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/fs.h>
  14 #include <linux/smp.h>
  15 #include <linux/ptrace.h>
  16 #include <linux/string.h>
  17 #include <linux/syscalls.h>
  18 #include <linux/file.h>
  19 #include <linux/utsname.h>
  20 #include <linux/unistd.h>
  21 #include <linux/sem.h>
  22 #include <linux/msg.h>
  23 #include <linux/shm.h>
  24 #include <linux/compiler.h>
  25 #include <linux/ipc.h>
  26 #include <linux/uaccess.h>
  27 #include <linux/slab.h>
  28 #include <linux/elf.h>
  29
  30 #include <asm/asm.h>
  31 #include <asm/asm-eva.h>
  32 #include <asm/branch.h>
  33 #include <asm/cachectl.h>
  34 #include <asm/cacheflush.h>
  35 #include <asm/asm-offsets.h>
  36 #include <asm/signal.h>
  37 #include <asm/sim.h>
  38 #include <asm/shmparam.h>
  39 #include <asm/sysmips.h>
  40 #include <asm/uaccess.h>
  41 #include <asm/switch_to.h>
  42
  43 /*
  44  * For historic reasons the pipe(2) syscall on MIPS has an unusual calling
  45  * convention.  It returns results in registers $v0 / $v1 which means there
  46  * is no need for it to do verify the validity of a userspace pointer
  47  * argument.  Historically that used to be expensive in Linux.  These days
  48  * the performance advantage is negligible.
  49  */
  50 asmlinkage int sysm_pipe(void)
  51 {
  52         int fd[2];
  53         int error = do_pipe_flags(fd, 0);
  54         if (error)
  55                 return error;
  56         current_pt_regs()->regs[3] = fd[1];
  57         return fd[0];
  58 }
  59
  60 SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
  61         unsigned long, prot, unsigned long, flags, unsigned long,
  62         fd, off_t, offset)
  63 {
  64         unsigned long result;
  65
  66         result = -EINVAL;
  67         if (offset & ~PAGE_MASK)
  68                 goto out;
  69
  70         result = sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
  71
  72 out:
  73         return result;
  74 }
  75
  76 SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
  77         unsigned long, prot, unsigned long, flags, unsigned long, fd,
  78         unsigned long, pgoff)
  79 {
  80         if (pgoff & (~PAGE_MASK >> 12))
  81                 return -EINVAL;
  82
  83         return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
  84 }
  85
  86 save_static_function(sys_fork);
  87 save_static_function(sys_clone);
  88
  89 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
  90 {
  91         struct thread_info *ti = task_thread_info(current);
  92
  93         ti->tp_value = addr;
  94         if (cpu_has_userlocal)
  95                 write_c0_userlocal(addr);
  96
  97         return 0;
  98 }
  99
 100 static inline int mips_atomic_set(unsigned long addr, unsigned long new)
 101 {
 102         unsigned long old, tmp;
 103         struct pt_regs *regs;
 104         unsigned int err;
 105
 106         if (unlikely(addr & 3))
 107                 return -EINVAL;
 108
 109         if (unlikely(!access_ok(VERIFY_WRITE, addr, 4)))
 110                 return -EINVAL;
 111
 112         if (cpu_has_llsc && R10000_LLSC_WAR) {
 113                 __asm__ __volatile__ (
 114                 "       .set    arch=r4000                              \n"
 115                 "       li      %[err], 0                               \n"
 116                 "1:     ll      %[old], (%[addr])                       \n"
 117                 "       move    %[tmp], %[new]                          \n"
 118                 "2:     sc      %[tmp], (%[addr])                       \n"
 119                 "       beqzl   %[tmp], 1b                              \n"
 120                 "3:                                                     \n"
 121                 "       .insn                                           \n"
 122                 "       .section .fixup,\"ax\"                          \n"
 123                 "4:     li      %[err], %[efault]                       \n"
 124                 "       j       3b                                      \n"
 125                 "       .previous                                       \n"
 126                 "       .section __ex_table,\"a\"                       \n"
 127                 "       "STR(PTR)"      1b, 4b                          \n"
 128                 "       "STR(PTR)"      2b, 4b                          \n"
 129                 "       .previous                                       \n"
 130                 "       .set    mips0                                   \n"
 131                 : [old] "=&r" (old),
 132                   [err] "=&r" (err),
 133                   [tmp] "=&r" (tmp)
 134                 : [addr] "r" (addr),
 135                   [new] "r" (new),
 136                   [efault] "i" (-EFAULT)
 137                 : "memory");
