arch/m68knommu/kernel/ptrace.c

   1 /*
   2  *  linux/arch/m68knommu/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         PT_REG(d1), PT_REG(d2), PT_REG(d3), PT_REG(d4),
  49         PT_REG(d5), SW_REG(d6), SW_REG(d7), PT_REG(a0),
  50         PT_REG(a1), PT_REG(a2), SW_REG(a3), SW_REG(a4),
  51         SW_REG(a5), SW_REG(a6), PT_REG(d0), -1,
  52         PT_REG(orig_d0), PT_REG(sr), PT_REG(pc),
  53 };
  54
  55 /*
  56  * Get contents of register REGNO in task TASK.
  57  */
  58 static inline long get_reg(struct task_struct *task, int regno)
  59 {
  60         unsigned long *addr;
  61
  62         if (regno == PT_USP)
  63                 addr = &task->thread.usp;
  64         else if (regno < ARRAY_SIZE(regoff))
  65                 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
  66         else
  67                 return 0;
  68         return *addr;
  69 }
  70
  71 /*
  72  * Write contents of register REGNO in task TASK.
  73  */
  74 static inline int put_reg(struct task_struct *task, int regno,
  75                           unsigned long data)
  76 {
  77         unsigned long *addr;
  78
  79         if (regno == PT_USP)
  80                 addr = &task->thread.usp;
  81         else if (regno < ARRAY_SIZE(regoff))
  82                 addr = (unsigned long *) (task->thread.esp0 + regoff[regno]);
  83         else
  84                 return -1;
  85         *addr = data;
  86         return 0;
  87 }
  88
  89 /*
  90  * Called by kernel/ptrace.c when detaching..
  91  *
  92  * Make sure the single step bit is not set.
  93  */
  94 void ptrace_disable(struct task_struct *child)
  95 {
  96         unsigned long tmp;
  97         /* make sure the single step bit is not set. */
  98         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
  99         put_reg(child, PT_SR, tmp);
 100 }
 101
 102 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 103 {
 104         int ret;
 105
 106         switch (request) {
 107                 /* when I and D space are separate, these will need to be fixed. */
 108                 case PTRACE_PEEKTEXT: /* read word at location addr. */
 109                 case PTRACE_PEEKDATA: {
 110                         unsigned long tmp;
 111                         int copied;
 112
 113                         copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 114                         ret = -EIO;
 115                         if (copied != sizeof(tmp))
 116                                 break;
 117                         ret = put_user(tmp,(unsigned long *) data);
 118                         break;
 119                 }
 120
 121                 /* read the word at location addr in the USER area. */
 122                 case PTRACE_PEEKUSR: {
 123                         unsigned long tmp;
 124
 125                         ret = -EIO;
 126                         if ((addr & 3) || addr < 0 ||
 127                             addr > sizeof(struct user) - 3)
 128                                 break;
 129
 130                         tmp = 0;  /* Default return condition */
 131                         addr = addr >> 2; /* temporary hack. */
 132                         ret = -EIO;
 133                         if (addr < 19) {
 134                                 tmp = get_reg(child, addr);
 135                                 if (addr == PT_SR)
 136                                         tmp >>= 16;
 137                         } else if (addr >= 21 && addr < 49) {
 138                                 tmp = child->thread.fp[addr - 21];
 139 #ifdef CONFIG_M68KFPU_EMU
 140                                 /* Convert internal fpu reg representation
 141                                  * into long double format
 142                                  */
 143                                 if (FPU_IS_EMU && (addr < 45) && !(addr % 3))
 144                                         tmp = ((tmp & 0xffff0000) << 15) |
 145                                               ((tmp & 0x0000ffff) << 16);
 146 #endif
 147                         } else if (addr == 49) {
 148                                 tmp = child->mm->start_code;
 149                         } else if (addr == 50) {
 150                                 tmp = child->mm->start_data;
 151                         } else if (addr == 51) {
 152                                 tmp = child->mm->end_code;
 153                         } else
 154                                 break;
 155                         ret = put_user(tmp,(unsigned long *) data);
 156                         break;
 157                 }
 158
 159                 /* when I and D space are separate, this will have to be fixed. */
 160                 case PTRACE_POKETEXT: /* write the word at location addr. */
 161                 case PTRACE_POKEDATA:
 162                         ret = 0;
 163                         if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 164                                 break;
 165                         ret = -EIO;
 166                         break;
 167
 168                 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 169                         ret = -EIO;
 170                         if ((addr & 3) || addr < 0 ||
 171                             addr > sizeof(struct user) - 3)
 172                                 break;
 173
 174                         addr = addr >> 2; /* temporary hack. */
 175
 176                         if (addr == PT_SR) {
 177                                 data &= SR_MASK;
 178                                 data <<= 16;
 179                                 data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 180                         }
 181                         if (addr < 19) {
 182                                 if (put_reg(child, addr, data))
 183                                         break;
 184                                 ret = 0;
 185                                 break;
 186                         }
 187                         if (addr >= 21 && addr < 48)
 188                         {
 189 #ifdef CONFIG_M68KFPU_EMU
 190                                 /* Convert long double format
 191                                  * into internal fpu reg representation
 192                                  */
 193                                 if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) {
 194                                         data = (unsigned long)data << 15;
 195                                         data = (data & 0xffff0000) |
 196                                                ((data & 0x0000ffff) >> 1);
 197                                 }
 198 #endif
 199                                 child->thread.fp[addr - 21] = data;
 200                                 ret = 0;
 201                         }
 202                         break;
 203
 204                 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 205                 case PTRACE_CONT: { /* restart after signal. */
 206                         long tmp;
 207
 208                         ret = -EIO;
 209                         if (!valid_signal(data))
 210                                 break;
 211                         if (request == PTRACE_SYSCALL)
 212                                 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 213                         else
 214                                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 215                         child->exit_code = data;
 216                         /* make sure the single step bit is not set. */
 217                         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 218                         put_reg(child, PT_SR, tmp);
 219                         wake_up_process(child);
 220                         ret = 0;
 221                         break;
 222                 }
 223
 224                 /*
 225                  * make the child exit.  Best I can do is send it a sigkill.
