arch/frv/kernel/ptrace.c

   1 /* ptrace.c: FRV specific parts of process tracing
   2  *
   3  * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  * - Derived from arch/m68k/kernel/ptrace.c
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version
  10  * 2 of the License, or (at your option) any later version.
  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/errno.h>
  18 #include <linux/ptrace.h>
  19 #include <linux/user.h>
  20 #include <linux/security.h>
  21 #include <linux/signal.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 #include <asm/unistd.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 /*
  36  * Get contents of register REGNO in task TASK.
  37  */
  38 static inline long get_reg(struct task_struct *task, int regno)
  39 {
  40         struct user_context *user = task->thread.user;
  41
  42         if (regno < 0 || regno >= PT__END)
  43                 return 0;
  44
  45         return ((unsigned long *) user)[regno];
  46 }
  47
  48 /*
  49  * Write contents of register REGNO in task TASK.
  50  */
  51 static inline int put_reg(struct task_struct *task, int regno,
  52                           unsigned long data)
  53 {
  54         struct user_context *user = task->thread.user;
  55
  56         if (regno < 0 || regno >= PT__END)
  57                 return -EIO;
  58
  59         switch (regno) {
  60         case PT_GR(0):
  61                 return 0;
  62         case PT_PSR:
  63         case PT__STATUS:
  64                 return -EIO;
  65         default:
  66                 ((unsigned long *) user)[regno] = data;
  67                 return 0;
  68         }
  69 }
  70
  71 /*
  72  * check that an address falls within the bounds of the target process's memory
  73  * mappings
  74  */
  75 static inline int is_user_addr_valid(struct task_struct *child,
  76                                      unsigned long start, unsigned long len)
  77 {
  78 #ifdef CONFIG_MMU
  79         if (start >= PAGE_OFFSET || len > PAGE_OFFSET - start)
  80                 return -EIO;
  81         return 0;
  82 #else
  83         struct vm_area_struct *vma;
  84
  85         vma = find_vma(child->mm, start);
  86         if (vma && start >= vma->vm_start && start + len <= vma->vm_end)
  87                 return 0;
  88
  89         return -EIO;
  90 #endif
  91 }
  92
  93 /*
  94  * Called by kernel/ptrace.c when detaching..
  95  *
  96  * Control h/w single stepping
  97  */
  98 void ptrace_disable(struct task_struct *child)
  99 {
 100         child->thread.frame0->__status &= ~REG__STATUS_STEP;
 101 }
 102
 103 void ptrace_enable(struct task_struct *child)
 104 {
 105         child->thread.frame0->__status |= REG__STATUS_STEP;
 106 }
 107
 108 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 109 {
 110         unsigned long tmp;
 111         int ret;
 112
 113         switch (request) {
 114                 /* when I and D space are separate, these will need to be fixed. */
 115         case PTRACE_PEEKTEXT: /* read word at location addr. */
 116         case PTRACE_PEEKDATA:
 117                 ret = -EIO;
 118                 if (is_user_addr_valid(child, addr, sizeof(tmp)) < 0)
 119                         break;
 120                 ret = generic_ptrace_peekdata(child, addr, data);
 121                 break;
 122
 123                 /* read the word at location addr in the USER area. */
 124         case PTRACE_PEEKUSR: {
 125                 tmp = 0;
 126                 ret = -EIO;
 127                 if ((addr & 3) || addr < 0)
 128                         break;
 129
 130                 ret = 0;
 131                 switch (addr >> 2) {
 132                 case 0 ... PT__END - 1:
 133                         tmp = get_reg(child, addr >> 2);
 134                         break;
 135
 136                 case PT__END + 0:
 137                         tmp = child->mm->end_code - child->mm->start_code;
 138                         break;
 139
 140                 case PT__END + 1:
 141                         tmp = child->mm->end_data - child->mm->start_data;
 142                         break;
 143
 144                 case PT__END + 2:
 145                         tmp = child->mm->start_stack - child->mm->start_brk;
 146                         break;
 147
 148                 case PT__END + 3:
 149                         tmp = child->mm->start_code;
 150                         break;
 151
 152                 case PT__END + 4:
 153                         tmp = child->mm->start_stack;
 154                         break;
 155
 156                 default:
 157                         ret = -EIO;
 158                         break;
 159                 }
 160
 161                 if (ret == 0)
 162                         ret = put_user(tmp, (unsigned long *) data);
 163                 break;
 164         }
 165
 166                 /* when I and D space are separate, this will have to be fixed. */
 167         case PTRACE_POKETEXT: /* write the word at location addr. */
 168         case PTRACE_POKEDATA:
 169                 ret = -EIO;
 170                 if (is_user_addr_valid(child, addr, sizeof(tmp)) < 0)
 171                         break;
 172                 ret = generic_ptrace_pokedata(child, addr, data);
 173                 break;
 174
 175         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 176                 ret = -EIO;
 177                 if ((addr & 3) || addr < 0)
 178                         break;
 179
 180                 ret = 0;
 181                 switch (addr >> 2) {
 182                 case 0 ... PT__END-1:
 183                         ret = put_reg(child, addr >> 2, data);
 184                         break;
 185
 186                 default:
 187                         ret = -EIO;
 188                         break;
 189                 }
 190                 break;
 191
 192         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 193         case PTRACE_CONT: /* restart after signal. */
 194                 ret = -EIO;
 195                 if (!valid_signal(data))
 196                         break;
 197                 if (request == PTRACE_SYSCALL)
 198                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 199                 else
 200                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 201                 child->exit_code = data;
 202                 ptrace_disable(child);
 203                 wake_up_process(child);
 204                 ret = 0;
 205                 break;
 206
 207                 /* make the child exit.  Best I can do is send it a sigkill.
