arch/m68k/kernel/ptrace.c

   1 /*
   2  *  linux/arch/m68k/kernel/ptrace.c
   3  *
   4  *  Copyright (C) 1994 by Hamish Macdonald
   5  *  Taken from linux/kernel/ptrace.c and modified for M680x0.
   6  *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
   7  *
   8  * This file is subject to the terms and conditions of the GNU General
   9  * Public License.  See the file COPYING in the main directory of
  10  * this archive for more details.
  11  */
  12
  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/config.h>
  22 #include <linux/signal.h>
  23
  24 #include <asm/uaccess.h>
  25 #include <asm/page.h>
  26 #include <asm/pgtable.h>
  27 #include <asm/system.h>
  28 #include <asm/processor.h>
  29
  30 /*
  31  * does not yet catch signals sent when the child dies.
  32  * in exit.c or in signal.c.
  33  */
  34
  35 /* determines which bits in the SR the user has access to. */
  36 /* 1 = access 0 = no access */
  37 #define SR_MASK 0x001f
  38
  39 /* sets the trace bits. */
  40 #define TRACE_BITS 0x8000
  41
  42 /* Find the stack offset for a register, relative to thread.esp0. */
  43 #define PT_REG(reg)     ((long)&((struct pt_regs *)0)->reg)
  44 #define SW_REG(reg)     ((long)&((struct switch_stack *)0)->reg \
  45                          - sizeof(struct switch_stack))
  46 /* Mapping from PT_xxx to the stack offset at which the register is
  47    saved.  Notice that usp has no stack-slot and needs to be treated
  48    specially (see get_reg/put_reg below). */
  49 static int regoff[] = {
  50         [0]     = PT_REG(d1),
  51         [1]     = PT_REG(d2),
  52         [2]     = PT_REG(d3),
  53         [3]     = PT_REG(d4),
  54         [4]     = PT_REG(d5),
  55         [5]     = SW_REG(d6),
  56         [6]     = SW_REG(d7),
  57         [7]     = PT_REG(a0),
  58         [8]     = PT_REG(a1),
  59         [9]     = PT_REG(a2),
  60         [10]    = SW_REG(a3),
  61         [11]    = SW_REG(a4),
  62         [12]    = SW_REG(a5),
  63         [13]    = SW_REG(a6),
  64         [14]    = PT_REG(d0),
  65         [15]    = -1,
  66         [16]    = PT_REG(orig_d0),
  67         [17]    = PT_REG(sr),
  68         [18]    = PT_REG(pc),
  69 };
  70
  71 /*
  72  * Get contents of register REGNO in task TASK.
  73  */
  74 static inline long get_reg(struct task_struct *task, int regno)
  75 {
  76         unsigned long *addr;
  77
  78         if (regno == PT_USP)
  79                 addr = &task->thread.usp;
  80         else if (regno < sizeof(regoff)/sizeof(regoff[0]))
  81                 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
  82         else
  83                 return 0;
  84         return *addr;
  85 }
  86
  87 /*
  88  * Write contents of register REGNO in task TASK.
  89  */
  90 static inline int put_reg(struct task_struct *task, int regno,
  91                           unsigned long data)
  92 {
  93         unsigned long *addr;
  94
  95         if (regno == PT_USP)
  96                 addr = &task->thread.usp;
  97         else if (regno < sizeof(regoff)/sizeof(regoff[0]))
  98                 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
  99         else
 100                 return -1;
 101         *addr = data;
 102         return 0;
 103 }
 104
 105 /*
 106  * Make sure the single step bit is not set.
 107  */
 108 static inline void singlestep_disable(struct task_struct *child)
 109 {
 110         unsigned long tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 111         put_reg(child, PT_SR, tmp);
 112         child->thread.work.delayed_trace = 0;
 113 }
 114
 115 /*
 116  * Called by kernel/ptrace.c when detaching..
