arch/ppc/kernel/ptrace.c

   1 /*
   2  *  arch/ppc/kernel/ptrace.c
   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@linuxcare.com.au).
  14  *
  15  * This file is subject to the terms and conditions of the GNU General
  16  * Public License.  See the file README.legal in the main directory of
  17  * this archive for more details.
  18  */
  19
  20 #include <linux/kernel.h>
  21 #include <linux/sched.h>
  22 #include <linux/mm.h>
  23 #include <linux/smp.h>
  24 #include <linux/smp_lock.h>
  25 #include <linux/errno.h>
  26 #include <linux/ptrace.h>
  27 #include <linux/user.h>
  28 #include <linux/security.h>
  29
  30 #include <asm/uaccess.h>
  31 #include <asm/page.h>
  32 #include <asm/pgtable.h>
  33 #include <asm/system.h>
  34
  35 /*
  36  * Set of msr bits that gdb can change on behalf of a process.
  37  */
  38 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
  39 #define MSR_DEBUGCHANGE 0
  40 #else
  41 #define MSR_DEBUGCHANGE (MSR_SE | MSR_BE)
  42 #endif
  43
  44 /*
  45  * does not yet catch signals sent when the child dies.
  46  * in exit.c or in signal.c.
  47  */
  48
  49 /*
  50  * Get contents of register REGNO in task TASK.
  51  */
  52 static inline unsigned long get_reg(struct task_struct *task, int regno)
  53 {
  54         if (regno < sizeof(struct pt_regs) / sizeof(unsigned long)
  55             && task->thread.regs != NULL)
  56                 return ((unsigned long *)task->thread.regs)[regno];
  57         return (0);
  58 }
  59
  60 /*
  61  * Write contents of register REGNO in task TASK.
  62  */
  63 static inline int put_reg(struct task_struct *task, int regno,
  64                           unsigned long data)
  65 {
  66         if (regno <= PT_MQ && task->thread.regs != NULL) {
  67                 if (regno == PT_MSR)
  68                         data = (data & MSR_DEBUGCHANGE)
  69                                 | (task->thread.regs->msr & ~MSR_DEBUGCHANGE);
  70                 ((unsigned long *)task->thread.regs)[regno] = data;
  71                 return 0;
  72         }
  73         return -EIO;
  74 }
  75
  76 #ifdef CONFIG_ALTIVEC
  77 /*
  78  * Get contents of AltiVec register state in task TASK
  79  */
  80 static inline int get_vrregs(unsigned long __user *data, struct task_struct *task)
  81 {
  82         int i, j;
  83
  84         if (!access_ok(VERIFY_WRITE, data, 133 * sizeof(unsigned long)))
  85                 return -EFAULT;
  86
  87         /* copy AltiVec registers VR[0] .. VR[31] */
  88         for (i = 0; i < 32; i++)
  89                 for (j = 0; j < 4; j++, data++)
  90                         if (__put_user(task->thread.vr[i].u[j], data))
  91                                 return -EFAULT;
  92
  93         /* copy VSCR */
  94         for (i = 0; i < 4; i++, data++)
  95                 if (__put_user(task->thread.vscr.u[i], data))
  96                         return -EFAULT;
  97
  98         /* copy VRSAVE */
  99         if (__put_user(task->thread.vrsave, data))
 100                 return -EFAULT;
 101
 102         return 0;
 103 }
 104
 105 /*
 106  * Write contents of AltiVec register state into task TASK.
