arch/mips/kernel/syscall.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 1995, 1996, 1997, 2000, 2001, 05 by Ralf Baechle
   7  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
   8  * Copyright (C) 2001 MIPS Technologies, Inc.
   9  */
  10 #include <linux/capability.h>
  11 #include <linux/errno.h>
  12 #include <linux/linkage.h>
  13 #include <linux/mm.h>
  14 #include <linux/fs.h>
  15 #include <linux/smp.h>
  16 #include <linux/mman.h>
  17 #include <linux/ptrace.h>
  18 #include <linux/sched.h>
  19 #include <linux/string.h>
  20 #include <linux/syscalls.h>
  21 #include <linux/file.h>
  22 #include <linux/slab.h>
  23 #include <linux/utsname.h>
  24 #include <linux/unistd.h>
  25 #include <linux/sem.h>
  26 #include <linux/msg.h>
  27 #include <linux/shm.h>
  28 #include <linux/compiler.h>
  29 #include <linux/module.h>
  30 #include <linux/ipc.h>
  31 #include <linux/uaccess.h>
  32
  33 #include <asm/asm.h>
  34 #include <asm/branch.h>
  35 #include <asm/cachectl.h>
  36 #include <asm/cacheflush.h>
  37 #include <asm/asm-offsets.h>
  38 #include <asm/signal.h>
  39 #include <asm/sim.h>
  40 #include <asm/shmparam.h>
  41 #include <asm/sysmips.h>
  42 #include <asm/uaccess.h>
  43
  44 /*
  45  * For historic reasons the pipe(2) syscall on MIPS has an unusual calling
  46  * convention.  It returns results in registers $v0 / $v1 which means there
  47  * is no need for it to do verify the validity of a userspace pointer
  48  * argument.  Historically that used to be expensive in Linux.  These days
  49  * the performance advantage is negligible.
  50  */
  51 asmlinkage int sysm_pipe(nabi_no_regargs volatile struct pt_regs regs)
  52 {
  53         int fd[2];
  54         int error, res;
  55
  56         error = do_pipe_flags(fd, 0);
  57         if (error) {
  58                 res = error;
  59                 goto out;
  60         }
  61         regs.regs[3] = fd[1];
  62         res = fd[0];
  63 out:
  64         return res;
  65 }
  66
  67 unsigned long shm_align_mask = PAGE_SIZE - 1;   /* Sane caches */
  68
  69 EXPORT_SYMBOL(shm_align_mask);
  70
  71 #define COLOUR_ALIGN(addr,pgoff)                                \
  72         ((((addr) + shm_align_mask) & ~shm_align_mask) +        \
  73          (((pgoff) << PAGE_SHIFT) & shm_align_mask))
  74
  75 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
  76         unsigned long len, unsigned long pgoff, unsigned long flags)
  77 {
  78         struct vm_area_struct * vmm;
  79         int do_color_align;
  80         unsigned long task_size;
  81
  82         task_size = STACK_TOP;
  83
  84         if (len > task_size)
  85                 return -ENOMEM;
  86
  87         if (flags & MAP_FIXED) {
  88                 /* Even MAP_FIXED mappings must reside within task_size.  */
  89                 if (task_size - len < addr)
  90                         return -EINVAL;
  91
  92                 /*
  93                  * We do not accept a shared mapping if it would violate
  94                  * cache aliasing constraints.
