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 #include <linux/signal.h>
  23
  24 #include <asm/uaccess.h>
  25 #include <asm/page.h>
  26 #include <asm/pgtable.h>
  27 #include <asm/system.h>
  28 #include <asm/processor.h>
  29
  30 /*
  31  * does not yet catch signals sent when the child dies.
  32  * in exit.c or in signal.c.
  33  */
  34
  35 /* determines which bits in the SR the user has access to. */
  36 /* 1 = access 0 = no access */
  37 #define SR_MASK 0x001f
  38
  39 /* sets the trace bits. */
  40 #define TRACE_BITS 0x8000
  41
  42 /* Find the stack offset for a register, relative to thread.esp0. */
  43 #define PT_REG(reg)     ((long)&((struct pt_regs *)0)->reg)
  44 #define SW_REG(reg)     ((long)&((struct switch_stack *)0)->reg \
  45                          - sizeof(struct switch_stack))
  46 /* Mapping from PT_xxx to the stack offset at which the register is
  47    saved.  Notice that usp has no stack-slot and needs to be treated
  48    specially (see get_reg/put_reg below). */
  49 static int regoff[] = {
  50         [0]     = PT_REG(d1),
  51         [1]     = PT_REG(d2),
  52         [2]     = PT_REG(d3),
  53         [3]     = PT_REG(d4),
  54         [4]     = PT_REG(d5),
  55         [5]     = SW_REG(d6),
  56         [6]     = SW_REG(d7),
  57         [7]     = PT_REG(a0),
  58         [8]     = PT_REG(a1),
  59         [9]     = PT_REG(a2),
  60         [10]    = SW_REG(a3),
  61         [11]    = SW_REG(a4),
  62         [12]    = SW_REG(a5),
  63         [13]    = SW_REG(a6),
  64         [14]    = PT_REG(d0),
  65         [15]    = -1,
  66         [16]    = PT_REG(orig_d0),
  67         [17]    = PT_REG(sr),
  68         [18]    = PT_REG(pc),
  69 };
  70
  71 /*
  72  * Get contents of register REGNO in task TASK.
  73  */
  74 static inline long get_reg(struct task_struct *task, int regno)
  75 {
  76         unsigned long *addr;
  77
  78         if (regno == PT_USP)
  79                 addr = &task->thread.usp;
  80         else if (regno < sizeof(regoff)/sizeof(regoff[0]))
  81                 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
  82         else
  83                 return 0;
  84         return *addr;
  85 }
  86
  87 /*
  88  * Write contents of register REGNO in task TASK.
  89  */
  90 static inline int put_reg(struct task_struct *task, int regno,
  91                           unsigned long data)
  92 {
  93         unsigned long *addr;
  94
  95         if (regno == PT_USP)
  96                 addr = &task->thread.usp;
  97         else if (regno < sizeof(regoff)/sizeof(regoff[0]))
  98                 addr = (unsigned long *) (task->thread.esp0 + regoff[regno]);
  99         else
 100                 return -1;
 101         *addr = data;
 102         return 0;
 103 }
 104
 105 /*
 106  * Called by kernel/ptrace.c when detaching..
 107  *
 108  * Make sure the single step bit is not set.
