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
  83         if (len > TASK_SIZE)
  84                 return -ENOMEM;
  85
  86         if (flags & MAP_FIXED) {
  87                 /* Even MAP_FIXED mappings must reside within TASK_SIZE.  */
  88                 if (TASK_SIZE - len < addr)
  89                         return -EINVAL;
  90
  91                 /*
  92                  * We do not accept a shared mapping if it would violate
  93                  * cache aliasing constraints.
  94                  */
  95                 if ((flags & MAP_SHARED) &&
  96                     ((addr - (pgoff << PAGE_SHIFT)) & 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 = current->mm->mmap_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 void arch_pick_mmap_layout(struct mm_struct *mm)
 133 {
 134         unsigned long random_factor = 0UL;
 135
 136         if (current->flags & PF_RANDOMIZE) {
 137                 random_factor = get_random_int();
 138                 random_factor = random_factor << PAGE_SHIFT;
 139                 if (TASK_IS_32BIT_ADDR)
 140                         random_factor &= 0xfffffful;
 141                 else
 142                         random_factor &= 0xffffffful;
 143         }
 144
 145         mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
 146         mm->get_unmapped_area = arch_get_unmapped_area;
 147         mm->unmap_area = arch_unmap_area;
 148 }
 149
 150 static inline unsigned long brk_rnd(void)
 151 {
 152         unsigned long rnd = get_random_int();
 153
 154         rnd = rnd << PAGE_SHIFT;
 155         /* 8MB for 32bit, 256MB for 64bit */
 156         if (TASK_IS_32BIT_ADDR)
 157                 rnd = rnd & 0x7ffffful;
 158         else
 159                 rnd = rnd & 0xffffffful;
 160
 161         return rnd;
 162 }
 163
 164 unsigned long arch_randomize_brk(struct mm_struct *mm)
 165 {
 166         unsigned long base = mm->brk;
 167         unsigned long ret;
 168
 169         ret = PAGE_ALIGN(base + brk_rnd());
 170
 171         if (ret < mm->brk)
 172                 return mm->brk;
 173
 174         return ret;
 175 }
 176
 177 SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
 178         unsigned long, prot, unsigned long, flags, unsigned long,
 179         fd, off_t, offset)
 180 {
 181         unsigned long result;
 182
 183         result = -EINVAL;
 184         if (offset & ~PAGE_MASK)
 185                 goto out;
 186
 187         result = sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
 188
 189 out:
 190         return result;
 191 }
 192
 193 SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
 194         unsigned long, prot, unsigned long, flags, unsigned long, fd,
 195         unsigned long, pgoff)
 196 {
 197         if (pgoff & (~PAGE_MASK >> 12))
 198                 return -EINVAL;
 199
 200         return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
 201 }
 202
 203 save_static_function(sys_fork);
 204 static int __used noinline
 205 _sys_fork(nabi_no_regargs struct pt_regs regs)
 206 {
 207         return do_fork(SIGCHLD, regs.regs[29], &regs, 0, NULL, NULL);
 208 }
 209
 210 save_static_function(sys_clone);
 211 static int __used noinline
 212 _sys_clone(nabi_no_regargs struct pt_regs regs)
 213 {
 214         unsigned long clone_flags;
 215         unsigned long newsp;
 216         int __user *parent_tidptr, *child_tidptr;
 217
 218         clone_flags = regs.regs[4];
 219         newsp = regs.regs[5];
 220         if (!newsp)
 221                 newsp = regs.regs[29];
 222         parent_tidptr = (int __user *) regs.regs[6];
 223 #ifdef CONFIG_32BIT
 224         /* We need to fetch the fifth argument off the stack.  */
 225         child_tidptr = NULL;
 226         if (clone_flags & (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)) {
 227                 int __user *__user *usp = (int __user *__user *) regs.regs[29];
 228                 if (regs.regs[2] == __NR_syscall) {
 229                         if (get_user (child_tidptr, &usp[5]))
 230                                 return -EFAULT;
 231                 }
 232                 else if (get_user (child_tidptr, &usp[4]))
 233                         return -EFAULT;
 234         }
 235 #else
 236         child_tidptr = (int __user *) regs.regs[8];
 237 #endif
 238         return do_fork(clone_flags, newsp, &regs, 0,
 239                        parent_tidptr, child_tidptr);
 240 }
 241
 242 /*
 243  * sys_execve() executes a new program.
