arch/cris/arch-v10/kernel/ptrace.c

   1 /*
   2  * Copyright (C) 2000-2003, Axis Communications AB.
   3  */
   4
   5 #include <linux/kernel.h>
   6 #include <linux/sched.h>
   7 #include <linux/mm.h>
   8 #include <linux/smp.h>
   9 #include <linux/smp_lock.h>
  10 #include <linux/errno.h>
  11 #include <linux/ptrace.h>
  12 #include <linux/user.h>
  13
  14 #include <asm/uaccess.h>
  15 #include <asm/page.h>
  16 #include <asm/pgtable.h>
  17 #include <asm/system.h>
  18 #include <asm/processor.h>
  19
  20 /*
  21  * Determines which bits in DCCR the user has access to.
  22  * 1 = access, 0 = no access.
  23  */
  24 #define DCCR_MASK 0x0000001f     /* XNZVC */
  25
  26 extern inline long get_reg(struct task_struct *, unsigned int);
  27 extern inline long put_reg(struct task_struct *, unsigned int, unsigned long);
  28
  29 /*
  30  * Called by kernel/ptrace.c when detaching.
  31  *
  32  * Make sure the single step bit is not set.
  33  */
  34 void
  35 ptrace_disable(struct task_struct *child)
  36 {
  37        /* Todo - pending singlesteps? */
  38 }
  39
  40 /*
  41  * Note that this implementation of ptrace behaves differently from vanilla
  42  * ptrace.  Contrary to what the man page says, in the PTRACE_PEEKTEXT,
  43  * PTRACE_PEEKDATA, and PTRACE_PEEKUSER requests the data variable is not
  44  * ignored.  Instead, the data variable is expected to point at a location
  45  * (in user space) where the result of the ptrace call is written (instead of
  46  * being returned).
  47  */
  48 asmlinkage int
  49 sys_ptrace(long request, long pid, long addr, long data)
  50 {
  51         struct task_struct *child;
  52         int ret;
  53
  54         lock_kernel();
  55         ret = -EPERM;
  56
  57         if (request == PTRACE_TRACEME) {
  58                 if (current->ptrace & PT_PTRACED)
  59                         goto out;
  60
  61                 current->ptrace |= PT_PTRACED;
  62                 ret = 0;
  63                 goto out;
  64         }
  65
  66         ret = -ESRCH;
  67         read_lock(&tasklist_lock);
  68         child = find_task_by_pid(pid);
  69
  70         if (child)
  71                 get_task_struct(child);
  72
  73         read_unlock(&tasklist_lock);
  74
  75         if (!child)
  76                 goto out;
  77
  78         ret = -EPERM;
  79
  80         if (pid == 1)           /* Leave the init process alone! */
  81                 goto out_tsk;
  82
  83         if (request == PTRACE_ATTACH) {
  84                 ret = ptrace_attach(child);
  85                 goto out_tsk;
  86         }
  87
  88         ret = ptrace_check_attach(child, request == PTRACE_KILL);
  89         if (ret < 0)
  90                 goto out_tsk;
  91
  92         switch (request) {
  93                 /* Read word at location address. */
  94                 case PTRACE_PEEKTEXT:
  95                 case PTRACE_PEEKDATA: {
  96                         unsigned long tmp;
  97                         int copied;
  98
  99                         copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 100                         ret = -EIO;
 101
 102                         if (copied != sizeof(tmp))
 103                                 break;
 104
 105                         ret = put_user(tmp,(unsigned long *) data);
 106                         break;
 107                 }
 108
 109                 /* Read the word at location address in the USER area. */
 110                 case PTRACE_PEEKUSR: {
 111                         unsigned long tmp;
 112
 113                         ret = -EIO;
 114                         if ((addr & 3) || addr < 0 || addr > PT_MAX << 2)
 115                                 break;
 116
 117                         tmp = get_reg(child, addr >> 2);
 118                         ret = put_user(tmp, (unsigned long *)data);
 119                         break;
 120                 }
 121
 122                 /* Write the word at location address. */
 123                 case PTRACE_POKETEXT:
 124                 case PTRACE_POKEDATA:
 125                         ret = 0;
 126
 127                         if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 128                                 break;
 129
 130                         ret = -EIO;
 131                         break;
 132
 133                 /* Write the word at location address in the USER area. */
 134                 case PTRACE_POKEUSR:
 135                         ret = -EIO;
 136                         if ((addr & 3) || addr < 0 || addr > PT_MAX << 2)
 137                                 break;
 138
 139                         addr >>= 2;
 140
 141                         if (addr == PT_DCCR) {
 142                                 /* don't allow the tracing process to change stuff like
 143                                  * interrupt enable, kernel/user bit, dma enables etc.
