arch/blackfin/kernel/ptrace.c

   1 /*
   2  * File:         arch/blackfin/kernel/ptrace.c
   3  * Based on:     Taken from linux/kernel/ptrace.c
   4  * Author:       linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
   5  *
   6  * Created:      1/23/92
   7  * Description:
   8  *
   9  * Modified:
  10  *               Copyright 2004-2006 Analog Devices Inc.
  11  *
  12  * Bugs:         Enter bugs at http://blackfin.uclinux.org/
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, see the file COPYING, or write
  26  * to the Free Software Foundation, Inc.,
  27  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  28  */
  29
  30 #include <linux/kernel.h>
  31 #include <linux/sched.h>
  32 #include <linux/mm.h>
  33 #include <linux/smp.h>
  34 #include <linux/errno.h>
  35 #include <linux/ptrace.h>
  36 #include <linux/user.h>
  37 #include <linux/signal.h>
  38 #include <linux/uaccess.h>
  39
  40 #include <asm/page.h>
  41 #include <asm/pgtable.h>
  42 #include <asm/system.h>
  43 #include <asm/processor.h>
  44 #include <asm/asm-offsets.h>
  45 #include <asm/dma.h>
  46 #include <asm/fixed_code.h>
  47 #include <asm/cacheflush.h>
  48 #include <asm/mem_map.h>
  49
  50 #define TEXT_OFFSET 0
  51 /*
  52  * does not yet catch signals sent when the child dies.
  53  * in exit.c or in signal.c.
  54  */
  55
  56 /* determines which bits in the SYSCFG reg the user has access to. */
  57 /* 1 = access 0 = no access */
  58 #define SYSCFG_MASK 0x0007      /* SYSCFG reg */
  59 /* sets the trace bits. */
  60 #define TRACE_BITS 0x0001
  61
  62 /* Find the stack offset for a register, relative to thread.esp0. */
  63 #define PT_REG(reg)     ((long)&((struct pt_regs *)0)->reg)
  64
  65 /*
  66  * Get the address of the live pt_regs for the specified task.
  67  * These are saved onto the top kernel stack when the process
  68  * is not running.
  69  *
  70  * Note: if a user thread is execve'd from kernel space, the
  71  * kernel stack will not be empty on entry to the kernel, so
  72  * ptracing these tasks will fail.
  73  */
  74 static inline struct pt_regs *get_user_regs(struct task_struct *task)
  75 {
  76         return (struct pt_regs *)
  77             ((unsigned long)task_stack_page(task) +
  78              (THREAD_SIZE - sizeof(struct pt_regs)));
  79 }
  80
  81 /*
  82  * Get all user integer registers.
  83  */
  84 static inline int ptrace_getregs(struct task_struct *tsk, void __user *uregs)
  85 {
  86         struct pt_regs regs;
  87         memcpy(&regs, get_user_regs(tsk), sizeof(regs));
  88         regs.usp = tsk->thread.usp;
  89         return copy_to_user(uregs, &regs, sizeof(struct pt_regs)) ? -EFAULT : 0;
  90 }
  91
  92 /* Mapping from PT_xxx to the stack offset at which the register is
  93  * saved.  Notice that usp has no stack-slot and needs to be treated
  94  * specially (see get_reg/put_reg below).
  95  */
  96
  97 /*
  98  * Get contents of register REGNO in task TASK.
  99  */
 100 static inline long get_reg(struct task_struct *task, int regno)
 101 {
 102         unsigned char *reg_ptr;
 103
 104         struct pt_regs *regs =
 105             (struct pt_regs *)((unsigned long)task_stack_page(task) +
 106                                (THREAD_SIZE - sizeof(struct pt_regs)));
 107         reg_ptr = (char *)regs;
 108
 109         switch (regno) {
 110         case PT_USP:
 111                 return task->thread.usp;
 112         default:
 113                 if (regno <= 216)
 114                         return *(long *)(reg_ptr + regno);
 115         }
 116         /* slight mystery ... never seems to come here but kernel misbehaves without this code! */
 117
 118         printk(KERN_WARNING "Request to get for unknown register %d\n", regno);
 119         return 0;
 120 }
 121
 122 /*
 123  * Write contents of register REGNO in task TASK.
