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/smp_lock.h>
  35 #include <linux/errno.h>
  36 #include <linux/ptrace.h>
  37 #include <linux/user.h>
  38 #include <linux/signal.h>
  39 #include <linux/uaccess.h>
  40
  41 #include <asm/page.h>
  42 #include <asm/pgtable.h>
  43 #include <asm/system.h>
  44 #include <asm/processor.h>
  45 #include <asm/asm-offsets.h>
  46 #include <asm/dma.h>
  47 #include <asm/fixed_code.h>
  48 #include <asm/cacheflush.h>
  49 #include <asm/mem_map.h>
  50
  51 #define TEXT_OFFSET 0
  52 /*
  53  * does not yet catch signals sent when the child dies.
  54  * in exit.c or in signal.c.
  55  */
  56
  57 /* determines which bits in the SYSCFG reg the user has access to. */
  58 /* 1 = access 0 = no access */
  59 #define SYSCFG_MASK 0x0007      /* SYSCFG reg */
  60 /* sets the trace bits. */
  61 #define TRACE_BITS 0x0001
  62
  63 /* Find the stack offset for a register, relative to thread.esp0. */
  64 #define PT_REG(reg)     ((long)&((struct pt_regs *)0)->reg)
  65
  66 /*
  67  * Get the address of the live pt_regs for the specified task.
  68  * These are saved onto the top kernel stack when the process
  69  * is not running.
  70  *
  71  * Note: if a user thread is execve'd from kernel space, the
  72  * kernel stack will not be empty on entry to the kernel, so
  73  * ptracing these tasks will fail.
  74  */
  75 static inline struct pt_regs *get_user_regs(struct task_struct *task)
  76 {
  77         return (struct pt_regs *)
  78             ((unsigned long)task_stack_page(task) +
  79              (THREAD_SIZE - sizeof(struct pt_regs)));
  80 }
  81
  82 /*
  83  * Get all user integer registers.
  84  */
  85 static inline int ptrace_getregs(struct task_struct *tsk, void __user *uregs)
  86 {
  87         struct pt_regs regs;
  88         memcpy(&regs, get_user_regs(tsk), sizeof(regs));
  89         regs.usp = tsk->thread.usp;
  90         return copy_to_user(uregs, &regs, sizeof(struct pt_regs)) ? -EFAULT : 0;
  91 }
  92
  93 /* Mapping from PT_xxx to the stack offset at which the register is
  94  * saved.  Notice that usp has no stack-slot and needs to be treated
  95  * specially (see get_reg/put_reg below).
  96  */
  97
  98 /*
  99  * Get contents of register REGNO in task TASK.
 100  */
 101 static inline long get_reg(struct task_struct *task, int regno)
 102 {
 103         unsigned char *reg_ptr;
 104
 105         struct pt_regs *regs =
 106             (struct pt_regs *)((unsigned long)task_stack_page(task) +
 107                                (THREAD_SIZE - sizeof(struct pt_regs)));
 108         reg_ptr = (char *)regs;
 109
 110         switch (regno) {
 111         case PT_USP:
 112                 return task->thread.usp;
 113         default:
 114                 if (regno <= 216)
 115                         return *(long *)(reg_ptr + regno);
 116         }
 117         /* slight mystery ... never seems to come here but kernel misbehaves without this code! */
 118
 119         printk(KERN_WARNING "Request to get for unknown register %d\n", regno);
 120         return 0;
 121 }
 122
 123 /*
 124  * Write contents of register REGNO in task TASK.
