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 #include <linux/tracehook.h>
  22
  23 #include <asm/uaccess.h>
  24 #include <asm/page.h>
  25 #include <asm/pgtable.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 0xC000
  39 #define T1_BIT 0x8000
  40 #define T0_BIT 0x4000
  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 const 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 < ARRAY_SIZE(regoff))
  81                 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
  82         else
  83                 return 0;
  84         /* Need to take stkadj into account. */
  85         if (regno == PT_SR || regno == PT_PC) {
  86                 long stkadj = *(long *)(task->thread.esp0 + PT_REG(stkadj));
  87                 addr = (unsigned long *) ((unsigned long)addr + stkadj);
  88                 /* The sr is actually a 16 bit register.  */
  89                 if (regno == PT_SR)
  90                         return *(unsigned short *)addr;
  91         }
  92         return *addr;
  93 }
  94
  95 /*
  96  * Write contents of register REGNO in task TASK.
  97  */
  98 static inline int put_reg(struct task_struct *task, int regno,
  99                           unsigned long data)
 100 {
 101         unsigned long *addr;
 102
 103         if (regno == PT_USP)
 104                 addr = &task->thread.usp;
 105         else if (regno < ARRAY_SIZE(regoff))
 106                 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
 107         else
 108                 return -1;
 109         /* Need to take stkadj into account. */
 110         if (regno == PT_SR || regno == PT_PC) {
 111                 long stkadj = *(long *)(task->thread.esp0 + PT_REG(stkadj));
 112                 addr = (unsigned long *) ((unsigned long)addr + stkadj);
 113                 /* The sr is actually a 16 bit register.  */
 114                 if (regno == PT_SR) {
 115                         *(unsigned short *)addr = data;
 116                         return 0;
 117                 }
 118         }
 119         *addr = data;
 120         return 0;
 121 }
 122
 123 /*
 124  * Make sure the single step bit is not set.
 125  */
 126 static inline void singlestep_disable(struct task_struct *child)
 127 {
 128         unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
 129         put_reg(child, PT_SR, tmp);
 130         clear_tsk_thread_flag(child, TIF_DELAYED_TRACE);
 131 }
 132
 133 /*
 134  * Called by kernel/ptrace.c when detaching..
 135  */
 136 void ptrace_disable(struct task_struct *child)
 137 {
 138         singlestep_disable(child);
 139 }
 140
 141 void user_enable_single_step(struct task_struct *child)
 142 {
 143         unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
 144         put_reg(child, PT_SR, tmp | T1_BIT);
 145         set_tsk_thread_flag(child, TIF_DELAYED_TRACE);
 146 }
 147
 148 #ifdef CONFIG_MMU
 149 void user_enable_block_step(struct task_struct *child)
 150 {
 151         unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
 152         put_reg(child, PT_SR, tmp | T0_BIT);
 153 }
 154 #endif
 155
 156 void user_disable_single_step(struct task_struct *child)
 157 {
 158         singlestep_disable(child);
 159 }
 160
 161 long arch_ptrace(struct task_struct *child, long request,
 162                  unsigned long addr, unsigned long data)
 163 {
 164         unsigned long tmp;
 165         int i, ret = 0;
 166         int regno = addr >> 2; /* temporary hack. */
 167         unsigned long __user *datap = (unsigned long __user *) data;
 168
 169         switch (request) {
 170         /* read the word at location addr in the USER area. */
 171         case PTRACE_PEEKUSR:
 172                 if (addr & 3)
 173                         goto out_eio;
 174
 175                 if (regno >= 0 && regno < 19) {
 176                         tmp = get_reg(child, regno);
 177                 } else if (regno >= 21 && regno < 49) {
 178                         tmp = child->thread.fp[regno - 21];
 179                         /* Convert internal fpu reg representation
 180                          * into long double format
 181                          */
 182                         if (FPU_IS_EMU && (regno < 45) && !(regno % 3))
 183                                 tmp = ((tmp & 0xffff0000) << 15) |
 184                                       ((tmp & 0x0000ffff) << 16);
 185 #ifndef CONFIG_MMU
 186                 } else if (regno == 49) {
 187                         tmp = child->mm->start_code;
 188                 } else if (regno == 50) {
 189                         tmp = child->mm->start_data;