 124  */
 125 static inline int
 126 put_reg(struct task_struct *task, int regno, unsigned long data)
 127 {
 128         char *reg_ptr;
 129
 130         struct pt_regs *regs =
 131             (struct pt_regs *)((unsigned long)task_stack_page(task) +
 132                                (THREAD_SIZE - sizeof(struct pt_regs)));
 133         reg_ptr = (char *)regs;
 134
 135         switch (regno) {
 136         case PT_PC:
 137                 /*********************************************************************/
 138                 /* At this point the kernel is most likely in exception.             */
 139                 /* The RETX register will be used to populate the pc of the process. */
 140                 /*********************************************************************/
 141                 regs->retx = data;
 142                 regs->pc = data;
 143                 break;
 144         case PT_RETX:
 145                 break;          /* regs->retx = data; break; */
 146         case PT_USP:
 147                 regs->usp = data;
 148                 task->thread.usp = data;
 149                 break;
 150         default:
 151                 if (regno <= 216)
 152                         *(long *)(reg_ptr + regno) = data;
 153         }
 154         return 0;
 155 }
 156
 157 /*
 158  * check that an address falls within the bounds of the target process's memory mappings
 159  */
 160 static inline int is_user_addr_valid(struct task_struct *child,
 161                                      unsigned long start, unsigned long len)
 162 {
 163         struct vm_area_struct *vma;
 164         struct sram_list_struct *sraml;
 165
 166         /* overflow */
 167         if (start + len < start)
 168                 return -EIO;
 169
 170         vma = find_vma(child->mm, start);
 171         if (vma && start >= vma->vm_start && start + len <= vma->vm_end)
 172                         return 0;
 173
 174         for (sraml = child->mm->context.sram_list; sraml; sraml = sraml->next)
 175                 if (start >= (unsigned long)sraml->addr
 176                     && start + len < (unsigned long)sraml->addr + sraml->length)
 177                         return 0;
 178
 179         if (start >= FIXED_CODE_START && start + len < FIXED_CODE_END)
 180                 return 0;
 181
 182         return -EIO;
 183 }
 184
 185 void ptrace_enable(struct task_struct *child)
 186 {
 187         unsigned long tmp;
 188         tmp = get_reg(child, PT_SYSCFG) | (TRACE_BITS);
 189         put_reg(child, PT_SYSCFG, tmp);
 190 }
 191
 192 /*
 193  * Called by kernel/ptrace.c when detaching..
 194  *
 195  * Make sure the single step bit is not set.
 196  */
 197 void ptrace_disable(struct task_struct *child)
 198 {
 199         unsigned long tmp;
 200         /* make sure the single step bit is not set. */
 201         tmp = get_reg(child, PT_SYSCFG) & ~TRACE_BITS;
 202         put_reg(child, PT_SYSCFG, tmp);
 203 }
 204
 205 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 206 {
 207         int ret;
 208         unsigned long __user *datap = (unsigned long __user *)data;
 209         void *paddr = (void *)addr;
 210
 211         switch (request) {
 212                 /* when I and D space are separate, these will need to be fixed. */
 213         case PTRACE_PEEKDATA:
 214                 pr_debug("ptrace: PEEKDATA\n");
 215                 /* fall through */
 216         case PTRACE_PEEKTEXT:   /* read word at location addr. */
 217                 {
 218                         unsigned long tmp = 0;
 219                         int copied = 0, to_copy = sizeof(tmp);
 220
 221                         ret = -EIO;
 222                         pr_debug("ptrace: PEEKTEXT at addr 0x%08lx + %i\n", addr, to_copy);
 223                         if (is_user_addr_valid(child, addr, to_copy) < 0)
 224                                 break;
 225                         pr_debug("ptrace: user address is valid\n");
 226
 227                         switch (bfin_mem_access_type(addr, to_copy)) {
 228                         case BFIN_MEM_ACCESS_CORE:
 229                         case BFIN_MEM_ACCESS_CORE_ONLY:
 230                                 copied = access_process_vm(child, addr, &tmp,
 231                                                            to_copy, 0);
 232                                 if (copied)
 233                                         break;
 234
 235                                 /* hrm, why didn't that work ... maybe no mapping */
 236                                 if (addr >= FIXED_CODE_START &&
 237                                     addr + to_copy <= FIXED_CODE_END) {
 238                                         copy_from_user_page(0, 0, 0, &tmp, paddr, to_copy);
 239                                         copied = to_copy;
 240                                 } else if (addr >= BOOT_ROM_START) {
 241                                         memcpy(&tmp, paddr, to_copy);
 242                                         copied = to_copy;
 243                                 }
 244
 245                                 break;
 246                         case BFIN_MEM_ACCESS_DMA:
 247                                 if (safe_dma_memcpy(&tmp, paddr, to_copy))
