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 #define SW_REG(reg)     ((long)&((struct switch_stack *)0)->reg \
  50                          - sizeof(struct switch_stack))
  51 /* Mapping from PT_xxx to the stack offset at which the register is
  52    saved.  Notice that usp has no stack-slot and needs to be treated
  53    specially (see get_reg/put_reg below). */
  54 static const int regoff[] = {
  55         PT_REG(er1), PT_REG(er2), PT_REG(er3), SW_REG(er4),
  56         SW_REG(er5), SW_REG(er6), PT_REG(er0), PT_REG(orig_er0),
  57         PT_REG(ccr), PT_REG(pc)
  58 };
  59
  60 /*
  61  * Get contents of register REGNO in task TASK.
  62  */
  63 static inline long get_reg(struct task_struct *task, int regno)
  64 {
  65         unsigned long *addr;
  66
  67         if (regno == PT_USP)
  68                 addr = &task->thread.usp;
  69         else if (regno < sizeof(regoff)/sizeof(regoff[0]))
  70                 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
  71         else
  72                 return 0;
  73         return *addr;
  74 }
  75
  76 /*
  77  * Write contents of register REGNO in task TASK.
  78  */
  79 static inline int put_reg(struct task_struct *task, int regno,
  80                           unsigned long data)
  81 {
  82         unsigned long *addr;
  83
  84         if (regno == PT_USP)
  85                 addr = &task->thread.usp;
  86         else if (regno < sizeof(regoff)/sizeof(regoff[0]))
  87                 addr = (unsigned long *) (task->thread.esp0 + regoff[regno]);
  88         else
  89                 return -1;
  90         *addr = data;
  91         return 0;
  92 }
  93
  94 /*
  95  * Called by kernel/ptrace.c when detaching..
  96  *
  97  * Make sure the single step bit is not set.
  98  */
  99 int ptrace_cancel_bpt(struct task_struct *child)
 100 {
 101         int i,r=0;
 102
 103         for(i=0; i<4; i++) {
 104                 if (child->thread.debugreg[i]) {
 105                         if (child->thread.debugreg[i] != ~0)
 106                                 put_user(child->thread.debugreg[i+4],
 107                                          (unsigned short *)child->thread.debugreg[i]);
 108                         r = 1;
 109                         child->thread.debugreg[i] = 0;
 110                 }
 111         }
 112         return r;
 113 }
 114
 115 const static unsigned char opcode0[]={
 116   0x04,0x02,0x04,0x02,0x04,0x02,0x04,0x02,  /* 0x58 */
 117   0x02,0x02,0x02,0x02,0x02,0x02,0x02,0x02,  /* 0x60 */
 118   0x02,0x02,0x11,0x11,0x02,0x02,0x04,0x04,  /* 0x68 */
 119   0x02,0x02,0x02,0x02,0x02,0x02,0x02,0x02,  /* 0x70 */
 120   0x08,0x04,0x06,0x04,0x04,0x04,0x04,0x04}; /* 0x78 */
 121
 122 const static int table_parser01(unsigned char *pc);
 123 const static int table_parser02(unsigned char *pc);
 124 const static int table_parser100(unsigned char *pc);
 125 const static int table_parser101(unsigned char *pc);
 126
 127 const static int (*parsers[])(unsigned char *pc)={table_parser01,table_parser02};
 128
 129 static int insn_length(unsigned char *pc)
 130 {
 131   if (*pc == 0x01)
 132     return table_parser01(pc+1);
 133   if (*pc < 0x58 || *pc>=0x80)
 134     return 2;
 135   else
 136     if (opcode0[*pc-0x58]<0x10)
 137       return opcode0[*pc-0x58];
 138     else
 139       return (*parsers[opcode0[*pc-0x58]-0x10])(pc+1);
 140 }
 141
 142 const static int table_parser01(unsigned char *pc)
 143 {
 144   const unsigned char codelen[]={0x10,0x00,0x00,0x00,0x11,0x00,0x00,0x00,
 145                                  0x02,0x00,0x00,0x00,0x04,0x04,0x00,0x04};
 146   const static int (*parsers[])(unsigned char *)={table_parser100,table_parser101};
 147   unsigned char second_index;
 148   second_index = (*pc) >> 4;
 149   if (codelen[second_index]<0x10)
 150     return codelen[second_index];
 151   else
 152     return parsers[codelen[second_index]-0x10](pc);
 153 }
 154
 155 const static int table_parser02(unsigned char *pc)
 156 {
 157   return (*pc & 0x20)?0x06:0x04;
 158 }
 159
 160 const static int table_parser100(unsigned char *pc)
 161 {
 162   return (*(pc+2) & 0x02)?0x08:0x06;
 163 }
 164
 165 const static int table_parser101(unsigned char *pc)
 166 {
 167   return (*(pc+2) & 0x02)?0x08:0x06;
 168 }
 169
 170 #define BREAK_INST 0x5730 /* TRAPA #3 */
 171
 172 int ptrace_set_bpt(struct task_struct *child)
 173 {
 174         unsigned long pc,next;
 175         unsigned short insn;
 176         pc = get_reg(child,PT_PC);
 177         next = insn_length((unsigned char *)pc) + pc;
 178         get_user(insn,(unsigned short *)pc);
 179         if (insn == 0x5470) {
 180                 /* rts */
 181                 unsigned long sp;
 182                 sp = get_reg(child,PT_USP);
 183                 get_user(next,(unsigned long *)sp);
 184         } else if ((insn & 0xfb00) != 0x5800) {
 185                 /* jmp / jsr */
 186                 int regs;
 187                 const short reg_tbl[]={PT_ER0,PT_ER1,PT_ER2,PT_ER3,
 188                                        PT_ER4,PT_ER5,PT_ER6,PT_USP};
 189                 switch(insn & 0xfb00) {
 190                         case 0x5900:
 191                                regs = (insn & 0x0070) >> 8;
 192                                next = get_reg(child,reg_tbl[regs]);
 193                                break;
 194                         case 0x5a00:
 195                                get_user(next,(unsigned long *)(pc+2));
 196                                next &= 0x00ffffff;
