arch/m68knommu/kernel/ptrace.c

   1 /*
   2  *  linux/arch/m68knommu/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         PT_REG(d1), PT_REG(d2), PT_REG(d3), PT_REG(d4),
  51         PT_REG(d5), SW_REG(d6), SW_REG(d7), PT_REG(a0),
  52         PT_REG(a1), PT_REG(a2), SW_REG(a3), SW_REG(a4),
  53         SW_REG(a5), SW_REG(a6), PT_REG(d0), -1,
  54         PT_REG(orig_d0), PT_REG(sr), PT_REG(pc),
  55 };
  56
  57 /*
  58  * Get contents of register REGNO in task TASK.
  59  */
  60 static inline long get_reg(struct task_struct *task, int regno)
  61 {
  62         unsigned long *addr;
  63
  64         if (regno == PT_USP)
  65                 addr = &task->thread.usp;
  66         else if (regno < sizeof(regoff)/sizeof(regoff[0]))
  67                 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
  68         else
  69                 return 0;
  70         return *addr;
  71 }
  72
  73 /*
  74  * Write contents of register REGNO in task TASK.
  75  */
  76 static inline int put_reg(struct task_struct *task, int regno,
  77                           unsigned long data)
  78 {
  79         unsigned long *addr;
  80
  81         if (regno == PT_USP)
  82                 addr = &task->thread.usp;
  83         else if (regno < sizeof(regoff)/sizeof(regoff[0]))
  84                 addr = (unsigned long *) (task->thread.esp0 + regoff[regno]);
  85         else
  86                 return -1;
  87         *addr = data;
  88         return 0;
  89 }
  90
  91 /*
  92  * Called by kernel/ptrace.c when detaching..
  93  *
  94  * Make sure the single step bit is not set.
  95  */
  96 void ptrace_disable(struct task_struct *child)
  97 {
  98         unsigned long tmp;
  99         /* make sure the single step bit is not set. */
 100         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 101         put_reg(child, PT_SR, tmp);
 102 }
 103
 104 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
 105 {
 106         struct task_struct *child;
 107         int ret;
 108
 109         lock_kernel();
 110         ret = -EPERM;
 111         if (request == PTRACE_TRACEME) {
 112                 /* are we already being traced? */
 113                 if (current->ptrace & PT_PTRACED)
 114                         goto out;
 115                 /* set the ptrace bit in the process flags. */
 116                 current->ptrace |= PT_PTRACED;
 117                 ret = 0;
 118                 goto out;
 119         }
 120         ret = -ESRCH;
 121         read_lock(&tasklist_lock);
 122         child = find_task_by_pid(pid);
 123         if (child)
 124                 get_task_struct(child);
 125         read_unlock(&tasklist_lock);
 126         if (!child)
 127                 goto out;
 128
 129         ret = -EPERM;
 130         if (pid == 1)           /* you may not mess with init */
 131                 goto out_tsk;
 132
 133         if (request == PTRACE_ATTACH) {
 134                 ret = ptrace_attach(child);
 135                 goto out_tsk;
 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 if (addr == 49) {
 183                                 tmp = child->mm->start_code;
 184                         } else if (addr == 50) {
 185                                 tmp = child->mm->start_data;
 186                         } else if (addr == 51) {
 187                                 tmp = child->mm->end_code;
 188                         } else
 189                                 break;
 190                         ret = put_user(tmp,(unsigned long *) data);
 191                         break;
 192                 }
 193
 194                 /* when I and D space are separate, this will have to be fixed. */
 195                 case PTRACE_POKETEXT: /* write the word at location addr. */
 196                 case PTRACE_POKEDATA:
 197                         ret = 0;
 198                         if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 199                                 break;
 200                         ret = -EIO;
 201                         break;
 202
 203                 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 204                         ret = -EIO;
 205                         if ((addr & 3) || addr < 0 ||
 206                             addr > sizeof(struct user) - 3)
 207                                 break;
 208
 209                         addr = addr >> 2; /* temporary hack. */
 210
 211                         if (addr == PT_SR) {
 212                                 data &= SR_MASK;
 213                                 data <<= 16;
 214                                 data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 215                         }
 216                         if (addr < 19) {
 217                                 if (put_reg(child, addr, data))
 218                                         break;
 219                                 ret = 0;
 220                                 break;
 221                         }
 222                         if (addr >= 21 && addr < 48)
 223                         {
 224 #ifdef CONFIG_M68KFPU_EMU
 225                                 /* Convert long double format
 226                                  * into internal fpu reg representation
 227                                  */
 228                                 if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) {
 229                                         data = (unsigned long)data << 15;
 230                                         data = (data & 0xffff0000) |
 231                                                ((data & 0x0000ffff) >> 1);
 232                                 }
 233 #endif
 234                                 child->thread.fp[addr - 21] = data;
 235                                 ret = 0;
 236                         }
 237                         break;
 238
 239                 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 240                 case PTRACE_CONT: { /* restart after signal. */
 241                         long tmp;
 242
 243                         ret = -EIO;
 244                         if (!valid_signal(data))
 245                                 break;
 246                         if (request == PTRACE_SYSCALL)
 247                                 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 248                         else
 249                                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 250                         child->exit_code = data;
 251                         /* make sure the single step bit is not set. */
 252                         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 253                         put_reg(child, PT_SR, tmp);
 254                         wake_up_process(child);
 255                         ret = 0;
 256                         break;
 257                 }
 258
 259                 /*
 260                  * make the child exit.  Best I can do is send it a sigkill.
