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