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
  49 #define TEXT_OFFSET 0
  50 /*
  51  * does not yet catch signals sent when the child dies.
  52  * in exit.c or in signal.c.
  53  */
  54
  55 /* determines which bits in the SYSCFG reg the user has access to. */
  56 /* 1 = access 0 = no access */
  57 #define SYSCFG_MASK 0x0007      /* SYSCFG reg */
  58 /* sets the trace bits. */
  59 #define TRACE_BITS 0x0001
  60
  61 /* Find the stack offset for a register, relative to thread.esp0. */
  62 #define PT_REG(reg)     ((long)&((struct pt_regs *)0)->reg)
  63
  64 /*
  65  * Get the address of the live pt_regs for the specified task.
  66  * These are saved onto the top kernel stack when the process
  67  * is not running.
  68  *
  69  * Note: if a user thread is execve'd from kernel space, the
  70  * kernel stack will not be empty on entry to the kernel, so
  71  * ptracing these tasks will fail.
  72  */
  73 static inline struct pt_regs *get_user_regs(struct task_struct *task)
  74 {
  75         return (struct pt_regs *)
  76             ((unsigned long)task_stack_page(task) +
  77              (THREAD_SIZE - sizeof(struct pt_regs)));
  78 }
  79
  80 /*
  81  * Get all user integer registers.
  82  */
  83 static inline int ptrace_getregs(struct task_struct *tsk, void __user * uregs)
  84 {
  85         struct pt_regs *regs = get_user_regs(tsk);
  86         return copy_to_user(uregs, regs, sizeof(struct pt_regs)) ? -EFAULT : 0;
  87 }
  88
  89 /* Mapping from PT_xxx to the stack offset at which the register is
  90  * saved.  Notice that usp has no stack-slot and needs to be treated
  91  * specially (see get_reg/put_reg below).
  92  */
  93
  94 /*
  95  * Get contents of register REGNO in task TASK.
  96  */
  97 static inline long get_reg(struct task_struct *task, int regno)
  98 {
  99         unsigned char *reg_ptr;
 100
 101         struct pt_regs *regs =
 102             (struct pt_regs *)((unsigned long)task_stack_page(task) +
 103                                (THREAD_SIZE - sizeof(struct pt_regs)));
 104         reg_ptr = (char *)regs;
 105
 106         switch (regno) {
 107         case PT_USP:
 108                 return task->thread.usp;
 109         default:
 110                 if (regno <= 216)
 111                         return *(long *)(reg_ptr + regno);
 112         }
 113         /* slight mystery ... never seems to come here but kernel misbehaves without this code! */
 114
 115         printk(KERN_WARNING "Request to get for unknown register %d\n", regno);
 116         return 0;
 117 }
 118
 119 /*
 120  * Write contents of register REGNO in task TASK.
 121  */
 122 static inline int
 123 put_reg(struct task_struct *task, int regno, unsigned long data)
 124 {
 125         char *reg_ptr;
 126
 127         struct pt_regs *regs =
 128             (struct pt_regs *)((unsigned long)task_stack_page(task) +
 129                                (THREAD_SIZE - sizeof(struct pt_regs)));
 130         reg_ptr = (char *)regs;
 131
 132         switch (regno) {
 133         case PT_PC:
 134                 /*********************************************************************/
 135                 /* At this point the kernel is most likely in exception.             */
 136                 /* The RETX register will be used to populate the pc of the process. */
 137                 /*********************************************************************/
 138                 regs->retx = data;
 139                 regs->pc = data;
 140                 break;
 141         case PT_RETX:
 142                 break;          /* regs->retx = data; break; */
 143         case PT_USP:
 144                 regs->usp = data;
 145                 task->thread.usp = data;
 146                 break;
 147         default:
 148                 if (regno <= 216)
 149                         *(long *)(reg_ptr + regno) = data;
 150         }
 151         return 0;
 152 }
 153
 154 /*
 155  * check that an address falls within the bounds of the target process's memory mappings
 156  */
 157 static inline int is_user_addr_valid(struct task_struct *child,
 158                                      unsigned long start, unsigned long len)
 159 {
 160         struct vm_list_struct *vml;
 161         struct sram_list_struct *sraml;
 162
 163         for (vml = child->mm->context.vmlist; vml; vml = vml->next)
 164                 if (start >= vml->vma->vm_start && start + len <= vml->vma->vm_end)
 165                         return 0;
 166
 167         for (sraml = child->mm->context.sram_list; sraml; sraml = sraml->next)
 168                 if (start >= (unsigned long)sraml->addr
 169                     && start + len <= (unsigned long)sraml->addr + sraml->length)
 170                         return 0;
 171
 172         if (start >= FIXED_CODE_START && start + len <= FIXED_CODE_END)
 173                 return 0;
 174
 175         return -EIO;
 176 }
 177
 178 /*
 179  * Called by kernel/ptrace.c when detaching..