 261                  * perhaps it should be put in the status that it wants to
 262                  * exit.
 263                  */
 264                 case PTRACE_KILL: {
 265                         long tmp;
 266
 267                         ret = 0;
 268                         if (child->exit_state == EXIT_ZOMBIE) /* already dead */
 269                                 break;
 270                         child->exit_code = SIGKILL;
 271                         /* make sure the single step bit is not set. */
 272                         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 273                         put_reg(child, PT_SR, tmp);
 274                         wake_up_process(child);
 275                         break;
 276                 }
 277
 278                 case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 279                         long tmp;
 280
 281                         ret = -EIO;
 282                         if (!valid_signal(data))
 283                                 break;
 284                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 285                         tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
 286                         put_reg(child, PT_SR, tmp);
 287
 288                         child->exit_code = data;
 289                         /* give it a chance to run. */
 290                         wake_up_process(child);
 291                         ret = 0;
 292                         break;
 293                 }
 294
 295                 case PTRACE_DETACH:     /* detach a process that was attached. */
 296                         ret = ptrace_detach(child, data);
 297                         break;
 298
 299                 case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 300                         int i;
 301                         unsigned long tmp;
 302                         for (i = 0; i < 19; i++) {
 303                             tmp = get_reg(child, i);
 304                             if (i == PT_SR)
 305                                 tmp >>= 16;
 306                             if (put_user(tmp, (unsigned long *) data)) {
 307                                 ret = -EFAULT;
 308                                 break;
 309                             }
 310                             data += sizeof(long);
 311                         }
 312                         ret = 0;
 313                         break;
 314                 }
 315
 316                 case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 317                         int i;
 318                         unsigned long tmp;
 319                         for (i = 0; i < 19; i++) {
 320                             if (get_user(tmp, (unsigned long *) data)) {
 321                                 ret = -EFAULT;
 322                                 break;
 323                             }
 324                             if (i == PT_SR) {
 325                                 tmp &= SR_MASK;
 326                                 tmp <<= 16;
 327                                 tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 328                             }
 329                             put_reg(child, i, tmp);
 330                             data += sizeof(long);
 331                         }
 332                         ret = 0;
 333                         break;
 334                 }
 335
 336 #ifdef PTRACE_GETFPREGS
 337                 case PTRACE_GETFPREGS: { /* Get the child FPU state. */
 338                         ret = 0;
 339                         if (copy_to_user((void *)data, &child->thread.fp,
 340                                          sizeof(struct user_m68kfp_struct)))
 341                                 ret = -EFAULT;
 342                         break;
 343                 }
 344 #endif
 345
 346 #ifdef PTRACE_SETFPREGS
 347                 case PTRACE_SETFPREGS: { /* Set the child FPU state. */
 348                         ret = 0;
 349                         if (copy_from_user(&child->thread.fp, (void *)data,
 350                                            sizeof(struct user_m68kfp_struct)))
 351                                 ret = -EFAULT;
 352                         break;
 353                 }
 354 #endif
 355
 356                 default:
 357                         ret = -EIO;
 358                         break;
 359         }
 360 out_tsk:
 361         put_task_struct(child);
 362 out:
 363         unlock_kernel();
 364         return ret;
 365 }
 366
 367 asmlinkage void syscall_trace(void)
 368 {
 369         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 370                 return;
 371         if (!(current->ptrace & PT_PTRACED))
 372                 return;
 373         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 374                                  ? 0x80 : 0));
 375         /*
 376          * this isn't the same as continuing with a signal, but it will do
 377          * for normal use.  strace only continues with a signal if the
 378          * stopping signal is not SIGTRAP.  -brl
 379          */
 380         if (current->exit_code) {
 381                 send_sig(current->exit_code, current, 1);
 382                 current->exit_code = 0;
 383         }
 384 }