 107  */
 108 static inline int set_vrregs(struct task_struct *task, unsigned long __user *data)
 109 {
 110         int i, j;
 111
 112         if (!access_ok(VERIFY_READ, data, 133 * sizeof(unsigned long)))
 113                 return -EFAULT;
 114
 115         /* copy AltiVec registers VR[0] .. VR[31] */
 116         for (i = 0; i < 32; i++)
 117                 for (j = 0; j < 4; j++, data++)
 118                         if (__get_user(task->thread.vr[i].u[j], data))
 119                                 return -EFAULT;
 120
 121         /* copy VSCR */
 122         for (i = 0; i < 4; i++, data++)
 123                 if (__get_user(task->thread.vscr.u[i], data))
 124                         return -EFAULT;
 125
 126         /* copy VRSAVE */
 127         if (__get_user(task->thread.vrsave, data))
 128                 return -EFAULT;
 129
 130         return 0;
 131 }
 132 #endif
 133
 134 #ifdef CONFIG_SPE
 135
 136 /*
 137  * For get_evrregs/set_evrregs functions 'data' has the following layout:
 138  *
 139  * struct {
 140  *   u32 evr[32];
 141  *   u64 acc;
 142  *   u32 spefscr;
 143  * }
 144  */
 145
 146 /*
 147  * Get contents of SPE register state in task TASK.
 148  */
 149 static inline int get_evrregs(unsigned long *data, struct task_struct *task)
 150 {
 151         int i;
 152
 153         if (!access_ok(VERIFY_WRITE, data, 35 * sizeof(unsigned long)))
 154                 return -EFAULT;
 155
 156         /* copy SPEFSCR */
 157         if (__put_user(task->thread.spefscr, &data[34]))
 158                 return -EFAULT;
 159
 160         /* copy SPE registers EVR[0] .. EVR[31] */
 161         for (i = 0; i < 32; i++, data++)
 162                 if (__put_user(task->thread.evr[i], data))
 163                         return -EFAULT;
 164
 165         /* copy ACC */
 166         if (__put_user64(task->thread.acc, (unsigned long long *)data))
 167                 return -EFAULT;
 168
 169         return 0;
 170 }
 171
 172 /*
 173  * Write contents of SPE register state into task TASK.
 174  */
 175 static inline int set_evrregs(struct task_struct *task, unsigned long *data)
 176 {
 177         int i;
 178
 179         if (!access_ok(VERIFY_READ, data, 35 * sizeof(unsigned long)))
 180                 return -EFAULT;
 181
 182         /* copy SPEFSCR */
 183         if (__get_user(task->thread.spefscr, &data[34]))
 184                 return -EFAULT;
 185
 186         /* copy SPE registers EVR[0] .. EVR[31] */
 187         for (i = 0; i < 32; i++, data++)
 188                 if (__get_user(task->thread.evr[i], data))
 189                         return -EFAULT;
 190         /* copy ACC */
 191         if (__get_user64(task->thread.acc, (unsigned long long*)data))
 192                 return -EFAULT;
 193
 194         return 0;
 195 }
 196 #endif /* CONFIG_SPE */
 197
 198 static inline void
 199 set_single_step(struct task_struct *task)
 200 {
 201         struct pt_regs *regs = task->thread.regs;
 202
 203         if (regs != NULL) {
 204 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
 205                 task->thread.dbcr0 = DBCR0_IDM | DBCR0_IC;
 206                 regs->msr |= MSR_DE;
 207 #else
 208                 regs->msr |= MSR_SE;
 209 #endif
 210         }
 211 }
 212
 213 static inline void
 214 clear_single_step(struct task_struct *task)
 215 {
 216         struct pt_regs *regs = task->thread.regs;
 217
 218         if (regs != NULL) {
 219 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
 220                 task->thread.dbcr0 = 0;
 221                 regs->msr &= ~MSR_DE;
 222 #else
 223                 regs->msr &= ~MSR_SE;
 224 #endif
 225         }
 226 }
 227
 228 /*
 229  * Called by kernel/ptrace.c when detaching..
 230  *
 231  * Make sure single step bits etc are not set.
