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
  37 #include "ptrace-common.h"
  38
  39 /*
  40  * does not yet catch signals sent when the child dies.
  41  * in exit.c or in signal.c.
  42  */
  43
  44 long compat_sys_ptrace(int request, int pid, unsigned long addr,
  45                        unsigned long data)
  46 {
  47         struct task_struct *child;
  48         int ret = -EPERM;
  49
  50         lock_kernel();
  51         if (request == PTRACE_TRACEME) {
  52                 /* are we already being traced? */
  53                 if (current->ptrace & PT_PTRACED)
  54                         goto out;
  55                 ret = security_ptrace(current->parent, current);
  56                 if (ret)
  57                         goto out;
  58                 /* set the ptrace bit in the process flags. */
  59                 current->ptrace |= PT_PTRACED;
  60                 ret = 0;
  61                 goto out;
  62         }
  63         ret = -ESRCH;
  64         read_lock(&tasklist_lock);
  65         child = find_task_by_pid(pid);
  66         if (child)
  67                 get_task_struct(child);
  68         read_unlock(&tasklist_lock);
  69         if (!child)
  70                 goto out;
  71
  72         ret = -EPERM;
  73         if (pid == 1)           /* you may not mess with init */
  74                 goto out_tsk;
  75
  76         if (request == PTRACE_ATTACH) {
  77                 ret = ptrace_attach(child);
  78                 goto out_tsk;
  79         }
  80
  81         ret = ptrace_check_attach(child, request == PTRACE_KILL);
  82         if (ret < 0)
  83                 goto out_tsk;
  84
  85         switch (request) {
  86         /* when I and D space are separate, these will need to be fixed. */
  87         case PTRACE_PEEKTEXT: /* read word at location addr. */
  88         case PTRACE_PEEKDATA: {
  89                 unsigned int tmp;
  90                 int copied;
  91
  92                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
  93                 ret = -EIO;
  94                 if (copied != sizeof(tmp))
  95                         break;
  96                 ret = put_user(tmp, (u32 __user *)data);
  97                 break;
  98         }
  99
 100         /*
 101          * Read 4 bytes of the other process' storage
 102          *  data is a pointer specifying where the user wants the
 103          *      4 bytes copied into
 104          *  addr is a pointer in the user's storage that contains an 8 byte
 105          *      address in the other process of the 4 bytes that is to be read
 106          * (this is run in a 32-bit process looking at a 64-bit process)
 107          * when I and D space are separate, these will need to be fixed.
 108          */
 109         case PPC_PTRACE_PEEKTEXT_3264:
 110         case PPC_PTRACE_PEEKDATA_3264: {
 111                 u32 tmp;
 112                 int copied;
 113                 u32 __user * addrOthers;
 114
 115                 ret = -EIO;
 116
 117                 /* Get the addr in the other process that we want to read */
 118                 if (get_user(addrOthers, (u32 __user * __user *)addr) != 0)
 119                         break;
 120
 121                 copied = access_process_vm(child, (u64)addrOthers, &tmp,
 122                                 sizeof(tmp), 0);
 123                 if (copied != sizeof(tmp))
 124                         break;
 125                 ret = put_user(tmp, (u32 __user *)data);
 126                 break;
 127         }
 128
 129         /* Read a register (specified by ADDR) out of the "user area" */
 130         case PTRACE_PEEKUSR: {
 131                 int index;
 132                 unsigned long tmp;
 133
 134                 ret = -EIO;
 135                 /* convert to index and check */
 136                 index = (unsigned long) addr >> 2;
 137                 if ((addr & 3) || (index > PT_FPSCR32))
 138                         break;
 139
 140                 if (index < PT_FPR0) {
 141                         tmp = get_reg(child, index);
 142                 } else {
 143                         flush_fp_to_thread(child);
 144                         /*
 145                          * the user space code considers the floating point
 146                          * to be an array of unsigned int (32 bits) - the
 147                          * index passed in is based on this assumption.
