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 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 void user_enable_block_step(struct task_struct *child)
 149 {
 150         unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
 151         put_reg(child, PT_SR, tmp | T0_BIT);
 152 }
 153
 154 void user_disable_single_step(struct task_struct *child)
 155 {
 156         singlestep_disable(child);
 157 }
 158
 159 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 160 {
 161         unsigned long tmp;
 162         int i, ret = 0;
 163
 164         switch (request) {
 165         /* read the word at location addr in the USER area. */
 166         case PTRACE_PEEKUSR:
 167                 if (addr & 3)
 168                         goto out_eio;
 169                 addr >>= 2;     /* temporary hack. */
 170
 171                 if (addr >= 0 && addr < 19) {
 172                         tmp = get_reg(child, addr);
 173                 } else if (addr >= 21 && addr < 49) {
 174                         tmp = child->thread.fp[addr - 21];
 175                         /* Convert internal fpu reg representation
 176                          * into long double format
 177                          */
 178                         if (FPU_IS_EMU && (addr < 45) && !(addr % 3))
 179                                 tmp = ((tmp & 0xffff0000) << 15) |
 180                                       ((tmp & 0x0000ffff) << 16);
 181                 } else
 182                         goto out_eio;
 183                 ret = put_user(tmp, (unsigned long *)data);
 184                 break;
 185
 186         case PTRACE_POKEUSR:    /* write the word at location addr in the USER area */
 187                 if (addr & 3)
 188                         goto out_eio;
 189                 addr >>= 2;     /* temporary hack. */
 190
 191                 if (addr == PT_SR) {
 192                         data &= SR_MASK;
 193                         data |= get_reg(child, PT_SR) & ~SR_MASK;
 194                 }
 195                 if (addr >= 0 && addr < 19) {
 196                         if (put_reg(child, addr, data))
 197                                 goto out_eio;
 198                 } else if (addr >= 21 && addr < 48) {
 199                         /* Convert long double format
 200                          * into internal fpu reg representation
 201                          */
 202                         if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) {
 203                                 data = (unsigned long)data << 15;
 204                                 data = (data & 0xffff0000) |
 205                                        ((data & 0x0000ffff) >> 1);
 206                         }
 207                         child->thread.fp[addr - 21] = data;
 208                 } else
 209                         goto out_eio;
 210                 break;
 211
 212         case PTRACE_GETREGS:    /* Get all gp regs from the child. */
 213                 for (i = 0; i < 19; i++) {
 214                         tmp = get_reg(child, i);
 215                         ret = put_user(tmp, (unsigned long *)data);
 216                         if (ret)
 217                                 break;
 218                         data += sizeof(long);
 219                 }
 220                 break;
 221
 222         case PTRACE_SETREGS:    /* Set all gp regs in the child. */
 223                 for (i = 0; i < 19; i++) {
 224                         ret = get_user(tmp, (unsigned long *)data);
 225                         if (ret)
 226                                 break;
 227                         if (i == PT_SR) {
 228                                 tmp &= SR_MASK;
 229                                 tmp |= get_reg(child, PT_SR) & ~SR_MASK;
 230                         }
 231                         put_reg(child, i, tmp);
 232                         data += sizeof(long);
 233                 }
 234                 break;
 235
 236         case PTRACE_GETFPREGS:  /* Get the child FPU state. */
 237                 if (copy_to_user((void *)data, &child->thread.fp,
 238                                  sizeof(struct user_m68kfp_struct)))
 239                         ret = -EFAULT;
 240                 break;
 241
 242         case PTRACE_SETFPREGS:  /* Set the child FPU state. */
 243                 if (copy_from_user(&child->thread.fp, (void *)data,
 244                                    sizeof(struct user_m68kfp_struct)))
 245                         ret = -EFAULT;
 246                 break;
 247
 248         default:
 249                 ret = ptrace_request(child, request, addr, data);
 250                 break;
 251         }
 252
 253         return ret;
 254 out_eio:
 255         return -EIO;
 256 }
 257
 258 asmlinkage void syscall_trace(void)
 259 {
 260         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 261                                  ? 0x80 : 0));
 262         /*
 263          * this isn't the same as continuing with a signal, but it will do
 264          * for normal use.  strace only continues with a signal if the
 265          * stopping signal is not SIGTRAP.  -brl
 266          */
 267         if (current->exit_code) {
 268                 send_sig(current->exit_code, current, 1);
 269                 current->exit_code = 0;
 270         }
 271 }