arch/h8300/kernel/ptrace.c

   1 /*
   2  *  linux/arch/h8300/kernel/ptrace.c
   3  *
   4  *  Yoshinori Sato <ysato@users.sourceforge.jp>
   5  *
   6  *  Based on:
   7  *  linux/arch/m68k/kernel/ptrace.c
   8  *
   9  *  Copyright (C) 1994 by Hamish Macdonald
  10  *  Taken from linux/kernel/ptrace.c and modified for M680x0.
  11  *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
  12  *
  13  * This file is subject to the terms and conditions of the GNU General
  14  * Public License.  See the file COPYING in the main directory of
  15  * this archive for more details.
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/sched.h>
  20 #include <linux/mm.h>
  21 #include <linux/smp.h>
  22 #include <linux/smp_lock.h>
  23 #include <linux/errno.h>
  24 #include <linux/ptrace.h>
  25 #include <linux/user.h>
  26 #include <linux/config.h>
  27
  28 #include <asm/uaccess.h>
  29 #include <asm/page.h>
  30 #include <asm/pgtable.h>
  31 #include <asm/system.h>
  32 #include <asm/processor.h>
  33 #include <asm/signal.h>
  34
  35 /* cpu depend functions */
  36 extern long h8300_get_reg(struct task_struct *task, int regno);
  37 extern int  h8300_put_reg(struct task_struct *task, int regno, unsigned long data);
  38 extern void h8300_disable_trace(struct task_struct *child);
  39 extern void h8300_enable_trace(struct task_struct *child);
  40
  41 /*
  42  * does not yet catch signals sent when the child dies.
  43  * in exit.c or in signal.c.
  44  */
  45
  46 inline
  47 static int read_long(struct task_struct * tsk, unsigned long addr,
  48         unsigned long * result)
  49 {
  50         *result = *(unsigned long *)addr;
  51         return 0;
  52 }
  53
  54 void ptrace_disable(struct task_struct *child)
  55 {
  56         h8300_disable_trace(child);
  57 }
  58
  59 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
  60 {
  61         struct task_struct *child;
  62         int ret;
  63
  64         lock_kernel();
  65         ret = -EPERM;
  66         if (request == PTRACE_TRACEME) {
  67                 /* are we already being traced? */
  68                 if (current->ptrace & PT_PTRACED)
  69                         goto out;
  70                 /* set the ptrace bit in the process flags. */
  71                 current->ptrace |= PT_PTRACED;
  72                 ret = 0;
  73                 goto out;
  74         }
  75         ret = -ESRCH;
  76         read_lock(&tasklist_lock);
  77         child = find_task_by_pid(pid);
  78         if (child)
  79                 get_task_struct(child);
  80         read_unlock(&tasklist_lock);
  81         if (!child)
  82                 goto out;
  83         if (!vx_check(vx_task_xid(child), VX_WATCH|VX_IDENT))
  84                 goto out_tsk;
  85
  86         ret = -EPERM;
  87         if (pid == 1)           /* you may not mess with init */
  88                 goto out_tsk;
  89
  90         if (request == PTRACE_ATTACH) {
  91                 ret = ptrace_attach(child);
  92                 goto out_tsk;
  93         }
  94         ret = -ESRCH;
  95         if (!(child->ptrace & PT_PTRACED))
  96                 goto out_tsk;
  97         if (child->state != TASK_STOPPED) {
  98                 if (request != PTRACE_KILL)
  99                         goto out_tsk;
 100         }
 101         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 102         if (ret < 0)
 103                 goto out_tsk;
 104
 105         switch (request) {
 106                 case PTRACE_PEEKTEXT: /* read word at location addr. */
 107                 case PTRACE_PEEKDATA: {
 108                         unsigned long tmp;
 109
 110                         ret = read_long(child, addr, &tmp);
 111                         if (ret < 0)
 112                                 break ;
 113                         ret = put_user(tmp, (unsigned long *) data);
 114                         break ;
 115                 }
 116
 117         /* read the word at location addr in the USER area. */
 118                 case PTRACE_PEEKUSR: {
 119                         unsigned long tmp;
 120
 121                         if ((addr & 3) || addr < 0 || addr >= sizeof(struct user))
 122                                 ret = -EIO;
 123
 124                         tmp = 0;  /* Default return condition */
 125                         addr = addr >> 2; /* temporary hack. */
 126                         if (addr < H8300_REGS_NO)
 127                                 tmp = h8300_get_reg(child, addr);
 128                         else {
 129                                 ret = -EIO;
 130                                 break ;
 131                         }
 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                         if ((addr & 3) || addr < 0 || addr >= sizeof(struct user)) {
