arch/m68k/kernel/ptrace.c

   1 /*
   2  *  linux/arch/m68k/kernel/ptrace.c
   3  *
   4  *  Copyright (C) 1994 by Hamish Macdonald
   5  *  Taken from linux/kernel/ptrace.c and modified for M680x0.
   6  *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
   7  *
   8  * This file is subject to the terms and conditions of the GNU General
   9  * Public License.  See the file COPYING in the main directory of
  10  * this archive for more details.
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/mm.h>
  16 #include <linux/smp.h>
  17 #include <linux/smp_lock.h>
  18 #include <linux/errno.h>
  19 #include <linux/ptrace.h>
  20 #include <linux/user.h>
  21 #include <linux/signal.h>
  22
  23 #include <asm/uaccess.h>
  24 #include <asm/page.h>
  25 #include <asm/pgtable.h>
  26 #include <asm/system.h>
  27 #include <asm/processor.h>
  28
  29 /*
  30  * does not yet catch signals sent when the child dies.
  31  * in exit.c or in signal.c.
  32  */
  33
  34 /* determines which bits in the SR the user has access to. */
  35 /* 1 = access 0 = no access */
  36 #define SR_MASK 0x001f
  37
  38 /* sets the trace bits. */
  39 #define TRACE_BITS 0x8000
  40
  41 /* Find the stack offset for a register, relative to thread.esp0. */
  42 #define PT_REG(reg)     ((long)&((struct pt_regs *)0)->reg)
  43 #define SW_REG(reg)     ((long)&((struct switch_stack *)0)->reg \
  44                          - sizeof(struct switch_stack))
  45 /* Mapping from PT_xxx to the stack offset at which the register is
  46    saved.  Notice that usp has no stack-slot and needs to be treated
  47    specially (see get_reg/put_reg below). */
  48 static int regoff[] = {
  49         [0]     = PT_REG(d1),
  50         [1]     = PT_REG(d2),
  51         [2]     = PT_REG(d3),
  52         [3]     = PT_REG(d4),
  53         [4]     = PT_REG(d5),
  54         [5]     = SW_REG(d6),
  55         [6]     = SW_REG(d7),
  56         [7]     = PT_REG(a0),
  57         [8]     = PT_REG(a1),
  58         [9]     = PT_REG(a2),
  59         [10]    = SW_REG(a3),
  60         [11]    = SW_REG(a4),
  61         [12]    = SW_REG(a5),
  62         [13]    = SW_REG(a6),
  63         [14]    = PT_REG(d0),
  64         [15]    = -1,
  65         [16]    = PT_REG(orig_d0),
  66         [17]    = PT_REG(sr),
  67         [18]    = PT_REG(pc),
  68 };
  69
  70 /*
  71  * Get contents of register REGNO in task TASK.
  72  */
  73 static inline long get_reg(struct task_struct *task, int regno)
  74 {
  75         unsigned long *addr;
  76
  77         if (regno == PT_USP)
  78                 addr = &task->thread.usp;
  79         else if (regno < sizeof(regoff)/sizeof(regoff[0]))
  80                 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
  81         else
  82                 return 0;
  83         return *addr;
  84 }
  85
  86 /*
  87  * Write contents of register REGNO in task TASK.
  88  */
  89 static inline int put_reg(struct task_struct *task, int regno,
  90                           unsigned long data)
  91 {
  92         unsigned long *addr;
  93
  94         if (regno == PT_USP)
  95                 addr = &task->thread.usp;
  96         else if (regno < sizeof(regoff)/sizeof(regoff[0]))
  97                 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
  98         else
  99                 return -1;
 100         *addr = data;
 101         return 0;
 102 }
 103
 104 /*
 105  * Make sure the single step bit is not set.
 106  */
 107 static inline void singlestep_disable(struct task_struct *child)
 108 {
 109         unsigned long tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 110         put_reg(child, PT_SR, tmp);
 111         clear_tsk_thread_flag(child, TIF_DELAYED_TRACE);
 112 }
 113
 114 /*
 115  * Called by kernel/ptrace.c when detaching..