 117  */
 118 void ptrace_disable(struct task_struct *child)
 119 {
 120         singlestep_disable(child);
 121         child->thread.work.syscall_trace = 0;
 122 }
 123
 124 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
 125 {
 126         struct task_struct *child;
 127         unsigned long tmp;
 128         int i, ret = 0;
 129
 130         lock_kernel();
 131         if (request == PTRACE_TRACEME) {
 132                 /* are we already being traced? */
 133                 if (current->ptrace & PT_PTRACED) {
 134                         ret = -EPERM;
 135                         goto out;
 136                 }
 137                 /* set the ptrace bit in the process flags. */
 138                 current->ptrace |= PT_PTRACED;
 139                 goto out;
 140         }
 141         read_lock(&tasklist_lock);
 142         child = find_task_by_pid(pid);
 143         if (child)
 144                 get_task_struct(child);
 145         read_unlock(&tasklist_lock);
 146         if (unlikely(!child)) {
 147                 ret = -ESRCH;
 148                 goto out;
 149         }
 150
 151         /* you may not mess with init */
 152         if (unlikely(pid == 1)) {
 153                 ret = -EPERM;
 154                 goto out_tsk;
 155         }
 156
 157         if (request == PTRACE_ATTACH) {
 158                 ret = ptrace_attach(child);
 159                 goto out_tsk;
 160         }
 161
 162         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 163         if (ret)
 164                 goto out_tsk;
 165
 166         switch (request) {
 167         /* when I and D space are separate, these will need to be fixed. */
 168         case PTRACE_PEEKTEXT:   /* read word at location addr. */
 169         case PTRACE_PEEKDATA:
 170                 i = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 171                 if (i != sizeof(tmp))
 172                         goto out_eio;
 173                 ret = put_user(tmp, (unsigned long *)data);
 174                 break;
 175
 176         /* read the word at location addr in the USER area. */
 177         case PTRACE_PEEKUSR:
 178                 if (addr & 3)
 179                         goto out_eio;
 180                 addr >>= 2;     /* temporary hack. */
 181
 182                 if (addr >= 0 && addr < 19) {
 183                         tmp = get_reg(child, addr);
 184                         if (addr == PT_SR)
 185                                 tmp >>= 16;
 186                 } else if (addr >= 21 && addr < 49) {
 187                         tmp = child->thread.fp[addr - 21];
 188                         /* Convert internal fpu reg representation
 189                          * into long double format
 190                          */
 191                         if (FPU_IS_EMU && (addr < 45) && !(addr % 3))
 192                                 tmp = ((tmp & 0xffff0000) << 15) |
 193                                       ((tmp & 0x0000ffff) << 16);
 194                 } else
 195                         break;
 196                 ret = put_user(tmp, (unsigned long *)data);
 197                 break;
 198
 199         /* when I and D space are separate, this will have to be fixed. */
 200         case PTRACE_POKETEXT:   /* write the word at location addr. */
 201         case PTRACE_POKEDATA:
 202                 if (access_process_vm(child, addr, &data, sizeof(data), 1) != sizeof(data))
 203                         goto out_eio;
 204                 break;
 205
 206         case PTRACE_POKEUSR:    /* write the word at location addr in the USER area */
 207                 if (addr & 3)
 208                         goto out_eio;
 209                 addr >>= 2;     /* temporary hack. */
 210
 211                 if (addr == PT_SR) {
 212                         data &= SR_MASK;
 213                         data <<= 16;
 214                         data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 215                 } else if (addr >= 0 && addr < 19) {
 216                         if (put_reg(child, addr, data))
 217                                 goto out_eio;
 218                 } else if (addr >= 21 && addr < 48) {
 219                         /* Convert long double format
 220                          * into internal fpu reg representation
 221                          */
 222                         if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) {
 223                                 data = (unsigned long)data << 15;
 224                                 data = (data & 0xffff0000) |
 225                                        ((data & 0x0000ffff) >> 1);
 226                         }
 227                         child->thread.fp[addr - 21] = data;
 228                 } else
 229                         goto out_eio;
 230                 break;
 231
 232         case PTRACE_SYSCALL:    /* continue and stop at next (return from) syscall */
 233         case PTRACE_CONT:       /* restart after signal. */
 234                 if (!valid_signal(data))
 235                         goto out_eio;
 236
 237                 if (request == PTRACE_SYSCALL)
 238                         child->thread.work.syscall_trace = ~0;
 239                 else
 240                         child->thread.work.syscall_trace = 0;
 241                 child->exit_code = data;
 242                 singlestep_disable(child);
 243                 wake_up_process(child);
 244                 break;
 245
 246         /*
 247          * make the child exit.  Best I can do is send it a sigkill.
