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         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  */
  59 static 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  */
  75 static 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 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
  91 {
  92         struct task_struct *child;
  93         unsigned long flags;
  94         int ret;
  95
  96         lock_kernel();
  97         ret = -EPERM;
  98         if (request == PTRACE_TRACEME) {
  99                 /* are we already being traced? */
 100                 if (current->ptrace & PT_PTRACED)
 101                         goto out;
 102                 /* set the ptrace bit in the process flags. */
 103                 current->ptrace |= PT_PTRACED;
 104                 ret = 0;
 105                 goto out;
 106         }
 107         ret = -ESRCH;
 108         read_lock(&tasklist_lock);
 109         child = find_task_by_pid(pid);
 110         read_unlock(&tasklist_lock);    /* FIXME!!! */
 111         if (!child)
 112                 goto out;
 113         ret = -EPERM;
 114         if (pid == 1)           /* you may not mess with init */
 115                 goto out;
 116         if (request == PTRACE_ATTACH) {
 117                 if (child == current)
 118                         goto out;
 119                 if ((!child->dumpable ||
 120                     (current->uid != child->euid) ||
 121                     (current->uid != child->suid) ||
 122                     (current->uid != child->uid) ||
 123                     (current->gid != child->egid) ||
 124                     (current->gid != child->sgid) ||
 125                     (!cap_issubset(child->cap_permitted, current->cap_permitted)) ||
 126                     (current->gid != child->gid)) && !capable(CAP_SYS_PTRACE))
 127                         goto out;
 128                 /* the same process cannot be attached many times */
 129                 if (child->ptrace & PT_PTRACED)
 130                         goto out;
 131                 child->ptrace |= PT_PTRACED;
 132
 133                 write_lock_irqsave(&tasklist_lock, flags);
 134                 if (child->p_pptr != current) {
 135                         REMOVE_LINKS(child);
 136                         child->p_pptr = current;
 137                         SET_LINKS(child);
 138                 }
 139                 write_unlock_irqrestore(&tasklist_lock, flags);
 140
 141                 send_sig(SIGSTOP, child, 1);
 142                 ret = 0;
 143                 goto out;
 144         }
 145         ret = -ESRCH;
 146         if (!(child->ptrace & PT_PTRACED))
 147                 goto out;
 148         if (child->state != TASK_STOPPED) {
 149                 if (request != PTRACE_KILL)
 150                         goto out;
 151         }
 152         if (child->p_pptr != current)
 153                 goto out;
 154
 155         switch (request) {
 156         /* when I and D space are separate, these will need to be fixed. */
 157                 case PTRACE_PEEKTEXT: /* read word at location addr. */
 158                 case PTRACE_PEEKDATA: {
 159                         unsigned long tmp;
 160                         int copied;
 161
 162                         copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 163                         ret = -EIO;
 164                         if (copied != sizeof(tmp))
 165                                 goto out;
 166                         ret = put_user(tmp,(unsigned long *) data);
 167                         goto out;
 168                 }
 169
 170         /* read the word at location addr in the USER area. */
 171                 case PTRACE_PEEKUSR: {
 172                         unsigned long tmp;
 173
 174                         ret = -EIO;
 175                         if ((addr & 3) || addr < 0 || addr >= sizeof(struct user))
 176                                 goto out;
 177
 178                         tmp = 0;  /* Default return condition */
 179                         addr = addr >> 2; /* temporary hack. */
 180                         ret = -EIO;
 181                         if (addr < 19) {
 182                                 tmp = get_reg(child, addr);
 183                                 if (addr == PT_SR)
 184                                         tmp >>= 16;
 185                         } else if (addr >= 21 && addr < 49) {
 186                                 tmp = child->thread.fp[addr - 21];
 187 #ifdef CONFIG_M68KFPU_EMU
 188                                 /* Convert internal fpu reg representation
 189                                  * into long double format
 190                                  */
 191                                 if (FPU_IS_EMU && (addr < 45) && !(addr % 3))
 192                                         tmp = ((tmp & 0xffff0000) << 15) |
 193                                               ((tmp & 0x0000ffff) << 16);
 194 #endif
 195                         } else
 196                                 goto out;
 197                         ret = put_user(tmp,(unsigned long *) data);
 198                         goto out;
 199                 }
 200
 201       /* when I and D space are separate, this will have to be fixed. */
 202                 case PTRACE_POKETEXT: /* write the word at location addr. */
 203                 case PTRACE_POKEDATA:
 204                         ret = 0;
 205                         if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 206                                 goto out;
 207                         ret = -EIO;
 208                         goto out;
 209
 210                 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 211                         ret = -EIO;
 212                         if ((addr & 3) || addr < 0 || addr >= sizeof(struct user))
 213                                 goto out;
 214
 215                         addr = addr >> 2; /* temporary hack. */
 216
 217                         if (addr == PT_SR) {
 218                                 data &= SR_MASK;
 219                                 data <<= 16;
 220                                 data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 221                         }
 222                         if (addr < 19) {
 223                                 if (put_reg(child, addr, data))
 224                                         goto out;
 225                                 ret = 0;
 226                                 goto out;
 227                         }
 228                         if (addr >= 21 && addr < 48)
 229                         {
 230 #ifdef CONFIG_M68KFPU_EMU
 231                                 /* Convert long double format
 232                                  * into internal fpu reg representation
 233                                  */
 234                                 if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) {
 235                                         data = (unsigned long)data << 15;
 236                                         data = (data & 0xffff0000) |
 237                                                ((data & 0x0000ffff) >> 1);
 238                                 }
 239 #endif
 240                                 child->thread.fp[addr - 21] = data;
 241                                 ret = 0;
 242                         }
 243                         goto out;
 244
 245                 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 246                 case PTRACE_CONT: { /* restart after signal. */
 247                         long tmp;
 248
 249                         ret = -EIO;
 250                         if ((unsigned long) data > _NSIG)
 251                                 goto out;
 252                         if (request == PTRACE_SYSCALL)
 253                                 child->ptrace |= PT_TRACESYS;
 254                         else
 255                                 child->ptrace &= ~PT_TRACESYS;
 256                         child->exit_code = data;
 257                         /* make sure the single step bit is not set. */
 258                         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 259                         put_reg(child, PT_SR, tmp);
 260                         wake_up_process(child);
 261                         ret = 0;
 262                         goto out;
 263                 }
 264
 265 /*
 266  * make the child exit.  Best I can do is send it a sigkill.
