arch/powerpc/kernel/ptrace32.c

   1 /*
   2  * ptrace for 32-bit processes running on a 64-bit kernel.
   3  *
   4  *  PowerPC version
   5  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   6  *
   7  *  Derived from "arch/m68k/kernel/ptrace.c"
   8  *  Copyright (C) 1994 by Hamish Macdonald
   9  *  Taken from linux/kernel/ptrace.c and modified for M680x0.
  10  *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
  11  *
  12  * Modified by Cort Dougan (cort@hq.fsmlabs.com)
  13  * and Paul Mackerras (paulus@samba.org).
  14  *
  15  * This file is subject to the terms and conditions of the GNU General
  16  * Public License.  See the file COPYING in the main directory of
  17  * this archive for more details.
  18  */
  19
  20 #include <linux/config.h>
  21 #include <linux/kernel.h>
  22 #include <linux/sched.h>
  23 #include <linux/mm.h>
  24 #include <linux/smp.h>
  25 #include <linux/smp_lock.h>
  26 #include <linux/errno.h>
  27 #include <linux/ptrace.h>
  28 #include <linux/user.h>
  29 #include <linux/security.h>
  30 #include <linux/signal.h>
  31
  32 #include <asm/uaccess.h>
  33 #include <asm/page.h>
  34 #include <asm/pgtable.h>
  35 #include <asm/system.h>
  36 #include <asm/ptrace-common.h>
  37
  38 /*
  39  * does not yet catch signals sent when the child dies.
  40  * in exit.c or in signal.c.
  41  */
  42
  43 int compat_sys_ptrace(int request, int pid, unsigned long addr,
  44                       unsigned long data)
  45 {
  46         struct task_struct *child;
  47         int ret = -EPERM;
  48
  49         lock_kernel();
  50         if (request == PTRACE_TRACEME) {
  51                 /* are we already being traced? */
  52                 if (current->ptrace & PT_PTRACED)
  53                         goto out;
  54                 ret = security_ptrace(current->parent, current);
  55                 if (ret)
  56                         goto out;
  57                 /* set the ptrace bit in the process flags. */
  58                 current->ptrace |= PT_PTRACED;
  59                 ret = 0;
  60                 goto out;
  61         }
  62         ret = -ESRCH;
  63         read_lock(&tasklist_lock);
  64         child = find_task_by_pid(pid);
  65         if (child)
  66                 get_task_struct(child);
  67         read_unlock(&tasklist_lock);
  68         if (!child)
  69                 goto out;
  70
  71         ret = -EPERM;
  72         if (pid == 1)           /* you may not mess with init */
  73                 goto out_tsk;
  74
  75         if (request == PTRACE_ATTACH) {
  76                 ret = ptrace_attach(child);
  77                 goto out_tsk;
  78         }
  79
  80         ret = ptrace_check_attach(child, request == PTRACE_KILL);
  81         if (ret < 0)
  82                 goto out_tsk;
  83
  84         switch (request) {
  85         /* when I and D space are separate, these will need to be fixed. */
  86         case PTRACE_PEEKTEXT: /* read word at location addr. */
  87         case PTRACE_PEEKDATA: {
  88                 unsigned int tmp;
  89                 int copied;
  90
  91                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
  92                 ret = -EIO;
  93                 if (copied != sizeof(tmp))
  94                         break;
  95                 ret = put_user(tmp, (u32 __user *)data);
  96                 break;
  97         }
  98
  99         /*
 100          * Read 4 bytes of the other process' storage
 101          *  data is a pointer specifying where the user wants the
 102          *      4 bytes copied into
 103          *  addr is a pointer in the user's storage that contains an 8 byte
 104          *      address in the other process of the 4 bytes that is to be read
 105          * (this is run in a 32-bit process looking at a 64-bit process)
 106          * when I and D space are separate, these will need to be fixed.
