arch/xtensa/kernel/ptrace.c

   1 // TODO some minor issues
   2 /*
   3  * This file is subject to the terms and conditions of the GNU General Public
   4  * License.  See the file "COPYING" in the main directory of this archive
   5  * for more details.
   6  *
   7  * Copyright (C) 2001 - 2005  Tensilica Inc.
   8  *
   9  * Joe Taylor   <joe@tensilica.com, joetylr@yahoo.com>
  10  * Chris Zankel <chris@zankel.net>
  11  * Scott Foehner<sfoehner@yahoo.com>,
  12  * Kevin Chea
  13  * Marc Gauthier<marc@tensilica.com> <marc@alumni.uwaterloo.ca>
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/sched.h>
  18 #include <linux/mm.h>
  19 #include <linux/errno.h>
  20 #include <linux/ptrace.h>
  21 #include <linux/smp.h>
  22 #include <linux/smp_lock.h>
  23 #include <linux/security.h>
  24 #include <linux/signal.h>
  25
  26 #include <asm/pgtable.h>
  27 #include <asm/page.h>
  28 #include <asm/system.h>
  29 #include <asm/uaccess.h>
  30 #include <asm/ptrace.h>
  31 #include <asm/elf.h>
  32
  33 #define TEST_KERNEL     // verify kernel operations FIXME: remove
  34
  35
  36 /*
  37  * Called by kernel/ptrace.c when detaching..
  38  *
  39  * Make sure single step bits etc are not set.
  40  */
  41
  42 void ptrace_disable(struct task_struct *child)
  43 {
  44         /* Nothing to do.. */
  45 }
  46
  47 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
  48 {
  49         int ret = -EPERM;
  50
  51         switch (request) {
  52         case PTRACE_PEEKTEXT: /* read word at location addr. */
  53         case PTRACE_PEEKDATA:
  54         {
  55                 unsigned long tmp;
  56                 int copied;
  57
  58                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
  59                 ret = -EIO;
  60                 if (copied != sizeof(tmp))
  61                         break;
  62                 ret = put_user(tmp,(unsigned long *) data);
  63
  64                 goto out;
  65         }
  66
  67         /* Read the word at location addr in the USER area.  */
  68
  69         case PTRACE_PEEKUSR:
  70                 {
  71                 struct pt_regs *regs;
  72                 unsigned long tmp;
  73
  74                 regs = task_pt_regs(child);
  75                 tmp = 0;  /* Default return value. */
  76
  77                 switch(addr) {
  78
  79                 case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
  80                         {
  81                         int ar = addr - REG_AR_BASE - regs->windowbase * 4;
  82                         ar &= (XCHAL_NUM_AREGS - 1);
  83                         if (ar < 16 && ar + (regs->wmask >> 4) * 4 >= 0)
  84                                 tmp = regs->areg[ar];
  85                         else
  86                                 ret = -EIO;
  87                         break;
  88                         }
  89                 case REG_A_BASE ... REG_A_BASE + 15:
  90                         tmp = regs->areg[addr - REG_A_BASE];
  91                         break;
  92                 case REG_PC:
  93                         tmp = regs->pc;
  94                         break;
  95                 case REG_PS:
  96                         /* Note:  PS.EXCM is not set while user task is running;
  97                          * its being set in regs is for exception handling
  98                          * convenience.  */
  99                         tmp = (regs->ps & ~XCHAL_PS_EXCM_MASK);
 100                         break;
 101                 case REG_WB:
 102                         tmp = regs->windowbase;
 103                         break;
 104                 case REG_WS:
 105                         tmp = regs->windowstart;
 106                         break;
 107                 case REG_LBEG:
 108                         tmp = regs->lbeg;
 109                         break;
 110                 case REG_LEND:
 111                         tmp = regs->lend;
 112                         break;
 113                 case REG_LCOUNT:
 114                         tmp = regs->lcount;
 115                         break;
 116                 case REG_SAR:
 117                         tmp = regs->sar;
 118                         break;
 119                 case REG_DEPC:
 120                         tmp = regs->depc;
 121                         break;
 122                 case REG_EXCCAUSE:
 123                         tmp = regs->exccause;