  95                  */
  96                 if ((flags & MAP_SHARED) && (addr & shm_align_mask))
  97                         return -EINVAL;
  98                 return addr;
  99         }
 100
 101         do_color_align = 0;
 102         if (filp || (flags & MAP_SHARED))
 103                 do_color_align = 1;
 104         if (addr) {
 105                 if (do_color_align)
 106                         addr = COLOUR_ALIGN(addr, pgoff);
 107                 else
 108                         addr = PAGE_ALIGN(addr);
 109                 vmm = find_vma(current->mm, addr);
 110                 if (task_size - len >= addr &&
 111                     (!vmm || addr + len <= vmm->vm_start))
 112                         return addr;
 113         }
 114         addr = TASK_UNMAPPED_BASE;
 115         if (do_color_align)
 116                 addr = COLOUR_ALIGN(addr, pgoff);
 117         else
 118                 addr = PAGE_ALIGN(addr);
 119
 120         for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
 121                 /* At this point:  (!vmm || addr < vmm->vm_end). */
 122                 if (task_size - len < addr)
 123                         return -ENOMEM;
 124                 if (!vmm || addr + len <= vmm->vm_start)
 125                         return addr;
 126                 addr = vmm->vm_end;
 127                 if (do_color_align)
 128                         addr = COLOUR_ALIGN(addr, pgoff);
 129         }
 130 }
 131
 132 /* common code for old and new mmaps */
 133 static inline unsigned long
 134 do_mmap2(unsigned long addr, unsigned long len, unsigned long prot,
 135         unsigned long flags, unsigned long fd, unsigned long pgoff)
 136 {
 137         unsigned long error = -EBADF;
 138         struct file * file = NULL;
 139
 140         flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
 141         if (!(flags & MAP_ANONYMOUS)) {
 142                 file = fget(fd);
 143                 if (!file)
 144                         goto out;
 145         }
 146
 147         down_write(&current->mm->mmap_sem);
 148         error = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
 149         up_write(&current->mm->mmap_sem);
 150
 151         if (file)
 152                 fput(file);
 153 out:
 154         return error;
 155 }
 156
 157 SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
 158         unsigned long, prot, unsigned long, flags, unsigned long,
 159         fd, off_t, offset)
 160 {
 161         unsigned long result;
 162
 163         result = -EINVAL;
 164         if (offset & ~PAGE_MASK)
 165                 goto out;
 166
 167         result = do_mmap2(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
 168
 169 out:
 170         return result;
 171 }
 172
 173 SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
 174         unsigned long, prot, unsigned long, flags, unsigned long, fd,
 175         unsigned long, pgoff)
 176 {
 177         if (pgoff & (~PAGE_MASK >> 12))
 178                 return -EINVAL;
 179
 180         return do_mmap2(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
 181 }
 182
 183 save_static_function(sys_fork);
 184 static int __used noinline
 185 _sys_fork(nabi_no_regargs struct pt_regs regs)
 186 {
 187         return do_fork(SIGCHLD, regs.regs[29], &regs, 0, NULL, NULL);
 188 }
 189
 190 save_static_function(sys_clone);
 191 static int __used noinline
 192 _sys_clone(nabi_no_regargs struct pt_regs regs)
 193 {
 194         unsigned long clone_flags;
 195         unsigned long newsp;
 196         int __user *parent_tidptr, *child_tidptr;
 197
 198         clone_flags = regs.regs[4];
 199         newsp = regs.regs[5];
 200         if (!newsp)
 201                 newsp = regs.regs[29];
 202         parent_tidptr = (int __user *) regs.regs[6];
 203 #ifdef CONFIG_32BIT
 204         /* We need to fetch the fifth argument off the stack.  */
 205         child_tidptr = NULL;
 206         if (clone_flags & (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)) {
 207                 int __user *__user *usp = (int __user *__user *) regs.regs[29];
 208                 if (regs.regs[2] == __NR_syscall) {
 209                         if (get_user (child_tidptr, &usp[5]))
 210                                 return -EFAULT;
 211                 }
 212                 else if (get_user (child_tidptr, &usp[4]))
 213                         return -EFAULT;
 214         }
 215 #else
 216         child_tidptr = (int __user *) regs.regs[8];
 217 #endif
 218         return do_fork(clone_flags, newsp, &regs, 0,
 219                        parent_tidptr, child_tidptr);
 220 }
 221
 222 /*
 223  * sys_execve() executes a new program.
