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 #include <linux/signal.h>
  30 #include <linux/seccomp.h>
  31 #include <linux/audit.h>
  32 #include <linux/module.h>
  33
  34 #include <asm/uaccess.h>
  35 #include <asm/page.h>
  36 #include <asm/pgtable.h>
  37 #include <asm/system.h>
  38
  39 /*
  40  * Set of msr bits that gdb can change on behalf of a process.
  41  */
  42 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
  43 #define MSR_DEBUGCHANGE 0
  44 #else
  45 #define MSR_DEBUGCHANGE (MSR_SE | MSR_BE)
  46 #endif
  47
  48 /*
  49  * does not yet catch signals sent when the child dies.
  50  * in exit.c or in signal.c.
  51  */
  52
  53 /*
  54  * Get contents of register REGNO in task TASK.
  55  */
  56 static inline unsigned long get_reg(struct task_struct *task, int regno)
  57 {
  58         if (regno < sizeof(struct pt_regs) / sizeof(unsigned long)
  59             && task->thread.regs != NULL)
  60                 return ((unsigned long *)task->thread.regs)[regno];
  61         return (0);
  62 }
  63
  64 /*
  65  * Write contents of register REGNO in task TASK.
  66  */
  67 static inline int put_reg(struct task_struct *task, int regno,
  68                           unsigned long data)
  69 {
  70         if (regno <= PT_MQ && task->thread.regs != NULL) {
  71                 if (regno == PT_MSR)
  72                         data = (data & MSR_DEBUGCHANGE)
  73                                 | (task->thread.regs->msr & ~MSR_DEBUGCHANGE);
  74                 ((unsigned long *)task->thread.regs)[regno] = data;
  75                 return 0;
  76         }
  77         return -EIO;
  78 }
  79
  80 #ifdef CONFIG_ALTIVEC
  81 /*
  82  * Get contents of AltiVec register state in task TASK
  83  */
  84 static inline int get_vrregs(unsigned long __user *data, struct task_struct *task)
  85 {
  86         int i, j;
  87
  88         if (!access_ok(VERIFY_WRITE, data, 133 * sizeof(unsigned long)))
  89                 return -EFAULT;
  90
  91         /* copy AltiVec registers VR[0] .. VR[31] */
  92         for (i = 0; i < 32; i++)
  93                 for (j = 0; j < 4; j++, data++)
  94                         if (__put_user(task->thread.vr[i].u[j], data))
  95                                 return -EFAULT;
  96
  97         /* copy VSCR */
  98         for (i = 0; i < 4; i++, data++)
  99                 if (__put_user(task->thread.vscr.u[i], data))
 100                         return -EFAULT;
 101
 102         /* copy VRSAVE */
 103         if (__put_user(task->thread.vrsave, data))
 104                 return -EFAULT;
 105
 106         return 0;
 107 }
 108
 109 /*
 110  * Write contents of AltiVec register state into task TASK.
 111  */
 112 static inline int set_vrregs(struct task_struct *task, unsigned long __user *data)
 113 {
 114         int i, j;
 115
 116         if (!access_ok(VERIFY_READ, data, 133 * sizeof(unsigned long)))
 117                 return -EFAULT;
 118
 119         /* copy AltiVec registers VR[0] .. VR[31] */
 120         for (i = 0; i < 32; i++)
 121                 for (j = 0; j < 4; j++, data++)
 122                         if (__get_user(task->thread.vr[i].u[j], data))
 123                                 return -EFAULT;
 124
 125         /* copy VSCR */
 126         for (i = 0; i < 4; i++, data++)
 127                 if (__get_user(task->thread.vscr.u[i], data))
 128                         return -EFAULT;
 129
 130         /* copy VRSAVE */
 131         if (__get_user(task->thread.vrsave, data))
 132                 return -EFAULT;
 133
 134         return 0;
 135 }
 136 #endif
 137
 138 #ifdef CONFIG_SPE
 139
 140 /*
 141  * For get_evrregs/set_evrregs functions 'data' has the following layout:
 142  *
 143  * struct {
 144  *   u32 evr[32];
 145  *   u64 acc;
 146  *   u32 spefscr;
 147  * }
 148  */
 149
 150 /*
 151  * Get contents of SPE register state in task TASK.