 232  */
 233 void ptrace_disable(struct task_struct *child)
 234 {
 235         /* make sure the single step bit is not set. */
 236         clear_single_step(child);
 237 }
 238
 239 int sys_ptrace(long request, long pid, long addr, long data)
 240 {
 241         struct task_struct *child;
 242         int ret = -EPERM;
 243
 244         lock_kernel();
 245         if (request == PTRACE_TRACEME) {
 246                 /* are we already being traced? */
 247                 if (current->ptrace & PT_PTRACED)
 248                         goto out;
 249                 ret = security_ptrace(current->parent, current);
 250                 if (ret)
 251                         goto out;
 252                 /* set the ptrace bit in the process flags. */
 253                 current->ptrace |= PT_PTRACED;
 254                 ret = 0;
 255                 goto out;
 256         }
 257         ret = -ESRCH;
 258         read_lock(&tasklist_lock);
 259         child = find_task_by_pid(pid);
 260         if (child)
 261                 get_task_struct(child);
 262         read_unlock(&tasklist_lock);
 263         if (!child)
 264                 goto out;
 265
 266         ret = -EPERM;
 267         if (pid == 1)           /* you may not mess with init */
 268                 goto out_tsk;
 269
 270         if (request == PTRACE_ATTACH) {
 271                 ret = ptrace_attach(child);
 272                 goto out_tsk;
 273         }
 274
 275         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 276         if (ret < 0)
 277                 goto out_tsk;
 278
 279         switch (request) {
 280         /* when I and D space are separate, these will need to be fixed. */
 281         case PTRACE_PEEKTEXT: /* read word at location addr. */
 282         case PTRACE_PEEKDATA: {
 283                 unsigned long tmp;
 284                 int copied;
 285
 286                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 287                 ret = -EIO;
 288                 if (copied != sizeof(tmp))
 289                         break;
 290                 ret = put_user(tmp,(unsigned long __user *) data);
 291                 break;
 292         }
 293
 294         /* read the word at location addr in the USER area. */
 295         /* XXX this will need fixing for 64-bit */
 296         case PTRACE_PEEKUSR: {
 297                 unsigned long index, tmp;
 298
 299                 ret = -EIO;
 300                 /* convert to index and check */
 301                 index = (unsigned long) addr >> 2;
 302                 if ((addr & 3) || index > PT_FPSCR
 303                     || child->thread.regs == NULL)
 304                         break;
 305
 306                 CHECK_FULL_REGS(child->thread.regs);
 307                 if (index < PT_FPR0) {
 308                         tmp = get_reg(child, (int) index);
 309                 } else {
 310                         preempt_disable();
 311                         if (child->thread.regs->msr & MSR_FP)
 312                                 giveup_fpu(child);
 313                         preempt_enable();
 314                         tmp = ((unsigned long *)child->thread.fpr)[index - PT_FPR0];
 315                 }
 316                 ret = put_user(tmp,(unsigned long __user *) data);
 317                 break;
 318         }
 319
 320         /* If I and D space are separate, this will have to be fixed. */
 321         case PTRACE_POKETEXT: /* write the word at location addr. */
 322         case PTRACE_POKEDATA:
 323                 ret = 0;
 324                 if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 325                         break;
 326                 ret = -EIO;
 327                 break;
 328
 329         /* write the word at location addr in the USER area */
 330         case PTRACE_POKEUSR: {
 331                 unsigned long index;
 332
 333                 ret = -EIO;
 334                 /* convert to index and check */
 335                 index = (unsigned long) addr >> 2;
 336                 if ((addr & 3) || index > PT_FPSCR
 337                     || child->thread.regs == NULL)
 338                         break;
 339
 340                 CHECK_FULL_REGS(child->thread.regs);
 341                 if (index == PT_ORIG_R3)
 342                         break;
 343                 if (index < PT_FPR0) {
 344                         ret = put_reg(child, index, data);
 345                 } else {
 346                         preempt_disable();
 347                         if (child->thread.regs->msr & MSR_FP)
 348                                 giveup_fpu(child);
 349                         preempt_enable();
 350                         ((unsigned long *)child->thread.fpr)[index - PT_FPR0] = data;
 351                         ret = 0;
 352                 }
 353                 break;
 354         }
 355
 356         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 357         case PTRACE_CONT: { /* restart after signal. */
 358                 ret = -EIO;
 359                 if ((unsigned long) data > _NSIG)
 360                         break;
 361                 if (request == PTRACE_SYSCALL) {
 362                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 363                 } else {
 364                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 365                 }
 366                 child->exit_code = data;
 367                 /* make sure the single step bit is not set. */
 368                 clear_single_step(child);
 369                 wake_up_process(child);
 370                 ret = 0;
 371                 break;
 372         }
 373
 374 /*
 375  * make the child exit.  Best I can do is send it a sigkill.