 125  */
 126 static inline int
 127 put_reg(struct task_struct *task, int regno, unsigned long data)
 128 {
 129         char *reg_ptr;
 130
 131         struct pt_regs *regs =
 132             (struct pt_regs *)((unsigned long)task_stack_page(task) +
 133                                (THREAD_SIZE - sizeof(struct pt_regs)));
 134         reg_ptr = (char *)regs;
 135
 136         switch (regno) {
 137         case PT_PC:
 138                 /*********************************************************************/
 139                 /* At this point the kernel is most likely in exception.             */
 140                 /* The RETX register will be used to populate the pc of the process. */
 141                 /*********************************************************************/
 142                 regs->retx = data;
 143                 regs->pc = data;
 144                 break;
 145         case PT_RETX:
 146                 break;          /* regs->retx = data; break; */
 147         case PT_USP:
 148                 regs->usp = data;
 149                 task->thread.usp = data;
 150                 break;
 151         default:
 152                 if (regno <= 216)
 153                         *(long *)(reg_ptr + regno) = data;
 154         }
 155         return 0;
 156 }
 157
 158 /*
 159  * check that an address falls within the bounds of the target process's memory mappings
 160  */
 161 static inline int is_user_addr_valid(struct task_struct *child,
 162                                      unsigned long start, unsigned long len)
 163 {
 164         struct vm_area_struct *vma;
 165         struct sram_list_struct *sraml;
 166
 167         /* overflow */
 168         if (start + len < start)
 169                 return -EIO;
 170
 171         vma = find_vma(child->mm, start);
 172         if (vma && start >= vma->vm_start && start + len <= vma->vm_end)
 173                         return 0;
 174
 175         for (sraml = child->mm->context.sram_list; sraml; sraml = sraml->next)
 176                 if (start >= (unsigned long)sraml->addr
 177                     && start + len < (unsigned long)sraml->addr + sraml->length)
 178                         return 0;
 179
 180         if (start >= FIXED_CODE_START && start + len < FIXED_CODE_END)
 181                 return 0;
 182
 183         return -EIO;
 184 }
 185
 186 void ptrace_enable(struct task_struct *child)
 187 {
 188         unsigned long tmp;
 189         tmp = get_reg(child, PT_SYSCFG) | (TRACE_BITS);
 190         put_reg(child, PT_SYSCFG, tmp);
 191 }
 192
 193 /*
 194  * Called by kernel/ptrace.c when detaching..
 195  *
 196  * Make sure the single step bit is not set.
 197  */
 198 void ptrace_disable(struct task_struct *child)
 199 {
 200         unsigned long tmp;
 201         /* make sure the single step bit is not set. */
 202         tmp = get_reg(child, PT_SYSCFG) & ~TRACE_BITS;
 203         put_reg(child, PT_SYSCFG, tmp);
 204 }
 205
 206 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 207 {
 208         int ret;
 209         unsigned long __user *datap = (unsigned long __user *)data;
 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;
 220
 221                         ret = -EIO;
 222                         pr_debug("ptrace: PEEKTEXT at addr 0x%08lx + %ld\n", addr, sizeof(data));
 223                         if (is_user_addr_valid(child, addr, sizeof(tmp)) < 0)
 224                                 break;
 225                         pr_debug("ptrace: user address is valid\n");
 226
 227                         if (L1_CODE_LENGTH != 0 && addr >= get_l1_code_start()
 228                             && addr + sizeof(tmp) <= get_l1_code_start() + L1_CODE_LENGTH) {
 229                                 safe_dma_memcpy (&tmp, (const void *)(addr), sizeof(tmp));
 230                                 copied = sizeof(tmp);
 231
 232                         } else if (L1_DATA_A_LENGTH != 0 && addr >= L1_DATA_A_START
 233                             && addr + sizeof(tmp) <= L1_DATA_A_START + L1_DATA_A_LENGTH) {
 234                                 memcpy(&tmp, (const void *)(addr), sizeof(tmp));
 235                                 copied = sizeof(tmp);
 236
 237                         } else if (L1_DATA_B_LENGTH != 0 && addr >= L1_DATA_B_START
 238                             && addr + sizeof(tmp) <= L1_DATA_B_START + L1_DATA_B_LENGTH) {
 239                                 memcpy(&tmp, (const void *)(addr), sizeof(tmp));
 240                                 copied = sizeof(tmp);
 241
 242                         } else if (addr >= FIXED_CODE_START
 243                             && addr + sizeof(tmp) <= FIXED_CODE_END) {