 152  */
 153 static inline int get_evrregs(unsigned long *data, struct task_struct *task)
 154 {
 155         int i;
 156
 157         if (!access_ok(VERIFY_WRITE, data, 35 * sizeof(unsigned long)))
 158                 return -EFAULT;
 159
 160         /* copy SPEFSCR */
 161         if (__put_user(task->thread.spefscr, &data[34]))
 162                 return -EFAULT;
 163
 164         /* copy SPE registers EVR[0] .. EVR[31] */
 165         for (i = 0; i < 32; i++, data++)
 166                 if (__put_user(task->thread.evr[i], data))
 167                         return -EFAULT;
 168
 169         /* copy ACC */
 170         if (__put_user64(task->thread.acc, (unsigned long long *)data))
 171                 return -EFAULT;
 172
 173         return 0;
 174 }
 175
 176 /*
 177  * Write contents of SPE register state into task TASK.
 178  */
 179 static inline int set_evrregs(struct task_struct *task, unsigned long *data)
 180 {
 181         int i;
 182
 183         if (!access_ok(VERIFY_READ, data, 35 * sizeof(unsigned long)))
 184                 return -EFAULT;
 185
 186         /* copy SPEFSCR */
 187         if (__get_user(task->thread.spefscr, &data[34]))
 188                 return -EFAULT;
 189
 190         /* copy SPE registers EVR[0] .. EVR[31] */
 191         for (i = 0; i < 32; i++, data++)
 192                 if (__get_user(task->thread.evr[i], data))
 193                         return -EFAULT;
 194         /* copy ACC */
 195         if (__get_user64(task->thread.acc, (unsigned long long*)data))
 196                 return -EFAULT;
 197
 198         return 0;
 199 }
 200 #endif /* CONFIG_SPE */
 201
 202 static inline void
 203 set_single_step(struct task_struct *task)
 204 {
 205         struct pt_regs *regs = task->thread.regs;
 206
 207         if (regs != NULL) {
 208 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
 209                 task->thread.dbcr0 = DBCR0_IDM | DBCR0_IC;
 210                 regs->msr |= MSR_DE;
 211 #else
 212                 regs->msr |= MSR_SE;
 213 #endif
 214         }
 215 }
 216
 217 static inline void
 218 clear_single_step(struct task_struct *task)
 219 {
 220         struct pt_regs *regs = task->thread.regs;
 221
 222         if (regs != NULL) {
 223 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
 224                 task->thread.dbcr0 = 0;
 225                 regs->msr &= ~MSR_DE;
 226 #else
 227                 regs->msr &= ~MSR_SE;
 228 #endif
 229         }
 230 }
 231
 232 /*
 233  * Called by kernel/ptrace.c when detaching..
 234  *
 235  * Make sure single step bits etc are not set.