 107          */
 108         case PPC_PTRACE_PEEKTEXT_3264:
 109         case PPC_PTRACE_PEEKDATA_3264: {
 110                 u32 tmp;
 111                 int copied;
 112                 u32 __user * addrOthers;
 113
 114                 ret = -EIO;
 115
 116                 /* Get the addr in the other process that we want to read */
 117                 if (get_user(addrOthers, (u32 __user * __user *)addr) != 0)
 118                         break;
 119
 120                 copied = access_process_vm(child, (u64)addrOthers, &tmp,
 121                                 sizeof(tmp), 0);
 122                 if (copied != sizeof(tmp))
 123                         break;
 124                 ret = put_user(tmp, (u32 __user *)data);
 125                 break;
 126         }
 127
 128         /* Read a register (specified by ADDR) out of the "user area" */
 129         case PTRACE_PEEKUSR: {
 130                 int index;
 131                 unsigned long tmp;
 132
 133                 ret = -EIO;
 134                 /* convert to index and check */
 135                 index = (unsigned long) addr >> 2;
 136                 if ((addr & 3) || (index > PT_FPSCR32))
 137                         break;
 138
 139                 if (index < PT_FPR0) {
 140                         tmp = get_reg(child, index);
 141                 } else {
 142                         flush_fp_to_thread(child);
 143                         /*
 144                          * the user space code considers the floating point
 145                          * to be an array of unsigned int (32 bits) - the
 146                          * index passed in is based on this assumption.
 147                          */
 148                         tmp = ((unsigned int *)child->thread.fpr)[index - PT_FPR0];
 149                 }
 150                 ret = put_user((unsigned int)tmp, (u32 __user *)data);
 151                 break;
 152         }
 153
 154         /*
 155          * Read 4 bytes out of the other process' pt_regs area
 156          *  data is a pointer specifying where the user wants the
 157          *      4 bytes copied into
 158          *  addr is the offset into the other process' pt_regs structure
 159          *      that is to be read
 160          * (this is run in a 32-bit process looking at a 64-bit process)
 161          */
 162         case PPC_PTRACE_PEEKUSR_3264: {
 163                 u32 index;
 164                 u32 reg32bits;
 165                 u64 tmp;
 166                 u32 numReg;
 167                 u32 part;
 168
 169                 ret = -EIO;
 170                 /* Determine which register the user wants */
 171                 index = (u64)addr >> 2;
 172                 numReg = index / 2;
 173                 /* Determine which part of the register the user wants */
 174                 if (index % 2)
 175                         part = 1;  /* want the 2nd half of the register (right-most). */
 176                 else
 177                         part = 0;  /* want the 1st half of the register (left-most). */
 178
 179                 /* Validate the input - check to see if address is on the wrong boundary or beyond the end of the user area */
 180                 if ((addr & 3) || numReg > PT_FPSCR)
 181                         break;
 182
 183                 if (numReg >= PT_FPR0) {
 184                         flush_fp_to_thread(child);
 185                         tmp = ((unsigned long int *)child->thread.fpr)[numReg - PT_FPR0];
 186                 } else { /* register within PT_REGS struct */
 187                         tmp = get_reg(child, numReg);
 188                 }
 189                 reg32bits = ((u32*)&tmp)[part];
 190                 ret = put_user(reg32bits, (u32 __user *)data);
 191                 break;
 192         }
 193
 194         /* If 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                 unsigned int tmp;
 198                 tmp = data;
 199                 ret = 0;
 200                 if (access_process_vm(child, addr, &tmp, sizeof(tmp), 1)
 201                                 == sizeof(tmp))
 202                         break;
 203                 ret = -EIO;
 204                 break;
 205         }
 206
 207         /*
 208          * Write 4 bytes into the other process' storage
 209          *  data is the 4 bytes that the user wants written
 210          *  addr is a pointer in the user's storage that contains an
 211          *      8 byte address in the other process where the 4 bytes
 212          *      that is to be written
 213          * (this is run in a 32-bit process looking at a 64-bit process)
 214          * when I and D space are separate, these will need to be fixed.