 197                                break;
 198                         case 0x5b00:
 199                                /* unneccessary? */
 200                                next = *(unsigned long *)(insn & 0xff);
 201                                break;
 202                 }
 203         } else if (((insn & 0xf000) == 0x4000) || ((insn &0xff00) == 0x5500)) {
 204                 /* b**:8 */
 205                 unsigned long dsp;
 206                 dsp = (long)(insn && 0xff)+pc+2;
 207                 child->thread.debugreg[1] = dsp;
 208                 get_user(child->thread.debugreg[5],(unsigned short *)dsp);
 209                 put_user(BREAK_INST,(unsigned short *)dsp);
 210         } else if (((insn & 0xff00) == 0x5800) || ((insn &0xff00) == 0x5c00)) {
 211                 /* b**:16 */
 212                 unsigned long dsp;
 213                 get_user(dsp,(unsigned short *)(pc+2));
 214                 dsp = (long)dsp+pc+4;
 215                 child->thread.debugreg[1] = dsp;
 216                 get_user(child->thread.debugreg[5],(unsigned short *)dsp);
 217                 put_user(BREAK_INST,(unsigned short *)dsp);
 218         }
 219         child->thread.debugreg[0] = next;
 220         get_user(child->thread.debugreg[4],(unsigned short *)next);
 221         put_user(BREAK_INST,(unsigned short *)next);
 222         return 0;
 223 }
 224
 225 inline
 226 static int read_long(struct task_struct * tsk, unsigned long addr,
 227         unsigned long * result)
 228 {
 229         *result = *(unsigned long *)addr;
 230         return 0;
 231 }
 232
 233 void ptrace_disable(struct task_struct *child)
 234 {
 235         ptrace_cancel_bpt(child);
 236 }
 237
 238 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
 239 {
 240         struct task_struct *child;
 241         int ret;
 242
 243         lock_kernel();
 244         ret = -EPERM;
 245         if (request == PTRACE_TRACEME) {
 246                 /* are we already being traced? */
 247                 if (current->ptrace & PT_PTRACED)
 248                         goto out;
 249                 /* set the ptrace bit in the process flags. */
 250                 current->ptrace |= PT_PTRACED;
 251                 ret = 0;
 252                 goto out;
 253         }
 254         ret = -ESRCH;
 255         read_lock(&tasklist_lock);
 256         child = find_task_by_pid(pid);
 257         if (child)
 258                 get_task_struct(child);
 259         read_unlock(&tasklist_lock);
 260         if (!child)
 261                 goto out;
 262
 263         ret = -EPERM;
 264         if (pid == 1)           /* you may not mess with init */
 265                 goto out_tsk;
 266
 267         if (request == PTRACE_ATTACH) {
 268                 ret = ptrace_attach(child);
 269                 goto out_tsk;
 270         }
 271         ret = -ESRCH;
 272         if (!(child->ptrace & PT_PTRACED))
 273                 goto out_tsk;
 274         if (child->state != TASK_STOPPED) {
 275                 if (request != PTRACE_KILL)
 276                         goto out_tsk;
 277         }
 278         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 279         if (ret < 0)
 280                 goto out_tsk;
 281
 282         switch (request) {
 283                 case PTRACE_PEEKTEXT: /* read word at location addr. */
 284                 case PTRACE_PEEKDATA: {
 285                         unsigned long tmp;
 286
 287                         ret = read_long(child, addr, &tmp);
 288                         if (ret < 0)
 289                                 break ;
 290                         ret = verify_area(VERIFY_WRITE, (void *) data, sizeof(long));
 291                         if (!ret)
 292                                 put_user(tmp, (unsigned long *) data);
 293                         break ;
 294                 }
 295
 296         /* read the word at location addr in the USER area. */
 297                 case PTRACE_PEEKUSR: {
 298                         unsigned long tmp;
 299
 300                         if ((addr & 3) || addr < 0 || addr >= sizeof(struct user))
 301                                 ret = -EIO;
 302
 303                         ret = verify_area(VERIFY_WRITE, (void *) data,
 304                                           sizeof(long));
 305                         if (ret)
 306                                 break ;
 307                         tmp = 0;  /* Default return condition */
 308                         addr = addr >> 2; /* temporary hack. */
 309                         if (addr < 10)
 310                                 tmp = get_reg(child, addr);
 311                         else {
 312                                 ret = -EIO;
 313                                 break ;
 314                         }
 315                         put_user(tmp,(unsigned long *) data);
 316                         ret = 0;
 317                         break ;
 318                 }
 319
 320       /* when 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                 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 330                         if ((addr & 3) || addr < 0 || addr >= sizeof(struct user)) {
 331                                 ret = -EIO;
 332                                 break ;
 333                         }
 334                         addr = addr >> 2; /* temporary hack. */
 335
 336                         if (addr == PT_ORIG_ER0) {
 337                                 ret = -EIO;
 338                                 break ;
