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). */
  48 static int regoff[] = {
  49         [0]     = PT_REG(d1),
  50         [1]     = PT_REG(d2),
  51         [2]     = PT_REG(d3),
  52         [3]     = PT_REG(d4),
  53         [4]     = PT_REG(d5),
  54         [5]     = SW_REG(d6),
  55         [6]     = SW_REG(d7),
  56         [7]     = PT_REG(a0),
  57         [8]     = PT_REG(a1),
  58         [9]     = PT_REG(a2),
  59         [10]    = SW_REG(a3),
  60         [11]    = SW_REG(a4),
  61         [12]    = SW_REG(a5),
  62         [13]    = SW_REG(a6),
  63         [14]    = PT_REG(d0),
  64         [15]    = -1,
  65         [16]    = PT_REG(orig_d0),
  66         [17]    = PT_REG(sr),
  67         [18]    = PT_REG(pc),
  68 };
  69
  70 /*
  71  * Get contents of register REGNO in task TASK.
  72  */
  73 static inline long get_reg(struct task_struct *task, int regno)
  74 {
  75         unsigned long *addr;
  76
  77         if (regno == PT_USP)
  78                 addr = &task->thread.usp;
  79         else if (regno < sizeof(regoff)/sizeof(regoff[0]))
  80                 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
  81         else
  82                 return 0;
  83         return *addr;
  84 }
  85
  86 /*
  87  * Write contents of register REGNO in task TASK.
  88  */
  89 static inline int put_reg(struct task_struct *task, int regno,
  90                           unsigned long data)
  91 {
  92         unsigned long *addr;
  93
  94         if (regno == PT_USP)
  95                 addr = &task->thread.usp;
  96         else if (regno < sizeof(regoff)/sizeof(regoff[0]))
  97                 addr = (unsigned long *) (task->thread.esp0 + regoff[regno]);
  98         else
  99                 return -1;
 100         *addr = data;
 101         return 0;
 102 }
 103
 104 /*
 105  * Called by kernel/ptrace.c when detaching..
 106  *
 107  * Make sure the single step bit is not set.
 108  */
 109 void ptrace_disable(struct task_struct *child)
 110 {
 111         unsigned long tmp;
 112         /* make sure the single step bit is not set. */
 113         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 114         put_reg(child, PT_SR, tmp);
 115         child->thread.work.delayed_trace = 0;
 116         child->thread.work.syscall_trace = 0;
 117 }
 118
 119 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
 120 {
 121         struct task_struct *child;
 122         int ret;
 123
 124         lock_kernel();
 125         ret = -EPERM;
 126         if (request == PTRACE_TRACEME) {
 127                 /* are we already being traced? */
 128                 if (current->ptrace & PT_PTRACED)
 129                         goto out;
 130                 /* set the ptrace bit in the process flags. */
 131                 current->ptrace |= PT_PTRACED;
 132                 ret = 0;
 133                 goto out;
 134         }
 135         ret = -ESRCH;
 136         read_lock(&tasklist_lock);
 137         child = find_task_by_pid(pid);
 138         if (child)
 139                 get_task_struct(child);
 140         read_unlock(&tasklist_lock);
 141         if (!child)
 142                 goto out;
 143
 144         ret = -EPERM;
 145         if (pid == 1)           /* you may not mess with init */
 146                 goto out_tsk;
 147
 148         if (request == PTRACE_ATTACH) {
 149                 ret = ptrace_attach(child);
 150                 goto out_tsk;
 151         }
 152
 153         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 154         if (ret < 0)
 155                 goto out_tsk;
 156
 157         switch (request) {
 158         /* when I and D space are separate, these will need to be fixed. */
 159                 case PTRACE_PEEKTEXT: /* read word at location addr. */
 160                 case PTRACE_PEEKDATA: {
 161                         unsigned long tmp;
 162                         int copied;
 163
 164                         copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 165                         ret = -EIO;
 166                         if (copied != sizeof(tmp))
 167                                 break;
 168                         ret = put_user(tmp,(unsigned long *) data);
 169                         break;
 170                 }
 171
 172         /* read the word at location addr in the USER area. */
 173                 case PTRACE_PEEKUSR: {
 174                         unsigned long tmp;
 175
 176                         ret = -EIO;
 177                         if ((addr & 3) || addr < 0 ||
 178                             addr > sizeof(struct user) - 3)
 179                                 break;
 180
 181                         tmp = 0;  /* Default return condition */