 148                          */
 149                         tmp = ((unsigned int *)child->thread.fpr)[index - PT_FPR0];
 150                 }
 151                 ret = put_user((unsigned int)tmp, (u32 __user *)data);
 152                 break;
 153         }
 154
 155         /*
 156          * Read 4 bytes out of the other process' pt_regs area
 157          *  data is a pointer specifying where the user wants the
 158          *      4 bytes copied into
 159          *  addr is the offset into the other process' pt_regs structure
 160          *      that is to be read
 161          * (this is run in a 32-bit process looking at a 64-bit process)
 162          */
 163         case PPC_PTRACE_PEEKUSR_3264: {
 164                 u32 index;
 165                 u32 reg32bits;
 166                 u64 tmp;
 167                 u32 numReg;
 168                 u32 part;
 169
 170                 ret = -EIO;
 171                 /* Determine which register the user wants */
 172                 index = (u64)addr >> 2;
 173                 numReg = index / 2;
 174                 /* Determine which part of the register the user wants */
 175                 if (index % 2)
 176                         part = 1;  /* want the 2nd half of the register (right-most). */
 177                 else
 178                         part = 0;  /* want the 1st half of the register (left-most). */
 179
 180                 /* Validate the input - check to see if address is on the wrong boundary or beyond the end of the user area */
 181                 if ((addr & 3) || numReg > PT_FPSCR)
 182                         break;
 183
 184                 if (numReg >= PT_FPR0) {
 185                         flush_fp_to_thread(child);
 186                         tmp = ((unsigned long int *)child->thread.fpr)[numReg - PT_FPR0];
 187                 } else { /* register within PT_REGS struct */
 188                         tmp = get_reg(child, numReg);
 189                 }
 190                 reg32bits = ((u32*)&tmp)[part];
 191                 ret = put_user(reg32bits, (u32 __user *)data);
 192                 break;
 193         }
 194
 195         /* If I and D space are separate, this will have to be fixed. */
 196         case PTRACE_POKETEXT: /* write the word at location addr. */
 197         case PTRACE_POKEDATA: {
 198                 unsigned int tmp;
 199                 tmp = data;
 200                 ret = 0;
 201                 if (access_process_vm(child, addr, &tmp, sizeof(tmp), 1)
 202                                 == sizeof(tmp))
 203                         break;
 204                 ret = -EIO;
 205                 break;
 206         }
 207
 208         /*
 209          * Write 4 bytes into the other process' storage
 210          *  data is the 4 bytes that the user wants written
 211          *  addr is a pointer in the user's storage that contains an
 212          *      8 byte address in the other process where the 4 bytes
 213          *      that is to be written
 214          * (this is run in a 32-bit process looking at a 64-bit process)
 215          * when I and D space are separate, these will need to be fixed.
 216          */
 217         case PPC_PTRACE_POKETEXT_3264:
 218         case PPC_PTRACE_POKEDATA_3264: {
 219                 u32 tmp = data;
 220                 u32 __user * addrOthers;
 221
 222                 /* Get the addr in the other process that we want to write into */
 223                 ret = -EIO;
 224                 if (get_user(addrOthers, (u32 __user * __user *)addr) != 0)
 225                         break;
 226                 ret = 0;
 227                 if (access_process_vm(child, (u64)addrOthers, &tmp,
 228                                         sizeof(tmp), 1) == sizeof(tmp))
 229                         break;
 230                 ret = -EIO;
 231                 break;
 232         }
 233
 234         /* write the word at location addr in the USER area */
 235         case PTRACE_POKEUSR: {
 236                 unsigned long index;
 237
 238                 ret = -EIO;
 239                 /* convert to index and check */
 240                 index = (unsigned long) addr >> 2;
 241                 if ((addr & 3) || (index > PT_FPSCR32))
 242                         break;
 243
 244                 if (index == PT_ORIG_R3)
 245                         break;
 246                 if (index < PT_FPR0) {
 247                         ret = put_reg(child, index, data);
 248                 } else {
 249                         flush_fp_to_thread(child);
 250                         /*
 251                          * the user space code considers the floating point
 252                          * to be an array of unsigned int (32 bits) - the
 253                          * index passed in is based on this assumption.
 254                          */
 255                         ((unsigned int *)child->thread.fpr)[index - PT_FPR0] = data;
 256                         ret = 0;
 257                 }
 258                 break;
 259         }
 260
 261         /*
 262          * Write 4 bytes into the other process' pt_regs area
 263          *  data is the 4 bytes that the user wants written
 264          *  addr is the offset into the other process' pt_regs structure
 265          *      that is to be written into
 266          * (this is run in a 32-bit process looking at a 64-bit process)
 267          */
 268         case PPC_PTRACE_POKEUSR_3264: {
 269                 u32 index;
 270                 u32 numReg;
 271
 272                 ret = -EIO;
 273                 /* Determine which register the user wants */
 274                 index = (u64)addr >> 2;
 275                 numReg = index / 2;
 276                 /*
 277                  * Validate the input - check to see if address is on the
 278                  * wrong boundary or beyond the end of the user area
 279                  */
 280                 if ((addr & 3) || (numReg > PT_FPSCR))
 281                         break;
 282                 /* Insure it is a register we let them change */
 283                 if ((numReg == PT_ORIG_R3)
 284                                 || ((numReg > PT_CCR) && (numReg < PT_FPR0)))
 285                         break;
 286                 if (numReg >= PT_FPR0) {
 287                         flush_fp_to_thread(child);
 288                 }
 289                 if (numReg == PT_MSR)
 290                         data = (data & MSR_DEBUGCHANGE)
 291                                 | (child->thread.regs->msr & ~MSR_DEBUGCHANGE);
 292                 ((u32*)child->thread.regs)[index] = data;
 293                 ret = 0;
 294                 break;
 295         }
 296
 297         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 298         case PTRACE_CONT: { /* restart after signal. */
 299                 ret = -EIO;
 300                 if (!valid_signal(data))
 301                         break;
 302                 if (request == PTRACE_SYSCALL)
 303                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 304                 else
 305                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 306                 child->exit_code = data;
 307                 /* make sure the single step bit is not set. */
 308                 clear_single_step(child);
 309                 wake_up_process(child);
 310                 ret = 0;
 311                 break;
 312         }
 313
 314         /*
 315          * make the child exit.  Best I can do is send it a sigkill.
