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
 210         switch (request) {
 211                 /* when I and D space are separate, these will need to be fixed. */
 212         case PTRACE_PEEKDATA:
 213                 pr_debug("ptrace: PEEKDATA\n");
 214                 /* fall through */
 215         case PTRACE_PEEKTEXT:   /* read word at location addr. */
 216                 {
 217                         unsigned long tmp = 0;
 218                         int copied;
 219
 220                         ret = -EIO;
 221                         pr_debug("ptrace: PEEKTEXT at addr 0x%08lx + %ld\n", addr, sizeof(data));
 222                         if (is_user_addr_valid(child, addr, sizeof(tmp)) < 0)
 223                                 break;
 224                         pr_debug("ptrace: user address is valid\n");
 225
 226                         if (L1_CODE_LENGTH != 0 && addr >= get_l1_code_start()
 227                             && addr + sizeof(tmp) <= get_l1_code_start() + L1_CODE_LENGTH) {
 228                                 safe_dma_memcpy (&tmp, (const void *)(addr), sizeof(tmp));
 229                                 copied = sizeof(tmp);
 230
 231                         } else if (L1_DATA_A_LENGTH != 0 && addr >= L1_DATA_A_START
 232                             && addr + sizeof(tmp) <= L1_DATA_A_START + L1_DATA_A_LENGTH) {
 233                                 memcpy(&tmp, (const void *)(addr), sizeof(tmp));
 234                                 copied = sizeof(tmp);
 235
 236                         } else if (L1_DATA_B_LENGTH != 0 && addr >= L1_DATA_B_START
 237                             && addr + sizeof(tmp) <= L1_DATA_B_START + L1_DATA_B_LENGTH) {
 238                                 memcpy(&tmp, (const void *)(addr), sizeof(tmp));
 239                                 copied = sizeof(tmp);
 240
 241                         } else if (addr >= FIXED_CODE_START
 242                             && addr + sizeof(tmp) <= FIXED_CODE_END) {
 243                                 copy_from_user_page(0, 0, 0, &tmp, (const void *)(addr), sizeof(tmp));
 244                                 copied = sizeof(tmp);
 245
 246                         } else
 247                                 copied = access_process_vm(child, addr, &tmp,
 248                                                            sizeof(tmp), 0);
 249
 250                         pr_debug("ptrace: copied size %d [0x%08lx]\n", copied, tmp);
 251                         if (copied != sizeof(tmp))
 252                                 break;
 253                         ret = put_user(tmp, datap);
 254                         break;
 255                 }
 256
 257                 /* read the word at location addr in the USER area. */
 258         case PTRACE_PEEKUSR:
 259                 {
 260                         unsigned long tmp;
 261                         ret = -EIO;
 262                         tmp = 0;
 263                         if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
 264                                 printk(KERN_WARNING "ptrace error : PEEKUSR : temporarily returning "
 265                                                     "0 - %x sizeof(pt_regs) is %lx\n",
 266                                      (int)addr, sizeof(struct pt_regs));
 267                                 break;
 268                         }
 269                         if (addr == sizeof(struct pt_regs)) {
 270                                 /* PT_TEXT_ADDR */
 271                                 tmp = child->mm->start_code + TEXT_OFFSET;
 272                         } else if (addr == (sizeof(struct pt_regs) + 4)) {
 273                                 /* PT_TEXT_END_ADDR */
 274                                 tmp = child->mm->end_code;
 275                         } else if (addr == (sizeof(struct pt_regs) + 8)) {
 276                                 /* PT_DATA_ADDR */
 277                                 tmp = child->mm->start_data;
 278 #ifdef CONFIG_BINFMT_ELF_FDPIC
 279                         } else if (addr == (sizeof(struct pt_regs) + 12)) {
 280                                 tmp = child->mm->context.exec_fdpic_loadmap;
 281                         } else if (addr == (sizeof(struct pt_regs) + 16)) {
 282                                 tmp = child->mm->context.interp_fdpic_loadmap;
 283 #endif
 284                         } else {
 285                                 tmp = get_reg(child, addr);
 286                         }
 287                         ret = put_user(tmp, datap);
 288                         break;
 289                 }
 290
 291                 /* when I and D space are separate, this will have to be fixed. */
 292         case PTRACE_POKEDATA:
 293                 pr_debug("ptrace: PTRACE_PEEKDATA\n");
 294                 /* fall through */
 295         case PTRACE_POKETEXT:   /* write the word at location addr. */
 296                 {
 297                         int copied;
 298
 299                         ret = -EIO;
 300                         pr_debug("ptrace: POKETEXT at addr 0x%08lx + %ld bytes %lx\n",
 301                                  addr, sizeof(data), data);
 302                         if (is_user_addr_valid(child, addr, sizeof(data)) < 0)
 303                                 break;
 304                         pr_debug("ptrace: user address is valid\n");
 305
 306                         if (L1_CODE_LENGTH != 0 && addr >= get_l1_code_start()
 307                             && addr + sizeof(data) <= get_l1_code_start() + L1_CODE_LENGTH) {
 308                                 safe_dma_memcpy ((void *)(addr), &data, sizeof(data));
