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/kernel.h>
  13 #include <linux/sched.h>
  14 #include <linux/mm.h>
  15 #include <linux/smp.h>
  16 #include <linux/smp_lock.h>
  17 #include <linux/errno.h>
  18 #include <linux/ptrace.h>
  19 #include <linux/user.h>
  20 #include <linux/slab.h>
  21 #include <linux/security.h>
  22 #include <linux/signal.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 *)task_pt_regs(task);
  44         stack += offset;
  45         return (*((int *)stack));
  46 }
  47
  48 /*
  49  * This routine will put a word on the process kernel stack.
  50  */
  51 static inline int put_stack_long(struct task_struct *task, int offset,
  52                                  unsigned long data)
  53 {
  54         unsigned char *stack;
  55
  56         stack = (unsigned char *)task_pt_regs(task);
  57         stack += offset;
  58         *(unsigned long *) stack = data;
  59         return 0;
  60 }
  61
  62 /*
  63  * Called by kernel/ptrace.c when detaching..
  64  *
  65  * Make sure single step bits etc are not set.
  66  */
  67 void ptrace_disable(struct task_struct *child)
  68 {
  69         /* nothing to do.. */
  70 }
  71
  72 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
  73 {
  74         struct user * dummy = NULL;
  75         int ret;
  76
  77         switch (request) {
  78         /* when I and D space are separate, these will need to be fixed. */
  79         case PTRACE_PEEKTEXT: /* read word at location addr. */
  80         case PTRACE_PEEKDATA: {
  81                 unsigned long tmp;
  82                 int copied;
  83
  84                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
  85                 ret = -EIO;
  86                 if (copied != sizeof(tmp))
  87                         break;
  88                 ret = put_user(tmp,(unsigned long *) data);
  89                 break;
  90         }
  91
  92         /* read the word at location addr in the USER area. */
  93         case PTRACE_PEEKUSR: {
  94                 unsigned long tmp;
  95
  96                 ret = -EIO;
  97                 if ((addr & 3) || addr < 0 ||
  98                     addr > sizeof(struct user) - 3)
  99                         break;
 100
 101                 if (addr < sizeof(struct pt_regs))
 102                         tmp = get_stack_long(child, addr);
 103                 else if (addr >= (long) &dummy->fpu &&
 104                          addr < (long) &dummy->u_fpvalid) {
 105                         if (!tsk_used_math(child)) {
 106                                 if (addr == (long)&dummy->fpu.fpscr)
 107                                         tmp = FPSCR_INIT;
 108                                 else
 109                                         tmp = 0;
 110                         } else
 111                                 tmp = ((long *)&child->thread.fpu)
 112                                         [(addr - (long)&dummy->fpu) >> 2];
 113                 } else if (addr == (long) &dummy->u_fpvalid)
 114                         tmp = !!tsk_used_math(child);
 115                 else
 116                         tmp = 0;
 117                 ret = put_user(tmp, (unsigned long *)data);
 118                 break;
 119         }
 120
 121         /* when I and D space are separate, this will have to be fixed. */
 122         case PTRACE_POKETEXT: /* write the word at location addr. */
 123         case PTRACE_POKEDATA:
 124                 ret = 0;
 125                 if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 126                         break;
 127                 ret = -EIO;
 128                 break;
 129
 130         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 131                 ret = -EIO;
 132                 if ((addr & 3) || addr < 0 ||
 133                     addr > sizeof(struct user) - 3)
 134                         break;
 135
 136                 if (addr < sizeof(struct pt_regs))
 137                         ret = put_stack_long(child, addr, data);
 138                 else if (addr >= (long) &dummy->fpu &&
 139                          addr < (long) &dummy->u_fpvalid) {
 140                         set_stopped_child_used_math(child);
 141                         ((long *)&child->thread.fpu)
 142                                 [(addr - (long)&dummy->fpu) >> 2] = data;
 143                         ret = 0;
 144                 } else if (addr == (long) &dummy->u_fpvalid) {
 145                         conditional_stopped_child_used_math(data, child);
 146                         ret = 0;
 147                 }
 148                 break;
 149
 150         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 151         case PTRACE_CONT: { /* restart after signal. */
 152                 ret = -EIO;
 153                 if (!valid_signal(data))
 154                         break;
 155                 if (request == PTRACE_SYSCALL)
 156                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 157                 else
 158                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 159                 child->exit_code = data;
 160                 wake_up_process(child);
 161                 ret = 0;
 162                 break;
 163         }
 164
 165 /*
 166  * make the child exit.  Best I can do is send it a sigkill.