 236  */
 237 void ptrace_disable(struct task_struct *child)
 238 {
 239         /* make sure the single step bit is not set. */
 240         clear_single_step(child);
 241 }
 242
 243 int sys_ptrace(long request, long pid, long addr, long data)
 244 {
 245         struct task_struct *child;
 246         int ret = -EPERM;
 247
 248         lock_kernel();
 249         if (request == PTRACE_TRACEME) {
 250                 /* are we already being traced? */
 251                 if (current->ptrace & PT_PTRACED)
 252                         goto out;
 253                 ret = security_ptrace(current->parent, current);
 254                 if (ret)
 255                         goto out;
 256                 /* set the ptrace bit in the process flags. */
 257                 current->ptrace |= PT_PTRACED;
 258                 ret = 0;
 259                 goto out;
 260         }
 261         ret = -ESRCH;
 262         read_lock(&tasklist_lock);
 263         child = find_task_by_pid(pid);
 264         if (child)
 265                 get_task_struct(child);
 266         read_unlock(&tasklist_lock);
 267         if (!child)
 268                 goto out;
 269
 270         ret = -EPERM;
 271         if (pid == 1)           /* you may not mess with init */
 272                 goto out_tsk;
 273
 274         if (request == PTRACE_ATTACH) {
 275                 ret = ptrace_attach(child);
 276                 goto out_tsk;
 277         }
 278
 279         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 280         if (ret < 0)
 281                 goto out_tsk;
 282
 283         switch (request) {
 284         /* when I and D space are separate, these will need to be fixed. */
 285         case PTRACE_PEEKTEXT: /* read word at location addr. */
 286         case PTRACE_PEEKDATA: {
 287                 unsigned long tmp;
 288                 int copied;
 289
 290                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 291                 ret = -EIO;
 292                 if (copied != sizeof(tmp))
 293                         break;
 294                 ret = put_user(tmp,(unsigned long __user *) data);
 295                 break;
 296         }
 297
 298         /* read the word at location addr in the USER area. */
 299         /* XXX this will need fixing for 64-bit */
 300         case PTRACE_PEEKUSR: {
 301                 unsigned long index, tmp;
 302
 303                 ret = -EIO;
 304                 /* convert to index and check */
 305                 index = (unsigned long) addr >> 2;
 306                 if ((addr & 3) || index > PT_FPSCR
 307                     || child->thread.regs == NULL)
 308                         break;
 309
 310                 CHECK_FULL_REGS(child->thread.regs);
 311                 if (index < PT_FPR0) {
 312                         tmp = get_reg(child, (int) index);
 313                 } else {
 314                         preempt_disable();
 315                         if (child->thread.regs->msr & MSR_FP)
 316                                 giveup_fpu(child);
 317                         preempt_enable();
 318                         tmp = ((unsigned long *)child->thread.fpr)[index - PT_FPR0];
 319                 }
 320                 ret = put_user(tmp,(unsigned long __user *) data);
 321                 break;
 322         }
 323
 324         /* If I and D space are separate, this will have to be fixed. */
 325         case PTRACE_POKETEXT: /* write the word at location addr. */
 326         case PTRACE_POKEDATA:
 327                 ret = 0;
 328                 if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 329                         break;
 330                 ret = -EIO;
 331                 break;
 332
 333         /* write the word at location addr in the USER area */
 334         case PTRACE_POKEUSR: {
 335                 unsigned long index;
 336
 337                 ret = -EIO;
 338                 /* convert to index and check */
 339                 index = (unsigned long) addr >> 2;
 340                 if ((addr & 3) || index > PT_FPSCR
 341                     || child->thread.regs == NULL)
 342                         break;
 343
 344                 CHECK_FULL_REGS(child->thread.regs);
 345                 if (index == PT_ORIG_R3)
 346                         break;
 347                 if (index < PT_FPR0) {
 348                         ret = put_reg(child, index, data);
 349                 } else {
 350                         preempt_disable();
 351                         if (child->thread.regs->msr & MSR_FP)
 352                                 giveup_fpu(child);
 353                         preempt_enable();
 354                         ((unsigned long *)child->thread.fpr)[index - PT_FPR0] = data;
 355                         ret = 0;
 356                 }
 357                 break;
 358         }
 359
 360         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 361         case PTRACE_CONT: { /* restart after signal. */
 362                 ret = -EIO;
 363                 if (!valid_signal(data))
 364                         break;
 365                 if (request == PTRACE_SYSCALL) {
 366                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 367                 } else {
 368                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 369                 }
 370                 child->exit_code = data;
 371                 /* make sure the single step bit is not set. */
 372                 clear_single_step(child);
 373                 wake_up_process(child);
 374                 ret = 0;
 375                 break;
 376         }
 377
 378 /*
 379  * make the child exit.  Best I can do is send it a sigkill.
 380  * perhaps it should be put in the status that it wants to
 381  * exit.
