arch/h8300/kernel/ptrace.c

   1 /*
   2  *  linux/arch/h8300/kernel/ptrace.c
   3  *
   4  *  Yoshinori Sato <qzb04471@nifty.ne.jp>
   5  *
   6  *  Based on:
   7  *  linux/arch/m68k/kernel/ptrace.c
   8  *
   9  *  Copyright (C) 1994 by Hamish Macdonald
  10  *  Taken from linux/kernel/ptrace.c and modified for M680x0.
  11  *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
  12  *
  13  * This file is subject to the terms and conditions of the GNU General
  14  * Public License.  See the file COPYING in the main directory of
  15  * this archive for more details.
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/sched.h>
  20 #include <linux/mm.h>
  21 #include <linux/smp.h>
  22 #include <linux/smp_lock.h>
  23 #include <linux/errno.h>
  24 #include <linux/ptrace.h>
  25 #include <linux/user.h>
  26 #include <linux/config.h>
  27
  28 #include <asm/uaccess.h>
  29 #include <asm/page.h>
  30 #include <asm/pgtable.h>
  31 #include <asm/system.h>
  32 #include <asm/processor.h>
  33 #include <asm/signal.h>
  34
  35 /*
  36  * does not yet catch signals sent when the child dies.
  37  * in exit.c or in signal.c.
  38  */
  39
  40 /* determines which bits in the SR the user has access to. */
  41 /* 1 = access 0 = no access */
  42 #define SR_MASK 0x001f
  43
  44 /* sets the trace bits. */
  45 #define TRACE_BITS 0x8000
  46
  47 /* Find the stack offset for a register, relative to thread.esp0. */
  48 #define PT_REG(reg)     ((long)&((struct pt_regs *)0)->reg)
  49 /* Mapping from PT_xxx to the stack offset at which the register is
  50    saved.  Notice that usp has no stack-slot and needs to be treated
  51    specially (see get_reg/put_reg below). */
  52 static const int regoff[] = {
  53         PT_REG(er1), PT_REG(er2), PT_REG(er3), PT_REG(er4),
  54         PT_REG(er5), PT_REG(er6), PT_REG(er0), PT_REG(orig_er0),
  55         PT_REG(ccr), PT_REG(pc)
  56 };
  57
  58 /*
  59  * Get contents of register REGNO in task TASK.
  60  */
  61 static inline long get_reg(struct task_struct *task, int regno)
  62 {
  63         unsigned long *addr;
  64
  65         if (regno == PT_USP)
  66                 addr = &task->thread.usp;
  67         else if (regno < sizeof(regoff)/sizeof(regoff[0]))
  68                 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
  69         else
  70                 return 0;
  71         return *addr;
  72 }
  73
  74 /*
  75  * Write contents of register REGNO in task TASK.
  76  */
  77 static inline int put_reg(struct task_struct *task, int regno,
  78                           unsigned long data)
  79 {
  80         unsigned long *addr;
  81
  82         if (regno == PT_USP)
  83                 addr = &task->thread.usp;
  84         else if (regno < sizeof(regoff)/sizeof(regoff[0]))
  85                 addr = (unsigned long *) (task->thread.esp0 + regoff[regno]);
  86         else
  87                 return -1;
  88         *addr = data;
  89         return 0;
  90 }
  91
  92 /*
  93  * Called by kernel/ptrace.c when detaching..
  94  *
  95  * Make sure the single step bit is not set.
