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