arch/blackfin/kernel/ptrace.c

   1 /*
   2  * linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
   3  * these modifications are Copyright 2004-2009 Analog Devices Inc.
   4  *
   5  * Licensed under the GPL-2
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/sched.h>
  10 #include <linux/mm.h>
  11 #include <linux/smp.h>
  12 #include <linux/errno.h>
  13 #include <linux/ptrace.h>
  14 #include <linux/user.h>
  15 #include <linux/signal.h>
  16 #include <linux/uaccess.h>
  17
  18 #include <asm/page.h>
  19 #include <asm/pgtable.h>
  20 #include <asm/system.h>
  21 #include <asm/processor.h>
  22 #include <asm/asm-offsets.h>
  23 #include <asm/dma.h>
  24 #include <asm/fixed_code.h>
  25 #include <asm/cacheflush.h>
  26 #include <asm/mem_map.h>
  27
  28 #define TEXT_OFFSET 0
  29 /*
  30  * does not yet catch signals sent when the child dies.
  31  * in exit.c or in signal.c.
  32  */
  33
  34 /* determines which bits in the SYSCFG reg the user has access to. */
  35 /* 1 = access 0 = no access */
  36 #define SYSCFG_MASK 0x0007      /* SYSCFG reg */
  37 /* sets the trace bits. */
  38 #define TRACE_BITS 0x0001
  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
  43 /*
  44  * Get the address of the live pt_regs for the specified task.
  45  * These are saved onto the top kernel stack when the process
  46  * is not running.
  47  *
  48  * Note: if a user thread is execve'd from kernel space, the
  49  * kernel stack will not be empty on entry to the kernel, so
  50  * ptracing these tasks will fail.
  51  */
  52 static inline struct pt_regs *get_user_regs(struct task_struct *task)
  53 {
  54         return (struct pt_regs *)
  55             ((unsigned long)task_stack_page(task) +
  56              (THREAD_SIZE - sizeof(struct pt_regs)));
  57 }
  58
  59 /*
  60  * Get all user integer registers.
  61  */
  62 static inline int ptrace_getregs(struct task_struct *tsk, void __user *uregs)
  63 {
  64         struct pt_regs regs;
  65         memcpy(&regs, get_user_regs(tsk), sizeof(regs));
  66         regs.usp = tsk->thread.usp;
  67         return copy_to_user(uregs, &regs, sizeof(struct pt_regs)) ? -EFAULT : 0;
  68 }
  69
  70 /* Mapping from PT_xxx to the stack offset at which the register is
  71  * saved.  Notice that usp has no stack-slot and needs to be treated
  72  * specially (see get_reg/put_reg below).
  73  */
  74
  75 /*
  76  * Get contents of register REGNO in task TASK.
  77  */
  78 static inline long get_reg(struct task_struct *task, int regno)
  79 {
  80         unsigned char *reg_ptr;
  81
  82         struct pt_regs *regs =
  83             (struct pt_regs *)((unsigned long)task_stack_page(task) +
  84                                (THREAD_SIZE - sizeof(struct pt_regs)));
  85         reg_ptr = (char *)regs;
  86
  87         switch (regno) {
  88         case PT_USP:
  89                 return task->thread.usp;
  90         default:
  91                 if (regno <= 216)
  92                         return *(long *)(reg_ptr + regno);
  93         }
  94         /* slight mystery ... never seems to come here but kernel misbehaves without this code! */
  95
  96         printk(KERN_WARNING "Request to get for unknown register %d\n", regno);
  97         return 0;
  98 }
  99
 100 /*
 101  * Write contents of register REGNO in task TASK.