  96  */
  97 int ptrace_cancel_bpt(struct task_struct *child)
  98 {
  99         int i,r=0;
 100
 101         for(i=0; i<4; i++) {
 102                 if (child->thread.debugreg[i]) {
 103                         if (child->thread.debugreg[i] != ~0)
 104                                 put_user(child->thread.debugreg[i+4],
 105                                          (unsigned short *)child->thread.debugreg[i]);
 106                         r = 1;
 107                         child->thread.debugreg[i] = 0;
 108                 }
 109         }
 110         return r;
 111 }
 112
 113 const static unsigned char opcode0[]={
 114   0x04,0x02,0x04,0x02,0x04,0x02,0x04,0x02,  /* 0x58 */
 115   0x02,0x02,0x02,0x02,0x02,0x02,0x02,0x02,  /* 0x60 */
 116   0x02,0x02,0x11,0x11,0x02,0x02,0x04,0x04,  /* 0x68 */
 117   0x02,0x02,0x02,0x02,0x02,0x02,0x02,0x02,  /* 0x70 */
 118   0x08,0x04,0x06,0x04,0x04,0x04,0x04,0x04}; /* 0x78 */
 119
 120 const static int table_parser01(unsigned char *pc);
 121 const static int table_parser02(unsigned char *pc);
 122 const static int table_parser100(unsigned char *pc);
 123 const static int table_parser101(unsigned char *pc);
 124
 125 const static int (*parsers[])(unsigned char *pc)={table_parser01,table_parser02};
 126
 127 static int insn_length(unsigned char *pc)
 128 {
 129   if (*pc == 0x01)
 130     return table_parser01(pc+1);
 131   if (*pc < 0x58 || *pc>=0x80)
 132     return 2;
 133   else
 134     if (opcode0[*pc-0x58]<0x10)
 135       return opcode0[*pc-0x58];
 136     else
 137       return (*parsers[opcode0[*pc-0x58]-0x10])(pc+1);
 138 }
 139
 140 const static int table_parser01(unsigned char *pc)
 141 {
 142   const unsigned char codelen[]={0x10,0x00,0x00,0x00,0x11,0x00,0x00,0x00,
 143                                  0x02,0x00,0x00,0x00,0x04,0x04,0x00,0x04};
 144   const static int (*parsers[])(unsigned char *)={table_parser100,table_parser101};
 145   unsigned char second_index;
 146   second_index = (*pc) >> 4;
 147   if (codelen[second_index]<0x10)
 148     return codelen[second_index];
 149   else
 150     return parsers[codelen[second_index]-0x10](pc);
 151 }
 152
 153 const static int table_parser02(unsigned char *pc)
 154 {
 155   return (*pc & 0x20)?0x06:0x04;
 156 }
 157
 158 const static int table_parser100(unsigned char *pc)
 159 {
 160   return (*(pc+2) & 0x02)?0x08:0x06;
 161 }
 162
 163 const static int table_parser101(unsigned char *pc)
 164 {
 165   return (*(pc+2) & 0x02)?0x08:0x06;
 166 }
 167
 168 #define BREAK_INST 0x5730 /* TRAPA #3 */
 169
 170 int ptrace_set_bpt(struct task_struct *child)
 171 {
 172         unsigned long pc,next;
 173         unsigned short insn;
 174         pc = get_reg(child,PT_PC);
 175         next = insn_length((unsigned char *)pc) + pc;
 176         get_user(insn,(unsigned short *)pc);
 177         if (insn == 0x5470) {
 178                 /* rts */
 179                 unsigned long sp;
 180                 sp = get_reg(child,PT_USP);
 181                 get_user(next,(unsigned long *)sp);
 182         } else if ((insn & 0xfb00) != 0x5800) {
 183                 /* jmp / jsr */
 184                 int regs;
 185                 const short reg_tbl[]={PT_ER0,PT_ER1,PT_ER2,PT_ER3,
 186                                        PT_ER4,PT_ER5,PT_ER6,PT_USP};
 187                 switch(insn & 0xfb00) {
 188                         case 0x5900:
 189                                regs = (insn & 0x0070) >> 8;
 190                                next = get_reg(child,reg_tbl[regs]);
 191                                break;
 192                         case 0x5a00:
 193                                get_user(next,(unsigned long *)(pc+2));
 194                                next &= 0x00ffffff;
 195                                break;
 196                         case 0x5b00:
 197                                /* unneccessary? */
 198                                next = *(unsigned long *)(insn & 0xff);
 199                                break;
 200                 }
 201         } else if (((insn & 0xf000) == 0x4000) || ((insn &0xff00) == 0x5500)) {
 202                 /* b**:8 */
 203                 unsigned long dsp;
 204                 dsp = (long)(insn && 0xff)+pc+2;
 205                 child->thread.debugreg[1] = dsp;
 206                 get_user(child->thread.debugreg[5],(unsigned short *)dsp);
 207                 put_user(BREAK_INST,(unsigned short *)dsp);
 208         } else if (((insn & 0xff00) == 0x5800) || ((insn &0xff00) == 0x5c00)) {
 209                 /* b**:16 */
 210                 unsigned long dsp;
 211                 get_user(dsp,(unsigned short *)(pc+2));
 212                 dsp = (long)dsp+pc+4;
 213                 child->thread.debugreg[1] = dsp;
 214                 get_user(child->thread.debugreg[5],(unsigned short *)dsp);
 215                 put_user(BREAK_INST,(unsigned short *)dsp);
 216         }
 217         child->thread.debugreg[0] = next;
 218         get_user(child->thread.debugreg[4],(unsigned short *)next);
 219         put_user(BREAK_INST,(unsigned short *)next);
 220         return 0;
 221 }
 222
 223 inline
 224 static int read_long(struct task_struct * tsk, unsigned long addr,
 225         unsigned long * result)
 226 {
 227         *result = *(unsigned long *)addr;
 228         return 0;
 229 }
 230
 231 void ptrace_disable(struct task_struct *child)
 232 {
 233         ptrace_cancel_bpt(child);
 234 }
 235
 236 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
 237 {
 238         struct task_struct *child;
 239         int ret;
 240
 241         lock_kernel();