 190                 } else if (regno == 51) {
 191                         tmp = child->mm->end_code;
 192 #endif
 193                 } else
 194                         goto out_eio;
 195                 ret = put_user(tmp, datap);
 196                 break;
 197
 198         case PTRACE_POKEUSR:
 199         /* write the word at location addr in the USER area */
 200                 if (addr & 3)
 201                         goto out_eio;
 202
 203                 if (regno == PT_SR) {
 204                         data &= SR_MASK;
 205                         data |= get_reg(child, PT_SR) & ~SR_MASK;
 206                 }
 207                 if (regno >= 0 && regno < 19) {
 208                         if (put_reg(child, regno, data))
 209                                 goto out_eio;
 210                 } else if (regno >= 21 && regno < 48) {
 211                         /* Convert long double format
 212                          * into internal fpu reg representation
 213                          */
 214                         if (FPU_IS_EMU && (regno < 45) && !(regno % 3)) {
 215                                 data <<= 15;
 216                                 data = (data & 0xffff0000) |
 217                                        ((data & 0x0000ffff) >> 1);
 218                         }
 219                         child->thread.fp[regno - 21] = data;
 220                 } else
 221                         goto out_eio;
 222                 break;
 223
 224         case PTRACE_GETREGS:    /* Get all gp regs from the child. */
 225                 for (i = 0; i < 19; i++) {
 226                         tmp = get_reg(child, i);
 227                         ret = put_user(tmp, datap);
 228                         if (ret)
 229                                 break;
 230                         datap++;
 231                 }
 232                 break;
 233
 234         case PTRACE_SETREGS:    /* Set all gp regs in the child. */
 235                 for (i = 0; i < 19; i++) {
 236                         ret = get_user(tmp, datap);
 237                         if (ret)
 238                                 break;
 239                         if (i == PT_SR) {
 240                                 tmp &= SR_MASK;
 241                                 tmp |= get_reg(child, PT_SR) & ~SR_MASK;
 242                         }
 243                         put_reg(child, i, tmp);
 244                         datap++;
 245                 }
 246                 break;
 247
 248         case PTRACE_GETFPREGS:  /* Get the child FPU state. */
 249                 if (copy_to_user(datap, &child->thread.fp,
 250                                  sizeof(struct user_m68kfp_struct)))
 251                         ret = -EFAULT;
 252                 break;
 253
 254         case PTRACE_SETFPREGS:  /* Set the child FPU state. */
 255                 if (copy_from_user(&child->thread.fp, datap,
 256                                    sizeof(struct user_m68kfp_struct)))
 257                         ret = -EFAULT;
 258                 break;
 259
 260         case PTRACE_GET_THREAD_AREA:
 261                 ret = put_user(task_thread_info(child)->tp_value, datap);
 262                 break;
 263
 264         default:
 265                 ret = ptrace_request(child, request, addr, data);
 266                 break;
 267         }
 268
 269         return ret;
 270 out_eio:
 271         return -EIO;
 272 }
 273
 274 asmlinkage void syscall_trace(void)
 275 {
 276         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 277                                  ? 0x80 : 0));
 278         /*
 279          * this isn't the same as continuing with a signal, but it will do
 280          * for normal use.  strace only continues with a signal if the
 281          * stopping signal is not SIGTRAP.  -brl
 282          */
 283         if (current->exit_code) {
 284                 send_sig(current->exit_code, current, 1);
 285                 current->exit_code = 0;
 286         }
 287 }
 288
 289 #if defined(CONFIG_COLDFIRE) || !defined(CONFIG_MMU)
 290 asmlinkage int syscall_trace_enter(void)
 291 {
 292         int ret = 0;
 293
 294         if (test_thread_flag(TIF_SYSCALL_TRACE))
 295                 ret = tracehook_report_syscall_entry(task_pt_regs(current));
 296         return ret;
 297 }
 298
 299 asmlinkage void syscall_trace_leave(void)
 300 {
 301         if (test_thread_flag(TIF_SYSCALL_TRACE))
 302                 tracehook_report_syscall_exit(task_pt_regs(current), 0);
 303 }
 304 #endif /* CONFIG_COLDFIRE */