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        clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
  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                         ret = generic_ptrace_peekdata(child, addr, data);
  89                         break;
  90
  91                 /* Read the word at location address in the USER area. */
  92                 case PTRACE_PEEKUSR: {
  93                         unsigned long tmp;
  94
  95                         ret = -EIO;
  96                         if ((addr & 3) || addr < 0 || addr > PT_MAX << 2)
  97                                 break;
  98
  99                         tmp = get_reg(child, addr >> 2);
 100                         ret = put_user(tmp, datap);
 101                         break;
 102                 }
 103
 104                 /* Write the word at location address. */
 105                 case PTRACE_POKETEXT:
 106                 case PTRACE_POKEDATA:
 107                         ret = generic_ptrace_pokedata(child, addr, data);
 108                         break;
 109
 110                 /* Write the word at location address in the USER area. */
 111                 case PTRACE_POKEUSR:
 112                         ret = -EIO;
 113                         if ((addr & 3) || addr < 0 || addr > PT_MAX << 2)
 114                                 break;
 115
 116                         addr >>= 2;
 117
 118                         if (addr == PT_DCCR) {
 119                                 /* don't allow the tracing process to change stuff like
 120                                  * interrupt enable, kernel/user bit, dma enables etc.
 121                                  */
 122                                 data &= DCCR_MASK;
 123                                 data |= get_reg(child, PT_DCCR) & ~DCCR_MASK;
 124                         }
 125                         if (put_reg(child, addr, data))
 126                                 break;
 127                         ret = 0;
 128                         break;
 129
 130                 case PTRACE_SYSCALL:
 131                 case PTRACE_CONT:
 132                         ret = -EIO;
 133
 134                         if (!valid_signal(data))
 135                                 break;
 136
 137                         if (request == PTRACE_SYSCALL) {
 138                                 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 139                         }
 140                         else {
 141                                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 142                         }
 143
 144                         child->exit_code = data;
 145
 146                         /* TODO: make sure any pending breakpoint is killed */
 147                         wake_up_process(child);
 148                         ret = 0;
 149
 150                         break;
 151
 152                 /* Make the child exit by sending it a sigkill. */
 153                 case PTRACE_KILL:
 154                         ret = 0;
 155
 156                         if (child->exit_state == EXIT_ZOMBIE)
 157                                 break;
 158
 159                         child->exit_code = SIGKILL;
 160
 161                         /* TODO: make sure any pending breakpoint is killed */
 162                         wake_up_process(child);
 163                         break;
 164
 165                 /* Set the trap flag. */
 166                 case PTRACE_SINGLESTEP:
 167                         ret = -EIO;
 168
 169                         if (!valid_signal(data))
 170                                 break;
 171
 172                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 173
 174                         /* TODO: set some clever breakpoint mechanism... */
 175
 176                         child->exit_code = data;
 177                         wake_up_process(child);
 178                         ret = 0;
 179                         break;
 180
 181                 /* Get all GP registers from the child. */
 182                 case PTRACE_GETREGS: {
 183                         int i;
 184                         unsigned long tmp;
 185
 186                         ret = 0;
 187                         for (i = 0; i <= PT_MAX; i++) {
 188                                 tmp = get_reg(child, i);
 189
 190                                 if (put_user(tmp, datap)) {
 191                                         ret = -EFAULT;
 192                                         break;
 193                                 }
 194
 195                                 data += sizeof(long);
 196                         }
 197
 198                         break;
 199                 }
 200
 201                 /* Set all GP registers in the child. */
 202                 case PTRACE_SETREGS: {
 203                         int i;
 204                         unsigned long tmp;
 205
 206                         ret = 0;
 207                         for (i = 0; i <= PT_MAX; i++) {
 208                                 if (get_user(tmp, datap)) {
 209                                         ret = -EFAULT;
 210                                         break;
 211                                 }
 212
 213                                 if (i == PT_DCCR) {
 214                                         tmp &= DCCR_MASK;
 215                                         tmp |= get_reg(child, PT_DCCR) & ~DCCR_MASK;
 216                                 }
 217
 218                                 put_reg(child, i, tmp);
 219                                 data += sizeof(long);
 220                         }
 221
 222                         break;
 223                 }
 224
 225                 default:
 226                         ret = ptrace_request(child, request, addr, data);
 227                         break;
 228         }
 229
 230         return ret;
 231 }
 232
 233 void do_syscall_trace(void)
 234 {
 235         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 236                 return;
 237
 238         if (!(current->ptrace & PT_PTRACED))
 239                 return;
 240
 241         /* the 0x80 provides a way for the tracing parent to distinguish
 242            between a syscall stop and SIGTRAP delivery */
 243         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 244                                  ? 0x80 : 0));
 245
 246         /*
 247          * This isn't the same as continuing with a signal, but it will do for
 248          * normal use.
 249          */
 250         if (current->exit_code) {
 251                 send_sig(current->exit_code, current, 1);
 252                 current->exit_code = 0;
 253         }
 254 }