 215          */
 216         case PPC_PTRACE_POKETEXT_3264:
 217         case PPC_PTRACE_POKEDATA_3264: {
 218                 u32 tmp = data;
 219                 u32 __user * addrOthers;
 220
 221                 /* Get the addr in the other process that we want to write into */
 222                 ret = -EIO;
 223                 if (get_user(addrOthers, (u32 __user * __user *)addr) != 0)
 224                         break;
 225                 ret = 0;
 226                 if (access_process_vm(child, (u64)addrOthers, &tmp,
 227                                         sizeof(tmp), 1) == sizeof(tmp))
 228                         break;
 229                 ret = -EIO;
 230                 break;
 231         }
 232
 233         /* write the word at location addr in the USER area */
 234         case PTRACE_POKEUSR: {
 235                 unsigned long index;
 236
 237                 ret = -EIO;
 238                 /* convert to index and check */
 239                 index = (unsigned long) addr >> 2;
 240                 if ((addr & 3) || (index > PT_FPSCR32))
 241                         break;
 242
 243                 if (index == PT_ORIG_R3)
 244                         break;
 245                 if (index < PT_FPR0) {
 246                         ret = put_reg(child, index, data);
 247                 } else {
 248                         flush_fp_to_thread(child);
 249                         /*
 250                          * the user space code considers the floating point
 251                          * to be an array of unsigned int (32 bits) - the
 252                          * index passed in is based on this assumption.
 253                          */
 254                         ((unsigned int *)child->thread.fpr)[index - PT_FPR0] = data;
 255                         ret = 0;
 256                 }
 257                 break;
 258         }
 259
 260         /*
 261          * Write 4 bytes into the other process' pt_regs area
 262          *  data is the 4 bytes that the user wants written
 263          *  addr is the offset into the other process' pt_regs structure
 264          *      that is to be written into
 265          * (this is run in a 32-bit process looking at a 64-bit process)
 266          */
 267         case PPC_PTRACE_POKEUSR_3264: {
 268                 u32 index;
 269                 u32 numReg;
 270
 271                 ret = -EIO;
 272                 /* Determine which register the user wants */
 273                 index = (u64)addr >> 2;
 274                 numReg = index / 2;
 275                 /*
 276                  * Validate the input - check to see if address is on the
 277                  * wrong boundary or beyond the end of the user area
 278                  */
 279                 if ((addr & 3) || (numReg > PT_FPSCR))
 280                         break;
 281                 /* Insure it is a register we let them change */
 282                 if ((numReg == PT_ORIG_R3)
 283                                 || ((numReg > PT_CCR) && (numReg < PT_FPR0)))
 284                         break;
 285                 if (numReg >= PT_FPR0) {
 286                         flush_fp_to_thread(child);
 287                 }
 288                 if (numReg == PT_MSR)
 289                         data = (data & MSR_DEBUGCHANGE)
 290                                 | (child->thread.regs->msr & ~MSR_DEBUGCHANGE);
 291                 ((u32*)child->thread.regs)[index] = data;
 292                 ret = 0;
 293                 break;
 294         }
 295
 296         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 297         case PTRACE_CONT: { /* restart after signal. */
 298                 ret = -EIO;
 299                 if (!valid_signal(data))
 300                         break;
 301                 if (request == PTRACE_SYSCALL)
 302                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 303                 else
 304                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 305                 child->exit_code = data;
 306                 /* make sure the single step bit is not set. */
 307                 clear_single_step(child);
 308                 wake_up_process(child);
 309                 ret = 0;
 310                 break;
 311         }
 312
 313         /*
 314          * make the child exit.  Best I can do is send it a sigkill.
 315          * perhaps it should be put in the status that it wants to
 316          * exit.