 224  */
 225 asmlinkage int sys_execve(nabi_no_regargs struct pt_regs regs)
 226 {
 227         int error;
 228         char * filename;
 229
 230         filename = getname((char __user *) (long)regs.regs[4]);
 231         error = PTR_ERR(filename);
 232         if (IS_ERR(filename))
 233                 goto out;
 234         error = do_execve(filename, (char __user *__user *) (long)regs.regs[5],
 235                           (char __user *__user *) (long)regs.regs[6], &regs);
 236         putname(filename);
 237
 238 out:
 239         return error;
 240 }
 241
 242 /*
 243  * Compacrapability ...
 244  */
 245 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
 246 {
 247         if (name && !copy_to_user(name, utsname(), sizeof (*name)))
 248                 return 0;
 249         return -EFAULT;
 250 }
 251
 252 /*
 253  * Compacrapability ...
 254  */
 255 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
 256 {
 257         int error;
 258
 259         if (!name)
 260                 return -EFAULT;
 261         if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
 262                 return -EFAULT;
 263
 264         error = __copy_to_user(&name->sysname, &utsname()->sysname,
 265                                __OLD_UTS_LEN);
 266         error -= __put_user(0, name->sysname + __OLD_UTS_LEN);
 267         error -= __copy_to_user(&name->nodename, &utsname()->nodename,
 268                                 __OLD_UTS_LEN);
 269         error -= __put_user(0, name->nodename + __OLD_UTS_LEN);
 270         error -= __copy_to_user(&name->release, &utsname()->release,
 271                                 __OLD_UTS_LEN);
 272         error -= __put_user(0, name->release + __OLD_UTS_LEN);
 273         error -= __copy_to_user(&name->version, &utsname()->version,
 274                                 __OLD_UTS_LEN);
 275         error -= __put_user(0, name->version + __OLD_UTS_LEN);
 276         error -= __copy_to_user(&name->machine, &utsname()->machine,
 277                                 __OLD_UTS_LEN);
 278         error = __put_user(0, name->machine + __OLD_UTS_LEN);
 279         error = error ? -EFAULT : 0;
 280
 281         return error;
 282 }
 283
 284 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
 285 {
 286         struct thread_info *ti = task_thread_info(current);
 287
 288         ti->tp_value = addr;
 289         if (cpu_has_userlocal)
 290                 write_c0_userlocal(addr);
 291
 292         return 0;
 293 }
 294
 295 static inline int mips_atomic_set(struct pt_regs *regs,
 296         unsigned long addr, unsigned long new)
 297 {
 298         unsigned long old, tmp;
 299         unsigned int err;
 300
 301         if (unlikely(addr & 3))
 302                 return -EINVAL;
 303
 304         if (unlikely(!access_ok(VERIFY_WRITE, addr, 4)))
 305                 return -EINVAL;
 306
 307         if (cpu_has_llsc && R10000_LLSC_WAR) {
 308                 __asm__ __volatile__ (
 309                 "       li      %[err], 0                               \n"
 310                 "1:     ll      %[old], (%[addr])                       \n"
 311                 "       move    %[tmp], %[new]                          \n"
 312                 "2:     sc      %[tmp], (%[addr])                       \n"
 313                 "       beqzl   %[tmp], 1b                              \n"
 314                 "3:                                                     \n"
 315                 "       .section .fixup,\"ax\"                          \n"
 316                 "4:     li      %[err], %[efault]                       \n"
 317                 "       j       3b                                      \n"
 318                 "       .previous                                       \n"
 319                 "       .section __ex_table,\"a\"                       \n"
 320                 "       "STR(PTR)"      1b, 4b                          \n"
 321                 "       "STR(PTR)"      2b, 4b                          \n"
 322                 "       .previous                                       \n"
 323                 : [old] "=&r" (old),
 324                   [err] "=&r" (err),
 325                   [tmp] "=&r" (tmp)
 326                 : [addr] "r" (addr),
 327                   [new] "r" (new),
