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