arch/nios2nommu/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
  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 0x00000000
  36
  37 /* Find the stack offset for a register, relative to thread.ksp. */
  38 #define PT_REG(reg)     ((long)&((struct pt_regs *)0)->reg)
  39 #define SW_REG(reg)     ((long)&((struct switch_stack *)0)->reg \
  40                          - sizeof(struct switch_stack))
  41 /* Mapping from PT_xxx to the stack offset at which the register is
  42    saved.  Notice that usp has no stack-slot and needs to be treated
  43    specially (see get_reg/put_reg below). */
  44 static int regoff[] = {
  45         -1, PT_REG(r1), PT_REG(r2), PT_REG(r3), PT_REG(r4),
  46         PT_REG(r5), PT_REG(r6), PT_REG(r7), PT_REG(r8),
  47         PT_REG(r9), PT_REG(r10), PT_REG(r11), PT_REG(r12),
  48         PT_REG(r13), PT_REG(r14), PT_REG(r15), SW_REG(r16),
  49         SW_REG(r17), SW_REG(r18), SW_REG(r19), SW_REG(r20),
  50         SW_REG(r21), SW_REG(r22), SW_REG(r23), -1, -1,
  51         PT_REG(gp), PT_REG(sp), -1, -1, PT_REG(ra), -1,
  52         PT_REG(estatus), -1, -1, -1
  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 == PTR_R0)
  63                 return 0;
  64         else if (regno == PTR_BA)
  65                 return 0;
  66         else if (regno == PTR_STATUS)
  67                 return 0;
  68         else if (regno == PTR_IENABLE)
  69                 return 0;
  70         else if (regno == PTR_IPENDING)
  71                 return 0;
  72         else if (regno < sizeof(regoff)/sizeof(regoff[0]))
  73                 addr = (unsigned long *)(task->thread.kregs + regoff[regno]);
  74         else
  75                 return 0;
  76         return *addr;
  77 }
  78
  79 /*
  80  * Write contents of register REGNO in task TASK.
  81  */
  82 static inline int put_reg(struct task_struct *task, int regno,
  83                           unsigned long data)
  84 {
  85         unsigned long *addr;
  86
  87         if (regno == PTR_R0)
  88                 return -1;
  89         else if (regno == PTR_BA)
  90                 return -1;
  91         else if (regno == PTR_STATUS)
  92                 return -1;
  93         else if (regno == PTR_IENABLE)
  94                 return -1;
  95         else if (regno == PTR_IPENDING)
  96                 return -1;
  97         else if (regno < sizeof(regoff)/sizeof(regoff[0]))
  98                 addr = (unsigned long *) (task->thread.kregs + regoff[regno]);
  99         else
 100                 return -1;
 101         *addr = data;
 102         return 0;
 103 }
 104
 105 /*
 106  * Called by kernel/ptrace.c when detaching..
 107  *
 108  * Nothing special to do here, no processor debug support.
 109  */
 110 void ptrace_disable(struct task_struct *child)
 111 {
 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                 /* when I and D space are separate, these will need to be fixed. */
 120                 case PTRACE_PEEKTEXT: /* read word at location addr. */
 121                 case PTRACE_PEEKDATA: {
 122                         unsigned long tmp;
 123                         int copied;
 124
 125                         copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 126                         ret = -EIO;
 127                         if (copied != sizeof(tmp))
 128                                 break;
 129                         ret = put_user(tmp,(unsigned long *) data);
 130                         break;
 131                 }
 132
 133                 /* read the word at location addr in the USER area. */
 134                 case PTRACE_PEEKUSR: {
 135                         unsigned long tmp;
 136
 137                         ret = -EIO;
 138                         if ((addr & 3) || addr < 0 ||
 139                             addr > sizeof(struct user) - 3)
 140                                 break;
 141
 142                         tmp = 0;  /* Default return condition */
 143                         addr = addr >> 2; /* temporary hack. */
 144                         ret = -EIO;
 145                         if (addr < 19) {
 146                                 tmp = get_reg(child, addr);
 147 #if 0 // No FPU stuff
 148                         } else if (addr >= 21 && addr < 49) {
 149                                 tmp = child->thread.fp[addr - 21];
 150 #ifdef CONFIG_M68KFPU_EMU
 151                                 /* Convert internal fpu reg representation
 152                                  * into long double format
 153                                  */
 154                                 if (FPU_IS_EMU && (addr < 45) && !(addr % 3))
 155                                         tmp = ((tmp & 0xffff0000) << 15) |
 156                                               ((tmp & 0x0000ffff) << 16);
 157 #endif
 158 #endif
 159                         } else if (addr == 49) {
 160                                 tmp = child->mm->start_code;
 161                         } else if (addr == 50) {
 162                                 tmp = child->mm->start_data;
 163                         } else if (addr == 51) {
 164                                 tmp = child->mm->end_code;
 165                         } else
 166                                 break;
 167                         ret = put_user(tmp,(unsigned long *) data);
 168                         break;
 169                 }
 170
 171                 /* when I and D space are separate, this will have to be fixed. */
 172                 case PTRACE_POKETEXT: /* write the word at location addr. */
 173                 case PTRACE_POKEDATA:
 174                         ret = 0;
 175                         if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 176                                 break;
 177                         ret = -EIO;
 178                         break;
 179
 180                 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 181                         ret = -EIO;
 182                         if ((addr & 3) || addr < 0 ||
 183                             addr > sizeof(struct user) - 3)
 184                                 break;
 185
 186                         addr = addr >> 2; /* temporary hack. */
 187
 188                         if (addr == PTR_ESTATUS) {
 189                                 data &= SR_MASK;
 190                                 data |= get_reg(child, PTR_ESTATUS) & ~(SR_MASK);
 191                         }
 192                         if (addr < 19) {
 193                                 if (put_reg(child, addr, data))
 194                                         break;
 195                                 ret = 0;
 196                                 break;
 197                         }
 198 #if 0 // No FPU stuff
