arch/sh/kernel/ptrace.c

   1 /*
   2  * linux/arch/sh/kernel/ptrace.c
   3  *
   4  * Original x86 implementation:
   5  *      By Ross Biro 1/23/92
   6  *      edited by Linus Torvalds
   7  *
   8  * SuperH version:   Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
   9  *
  10  */
  11
  12 #include <linux/config.h>
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/mm.h>
  16 #include <linux/smp.h>
  17 #include <linux/smp_lock.h>
  18 #include <linux/errno.h>
  19 #include <linux/ptrace.h>
  20 #include <linux/user.h>
  21 #include <linux/slab.h>
  22 #include <linux/security.h>
  23 #include <linux/signal.h>
  24
  25 #include <asm/io.h>
  26 #include <asm/uaccess.h>
  27 #include <asm/pgtable.h>
  28 #include <asm/system.h>
  29 #include <asm/processor.h>
  30 #include <asm/mmu_context.h>
  31
  32 /*
  33  * does not yet catch signals sent when the child dies.
  34  * in exit.c or in signal.c.
  35  */
  36
  37 /*
  38  * This routine will get a word off of the process kernel stack.
  39  */
  40 static inline int get_stack_long(struct task_struct *task, int offset)
  41 {
  42         unsigned char *stack;
  43
  44         stack = (unsigned char *)
  45                 task->thread_info + THREAD_SIZE - sizeof(struct pt_regs)
  46 #ifdef CONFIG_SH_DSP
  47                 - sizeof(struct pt_dspregs)
  48 #endif
  49                 - sizeof(unsigned long);
  50         stack += offset;
  51         return (*((int *)stack));
  52 }
  53
  54 /*
  55  * This routine will put a word on the process kernel stack.
  56  */
  57 static inline int put_stack_long(struct task_struct *task, int offset,
  58                                  unsigned long data)
  59 {
  60         unsigned char *stack;
  61
  62         stack = (unsigned char *)
  63                 task->thread_info + THREAD_SIZE - sizeof(struct pt_regs)
  64 #ifdef CONFIG_SH_DSP
  65                 - sizeof(struct pt_dspregs)
  66 #endif
  67                 - sizeof(unsigned long);
  68         stack += offset;
  69         *(unsigned long *) stack = data;
  70         return 0;
  71 }
  72
  73 /*
  74  * Called by kernel/ptrace.c when detaching..
  75  *
  76  * Make sure single step bits etc are not set.
  77  */
  78 void ptrace_disable(struct task_struct *child)
  79 {
  80         /* nothing to do.. */
  81 }
  82
  83 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
  84 {
  85         struct task_struct *child;
  86         struct user * dummy = NULL;
  87         int ret;
  88
  89         lock_kernel();
  90         ret = -EPERM;
  91         if (request == PTRACE_TRACEME) {
  92                 /* are we already being traced? */
  93                 if (current->ptrace & PT_PTRACED)
  94                         goto out;
  95                 ret = security_ptrace(current->parent, current);
  96                 if (ret)
  97                         goto out;
  98                 /* set the ptrace bit in the process flags. */
  99                 current->ptrace |= PT_PTRACED;
 100                 ret = 0;
 101                 goto out;
 102         }
 103         ret = -ESRCH;
 104         read_lock(&tasklist_lock);
 105         child = find_task_by_pid(pid);
 106         if (child)
 107                 get_task_struct(child);
 108         read_unlock(&tasklist_lock);
 109         if (!child)
 110                 goto out;
 111
 112         ret = -EPERM;
 113         if (pid == 1)           /* you may not mess with init */
 114                 goto out_tsk;
 115
 116         if (request == PTRACE_ATTACH) {
 117                 ret = ptrace_attach(child);
 118                 goto out_tsk;
 119         }
 120
 121         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 122         if (ret < 0)
 123                 goto out_tsk;
 124
 125         switch (request) {
 126         /* when I and D space are separate, these will need to be fixed. */
 127         case PTRACE_PEEKTEXT: /* read word at location addr. */
 128         case PTRACE_PEEKDATA: {
 129                 unsigned long tmp;
 130                 int copied;
 131
 132                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 133                 ret = -EIO;
 134                 if (copied != sizeof(tmp))
 135                         break;
 136                 ret = put_user(tmp,(unsigned long *) data);
 137                 break;
 138         }
 139
 140         /* read the word at location addr in the USER area. */
 141         case PTRACE_PEEKUSR: {
 142                 unsigned long tmp;
 143
 144                 ret = -EIO;
 145                 if ((addr & 3) || addr < 0 ||
 146                     addr > sizeof(struct user) - 3)
 147                         break;
 148
 149                 if (addr < sizeof(struct pt_regs))
 150                         tmp = get_stack_long(child, addr);
 151                 else if (addr >= (long) &dummy->fpu &&
 152                          addr < (long) &dummy->u_fpvalid) {
 153                         if (!tsk_used_math(child)) {
 154                                 if (addr == (long)&dummy->fpu.fpscr)
 155                                         tmp = FPSCR_INIT;
 156                                 else
 157                                         tmp = 0;
 158                         } else
 159                                 tmp = ((long *)&child->thread.fpu)
 160                                         [(addr - (long)&dummy->fpu) >> 2];
 161                 } else if (addr == (long) &dummy->u_fpvalid)
 162                         tmp = !!tsk_used_math(child);
 163                 else
 164                         tmp = 0;
 165                 ret = put_user(tmp, (unsigned long *)data);
 166                 break;
 167         }
 168
 169         /* when I and D space are separate, this will have to be fixed. */
 170         case PTRACE_POKETEXT: /* write the word at location addr. */