 317          */
 318         case PTRACE_KILL: {
 319                 ret = 0;
 320                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 321                         break;
 322                 child->exit_code = SIGKILL;
 323                 /* make sure the single step bit is not set. */
 324                 clear_single_step(child);
 325                 wake_up_process(child);
 326                 break;
 327         }
 328
 329         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 330                 ret = -EIO;
 331                 if (!valid_signal(data))
 332                         break;
 333                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 334                 set_single_step(child);
 335                 child->exit_code = data;
 336                 /* give it a chance to run. */
 337                 wake_up_process(child);
 338                 ret = 0;
 339                 break;
 340         }
 341
 342         case PTRACE_GET_DEBUGREG: {
 343                 ret = -EINVAL;
 344                 /* We only support one DABR and no IABRS at the moment */
 345                 if (addr > 0)
 346                         break;
 347                 ret = put_user(child->thread.dabr, (u32 __user *)data);
 348                 break;
 349         }
 350
 351         case PTRACE_SET_DEBUGREG:
 352                 ret = ptrace_set_debugreg(child, addr, data);
 353                 break;
 354
 355         case PTRACE_DETACH:
 356                 ret = ptrace_detach(child, data);
 357                 break;
 358
 359         case PPC_PTRACE_GETREGS: { /* Get GPRs 0 - 31. */
 360                 int i;
 361                 unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
 362                 unsigned int __user *tmp = (unsigned int __user *)addr;
 363
 364                 for (i = 0; i < 32; i++) {
 365                         ret = put_user(*reg, tmp);
 366                         if (ret)
 367                                 break;
 368                         reg++;
 369                         tmp++;
 370                 }
 371                 break;
 372         }
 373
 374         case PPC_PTRACE_SETREGS: { /* Set GPRs 0 - 31. */
 375                 int i;
 376                 unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
 377                 unsigned int __user *tmp = (unsigned int __user *)addr;
 378
 379                 for (i = 0; i < 32; i++) {
 380                         ret = get_user(*reg, tmp);
 381                         if (ret)
 382                                 break;
 383                         reg++;
 384                         tmp++;
 385                 }
 386                 break;
 387         }
 388
 389         case PPC_PTRACE_GETFPREGS: { /* Get FPRs 0 - 31. */
 390                 int i;
 391                 unsigned long *reg = &((unsigned long *)child->thread.fpr)[0];
 392                 unsigned int __user *tmp = (unsigned int __user *)addr;
 393
 394                 flush_fp_to_thread(child);
 395
 396                 for (i = 0; i < 32; i++) {
 397                         ret = put_user(*reg, tmp);
 398                         if (ret)
 399                                 break;
 400                         reg++;
 401                         tmp++;
 402                 }
 403                 break;
 404         }
 405
 406         case PPC_PTRACE_SETFPREGS: { /* Get FPRs 0 - 31. */
 407                 int i;
 408                 unsigned long *reg = &((unsigned long *)child->thread.fpr)[0];
 409                 unsigned int __user *tmp = (unsigned int __user *)addr;
 410
 411                 flush_fp_to_thread(child);
 412
 413                 for (i = 0; i < 32; i++) {
 414                         ret = get_user(*reg, tmp);
 415                         if (ret)
 416                                 break;
 417                         reg++;
 418                         tmp++;
 419                 }
 420                 break;
 421         }
 422
 423         case PTRACE_GETEVENTMSG:
 424                 ret = put_user(child->ptrace_message, (unsigned int __user *) data);
 425                 break;
 426
 427 #ifdef CONFIG_ALTIVEC
 428         case PTRACE_GETVRREGS:
 429                 /* Get the child altivec register state. */
 430                 flush_altivec_to_thread(child);
 431                 ret = get_vrregs((unsigned long __user *)data, child);
 432                 break;
 433
 434         case PTRACE_SETVRREGS:
 435                 /* Set the child altivec register state. */
 436                 flush_altivec_to_thread(child);
 437                 ret = set_vrregs(child, (unsigned long __user *)data);
 438                 break;
 439 #endif
 440
 441         default:
 442                 ret = ptrace_request(child, request, addr, data);
 443                 break;
 444         }
 445 out_tsk:
 446         put_task_struct(child);
 447 out:
 448         unlock_kernel();
 449         return ret;
 450 }