 182                         addr = addr >> 2; /* temporary hack. */
 183                         ret = -EIO;
 184                         if (addr < 19) {
 185                                 tmp = get_reg(child, addr);
 186                                 if (addr == PT_SR)
 187                                         tmp >>= 16;
 188                         } else if (addr >= 21 && addr < 49) {
 189                                 tmp = child->thread.fp[addr - 21];
 190 #ifdef CONFIG_M68KFPU_EMU
 191                                 /* Convert internal fpu reg representation
 192                                  * into long double format
 193                                  */
 194                                 if (FPU_IS_EMU && (addr < 45) && !(addr % 3))
 195                                         tmp = ((tmp & 0xffff0000) << 15) |
 196                                               ((tmp & 0x0000ffff) << 16);
 197 #endif
 198                         } else
 199                                 break;
 200                         ret = put_user(tmp,(unsigned long *) data);
 201                         break;
 202                 }
 203
 204       /* when I and D space are separate, this will have to be fixed. */
 205                 case PTRACE_POKETEXT: /* write the word at location addr. */
 206                 case PTRACE_POKEDATA:
 207                         ret = 0;
 208                         if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 209                                 break;
 210                         ret = -EIO;
 211                         break;
 212
 213                 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 214                         ret = -EIO;
 215                         if ((addr & 3) || addr < 0 ||
 216                             addr > sizeof(struct user) - 3)
 217                                 break;
 218
 219                         addr = addr >> 2; /* temporary hack. */
 220
 221                         if (addr == PT_SR) {
 222                                 data &= SR_MASK;
 223                                 data <<= 16;
 224                                 data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 225                         }
 226                         if (addr < 19) {
 227                                 if (put_reg(child, addr, data))
 228                                         break;
 229                                 ret = 0;
 230                                 break;
 231                         }
 232                         if (addr >= 21 && addr < 48)
 233                         {
 234 #ifdef CONFIG_M68KFPU_EMU
 235                                 /* Convert long double format
 236                                  * into internal fpu reg representation
 237                                  */
 238                                 if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) {
 239                                         data = (unsigned long)data << 15;
 240                                         data = (data & 0xffff0000) |
 241                                                ((data & 0x0000ffff) >> 1);
 242                                 }
 243 #endif
 244                                 child->thread.fp[addr - 21] = data;
 245                                 ret = 0;
 246                         }
 247                         break;
 248
 249                 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 250                 case PTRACE_CONT: { /* restart after signal. */
 251                         long tmp;
 252
 253                         ret = -EIO;
 254                         if ((unsigned long) data > _NSIG)
 255                                 break;
 256                         if (request == PTRACE_SYSCALL) {
 257                                         child->thread.work.syscall_trace = ~0;
 258                         } else {
 259                                         child->thread.work.syscall_trace = 0;
 260                         }
 261                         child->exit_code = data;
 262                         /* make sure the single step bit is not set. */
 263                         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 264                         put_reg(child, PT_SR, tmp);
 265                         child->thread.work.delayed_trace = 0;
 266                         wake_up_process(child);
 267                         ret = 0;
 268                         break;
 269                 }
 270
 271 /*
 272  * make the child exit.  Best I can do is send it a sigkill.
 273  * perhaps it should be put in the status that it wants to
 274  * exit.