 248                                         copied = to_copy;
 249                                 break;
 250                         case BFIN_MEM_ACCESS_ITEST:
 251                                 if (isram_memcpy(&tmp, paddr, to_copy))
 252                                         copied = to_copy;
 253                                 break;
 254                         default:
 255                                 copied = 0;
 256                                 break;
 257                         }
 258
 259                         pr_debug("ptrace: copied size %d [0x%08lx]\n", copied, tmp);
 260                         if (copied == to_copy)
 261                                 ret = put_user(tmp, datap);
 262                         break;
 263                 }
 264
 265                 /* read the word at location addr in the USER area. */
 266         case PTRACE_PEEKUSR:
 267                 {
 268                         unsigned long tmp;
 269                         ret = -EIO;
 270                         tmp = 0;
 271                         if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
 272                                 printk(KERN_WARNING "ptrace error : PEEKUSR : temporarily returning "
 273                                                     "0 - %x sizeof(pt_regs) is %lx\n",
 274                                      (int)addr, sizeof(struct pt_regs));
 275                                 break;
 276                         }
 277                         if (addr == sizeof(struct pt_regs)) {
 278                                 /* PT_TEXT_ADDR */
 279                                 tmp = child->mm->start_code + TEXT_OFFSET;
 280                         } else if (addr == (sizeof(struct pt_regs) + 4)) {
 281                                 /* PT_TEXT_END_ADDR */
 282                                 tmp = child->mm->end_code;
 283                         } else if (addr == (sizeof(struct pt_regs) + 8)) {
 284                                 /* PT_DATA_ADDR */
 285                                 tmp = child->mm->start_data;
 286 #ifdef CONFIG_BINFMT_ELF_FDPIC
 287                         } else if (addr == (sizeof(struct pt_regs) + 12)) {
 288                                 goto case_PTRACE_GETFDPIC_EXEC;
 289                         } else if (addr == (sizeof(struct pt_regs) + 16)) {
 290                                 goto case_PTRACE_GETFDPIC_INTERP;
 291 #endif
 292                         } else {
 293                                 tmp = get_reg(child, addr);
 294                         }
 295                         ret = put_user(tmp, datap);
 296                         break;
 297                 }
 298
 299 #ifdef CONFIG_BINFMT_ELF_FDPIC
 300         case PTRACE_GETFDPIC: {
 301                 unsigned long tmp = 0;
 302
 303                 switch (addr) {
 304                 case_PTRACE_GETFDPIC_EXEC:
 305                 case PTRACE_GETFDPIC_EXEC:
 306                         tmp = child->mm->context.exec_fdpic_loadmap;
 307                         break;
 308                 case_PTRACE_GETFDPIC_INTERP:
 309                 case PTRACE_GETFDPIC_INTERP:
 310                         tmp = child->mm->context.interp_fdpic_loadmap;
 311                         break;
 312                 default:
 313                         break;
 314                 }
 315
 316                 ret = put_user(tmp, datap);
 317                 break;
 318         }
 319 #endif
 320
 321                 /* when I and D space are separate, this will have to be fixed. */
 322         case PTRACE_POKEDATA:
 323                 pr_debug("ptrace: PTRACE_PEEKDATA\n");
 324                 /* fall through */
 325         case PTRACE_POKETEXT:   /* write the word at location addr. */
 326                 {
 327                         int copied = 0, to_copy = sizeof(data);
 328
 329                         ret = -EIO;
 330                         pr_debug("ptrace: POKETEXT at addr 0x%08lx + %i bytes %lx\n",
 331                                  addr, to_copy, data);
 332                         if (is_user_addr_valid(child, addr, to_copy) < 0)
 333                                 break;
 334                         pr_debug("ptrace: user address is valid\n");
 335
 336                         switch (bfin_mem_access_type(addr, to_copy)) {
 337                         case BFIN_MEM_ACCESS_CORE:
 338                         case BFIN_MEM_ACCESS_CORE_ONLY:
 339                                 copied = access_process_vm(child, addr, &data,
 340                                                            to_copy, 0);
 341                                 if (copied)
 342                                         break;
 343
 344                                 /* hrm, why didn't that work ... maybe no mapping */
 345                                 if (addr >= FIXED_CODE_START &&
 346                                     addr + to_copy <= FIXED_CODE_END) {
 347                                         copy_to_user_page(0, 0, 0, paddr, &data, to_copy);
 348                                         copied = to_copy;
 349                                 } else if (addr >= BOOT_ROM_START) {
 350                                         memcpy(paddr, &data, to_copy);