 167  * perhaps it should be put in the status that it wants to
 168  * exit.
 169  */
 170         case PTRACE_KILL: {
 171                 ret = 0;
 172                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 173                         break;
 174                 child->exit_code = SIGKILL;
 175                 wake_up_process(child);
 176                 break;
 177         }
 178
 179         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 180                 long pc;
 181                 struct pt_regs *dummy = NULL;
 182
 183                 ret = -EIO;
 184                 if (!valid_signal(data))
 185                         break;
 186                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 187                 if ((child->ptrace & PT_DTRACE) == 0) {
 188                         /* Spurious delayed TF traps may occur */
 189                         child->ptrace |= PT_DTRACE;
 190                 }
 191
 192                 pc = get_stack_long(child, (long)&dummy->pc);
 193
 194                 /* Next scheduling will set up UBC */
 195                 if (child->thread.ubc_pc == 0)
 196                         ubc_usercnt += 1;
 197                 child->thread.ubc_pc = pc;
 198
 199                 child->exit_code = data;
 200                 /* give it a chance to run. */
 201                 wake_up_process(child);
 202                 ret = 0;
 203                 break;
 204         }
 205
 206         case PTRACE_DETACH: /* detach a process that was attached. */
 207                 ret = ptrace_detach(child, data);
 208                 break;
 209
 210 #ifdef CONFIG_SH_DSP
 211         case PTRACE_GETDSPREGS: {
 212                 unsigned long dp;
 213
 214                 ret = -EIO;
 215                 dp = ((unsigned long) child) + THREAD_SIZE -
 216                          sizeof(struct pt_dspregs);
 217                 if (*((int *) (dp - 4)) == SR_FD) {
 218                         copy_to_user(addr, (void *) dp,
 219                                 sizeof(struct pt_dspregs));
 220                         ret = 0;
 221                 }
 222                 break;
 223         }
 224
 225         case PTRACE_SETDSPREGS: {
 226                 unsigned long dp;
 227                 int i;
 228
 229                 ret = -EIO;
 230                 dp = ((unsigned long) child) + THREAD_SIZE -
 231                          sizeof(struct pt_dspregs);
 232                 if (*((int *) (dp - 4)) == SR_FD) {
 233                         copy_from_user((void *) dp, addr,
 234                                 sizeof(struct pt_dspregs));
 235                         ret = 0;
 236                 }
 237                 break;
 238         }
 239 #endif
 240         default:
 241                 ret = ptrace_request(child, request, addr, data);
 242                 break;
 243         }
 244
 245         return ret;
 246 }
 247
 248 asmlinkage void do_syscall_trace(void)
 249 {
 250         struct task_struct *tsk = current;
 251
 252         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 253                 return;
 254         if (!(tsk->ptrace & PT_PTRACED))
 255                 return;
 256         /* the 0x80 provides a way for the tracing parent to distinguish
 257            between a syscall stop and SIGTRAP delivery */
 258         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 259                                  ? 0x80 : 0));
 260
 261         /*
 262          * this isn't the same as continuing with a signal, but it will do
 263          * for normal use.  strace only continues with a signal if the
 264          * stopping signal is not SIGTRAP.  -brl
 265          */
 266         if (tsk->exit_code) {
 267                 send_sig(tsk->exit_code, tsk, 1);
 268                 tsk->exit_code = 0;
 269         }
 270 }