arch/mn10300/kernel/ptrace.c

   1 /* MN10300 Process tracing
   2  *
   3  * Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
   4  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   5  * Modified by David Howells (dhowells@redhat.com)
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public Licence
   9  * as published by the Free Software Foundation; either version
  10  * 2 of the Licence, or (at your option) any later version.
  11  */
  12 #include <linux/kernel.h>
  13 #include <linux/sched.h>
  14 #include <linux/mm.h>
  15 #include <linux/smp.h>
  16 #include <linux/smp_lock.h>
  17 #include <linux/errno.h>
  18 #include <linux/ptrace.h>
  19 #include <linux/user.h>
  20 #include <asm/uaccess.h>
  21 #include <asm/pgtable.h>
  22 #include <asm/system.h>
  23 #include <asm/processor.h>
  24 #include <asm/cacheflush.h>
  25 #include <asm/fpu.h>
  26 #include <asm/asm-offsets.h>
  27
  28 /*
  29  * translate ptrace register IDs into struct pt_regs offsets
  30  */
  31 static const u8 ptrace_regid_to_frame[] = {
  32         [PT_A3 << 2]            = REG_A3,
  33         [PT_A2 << 2]            = REG_A2,
  34         [PT_D3 << 2]            = REG_D3,
  35         [PT_D2 << 2]            = REG_D2,
  36         [PT_MCVF << 2]          = REG_MCVF,
  37         [PT_MCRL << 2]          = REG_MCRL,
  38         [PT_MCRH << 2]          = REG_MCRH,
  39         [PT_MDRQ << 2]          = REG_MDRQ,
  40         [PT_E1 << 2]            = REG_E1,
  41         [PT_E0 << 2]            = REG_E0,
  42         [PT_E7 << 2]            = REG_E7,
  43         [PT_E6 << 2]            = REG_E6,
  44         [PT_E5 << 2]            = REG_E5,
  45         [PT_E4 << 2]            = REG_E4,
  46         [PT_E3 << 2]            = REG_E3,
  47         [PT_E2 << 2]            = REG_E2,
  48         [PT_SP << 2]            = REG_SP,
  49         [PT_LAR << 2]           = REG_LAR,
  50         [PT_LIR << 2]           = REG_LIR,
  51         [PT_MDR << 2]           = REG_MDR,
  52         [PT_A1 << 2]            = REG_A1,
  53         [PT_A0 << 2]            = REG_A0,
  54         [PT_D1 << 2]            = REG_D1,
  55         [PT_D0 << 2]            = REG_D0,
  56         [PT_ORIG_D0 << 2]       = REG_ORIG_D0,
  57         [PT_EPSW << 2]          = REG_EPSW,
  58         [PT_PC << 2]            = REG_PC,
  59 };
  60
  61 static inline int get_stack_long(struct task_struct *task, int offset)
  62 {
  63         return *(unsigned long *)
  64                 ((unsigned long) task->thread.uregs + offset);
  65 }
  66
  67 /*
  68  * this routine will put a word on the processes privileged stack.
  69  * the offset is how far from the base addr as stored in the TSS.
  70  * this routine assumes that all the privileged stacks are in our
  71  * data space.
  72  */
  73 static inline
  74 int put_stack_long(struct task_struct *task, int offset, unsigned long data)
  75 {
  76         unsigned long stack;
  77
  78         stack = (unsigned long) task->thread.uregs + offset;
  79         *(unsigned long *) stack = data;
  80         return 0;
  81 }
  82
  83 static inline unsigned long get_fpregs(struct fpu_state_struct *buf,
  84                                        struct task_struct *tsk)
  85 {
  86         return __copy_to_user(buf, &tsk->thread.fpu_state,
  87                               sizeof(struct fpu_state_struct));
  88 }
  89
  90 static inline unsigned long set_fpregs(struct task_struct *tsk,
  91                                        struct fpu_state_struct *buf)
  92 {
  93         return __copy_from_user(&tsk->thread.fpu_state, buf,
  94                                 sizeof(struct fpu_state_struct));
  95 }
  96
  97 static inline void fpsave_init(struct task_struct *task)
  98 {
  99         memset(&task->thread.fpu_state, 0, sizeof(struct fpu_state_struct));
 100 }
 101
 102 /*
 103  * make sure the single step bit is not set
 104  */
 105 void ptrace_disable(struct task_struct *child)
 106 {
 107 #ifndef CONFIG_MN10300_USING_JTAG
 108         struct user *dummy = NULL;
 109         long tmp;
 110
 111         tmp = get_stack_long(child, (unsigned long) &dummy->regs.epsw);
 112         tmp &= ~EPSW_T;
 113         put_stack_long(child, (unsigned long) &dummy->regs.epsw, tmp);
 114 #endif
 115 }
 116
 117 /*
 118  * set the single step bit
 119  */
 120 void ptrace_enable(struct task_struct *child)
 121 {
 122 #ifndef CONFIG_MN10300_USING_JTAG
 123         struct user *dummy = NULL;
 124         long tmp;
 125
 126         tmp = get_stack_long(child, (unsigned long) &dummy->regs.epsw);
 127         tmp |= EPSW_T;
 128         put_stack_long(child, (unsigned long) &dummy->regs.epsw, tmp);
 129 #endif
 130 }
 131
 132 /*