 267  * perhaps it should be put in the status that it wants to
 268  * exit.
 269  */
 270                 case PTRACE_KILL: {
 271                         long tmp;
 272
 273                         ret = 0;
 274                         if (child->state == TASK_ZOMBIE) /* already dead */
 275                                 goto out;
 276                         child->exit_code = SIGKILL;
 277         /* make sure the single step bit is not set. */
 278                         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 279                         put_reg(child, PT_SR, tmp);
 280                         wake_up_process(child);
 281                         goto out;
 282                 }
 283
 284                 case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 285                         long tmp;
 286
 287                         ret = -EIO;
 288                         if ((unsigned long) data > _NSIG)
 289                                 goto out;
 290                         child->ptrace &= ~PT_TRACESYS;
 291                         tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
 292                         put_reg(child, PT_SR, tmp);
 293
 294                         child->exit_code = data;
 295         /* give it a chance to run. */
 296                         wake_up_process(child);
 297                         ret = 0;
 298                         goto out;
 299                 }
 300
 301                 case PTRACE_DETACH: { /* detach a process that was attached. */
 302                         long tmp;
 303
 304                         ret = -EIO;
 305                         if ((unsigned long) data > _NSIG)
 306                                 goto out;
 307                         child->ptrace &= ~(PT_PTRACED|PT_TRACESYS);
 308                         child->exit_code = data;
 309                         write_lock_irqsave(&tasklist_lock, flags);
 310                         REMOVE_LINKS(child);
 311                         child->p_pptr = child->p_opptr;
 312                         SET_LINKS(child);
 313                         write_unlock_irqrestore(&tasklist_lock, flags);
 314                         /* make sure the single step bit is not set. */
 315                         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 316                         put_reg(child, PT_SR, tmp);
 317                         wake_up_process(child);
 318                         ret = 0;
 319                         goto out;
 320                 }
 321
 322                 case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 323                         int i;
 324                         unsigned long tmp;
 325                         for (i = 0; i < 19; i++) {
 326                             tmp = get_reg(child, i);
 327                             if (i == PT_SR)
 328                                 tmp >>= 16;
 329                             if (put_user(tmp, (unsigned long *) data)) {
 330                                 ret = -EFAULT;
 331                                 goto out;
 332                             }
 333                             data += sizeof(long);
 334                         }
 335                         ret = 0;
 336                         goto out;
 337                 }
 338
 339                 case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 340                         int i;
 341                         unsigned long tmp;
 342                         for (i = 0; i < 19; i++) {
 343                             if (get_user(tmp, (unsigned long *) data)) {
 344                                 ret = -EFAULT;
 345                                 goto out;
 346                             }
 347                             if (i == PT_SR) {
 348                                 tmp &= SR_MASK;
 349                                 tmp <<= 16;
 350                                 tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 351                             }
 352                             put_reg(child, i, tmp);
 353                             data += sizeof(long);
 354                         }
 355                         ret = 0;
 356                         goto out;
 357                 }
 358
 359                 case PTRACE_GETFPREGS: { /* Get the child FPU state. */
 360                         ret = 0;
 361                         if (copy_to_user((void *)data, &child->thread.fp,
 362                                          sizeof(struct user_m68kfp_struct)))
 363                                 ret = -EFAULT;
 364                         goto out;
 365                 }
 366
 367                 case PTRACE_SETFPREGS: { /* Set the child FPU state. */
 368                         ret = 0;
 369                         if (copy_from_user(&child->thread.fp, (void *)data,
 370                                            sizeof(struct user_m68kfp_struct)))
 371                                 ret = -EFAULT;
 372                         goto out;
 373                 }
 374
 375                 default:
 376                         ret = -EIO;
 377                         goto out;
 378         }
 379 out:
 380         unlock_kernel();
 381         return ret;
 382 }
 383
 384 asmlinkage void syscall_trace(void)
 385 {
 386         lock_kernel();
 387         if ((current->ptrace & (PT_PTRACED|PT_TRACESYS))
 388                         != (PT_PTRACED|PT_TRACESYS))
 389                 goto out;
 390         current->exit_code = SIGTRAP;
 391         current->state = TASK_STOPPED;
 392         notify_parent(current, SIGCHLD);
 393         schedule();
 394         /*
 395          * this isn't the same as continuing with a signal, but it will do
 396          * for normal use.  strace only continues with a signal if the
 397          * stopping signal is not SIGTRAP.  -brl
 398          */
 399         if (current->exit_code) {
 400                 send_sig(current->exit_code, current, 1);
 401                 current->exit_code = 0;
 402         }
 403 out:
 404         unlock_kernel();
 405 }