 109  */
 110 void ptrace_disable(struct task_struct *child)
 111 {
 112         unsigned long tmp;
 113         /* make sure the single step bit is not set. */
 114         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 115         put_reg(child, PT_SR, tmp);
 116         child->thread.work.delayed_trace = 0;
 117         child->thread.work.syscall_trace = 0;
 118 }
 119
 120 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
 121 {
 122         struct task_struct *child;
 123         int ret;
 124
 125         lock_kernel();
 126         ret = -EPERM;
 127         if (request == PTRACE_TRACEME) {
 128                 /* are we already being traced? */
 129                 if (current->ptrace & PT_PTRACED)
 130                         goto out;
 131                 /* set the ptrace bit in the process flags. */
 132                 current->ptrace |= PT_PTRACED;
 133                 ret = 0;
 134                 goto out;
 135         }
 136         ret = -ESRCH;
 137         read_lock(&tasklist_lock);
 138         child = find_task_by_pid(pid);
 139         if (child)
 140                 get_task_struct(child);
 141         read_unlock(&tasklist_lock);
 142         if (!child)
 143                 goto out;
 144
 145         ret = -EPERM;
 146         if (pid == 1)           /* you may not mess with init */
 147                 goto out_tsk;
 148
 149         if (request == PTRACE_ATTACH) {
 150                 ret = ptrace_attach(child);
 151                 goto out_tsk;
 152         }
 153
 154         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 155         if (ret < 0)
 156                 goto out_tsk;
 157
 158         switch (request) {
 159         /* when I and D space are separate, these will need to be fixed. */
 160                 case PTRACE_PEEKTEXT: /* read word at location addr. */
 161                 case PTRACE_PEEKDATA: {
 162                         unsigned long tmp;
 163                         int copied;
 164
 165                         copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 166                         ret = -EIO;
 167                         if (copied != sizeof(tmp))
 168                                 break;
 169                         ret = put_user(tmp,(unsigned long *) data);
 170                         break;
 171                 }
 172
 173         /* read the word at location addr in the USER area. */
 174                 case PTRACE_PEEKUSR: {
 175                         unsigned long tmp;
 176
 177                         ret = -EIO;
 178                         if ((addr & 3) || addr < 0 ||
 179                             addr > sizeof(struct user) - 3)
 180                                 break;
 181
 182                         tmp = 0;  /* Default return condition */
 183                         addr = addr >> 2; /* temporary hack. */
 184                         ret = -EIO;
 185                         if (addr < 19) {
 186                                 tmp = get_reg(child, addr);
 187                                 if (addr == PT_SR)
 188                                         tmp >>= 16;
 189                         } else if (addr >= 21 && addr < 49) {
 190                                 tmp = child->thread.fp[addr - 21];
 191 #ifdef CONFIG_M68KFPU_EMU
 192                                 /* Convert internal fpu reg representation
 193                                  * into long double format
 194                                  */
 195                                 if (FPU_IS_EMU && (addr < 45) && !(addr % 3))
 196                                         tmp = ((tmp & 0xffff0000) << 15) |
 197                                               ((tmp & 0x0000ffff) << 16);
 198 #endif
 199                         } else
 200                                 break;
 201                         ret = put_user(tmp,(unsigned long *) data);
 202                         break;
 203                 }
 204
 205       /* when I and D space are separate, this will have to be fixed. */
 206                 case PTRACE_POKETEXT: /* write the word at location addr. */
 207                 case PTRACE_POKEDATA:
 208                         ret = 0;
 209                         if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 210                                 break;
 211                         ret = -EIO;
 212                         break;
 213
 214                 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 215                         ret = -EIO;
 216                         if ((addr & 3) || addr < 0 ||
 217                             addr > sizeof(struct user) - 3)
 218                                 break;
 219
 220                         addr = addr >> 2; /* temporary hack. */
 221
 222                         if (addr == PT_SR) {
 223                                 data &= SR_MASK;
 224                                 data <<= 16;
 225                                 data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 226                         }
 227                         if (addr < 19) {
 228                                 if (put_reg(child, addr, data))
 229                                         break;
 230                                 ret = 0;
 231                                 break;
 232                         }
 233                         if (addr >= 21 && addr < 48)
 234                         {
 235 #ifdef CONFIG_M68KFPU_EMU
 236                                 /* Convert long double format
 237                                  * into internal fpu reg representation
 238                                  */
 239                                 if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) {
 240                                         data = (unsigned long)data << 15;
 241                                         data = (data & 0xffff0000) |
 242                                                ((data & 0x0000ffff) >> 1);
 243                                 }
 244 #endif
 245                                 child->thread.fp[addr - 21] = data;
 246                                 ret = 0;
 247                         }
 248                         break;
 249
 250                 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 251                 case PTRACE_CONT: { /* restart after signal. */
 252                         long tmp;
 253
 254                         ret = -EIO;
 255                         if (!valid_signal(data))
 256                                 break;
 257                         if (request == PTRACE_SYSCALL) {
 258                                         child->thread.work.syscall_trace = ~0;
 259                         } else {
 260                                         child->thread.work.syscall_trace = 0;
 261                         }
 262                         child->exit_code = data;
 263                         /* make sure the single step bit is not set. */
 264                         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 265                         put_reg(child, PT_SR, tmp);
 266                         child->thread.work.delayed_trace = 0;
 267                         wake_up_process(child);
 268                         ret = 0;
 269                         break;
 270                 }
 271
 272 /*
 273  * make the child exit.  Best I can do is send it a sigkill.