 242         ret = -EPERM;
 243         if (request == PTRACE_TRACEME) {
 244                 /* are we already being traced? */
 245                 if (current->ptrace & PT_PTRACED)
 246                         goto out;
 247                 /* set the ptrace bit in the process flags. */
 248                 current->ptrace |= PT_PTRACED;
 249                 ret = 0;
 250                 goto out;
 251         }
 252         ret = -ESRCH;
 253         read_lock(&tasklist_lock);
 254         child = find_task_by_pid(pid);
 255         if (child)
 256                 get_task_struct(child);
 257         read_unlock(&tasklist_lock);
 258         if (!child)
 259                 goto out;
 260
 261         ret = -EPERM;
 262         if (pid == 1)           /* you may not mess with init */
 263                 goto out_tsk;
 264
 265         if (request == PTRACE_ATTACH) {
 266                 ret = ptrace_attach(child);
 267                 goto out_tsk;
 268         }
 269         ret = -ESRCH;
 270         if (!(child->ptrace & PT_PTRACED))
 271                 goto out_tsk;
 272         if (child->state != TASK_STOPPED) {
 273                 if (request != PTRACE_KILL)
 274                         goto out_tsk;
 275         }
 276         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 277         if (ret < 0)
 278                 goto out_tsk;
 279
 280         switch (request) {
 281                 case PTRACE_PEEKTEXT: /* read word at location addr. */
 282                 case PTRACE_PEEKDATA: {
 283                         unsigned long tmp;
 284
 285                         ret = read_long(child, addr, &tmp);
 286                         if (ret < 0)
 287                                 break ;
 288                         ret = verify_area(VERIFY_WRITE, (void *) data, sizeof(long));
 289                         if (!ret)
 290                                 put_user(tmp, (unsigned long *) data);
 291                         break ;
 292                 }
 293
 294         /* read the word at location addr in the USER area. */
 295                 case PTRACE_PEEKUSR: {
 296                         unsigned long tmp;
 297
 298                         if ((addr & 3) || addr < 0 || addr >= sizeof(struct user))
 299                                 ret = -EIO;
 300
 301                         ret = verify_area(VERIFY_WRITE, (void *) data,
 302                                           sizeof(long));
 303                         if (ret)
 304                                 break ;
 305                         tmp = 0;  /* Default return condition */
 306                         addr = addr >> 2; /* temporary hack. */
 307                         if (addr < 10)
 308                                 tmp = get_reg(child, addr);
 309                         else {
 310                                 ret = -EIO;
 311                                 break ;
 312                         }
 313                         put_user(tmp,(unsigned long *) data);
 314                         ret = 0;
 315                         break ;
 316                 }
 317
 318       /* when I and D space are separate, this will have to be fixed. */
 319                 case PTRACE_POKETEXT: /* write the word at location addr. */
 320                 case PTRACE_POKEDATA:
 321                         ret = 0;
 322                         if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 323                                 break;
 324                         ret = -EIO;
 325                         break;
 326
 327                 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 328                         if ((addr & 3) || addr < 0 || addr >= sizeof(struct user)) {
 329                                 ret = -EIO;
 330                                 break ;
 331                         }
 332                         addr = addr >> 2; /* temporary hack. */
 333
 334                         if (addr == PT_ORIG_ER0) {
 335                                 ret = -EIO;
 336                                 break ;
 337                         }
 338                         if (addr == PT_CCR) {
 339                                 data &= SR_MASK;
 340                         }
 341                         if (addr < 10) {
 342                                 if (put_reg(child, addr, data))
 343                                         ret = -EIO;
 344                                 else
 345                                         ret = 0;
 346                                 break ;
 347                         }
 348                         ret = -EIO;
 349                         break ;
 350                 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 351                 case PTRACE_CONT: { /* restart after signal. */
 352                         ret = -EIO;
 353                         if ((unsigned long) data >= _NSIG)
 354                                 break ;
 355                         if (request == PTRACE_SYSCALL)
 356                                 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 357                         else
 358                                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 359                         child->exit_code = data;
 360                         wake_up_process(child);
 361                         /* make sure the single step bit is not set. */
 362                         ptrace_cancel_bpt(child);
 363                         ret = 0;
 364                 }
 365
 366 /*
 367  * make the child exit.  Best I can do is send it a sigkill.