 382  */
 383         case PTRACE_KILL: {
 384                 ret = 0;
 385                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 386                         break;
 387                 child->exit_code = SIGKILL;
 388                 /* make sure the single step bit is not set. */
 389                 clear_single_step(child);
 390                 wake_up_process(child);
 391                 break;
 392         }
 393
 394         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 395                 ret = -EIO;
 396                 if (!valid_signal(data))
 397                         break;
 398                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 399                 set_single_step(child);
 400                 child->exit_code = data;
 401                 /* give it a chance to run. */
 402                 wake_up_process(child);
 403                 ret = 0;
 404                 break;
 405         }
 406
 407         case PTRACE_DETACH:
 408                 ret = ptrace_detach(child, data);
 409                 break;
 410
 411 #ifdef CONFIG_ALTIVEC
 412         case PTRACE_GETVRREGS:
 413                 /* Get the child altivec register state. */
 414                 preempt_disable();
 415                 if (child->thread.regs->msr & MSR_VEC)
 416                         giveup_altivec(child);
 417                 preempt_enable();
 418                 ret = get_vrregs((unsigned long __user *)data, child);
 419                 break;
 420
 421         case PTRACE_SETVRREGS:
 422                 /* Set the child altivec register state. */
 423                 /* this is to clear the MSR_VEC bit to force a reload
 424                  * of register state from memory */
 425                 preempt_disable();
 426                 if (child->thread.regs->msr & MSR_VEC)
 427                         giveup_altivec(child);
 428                 preempt_enable();
 429                 ret = set_vrregs(child, (unsigned long __user *)data);
 430                 break;
 431 #endif
 432 #ifdef CONFIG_SPE
 433         case PTRACE_GETEVRREGS:
 434                 /* Get the child spe register state. */
 435                 if (child->thread.regs->msr & MSR_SPE)
 436                         giveup_spe(child);
 437                 ret = get_evrregs((unsigned long __user *)data, child);
 438                 break;
 439
 440         case PTRACE_SETEVRREGS:
 441                 /* Set the child spe register state. */
 442                 /* this is to clear the MSR_SPE bit to force a reload
 443                  * of register state from memory */
 444                 if (child->thread.regs->msr & MSR_SPE)
 445                         giveup_spe(child);
 446                 ret = set_evrregs(child, (unsigned long __user *)data);
 447                 break;
 448 #endif
 449
 450         default:
 451                 ret = ptrace_request(child, request, addr, data);
 452                 break;
 453         }
 454 out_tsk:
 455         put_task_struct(child);
 456 out:
 457         unlock_kernel();
 458         return ret;
 459 }
 460
 461 static void do_syscall_trace(void)
 462 {
 463         /* the 0x80 provides a way for the tracing parent to distinguish
 464            between a syscall stop and SIGTRAP delivery */
 465         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 466                                  ? 0x80 : 0));
 467
 468         /*
 469          * this isn't the same as continuing with a signal, but it will do
 470          * for normal use.  strace only continues with a signal if the
 471          * stopping signal is not SIGTRAP.  -brl
 472          */
 473         if (current->exit_code) {
 474                 send_sig(current->exit_code, current, 1);
 475                 current->exit_code = 0;
 476         }
 477 }
 478
 479 void do_syscall_trace_enter(struct pt_regs *regs)
 480 {
 481         if (test_thread_flag(TIF_SYSCALL_TRACE)
 482             && (current->ptrace & PT_PTRACED))
 483                 do_syscall_trace();
 484
 485         if (unlikely(current->audit_context))
 486                 audit_syscall_entry(current, AUDIT_ARCH_PPC,
 487                                     regs->gpr[0],
 488                                     regs->gpr[3], regs->gpr[4],
 489                                     regs->gpr[5], regs->gpr[6]);
 490 }
 491
 492 void do_syscall_trace_leave(struct pt_regs *regs)
 493 {
 494         secure_computing(regs->gpr[0]);
 495
 496         if (unlikely(current->audit_context))
 497                 audit_syscall_exit(current,
 498                                    (regs->ccr&0x1000)?AUDITSC_FAILURE:AUDITSC_SUCCESS,
 499                                    regs->result);
 500
 501         if ((test_thread_flag(TIF_SYSCALL_TRACE))
 502             && (current->ptrace & PT_PTRACED))
 503                 do_syscall_trace();
 504 }
 505
 506 EXPORT_SYMBOL(do_syscall_trace_enter);
 507 EXPORT_SYMBOL(do_syscall_trace_leave);