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/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         PT_REG(d1), PT_REG(d2), PT_REG(d3), PT_REG(d4),
  51         PT_REG(d5), SW_REG(d6), SW_REG(d7), PT_REG(a0),
  52         PT_REG(a1), PT_REG(a2), SW_REG(a3), SW_REG(a4),
  53         SW_REG(a5), SW_REG(a6), PT_REG(d0), -1,
  54         PT_REG(orig_d0), PT_REG(sr), PT_REG(pc),
  55 };
  56
  57 /*
  58  * Get contents of register REGNO in task TASK.
  59  */
  60 static inline long get_reg(struct task_struct *task, int regno)
  61 {
  62         unsigned long *addr;
  63
  64         if (regno == PT_USP)
  65                 addr = &task->thread.usp;
  66         else if (regno < sizeof(regoff)/sizeof(regoff[0]))
  67                 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
  68         else
  69                 return 0;
  70         return *addr;
  71 }
  72
  73 /*
  74  * Write contents of register REGNO in task TASK.
  75  */
  76 static inline int put_reg(struct task_struct *task, int regno,
  77                           unsigned long data)
  78 {
  79         unsigned long *addr;
  80
  81         if (regno == PT_USP)
  82                 addr = &task->thread.usp;
  83         else if (regno < sizeof(regoff)/sizeof(regoff[0]))
  84                 addr = (unsigned long *) (task->thread.esp0 + regoff[regno]);
  85         else
  86                 return -1;
  87         *addr = data;
  88         return 0;
  89 }
  90
  91 /*
  92  * Called by kernel/ptrace.c when detaching..
  93  *
  94  * Make sure the single step bit is not set.
  95  */
  96 void ptrace_disable(struct task_struct *child)
  97 {
  98         unsigned long tmp;
  99         /* make sure the single step bit is not set. */
 100         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 101         put_reg(child, PT_SR, tmp);
 102 }
 103
 104 long arch_ptrace(truct task_struct *child, long request, long addr, long data)
 105 {
 106         int ret;
 107
 108         switch (request) {
 109                 /* when I and D space are separate, these will need to be fixed. */
 110                 case PTRACE_PEEKTEXT: /* read word at location addr. */
 111                 case PTRACE_PEEKDATA: {
 112                         unsigned long tmp;
 113                         int copied;
 114
 115                         copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 116                         ret = -EIO;
 117                         if (copied != sizeof(tmp))
 118                                 break;
 119                         ret = put_user(tmp,(unsigned long *) data);
 120                         break;
 121                 }
 122
 123                 /* read the word at location addr in the USER area. */
 124                 case PTRACE_PEEKUSR: {
 125                         unsigned long tmp;
 126
 127                         ret = -EIO;
 128                         if ((addr & 3) || addr < 0 ||
 129                             addr > sizeof(struct user) - 3)
 130                                 break;
 131
 132                         tmp = 0;  /* Default return condition */
 133                         addr = addr >> 2; /* temporary hack. */
 134                         ret = -EIO;
 135                         if (addr < 19) {
 136                                 tmp = get_reg(child, addr);
 137                                 if (addr == PT_SR)
 138                                         tmp >>= 16;
 139                         } else if (addr >= 21 && addr < 49) {
 140                                 tmp = child->thread.fp[addr - 21];
 141 #ifdef CONFIG_M68KFPU_EMU
 142                                 /* Convert internal fpu reg representation
 143                                  * into long double format
 144                                  */
 145                                 if (FPU_IS_EMU && (addr < 45) && !(addr % 3))
 146                                         tmp = ((tmp & 0xffff0000) << 15) |
 147                                               ((tmp & 0x0000ffff) << 16);
 148 #endif
 149                         } else if (addr == 49) {
 150                                 tmp = child->mm->start_code;
 151                         } else if (addr == 50) {
 152                                 tmp = child->mm->start_data;
 153                         } else if (addr == 51) {
 154                                 tmp = child->mm->end_code;
 155                         } else
 156                                 break;
 157                         ret = put_user(tmp,(unsigned long *) data);
 158                         break;
 159                 }
 160
 161                 /* when I and D space are separate, this will have to be fixed. */
 162                 case PTRACE_POKETEXT: /* write the word at location addr. */
 163                 case PTRACE_POKEDATA:
 164                         ret = 0;
 165                         if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 166                                 break;
 167                         ret = -EIO;
 168                         break;
 169
 170                 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 171                         ret = -EIO;
 172                         if ((addr & 3) || addr < 0 ||
 173                             addr > sizeof(struct user) - 3)
 174                                 break;
 175
 176                         addr = addr >> 2; /* temporary hack. */
 177
 178                         if (addr == PT_SR) {
 179                                 data &= SR_MASK;
 180                                 data <<= 16;
 181                                 data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 182                         }
 183                         if (addr < 19) {
 184                                 if (put_reg(child, addr, data))
 185                                         break;
 186                                 ret = 0;
 187                                 break;
 188                         }
 189                         if (addr >= 21 && addr < 48)
 190                         {
 191 #ifdef CONFIG_M68KFPU_EMU
 192                                 /* Convert long double format
 193                                  * into internal fpu reg representation
 194                                  */
 195                                 if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) {
 196                                         data = (unsigned long)data << 15;
 197                                         data = (data & 0xffff0000) |
 198                                                ((data & 0x0000ffff) >> 1);
 199                                 }
 200 #endif
 201                                 child->thread.fp[addr - 21] = data;
 202                                 ret = 0;
 203                         }
 204                         break;
 205
 206                 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 207                 case PTRACE_CONT: { /* restart after signal. */
 208                         long tmp;
 209
 210                         ret = -EIO;
 211                         if (!valid_signal(data))
 212                                 break;
 213                         if (request == PTRACE_SYSCALL)
 214                                 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 215                         else
 216                                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 217                         child->exit_code = data;
 218                         /* make sure the single step bit is not set. */
 219                         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 220                         put_reg(child, PT_SR, tmp);
 221                         wake_up_process(child);
 222                         ret = 0;
 223                         break;
 224                 }
 225
 226                 /*
 227                  * make the child exit.  Best I can do is send it a sigkill.