 368  * perhaps it should be put in the status that it wants to
 369  * exit.
 370  */
 371                 case PTRACE_KILL: {
 372
 373                         ret = 0;
 374                         if (child->state == TASK_ZOMBIE) /* already dead */
 375                                 break;
 376                         child->exit_code = SIGKILL;
 377                         ptrace_cancel_bpt(child);
 378                         wake_up_process(child);
 379                         break;
 380                 }
 381
 382                 case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 383                         ret = -EIO;
 384                         if ((unsigned long) data > _NSIG)
 385                                 break;
 386                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 387                         child->thread.debugreg[0]=-1;
 388                         child->exit_code = data;
 389                         wake_up_process(child);
 390                         ret = 0;
 391                         break;
 392                 }
 393
 394                 case PTRACE_DETACH:     /* detach a process that was attached. */
 395                         ret = ptrace_detach(child, data);
 396                         break;
 397
 398                 case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 399                         int i;
 400                         unsigned long tmp;
 401                         for (i = 0; i < 19; i++) {
 402                             tmp = get_reg(child, i);
 403                             if (put_user(tmp, (unsigned long *) data)) {
 404                                 ret = -EFAULT;
 405                                 break;
 406                             }
 407                             data += sizeof(long);
 408                         }
 409                         ret = 0;
 410                         break;
 411                 }
 412
 413                 case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 414                         int i;
 415                         unsigned long tmp;
 416                         for (i = 0; i < 10; i++) {
 417                             if (get_user(tmp, (unsigned long *) data)) {
 418                                 ret = -EFAULT;
 419                                 break;
 420                             }
 421                             put_reg(child, i, tmp);
 422                             data += sizeof(long);
 423                         }
 424                         ret = 0;
 425                         break;
 426                 }
 427
 428                 default:
 429                         ret = -EIO;
 430                         break;
 431         }
 432 out_tsk:
 433         put_task_struct(child);
 434 out:
 435         unlock_kernel();
 436         return ret;
 437 }
 438
 439 asmlinkage void syscall_trace(void)
 440 {
 441         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 442                 return;
 443         if (!(current->ptrace & PT_PTRACED))
 444                 return;
 445         current->exit_code = SIGTRAP;
 446         current->state = TASK_STOPPED;
 447         notify_parent(current, SIGCHLD);
 448         schedule();
 449         /*
 450          * this isn't the same as continuing with a signal, but it will do
 451          * for normal use.  strace only continues with a signal if the
 452          * stopping signal is not SIGTRAP.  -brl
 453          */
 454         if (current->exit_code) {
 455                 send_sig(current->exit_code, current, 1);
 456                 current->exit_code = 0;
 457         }
 458 }
 459
 460 asmlinkage void trace_trap(unsigned long bp)
 461 {
 462         if (current->thread.debugreg[0] == bp ||
 463             current->thread.debugreg[1] == bp) {
 464                 ptrace_cancel_bpt(current);
 465                 force_sig(SIGTRAP,current);
 466         } else
 467                 force_sig(SIGILL,current);
 468 }