 309                                 copied = sizeof(data);
 310
 311                         } else if (L1_DATA_A_LENGTH != 0 && addr >= L1_DATA_A_START
 312                             && addr + sizeof(data) <= L1_DATA_A_START + L1_DATA_A_LENGTH) {
 313                                 memcpy((void *)(addr), &data, sizeof(data));
 314                                 copied = sizeof(data);
 315
 316                         } else if (L1_DATA_B_LENGTH != 0 && addr >= L1_DATA_B_START
 317                             && addr + sizeof(data) <= L1_DATA_B_START + L1_DATA_B_LENGTH) {
 318                                 memcpy((void *)(addr), &data, sizeof(data));
 319                                 copied = sizeof(data);
 320
 321                         } else if (addr >= FIXED_CODE_START
 322                             && addr + sizeof(data) <= FIXED_CODE_END) {
 323                                 copy_to_user_page(0, 0, 0, (void *)(addr), &data, sizeof(data));
 324                                 copied = sizeof(data);
 325
 326                         } else
 327                                 copied = access_process_vm(child, addr, &data,
 328                                                            sizeof(data), 1);
 329
 330                         pr_debug("ptrace: copied size %d\n", copied);
 331                         if (copied != sizeof(data))
 332                                 break;
 333                         ret = 0;
 334                         break;
 335                 }
 336
 337         case PTRACE_POKEUSR:    /* write the word at location addr in the USER area */
 338                 ret = -EIO;
 339                 if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
 340                         printk(KERN_WARNING "ptrace error : POKEUSR: temporarily returning 0\n");
 341                         break;
 342                 }
 343
 344                 if (addr >= (sizeof(struct pt_regs))) {
 345                         ret = 0;
 346                         break;
 347                 }
 348                 if (addr == PT_SYSCFG) {
 349                         data &= SYSCFG_MASK;
 350                         data |= get_reg(child, PT_SYSCFG);
 351                 }
 352                 ret = put_reg(child, addr, data);
 353                 break;
 354
 355         case PTRACE_SYSCALL:    /* continue and stop at next (return from) syscall */
 356         case PTRACE_CONT:       /* restart after signal. */
 357                 pr_debug("ptrace: syscall/cont\n");
 358
 359                 ret = -EIO;
 360                 if (!valid_signal(data))
 361                         break;
 362                 if (request == PTRACE_SYSCALL)
 363                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 364                 else
 365                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 366                 child->exit_code = data;
 367                 ptrace_disable(child);
 368                 pr_debug("ptrace: before wake_up_process\n");
 369                 wake_up_process(child);
 370                 ret = 0;
 371                 break;
 372
 373         /*
 374          * make the child exit.  Best I can do is send it a sigkill.
 375          * perhaps it should be put in the status that it wants to
 376          * exit.
 377          */
 378         case PTRACE_KILL:
 379                 ret = 0;
 380                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 381                         break;
 382                 child->exit_code = SIGKILL;
 383                 ptrace_disable(child);
 384                 wake_up_process(child);
 385                 break;
 386
 387         case PTRACE_SINGLESTEP: /* set the trap flag. */
 388                 pr_debug("ptrace: single step\n");
 389                 ret = -EIO;
 390                 if (!valid_signal(data))
 391                         break;
 392                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 393                 ptrace_enable(child);
 394                 child->exit_code = data;
 395                 wake_up_process(child);
 396                 ret = 0;
 397                 break;
 398
 399         case PTRACE_GETREGS:
 400                 /* Get all gp regs from the child. */
 401                 ret = ptrace_getregs(child, datap);
 402                 break;
 403
 404         case PTRACE_SETREGS:
 405                 printk(KERN_WARNING "ptrace: SETREGS: **** NOT IMPLEMENTED ***\n");
 406                 /* Set all gp regs in the child. */
 407                 ret = 0;
 408                 break;
 409
 410         default:
 411                 ret = ptrace_request(child, request, addr, data);
 412                 break;
 413         }
 414
 415         return ret;
 416 }
 417
 418 asmlinkage void syscall_trace(void)
 419 {
 420         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 421                 return;
 422
 423         if (!(current->ptrace & PT_PTRACED))
 424                 return;
 425
 426         /* the 0x80 provides a way for the tracing parent to distinguish
 427          * between a syscall stop and SIGTRAP delivery
 428          */
 429         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 430                                  ? 0x80 : 0));
 431
 432         /*
 433          * this isn't the same as continuing with a signal, but it will do
 434          * for normal use.  strace only continues with a signal if the
 435          * stopping signal is not SIGTRAP.  -brl
 436          */
 437         if (current->exit_code) {
 438                 send_sig(current->exit_code, current, 1);
 439                 current->exit_code = 0;
 440         }
 441 }