 376  * perhaps it should be put in the status that it wants to
 377  * exit.
 378  */
 379         case PTRACE_KILL: {
 380                 ret = 0;
 381                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 382                         break;
 383                 child->exit_code = SIGKILL;
 384                 /* make sure the single step bit is not set. */
 385                 clear_single_step(child);
 386                 wake_up_process(child);
 387                 break;
 388         }
 389
 390         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 391                 ret = -EIO;
 392                 if ((unsigned long) data > _NSIG)
 393                         break;
 394                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 395                 set_single_step(child);
 396                 child->exit_code = data;
 397                 /* give it a chance to run. */
 398                 wake_up_process(child);
 399                 ret = 0;
 400                 break;
 401         }
 402
 403         case PTRACE_DETACH:
 404                 ret = ptrace_detach(child, data);
 405                 break;
 406
 407 #ifdef CONFIG_ALTIVEC
 408         case PTRACE_GETVRREGS:
 409                 /* Get the child altivec register state. */
 410                 preempt_disable();
 411                 if (child->thread.regs->msr & MSR_VEC)
 412                         giveup_altivec(child);
 413                 preempt_enable();
 414                 ret = get_vrregs((unsigned long __user *)data, child);
 415                 break;
 416
 417         case PTRACE_SETVRREGS:
 418                 /* Set the child altivec register state. */
 419                 /* this is to clear the MSR_VEC bit to force a reload
 420                  * of register state from memory */
 421                 preempt_disable();
 422                 if (child->thread.regs->msr & MSR_VEC)
 423                         giveup_altivec(child);
 424                 preempt_enable();
 425                 ret = set_vrregs(child, (unsigned long __user *)data);
 426                 break;
 427 #endif
 428 #ifdef CONFIG_SPE
 429         case PTRACE_GETEVRREGS:
 430                 /* Get the child spe register state. */
 431                 if (child->thread.regs->msr & MSR_SPE)
 432                         giveup_spe(child);
 433                 ret = get_evrregs((unsigned long __user *)data, child);
 434                 break;
 435
 436         case PTRACE_SETEVRREGS:
 437                 /* Set the child spe register state. */
 438                 /* this is to clear the MSR_SPE bit to force a reload
 439                  * of register state from memory */
 440                 if (child->thread.regs->msr & MSR_SPE)
 441                         giveup_spe(child);
 442                 ret = set_evrregs(child, (unsigned long __user *)data);
 443                 break;
 444 #endif
 445
 446         default:
 447                 ret = ptrace_request(child, request, addr, data);
 448                 break;
 449         }
 450 out_tsk:
 451         put_task_struct(child);
 452 out:
 453         unlock_kernel();
 454         return ret;
 455 }
 456
 457 void do_syscall_trace(void)
 458 {
 459         if (!test_thread_flag(TIF_SYSCALL_TRACE)
 460             || !(current->ptrace & PT_PTRACED))
 461                 return;
 462         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 463                                  ? 0x80 : 0));
 464
 465         /*
 466          * this isn't the same as continuing with a signal, but it will do
 467          * for normal use.  strace only continues with a signal if the
 468          * stopping signal is not SIGTRAP.  -brl
 469          */
 470         if (current->exit_code) {
 471                 send_sig(current->exit_code, current, 1);
 472                 current->exit_code = 0;
 473         }
 474 }