 116  */
 117 void ptrace_disable(struct task_struct *child)
 118 {
 119         singlestep_disable(child);
 120         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 121 }
 122
 123 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 124 {
 125         unsigned long tmp;
 126         int i, ret = 0;
 127
 128         switch (request) {
 129         /* when I and D space are separate, these will need to be fixed. */
 130         case PTRACE_PEEKTEXT:   /* read word at location addr. */
 131         case PTRACE_PEEKDATA:
 132                 i = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 133                 if (i != sizeof(tmp))
 134                         goto out_eio;
 135                 ret = put_user(tmp, (unsigned long *)data);
 136                 break;
 137
 138         /* read the word at location addr in the USER area. */
 139         case PTRACE_PEEKUSR:
 140                 if (addr & 3)
 141                         goto out_eio;
 142                 addr >>= 2;     /* temporary hack. */
 143
 144                 if (addr >= 0 && addr < 19) {
 145                         tmp = get_reg(child, addr);
 146                         if (addr == PT_SR)
 147                                 tmp >>= 16;
 148                 } else if (addr >= 21 && addr < 49) {
 149                         tmp = child->thread.fp[addr - 21];
 150                         /* Convert internal fpu reg representation
 151                          * into long double format
 152                          */
 153                         if (FPU_IS_EMU && (addr < 45) && !(addr % 3))
 154                                 tmp = ((tmp & 0xffff0000) << 15) |
 155                                       ((tmp & 0x0000ffff) << 16);
 156                 } else
 157                         break;
 158                 ret = put_user(tmp, (unsigned long *)data);
 159                 break;
 160
 161         /* when I and D space are separate, this will have to be fixed. */
 162         case PTRACE_POKETEXT:   /* write the word at location addr. */
 163         case PTRACE_POKEDATA:
 164                 if (access_process_vm(child, addr, &data, sizeof(data), 1) != sizeof(data))
 165                         goto out_eio;
 166                 break;
 167
 168         case PTRACE_POKEUSR:    /* write the word at location addr in the USER area */
 169                 if (addr & 3)
 170                         goto out_eio;
 171                 addr >>= 2;     /* temporary hack. */
 172
 173                 if (addr == PT_SR) {
 174                         data &= SR_MASK;
 175                         data <<= 16;
 176                         data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 177                 } else if (addr >= 0 && addr < 19) {
 178                         if (put_reg(child, addr, data))
 179                                 goto out_eio;
 180                 } else if (addr >= 21 && addr < 48) {
 181                         /* Convert long double format
 182                          * into internal fpu reg representation
 183                          */
 184                         if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) {
 185                                 data = (unsigned long)data << 15;
 186                                 data = (data & 0xffff0000) |
 187                                        ((data & 0x0000ffff) >> 1);
 188                         }
 189                         child->thread.fp[addr - 21] = data;
 190                 } else
 191                         goto out_eio;
 192                 break;
 193
 194         case PTRACE_SYSCALL:    /* continue and stop at next (return from) syscall */
 195         case PTRACE_CONT:       /* restart after signal. */
 196                 if (!valid_signal(data))
 197                         goto out_eio;
 198
 199                 if (request == PTRACE_SYSCALL)
 200                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 201                 else
 202                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 203                 child->exit_code = data;
 204                 singlestep_disable(child);
 205                 wake_up_process(child);
 206                 break;
 207
 208         /*
 209          * make the child exit.  Best I can do is send it a sigkill.
 210          * perhaps it should be put in the status that it wants to
 211          * exit.
 212          */
 213         case PTRACE_KILL:
 214                 if (child->exit_state == EXIT_ZOMBIE) /* already dead */
 215                         break;
 216                 child->exit_code = SIGKILL;
 217                 singlestep_disable(child);
 218                 wake_up_process(child);
 219                 break;
 220
 221         case PTRACE_SINGLESTEP: /* set the trap flag. */
 222                 if (!valid_signal(data))
 223                         goto out_eio;
 224
 225                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 226                 tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
 227                 put_reg(child, PT_SR, tmp);
 228                 set_tsk_thread_flag(child, TIF_DELAYED_TRACE);
 229
 230                 child->exit_code = data;
 231                 /* give it a chance to run. */
 232                 wake_up_process(child);
 233                 break;
 234
 235         case PTRACE_DETACH:     /* detach a process that was attached. */
 236                 ret = ptrace_detach(child, data);
 237                 break;
 238
 239         case PTRACE_GETREGS:    /* Get all gp regs from the child. */
 240                 for (i = 0; i < 19; i++) {
 241                         tmp = get_reg(child, i);
 242                         if (i == PT_SR)
 243                                 tmp >>= 16;
 244                         ret = put_user(tmp, (unsigned long *)data);
 245                         if (ret)
 246                                 break;
 247                         data += sizeof(long);
 248                 }
 249                 break;
 250
 251         case PTRACE_SETREGS:    /* Set all gp regs in the child. */
 252                 for (i = 0; i < 19; i++) {
 253                         ret = get_user(tmp, (unsigned long *)data);
 254                         if (ret)
 255                                 break;
 256                         if (i == PT_SR) {
 257                                 tmp &= SR_MASK;
 258                                 tmp <<= 16;
 259                                 tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 260                         }
 261                         put_reg(child, i, tmp);
 262                         data += sizeof(long);
 263                 }
 264                 break;
 265
 266         case PTRACE_GETFPREGS:  /* Get the child FPU state. */
 267                 if (copy_to_user((void *)data, &child->thread.fp,
 268                                  sizeof(struct user_m68kfp_struct)))
 269                         ret = -EFAULT;
 270                 break;
 271
 272         case PTRACE_SETFPREGS:  /* Set the child FPU state. */
 273                 if (copy_from_user(&child->thread.fp, (void *)data,
 274                                    sizeof(struct user_m68kfp_struct)))
 275                         ret = -EFAULT;
 276                 break;
 277
 278         default:
 279                 ret = ptrace_request(child, request, addr, data);
 280                 break;
 281         }
 282
 283         return ret;
 284 out_eio:
 285         return -EIO;
 286 }
 287
 288 asmlinkage void syscall_trace(void)
 289 {
 290         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 291                                  ? 0x80 : 0));
 292         /*
 293          * this isn't the same as continuing with a signal, but it will do
 294          * for normal use.  strace only continues with a signal if the
 295          * stopping signal is not SIGTRAP.  -brl
 296          */
 297         if (current->exit_code) {
 298                 send_sig(current->exit_code, current, 1);
 299                 current->exit_code = 0;
 300         }
 301 }