 180  *
 181  * Make sure the single step bit is not set.
 182  */
 183 void ptrace_disable(struct task_struct *child)
 184 {
 185         unsigned long tmp;
 186         /* make sure the single step bit is not set. */
 187         tmp = get_reg(child, PT_SYSCFG) & ~TRACE_BITS;
 188         put_reg(child, PT_SYSCFG, tmp);
 189 }
 190
 191 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 192 {
 193         int ret;
 194         unsigned long __user *datap = (unsigned long __user *)data;
 195
 196         switch (request) {
 197                 /* when I and D space are separate, these will need to be fixed. */
 198         case PTRACE_PEEKDATA:
 199                 pr_debug("ptrace: PEEKDATA\n");
 200                 /* fall through */
 201         case PTRACE_PEEKTEXT:   /* read word at location addr. */
 202                 {
 203                         unsigned long tmp = 0;
 204                         int copied;
 205
 206                         ret = -EIO;
 207                         pr_debug("ptrace: PEEKTEXT at addr 0x%08lx + %ld\n", addr, sizeof(data));
 208                         if (is_user_addr_valid(child, addr, sizeof(tmp)) < 0)
 209                                 break;
 210                         pr_debug("ptrace: user address is valid\n");
 211
 212 #if L1_CODE_LENGTH != 0
 213                         if (addr >= L1_CODE_START
 214                             && addr + sizeof(tmp) <= L1_CODE_START + L1_CODE_LENGTH) {
 215                                 safe_dma_memcpy (&tmp, (const void *)(addr), sizeof(tmp));
 216                                 copied = sizeof(tmp);
 217                         } else
 218 #endif
 219 #if L1_DATA_A_LENGTH != 0
 220                         if (addr >= L1_DATA_A_START
 221                             && addr + sizeof(tmp) <= L1_DATA_A_START + L1_DATA_A_LENGTH) {
 222                                 memcpy(&tmp, (const void *)(addr), sizeof(tmp));
 223                                 copied = sizeof(tmp);
 224                         } else
 225 #endif
 226 #if L1_DATA_B_LENGTH != 0
 227                         if (addr >= L1_DATA_B_START
 228                             && addr + sizeof(tmp) <= L1_DATA_B_START + L1_DATA_B_LENGTH) {
 229                                 memcpy(&tmp, (const void *)(addr), sizeof(tmp));
 230                                 copied = sizeof(tmp);
 231                         } else
 232 #endif
 233                         if (addr >= FIXED_CODE_START
 234                             && addr + sizeof(tmp) <= FIXED_CODE_END) {
 235                                 memcpy(&tmp, (const void *)(addr), sizeof(tmp));
 236                                 copied = sizeof(tmp);
 237                         } else
 238                                 copied = access_process_vm(child, addr, &tmp,
 239                                                            sizeof(tmp), 0);
 240                         pr_debug("ptrace: copied size %d [0x%08lx]\n", copied, tmp);
 241                         if (copied != sizeof(tmp))
 242                                 break;
 243                         ret = put_user(tmp, datap);
 244                         break;
 245                 }
 246
 247                 /* read the word at location addr in the USER area. */
 248         case PTRACE_PEEKUSR:
 249                 {
 250                         unsigned long tmp;
 251                         ret = -EIO;
 252                         tmp = 0;
 253                         if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
 254                                 printk(KERN_WARNING "ptrace error : PEEKUSR : temporarily returning "
 255                                                     "0 - %x sizeof(pt_regs) is %lx\n",
 256                                      (int)addr, sizeof(struct pt_regs));
 257                                 break;
 258                         }
 259                         if (addr == sizeof(struct pt_regs)) {
 260                                 /* PT_TEXT_ADDR */
 261                                 tmp = child->mm->start_code + TEXT_OFFSET;
 262                         } else if (addr == (sizeof(struct pt_regs) + 4)) {
 263                                 /* PT_TEXT_END_ADDR */
