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