 102  */
 103 static inline int
 104 put_reg(struct task_struct *task, int regno, unsigned long data)
 105 {
 106         char *reg_ptr;
 107
 108         struct pt_regs *regs =
 109             (struct pt_regs *)((unsigned long)task_stack_page(task) +
 110                                (THREAD_SIZE - sizeof(struct pt_regs)));
 111         reg_ptr = (char *)regs;
 112
 113         switch (regno) {
 114         case PT_PC:
 115                 /*********************************************************************/
 116                 /* At this point the kernel is most likely in exception.             */
 117                 /* The RETX register will be used to populate the pc of the process. */
 118                 /*********************************************************************/
 119                 regs->retx = data;
 120                 regs->pc = data;
 121                 break;
 122         case PT_RETX:
 123                 break;          /* regs->retx = data; break; */
 124         case PT_USP:
 125                 regs->usp = data;
 126                 task->thread.usp = data;
 127                 break;
 128         default:
 129                 if (regno <= 216)
 130                         *(long *)(reg_ptr + regno) = data;
 131         }
 132         return 0;
 133 }
 134
 135 /*
 136  * check that an address falls within the bounds of the target process's memory mappings
 137  */
 138 static inline int is_user_addr_valid(struct task_struct *child,
 139                                      unsigned long start, unsigned long len)
 140 {
 141         struct vm_area_struct *vma;
 142         struct sram_list_struct *sraml;
 143
 144         /* overflow */
 145         if (start + len < start)
 146                 return -EIO;
 147
 148         vma = find_vma(child->mm, start);
 149         if (vma && start >= vma->vm_start && start + len <= vma->vm_end)
 150                         return 0;
 151
 152         for (sraml = child->mm->context.sram_list; sraml; sraml = sraml->next)
 153                 if (start >= (unsigned long)sraml->addr
 154                     && start + len < (unsigned long)sraml->addr + sraml->length)
 155                         return 0;
 156
 157         if (start >= FIXED_CODE_START && start + len < FIXED_CODE_END)
 158                 return 0;
 159
 160         return -EIO;
 161 }
 162
 163 void ptrace_enable(struct task_struct *child)
 164 {
 165         unsigned long tmp;
 166         tmp = get_reg(child, PT_SYSCFG) | (TRACE_BITS);
 167         put_reg(child, PT_SYSCFG, tmp);
 168 }
 169
 170 /*
 171  * Called by kernel/ptrace.c when detaching..
 172  *
 173  * Make sure the single step bit is not set.
 174  */
 175 void ptrace_disable(struct task_struct *child)
 176 {
 177         unsigned long tmp;
 178         /* make sure the single step bit is not set. */
 179         tmp = get_reg(child, PT_SYSCFG) & ~TRACE_BITS;
 180         put_reg(child, PT_SYSCFG, tmp);
 181 }
 182
 183 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 184 {
 185         int ret;
 186         unsigned long __user *datap = (unsigned long __user *)data;
 187         void *paddr = (void *)addr;
 188
 189         switch (request) {
 190                 /* when I and D space are separate, these will need to be fixed. */
 191         case PTRACE_PEEKDATA:
 192                 pr_debug("ptrace: PEEKDATA\n");
 193                 /* fall through */
 194         case PTRACE_PEEKTEXT:   /* read word at location addr. */
 195                 {
 196                         unsigned long tmp = 0;
 197                         int copied = 0, to_copy = sizeof(tmp);
 198
 199                         ret = -EIO;
 200                         pr_debug("ptrace: PEEKTEXT at addr 0x%08lx + %i\n", addr, to_copy);
 201                         if (is_user_addr_valid(child, addr, to_copy) < 0)
 202                                 break;
 203                         pr_debug("ptrace: user address is valid\n");
 204
 205                         switch (bfin_mem_access_type(addr, to_copy)) {
 206                         case BFIN_MEM_ACCESS_CORE:
 207                         case BFIN_MEM_ACCESS_CORE_ONLY:
 208                                 copied = access_process_vm(child, addr, &tmp,
 209                                                            to_copy, 0);
 210                                 if (copied)
 211                                         break;
 212
 213                                 /* hrm, why didn't that work ... maybe no mapping */
 214                                 if (addr >= FIXED_CODE_START &&
 215                                     addr + to_copy <= FIXED_CODE_END) {
 216                                         copy_from_user_page(0, 0, 0, &tmp, paddr, to_copy);
 217                                         copied = to_copy;
 218                                 } else if (addr >= BOOT_ROM_START) {
 219                                         memcpy(&tmp, paddr, to_copy);
 220                                         copied = to_copy;
 221                                 }
 222
 223                                 break;
 224                         case BFIN_MEM_ACCESS_DMA:
 225                                 if (safe_dma_memcpy(&tmp, paddr, to_copy))
