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
  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 #ifdef CONFIG_32BIT
  83         task_size = TASK_SIZE;
  84 #else /* Must be CONFIG_64BIT*/
  85         task_size = test_thread_flag(TIF_32BIT_ADDR) ? TASK_SIZE32 : TASK_SIZE;
  86 #endif
  87
  88         if (len > task_size)
  89                 return -ENOMEM;
  90
  91         if (flags & MAP_FIXED) {
  92                 /* Even MAP_FIXED mappings must reside within task_size.  */
  93                 if (task_size - len < addr)
  94                         return -EINVAL;
  95
  96                 /*
  97                  * We do not accept a shared mapping if it would violate
  98                  * cache aliasing constraints.
  99                  */
 100                 if ((flags & MAP_SHARED) &&
 101                     ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
 102                         return -EINVAL;
 103                 return addr;
 104         }
 105
 106         do_color_align = 0;
 107         if (filp || (flags & MAP_SHARED))
 108                 do_color_align = 1;
 109         if (addr) {
 110                 if (do_color_align)
 111                         addr = COLOUR_ALIGN(addr, pgoff);
 112                 else
 113                         addr = PAGE_ALIGN(addr);
 114                 vmm = find_vma(current->mm, addr);
 115                 if (task_size - len >= addr &&
 116                     (!vmm || addr + len <= vmm->vm_start))
 117                         return addr;
 118         }
 119         addr = TASK_UNMAPPED_BASE;
 120         if (do_color_align)
 121                 addr = COLOUR_ALIGN(addr, pgoff);
 122         else
 123                 addr = PAGE_ALIGN(addr);
 124
 125         for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
 126                 /* At this point:  (!vmm || addr < vmm->vm_end). */
 127                 if (task_size - len < addr)
 128                         return -ENOMEM;
 129                 if (!vmm || addr + len <= vmm->vm_start)
 130                         return addr;
 131                 addr = vmm->vm_end;
 132                 if (do_color_align)
 133                         addr = COLOUR_ALIGN(addr, pgoff);
 134         }
 135 }
 136
 137 SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
 138         unsigned long, prot, unsigned long, flags, unsigned long,
 139         fd, off_t, offset)
 140 {
 141         unsigned long result;
 142
 143         result = -EINVAL;
 144         if (offset & ~PAGE_MASK)
 145                 goto out;
 146
 147         result = sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
 148
 149 out:
 150         return result;
 151 }
 152
 153 SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
 154         unsigned long, prot, unsigned long, flags, unsigned long, fd,
 155         unsigned long, pgoff)
 156 {
 157         if (pgoff & (~PAGE_MASK >> 12))
 158                 return -EINVAL;
 159
 160         return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
 161 }
 162
 163 save_static_function(sys_fork);
 164 static int __used noinline
 165 _sys_fork(nabi_no_regargs struct pt_regs regs)
 166 {
 167         return do_fork(SIGCHLD, regs.regs[29], &regs, 0, NULL, NULL);
 168 }
 169
 170 save_static_function(sys_clone);
 171 static int __used noinline
 172 _sys_clone(nabi_no_regargs struct pt_regs regs)
 173 {
 174         unsigned long clone_flags;
 175         unsigned long newsp;
 176         int __user *parent_tidptr, *child_tidptr;
 177
 178         clone_flags = regs.regs[4];
 179         newsp = regs.regs[5];
 180         if (!newsp)
 181                 newsp = regs.regs[29];
 182         parent_tidptr = (int __user *) regs.regs[6];
 183 #ifdef CONFIG_32BIT
 184         /* We need to fetch the fifth argument off the stack.  */
 185         child_tidptr = NULL;
 186         if (clone_flags & (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)) {
 187                 int __user *__user *usp = (int __user *__user *) regs.regs[29];
 188                 if (regs.regs[2] == __NR_syscall) {
 189                         if (get_user (child_tidptr, &usp[5]))
 190                                 return -EFAULT;
 191                 }
 192                 else if (get_user (child_tidptr, &usp[4]))
 193                         return -EFAULT;
 194         }
 195 #else
 196         child_tidptr = (int __user *) regs.regs[8];
 197 #endif
 198         return do_fork(clone_flags, newsp, &regs, 0,
 199                        parent_tidptr, child_tidptr);
 200 }
 201
 202 /*
 203  * sys_execve() executes a new program.