 244                                 copy_from_user_page(0, 0, 0, &tmp, (const void *)(addr), sizeof(tmp));
 245                                 copied = sizeof(tmp);
 246
 247                         } else
 248                                 copied = access_process_vm(child, addr, &tmp,
 249                                                            sizeof(tmp), 0);
 250
 251                         pr_debug("ptrace: copied size %d [0x%08lx]\n", copied, tmp);
 252                         if (copied != sizeof(tmp))
 253                                 break;
 254                         ret = put_user(tmp, datap);
 255                         break;
 256                 }
 257
 258                 /* read the word at location addr in the USER area. */
 259         case PTRACE_PEEKUSR:
 260                 {
 261                         unsigned long tmp;
 262                         ret = -EIO;
 263                         tmp = 0;
 264                         if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
 265                                 printk(KERN_WARNING "ptrace error : PEEKUSR : temporarily returning "
 266                                                     "0 - %x sizeof(pt_regs) is %lx\n",
 267                                      (int)addr, sizeof(struct pt_regs));
 268                                 break;
 269                         }
 270                         if (addr == sizeof(struct pt_regs)) {
 271                                 /* PT_TEXT_ADDR */
 272                                 tmp = child->mm->start_code + TEXT_OFFSET;
 273                         } else if (addr == (sizeof(struct pt_regs) + 4)) {
 274                                 /* PT_TEXT_END_ADDR */
 275                                 tmp = child->mm->end_code;
 276                         } else if (addr == (sizeof(struct pt_regs) + 8)) {
 277                                 /* PT_DATA_ADDR */
 278                                 tmp = child->mm->start_data;
 279 #ifdef CONFIG_BINFMT_ELF_FDPIC
 280                         } else if (addr == (sizeof(struct pt_regs) + 12)) {
 281                                 tmp = child->mm->context.exec_fdpic_loadmap;
 282                         } else if (addr == (sizeof(struct pt_regs) + 16)) {
 283                                 tmp = child->mm->context.interp_fdpic_loadmap;
 284 #endif
 285                         } else {
 286                                 tmp = get_reg(child, addr);
 287                         }
 288                         ret = put_user(tmp, datap);
 289                         break;
 290                 }
 291
 292                 /* when I and D space are separate, this will have to be fixed. */
 293         case PTRACE_POKEDATA:
 294                 pr_debug("ptrace: PTRACE_PEEKDATA\n");
 295                 /* fall through */
 296         case PTRACE_POKETEXT:   /* write the word at location addr. */
 297                 {
 298                         int copied;
 299
 300                         ret = -EIO;
 301                         pr_debug("ptrace: POKETEXT at addr 0x%08lx + %ld bytes %lx\n",
 302                                  addr, sizeof(data), data);
 303                         if (is_user_addr_valid(child, addr, sizeof(data)) < 0)
 304                                 break;
 305                         pr_debug("ptrace: user address is valid\n");
 306
 307                         if (L1_CODE_LENGTH != 0 && addr >= get_l1_code_start()
 308                             && addr + sizeof(data) <= get_l1_code_start() + L1_CODE_LENGTH) {
 309                                 safe_dma_memcpy ((void *)(addr), &data, sizeof(data));
 310                                 copied = sizeof(data);
 311
 312                         } else if (L1_DATA_A_LENGTH != 0 && addr >= L1_DATA_A_START
 313                             && addr + sizeof(data) <= L1_DATA_A_START + L1_DATA_A_LENGTH) {
 314                                 memcpy((void *)(addr), &data, sizeof(data));
 315                                 copied = sizeof(data);
 316
 317                         } else if (L1_DATA_B_LENGTH != 0 && addr >= L1_DATA_B_START
 318                             && addr + sizeof(data) <= L1_DATA_B_START + L1_DATA_B_LENGTH) {
 319                                 memcpy((void *)(addr), &data, sizeof(data));
 320                                 copied = sizeof(data);
 321
 322                         } else if (addr >= FIXED_CODE_START
 323                             && addr + sizeof(data) <= FIXED_CODE_END) {
 324                                 copy_to_user_page(0, 0, 0, (void *)(addr), &data, sizeof(data));
 325                                 copied = sizeof(data);