 226                                         copied = to_copy;
 227                                 break;
 228                         case BFIN_MEM_ACCESS_ITEST:
 229                                 if (isram_memcpy(&tmp, paddr, to_copy))
 230                                         copied = to_copy;
 231                                 break;
 232                         default:
 233                                 copied = 0;
 234                                 break;
 235                         }
 236
 237                         pr_debug("ptrace: copied size %d [0x%08lx]\n", copied, tmp);
 238                         if (copied == to_copy)
 239                                 ret = put_user(tmp, datap);
 240                         break;
 241                 }
 242
 243                 /* read the word at location addr in the USER area. */
 244         case PTRACE_PEEKUSR:
 245                 {
 246                         unsigned long tmp;
 247                         ret = -EIO;
 248                         tmp = 0;
 249                         if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
 250                                 printk(KERN_WARNING "ptrace error : PEEKUSR : temporarily returning "
 251                                                     "0 - %x sizeof(pt_regs) is %lx\n",
 252                                      (int)addr, sizeof(struct pt_regs));
 253                                 break;
 254                         }
 255                         if (addr == sizeof(struct pt_regs)) {
 256                                 /* PT_TEXT_ADDR */
 257                                 tmp = child->mm->start_code + TEXT_OFFSET;
 258                         } else if (addr == (sizeof(struct pt_regs) + 4)) {
 259                                 /* PT_TEXT_END_ADDR */
 260                                 tmp = child->mm->end_code;
 261                         } else if (addr == (sizeof(struct pt_regs) + 8)) {
 262                                 /* PT_DATA_ADDR */
 263                                 tmp = child->mm->start_data;
 264 #ifdef CONFIG_BINFMT_ELF_FDPIC
 265                         } else if (addr == (sizeof(struct pt_regs) + 12)) {
 266                                 goto case_PTRACE_GETFDPIC_EXEC;
 267                         } else if (addr == (sizeof(struct pt_regs) + 16)) {
 268                                 goto case_PTRACE_GETFDPIC_INTERP;
 269 #endif
 270                         } else {
 271                                 tmp = get_reg(child, addr);
 272                         }
 273                         ret = put_user(tmp, datap);
 274                         break;
 275                 }
 276
 277 #ifdef CONFIG_BINFMT_ELF_FDPIC
 278         case PTRACE_GETFDPIC: {
 279                 unsigned long tmp = 0;
 280
 281                 switch (addr) {
 282                 case_PTRACE_GETFDPIC_EXEC:
 283                 case PTRACE_GETFDPIC_EXEC:
 284                         tmp = child->mm->context.exec_fdpic_loadmap;
 285                         break;
 286                 case_PTRACE_GETFDPIC_INTERP:
 287                 case PTRACE_GETFDPIC_INTERP:
 288                         tmp = child->mm->context.interp_fdpic_loadmap;
 289                         break;
 290                 default:
 291                         break;
 292                 }
 293
 294                 ret = put_user(tmp, datap);
 295                 break;
 296         }
 297 #endif
 298
 299                 /* when I and D space are separate, this will have to be fixed. */
 300         case PTRACE_POKEDATA:
 301                 pr_debug("ptrace: PTRACE_PEEKDATA\n");
 302                 /* fall through */
 303         case PTRACE_POKETEXT:   /* write the word at location addr. */
 304                 {
 305                         int copied = 0, to_copy = sizeof(data);
 306
 307                         ret = -EIO;
 308                         pr_debug("ptrace: POKETEXT at addr 0x%08lx + %i bytes %lx\n",
 309                                  addr, to_copy, data);
 310                         if (is_user_addr_valid(child, addr, to_copy) < 0)
 311                                 break;
 312                         pr_debug("ptrace: user address is valid\n");
 313
 314                         switch (bfin_mem_access_type(addr, to_copy)) {
 315                         case BFIN_MEM_ACCESS_CORE:
 316                         case BFIN_MEM_ACCESS_CORE_ONLY:
 317                                 copied = access_process_vm(child, addr, &data,
 318                                                            to_copy, 0);
 319                                 if (copied)
 320                                         break;
 321
 322                                 /* hrm, why didn't that work ... maybe no mapping */
 323                                 if (addr >= FIXED_CODE_START &&
 324                                     addr + to_copy <= FIXED_CODE_END) {
 325                                         copy_to_user_page(0, 0, 0, paddr, &data, to_copy);
 326                                         copied = to_copy;
 327                                 } else if (addr >= BOOT_ROM_START) {
 328                                         memcpy(paddr, &data, to_copy);
