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