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/utsname.h>
  23 #include <linux/unistd.h>
  24 #include <linux/sem.h>
  25 #include <linux/msg.h>
  26 #include <linux/shm.h>
  27 #include <linux/compiler.h>
  28 #include <linux/module.h>
  29 #include <linux/ipc.h>
  30 #include <linux/uaccess.h>
  31 #include <linux/slab.h>
  32 #include <linux/random.h>
  33 #include <linux/elf.h>
  34
  35 #include <asm/asm.h>
  36 #include <asm/branch.h>
  37 #include <asm/cachectl.h>
  38 #include <asm/cacheflush.h>
  39 #include <asm/asm-offsets.h>
  40 #include <asm/signal.h>
  41 #include <asm/sim.h>
  42 #include <asm/shmparam.h>
  43 #include <asm/sysmips.h>
  44 #include <asm/uaccess.h>
  45
  46 /*
  47  * For historic reasons the pipe(2) syscall on MIPS has an unusual calling
  48  * convention.  It returns results in registers $v0 / $v1 which means there
  49  * is no need for it to do verify the validity of a userspace pointer
  50  * argument.  Historically that used to be expensive in Linux.  These days
  51  * the performance advantage is negligible.
  52  */
  53 asmlinkage int sysm_pipe(nabi_no_regargs volatile struct pt_regs regs)
  54 {
  55         int fd[2];
  56         int error, res;
  57
  58         error = do_pipe_flags(fd, 0);
  59         if (error) {
  60                 res = error;
  61                 goto out;
  62         }
  63         regs.regs[3] = fd[1];
  64         res = fd[0];
  65 out:
  66         return res;
  67 }
  68
  69 unsigned long shm_align_mask = PAGE_SIZE - 1;   /* Sane caches */
  70
  71 EXPORT_SYMBOL(shm_align_mask);
  72
  73 #define COLOUR_ALIGN(addr,pgoff)                                \
  74         ((((addr) + shm_align_mask) & ~shm_align_mask) +        \
  75          (((pgoff) << PAGE_SHIFT) & shm_align_mask))
  76
  77 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
  78         unsigned long len, unsigned long pgoff, unsigned long flags)
  79 {
  80         struct vm_area_struct * vmm;
  81         int do_color_align;
  82         unsigned long task_size;
  83
  84 #ifdef CONFIG_32BIT
  85         task_size = TASK_SIZE;
  86 #else /* Must be CONFIG_64BIT*/
  87         task_size = test_thread_flag(TIF_32BIT_ADDR) ? TASK_SIZE32 : TASK_SIZE;
  88 #endif
  89
  90         if (len > task_size)
  91                 return -ENOMEM;
  92
  93         if (flags & MAP_FIXED) {
  94                 /* Even MAP_FIXED mappings must reside within task_size.  */
  95                 if (task_size - len < addr)
  96                         return -EINVAL;
  97
  98                 /*
  99                  * We do not accept a shared mapping if it would violate
 100                  * cache aliasing constraints.
