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                 "       .set    mips3                                   \n"
 310                 "       li      %[err], 0                               \n"
 311                 "1:     ll      %[old], (%[addr])                       \n"
 312                 "       move    %[tmp], %[new]                          \n"
 313                 "2:     sc      %[tmp], (%[addr])                       \n"
 314                 "       beqzl   %[tmp], 1b                              \n"
 315                 "3:                                                     \n"
 316                 "       .section .fixup,\"ax\"                          \n"
 317                 "4:     li      %[err], %[efault]                       \n"
 318                 "       j       3b                                      \n"
 319                 "       .previous                                       \n"
 320                 "       .section __ex_table,\"a\"                       \n"
 321                 "       "STR(PTR)"      1b, 4b                          \n"
 322                 "       "STR(PTR)"      2b, 4b                          \n"
 323                 "       .previous                                       \n"
 324                 "       .set    mips0                                   \n"
 325                 : [old] "=&r" (old),
 326                   [err] "=&r" (err),
 327                   [tmp] "=&r" (tmp)
 328                 : [addr] "r" (addr),
 329                   [new] "r" (new),
 330                   [efault] "i" (-EFAULT)
 331                 : "memory");
 332         } else if (cpu_has_llsc) {
 333                 __asm__ __volatile__ (
 334                 "       .set    mips3                                   \n"
 335                 "       li      %[err], 0                               \n"
 336                 "1:     ll      %[old], (%[addr])                       \n"
 337                 "       move    %[tmp], %[new]                          \n"
 338                 "2:     sc      %[tmp], (%[addr])                       \n"
 339                 "       bnez    %[tmp], 4f                              \n"
 340                 "3:                                                     \n"
 341                 "       .subsection 2                                   \n"
 342                 "4:     b       1b                                      \n"
 343                 "       .previous                                       \n"
 344                 "                                                       \n"
 345                 "       .section .fixup,\"ax\"                          \n"
 346                 "5:     li      %[err], %[efault]                       \n"
 347                 "       j       3b                                      \n"
 348                 "       .previous                                       \n"
 349                 "       .section __ex_table,\"a\"                       \n"
 350                 "       "STR(PTR)"      1b, 5b                          \n"
 351                 "       "STR(PTR)"      2b, 5b                          \n"
 352                 "       .previous                                       \n"
 353                 "       .set    mips0                                   \n"
 354                 : [old] "=&r" (old),
 355                   [err] "=&r" (err),
 356                   [tmp] "=&r" (tmp)
 357                 : [addr] "r" (addr),
 358                   [new] "r" (new),
 359                   [efault] "i" (-EFAULT)
 360                 : "memory");
 361         } else {
 362                 do {
 363                         preempt_disable();
 364                         ll_bit = 1;
 365                         ll_task = current;
 366                         preempt_enable();
 367
 368                         err = __get_user(old, (unsigned int *) addr);
 369                         err |= __put_user(new, (unsigned int *) addr);
 370                         if (err)
 371                                 break;
 372                         rmb();
 373                 } while (!ll_bit);
 374         }
 375
 376         if (unlikely(err))
 377                 return err;
 378
 379         regs->regs[2] = old;
 380         regs->regs[7] = 0;      /* No error */
 381
 382         /*
 383          * Don't let your children do this ...
 384          */
 385         __asm__ __volatile__(
 386         "       move    $29, %0                                         \n"
 387         "       j       syscall_exit                                    \n"
 388         : /* no outputs */
 389         : "r" (regs));
 390
 391         /* unreached.  Honestly.  */
 392         while (1);
 393 }
 394
 395 save_static_function(sys_sysmips);
 396 static int __used noinline
 397 _sys_sysmips(nabi_no_regargs struct pt_regs regs)
 398 {
 399         long cmd, arg1, arg2, arg3;
 400
 401         cmd = regs.regs[4];
 402         arg1 = regs.regs[5];
 403         arg2 = regs.regs[6];
 404         arg3 = regs.regs[7];
 405
 406         switch (cmd) {
 407         case MIPS_ATOMIC_SET:
 408                 return mips_atomic_set(&regs, arg1, arg2);
 409
 410         case MIPS_FIXADE:
 411                 if (arg1 & ~3)
 412                         return -EINVAL;
 413
 414                 if (arg1 & 1)
 415                         set_thread_flag(TIF_FIXADE);
 416                 else
 417                         clear_thread_flag(TIF_FIXADE);
 418                 if (arg1 & 2)
 419                         set_thread_flag(TIF_LOGADE);
 420                 else
 421                         clear_thread_flag(TIF_FIXADE);
 422
 423                 return 0;
 424
 425         case FLUSH_CACHE:
 426                 __flush_cache_all();
 427                 return 0;
 428         }
 429
 430         return -EINVAL;
 431 }
 432
 433 /*
 434  * sys_ipc() is the de-multiplexer for the SysV IPC calls..