 226                  * perhaps it should be put in the status that it wants to
 227                  * exit.
 228                  */
 229                 case PTRACE_KILL: {
 230                         long tmp;
 231
 232                         ret = 0;
 233                         if (child->exit_state == EXIT_ZOMBIE) /* already dead */
 234                                 break;
 235                         child->exit_code = SIGKILL;
 236                         /* make sure the single step bit is not set. */
 237                         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 238                         put_reg(child, PT_SR, tmp);
 239                         wake_up_process(child);
 240                         break;
 241                 }
 242
 243                 case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 244                         long tmp;
 245
 246                         ret = -EIO;
 247                         if (!valid_signal(data))
 248                                 break;
 249                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 250                         tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
 251                         put_reg(child, PT_SR, tmp);
 252
 253                         child->exit_code = data;
 254                         /* give it a chance to run. */
 255                         wake_up_process(child);
 256                         ret = 0;
 257                         break;
 258                 }
 259
 260                 case PTRACE_DETACH:     /* detach a process that was attached. */
 261                         ret = ptrace_detach(child, data);
 262                         break;
 263
 264                 case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 265                         int i;
 266                         unsigned long tmp;
 267                         for (i = 0; i < 19; i++) {
 268                             tmp = get_reg(child, i);
 269                             if (i == PT_SR)
 270                                 tmp >>= 16;
 271                             if (put_user(tmp, (unsigned long *) data)) {
 272                                 ret = -EFAULT;
 273                                 break;
 274                             }
 275                             data += sizeof(long);
 276                         }
 277                         ret = 0;
 278                         break;
 279                 }
 280
 281                 case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 282                         int i;
 283                         unsigned long tmp;
 284                         for (i = 0; i < 19; i++) {
 285                             if (get_user(tmp, (unsigned long *) data)) {
 286                                 ret = -EFAULT;
 287                                 break;
 288                             }
 289                             if (i == PT_SR) {
 290                                 tmp &= SR_MASK;
 291                                 tmp <<= 16;
 292                                 tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 293                             }
 294                             put_reg(child, i, tmp);
 295                             data += sizeof(long);
 296                         }
 297                         ret = 0;
 298                         break;
 299                 }
 300
 301 #ifdef PTRACE_GETFPREGS
 302                 case PTRACE_GETFPREGS: { /* Get the child FPU state. */
 303                         ret = 0;
 304                         if (copy_to_user((void *)data, &child->thread.fp,
 305                                          sizeof(struct user_m68kfp_struct)))
 306                                 ret = -EFAULT;
 307                         break;
 308                 }
 309 #endif
 310
 311 #ifdef PTRACE_SETFPREGS
 312                 case PTRACE_SETFPREGS: { /* Set the child FPU state. */
 313                         ret = 0;
 314                         if (copy_from_user(&child->thread.fp, (void *)data,
 315                                            sizeof(struct user_m68kfp_struct)))
 316                                 ret = -EFAULT;
 317                         break;
 318                 }
 319 #endif
 320
 321                 default:
 322                         ret = -EIO;
 323                         break;
 324         }
 325         return ret;
 326 }
 327
 328 asmlinkage void syscall_trace(void)
 329 {
 330         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 331                 return;
 332         if (!(current->ptrace & PT_PTRACED))
 333                 return;
 334         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 335                                  ? 0x80 : 0));
 336         /*
 337          * this isn't the same as continuing with a signal, but it will do
 338          * for normal use.  strace only continues with a signal if the
 339          * stopping signal is not SIGTRAP.  -brl
 340          */
 341         if (current->exit_code) {
 342                 send_sig(current->exit_code, current, 1);
 343                 current->exit_code = 0;
 344         }
 345 }