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