 435  *
 436  * This is really horribly ugly.
 437  */
 438 SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, int, second,
 439         unsigned long, third, void __user *, ptr, long, fifth)
 440 {
 441         int version, ret;
 442
 443         version = call >> 16; /* hack for backward compatibility */
 444         call &= 0xffff;
 445
 446         switch (call) {
 447         case SEMOP:
 448                 return sys_semtimedop(first, (struct sembuf __user *)ptr,
 449                                       second, NULL);
 450         case SEMTIMEDOP:
 451                 return sys_semtimedop(first, (struct sembuf __user *)ptr,
 452                                       second,
 453                                       (const struct timespec __user *)fifth);
 454         case SEMGET:
 455                 return sys_semget(first, second, third);
 456         case SEMCTL: {
 457                 union semun fourth;
 458                 if (!ptr)
 459                         return -EINVAL;
 460                 if (get_user(fourth.__pad, (void __user *__user *) ptr))
 461                         return -EFAULT;
 462                 return sys_semctl(first, second, third, fourth);
 463         }
 464
 465         case MSGSND:
 466                 return sys_msgsnd(first, (struct msgbuf __user *) ptr,
 467                                   second, third);
 468         case MSGRCV:
 469                 switch (version) {
 470                 case 0: {
 471                         struct ipc_kludge tmp;
 472                         if (!ptr)
 473                                 return -EINVAL;
 474
 475                         if (copy_from_user(&tmp,
 476                                            (struct ipc_kludge __user *) ptr,
 477                                            sizeof(tmp)))
 478                                 return -EFAULT;
 479                         return sys_msgrcv(first, tmp.msgp, second,
 480                                           tmp.msgtyp, third);
 481                 }
 482                 default:
 483                         return sys_msgrcv(first,
 484                                           (struct msgbuf __user *) ptr,
 485                                           second, fifth, third);
 486                 }
 487         case MSGGET:
 488                 return sys_msgget((key_t) first, second);
 489         case MSGCTL:
 490                 return sys_msgctl(first, second,
 491                                   (struct msqid_ds __user *) ptr);
 492
 493         case SHMAT:
 494                 switch (version) {
 495                 default: {
 496                         unsigned long raddr;
 497                         ret = do_shmat(first, (char __user *) ptr, second,
 498                                        &raddr);
 499                         if (ret)
 500                                 return ret;
 501                         return put_user(raddr, (unsigned long __user *) third);
 502                 }
 503                 case 1: /* iBCS2 emulator entry point */
 504                         if (!segment_eq(get_fs(), get_ds()))
 505                                 return -EINVAL;
 506                         return do_shmat(first, (char __user *) ptr, second,
 507                                         (unsigned long *) third);
 508                 }
 509         case SHMDT:
 510                 return sys_shmdt((char __user *)ptr);
 511         case SHMGET:
 512                 return sys_shmget(first, second, third);
 513         case SHMCTL:
 514                 return sys_shmctl(first, second,
 515                                   (struct shmid_ds __user *) ptr);
 516         default:
 517                 return -ENOSYS;
 518         }
 519 }
 520
 521 /*
 522  * No implemented yet ...
 523  */
 524 SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
 525 {
 526         return -ENOSYS;
 527 }
 528
 529 /*
 530  * If we ever come here the user sp is bad.  Zap the process right away.
 531  * Due to the bad stack signaling wouldn't work.
 532  */
 533 asmlinkage void bad_stack(void)
 534 {
 535         do_exit(SIGSEGV);
 536 }
 537
 538 /*
 539  * Do a system call from kernel instead of calling sys_execve so we
 540  * end up with proper pt_regs.
 541  */
 542 int kernel_execve(const char *filename, char *const argv[], char *const envp[])
 543 {
 544         register unsigned long __a0 asm("$4") = (unsigned long) filename;
 545         register unsigned long __a1 asm("$5") = (unsigned long) argv;
 546         register unsigned long __a2 asm("$6") = (unsigned long) envp;
 547         register unsigned long __a3 asm("$7");
 548         unsigned long __v0;
 549
 550         __asm__ volatile ("                                     \n"
 551         "       .set    noreorder                               \n"
 552         "       li      $2, %5          # __NR_execve           \n"
 553         "       syscall                                         \n"
 554         "       move    %0, $2                                  \n"
 555         "       .set    reorder                                 \n"
 556         : "=&r" (__v0), "=r" (__a3)
 557         : "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_execve)
 558         : "$2", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24",
 559           "memory");
 560
 561         if (__a3 == 0)
 562                 return __v0;
 563
 564         return -__v0;
 565 }