 264                                 tmp = child->mm->end_code;
 265                         } else if (addr == (sizeof(struct pt_regs) + 8)) {
 266                                 /* PT_DATA_ADDR */
 267                                 tmp = child->mm->start_data;
 268 #ifdef CONFIG_BINFMT_ELF_FDPIC
 269                         } else if (addr == (sizeof(struct pt_regs) + 12)) {
 270                                 tmp = child->mm->context.exec_fdpic_loadmap;
 271                         } else if (addr == (sizeof(struct pt_regs) + 16)) {
 272                                 tmp = child->mm->context.interp_fdpic_loadmap;
 273 #endif
 274                         } else {
 275                                 tmp = get_reg(child, addr);
 276                         }
 277                         ret = put_user(tmp, datap);
 278                         break;
 279                 }
 280
 281                 /* when I and D space are separate, this will have to be fixed. */
 282         case PTRACE_POKEDATA:
 283                 pr_debug("ptrace: PTRACE_PEEKDATA\n");
 284                 /* fall through */
 285         case PTRACE_POKETEXT:   /* write the word at location addr. */
 286                 {
 287                         int copied;
 288
 289                         ret = -EIO;
 290                         pr_debug("ptrace: POKETEXT at addr 0x%08lx + %ld bytes %lx\n",
 291                                  addr, sizeof(data), data);
 292                         if (is_user_addr_valid(child, addr, sizeof(data)) < 0)
 293                                 break;
 294                         pr_debug("ptrace: user address is valid\n");
 295
 296 #if L1_CODE_LENGTH != 0
 297                         if (addr >= L1_CODE_START
 298                             && addr + sizeof(data) <= L1_CODE_START + L1_CODE_LENGTH) {
 299                                 safe_dma_memcpy ((void *)(addr), &data, sizeof(data));
 300                                 copied = sizeof(data);
 301                         } else
 302 #endif
 303 #if L1_DATA_A_LENGTH != 0
 304                         if (addr >= L1_DATA_A_START
 305                             && addr + sizeof(data) <= L1_DATA_A_START + L1_DATA_A_LENGTH) {
 306                                 memcpy((void *)(addr), &data, sizeof(data));
 307                                 copied = sizeof(data);
 308                         } else
 309 #endif
 310 #if L1_DATA_B_LENGTH != 0
 311                         if (addr >= L1_DATA_B_START
 312                             && addr + sizeof(data) <= L1_DATA_B_START + L1_DATA_B_LENGTH) {
 313                                 memcpy((void *)(addr), &data, sizeof(data));
 314                                 copied = sizeof(data);
 315                         } else
 316 #endif
 317                         if (addr >= FIXED_CODE_START
 318                             && addr + sizeof(data) <= FIXED_CODE_END) {
 319                                 memcpy((void *)(addr), &data, sizeof(data));
 320                                 copied = sizeof(data);
 321                         } else
 322                                 copied = access_process_vm(child, addr, &data,
 323                                                            sizeof(data), 1);
 324                         pr_debug("ptrace: copied size %d\n", copied);
 325                         if (copied != sizeof(data))
 326                                 break;
 327                         ret = 0;
 328                         break;
 329                 }
 330
 331         case PTRACE_POKEUSR:    /* write the word at location addr in the USER area */
 332                 ret = -EIO;
 333                 if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
 334                         printk(KERN_WARNING "ptrace error : POKEUSR: temporarily returning 0\n");
 335                         break;
 336                 }
 337
 338                 if (addr >= (sizeof(struct pt_regs))) {
 339                         ret = 0;
 340                         break;
 341                 }
 342                 if (addr == PT_SYSCFG) {
 343                         data &= SYSCFG_MASK;
 344                         data |= get_reg(child, PT_SYSCFG);
 345                 }
 346                 ret = put_reg(child, addr, data);