 329                                         copied = to_copy;
 330                                 }
 331
 332                                 break;
 333                         case BFIN_MEM_ACCESS_DMA:
 334                                 if (safe_dma_memcpy(paddr, &data, to_copy))
 335                                         copied = to_copy;
 336                                 break;
 337                         case BFIN_MEM_ACCESS_ITEST:
 338                                 if (isram_memcpy(paddr, &data, to_copy))
 339                                         copied = to_copy;
 340                                 break;
 341                         default:
 342                                 copied = 0;
 343                                 break;
 344                         }
 345
 346                         pr_debug("ptrace: copied size %d\n", copied);
 347                         if (copied == to_copy)
 348                                 ret = 0;
 349                         break;
 350                 }
 351
 352         case PTRACE_POKEUSR:    /* write the word at location addr in the USER area */
 353                 ret = -EIO;
 354                 if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
 355                         printk(KERN_WARNING "ptrace error : POKEUSR: temporarily returning 0\n");
 356                         break;
 357                 }
 358
 359                 if (addr >= (sizeof(struct pt_regs))) {
 360                         ret = 0;
 361                         break;
 362                 }
 363                 if (addr == PT_SYSCFG) {
 364                         data &= SYSCFG_MASK;
 365                         data |= get_reg(child, PT_SYSCFG);
 366                 }
 367                 ret = put_reg(child, addr, data);
 368                 break;
 369
 370         case PTRACE_SYSCALL:    /* continue and stop at next (return from) syscall */
 371         case PTRACE_CONT:       /* restart after signal. */
 372                 pr_debug("ptrace: syscall/cont\n");
 373
 374                 ret = -EIO;
 375                 if (!valid_signal(data))
 376                         break;
 377                 if (request == PTRACE_SYSCALL)
 378                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 379                 else
 380                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 381                 child->exit_code = data;
 382                 ptrace_disable(child);
 383                 pr_debug("ptrace: before wake_up_process\n");
 384                 wake_up_process(child);
 385                 ret = 0;
 386                 break;
 387
 388         /*
 389          * make the child exit.  Best I can do is send it a sigkill.
 390          * perhaps it should be put in the status that it wants to
 391          * exit.
 392          */
 393         case PTRACE_KILL:
 394                 ret = 0;
 395                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 396                         break;
 397                 child->exit_code = SIGKILL;
 398                 ptrace_disable(child);
 399                 wake_up_process(child);
 400                 break;
 401
 402         case PTRACE_SINGLESTEP: /* set the trap flag. */
 403                 pr_debug("ptrace: single step\n");
 404                 ret = -EIO;
 405                 if (!valid_signal(data))
 406                         break;
 407                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 408                 ptrace_enable(child);
 409                 child->exit_code = data;
 410                 wake_up_process(child);
 411                 ret = 0;
 412                 break;
 413
 414         case PTRACE_GETREGS:
 415                 /* Get all gp regs from the child. */
 416                 ret = ptrace_getregs(child, datap);
 417                 break;
 418
 419         case PTRACE_SETREGS:
 420                 printk(KERN_WARNING "ptrace: SETREGS: **** NOT IMPLEMENTED ***\n");
 421                 /* Set all gp regs in the child. */
 422                 ret = 0;
 423                 break;
 424
 425         default:
 426                 ret = ptrace_request(child, request, addr, data);
 427                 break;
 428         }
 429
 430         return ret;
 431 }
 432
 433 asmlinkage void syscall_trace(void)
 434 {
 435         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 436                 return;
 437
 438         if (!(current->ptrace & PT_PTRACED))
 439                 return;
 440
 441         /* the 0x80 provides a way for the tracing parent to distinguish
 442          * between a syscall stop and SIGTRAP delivery
 443          */
 444         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 445                                  ? 0x80 : 0));
 446
 447         /*
 448          * this isn't the same as continuing with a signal, but it will do
 449          * for normal use.  strace only continues with a signal if the
 450          * stopping signal is not SIGTRAP.  -brl
 451          */
 452         if (current->exit_code) {
 453                 send_sig(current->exit_code, current, 1);
 454                 current->exit_code = 0;
 455         }
 456 }