 316          * perhaps it should be put in the status that it wants to
 317          * exit.
 318          */
 319         case PTRACE_KILL: {
 320                 ret = 0;
 321                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 322                         break;
 323                 child->exit_code = SIGKILL;
 324                 /* make sure the single step bit is not set. */
 325                 clear_single_step(child);
 326                 wake_up_process(child);
 327                 break;
 328         }
 329
 330         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 331                 ret = -EIO;
 332                 if (!valid_signal(data))
 333                         break;
 334                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 335                 set_single_step(child);
 336                 child->exit_code = data;
 337                 /* give it a chance to run. */
 338                 wake_up_process(child);
 339                 ret = 0;
 340                 break;
 341         }
 342
 343         case PTRACE_GET_DEBUGREG: {
 344                 ret = -EINVAL;
 345                 /* We only support one DABR and no IABRS at the moment */
 346                 if (addr > 0)
 347                         break;
 348                 ret = put_user(child->thread.dabr, (u32 __user *)data);
 349                 break;
 350         }
 351
 352         case PTRACE_SET_DEBUGREG:
 353                 ret = ptrace_set_debugreg(child, addr, data);
 354                 break;
 355
 356         case PTRACE_DETACH:
 357                 ret = ptrace_detach(child, data);
 358                 break;
 359
 360         case PPC_PTRACE_GETREGS: { /* Get GPRs 0 - 31. */
 361                 int i;
 362                 unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
 363                 unsigned int __user *tmp = (unsigned int __user *)addr;
 364
 365                 for (i = 0; i < 32; i++) {
 366                         ret = put_user(*reg, tmp);
 367                         if (ret)
 368                                 break;
 369                         reg++;
 370                         tmp++;
 371                 }
 372                 break;
 373         }
 374
 375         case PPC_PTRACE_SETREGS: { /* Set GPRs 0 - 31. */
 376                 int i;
 377                 unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
 378                 unsigned int __user *tmp = (unsigned int __user *)addr;
 379
 380                 for (i = 0; i < 32; i++) {
 381                         ret = get_user(*reg, tmp);
 382                         if (ret)
 383                                 break;
 384                         reg++;
 385                         tmp++;
 386                 }
 387                 break;
 388         }
 389
 390         case PPC_PTRACE_GETFPREGS: { /* Get FPRs 0 - 31. */
 391                 int i;
 392                 unsigned long *reg = &((unsigned long *)child->thread.fpr)[0];
 393                 unsigned int __user *tmp = (unsigned int __user *)addr;
 394
 395                 flush_fp_to_thread(child);
 396
 397                 for (i = 0; i < 32; i++) {
 398                         ret = put_user(*reg, tmp);
 399                         if (ret)
 400                                 break;
 401                         reg++;
 402                         tmp++;
 403                 }
 404                 break;
 405         }
 406
 407         case PPC_PTRACE_SETFPREGS: { /* Get FPRs 0 - 31. */
 408                 int i;
 409                 unsigned long *reg = &((unsigned long *)child->thread.fpr)[0];
 410                 unsigned int __user *tmp = (unsigned int __user *)addr;
 411
 412                 flush_fp_to_thread(child);
 413
 414                 for (i = 0; i < 32; i++) {
 415                         ret = get_user(*reg, tmp);
 416                         if (ret)
 417                                 break;
 418                         reg++;
 419                         tmp++;
 420                 }
 421                 break;
 422         }
 423
 424         case PTRACE_GETEVENTMSG:
 425                 ret = put_user(child->ptrace_message, (unsigned int __user *) data);
 426                 break;
 427
 428 #ifdef CONFIG_ALTIVEC
 429         case PTRACE_GETVRREGS:
 430                 /* Get the child altivec register state. */
 431                 flush_altivec_to_thread(child);
 432                 ret = get_vrregs((unsigned long __user *)data, child);
 433                 break;
 434
 435         case PTRACE_SETVRREGS:
 436                 /* Set the child altivec register state. */
 437                 flush_altivec_to_thread(child);
 438                 ret = set_vrregs(child, (unsigned long __user *)data);
 439                 break;
 440 #endif
 441
 442         default:
 443                 ret = ptrace_request(child, request, addr, data);
 444                 break;
 445         }
 446 out_tsk:
 447         put_task_struct(child);
 448 out:
 449         unlock_kernel();
 450         return ret;
 451 }