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
  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 /*
  91  * Called by kernel/ptrace.c when detaching..
  92  *
  93  * Make sure the single step bit is not set.
  94  */
  95 void 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
 103 asmlinkage 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         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 137         if (ret < 0)
 138                 goto out_tsk;
 139
 140         switch (request) {
 141                 /* when I and D space are separate, these will need to be fixed. */
 142                 case PTRACE_PEEKTEXT: /* read word at location addr. */
 143                 case PTRACE_PEEKDATA: {
 144                         unsigned long tmp;
 145                         int copied;
 146
 147                         copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 148                         ret = -EIO;
 149                         if (copied != sizeof(tmp))
 150                                 break;
 151                         ret = put_user(tmp,(unsigned long *) data);
 152                         break;
 153                 }
 154
 155                 /* read the word at location addr in the USER area. */
 156                 case PTRACE_PEEKUSR: {
 157                         unsigned long tmp;
 158
 159                         ret = -EIO;
 160                         if ((addr & 3) || addr < 0 ||
 161                             addr > sizeof(struct user) - 3)
 162                                 break;
 163
 164                         tmp = 0;  /* Default return condition */
 165                         addr = addr >> 2; /* temporary hack. */
 166                         ret = -EIO;
 167                         if (addr < 19) {
 168                                 tmp = get_reg(child, addr);
 169                                 if (addr == PT_SR)
 170                                         tmp >>= 16;
 171                         } else if (addr >= 21 && addr < 49) {
 172                                 tmp = child->thread.fp[addr - 21];
 173 #ifdef CONFIG_M68KFPU_EMU
 174                                 /* Convert internal fpu reg representation
 175                                  * into long double format
 176                                  */
 177                                 if (FPU_IS_EMU && (addr < 45) && !(addr % 3))
 178                                         tmp = ((tmp & 0xffff0000) << 15) |
 179                                               ((tmp & 0x0000ffff) << 16);
 180 #endif
 181                         } else if (addr == 49) {
 182                                 tmp = child->mm->start_code;
 183                         } else if (addr == 50) {
 184                                 tmp = child->mm->start_data;
 185                         } else if (addr == 51) {
 186                                 tmp = child->mm->end_code;
 187                         } else
 188                                 break;
 189                         ret = put_user(tmp,(unsigned long *) data);
 190                         break;
 191                 }
 192
 193                 /* when I and D space are separate, this will have to be fixed. */
 194                 case PTRACE_POKETEXT: /* write the word at location addr. */
 195                 case PTRACE_POKEDATA:
 196                         ret = 0;
 197                         if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 198                                 break;
 199                         ret = -EIO;
 200                         break;
 201
 202                 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 203                         ret = -EIO;
 204                         if ((addr & 3) || addr < 0 ||
 205                             addr > sizeof(struct user) - 3)
 206                                 break;
 207
 208                         addr = addr >> 2; /* temporary hack. */
 209
 210                         if (addr == PT_SR) {
 211                                 data &= SR_MASK;
 212                                 data <<= 16;
 213                                 data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 214                         }
 215                         if (addr < 19) {
 216                                 if (put_reg(child, addr, data))
 217                                         break;
 218                                 ret = 0;
 219                                 break;
 220                         }
 221                         if (addr >= 21 && addr < 48)
 222                         {
 223 #ifdef CONFIG_M68KFPU_EMU
 224                                 /* Convert long double format
 225                                  * into internal fpu reg representation
 226                                  */
 227                                 if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) {
 228                                         data = (unsigned long)data << 15;
 229                                         data = (data & 0xffff0000) |
 230                                                ((data & 0x0000ffff) >> 1);
 231                                 }
 232 #endif
 233                                 child->thread.fp[addr - 21] = data;
 234                                 ret = 0;
 235                         }
 236                         break;
 237
 238                 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 239                 case PTRACE_CONT: { /* restart after signal. */
 240                         long tmp;
 241
 242                         ret = -EIO;
 243                         if ((unsigned long) data > _NSIG)
 244                                 break;
 245                         if (request == PTRACE_SYSCALL)
 246                                 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 247                         else
 248                                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 249                         child->exit_code = data;
 250                         /* make sure the single step bit is not set. */
 251                         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 252                         put_reg(child, PT_SR, tmp);
 253                         wake_up_process(child);
 254                         ret = 0;
 255                         break;
 256                 }
 257
 258                 /*
 259                  * make the child exit.  Best I can do is send it a sigkill.