 144                                  */
 145                                 data &= DCCR_MASK;
 146                                 data |= get_reg(child, PT_DCCR) & ~DCCR_MASK;
 147                         }
 148                         if (put_reg(child, addr, data))
 149                                 break;
 150                         ret = 0;
 151                         break;
 152
 153                 case PTRACE_SYSCALL:
 154                 case PTRACE_CONT:
 155                         ret = -EIO;
 156
 157                         if ((unsigned long) data > _NSIG)
 158                                 break;
 159
 160                         if (request == PTRACE_SYSCALL) {
 161                                 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 162                         }
 163                         else {
 164                                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 165                         }
 166
 167                         child->exit_code = data;
 168
 169                         /* TODO: make sure any pending breakpoint is killed */
 170                         wake_up_process(child);
 171                         ret = 0;
 172
 173                         break;
 174
 175                 /* Make the child exit by sending it a sigkill. */
 176                 case PTRACE_KILL:
 177                         ret = 0;
 178
 179                         if (child->state == TASK_ZOMBIE)
 180                                 break;
 181
 182                         child->exit_code = SIGKILL;
 183
 184                         /* TODO: make sure any pending breakpoint is killed */
 185                         wake_up_process(child);
 186                         break;
 187
 188                 /* Set the trap flag. */
 189                 case PTRACE_SINGLESTEP:
 190                         ret = -EIO;
 191
 192                         if ((unsigned long) data > _NSIG)
 193                                 break;
 194
 195                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 196
 197                         /* TODO: set some clever breakpoint mechanism... */
 198
 199                         child->exit_code = data;
 200                         wake_up_process(child);
 201                         ret = 0;
 202                         break;
 203
 204                 case PTRACE_DETACH:
 205                         ret = ptrace_detach(child, data);
 206                         break;
 207
 208                 /* Get all GP registers from the child. */
 209                 case PTRACE_GETREGS: {
 210                         int i;
 211                         unsigned long tmp;
 212
 213                         for (i = 0; i <= PT_MAX; i++) {
 214                                 tmp = get_reg(child, i);
 215
 216                                 if (put_user(tmp, (unsigned long *) data)) {
 217                                         ret = -EFAULT;
 218                                         goto out_tsk;
 219                                 }
 220
 221                                 data += sizeof(long);
 222                         }
 223
 224                         ret = 0;
 225                         break;
 226                 }
 227
 228                 /* Set all GP registers in the child. */
 229                 case PTRACE_SETREGS: {
 230                         int i;
 231                         unsigned long tmp;
 232
 233                         for (i = 0; i <= PT_MAX; i++) {
 234                                 if (get_user(tmp, (unsigned long *) data)) {
 235                                         ret = -EFAULT;
 236                                         goto out_tsk;
 237                                 }
 238
 239                                 if (i == PT_DCCR) {
 240                                         tmp &= DCCR_MASK;
 241                                         tmp |= get_reg(child, PT_DCCR) & ~DCCR_MASK;
 242                                 }
 243
 244                                 put_reg(child, i, tmp);
 245                                 data += sizeof(long);
 246                         }
 247
 248                         ret = 0;
 249                         break;
 250                 }
 251
 252                 default:
 253                         ret = ptrace_request(child, request, addr, data);
 254                         break;
 255         }
 256 out_tsk:
 257         put_task_struct(child);
 258 out:
 259         unlock_kernel();
 260         return ret;
 261 }
 262
 263 void do_syscall_trace(void)
 264 {
 265         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 266                 return;
 267
 268         if (!(current->ptrace & PT_PTRACED))
 269                 return;
 270
 271         /* the 0x80 provides a way for the tracing parent to distinguish
 272            between a syscall stop and SIGTRAP delivery */
 273         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 274                                  ? 0x80 : 0));
 275
 276         /*
 277          * This isn't the same as continuing with a signal, but it will do for
 278          * normal use.
 279          */
 280         if (current->exit_code) {
 281                 send_sig(current->exit_code, current, 1);
 282                 current->exit_code = 0;
 283         }
 284 }