 244  */
 245 asmlinkage int sys_execve(nabi_no_regargs struct pt_regs regs)
 246 {
 247         int error;
 248         char * filename;
 249
 250         filename = getname((const char __user *) (long)regs.regs[4]);
 251         error = PTR_ERR(filename);
 252         if (IS_ERR(filename))
 253                 goto out;
 254         error = do_execve(filename,
 255                           (const char __user *const __user *) (long)regs.regs[5],
 256                           (const char __user *const __user *) (long)regs.regs[6],
 257                           &regs);
 258         putname(filename);
 259
 260 out:
 261         return error;
 262 }
 263
 264 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
 265 {
 266         struct thread_info *ti = task_thread_info(current);
 267
 268         ti->tp_value = addr;
 269         if (cpu_has_userlocal)
 270                 write_c0_userlocal(addr);
 271
 272         return 0;
 273 }
 274
 275 static inline int mips_atomic_set(struct pt_regs *regs,
 276         unsigned long addr, unsigned long new)
 277 {
 278         unsigned long old, tmp;
 279         unsigned int err;
 280
 281         if (unlikely(addr & 3))
 282                 return -EINVAL;
 283
 284         if (unlikely(!access_ok(VERIFY_WRITE, addr, 4)))
 285                 return -EINVAL;
 286
 287         if (cpu_has_llsc && R10000_LLSC_WAR) {
 288                 __asm__ __volatile__ (
 289                 "       .set    mips3                                   \n"
 290                 "       li      %[err], 0                               \n"
 291                 "1:     ll      %[old], (%[addr])                       \n"
 292                 "       move    %[tmp], %[new]                          \n"
 293                 "2:     sc      %[tmp], (%[addr])                       \n"
 294                 "       beqzl   %[tmp], 1b                              \n"
 295                 "3:                                                     \n"
 296                 "       .section .fixup,\"ax\"                          \n"
 297                 "4:     li      %[err], %[efault]                       \n"
 298                 "       j       3b                                      \n"
 299                 "       .previous                                       \n"
 300                 "       .section __ex_table,\"a\"                       \n"
 301                 "       "STR(PTR)"      1b, 4b                          \n"
 302                 "       "STR(PTR)"      2b, 4b                          \n"
 303                 "       .previous                                       \n"
 304                 "       .set    mips0                                   \n"
 305                 : [old] "=&r" (old),
 306                   [err] "=&r" (err),
 307                   [tmp] "=&r" (tmp)
 308                 : [addr] "r" (addr),
 309                   [new] "r" (new),
 310                   [efault] "i" (-EFAULT)
 311                 : "memory");
 312         } else if (cpu_has_llsc) {
 313                 __asm__ __volatile__ (
 314                 "       .set    mips3                                   \n"
 315                 "       li      %[err], 0                               \n"
 316                 "1:     ll      %[old], (%[addr])                       \n"
 317                 "       move    %[tmp], %[new]                          \n"
 318                 "2:     sc      %[tmp], (%[addr])                       \n"
 319                 "       bnez    %[tmp], 4f                              \n"
 320                 "3:                                                     \n"
 321                 "       .subsection 2                                   \n"
 322                 "4:     b       1b                                      \n"
 323                 "       .previous                                       \n"
 324                 "                                                       \n"
 325                 "       .section .fixup,\"ax\"                          \n"
 326                 "5:     li      %[err], %[efault]                       \n"
 327                 "       j       3b                                      \n"
 328                 "       .previous                                       \n"
 329                 "       .section __ex_table,\"a\"                       \n"
 330                 "       "STR(PTR)"      1b, 5b                          \n"
 331                 "       "STR(PTR)"      2b, 5b                          \n"
 332                 "       .previous                                       \n"
 333                 "       .set    mips0                                   \n"
 334                 : [old] "=&r" (old),
 335                   [err] "=&r" (err),
 336                   [tmp] "=&r" (tmp)
 337                 : [addr] "r" (addr),
 338                   [new] "r" (new),
 339                   [efault] "i" (-EFAULT)
 340                 : "memory");
 341         } else {
 342                 do {
 343                         preempt_disable();
 344                         ll_bit = 1;
 345                         ll_task = current;
 346                         preempt_enable();
 347
 348                         err = __get_user(old, (unsigned int *) addr);
 349                         err |= __put_user(new, (unsigned int *) addr);
 350                         if (err)
 351                                 break;
 352                         rmb();
 353                 } while (!ll_bit);
 354         }
 355
 356         if (unlikely(err))
 357                 return err;
 358
 359         regs->regs[2] = old;
 360         regs->regs[7] = 0;      /* No error */
 361
 362         /*
 363          * Don't let your children do this ...
