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