 326
 327                         } else
 328                                 copied = access_process_vm(child, addr, &data,
 329                                                            sizeof(data), 1);
 330
 331                         pr_debug("ptrace: copied size %d\n", copied);
 332                         if (copied != sizeof(data))
 333                                 break;
 334                         ret = 0;
 335                         break;
 336                 }
 337
 338         case PTRACE_POKEUSR:    /* write the word at location addr in the USER area */
 339                 ret = -EIO;
 340                 if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
 341                         printk(KERN_WARNING "ptrace error : POKEUSR: temporarily returning 0\n");
 342                         break;
 343                 }
 344
 345                 if (addr >= (sizeof(struct pt_regs))) {
 346                         ret = 0;
 347                         break;
 348                 }
 349                 if (addr == PT_SYSCFG) {
 350                         data &= SYSCFG_MASK;
 351                         data |= get_reg(child, PT_SYSCFG);
 352                 }
 353                 ret = put_reg(child, addr, data);
 354                 break;
 355
 356         case PTRACE_SYSCALL:    /* continue and stop at next (return from) syscall */
 357         case PTRACE_CONT:       /* restart after signal. */
 358                 pr_debug("ptrace: syscall/cont\n");
 359
 360                 ret = -EIO;
 361                 if (!valid_signal(data))
 362                         break;
 363                 if (request == PTRACE_SYSCALL)
 364                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 365                 else
 366                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 367                 child->exit_code = data;
 368                 ptrace_disable(child);
 369                 pr_debug("ptrace: before wake_up_process\n");
 370                 wake_up_process(child);
 371                 ret = 0;
 372                 break;
 373
 374         /*
 375          * make the child exit.  Best I can do is send it a sigkill.
 376          * perhaps it should be put in the status that it wants to
 377          * exit.
 378          */
 379         case PTRACE_KILL:
 380                 ret = 0;
 381                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 382                         break;
 383                 child->exit_code = SIGKILL;
 384                 ptrace_disable(child);
 385                 wake_up_process(child);
 386                 break;
 387
 388         case PTRACE_SINGLESTEP: /* set the trap flag. */
 389                 pr_debug("ptrace: single step\n");
 390                 ret = -EIO;
 391                 if (!valid_signal(data))
 392                         break;
 393                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 394                 ptrace_enable(child);
 395                 child->exit_code = data;
 396                 wake_up_process(child);
 397                 ret = 0;
 398                 break;
 399
 400         case PTRACE_GETREGS:
 401                 /* Get all gp regs from the child. */
 402                 ret = ptrace_getregs(child, datap);
 403                 break;
 404
 405         case PTRACE_SETREGS:
 406                 printk(KERN_WARNING "ptrace: SETREGS: **** NOT IMPLEMENTED ***\n");
 407                 /* Set all gp regs in the child. */
 408                 ret = 0;
 409                 break;
 410
 411         default:
 412                 ret = ptrace_request(child, request, addr, data);
 413                 break;
 414         }
 415
 416         return ret;
 417 }
 418
 419 asmlinkage void syscall_trace(void)
 420 {
 421         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 422                 return;
 423
 424         if (!(current->ptrace & PT_PTRACED))
 425                 return;
 426
 427         /* the 0x80 provides a way for the tracing parent to distinguish
 428          * between a syscall stop and SIGTRAP delivery
 429          */
 430         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 431                                  ? 0x80 : 0));
 432
 433         /*
 434          * this isn't the same as continuing with a signal, but it will do
 435          * for normal use.  strace only continues with a signal if the
 436          * stopping signal is not SIGTRAP.  -brl
 437          */
 438         if (current->exit_code) {
 439                 send_sig(current->exit_code, current, 1);
 440                 current->exit_code = 0;
 441         }
 442 }