 364          */
 365         __asm__ __volatile__(
 366         "       move    $29, %0                                         \n"
 367         "       j       syscall_exit                                    \n"
 368         : /* no outputs */
 369         : "r" (regs));
 370
 371         /* unreached.  Honestly.  */
 372         while (1);
 373 }
 374
 375 save_static_function(sys_sysmips);
 376 static int __used noinline
 377 _sys_sysmips(nabi_no_regargs struct pt_regs regs)
 378 {
 379         long cmd, arg1, arg2;
 380
 381         cmd = regs.regs[4];
 382         arg1 = regs.regs[5];
 383         arg2 = regs.regs[6];
 384
 385         switch (cmd) {
 386         case MIPS_ATOMIC_SET:
 387                 return mips_atomic_set(&regs, arg1, arg2);
 388
 389         case MIPS_FIXADE:
 390                 if (arg1 & ~3)
 391                         return -EINVAL;
 392
 393                 if (arg1 & 1)
 394                         set_thread_flag(TIF_FIXADE);
 395                 else
 396                         clear_thread_flag(TIF_FIXADE);
 397                 if (arg1 & 2)
 398                         set_thread_flag(TIF_LOGADE);
 399                 else
 400                         clear_thread_flag(TIF_LOGADE);
 401
 402                 return 0;
 403
 404         case FLUSH_CACHE:
 405                 __flush_cache_all();
 406                 return 0;
 407         }
 408
 409         return -EINVAL;
 410 }
 411
 412 /*
 413  * No implemented yet ...
 414  */
 415 SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
 416 {
 417         return -ENOSYS;
 418 }
 419
 420 /*
 421  * If we ever come here the user sp is bad.  Zap the process right away.
 422  * Due to the bad stack signaling wouldn't work.
 423  */
 424 asmlinkage void bad_stack(void)
 425 {
 426         do_exit(SIGSEGV);
 427 }
 428
 429 /*
 430  * Do a system call from kernel instead of calling sys_execve so we
 431  * end up with proper pt_regs.
 432  */
 433 int kernel_execve(const char *filename,
 434                   const char *const argv[],
 435                   const char *const envp[])
 436 {
 437         register unsigned long __a0 asm("$4") = (unsigned long) filename;
 438         register unsigned long __a1 asm("$5") = (unsigned long) argv;
 439         register unsigned long __a2 asm("$6") = (unsigned long) envp;
 440         register unsigned long __a3 asm("$7");
 441         unsigned long __v0;
 442
 443         __asm__ volatile ("                                     \n"
 444         "       .set    noreorder                               \n"
 445         "       li      $2, %5          # __NR_execve           \n"
 446         "       syscall                                         \n"
 447         "       move    %0, $2                                  \n"
 448         "       .set    reorder                                 \n"
 449         : "=&r" (__v0), "=r" (__a3)
 450         : "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_execve)
 451         : "$2", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24",
 452           "memory");
 453
 454         if (__a3 == 0)
 455                 return __v0;
 456
 457         return -__v0;
 458 }