 274  * perhaps it should be put in the status that it wants to
 275  * exit.
 276  */
 277                 case PTRACE_KILL: {
 278                         long tmp;
 279
 280                         ret = 0;
 281                         if (child->exit_state == EXIT_ZOMBIE) /* already dead */
 282                                 break;
 283                         child->exit_code = SIGKILL;
 284         /* make sure the single step bit is not set. */
 285                         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 286                         put_reg(child, PT_SR, tmp);
 287                         child->thread.work.delayed_trace = 0;
 288                         wake_up_process(child);
 289                         break;
 290                 }
 291
 292                 case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 293                         long tmp;
 294
 295                         ret = -EIO;
 296                         if (!valid_signal(data))
 297                                 break;
 298                         child->thread.work.syscall_trace = 0;
 299                         tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
 300                         put_reg(child, PT_SR, tmp);
 301                         child->thread.work.delayed_trace = 1;
 302
 303                         child->exit_code = data;
 304         /* give it a chance to run. */
 305                         wake_up_process(child);
 306                         ret = 0;
 307                         break;
 308                 }
 309
 310                 case PTRACE_DETACH:     /* detach a process that was attached. */
 311                         ret = ptrace_detach(child, data);
 312                         break;
 313
 314                 case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 315                         int i;
 316                         unsigned long tmp;
 317                         for (i = 0; i < 19; i++) {
 318                             tmp = get_reg(child, i);
 319                             if (i == PT_SR)
 320                                 tmp >>= 16;
 321                             if (put_user(tmp, (unsigned long *) data)) {
 322                                 ret = -EFAULT;
 323                                 break;
 324                             }
 325                             data += sizeof(long);
 326                         }
 327                         ret = 0;
 328                         break;
 329                 }
 330
 331                 case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 332                         int i;
 333                         unsigned long tmp;
 334                         for (i = 0; i < 19; i++) {
 335                             if (get_user(tmp, (unsigned long *) data)) {
 336                                 ret = -EFAULT;
 337                                 break;
 338                             }
 339                             if (i == PT_SR) {
 340                                 tmp &= SR_MASK;
 341                                 tmp <<= 16;
 342                                 tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 343                             }
 344                             put_reg(child, i, tmp);
 345                             data += sizeof(long);
 346                         }
 347                         ret = 0;
 348                         break;
 349                 }
 350
 351                 case PTRACE_GETFPREGS: { /* Get the child FPU state. */
 352                         ret = 0;
 353                         if (copy_to_user((void *)data, &child->thread.fp,
 354                                          sizeof(struct user_m68kfp_struct)))
 355                                 ret = -EFAULT;
 356                         break;
 357                 }
 358
 359                 case PTRACE_SETFPREGS: { /* Set the child FPU state. */
 360                         ret = 0;
 361                         if (copy_from_user(&child->thread.fp, (void *)data,
 362                                            sizeof(struct user_m68kfp_struct)))
 363                                 ret = -EFAULT;
 364                         break;
 365                 }
 366
 367                 default:
 368                         ret = ptrace_request(child, request, addr, data);
 369                         break;
 370         }
 371 out_tsk:
 372         put_task_struct(child);
 373 out:
 374         unlock_kernel();
 375         return ret;
 376 }
 377
 378 asmlinkage void syscall_trace(void)
 379 {
 380         if (!current->thread.work.delayed_trace &&
 381             !current->thread.work.syscall_trace)
 382                 return;
 383         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 384                                  ? 0x80 : 0));
 385         /*
 386          * this isn't the same as continuing with a signal, but it will do
 387          * for normal use.  strace only continues with a signal if the
 388          * stopping signal is not SIGTRAP.  -brl
 389          */
 390         if (current->exit_code) {
 391                 send_sig(current->exit_code, current, 1);
 392                 current->exit_code = 0;
 393         }
 394 }