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