 204  */
 205 asmlinkage int sys_execve(nabi_no_regargs struct pt_regs regs)
 206 {
 207         int error;
 208         char * filename;
 209
 210         filename = getname((char __user *) (long)regs.regs[4]);
 211         error = PTR_ERR(filename);
 212         if (IS_ERR(filename))
 213                 goto out;
 214         error = do_execve(filename, (char __user *__user *) (long)regs.regs[5],
 215                           (char __user *__user *) (long)regs.regs[6], &regs);
 216         putname(filename);
 217
 218 out:
 219         return error;
 220 }
 221
 222 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
 223 {
 224         struct thread_info *ti = task_thread_info(current);
 225
 226         ti->tp_value = addr;
 227         if (cpu_has_userlocal)
 228                 write_c0_userlocal(addr);
 229
 230         return 0;
 231 }
 232
 233 static inline int mips_atomic_set(struct pt_regs *regs,
 234         unsigned long addr, unsigned long new)
 235 {
 236         unsigned long old, tmp;
 237         unsigned int err;
 238
 239         if (unlikely(addr & 3))
 240                 return -EINVAL;
 241
 242         if (unlikely(!access_ok(VERIFY_WRITE, addr, 4)))
 243                 return -EINVAL;
 244
 245         if (cpu_has_llsc && R10000_LLSC_WAR) {
 246                 __asm__ __volatile__ (
 247                 "       .set    mips3                                   \n"
 248                 "       li      %[err], 0                               \n"
 249                 "1:     ll      %[old], (%[addr])                       \n"
 250                 "       move    %[tmp], %[new]                          \n"
 251                 "2:     sc      %[tmp], (%[addr])                       \n"
 252                 "       beqzl   %[tmp], 1b                              \n"
 253                 "3:                                                     \n"
 254                 "       .section .fixup,\"ax\"                          \n"
 255                 "4:     li      %[err], %[efault]                       \n"
 256                 "       j       3b                                      \n"
 257                 "       .previous                                       \n"
 258                 "       .section __ex_table,\"a\"                       \n"
 259                 "       "STR(PTR)"      1b, 4b                          \n"
 260                 "       "STR(PTR)"      2b, 4b                          \n"
 261                 "       .previous                                       \n"
 262                 "       .set    mips0                                   \n"
 263                 : [old] "=&r" (old),
 264                   [err] "=&r" (err),
 265                   [tmp] "=&r" (tmp)
 266                 : [addr] "r" (addr),
 267                   [new] "r" (new),
 268                   [efault] "i" (-EFAULT)
 269                 : "memory");
 270         } else if (cpu_has_llsc) {
 271                 __asm__ __volatile__ (
 272                 "       .set    mips3                                   \n"
 273                 "       li      %[err], 0                               \n"
 274                 "1:     ll      %[old], (%[addr])                       \n"
 275                 "       move    %[tmp], %[new]                          \n"
 276                 "2:     sc      %[tmp], (%[addr])                       \n"
 277                 "       bnez    %[tmp], 4f                              \n"
 278                 "3:                                                     \n"
 279                 "       .subsection 2                                   \n"
 280                 "4:     b       1b                                      \n"
 281                 "       .previous                                       \n"
 282                 "                                                       \n"
 283                 "       .section .fixup,\"ax\"                          \n"
 284                 "5:     li      %[err], %[efault]                       \n"
 285                 "       j       3b                                      \n"
 286                 "       .previous                                       \n"
 287                 "       .section __ex_table,\"a\"                       \n"
 288                 "       "STR(PTR)"      1b, 5b                          \n"
 289                 "       "STR(PTR)"      2b, 5b                          \n"
 290                 "       .previous                                       \n"
 291                 "       .set    mips0                                   \n"
 292                 : [old] "=&r" (old),
 293                   [err] "=&r" (err),
 294                   [tmp] "=&r" (tmp)
 295                 : [addr] "r" (addr),
 296                   [new] "r" (new),
 297                   [efault] "i" (-EFAULT)
 298                 : "memory");
 299         } else {
 300                 do {
 301                         preempt_disable();
 302                         ll_bit = 1;
 303                         ll_task = current;
 304                         preempt_enable();
 305
 306                         err = __get_user(old, (unsigned int *) addr);
 307                         err |= __put_user(new, (unsigned int *) addr);
 308                         if (err)
 309                                 break;
 310                         rmb();
 311                 } while (!ll_bit);
 312         }
 313
 314         if (unlikely(err))
 315                 return err;
 316
 317         regs->regs[2] = old;
 318         regs->regs[7] = 0;      /* No error */
 319
 320         /*
 321          * Don't let your children do this ...