 351                                         copied = to_copy;
 352                                 }
 353
 354                                 break;
 355                         case BFIN_MEM_ACCESS_DMA:
 356                                 if (safe_dma_memcpy(paddr, &data, to_copy))
 357                                         copied = to_copy;
 358                                 break;
 359                         case BFIN_MEM_ACCESS_ITEST:
 360                                 if (isram_memcpy(paddr, &data, to_copy))
 361                                         copied = to_copy;
 362                                 break;
 363                         default:
 364                                 copied = 0;
 365                                 break;
 366                         }
 367
 368                         pr_debug("ptrace: copied size %d\n", copied);
 369                         if (copied == to_copy)
 370                                 ret = 0;
 371                         break;
 372                 }
 373
 374         case PTRACE_POKEUSR:    /* write the word at location addr in the USER area */
 375                 ret = -EIO;
 376                 if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
 377                         printk(KERN_WARNING "ptrace error : POKEUSR: temporarily returning 0\n");
 378                         break;
 379                 }
 380
 381                 if (addr >= (sizeof(struct pt_regs))) {
 382                         ret = 0;
 383                         break;
 384                 }
 385                 if (addr == PT_SYSCFG) {
 386                         data &= SYSCFG_MASK;
 387                         data |= get_reg(child, PT_SYSCFG);
 388                 }
 389                 ret = put_reg(child, addr, data);
 390                 break;
 391
 392         case PTRACE_SYSCALL:    /* continue and stop at next (return from) syscall */
 393         case PTRACE_CONT:       /* restart after signal. */
 394                 pr_debug("ptrace: syscall/cont\n");
 395
 396                 ret = -EIO;
 397                 if (!valid_signal(data))
 398                         break;
 399                 if (request == PTRACE_SYSCALL)
 400                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 401                 else
 402                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 403                 child->exit_code = data;
 404                 ptrace_disable(child);
 405                 pr_debug("ptrace: before wake_up_process\n");
 406                 wake_up_process(child);
 407                 ret = 0;
 408                 break;
 409
 410         /*
 411          * make the child exit.  Best I can do is send it a sigkill.
 412          * perhaps it should be put in the status that it wants to
 413          * exit.
 414          */
 415         case PTRACE_KILL:
 416                 ret = 0;
 417                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 418                         break;
 419                 child->exit_code = SIGKILL;
 420                 ptrace_disable(child);
 421                 wake_up_process(child);
 422                 break;
 423
 424         case PTRACE_SINGLESTEP: /* set the trap flag. */
 425                 pr_debug("ptrace: single step\n");
 426                 ret = -EIO;
 427                 if (!valid_signal(data))
 428                         break;
 429                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 430                 ptrace_enable(child);
 431                 child->exit_code = data;
 432                 wake_up_process(child);
 433                 ret = 0;
 434                 break;
 435
 436         case PTRACE_GETREGS:
 437                 /* Get all gp regs from the child. */
 438                 ret = ptrace_getregs(child, datap);
 439                 break;
 440
 441         case PTRACE_SETREGS:
 442                 printk(KERN_WARNING "ptrace: SETREGS: **** NOT IMPLEMENTED ***\n");
 443                 /* Set all gp regs in the child. */
 444                 ret = 0;
 445                 break;
 446
 447         default:
 448                 ret = ptrace_request(child, request, addr, data);
 449                 break;
 450         }
 451
 452         return ret;
 453 }
 454
 455 asmlinkage void syscall_trace(void)
 456 {
 457         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 458                 return;
 459
 460         if (!(current->ptrace & PT_PTRACED))
 461                 return;
 462
 463         /* the 0x80 provides a way for the tracing parent to distinguish
 464          * between a syscall stop and SIGTRAP delivery
 465          */
 466         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 467                                  ? 0x80 : 0));
 468
 469         /*
 470          * this isn't the same as continuing with a signal, but it will do
 471          * for normal use.  strace only continues with a signal if the
 472          * stopping signal is not SIGTRAP.  -brl
 473          */
 474         if (current->exit_code) {
 475                 send_sig(current->exit_code, current, 1);
 476                 current->exit_code = 0;
 477         }
 478 }