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 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
  84 {
  85         struct user * dummy = NULL;
  86         int ret;
  87
  88         switch (request) {
  89         /* when I and D space are separate, these will need to be fixed. */
  90         case PTRACE_PEEKTEXT: /* read word at location addr. */
  91         case PTRACE_PEEKDATA: {
  92                 unsigned long tmp;
  93                 int copied;
  94
  95                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
  96                 ret = -EIO;
  97                 if (copied != sizeof(tmp))
  98                         break;
  99                 ret = put_user(tmp,(unsigned long *) data);
 100                 break;
 101         }
 102
 103         /* read the word at location addr in the USER area. */
 104         case PTRACE_PEEKUSR: {
 105                 unsigned long tmp;
 106
 107                 ret = -EIO;
 108                 if ((addr & 3) || addr < 0 ||
 109                     addr > sizeof(struct user) - 3)
 110                         break;
 111
 112                 if (addr < sizeof(struct pt_regs))
 113                         tmp = get_stack_long(child, addr);
 114                 else if (addr >= (long) &dummy->fpu &&
 115                          addr < (long) &dummy->u_fpvalid) {
 116                         if (!tsk_used_math(child)) {
 117                                 if (addr == (long)&dummy->fpu.fpscr)
 118                                         tmp = FPSCR_INIT;
 119                                 else
 120                                         tmp = 0;
 121                         } else
 122                                 tmp = ((long *)&child->thread.fpu)
 123                                         [(addr - (long)&dummy->fpu) >> 2];
 124                 } else if (addr == (long) &dummy->u_fpvalid)
 125                         tmp = !!tsk_used_math(child);
 126                 else
 127                         tmp = 0;
 128                 ret = put_user(tmp, (unsigned long *)data);
 129                 break;
 130         }
 131
 132         /* when I and D space are separate, this will have to be fixed. */
 133         case PTRACE_POKETEXT: /* write the word at location addr. */
 134         case PTRACE_POKEDATA:
 135                 ret = 0;
 136                 if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 137                         break;
 138                 ret = -EIO;
 139                 break;
 140
 141         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 142                 ret = -EIO;
 143                 if ((addr & 3) || addr < 0 ||
 144                     addr > sizeof(struct user) - 3)
 145                         break;
 146
 147                 if (addr < sizeof(struct pt_regs))
 148                         ret = put_stack_long(child, addr, data);
 149                 else if (addr >= (long) &dummy->fpu &&
 150                          addr < (long) &dummy->u_fpvalid) {
 151                         set_stopped_child_used_math(child);
 152                         ((long *)&child->thread.fpu)
 153                                 [(addr - (long)&dummy->fpu) >> 2] = data;
 154                         ret = 0;
 155                 } else if (addr == (long) &dummy->u_fpvalid) {
 156                         conditional_stopped_child_used_math(data, child);
 157                         ret = 0;
 158                 }
 159                 break;
 160
 161         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 162         case PTRACE_CONT: { /* restart after signal. */
 163                 ret = -EIO;
 164                 if (!valid_signal(data))
 165                         break;
 166                 if (request == PTRACE_SYSCALL)
 167                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 168                 else
 169                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 170                 child->exit_code = data;
 171                 wake_up_process(child);
 172                 ret = 0;
 173                 break;
 174         }
 175
 176 /*
 177  * make the child exit.  Best I can do is send it a sigkill.
 178  * perhaps it should be put in the status that it wants to
 179  * exit.
 180  */
 181         case PTRACE_KILL: {
 182                 ret = 0;
 183                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 184                         break;
 185                 child->exit_code = SIGKILL;
 186                 wake_up_process(child);
 187                 break;
 188         }
 189
 190         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 191                 long pc;
 192                 struct pt_regs *dummy = NULL;
 193
 194                 ret = -EIO;
 195                 if (!valid_signal(data))
 196                         break;
 197                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 198                 if ((child->ptrace & PT_DTRACE) == 0) {
 199                         /* Spurious delayed TF traps may occur */
 200                         child->ptrace |= PT_DTRACE;
 201                 }
 202
 203                 pc = get_stack_long(child, (long)&dummy->pc);
 204
 205                 /* Next scheduling will set up UBC */
 206                 if (child->thread.ubc_pc == 0)
 207                         ubc_usercnt += 1;
 208                 child->thread.ubc_pc = pc;
 209
 210                 child->exit_code = data;
 211                 /* give it a chance to run. */
 212                 wake_up_process(child);
 213                 ret = 0;
 214                 break;
 215         }
 216
 217         case PTRACE_DETACH: /* detach a process that was attached. */
 218                 ret = ptrace_detach(child, data);
 219                 break;
 220
 221 #ifdef CONFIG_SH_DSP
 222         case PTRACE_GETDSPREGS: {
 223                 unsigned long dp;
 224
 225                 ret = -EIO;
 226                 dp = ((unsigned long) child) + THREAD_SIZE -
 227                          sizeof(struct pt_dspregs);
 228                 if (*((int *) (dp - 4)) == SR_FD) {
 229                         copy_to_user(addr, (void *) dp,
 230                                 sizeof(struct pt_dspregs));
 231                         ret = 0;
 232                 }
 233                 break;
 234         }
 235
 236         case PTRACE_SETDSPREGS: {
 237                 unsigned long dp;
 238                 int i;
 239
 240                 ret = -EIO;
 241                 dp = ((unsigned long) child) + THREAD_SIZE -
 242                          sizeof(struct pt_dspregs);
 243                 if (*((int *) (dp - 4)) == SR_FD) {
 244                         copy_from_user((void *) dp, addr,
 245                                 sizeof(struct pt_dspregs));
 246                         ret = 0;
 247                 }
 248                 break;
 249         }
 250 #endif
 251         default:
 252                 ret = ptrace_request(child, request, addr, data);
 253                 break;
 254         }
 255
 256         return ret;
 257 }
 258
 259 asmlinkage void do_syscall_trace(void)
 260 {
 261         struct task_struct *tsk = current;
 262
 263         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 264                 return;
 265         if (!(tsk->ptrace & PT_PTRACED))
 266                 return;
 267         /* the 0x80 provides a way for the tracing parent to distinguish
 268            between a syscall stop and SIGTRAP delivery */
 269         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 270                                  ? 0x80 : 0));
 271
 272         /*
 273          * this isn't the same as continuing with a signal, but it will do
 274          * for normal use.  strace only continues with a signal if the
 275          * stopping signal is not SIGTRAP.  -brl
 276          */
 277         if (tsk->exit_code) {
 278                 send_sig(tsk->exit_code, tsk, 1);
 279                 tsk->exit_code = 0;
 280         }
 281 }