 171         case PTRACE_POKEDATA:
 172                 ret = 0;
 173                 if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 174                         break;
 175                 ret = -EIO;
 176                 break;
 177
 178         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 179                 ret = -EIO;
 180                 if ((addr & 3) || addr < 0 ||
 181                     addr > sizeof(struct user) - 3)
 182                         break;
 183
 184                 if (addr < sizeof(struct pt_regs))
 185                         ret = put_stack_long(child, addr, data);
 186                 else if (addr >= (long) &dummy->fpu &&
 187                          addr < (long) &dummy->u_fpvalid) {
 188                         set_stopped_child_used_math(child);
 189                         ((long *)&child->thread.fpu)
 190                                 [(addr - (long)&dummy->fpu) >> 2] = data;
 191                         ret = 0;
 192                 } else if (addr == (long) &dummy->u_fpvalid) {
 193                         conditional_stopped_child_used_math(data, child);
 194                         ret = 0;
 195                 }
 196                 break;
 197
 198         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 199         case PTRACE_CONT: { /* restart after signal. */
 200                 ret = -EIO;
 201                 if (!valid_signal(data))
 202                         break;
 203                 if (request == PTRACE_SYSCALL)
 204                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 205                 else
 206                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 207                 child->exit_code = data;
 208                 wake_up_process(child);
 209                 ret = 0;
 210                 break;
 211         }
 212
 213 /*
 214  * make the child exit.  Best I can do is send it a sigkill.
 215  * perhaps it should be put in the status that it wants to
 216  * exit.
 217  */
 218         case PTRACE_KILL: {
 219                 ret = 0;
 220                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 221                         break;
 222                 child->exit_code = SIGKILL;
 223                 wake_up_process(child);
 224                 break;
 225         }
 226
 227         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 228                 long pc;
 229                 struct pt_regs *dummy = NULL;
 230
 231                 ret = -EIO;
 232                 if (!valid_signal(data))
 233                         break;
 234                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 235                 if ((child->ptrace & PT_DTRACE) == 0) {
 236                         /* Spurious delayed TF traps may occur */
 237                         child->ptrace |= PT_DTRACE;
 238                 }
 239
 240                 pc = get_stack_long(child, (long)&dummy->pc);
 241
 242                 /* Next scheduling will set up UBC */
 243                 if (child->thread.ubc_pc == 0)
 244                         ubc_usercnt += 1;
 245                 child->thread.ubc_pc = pc;
 246
 247                 child->exit_code = data;
 248                 /* give it a chance to run. */
 249                 wake_up_process(child);
 250                 ret = 0;
 251                 break;
 252         }
 253
 254         case PTRACE_DETACH: /* detach a process that was attached. */
 255                 ret = ptrace_detach(child, data);
 256                 break;
 257
 258 #ifdef CONFIG_SH_DSP
 259         case PTRACE_GETDSPREGS: {
 260                 unsigned long dp;
 261
 262                 ret = -EIO;
 263                 dp = ((unsigned long) child) + THREAD_SIZE -
 264                          sizeof(struct pt_dspregs);
 265                 if (*((int *) (dp - 4)) == SR_FD) {
 266                         copy_to_user(addr, (void *) dp,
 267                                 sizeof(struct pt_dspregs));
 268                         ret = 0;
 269                 }
 270                 break;
 271         }
 272
 273         case PTRACE_SETDSPREGS: {
 274                 unsigned long dp;
 275                 int i;
 276
 277                 ret = -EIO;
 278                 dp = ((unsigned long) child) + THREAD_SIZE -
 279                          sizeof(struct pt_dspregs);
 280                 if (*((int *) (dp - 4)) == SR_FD) {
 281                         copy_from_user((void *) dp, addr,
 282                                 sizeof(struct pt_dspregs));
 283                         ret = 0;
 284                 }
 285                 break;
 286         }
 287 #endif
 288         default:
 289                 ret = ptrace_request(child, request, addr, data);
 290                 break;
 291         }
 292 out_tsk:
 293         put_task_struct(child);
 294 out:
 295         unlock_kernel();
 296         return ret;
 297 }
 298
 299 asmlinkage void do_syscall_trace(void)
 300 {
 301         struct task_struct *tsk = current;
 302
 303         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 304                 return;
 305         if (!(tsk->ptrace & PT_PTRACED))
 306                 return;
 307         /* the 0x80 provides a way for the tracing parent to distinguish
 308            between a syscall stop and SIGTRAP delivery */
 309         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 310                                  ? 0x80 : 0));
 311
 312         /*
 313          * this isn't the same as continuing with a signal, but it will do
 314          * for normal use.  strace only continues with a signal if the
 315          * stopping signal is not SIGTRAP.  -brl
 316          */
 317         if (tsk->exit_code) {
 318                 send_sig(tsk->exit_code, tsk, 1);
 319                 tsk->exit_code = 0;
 320         }
 321 }