* make sure the single step bit is not set. */
 266                        tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 267                        put_reg(child, PT_SR, tmp);
 268                        wake_up_process(child);
 269                        break;
 270                }
 271
 272                case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 273                        long tmp;
 274
 275                        ret = -EIO;
 276                        if ((unsigned long) data > _NSIG)
 277                                break;
 278                        child->ptrace &= ~PT_TRACESYS;
 279                        tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
 280                        put_reg(child, PT_SR, tmp);
 281
 282                        child->exit_code = data;
 283        /* give it a chance to run. */
 284                        wake_up_process(child);
 285                        ret = 0;
 286                        break;
 287                }
 288
 289                case PTRACE_DETACH:     /* detach a process that was attached. */
 290                        ret = ptrace_detach(child, data);
 291                        break;
 292
 293                case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 294                        int i;
 295                        unsigned long tmp;
 296                        for (i = 0; i < 19; i++) {
 297                            tmp = get_reg(child, i);
 298                            if (i == PT_SR)
 299                                tmp >>= 16;
 300                            if (put_user(tmp, (unsigned long *) data)) {
 301                                ret = -EFAULT;
 302                                break;
 303                            }
 304                            data += sizeof(long);
 305                        }
 306                        ret = 0;
 307                        break;
 308                }
 309
 310                case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 311                        int i;
 312                        unsigned long tmp;
 313                        for (i = 0; i < 19; i++) {
 314                            if (get_user(tmp, (unsigned long *) data)) {
 315                                ret = -EFAULT;
 316                                break;
 317                            }
 318                            if (i == PT_SR) {
 319                                tmp &= SR_MASK;
 320                                tmp <<= 16;
 321                                tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 322                            }
 323                            put_reg(child, i, tmp);
 324                            data += sizeof(long);
 325                        }
 326                        ret = 0;
 327                        break;
 328                }
 329
 330                case PTRACE_GETFPREGS: { /* Get the child FPU state. */
 331                        ret = 0;
 332                        if (copy_to_user((void *)data, &child->thread.fp,
 333                                         sizeof(struct user_m68kfp_struct)))
 334                                ret = -EFAULT;
 335                        break;
 336                }
 337
 338                case PTRACE_SETFPREGS: { /* Set the child FPU state. */
 339                        ret = 0;
 340                        if (copy_from_user(&child->thread.fp, (void *)data,
 341                                           sizeof(struct user_m68kfp_struct)))
 342                                ret = -EFAULT;
 343                        break;
 344                }
 345
 346                default:
 347                        ret = -EIO;
 348                        break;
 349        }
 350out_tsk:
 351        free_task_struct(child);
 352out:
 353        unlock_kernel();
 354        return ret;
 355}
 356
 357asmlinkage void syscall_trace(void)
 358{
 359        if ((current->ptrace & (PT_PTRACED|PT_TRACESYS))
 360                        != (PT_PTRACED|PT_TRACESYS))
 361                return;
 362        current->exit_code = SIGTRAP;
 363        current->state = TASK_STOPPED;
 364        notify_parent(current, SIGCHLD);
 365        schedule();
 366        /*
 367         * this isn't the same as continuing with a signal, but it will do
 368         * for normal use.  strace only continues with a signal if the
 369         * stopping signal is not SIGTRAP.  -brl
 370         */
 371        if (current->exit_code) {
 372                send_sig(current->exit_code, current, 1);
 373                current->exit_code = 0;
 374        }
 375}
 376