 199                         if (addr >= 21 && addr < 48)
 200                         {
 201 #ifdef CONFIG_M68KFPU_EMU
 202                                 /* Convert long double format
 203                                  * into internal fpu reg representation
 204                                  */
 205                                 if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) {
 206                                         data = (unsigned long)data << 15;
 207                                         data = (data & 0xffff0000) |
 208                                                ((data & 0x0000ffff) >> 1);
 209                                 }
 210 #endif
 211                                 child->thread.fp[addr - 21] = data;
 212                                 ret = 0;
 213                         }
 214 #endif
 215                         break;
 216
 217                 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 218                 case PTRACE_CONT: { /* restart after signal. */
 219
 220                         ret = -EIO;
 221                         if ((unsigned long) data > _NSIG)
 222                                 break;
 223                         if (request == PTRACE_SYSCALL)
 224                                 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 225                         else
 226                                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 227                         child->exit_code = data;
 228                         wake_up_process(child);
 229                         ret = 0;
 230                         break;
 231                 }
 232
 233                 /*
 234                  * make the child exit.  Best I can do is send it a sigkill.
 235                  * perhaps it should be put in the status that it wants to
 236                  * exit.
 237                  */
 238                 case PTRACE_KILL: {
 239
 240                         ret = 0;
 241                         if (child->state == EXIT_ZOMBIE) /* already dead */
 242                                 break;
 243                         child->exit_code = SIGKILL;
 244                         wake_up_process(child);
 245                         break;
 246                 }
 247
 248                 /*
 249                  * Single stepping requires placing break instructions in
 250                  * the code to break back. If you are stepping through a
 251                  * conditional branch you need to decode the test and put
 252                  * the break in the correct location.
 253                  */
 254                 case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 255
 256                         ret = -EIO;
 257                         if ((unsigned long) data > _NSIG)
 258                                 break;
 259                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 260
 261                         child->exit_code = data;
 262                         /* give it a chance to run. */
 263                         wake_up_process(child);
 264                         ret = 0;
 265                         break;
 266                 }
 267
 268                 case PTRACE_DETACH:     /* detach a process that was attached. */
 269                         ret = ptrace_detach(child, data);
 270                         break;
 271
 272                 case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 273                         int i;
 274                         unsigned long tmp;
 275                         for (i = 0; i < 19; i++) {
 276                             tmp = get_reg(child, i);
 277                             if (put_user(tmp, (unsigned long *) data)) {
 278                                 ret = -EFAULT;
 279                                 break;
 280                             }
 281                             data += sizeof(long);
 282                         }
 283                         ret = 0;
 284                         break;
 285                 }
 286
 287                 case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 288                         int i;
 289                         unsigned long tmp;
 290                         for (i = 0; i < 19; i++) {
 291                             if (get_user(tmp, (unsigned long *) data)) {
 292                                 ret = -EFAULT;
 293                                 break;
 294                             }
 295                             if (i == PTR_ESTATUS) {
 296                                 tmp &= SR_MASK;
 297                                 tmp |= get_reg(child, PTR_ESTATUS) & ~(SR_MASK);
 298                             }
 299                             put_reg(child, i, tmp);
 300                             data += sizeof(long);
 301                         }
 302                         ret = 0;
 303                         break;
 304                 }
 305
 306 #ifdef PTRACE_GETFPREGS
 307                 case PTRACE_GETFPREGS: { /* Get the child FPU state. */
 308                         ret = 0;
 309                         if (copy_to_user((void *)data, &child->thread.fp,
 310                                          sizeof(struct user_m68kfp_struct)))
 311                                 ret = -EFAULT;
 312                         break;
 313                 }
 314 #endif
 315
 316 #ifdef PTRACE_SETFPREGS
 317                 case PTRACE_SETFPREGS: { /* Set the child FPU state. */
 318                         ret = 0;
 319                         if (copy_from_user(&child->thread.fp, (void *)data,
 320                                            sizeof(struct user_m68kfp_struct)))
 321                                 ret = -EFAULT;
 322                         break;
 323                 }
 324 #endif
 325
 326                 default:
 327                         ret = -EIO;
 328                         break;
 329         }
 330         return ret;
 331 }
 332
 333 asmlinkage void syscall_trace(void)
 334 {
 335         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 336                 return;
 337         if (!(current->ptrace & PT_PTRACED))
 338                 return;
 339         current->exit_code = SIGTRAP;
 340         current->state = TASK_STOPPED;
 341         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 342                                  ? 0x80 : 0));
 343         /*
 344          * this isn't the same as continuing with a signal, but it will do
 345          * for normal use.  strace only continues with a signal if the
 346          * stopping signal is not SIGTRAP.  -brl
 347          */
 348         if (current->exit_code) {
 349                 send_sig(current->exit_code, current, 1);
 350                 current->exit_code = 0;
 351         }
 352 }