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                         unsigned long tmp;
  88                         int copied;
  89
  90                         copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
  91                         ret = -EIO;
  92
  93                         if (copied != sizeof(tmp))
  94                                 break;
  95
  96                         ret = put_user(tmp,datap);
  97                         break;
  98                 }
  99
 100                 /* Read the word at location address in the USER area. */
 101                 case PTRACE_PEEKUSR: {
 102                         unsigned long tmp;
 103
 104                         ret = -EIO;
 105                         if ((addr & 3) || addr < 0 || addr > PT_MAX << 2)
 106                                 break;
 107
 108                         tmp = get_reg(child, addr >> 2);
 109                         ret = put_user(tmp, datap);
 110                         break;
 111                 }
 112
 113                 /* Write the word at location address. */
 114                 case PTRACE_POKETEXT:
 115                 case PTRACE_POKEDATA:
 116                         ret = 0;
 117
 118                         if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 119                                 break;
 120
 121                         ret = -EIO;
 122                         break;
 123
 124                 /* Write the word at location address in the USER area. */
 125                 case PTRACE_POKEUSR:
 126                         ret = -EIO;
 127                         if ((addr & 3) || addr < 0 || addr > PT_MAX << 2)
 128                                 break;
 129
 130                         addr >>= 2;
 131
 132                         if (addr == PT_DCCR) {
 133                                 /* don't allow the tracing process to change stuff like
 134                                  * interrupt enable, kernel/user bit, dma enables etc.
 135                                  */
 136                                 data &= DCCR_MASK;
 137                                 data |= get_reg(child, PT_DCCR) & ~DCCR_MASK;
 138                         }
 139                         if (put_reg(child, addr, data))
 140                                 break;
 141                         ret = 0;
 142                         break;
 143
 144                 case PTRACE_SYSCALL:
 145                 case PTRACE_CONT:
 146                         ret = -EIO;
 147
 148                         if (!valid_signal(data))
 149                                 break;
 150
 151                         if (request == PTRACE_SYSCALL) {
 152                                 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 153                         }
 154                         else {
 155                                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 156                         }
 157
 158                         child->exit_code = data;
 159
 160                         /* TODO: make sure any pending breakpoint is killed */
 161                         wake_up_process(child);
 162                         ret = 0;
 163
 164                         break;
 165
 166                 /* Make the child exit by sending it a sigkill. */
 167                 case PTRACE_KILL:
 168                         ret = 0;
 169
 170                         if (child->exit_state == EXIT_ZOMBIE)
 171                                 break;
 172
 173                         child->exit_code = SIGKILL;
 174
 175                         /* TODO: make sure any pending breakpoint is killed */
 176                         wake_up_process(child);
 177                         break;
 178
 179                 /* Set the trap flag. */
 180                 case PTRACE_SINGLESTEP:
 181                         ret = -EIO;
 182
 183                         if (!valid_signal(data))
 184                                 break;
 185
 186                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 187
 188                         /* TODO: set some clever breakpoint mechanism... */
 189
 190                         child->exit_code = data;
 191                         wake_up_process(child);
 192                         ret = 0;
 193                         break;
 194
 195                 case PTRACE_DETACH:
 196                         ret = ptrace_detach(child, data);
 197                         break;
 198
 199                 /* Get all GP registers from the child. */
 200                 case PTRACE_GETREGS: {
 201                         int i;
 202                         unsigned long tmp;
 203
 204                         ret = 0;
 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                                         break;
 211                                 }
 212
 213                                 data += sizeof(long);
 214                         }
 215
 216                         break;
 217                 }
 218
 219                 /* Set all GP registers in the child. */
 220                 case PTRACE_SETREGS: {
 221                         int i;
 222                         unsigned long tmp;
 223
 224                         ret = 0;
 225                         for (i = 0; i <= PT_MAX; i++) {
 226                                 if (get_user(tmp, datap)) {
 227                                         ret = -EFAULT;
 228                                         break;
 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                         break;
 241                 }
 242
 243                 default:
 244                         ret = ptrace_request(child, request, addr, data);
 245                         break;
 246         }
 247
 248         return ret;
 249 }
 250
 251 void do_syscall_trace(void)
 252 {
 253         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 254                 return;
 255
 256         if (!(current->ptrace & PT_PTRACED))
 257                 return;
 258
 259         /* the 0x80 provides a way for the tracing parent to distinguish
 260            between a syscall stop and SIGTRAP delivery */
 261         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 262                                  ? 0x80 : 0));
 263
 264         /*
 265          * This isn't the same as continuing with a signal, but it will do for
 266          * normal use.
 267          */
 268         if (current->exit_code) {
 269                 send_sig(current->exit_code, current, 1);
 270                 current->exit_code = 0;
 271         }
 272 }