 101                  */
 102                 if ((flags & MAP_SHARED) &&
 103                     ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
 104                         return -EINVAL;
 105                 return addr;
 106         }
 107
 108         do_color_align = 0;
 109         if (filp || (flags & MAP_SHARED))
 110                 do_color_align = 1;
 111         if (addr) {
 112                 if (do_color_align)
 113                         addr = COLOUR_ALIGN(addr, pgoff);
 114                 else
 115                         addr = PAGE_ALIGN(addr);
 116                 vmm = find_vma(current->mm, addr);
 117                 if (task_size - len >= addr &&
 118                     (!vmm || addr + len <= vmm->vm_start))
 119                         return addr;
 120         }
 121         addr = current->mm->mmap_base;
 122         if (do_color_align)
 123                 addr = COLOUR_ALIGN(addr, pgoff);
 124         else
 125                 addr = PAGE_ALIGN(addr);
 126
 127         for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
 128                 /* At this point:  (!vmm || addr < vmm->vm_end). */
 129                 if (task_size - len < addr)
 130                         return -ENOMEM;
 131                 if (!vmm || addr + len <= vmm->vm_start)
 132                         return addr;
 133                 addr = vmm->vm_end;
 134                 if (do_color_align)
 135                         addr = COLOUR_ALIGN(addr, pgoff);
 136         }
 137 }
 138
 139 void arch_pick_mmap_layout(struct mm_struct *mm)
 140 {
 141         unsigned long random_factor = 0UL;
 142
 143         if (current->flags & PF_RANDOMIZE) {
 144                 random_factor = get_random_int();
 145                 random_factor = random_factor << PAGE_SHIFT;
 146                 if (TASK_IS_32BIT_ADDR)
 147                         random_factor &= 0xfffffful;
 148                 else
 149                         random_factor &= 0xffffffful;
 150         }
 151
 152         mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
 153         mm->get_unmapped_area = arch_get_unmapped_area;
 154         mm->unmap_area = arch_unmap_area;
 155 }
 156
 157 static inline unsigned long brk_rnd(void)
 158 {
 159         unsigned long rnd = get_random_int();
 160
 161         rnd = rnd << PAGE_SHIFT;
 162         /* 8MB for 32bit, 256MB for 64bit */
 163         if (TASK_IS_32BIT_ADDR)
 164                 rnd = rnd & 0x7ffffful;
 165         else
 166                 rnd = rnd & 0xffffffful;
 167
 168         return rnd;
 169 }
 170
 171 unsigned long arch_randomize_brk(struct mm_struct *mm)
 172 {
 173         unsigned long base = mm->brk;
 174         unsigned long ret;
 175
 176         ret = PAGE_ALIGN(base + brk_rnd());
 177
 178         if (ret < mm->brk)
 179                 return mm->brk;
 180
 181         return ret;
 182 }
 183
 184 SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
 185         unsigned long, prot, unsigned long, flags, unsigned long,
 186         fd, off_t, offset)
 187 {
 188         unsigned long result;
 189
 190         result = -EINVAL;
 191         if (offset & ~PAGE_MASK)
 192                 goto out;
 193
 194         result = sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
 195
 196 out:
 197         return result;
 198 }
 199
 200 SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
 201         unsigned long, prot, unsigned long, flags, unsigned long, fd,
 202         unsigned long, pgoff)
 203 {
 204         if (pgoff & (~PAGE_MASK >> 12))
 205                 return -EINVAL;
 206
 207         return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
 208 }
 209
 210 save_static_function(sys_fork);
 211 static int __used noinline
 212 _sys_fork(nabi_no_regargs struct pt_regs regs)
 213 {
 214         return do_fork(SIGCHLD, regs.regs[29], &regs, 0, NULL, NULL);
 215 }
 216
 217 save_static_function(sys_clone);
 218 static int __used noinline
 219 _sys_clone(nabi_no_regargs struct pt_regs regs)
 220 {
 221         unsigned long clone_flags;
 222         unsigned long newsp;
 223         int __user *parent_tidptr, *child_tidptr;
 224
 225         clone_flags = regs.regs[4];
 226         newsp = regs.regs[5];
 227         if (!newsp)
 228                 newsp = regs.regs[29];
 229         parent_tidptr = (int __user *) regs.regs[6];
 230 #ifdef CONFIG_32BIT
 231         /* We need to fetch the fifth argument off the stack.  */
 232         child_tidptr = NULL;
 233         if (clone_flags & (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)) {
 234                 int __user *__user *usp = (int __user *__user *) regs.regs[29];
 235                 if (regs.regs[2] == __NR_syscall) {
 236                         if (get_user (child_tidptr, &usp[5]))
 237                                 return -EFAULT;
 238                 }
 239                 else if (get_user (child_tidptr, &usp[4]))
 240                         return -EFAULT;
 241         }
 242 #else
 243         child_tidptr = (int __user *) regs.regs[8];
 244 #endif
 245         return do_fork(clone_flags, newsp, &regs, 0,
 246                        parent_tidptr, child_tidptr);
 247 }
 248
 249 /*
 250  * sys_execve() executes a new program.