 328                   [efault] "i" (-EFAULT)
 329                 : "memory");
 330         } else if (cpu_has_llsc) {
 331                 __asm__ __volatile__ (
 332                 "       li      %[err], 0                               \n"
 333                 "1:     ll      %[old], (%[addr])                       \n"
 334                 "       move    %[tmp], %[new]                          \n"
 335                 "2:     sc      %[tmp], (%[addr])                       \n"
 336                 "       bnez    %[tmp], 4f                              \n"
 337                 "3:                                                     \n"
 338                 "       .subsection 2                                   \n"
 339                 "4:     b       1b                                      \n"
 340                 "       .previous                                       \n"
 341                 "                                                       \n"
 342                 "       .section .fixup,\"ax\"                          \n"
 343                 "5:     li      %[err], %[efault]                       \n"
 344                 "       j       3b                                      \n"
 345                 "       .previous                                       \n"
 346                 "       .section __ex_table,\"a\"                       \n"
 347                 "       "STR(PTR)"      1b, 5b                          \n"
 348                 "       "STR(PTR)"      2b, 5b                          \n"
 349                 "       .previous                                       \n"
 350                 : [old] "=&r" (old),
 351                   [err] "=&r" (err),
 352                   [tmp] "=&r" (tmp)
 353                 : [addr] "r" (addr),
 354                   [new] "r" (new),
 355                   [efault] "i" (-EFAULT)
 356                 : "memory");
 357         } else {
 358                 do {
 359                         preempt_disable();
 360                         ll_bit = 1;
 361                         ll_task = current;
 362                         preempt_enable();
 363
 364                         err = __get_user(old, (unsigned int *) addr);
 365                         err |= __put_user(new, (unsigned int *) addr);
 366                         if (err)
 367                                 break;
 368                         rmb();
 369                 } while (!ll_bit);
 370         }
 371
 372         if (unlikely(err))
 373                 return err;
 374
 375         regs->regs[2] = old;
 376         regs->regs[7] = 0;      /* No error */
 377
 378         /*
 379          * Don't let your children do this ...
 380          */
 381         __asm__ __volatile__(
 382         "       move    $29, %0                                         \n"
 383         "       j       syscall_exit                                    \n"
 384         : /* no outputs */
 385         : "r" (regs));
 386
 387         /* unreached.  Honestly.  */
 388         while (1);
 389 }
 390
 391 save_static_function(sys_sysmips);
 392 static int __used noinline
 393 _sys_sysmips(nabi_no_regargs struct pt_regs regs)
 394 {
 395         long cmd, arg1, arg2, arg3;
 396
 397         cmd = regs.regs[4];
 398         arg1 = regs.regs[5];
 399         arg2 = regs.regs[6];
 400         arg3 = regs.regs[7];
 401
 402         switch (cmd) {
 403         case MIPS_ATOMIC_SET:
 404                 return mips_atomic_set(&regs, arg1, arg2);
 405
 406         case MIPS_FIXADE:
 407                 if (arg1 & ~3)
 408                         return -EINVAL;
 409
 410                 if (arg1 & 1)
 411                         set_thread_flag(TIF_FIXADE);
 412                 else
 413                         clear_thread_flag(TIF_FIXADE);
 414                 if (arg1 & 2)
 415                         set_thread_flag(TIF_LOGADE);
 416                 else
 417                         clear_thread_flag(TIF_FIXADE);
 418
 419                 return 0;
 420
 421         case FLUSH_CACHE:
 422                 __flush_cache_all();
 423                 return 0;
 424         }
 425
 426         return -EINVAL;
 427 }
 428
 429 /*
 430  * sys_ipc() is the de-multiplexer for the SysV IPC calls..
 431  *
 432  * This is really horribly ugly.