 147                                 ret = -EIO;
 148                                 break ;
 149                         }
 150                         addr = addr >> 2; /* temporary hack. */
 151
 152                         if (addr == PT_ORIG_ER0) {
 153                                 ret = -EIO;
 154                                 break ;
 155                         }
 156                         if (addr < H8300_REGS_NO) {
 157                                 ret = h8300_put_reg(child, addr, data);
 158                                 break ;
 159                         }
 160                         ret = -EIO;
 161                         break ;
 162                 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 163                 case PTRACE_CONT: { /* restart after signal. */
 164                         ret = -EIO;
 165                         if ((unsigned long) data >= _NSIG)
 166                                 break ;
 167                         if (request == PTRACE_SYSCALL)
 168                                 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 169                         else
 170                                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 171                         child->exit_code = data;
 172                         wake_up_process(child);
 173                         /* make sure the single step bit is not set. */
 174                         h8300_disable_trace(child);
 175                         ret = 0;
 176                 }
 177
 178 /*
 179  * make the child exit.  Best I can do is send it a sigkill.
 180  * perhaps it should be put in the status that it wants to
 181  * exit.
 182  */
 183                 case PTRACE_KILL: {
 184
 185                         ret = 0;
 186                         if (child->state == TASK_ZOMBIE) /* already dead */
 187                                 break;
 188                         child->exit_code = SIGKILL;
 189                         h8300_disable_trace(child);
 190                         wake_up_process(child);
 191                         break;
 192                 }
 193
 194                 case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 195                         ret = -EIO;
 196                         if ((unsigned long) data > _NSIG)
 197                                 break;
 198                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 199                         child->exit_code = data;
 200                         h8300_enable_trace(child);
 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                 case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 211                         int i;
 212                         unsigned long tmp;
 213                         for (i = 0; i < H8300_REGS_NO; i++) {
 214                             tmp = h8300_get_reg(child, i);
 215                             if (put_user(tmp, (unsigned long *) data)) {
 216                                 ret = -EFAULT;
 217                                 break;
 218                             }
 219                             data += sizeof(long);
 220                         }
 221                         ret = 0;
 222                         break;
 223                 }
 224
 225                 case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 226                         int i;
 227                         unsigned long tmp;
 228                         for (i = 0; i < H8300_REGS_NO; i++) {
 229                             if (get_user(tmp, (unsigned long *) data)) {
 230                                 ret = -EFAULT;
 231                                 break;
 232                             }
 233                             h8300_put_reg(child, i, tmp);
 234                             data += sizeof(long);
 235                         }
 236                         ret = 0;
 237                         break;
 238                 }
 239
 240                 default:
 241                         ret = -EIO;
 242                         break;
 243         }
 244 out_tsk:
 245         put_task_struct(child);
 246 out:
 247         unlock_kernel();
 248         return ret;
 249 }
 250
 251 asmlinkage void syscall_trace(void)
 252 {
 253         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 254                 return;
 255         if (!(current->ptrace & PT_PTRACED))
 256                 return;
 257         current->exit_code = SIGTRAP;
 258         current->state = TASK_STOPPED;
 259         notify_parent(current, SIGCHLD);
 260         schedule();
 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 (current->exit_code) {
 267                 send_sig(current->exit_code, current, 1);
 268                 current->exit_code = 0;
 269         }
 270 }