 251  */
 252 asmlinkage int sys_execve(nabi_no_regargs struct pt_regs regs)
 253 {
 254         int error;
 255         char * filename;
 256
 257         filename = getname((const char __user *) (long)regs.regs[4]);
 258         error = PTR_ERR(filename);
 259         if (IS_ERR(filename))
 260                 goto out;
 261         error = do_execve(filename,
 262                           (const char __user *const __user *) (long)regs.regs[5],
 263                           (const char __user *const __user *) (long)regs.regs[6],
 264                           &regs);
 265         putname(filename);
 266
 267 out:
 268         return error;
 269 }
 270
 271 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
 272 {
 273         struct thread_info *ti = task_thread_info(current);
 274
 275         ti->tp_value = addr;
 276         if (cpu_has_userlocal)
 277                 write_c0_userlocal(addr);
 278
 279         return 0;
 280 }
 281
 282 static inline int mips_atomic_set(struct pt_regs *regs,
 283         unsigned long addr, unsigned long new)
 284 {
 285         unsigned long old, tmp;
 286         unsigned int err;
 287
 288         if (unlikely(addr & 3))
 289                 return -EINVAL;
 290
 291         if (unlikely(!access_ok(VERIFY_WRITE, addr, 4)))
 292                 return -EINVAL;
 293
 294         if (cpu_has_llsc && R10000_LLSC_WAR) {
 295                 __asm__ __volatile__ (
 296                 "       .set    mips3                                   \n"
 297                 "       li      %[err], 0                               \n"
 298                 "1:     ll      %[old], (%[addr])                       \n"
 299                 "       move    %[tmp], %[new]                          \n"
 300                 "2:     sc      %[tmp], (%[addr])                       \n"
 301                 "       beqzl   %[tmp], 1b                              \n"
 302                 "3:                                                     \n"
 303                 "       .section .fixup,\"ax\"                          \n"
 304                 "4:     li      %[err], %[efault]                       \n"
 305                 "       j       3b                                      \n"
 306                 "       .previous                                       \n"
 307                 "       .section __ex_table,\"a\"                       \n"
 308                 "       "STR(PTR)"      1b, 4b                          \n"
 309                 "       "STR(PTR)"      2b, 4b                          \n"
 310                 "       .previous                                       \n"
 311                 "       .set    mips0                                   \n"
 312                 : [old] "=&r" (old),
 313                   [err] "=&r" (err),
 314                   [tmp] "=&r" (tmp)
 315                 : [addr] "r" (addr),
 316                   [new] "r" (new),
 317                   [efault] "i" (-EFAULT)
 318                 : "memory");
 319         } else if (cpu_has_llsc) {
 320                 __asm__ __volatile__ (
 321                 "       .set    mips3                                   \n"
 322                 "       li      %[err], 0                               \n"
 323                 "1:     ll      %[old], (%[addr])                       \n"
 324                 "       move    %[tmp], %[new]                          \n"
 325                 "2:     sc      %[tmp], (%[addr])                       \n"
 326                 "       bnez    %[tmp], 4f                              \n"
 327                 "3:                                                     \n"
 328                 "       .subsection 2                                   \n"
 329                 "4:     b       1b                                      \n"
 330                 "       .previous                                       \n"
 331                 "                                                       \n"
 332                 "       .section .fixup,\"ax\"                          \n"
 333                 "5:     li      %[err], %[efault]                       \n"
 334                 "       j       3b                                      \n"
 335                 "       .previous                                       \n"
 336                 "       .section __ex_table,\"a\"                       \n"
 337                 "       "STR(PTR)"      1b, 5b                          \n"
 338                 "       "STR(PTR)"      2b, 5b                          \n"
 339                 "       .previous                                       \n"
 340                 "       .set    mips0                                   \n"
 341                 : [old] "=&r" (old),
 342                   [err] "=&r" (err),
 343                   [tmp] "=&r" (tmp)
 344                 : [addr] "r" (addr),
 345                   [new] "r" (new),
 346                   [efault] "i" (-EFAULT)
 347                 : "memory");
 348         } else {
 349                 do {
 350                         preempt_disable();
 351                         ll_bit = 1;
 352                         ll_task = current;
 353                         preempt_enable();
 354
 355                         err = __get_user(old, (unsigned int *) addr);
 356                         err |= __put_user(new, (unsigned int *) addr);
 357                         if (err)
 358                                 break;
 359                         rmb();
 360                 } while (!ll_bit);
 361         }
 362
 363         if (unlikely(err))
 364                 return err;
 365
 366         regs->regs[2] = old;
 367         regs->regs[7] = 0;      /* No error */
 368
 369         /*
 370          * Don't let your children do this ...
