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
  40 #include <asm/uaccess.h>
  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
  48 #define MAX_SHARED_LIBS 3
  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         return -EIO;
 173 }
 174
 175 /*
 176  * Called by kernel/ptrace.c when detaching..
 177  *
 178  * Make sure the single step bit is not set.
 179  */
 180 void ptrace_disable(struct task_struct *child)
 181 {
 182         unsigned long tmp;
 183         /* make sure the single step bit is not set. */
 184         tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 185         put_reg(child, PT_SR, tmp);
 186 }
 187
 188 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 189 {
 190         int ret;
 191         int add = 0;
 192
 193         switch (request) {
 194                 /* when I and D space are separate, these will need to be fixed. */
 195         case PTRACE_PEEKDATA:
 196                 pr_debug("ptrace: PEEKDATA\n");
 197                 add = MAX_SHARED_LIBS * 4;      /* space between text and data */
 198                 /* fall through */
 199         case PTRACE_PEEKTEXT:   /* read word at location addr. */
 200                 {
 201                         unsigned long tmp = 0;
 202                         int copied;
 203
 204                         ret = -EIO;
 205                         pr_debug("ptrace: PEEKTEXT at addr 0x%08lx + add %d %ld\n", addr, add,
 206                                  sizeof(data));
 207                         if (is_user_addr_valid(child, addr + add, sizeof(tmp)) < 0)
 208                                 break;
 209                         pr_debug("ptrace: user address is valid\n");
 210
 211 #if L1_CODE_LENGTH != 0
 212                         if (addr + add >= L1_CODE_START
 213                             && addr + add + sizeof(tmp) <= L1_CODE_START + L1_CODE_LENGTH) {
 214                                 safe_dma_memcpy (&tmp, (const void *)(addr + add), sizeof(tmp));
 215                                 copied = sizeof(tmp);
 216                         } else
 217 #endif
 218                         copied =
 219                             access_process_vm(child, addr + add, &tmp,
 220                                               sizeof(tmp), 0);
 221                         pr_debug("ptrace: copied size %d [0x%08lx]\n", copied, tmp);
 222                         if (copied != sizeof(tmp))
 223                                 break;
 224                         ret = put_user(tmp, (unsigned long *)data);
 225                         break;
 226                 }
 227
 228                 /* read the word at location addr in the USER area. */
 229         case PTRACE_PEEKUSR:
 230                 {
 231                         unsigned long tmp;
 232                         ret = -EIO;
 233                         tmp = 0;
 234                         if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
 235                                 printk(KERN_WARNING "ptrace error : PEEKUSR : temporarily returning "
 236                                                     "0 - %x sizeof(pt_regs) is %lx\n",
 237                                      (int)addr, sizeof(struct pt_regs));
 238                                 break;
 239                         }
 240                         if (addr == sizeof(struct pt_regs)) {
 241                                 /* PT_TEXT_ADDR */
 242                                 tmp = child->mm->start_code + TEXT_OFFSET;
 243                         } else if (addr == (sizeof(struct pt_regs) + 4)) {
 244                                 /* PT_TEXT_END_ADDR */
 245                                 tmp = child->mm->end_code;
 246                         } else if (addr == (sizeof(struct pt_regs) + 8)) {
 247                                 /* PT_DATA_ADDR */
 248                                 tmp = child->mm->start_data;
 249 #ifdef CONFIG_BINFMT_ELF_FDPIC
 250                         } else if (addr == (sizeof(struct pt_regs) + 12)) {
 251                                 tmp = child->mm->context.exec_fdpic_loadmap;
 252                         } else if (addr == (sizeof(struct pt_regs) + 16)) {
 253                                 tmp = child->mm->context.interp_fdpic_loadmap;
 254 #endif
 255                         } else {
 256                                 tmp = get_reg(child, addr);
 257                         }
 258                         ret = put_user(tmp, (unsigned long *)data);
 259                         break;
 260                 }
 261
 262                 /* when I and D space are separate, this will have to be fixed. */
 263         case PTRACE_POKEDATA:
 264                 printk(KERN_NOTICE "ptrace: PTRACE_PEEKDATA\n");
 265                 /* fall through */
 266         case PTRACE_POKETEXT:   /* write the word at location addr. */
 267                 {
 268                         int copied;
 269
 270                         ret = -EIO;
 271                         pr_debug("ptrace: POKETEXT at addr 0x%08lx + add %d %ld bytes %lx\n",
 272                                  addr, add, sizeof(data), data);
 273                         if (is_user_addr_valid(child, addr + add, sizeof(data)) < 0)
 274                                 break;
 275                         pr_debug("ptrace: user address is valid\n");
 276
 277 #if L1_CODE_LENGTH != 0
 278                         if (addr + add >= L1_CODE_START
 279                             && addr + add + sizeof(data) <= L1_CODE_START + L1_CODE_LENGTH) {
 280                                 safe_dma_memcpy ((void *)(addr + add), &data, sizeof(data));
 281                                 copied = sizeof(data);
 282                         } else
 283 #endif
 284                         copied =
 285                             access_process_vm(child, addr + add, &data,
 286                                               sizeof(data), 1);