 124                         break;
 125                 case REG_EXCVADDR:
 126                         tmp = regs->excvaddr;
 127                         break;
 128                 case SYSCALL_NR:
 129                         tmp = regs->syscall;
 130                         break;
 131                 default:
 132                         tmp = 0;
 133                         ret = -EIO;
 134                         goto out;
 135                 }
 136                 ret = put_user(tmp, (unsigned long *) data);
 137                 goto out;
 138                 }
 139
 140         case PTRACE_POKETEXT: /* write the word at location addr. */
 141         case PTRACE_POKEDATA:
 142                 if (access_process_vm(child, addr, &data, sizeof(data), 1)
 143                     == sizeof(data))
 144                         break;
 145                 ret = -EIO;
 146                 goto out;
 147
 148         case PTRACE_POKEUSR:
 149                 {
 150                 struct pt_regs *regs;
 151                 regs = task_pt_regs(child);
 152
 153                 switch (addr) {
 154                 case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
 155                         {
 156                         int ar = addr - REG_AR_BASE - regs->windowbase * 4;
 157                         if (ar < 16 && ar + (regs->wmask >> 4) * 4 >= 0)
 158                                 regs->areg[ar & (XCHAL_NUM_AREGS - 1)] = data;
 159                         else
 160                                 ret = -EIO;
 161                         break;
 162                         }
 163                 case REG_A_BASE ... REG_A_BASE + 15:
 164                         regs->areg[addr - REG_A_BASE] = data;
 165                         break;
 166                 case REG_PC:
 167                         regs->pc = data;
 168                         break;
 169                 case SYSCALL_NR:
 170                         regs->syscall = data;
 171                         break;
 172 #ifdef TEST_KERNEL
 173                 case REG_WB:
 174                         regs->windowbase = data;
 175                         break;
 176                 case REG_WS:
 177                         regs->windowstart = data;
 178                         break;
 179 #endif
 180
 181                 default:
 182                         /* The rest are not allowed. */
 183                         ret = -EIO;
 184                         break;
 185                 }
 186                 break;
 187                 }
 188
 189         /* continue and stop at next (return from) syscall */
 190         case PTRACE_SYSCALL:
 191         case PTRACE_CONT: /* restart after signal. */
 192         {
 193                 ret = -EIO;
 194                 if (!valid_signal(data))
 195                         break;
 196                 if (request == PTRACE_SYSCALL)
 197                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 198                 else
 199                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 200                 child->exit_code = data;
 201                 /* Make sure the single step bit is not set. */
 202                 child->ptrace &= ~PT_SINGLESTEP;
 203                 wake_up_process(child);
 204                 ret = 0;
 205                 break;
 206         }
 207
 208         /*
 209          * make the child exit.  Best I can do is send it a sigkill.
 210          * perhaps it should be put in the status that it wants to
 211          * exit.
 212          */
 213         case PTRACE_KILL:
 214                 ret = 0;
 215                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 216                         break;
 217                 child->exit_code = SIGKILL;
 218                 child->ptrace &= ~PT_SINGLESTEP;
 219                 wake_up_process(child);
 220                 break;
 221
 222         case PTRACE_SINGLESTEP:
 223                 ret = -EIO;
 224                 if (!valid_signal(data))
 225                         break;
 226                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 227                 child->ptrace |= PT_SINGLESTEP;
 228                 child->exit_code = data;
 229                 wake_up_process(child);
 230                 ret = 0;
 231                 break;
 232
 233         case PTRACE_GETREGS:
 234         {
 235                 /* 'data' points to user memory in which to write.
