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         clear_tsk_thread_flag(child, TIF_DELAYED_TRACE);
 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         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 122 }
 123
 124 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 125 {
 126         unsigned long tmp;
 127         int i, ret = 0;
 128
 129         switch (request) {
 130         /* when I and D space are separate, these will need to be fixed. */
 131         case PTRACE_PEEKTEXT:   /* read word at location addr. */
 132         case PTRACE_PEEKDATA:
 133                 i = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 134                 if (i != sizeof(tmp))
 135                         goto out_eio;
 136                 ret = put_user(tmp, (unsigned long *)data);
 137                 break;
 138
 139         /* read the word at location addr in the USER area. */
 140         case PTRACE_PEEKUSR:
 141                 if (addr & 3)
 142                         goto out_eio;
 143                 addr >>= 2;     /* temporary hack. */
 144
 145                 if (addr >= 0 && addr < 19) {
 146                         tmp = get_reg(child, addr);
 147                         if (addr == PT_SR)
 148                                 tmp >>= 16;
 149                 } else if (addr >= 21 && addr < 49) {
 150                         tmp = child->thread.fp[addr - 21];
 151                         /* Convert internal fpu reg representation
 152                          * into long double format
 153                          */
 154                         if (FPU_IS_EMU && (addr < 45) && !(addr % 3))
 155                                 tmp = ((tmp & 0xffff0000) << 15) |
 156                                       ((tmp & 0x0000ffff) << 16);
 157                 } else
 158                         break;
 159                 ret = put_user(tmp, (unsigned long *)data);
 160                 break;
 161
 162         /* when I and D space are separate, this will have to be fixed. */
 163         case PTRACE_POKETEXT:   /* write the word at location addr. */
 164         case PTRACE_POKEDATA:
 165                 if (access_process_vm(child, addr, &data, sizeof(data), 1) != sizeof(data))
 166                         goto out_eio;
 167                 break;
 168
 169         case PTRACE_POKEUSR:    /* write the word at location addr in the USER area */
 170                 if (addr & 3)
 171                         goto out_eio;
 172                 addr >>= 2;     /* temporary hack. */
 173
 174                 if (addr == PT_SR) {
 175                         data &= SR_MASK;
 176                         data <<= 16;
 177                         data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 178                 } else if (addr >= 0 && addr < 19) {
 179                         if (put_reg(child, addr, data))
 180                                 goto out_eio;
 181                 } else if (addr >= 21 && addr < 48) {
 182                         /* Convert long double format
 183                          * into internal fpu reg representation
 184                          */
 185                         if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) {
 186                                 data = (unsigned long)data << 15;
 187                                 data = (data & 0xffff0000) |
 188                                        ((data & 0x0000ffff) >> 1);
 189                         }
 190                         child->thread.fp[addr - 21] = data;
 191                 } else
 192                         goto out_eio;
 193                 break;
 194
 195         case PTRACE_SYSCALL:    /* continue and stop at next (return from) syscall */
 196         case PTRACE_CONT:       /* restart after signal. */
 197                 if (!valid_signal(data))
 198                         goto out_eio;
 199
 200                 if (request == PTRACE_SYSCALL)
 201                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 202                 else
 203                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 204                 child->exit_code = data;
 205                 singlestep_disable(child);
 206                 wake_up_process(child);
 207                 break;
 208
 209         /*
 210          * make the child exit.  Best I can do is send it a sigkill.
 211          * perhaps it should be put in the status that it wants to
 212          * exit.
 213          */
 214         case PTRACE_KILL:
 215                 if (child->exit_state == EXIT_ZOMBIE) /* already dead */
 216                         break;
 217                 child->exit_code = SIGKILL;
 218                 singlestep_disable(child);
 219                 wake_up_process(child);
 220                 break;
 221
 222         case PTRACE_SINGLESTEP: /* set the trap flag. */
 223                 if (!valid_signal(data))
 224                         goto out_eio;
 225
 226                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 227                 tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
 228                 put_reg(child, PT_SR, tmp);
 229                 set_tsk_thread_flag(child, TIF_DELAYED_TRACE);
 230
 231                 child->exit_code = data;
 232                 /* give it a chance to run. */
 233                 wake_up_process(child);
 234                 break;
 235
 236         case PTRACE_DETACH:     /* detach a process that was attached. */
 237                 ret = ptrace_detach(child, data);
 238                 break;
 239
 240         case PTRACE_GETREGS:    /* Get all gp regs from the child. */
 241                 for (i = 0; i < 19; i++) {
 242                         tmp = get_reg(child, i);
 243                         if (i == PT_SR)
 244                                 tmp >>= 16;
 245                         ret = put_user(tmp, (unsigned long *)data);
 246                         if (ret)
 247                                 break;
 248                         data += sizeof(long);
 249                 }
 250                 break;
 251
 252         case PTRACE_SETREGS:    /* Set all gp regs in the child. */
 253                 for (i = 0; i < 19; i++) {
 254                         ret = get_user(tmp, (unsigned long *)data);
 255                         if (ret)
 256                                 break;
 257                         if (i == PT_SR) {
 258                                 tmp &= SR_MASK;
 259                                 tmp <<= 16;
 260                                 tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 261                         }
 262                         put_reg(child, i, tmp);
 263                         data += sizeof(long);
 264                 }
 265                 break;
 266
 267         case PTRACE_GETFPREGS:  /* Get the child FPU state. */
 268                 if (copy_to_user((void *)data, &child->thread.fp,
 269                                  sizeof(struct user_m68kfp_struct)))
 270                         ret = -EFAULT;
 271                 break;
 272
 273         case PTRACE_SETFPREGS:  /* Set the child FPU state. */
 274                 if (copy_from_user(&child->thread.fp, (void *)data,
 275                                    sizeof(struct user_m68kfp_struct)))
 276                         ret = -EFAULT;
 277                 break;
 278
 279         default:
 280                 ret = ptrace_request(child, request, addr, data);
 281                 break;
 282         }
 283
 284         return ret;
 285 out_eio:
 286         return -EIO;
 287 }
 288
 289 asmlinkage void syscall_trace(void)
 290 {
 291         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 292                                  ? 0x80 : 0));
 293         /*
 294          * this isn't the same as continuing with a signal, but it will do
 295          * for normal use.  strace only continues with a signal if the
 296          * stopping signal is not SIGTRAP.  -brl
 297          */
 298         if (current->exit_code) {
 299                 send_sig(current->exit_code, current, 1);
 300                 current->exit_code = 0;
 301         }
 302 }