 138         } else if (cpu_has_llsc) {
 139                 __asm__ __volatile__ (
 140                 "       .set    "MIPS_ISA_ARCH_LEVEL"                   \n"
 141                 "       li      %[err], 0                               \n"
 142                 "1:                                                     \n"
 143                 user_ll("%[old]", "(%[addr])")
 144                 "       move    %[tmp], %[new]                          \n"
 145                 "2:                                                     \n"
 146                 user_sc("%[tmp]", "(%[addr])")
 147                 "       beqz    %[tmp], 4f                              \n"
 148                 "3:                                                     \n"
 149                 "       .insn                                           \n"
 150                 "       .subsection 2                                   \n"
 151                 "4:     b       1b                                      \n"
 152                 "       .previous                                       \n"
 153                 "                                                       \n"
 154                 "       .section .fixup,\"ax\"                          \n"
 155                 "5:     li      %[err], %[efault]                       \n"
 156                 "       j       3b                                      \n"
 157                 "       .previous                                       \n"
 158                 "       .section __ex_table,\"a\"                       \n"
 159                 "       "STR(PTR)"      1b, 5b                          \n"
 160                 "       "STR(PTR)"      2b, 5b                          \n"
 161                 "       .previous                                       \n"
 162                 "       .set    mips0                                   \n"
 163                 : [old] "=&r" (old),
 164                   [err] "=&r" (err),
 165                   [tmp] "=&r" (tmp)
 166                 : [addr] "r" (addr),
 167                   [new] "r" (new),
 168                   [efault] "i" (-EFAULT)
 169                 : "memory");
 170         } else {
 171                 do {
 172                         preempt_disable();
 173                         ll_bit = 1;
 174                         ll_task = current;
 175                         preempt_enable();
 176
 177                         err = __get_user(old, (unsigned int *) addr);
 178                         err |= __put_user(new, (unsigned int *) addr);
 179                         if (err)
 180                                 break;
 181                         rmb();
 182                 } while (!ll_bit);
 183         }
 184
 185         if (unlikely(err))
 186                 return err;
 187
 188         regs = current_pt_regs();
 189         regs->regs[2] = old;
 190         regs->regs[7] = 0;      /* No error */
 191
 192         /*
 193          * Don't let your children do this ...
 194          */
 195         __asm__ __volatile__(
 196         "       move    $29, %0                                         \n"
 197         "       j       syscall_exit                                    \n"
 198         : /* no outputs */
 199         : "r" (regs));
 200
 201         /* unreached.  Honestly.  */
 202         unreachable();
 203 }
 204
 205 /*
 206  * mips_atomic_set() normally returns directly via syscall_exit potentially
 207  * clobbering static registers, so be sure to preserve them.
 208  */
 209 save_static_function(sys_sysmips);
 210
 211 SYSCALL_DEFINE3(sysmips, long, cmd, long, arg1, long, arg2)
 212 {
 213         switch (cmd) {
 214         case MIPS_ATOMIC_SET:
 215                 return mips_atomic_set(arg1, arg2);
 216
 217         case MIPS_FIXADE:
 218                 if (arg1 & ~3)
 219                         return -EINVAL;
 220
 221                 if (arg1 & 1)
 222                         set_thread_flag(TIF_FIXADE);
 223                 else
 224                         clear_thread_flag(TIF_FIXADE);
 225                 if (arg1 & 2)
 226                         set_thread_flag(TIF_LOGADE);
 227                 else
 228                         clear_thread_flag(TIF_LOGADE);
 229
 230                 return 0;
 231
 232         case FLUSH_CACHE:
 233                 __flush_cache_all();
 234                 return 0;
 235         }
 236
 237         return -EINVAL;
 238 }
 239
 240 /*
 241  * No implemented yet ...
 242  */
 243 SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
 244 {
 245         return -ENOSYS;
 246 }
 247
 248 /*
 249  * If we ever come here the user sp is bad.  Zap the process right away.
 250  * Due to the bad stack signaling wouldn't work.
 251  */
 252 asmlinkage void bad_stack(void)
 253 {
 254         do_exit(SIGSEGV);
 255 }