 347                 break;
 348
 349         case PTRACE_SYSCALL:    /* continue and stop at next (return from) syscall */
 350         case PTRACE_CONT:
 351                 {               /* restart after signal. */
 352                         long tmp;
 353
 354                         pr_debug("ptrace: syscall/cont\n");
 355
 356                         ret = -EIO;
 357                         if (!valid_signal(data))
 358                                 break;
 359                         if (request == PTRACE_SYSCALL)
 360                                 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 361                         else
 362                                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 363
 364                         child->exit_code = data;
 365                         /* make sure the single step bit is not set. */
 366                         tmp = get_reg(child, PT_SYSCFG) & ~(TRACE_BITS);
 367                         put_reg(child, PT_SYSCFG, tmp);
 368                         pr_debug("ptrace: before wake_up_process\n");
 369                         wake_up_process(child);
 370                         ret = 0;
 371                         break;
 372                 }
 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                 {
 381                         long tmp;
 382                         ret = 0;
 383                         if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 384                                 break;
 385                         child->exit_code = SIGKILL;
 386                         /* make sure the single step bit is not set. */
 387                         tmp = get_reg(child, PT_SYSCFG) & ~(TRACE_BITS);
 388                         put_reg(child, PT_SYSCFG, tmp);
 389                         wake_up_process(child);
 390                         break;
 391                 }
 392
 393         case PTRACE_SINGLESTEP:
 394                 {               /* set the trap flag. */
 395                         long tmp;
 396
 397                         pr_debug("ptrace: single step\n");
 398                         ret = -EIO;
 399                         if (!valid_signal(data))
 400                                 break;
 401                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 402
 403                         tmp = get_reg(child, PT_SYSCFG) | (TRACE_BITS);
 404                         put_reg(child, PT_SYSCFG, tmp);
 405
 406                         child->exit_code = data;
 407                         /* give it a chance to run. */
 408                         wake_up_process(child);
 409                         ret = 0;
 410                         break;
 411                 }
 412
 413         case PTRACE_GETREGS:
 414                 /* Get all gp regs from the child. */
 415                 ret = ptrace_getregs(child, datap);
 416                 break;
 417
 418         case PTRACE_SETREGS:
 419                 printk(KERN_WARNING "ptrace: SETREGS: **** NOT IMPLEMENTED ***\n");
 420                 /* Set all gp regs in the child. */
 421                 ret = 0;
 422                 break;
 423
 424         default:
 425                 ret = ptrace_request(child, request, addr, data);
 426                 break;
 427         }
 428
 429         return ret;
 430 }
 431
 432 asmlinkage void syscall_trace(void)
 433 {
 434         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 435                 return;
 436
 437         if (!(current->ptrace & PT_PTRACED))
 438                 return;
 439
 440         /* the 0x80 provides a way for the tracing parent to distinguish
 441          * between a syscall stop and SIGTRAP delivery
 442          */
 443         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 444                                  ? 0x80 : 0));
 445
 446         /*
 447          * this isn't the same as continuing with a signal, but it will do
 448          * for normal use.  strace only continues with a signal if the
 449          * stopping signal is not SIGTRAP.  -brl
 450          */
 451         if (current->exit_code) {
 452                 send_sig(current->exit_code, current, 1);
 453                 current->exit_code = 0;
 454         }
 455 }