 322          */
 323         __asm__ __volatile__(
 324         "       move    $29, %0                                         \n"
 325         "       j       syscall_exit                                    \n"
 326         : /* no outputs */
 327         : "r" (regs));
 328
 329         /* unreached.  Honestly.  */
 330         while (1);
 331 }
 332
 333 save_static_function(sys_sysmips);
 334 static int __used noinline
 335 _sys_sysmips(nabi_no_regargs struct pt_regs regs)
 336 {
 337         long cmd, arg1, arg2, arg3;
 338
 339         cmd = regs.regs[4];
 340         arg1 = regs.regs[5];
 341         arg2 = regs.regs[6];
 342         arg3 = regs.regs[7];
 343
 344         switch (cmd) {
 345         case MIPS_ATOMIC_SET:
 346                 return mips_atomic_set(&regs, arg1, arg2);
 347
 348         case MIPS_FIXADE:
 349                 if (arg1 & ~3)
 350                         return -EINVAL;
 351
 352                 if (arg1 & 1)
 353                         set_thread_flag(TIF_FIXADE);
 354                 else
 355                         clear_thread_flag(TIF_FIXADE);
 356                 if (arg1 & 2)
 357                         set_thread_flag(TIF_LOGADE);
 358                 else
 359                         clear_thread_flag(TIF_FIXADE);
 360
 361                 return 0;
 362
 363         case FLUSH_CACHE:
 364                 __flush_cache_all();
 365                 return 0;
 366         }
 367
 368         return -EINVAL;
 369 }
 370
 371 /*
 372  * No implemented yet ...
 373  */
 374 SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
 375 {
 376         return -ENOSYS;
 377 }
 378
 379 /*
 380  * If we ever come here the user sp is bad.  Zap the process right away.
 381  * Due to the bad stack signaling wouldn't work.
 382  */
 383 asmlinkage void bad_stack(void)
 384 {
 385         do_exit(SIGSEGV);
 386 }
 387
 388 /*
 389  * Do a system call from kernel instead of calling sys_execve so we
 390  * end up with proper pt_regs.
 391  */
 392 int kernel_execve(const char *filename, char *const argv[], char *const envp[])
 393 {
 394         register unsigned long __a0 asm("$4") = (unsigned long) filename;
 395         register unsigned long __a1 asm("$5") = (unsigned long) argv;
 396         register unsigned long __a2 asm("$6") = (unsigned long) envp;
 397         register unsigned long __a3 asm("$7");
 398         unsigned long __v0;
 399
 400         __asm__ volatile ("                                     \n"
 401         "       .set    noreorder                               \n"
 402         "       li      $2, %5          # __NR_execve           \n"
 403         "       syscall                                         \n"
 404         "       move    %0, $2                                  \n"
 405         "       .set    reorder                                 \n"
 406         : "=&r" (__v0), "=r" (__a3)
 407         : "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_execve)
 408         : "$2", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24",
 409           "memory");
 410
 411         if (__a3 == 0)
 412                 return __v0;
 413
 414         return -__v0;
 415 }