 248          * perhaps it should be put in the status that it wants to
 249          * exit.
 250          */
 251         case PTRACE_KILL:
 252                 if (child->exit_state == EXIT_ZOMBIE) /* already dead */
 253                         break;
 254                 child->exit_code = SIGKILL;
 255                 singlestep_disable(child);
 256                 wake_up_process(child);
 257                 break;
 258
 259         case PTRACE_SINGLESTEP: /* set the trap flag. */
 260                 if (!valid_signal(data))
 261                         goto out_eio;
 262
 263                 child->thread.work.syscall_trace = 0;
 264                 tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
 265                 put_reg(child, PT_SR, tmp);
 266                 child->thread.work.delayed_trace = 1;
 267
 268                 child->exit_code = data;
 269                 /* give it a chance to run. */
 270                 wake_up_process(child);
 271                 break;
 272
 273         case PTRACE_DETACH:     /* detach a process that was attached. */
 274                 ret = ptrace_detach(child, data);
 275                 break;
 276
 277         case PTRACE_GETREGS:    /* Get all gp regs from the child. */
 278                 for (i = 0; i < 19; i++) {
 279                         tmp = get_reg(child, i);
 280                         if (i == PT_SR)
 281                                 tmp >>= 16;
 282                         ret = put_user(tmp, (unsigned long *)data);
 283                         if (ret)
 284                                 break;
 285                         data += sizeof(long);
 286                 }
 287                 break;
 288
 289         case PTRACE_SETREGS:    /* Set all gp regs in the child. */
 290                 for (i = 0; i < 19; i++) {
 291                         ret = get_user(tmp, (unsigned long *)data);
 292                         if (ret)
 293                                 break;
 294                         if (i == PT_SR) {
 295                                 tmp &= SR_MASK;
 296                                 tmp <<= 16;
 297                                 tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 298                         }
 299                         put_reg(child, i, tmp);
 300                         data += sizeof(long);
 301                 }
 302                 break;
 303
 304         case PTRACE_GETFPREGS:  /* Get the child FPU state. */
 305                 if (copy_to_user((void *)data, &child->thread.fp,
 306                                  sizeof(struct user_m68kfp_struct)))
 307                         ret = -EFAULT;
 308                 break;
 309
 310         case PTRACE_SETFPREGS:  /* Set the child FPU state. */
 311                 if (copy_from_user(&child->thread.fp, (void *)data,
 312                                    sizeof(struct user_m68kfp_struct)))
 313                         ret = -EFAULT;
 314                 break;
 315
 316         default:
 317                 ret = ptrace_request(child, request, addr, data);
 318                 break;
 319         }
 320 out_tsk:
 321         put_task_struct(child);
 322 out:
 323         unlock_kernel();
 324         return ret;
 325 out_eio:
 326         ret = -EIO;
 327         goto out_tsk;
 328 }
 329
 330 asmlinkage void syscall_trace(void)
 331 {
 332         if (!current->thread.work.delayed_trace &&
 333             !current->thread.work.syscall_trace)
 334                 return;
 335         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 336                                  ? 0x80 : 0));
 337         /*
 338          * this isn't the same as continuing with a signal, but it will do
 339          * for normal use.  strace only continues with a signal if the
 340          * stopping signal is not SIGTRAP.  -brl
 341          */
 342         if (current->exit_code) {
 343                 send_sig(current->exit_code, current, 1);
 344                 current->exit_code = 0;
 345         }
 346 }