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