 236                  * Mainly due to the non-live register values, we
 237                  * reformat the register values into something more
 238                  * standard.  For convenience, we use the handy
 239                  * elf_gregset_t format. */
 240
 241                 xtensa_gregset_t format;
 242                 struct pt_regs *regs = task_pt_regs(child);
 243
 244                 do_copy_regs (&format, regs, child);
 245
 246                 /* Now, copy to user space nice and easy... */
 247                 ret = 0;
 248                 if (copy_to_user((void *)data, &format, sizeof(elf_gregset_t)))
 249                         ret = -EFAULT;
 250                 break;
 251         }
 252
 253         case PTRACE_SETREGS:
 254         {
 255                 /* 'data' points to user memory that contains the new
 256                  * values in the elf_gregset_t format. */
 257
 258                 xtensa_gregset_t format;
 259                 struct pt_regs *regs = task_pt_regs(child);
 260
 261                 if (copy_from_user(&format,(void *)data,sizeof(elf_gregset_t))){
 262                         ret = -EFAULT;
 263                         break;
 264                 }
 265
 266                 /* FIXME: Perhaps we want some sanity checks on
 267                  * these user-space values?  See ARM version.  Are
 268                  * debuggers a security concern? */
 269
 270                 do_restore_regs (&format, regs, child);
 271
 272                 ret = 0;
 273                 break;
 274         }
 275
 276         case PTRACE_GETFPREGS:
 277         {
 278                 /* 'data' points to user memory in which to write.
 279                  * For convenience, we use the handy
 280                  * elf_fpregset_t format. */
 281
 282                 elf_fpregset_t fpregs;
 283                 struct pt_regs *regs = task_pt_regs(child);
 284
 285                 do_save_fpregs (&fpregs, regs, child);
 286
 287                 /* Now, copy to user space nice and easy... */
 288                 ret = 0;
 289                 if (copy_to_user((void *)data, &fpregs, sizeof(elf_fpregset_t)))
 290                         ret = -EFAULT;
 291
 292                 break;
 293         }
 294
 295         case PTRACE_SETFPREGS:
 296         {
 297                 /* 'data' points to user memory that contains the new
 298                  * values in the elf_fpregset_t format.
 299                  */
 300                 elf_fpregset_t fpregs;
 301                 struct pt_regs *regs = task_pt_regs(child);
 302
 303                 ret = 0;
 304                 if (copy_from_user(&fpregs, (void *)data, sizeof(elf_fpregset_t))) {
 305                         ret = -EFAULT;
 306                         break;
 307                 }
 308
 309                 if (do_restore_fpregs (&fpregs, regs, child))
 310                         ret = -EIO;
 311                 break;
 312         }
 313
 314         case PTRACE_GETFPREGSIZE:
 315                 /* 'data' points to 'unsigned long' set to the size
 316                  * of elf_fpregset_t
 317                  */
 318                 ret = put_user(sizeof(elf_fpregset_t), (unsigned long *) data);
 319                 break;
 320
 321         case PTRACE_DETACH: /* detach a process that was attached. */
 322                 ret = ptrace_detach(child, data);
 323                 break;
 324
 325         default:
 326                 ret = ptrace_request(child, request, addr, data);
 327                 goto out;
 328         }
 329  out:
 330         return ret;
 331 }
 332
 333 void do_syscall_trace(void)
 334 {
 335         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 336                 return;
 337
 338         if (!(current->ptrace & PT_PTRACED))
 339                 return;
 340
 341         /*
 342          * The 0x80 provides a way for the tracing parent to distinguish
 343          * between a syscall stop and SIGTRAP delivery
 344          */
 345         ptrace_notify(SIGTRAP|((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));
 346
 347         /*
 348          * this isn't the same as continuing with a signal, but it will do
 349          * for normal use.  strace only continues with a signal if the
 350          * stopping signal is not SIGTRAP.  -brl
 351          */
 352         if (current->exit_code) {
 353                 send_sig(current->exit_code, current, 1);
 354                 current->exit_code = 0;
 355         }
 356 }