 433  */
 434 SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, int, second,
 435         unsigned long, third, void __user *, ptr, long, fifth)
 436 {
 437         int version, ret;
 438
 439         version = call >> 16; /* hack for backward compatibility */
 440         call &= 0xffff;
 441
 442         switch (call) {
 443         case SEMOP:
 444                 return sys_semtimedop(first, (struct sembuf __user *)ptr,
 445                                       second, NULL);
 446         case SEMTIMEDOP:
 447                 return sys_semtimedop(first, (struct sembuf __user *)ptr,
 448                                       second,
 449                                       (const struct timespec __user *)fifth);
 450         case SEMGET:
 451                 return sys_semget(first, second, third);
 452         case SEMCTL: {
 453                 union semun fourth;
 454                 if (!ptr)
 455                         return -EINVAL;
 456                 if (get_user(fourth.__pad, (void __user *__user *) ptr))
 457                         return -EFAULT;
 458                 return sys_semctl(first, second, third, fourth);
 459         }
 460
 461         case MSGSND:
 462                 return sys_msgsnd(first, (struct msgbuf __user *) ptr,
 463                                   second, third);
 464         case MSGRCV:
 465                 switch (version) {
 466                 case 0: {
 467                         struct ipc_kludge tmp;
 468                         if (!ptr)
 469                                 return -EINVAL;
 470
 471                         if (copy_from_user(&tmp,
 472                                            (struct ipc_kludge __user *) ptr,
 473                                            sizeof(tmp)))
 474                                 return -EFAULT;
 475                         return sys_msgrcv(first, tmp.msgp, second,
 476                                           tmp.msgtyp, third);
 477                 }
 478                 default:
 479                         return sys_msgrcv(first,
 480                                           (struct msgbuf __user *) ptr,
 481                                           second, fifth, third);
 482                 }
 483         case MSGGET:
 484                 return sys_msgget((key_t) first, second);
 485         case MSGCTL:
 486                 return sys_msgctl(first, second,
 487                                   (struct msqid_ds __user *) ptr);
 488
 489         case SHMAT:
 490                 switch (version) {
 491                 default: {
 492                         unsigned long raddr;
 493                         ret = do_shmat(first, (char __user *) ptr, second,
 494                                        &raddr);
 495                         if (ret)
 496                                 return ret;
 497                         return put_user(raddr, (unsigned long __user *) third);
 498                 }
 499                 case 1: /* iBCS2 emulator entry point */
 500                         if (!segment_eq(get_fs(), get_ds()))
 501                                 return -EINVAL;
 502                         return do_shmat(first, (char __user *) ptr, second,
 503                                         (unsigned long *) third);
 504                 }
 505         case SHMDT:
 506                 return sys_shmdt((char __user *)ptr);
 507         case SHMGET:
 508                 return sys_shmget(first, second, third);
 509         case SHMCTL:
 510                 return sys_shmctl(first, second,
 511                                   (struct shmid_ds __user *) ptr);
 512         default:
 513                 return -ENOSYS;
 514         }
 515 }
 516
 517 /*
 518  * No implemented yet ...
 519  */
 520 SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
 521 {
 522         return -ENOSYS;
 523 }
 524
 525 /*
 526  * If we ever come here the user sp is bad.  Zap the process right away.
 527  * Due to the bad stack signaling wouldn't work.
 528  */
 529 asmlinkage void bad_stack(void)
 530 {
 531         do_exit(SIGSEGV);
 532 }
 533
 534 /*
 535  * Do a system call from kernel instead of calling sys_execve so we
 536  * end up with proper pt_regs.
 537  */
 538 int kernel_execve(const char *filename, char *const argv[], char *const envp[])
 539 {
 540         register unsigned long __a0 asm("$4") = (unsigned long) filename;
 541         register unsigned long __a1 asm("$5") = (unsigned long) argv;
 542         register unsigned long __a2 asm("$6") = (unsigned long) envp;
 543         register unsigned long __a3 asm("$7");
 544         unsigned long __v0;
 545
 546         __asm__ volatile ("                                     \n"
 547         "       .set    noreorder                               \n"
 548         "       li      $2, %5          # __NR_execve           \n"
 549         "       syscall                                         \n"
 550         "       move    %0, $2                                  \n"
 551         "       .set    reorder                                 \n"
 552         : "=&r" (__v0), "=r" (__a3)
 553         : "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_execve)
 554         : "$2", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24",
 555           "memory");
 556
 557         if (__a3 == 0)
 558                 return __v0;
 559
 560         return -__v0;
 561 }