 339                         }
 340                         if (addr == PT_CCR) {
 341                                 data &= SR_MASK;
 342                         }
 343                         if (addr < 10) {
 344                                 if (put_reg(child, addr, data))
 345                                         ret = -EIO;
 346                                 else
 347                                         ret = 0;
 348                                 break ;
 349                         }
 350                         ret = -EIO;
 351                         break ;
 352                 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 353                 case PTRACE_CONT: { /* restart after signal. */
 354                         ret = -EIO;
 355                         if ((unsigned long) data >= _NSIG)
 356                                 break ;
 357                         if (request == PTRACE_SYSCALL)
 358                                 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 359                         else
 360                                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 361                         child->exit_code = data;
 362                         wake_up_process(child);
 363                         /* make sure the single step bit is not set. */
 364                         ptrace_cancel_bpt(child);
 365                         ret = 0;
 366                 }
 367
 368 /*
 369  * make the child exit.  Best I can do is send it a sigkill.
 370  * perhaps it should be put in the status that it wants to
 371  * exit.
 372  */
 373                 case PTRACE_KILL: {
 374
 375                         ret = 0;
 376                         if (child->state == TASK_ZOMBIE) /* already dead */
 377                                 break;
 378                         child->exit_code = SIGKILL;
 379                         ptrace_cancel_bpt(child);
 380                         wake_up_process(child);
 381                         break;
 382                 }
 383
 384                 case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 385                         ret = -EIO;
 386                         if ((unsigned long) data > _NSIG)
 387                                 break;
 388                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 389                         child->thread.debugreg[0]=-1;
 390                         child->exit_code = data;
 391                         wake_up_process(child);
 392                         ret = 0;
 393                         break;
 394                 }
 395
 396                 case PTRACE_DETACH:     /* detach a process that was attached. */
 397                         ret = ptrace_detach(child, data);
 398                         break;
 399
 400                 case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 401                         int i;
 402                         unsigned long tmp;
 403                         for (i = 0; i < 19; i++) {
 404                             tmp = get_reg(child, i);
 405                             if (put_user(tmp, (unsigned long *) data)) {
 406                                 ret = -EFAULT;
 407                                 break;
 408                             }
 409                             data += sizeof(long);
 410                         }
 411                         ret = 0;
 412                         break;
 413                 }
 414
 415                 case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 416                         int i;
 417                         unsigned long tmp;
 418                         for (i = 0; i < 10; i++) {
 419                             if (get_user(tmp, (unsigned long *) data)) {
 420                                 ret = -EFAULT;
 421                                 break;
 422                             }
 423                             put_reg(child, i, tmp);
 424                             data += sizeof(long);
 425                         }
 426                         ret = 0;
 427                         break;
 428                 }
 429
 430                 default:
 431                         ret = -EIO;
 432                         break;
 433         }
 434 out_tsk:
 435         put_task_struct(child);
 436 out:
 437         unlock_kernel();
 438         return ret;
 439 }
 440
 441 asmlinkage void syscall_trace(void)
 442 {
 443         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 444                 return;
 445         if (!(current->ptrace & PT_PTRACED))
 446                 return;
 447         current->exit_code = SIGTRAP;
 448         current->state = TASK_STOPPED;
 449         notify_parent(current, SIGCHLD);
 450         schedule();
 451         /*
 452          * this isn't the same as continuing with a signal, but it will do
 453          * for normal use.  strace only continues with a signal if the
 454          * stopping signal is not SIGTRAP.  -brl
 455          */
 456         if (current->exit_code) {
 457                 send_sig(current->exit_code, current, 1);
 458                 current->exit_code = 0;
 459         }
 460 }
 461
 462 asmlinkage void trace_trap(unsigned long bp)
 463 {
 464         if (current->thread.debugreg[0] == bp ||
 465             current->thread.debugreg[1] == bp) {
 466                 ptrace_cancel_bpt(current);
 467                 force_sig(SIGTRAP,current);
 468         } else
 469                 force_sig(SIGILL,current);
 470 }