 371          */
 372         __asm__ __volatile__(
 373         "       move    $29, %0                                         \n"
 374         "       j       syscall_exit                                    \n"
 375         : /* no outputs */
 376         : "r" (regs));
 377
 378         /* unreached.  Honestly.  */
 379         while (1);
 380 }
 381
 382 save_static_function(sys_sysmips);
 383 static int __used noinline
 384 _sys_sysmips(nabi_no_regargs struct pt_regs regs)
 385 {
 386         long cmd, arg1, arg2;
 387
 388         cmd = regs.regs[4];
 389         arg1 = regs.regs[5];
 390         arg2 = regs.regs[6];
 391
 392         switch (cmd) {
 393         case MIPS_ATOMIC_SET:
 394                 return mips_atomic_set(&regs, arg1, arg2);
 395
 396         case MIPS_FIXADE:
 397                 if (arg1 & ~3)
 398                         return -EINVAL;
 399
 400                 if (arg1 & 1)
 401                         set_thread_flag(TIF_FIXADE);
 402                 else
 403                         clear_thread_flag(TIF_FIXADE);
 404                 if (arg1 & 2)
 405                         set_thread_flag(TIF_LOGADE);
 406                 else
 407                         clear_thread_flag(TIF_LOGADE);
 408
 409                 return 0;
 410
 411         case FLUSH_CACHE:
 412                 __flush_cache_all();
 413                 return 0;
 414         }
 415
 416         return -EINVAL;
 417 }
 418
 419 /*
 420  * No implemented yet ...
 421  */
 422 SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
 423 {
 424         return -ENOSYS;
 425 }
 426
 427 /*
 428  * If we ever come here the user sp is bad.  Zap the process right away.
 429  * Due to the bad stack signaling wouldn't work.
 430  */
 431 asmlinkage void bad_stack(void)
 432 {
 433         do_exit(SIGSEGV);
 434 }
 435
 436 /*
 437  * Do a system call from kernel instead of calling sys_execve so we
 438  * end up with proper pt_regs.
 439  */
 440 int kernel_execve(const char *filename,
 441                   const char *const argv[],
 442                   const char *const envp[])
 443 {
 444         register unsigned long __a0 asm("$4") = (unsigned long) filename;
 445         register unsigned long __a1 asm("$5") = (unsigned long) argv;
 446         register unsigned long __a2 asm("$6") = (unsigned long) envp;
 447         register unsigned long __a3 asm("$7");
 448         unsigned long __v0;
 449
 450         __asm__ volatile ("                                     \n"
 451         "       .set    noreorder                               \n"
 452         "       li      $2, %5          # __NR_execve           \n"
 453         "       syscall                                         \n"
 454         "       move    %0, $2                                  \n"
 455         "       .set    reorder                                 \n"
 456         : "=&r" (__v0), "=r" (__a3)
 457         : "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_execve)
 458         : "$2", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24",
 459           "memory");
 460
 461         if (__a3 == 0)
 462                 return __v0;
 463
 464         return -__v0;
 465 }