 260                  * perhaps it should be put in the status that it wants to
 261                  * exit.
 262                  */
 263                 case PTRACE_KILL: {
 264                         long tmp;
 265
 266                         ret = 0;
 267                         if (child->exit_state == EXIT_ZOMBIE) /* already dead */
 268                                 break;
 269                         child->exit_code = SIGKILL;
 270                         /* make sure the single step bit is not set. */
 271                         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 272                         put_reg(child, PT_SR, tmp);
 273                         wake_up_process(child);
 274                         break;
 275                 }
 276
 277                 case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 278                         long tmp;
 279
 280                         ret = -EIO;
 281                         if ((unsigned long) data > _NSIG)
 282                                 break;
 283                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 284                         tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
 285                         put_reg(child, PT_SR, tmp);
 286
 287                         child->exit_code = data;
 288                         /* give it a chance to run. */
 289                         wake_up_process(child);
 290                         ret = 0;
 291                         break;
 292                 }
 293
 294                 case PTRACE_DETACH:     /* detach a process that was attached. */
 295                         ret = ptrace_detach(child, data);
 296                         break;
 297
 298                 case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 299                         int i;
 300                         unsigned long tmp;
 301                         for (i = 0; i < 19; i++) {
 302                             tmp = get_reg(child, i);
 303                             if (i == PT_SR)
 304                                 tmp >>= 16;
 305                             if (put_user(tmp, (unsigned long *) data)) {
 306                                 ret = -EFAULT;
 307                                 break;
 308                             }
 309                             data += sizeof(long);
 310                         }
 311                         ret = 0;
 312                         break;
 313                 }
 314
 315                 case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 316                         int i;
 317                         unsigned long tmp;
 318                         for (i = 0; i < 19; i++) {
 319                             if (get_user(tmp, (unsigned long *) data)) {
 320                                 ret = -EFAULT;
 321                                 break;
 322                             }
 323                             if (i == PT_SR) {
 324                                 tmp &= SR_MASK;
 325                                 tmp <<= 16;
 326                                 tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 327                             }
 328                             put_reg(child, i, tmp);
 329                             data += sizeof(long);
 330                         }
 331                         ret = 0;
 332                         break;
 333                 }
 334
 335 #ifdef PTRACE_GETFPREGS
 336                 case PTRACE_GETFPREGS: { /* Get the child FPU state. */
 337                         ret = 0;
 338                         if (copy_to_user((void *)data, &child->thread.fp,
 339                                          sizeof(struct user_m68kfp_struct)))
 340                                 ret = -EFAULT;
 341                         break;
 342                 }
 343 #endif
 344
 345 #ifdef PTRACE_SETFPREGS
 346                 case PTRACE_SETFPREGS: { /* Set the child FPU state. */
 347                         ret = 0;
 348                         if (copy_from_user(&child->thread.fp, (void *)data,
 349                                            sizeof(struct user_m68kfp_struct)))
 350                                 ret = -EFAULT;
 351                         break;
 352                 }
 353 #endif
 354
 355                 default:
 356                         ret = -EIO;
 357                         break;
 358         }
 359 out_tsk:
 360         put_task_struct(child);
 361 out:
 362         unlock_kernel();
 363         return ret;
 364 }
 365
 366 asmlinkage void syscall_trace(void)
 367 {
 368         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 369                 return;
 370         if (!(current->ptrace & PT_PTRACED))
 371                 return;
 372         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 373                                  ? 0x80 : 0));
 374         /*
 375          * this isn't the same as continuing with a signal, but it will do
 376          * for normal use.  strace only continues with a signal if the
 377          * stopping signal is not SIGTRAP.  -brl
 378          */
 379         if (current->exit_code) {
 380                 send_sig(current->exit_code, current, 1);
 381                 current->exit_code = 0;
 382         }
 383 }