 275  */
 276                 case PTRACE_KILL: {
 277                         long tmp;
 278
 279                         ret = 0;
 280                         if (child->state == TASK_ZOMBIE) /* already dead */
 281                                 break;
 282                         child->exit_code = SIGKILL;
 283         /* make sure the single step bit is not set. */
 284                         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 285                         put_reg(child, PT_SR, tmp);
 286                         child->thread.work.delayed_trace = 0;
 287                         wake_up_process(child);
 288                         break;
 289                 }
 290
 291                 case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 292                         long tmp;
 293
 294                         ret = -EIO;
 295                         if ((unsigned long) data > _NSIG)
 296                                 break;
 297                         child->thread.work.syscall_trace = 0;
 298                         tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
 299                         put_reg(child, PT_SR, tmp);
 300                         child->thread.work.delayed_trace = 1;
 301
 302                         child->exit_code = data;
 303         /* give it a chance to run. */
 304                         wake_up_process(child);
 305                         ret = 0;
 306                         break;
 307                 }
 308
 309                 case PTRACE_DETACH:     /* detach a process that was attached. */
 310                         ret = ptrace_detach(child, data);
 311                         break;
 312
 313                 case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 314                         int i;
 315                         unsigned long tmp;
 316                         for (i = 0; i < 19; i++) {
 317                             tmp = get_reg(child, i);
 318                             if (i == PT_SR)
 319                                 tmp >>= 16;
 320                             if (put_user(tmp, (unsigned long *) data)) {
 321                                 ret = -EFAULT;
 322                                 break;
 323                             }
 324                             data += sizeof(long);
 325                         }
 326                         ret = 0;
 327                         break;
 328                 }
 329
 330                 case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 331                         int i;
 332                         unsigned long tmp;
 333                         for (i = 0; i < 19; i++) {
 334                             if (get_user(tmp, (unsigned long *) data)) {
 335                                 ret = -EFAULT;
 336                                 break;
 337                             }
 338                             if (i == PT_SR) {
 339                                 tmp &= SR_MASK;
 340                                 tmp <<= 16;
 341                                 tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 342                             }
 343                             put_reg(child, i, tmp);
 344                             data += sizeof(long);
 345                         }
 346                         ret = 0;
 347                         break;
 348                 }
 349
 350                 case PTRACE_GETFPREGS: { /* Get the child FPU state. */
 351                         ret = 0;
 352                         if (copy_to_user((void *)data, &child->thread.fp,
 353                                          sizeof(struct user_m68kfp_struct)))
 354                                 ret = -EFAULT;
 355                         break;
 356                 }
 357
 358                 case PTRACE_SETFPREGS: { /* Set the child FPU state. */
 359                         ret = 0;
 360                         if (copy_from_user(&child->thread.fp, (void *)data,
 361                                            sizeof(struct user_m68kfp_struct)))
 362                                 ret = -EFAULT;
 363                         break;
 364                 }
 365
 366                 default:
 367                         ret = ptrace_request(child, request, addr, data);
 368                         break;
 369         }
 370 out_tsk:
 371         put_task_struct(child);
 372 out:
 373         unlock_kernel();
 374         return ret;
 375 }
 376
 377 asmlinkage void syscall_trace(void)
 378 {
 379         if (!current->thread.work.delayed_trace &&
 380             !current->thread.work.syscall_trace)
 381                 return;
 382         current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 383                                         ? 0x80 : 0);
 384         current->state = TASK_STOPPED;
 385         notify_parent(current, SIGCHLD);
 386         schedule();
 387         /*
 388          * this isn't the same as continuing with a signal, but it will do
 389          * for normal use.  strace only continues with a signal if the
 390          * stopping signal is not SIGTRAP.  -brl
 391          */
 392         if (current->exit_code) {
 393                 send_sig(current->exit_code, current, 1);
 394                 current->exit_code = 0;
 395         }
 396 }