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 *)task_pt_regs(task);
  45         stack += offset;
  46         return (*((int *)stack));
  47 }
  48
  49 /*
  50  * This routine will put a word on the process kernel stack.
  51  */
  52 static inline int put_stack_long(struct task_struct *task, int offset,
  53                                  unsigned long data)
  54 {
  55         unsigned char *stack;
  56
  57         stack = (unsigned char *)task_pt_regs(task);
  58         stack += offset;
  59         *(unsigned long *) stack = data;
  60         return 0;
  61 }
  62
  63 /*
  64  * Called by kernel/ptrace.c when detaching..
  65  *
  66  * Make sure single step bits etc are not set.
  67  */
  68 void ptrace_disable(struct task_struct *child)
  69 {
  70         /* nothing to do.. */
  71 }
  72
  73 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
  74 {
  75         struct user * dummy = NULL;
  76         int ret;
  77
  78         switch (request) {
  79         /* when I and D space are separate, these will need to be fixed. */
  80         case PTRACE_PEEKTEXT: /* read word at location addr. */
  81         case PTRACE_PEEKDATA: {
  82                 unsigned long tmp;
  83                 int copied;
  84
  85                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
  86                 ret = -EIO;
  87                 if (copied != sizeof(tmp))
  88                         break;
  89                 ret = put_user(tmp,(unsigned long *) data);
  90                 break;
  91         }
  92
  93         /* read the word at location addr in the USER area. */
  94         case PTRACE_PEEKUSR: {
  95                 unsigned long tmp;
  96
  97                 ret = -EIO;
  98                 if ((addr & 3) || addr < 0 ||
  99                     addr > sizeof(struct user) - 3)
 100                         break;
 101
 102                 if (addr < sizeof(struct pt_regs))
 103                         tmp = get_stack_long(child, addr);
 104                 else if (addr >= (long) &dummy->fpu &&
 105                          addr < (long) &dummy->u_fpvalid) {
 106                         if (!tsk_used_math(child)) {
 107                                 if (addr == (long)&dummy->fpu.fpscr)
 108                                         tmp = FPSCR_INIT;
 109                                 else
 110                                         tmp = 0;
 111                         } else
 112                                 tmp = ((long *)&child->thread.fpu)
 113                                         [(addr - (long)&dummy->fpu) >> 2];
 114                 } else if (addr == (long) &dummy->u_fpvalid)
 115                         tmp = !!tsk_used_math(child);
 116                 else
 117                         tmp = 0;
 118                 ret = put_user(tmp, (unsigned long *)data);
 119                 break;
 120         }
 121
 122         /* when I and D space are separate, this will have to be fixed. */
 123         case PTRACE_POKETEXT: /* write the word at location addr. */
 124         case PTRACE_POKEDATA:
 125                 ret = 0;
 126                 if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 127                         break;
 128                 ret = -EIO;
 129                 break;
 130
 131         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 132                 ret = -EIO;
 133                 if ((addr & 3) || addr < 0 ||
 134                     addr > sizeof(struct user) - 3)
 135                         break;
 136
 137                 if (addr < sizeof(struct pt_regs))
 138                         ret = put_stack_long(child, addr, data);
 139                 else if (addr >= (long) &dummy->fpu &&
 140                          addr < (long) &dummy->u_fpvalid) {
 141                         set_stopped_child_used_math(child);
 142                         ((long *)&child->thread.fpu)
 143                                 [(addr - (long)&dummy->fpu) >> 2] = data;
 144                         ret = 0;
 145                 } else if (addr == (long) &dummy->u_fpvalid) {
 146                         conditional_stopped_child_used_math(data, child);
 147                         ret = 0;
 148                 }
 149                 break;
 150
 151         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 152         case PTRACE_CONT: { /* restart after signal. */
 153                 ret = -EIO;
 154                 if (!valid_signal(data))
 155                         break;
 156                 if (request == PTRACE_SYSCALL)
 157                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 158                 else
 159                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 160                 child->exit_code = data;
 161                 wake_up_process(child);
 162                 ret = 0;
 163                 break;
 164         }
 165
 166 /*
 167  * make the child exit.  Best I can do is send it a sigkill.
 168  * perhaps it should be put in the status that it wants to
 169  * exit.
 170  */
 171         case PTRACE_KILL: {
 172                 ret = 0;
 173                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 174                         break;
 175                 child->exit_code = SIGKILL;
 176                 wake_up_process(child);
 177                 break;
 178         }
 179
 180         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 181                 long pc;
 182                 struct pt_regs *dummy = NULL;
 183
 184                 ret = -EIO;
 185                 if (!valid_signal(data))
 186                         break;
 187                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 188                 if ((child->ptrace & PT_DTRACE) == 0) {
 189                         /* Spurious delayed TF traps may occur */
 190                         child->ptrace |= PT_DTRACE;
 191                 }
 192
 193                 pc = get_stack_long(child, (long)&dummy->pc);
 194
 195                 /* Next scheduling will set up UBC */
 196                 if (child->thread.ubc_pc == 0)
 197                         ubc_usercnt += 1;
 198                 child->thread.ubc_pc = pc;
 199
 200                 child->exit_code = data;
 201                 /* give it a chance to run. */
 202                 wake_up_process(child);
 203                 ret = 0;
 204                 break;
 205         }
 206
 207         case PTRACE_DETACH: /* detach a process that was attached. */
 208                 ret = ptrace_detach(child, data);
 209                 break;
 210
 211 #ifdef CONFIG_SH_DSP
 212         case PTRACE_GETDSPREGS: {
 213                 unsigned long dp;
 214
 215                 ret = -EIO;
 216                 dp = ((unsigned long) child) + THREAD_SIZE -
 217                          sizeof(struct pt_dspregs);
 218                 if (*((int *) (dp - 4)) == SR_FD) {
 219                         copy_to_user(addr, (void *) dp,
 220                                 sizeof(struct pt_dspregs));
 221                         ret = 0;
 222                 }
 223                 break;
 224         }
 225
 226         case PTRACE_SETDSPREGS: {
 227                 unsigned long dp;
 228                 int i;
 229
 230                 ret = -EIO;
 231                 dp = ((unsigned long) child) + THREAD_SIZE -
 232                          sizeof(struct pt_dspregs);
 233                 if (*((int *) (dp - 4)) == SR_FD) {
 234                         copy_from_user((void *) dp, addr,
 235                                 sizeof(struct pt_dspregs));
 236                         ret = 0;
 237                 }
 238                 break;
 239         }
 240 #endif
 241         default:
 242                 ret = ptrace_request(child, request, addr, data);
 243                 break;
 244         }
 245
 246         return ret;
 247 }
 248
 249 asmlinkage void do_syscall_trace(void)
 250 {
 251         struct task_struct *tsk = current;
 252
 253         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 254                 return;
 255         if (!(tsk->ptrace & PT_PTRACED))
 256                 return;
 257         /* the 0x80 provides a way for the tracing parent to distinguish
 258            between a syscall stop and SIGTRAP delivery */
 259         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 260                                  ? 0x80 : 0));
 261
 262         /*
 263          * this isn't the same as continuing with a signal, but it will do
 264          * for normal use.  strace only continues with a signal if the
 265          * stopping signal is not SIGTRAP.  -brl
 266          */
 267         if (tsk->exit_code) {
 268                 send_sig(tsk->exit_code, tsk, 1);
 269                 tsk->exit_code = 0;
 270         }
 271 }