 208                  * perhaps it should be put in the status that it wants to
 209                  * exit.
 210                  */
 211         case PTRACE_KILL:
 212                 ret = 0;
 213                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 214                         break;
 215                 child->exit_code = SIGKILL;
 216                 clear_tsk_thread_flag(child, TIF_SINGLESTEP);
 217                 ptrace_disable(child);
 218                 wake_up_process(child);
 219                 break;
 220
 221         case PTRACE_SINGLESTEP:  /* set the trap flag. */
 222                 ret = -EIO;
 223                 if (!valid_signal(data))
 224                         break;
 225                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 226                 ptrace_enable(child);
 227                 child->exit_code = data;
 228                 wake_up_process(child);
 229                 ret = 0;
 230                 break;
 231
 232         case PTRACE_DETACH:     /* detach a process that was attached. */
 233                 ret = ptrace_detach(child, data);
 234                 break;
 235
 236         case PTRACE_GETREGS: { /* Get all integer regs from the child. */
 237                 int i;
 238                 for (i = 0; i < PT__GPEND; i++) {
 239                         tmp = get_reg(child, i);
 240                         if (put_user(tmp, (unsigned long *) data)) {
 241                                 ret = -EFAULT;
 242                                 break;
 243                         }
 244                         data += sizeof(long);
 245                 }
 246                 ret = 0;
 247                 break;
 248         }
 249
 250         case PTRACE_SETREGS: { /* Set all integer regs in the child. */
 251                 int i;
 252                 for (i = 0; i < PT__GPEND; i++) {
 253                         if (get_user(tmp, (unsigned long *) data)) {
 254                                 ret = -EFAULT;
 255                                 break;
 256                         }
 257                         put_reg(child, i, tmp);
 258                         data += sizeof(long);
 259                 }
 260                 ret = 0;
 261                 break;
 262         }
 263
 264         case PTRACE_GETFPREGS: { /* Get the child FP/Media state. */
 265                 ret = 0;
 266                 if (copy_to_user((void *) data,
 267                                  &child->thread.user->f,
 268                                  sizeof(child->thread.user->f)))
 269                         ret = -EFAULT;
 270                 break;
 271         }
 272
 273         case PTRACE_SETFPREGS: { /* Set the child FP/Media state. */
 274                 ret = 0;
 275                 if (copy_from_user(&child->thread.user->f,
 276                                    (void *) data,
 277                                    sizeof(child->thread.user->f)))
 278                         ret = -EFAULT;
 279                 break;
 280         }
 281
 282         case PTRACE_GETFDPIC:
 283                 tmp = 0;
 284                 switch (addr) {
 285                 case PTRACE_GETFDPIC_EXEC:
 286                         tmp = child->mm->context.exec_fdpic_loadmap;
 287                         break;
 288                 case PTRACE_GETFDPIC_INTERP:
 289                         tmp = child->mm->context.interp_fdpic_loadmap;
 290                         break;
 291                 default:
 292                         break;
 293                 }
 294
 295                 ret = 0;
 296                 if (put_user(tmp, (unsigned long *) data)) {
 297                         ret = -EFAULT;
 298                         break;
 299                 }
 300                 break;
 301
 302         default:
 303                 ret = -EIO;
 304                 break;
 305         }
 306         return ret;
 307 }
 308
 309 asmlinkage void do_syscall_trace(int leaving)
 310 {
 311         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 312                 return;
 313
 314         if (!(current->ptrace & PT_PTRACED))
 315                 return;
 316
 317         /* we need to indicate entry or exit to strace */
 318         if (leaving)
 319                 __frame->__status |= REG__STATUS_SYSC_EXIT;
 320         else
 321                 __frame->__status |= REG__STATUS_SYSC_ENTRY;
 322
 323         ptrace_notify(SIGTRAP);
 324
 325         /*
 326          * this isn't the same as continuing with a signal, but it will do
 327          * for normal use.  strace only continues with a signal if the
 328          * stopping signal is not SIGTRAP.  -brl
 329          */
 330         if (current->exit_code) {
 331                 send_sig(current->exit_code, current, 1);
 332                 current->exit_code = 0;
 333         }
 334 }