 133  * handle the arch-specific side of process tracing
 134  */
 135 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 136 {
 137         struct fpu_state_struct fpu_state;
 138         int i, ret;
 139
 140         switch (request) {
 141         /* read the word at location addr. */
 142         case PTRACE_PEEKTEXT: {
 143                 unsigned long tmp;
 144                 int copied;
 145
 146                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 147                 ret = -EIO;
 148                 if (copied != sizeof(tmp))
 149                         break;
 150                 ret = put_user(tmp, (unsigned long *) data);
 151                 break;
 152         }
 153
 154         /* read the word at location addr. */
 155         case PTRACE_PEEKDATA: {
 156                 unsigned long tmp;
 157                 int copied;
 158
 159                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 160                 ret = -EIO;
 161                 if (copied != sizeof(tmp))
 162                         break;
 163                 ret = put_user(tmp, (unsigned long *) data);
 164                 break;
 165         }
 166
 167         /* read the word at location addr in the USER area. */
 168         case PTRACE_PEEKUSR: {
 169                 unsigned long tmp;
 170
 171                 ret = -EIO;
 172                 if ((addr & 3) || addr < 0 ||
 173                     addr > sizeof(struct user) - 3)
 174                         break;
 175
 176                 tmp = 0;  /* Default return condition */
 177                 if (addr < NR_PTREGS << 2)
 178                         tmp = get_stack_long(child,
 179                                              ptrace_regid_to_frame[addr]);
 180                 ret = put_user(tmp, (unsigned long *) data);
 181                 break;
 182         }
 183
 184         /* write the word at location addr. */
 185         case PTRACE_POKETEXT:
 186         case PTRACE_POKEDATA:
 187                 if (access_process_vm(child, addr, &data, sizeof(data), 1) ==
 188                     sizeof(data))
 189                         ret = 0;
 190                 else
 191                         ret = -EIO;
 192                 break;
 193
 194                 /* write the word at location addr in the USER area */
 195         case PTRACE_POKEUSR:
 196                 ret = -EIO;
 197                 if ((addr & 3) || addr < 0 ||
 198                     addr > sizeof(struct user) - 3)
 199                         break;
 200
 201                 ret = 0;
 202                 if (addr < NR_PTREGS << 2)
 203                         ret = put_stack_long(child, ptrace_regid_to_frame[addr],
 204                                              data);
 205                 break;
 206
 207                 /* continue and stop at next (return from) syscall */
 208         case PTRACE_SYSCALL:
 209                 /* restart after signal. */
 210         case PTRACE_CONT:
 211                 ret = -EIO;
 212                 if ((unsigned long) data > _NSIG)
 213                         break;
 214                 if (request == PTRACE_SYSCALL)
 215                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 216                 else
 217                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 218                 child->exit_code = data;
 219                 ptrace_disable(child);
 220                 wake_up_process(child);
 221                 ret = 0;
 222                 break;
 223
 224                 /*
 225                  * make the child exit
 226                  * - the best I can do is send it a sigkill
 227                  * - perhaps it should be put in the status that it wants to
 228                  *   exit
 229                  */
 230         case PTRACE_KILL:
 231                 ret = 0;
 232                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 233                         break;
 234                 child->exit_code = SIGKILL;
 235                 clear_tsk_thread_flag(child, TIF_SINGLESTEP);
 236                 ptrace_disable(child);
 237                 wake_up_process(child);
 238                 break;
 239
 240         case PTRACE_SINGLESTEP: /* set the trap flag. */
 241 #ifndef CONFIG_MN10300_USING_JTAG
 242                 ret = -EIO;
 243                 if ((unsigned long) data > _NSIG)
 244                         break;
 245                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 246                 ptrace_enable(child);
 247                 child->exit_code = data;
 248                 wake_up_process(child);
 249                 ret = 0;
 250 #else
 251                 ret = -EINVAL;
 252 #endif