 287                         pr_debug("ptrace: copied size %d\n", copied);
 288                         if (copied != sizeof(data))
 289                                 break;
 290                         ret = 0;
 291                         break;
 292                 }
 293
 294         case PTRACE_POKEUSR:    /* write the word at location addr in the USER area */
 295                 ret = -EIO;
 296                 if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
 297                         printk(KERN_WARNING "ptrace error : POKEUSR: temporarily returning 0\n");
 298                         break;
 299                 }
 300
 301                 if (addr >= (sizeof(struct pt_regs))) {
 302                         ret = 0;
 303                         break;
 304                 }
 305                 if (addr == PT_SYSCFG) {
 306                         data &= SYSCFG_MASK;
 307                         data |= get_reg(child, PT_SYSCFG);
 308                 }
 309                 ret = put_reg(child, addr, data);
 310                 break;
 311
 312         case PTRACE_SYSCALL:    /* continue and stop at next (return from) syscall */
 313         case PTRACE_CONT:
 314                 {               /* restart after signal. */
 315                         long tmp;
 316
 317                         pr_debug("ptrace_cont\n");
 318
 319                         ret = -EIO;
 320                         if (!valid_signal(data))
 321                                 break;
 322                         if (request == PTRACE_SYSCALL)
 323                                 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 324                         else
 325                                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 326
 327                         child->exit_code = data;
 328                         /* make sure the single step bit is not set. */
 329                         tmp = get_reg(child, PT_SYSCFG) & ~(TRACE_BITS);
 330                         put_reg(child, PT_SYSCFG, tmp);
 331                         pr_debug("before wake_up_process\n");
 332                         wake_up_process(child);
 333                         ret = 0;
 334                         break;
 335                 }
 336
 337         /*
 338          * make the child exit.  Best I can do is send it a sigkill.
 339          * perhaps it should be put in the status that it wants to
 340          * exit.
 341          */
 342         case PTRACE_KILL:
 343                 {
 344                         long tmp;
 345                         ret = 0;
 346                         if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 347                                 break;
 348                         child->exit_code = SIGKILL;
 349                         /* make sure the single step bit is not set. */
 350                         tmp = get_reg(child, PT_SYSCFG) & ~(TRACE_BITS);
 351                         put_reg(child, PT_SYSCFG, tmp);
 352                         wake_up_process(child);
 353                         break;
 354                 }
 355
 356         case PTRACE_SINGLESTEP:
 357                 {               /* set the trap flag. */
 358                         long tmp;
 359
 360                         pr_debug("single step\n");
 361                         ret = -EIO;
 362                         if (!valid_signal(data))
 363                                 break;
 364                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 365
 366                         tmp = get_reg(child, PT_SYSCFG) | (TRACE_BITS);
 367                         put_reg(child, PT_SYSCFG, tmp);
 368
 369                         child->exit_code = data;
 370                         /* give it a chance to run. */
 371                         wake_up_process(child);
 372                         ret = 0;
 373                         break;
 374                 }
 375
 376         case PTRACE_DETACH:
 377                 {               /* detach a process that was attached. */
 378                         ret = ptrace_detach(child, data);
 379                         break;
 380                 }
 381
 382         case PTRACE_GETREGS:
 383                 {
 384
 385                         /* Get all gp regs from the child. */
 386                         ret = ptrace_getregs(child, (void __user *)data);
 387                         break;
 388                 }
 389
 390         case PTRACE_SETREGS:
 391                 {
 392                         printk(KERN_NOTICE
 393                                "ptrace: SETREGS: **** NOT IMPLEMENTED ***\n");
 394                         /* Set all gp regs in the child. */
 395                         ret = 0;
 396                         break;
 397                 }
 398         default:
 399                 ret = ptrace_request(child, request, addr, data);
 400                 break;
 401         }
 402
 403         return ret;
 404 }
 405
 406 asmlinkage void syscall_trace(void)
 407 {
 408
 409         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 410                 return;
 411
 412         if (!(current->ptrace & PT_PTRACED))
 413                 return;
 414
 415         /* the 0x80 provides a way for the tracing parent to distinguish
 416          * between a syscall stop and SIGTRAP delivery
 417          */
 418         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 419                                  ? 0x80 : 0));
 420
 421         /*
 422          * this isn't the same as continuing with a signal, but it will do
 423          * for normal use.  strace only continues with a signal if the
 424          * stopping signal is not SIGTRAP.  -brl
 425          */
 426         if (current->exit_code) {
 427                 send_sig(current->exit_code, current, 1);
 428                 current->exit_code = 0;
 429         }
 430 }