 228                  * perhaps it should be put in the status that it wants to
 229                  * exit.
 230                  */
 231                 case PTRACE_KILL: {
 232                         long tmp;
 233
 234                         ret = 0;
 235                         if (child->exit_state == EXIT_ZOMBIE) /* already dead */
 236                                 break;
 237                         child->exit_code = SIGKILL;
 238                         /* make sure the single step bit is not set. */
 239                         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 240                         put_reg(child, PT_SR, tmp);
 241                         wake_up_process(child);
 242                         break;
 243                 }
 244
 245                 case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 246                         long tmp;
 247
 248                         ret = -EIO;
 249                         if (!valid_signal(data))
 250                                 break;
 251                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 252                         tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
 253                         put_reg(child, PT_SR, tmp);
 254
 255                         child->exit_code = data;
 256                         /* give it a chance to run. */
 257                         wake_up_process(child);
 258                         ret = 0;
 259                         break;
 260                 }
 261
 262                 case PTRACE_DETACH:     /* detach a process that was attached. */
 263                         ret = ptrace_detach(child, data);
 264                         break;
 265
 266                 case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 267                         int i;
 268                         unsigned long tmp;
 269                         for (i = 0; i < 19; i++) {
 270                             tmp = get_reg(child, i);
 271                             if (i == PT_SR)
 272                                 tmp >>= 16;
 273                             if (put_user(tmp, (unsigned long *) data)) {
 274                                 ret = -EFAULT;
 275                                 break;
 276                             }
 277                             data += sizeof(long);
 278                         }
 279                         ret = 0;
 280                         break;
 281                 }
 282
 283                 case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 284                         int i;
 285                         unsigned long tmp;
 286                         for (i = 0; i < 19; i++) {
 287                             if (get_user(tmp, (unsigned long *) data)) {
 288                                 ret = -EFAULT;
 289                                 break;
 290                             }
 291                             if (i == PT_SR) {
 292                                 tmp &= SR_MASK;
 293                                 tmp <<= 16;
 294                                 tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 295                             }
 296                             put_reg(child, i, tmp);
 297                             data += sizeof(long);
 298                         }
 299                         ret = 0;
 300                         break;
 301                 }
 302
 303 #ifdef PTRACE_GETFPREGS
 304                 case PTRACE_GETFPREGS: { /* Get the child FPU state. */
 305                         ret = 0;
 306                         if (copy_to_user((void *)data, &child->thread.fp,
 307                                          sizeof(struct user_m68kfp_struct)))
 308                                 ret = -EFAULT;
 309                         break;
 310                 }
 311 #endif
 312
 313 #ifdef PTRACE_SETFPREGS
 314                 case PTRACE_SETFPREGS: { /* Set the child FPU state. */
 315                         ret = 0;
 316                         if (copy_from_user(&child->thread.fp, (void *)data,
 317                                            sizeof(struct user_m68kfp_struct)))
 318                                 ret = -EFAULT;
 319                         break;
 320                 }
 321 #endif
 322
 323                 default:
 324                         ret = -EIO;
 325                         break;
 326         }
 327         return ret;
 328 }
 329
 330 asmlinkage void syscall_trace(void)
 331 {
 332         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 333                 return;
 334         if (!(current->ptrace & PT_PTRACED))
 335                 return;
 336         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 337                                  ? 0x80 : 0));
 338         /*
 339          * this isn't the same as continuing with a signal, but it will do
 340          * for normal use.  strace only continues with a signal if the
 341          * stopping signal is not SIGTRAP.  -brl
 342          */
 343         if (current->exit_code) {
 344                 send_sig(current->exit_code, current, 1);
 345                 current->exit_code = 0;
 346         }
 347 }