 253                 break;
 254
 255         case PTRACE_DETACH:     /* detach a process that was attached. */
 256                 ret = ptrace_detach(child, data);
 257                 break;
 258
 259                 /* Get all gp regs from the child. */
 260         case PTRACE_GETREGS: {
 261                 unsigned long tmp;
 262
 263                 if (!access_ok(VERIFY_WRITE, (unsigned *) data, NR_PTREGS << 2)) {
 264                         ret = -EIO;
 265                         break;
 266                 }
 267
 268                 for (i = 0; i < NR_PTREGS << 2; i += 4) {
 269                         tmp = get_stack_long(child, ptrace_regid_to_frame[i]);
 270                         __put_user(tmp, (unsigned long *) data);
 271                         data += sizeof(tmp);
 272                 }
 273                 ret = 0;
 274                 break;
 275         }
 276
 277         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 278                 unsigned long tmp;
 279
 280                 if (!access_ok(VERIFY_READ, (unsigned long *)data,
 281                                sizeof(struct pt_regs))) {
 282                         ret = -EIO;
 283                         break;
 284                 }
 285
 286                 for (i = 0; i < NR_PTREGS << 2; i += 4) {
 287                         __get_user(tmp, (unsigned long *) data);
 288                         put_stack_long(child, ptrace_regid_to_frame[i], tmp);
 289                         data += sizeof(tmp);
 290                 }
 291                 ret = 0;
 292                 break;
 293         }
 294
 295         case PTRACE_GETFPREGS: { /* Get the child FPU state. */
 296                 if (is_using_fpu(child)) {
 297                         unlazy_fpu(child);
 298                         fpu_state = child->thread.fpu_state;
 299                 } else {
 300                         memset(&fpu_state, 0, sizeof(fpu_state));
 301                 }
 302
 303                 ret = -EIO;
 304                 if (copy_to_user((void *) data, &fpu_state,
 305                                  sizeof(fpu_state)) == 0)
 306                         ret = 0;
 307                 break;
 308         }
 309
 310         case PTRACE_SETFPREGS: { /* Set the child FPU state. */
 311                 ret = -EFAULT;
 312                 if (copy_from_user(&fpu_state, (const void *) data,
 313                                    sizeof(fpu_state)) == 0) {
 314                         fpu_kill_state(child);
 315                         child->thread.fpu_state = fpu_state;
 316                         set_using_fpu(child);
 317                         ret = 0;
 318                 }
 319                 break;
 320         }
 321
 322         case PTRACE_SETOPTIONS: {
 323                 if (data & PTRACE_O_TRACESYSGOOD)
 324                         child->ptrace |= PT_TRACESYSGOOD;
 325                 else
 326                         child->ptrace &= ~PT_TRACESYSGOOD;
 327                 ret = 0;
 328                 break;
 329         }
 330
 331         default:
 332                 ret = -EIO;
 333                 break;
 334         }
 335
 336         return ret;
 337 }
 338
 339 /*
 340  * notification of system call entry/exit
 341  * - triggered by current->work.syscall_trace
 342  */
 343 asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit)
 344 {
 345 #if 0
 346         /* just in case... */
 347         printk(KERN_DEBUG "[%d] syscall_%lu(%lx,%lx,%lx,%lx) = %lx\n",
 348                current->pid,
 349                regs->orig_d0,
 350                regs->a0,
 351                regs->d1,
 352                regs->a3,
 353                regs->a2,
 354                regs->d0);
 355         return;
 356 #endif
 357
 358         if (!test_thread_flag(TIF_SYSCALL_TRACE) &&
 359             !test_thread_flag(TIF_SINGLESTEP))
 360                 return;
 361         if (!(current->ptrace & PT_PTRACED))
 362                 return;
 363
 364         /* the 0x80 provides a way for the tracing parent to distinguish
 365            between a syscall stop and SIGTRAP delivery */
 366         ptrace_notify(SIGTRAP |
 367                       ((current->ptrace & PT_TRACESYSGOOD) &&
 368                        !test_thread_flag(TIF_SINGLESTEP) ? 0x80 : 0));
 369
 370         /*
 371          * this isn't the same as continuing with a signal, but it will do
 372          * for normal use.  strace only continues with a signal if the
 373          * stopping signal is not SIGTRAP.  -brl
 374          */
 375         if (current->exit_code) {
 376                 send_sig(current->exit_code, current, 1);
 377                 current->exit_code = 0;
 378         }
 379 }