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 #include <linux/sched/task_stack.h>
  30
  31 #include <asm/asm.h>
  32 #include <asm/asm-eva.h>
  33 #include <asm/branch.h>
  34 #include <asm/cachectl.h>
  35 #include <asm/cacheflush.h>
  36 #include <asm/asm-offsets.h>
  37 #include <asm/signal.h>
  38 #include <asm/sim.h>
  39 #include <asm/shmparam.h>
  40 #include <asm/sysmips.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         if (offset & ~PAGE_MASK)
  65                 return -EINVAL;
  66         return ksys_mmap_pgoff(addr, len, prot, flags, fd,
  67                                offset >> PAGE_SHIFT);
  68 }
  69
  70 SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
  71         unsigned long, prot, unsigned long, flags, unsigned long, fd,
  72         unsigned long, pgoff)
  73 {
  74         if (pgoff & (~PAGE_MASK >> 12))
  75                 return -EINVAL;
  76
  77         return ksys_mmap_pgoff(addr, len, prot, flags, fd,
  78                                pgoff >> (PAGE_SHIFT - 12));
  79 }
  80
  81 save_static_function(sys_fork);
  82 save_static_function(sys_clone);
  83
  84 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
  85 {
  86         struct thread_info *ti = task_thread_info(current);
  87
  88         ti->tp_value = addr;
  89         if (cpu_has_userlocal)
  90                 write_c0_userlocal(addr);
  91
  92         return 0;
  93 }
  94
  95 static inline int mips_atomic_set(unsigned long addr, unsigned long new)
  96 {
  97         unsigned long old, tmp;
  98         struct pt_regs *regs;
  99         unsigned int err;
 100
 101         if (unlikely(addr & 3))
 102                 return -EINVAL;
 103
 104         if (unlikely(!access_ok((const void __user *)addr, 4)))
 105                 return -EINVAL;
 106
 107         if (cpu_has_llsc && R10000_LLSC_WAR) {
 108                 __asm__ __volatile__ (
 109                 "       .set    push                                    \n"
 110                 "       .set    arch=r4000                              \n"
 111                 "       li      %[err], 0                               \n"
 112                 "1:     ll      %[old], (%[addr])                       \n"
 113                 "       move    %[tmp], %[new]                          \n"
 114                 "2:     sc      %[tmp], (%[addr])                       \n"
 115                 "       beqzl   %[tmp], 1b                              \n"
 116                 "3:                                                     \n"
 117                 "       .insn                                           \n"
 118                 "       .section .fixup,\"ax\"                          \n"
 119                 "4:     li      %[err], %[efault]                       \n"
 120                 "       j       3b                                      \n"
 121                 "       .previous                                       \n"
 122                 "       .section __ex_table,\"a\"                       \n"
 123                 "       "STR(PTR)"      1b, 4b                          \n"
 124                 "       "STR(PTR)"      2b, 4b                          \n"
 125                 "       .previous                                       \n"
 126                 "       .set    pop                                     \n"
 127                 : [old] "=&r" (old),
 128                   [err] "=&r" (err),
 129                   [tmp] "=&r" (tmp)
 130                 : [addr] "r" (addr),
 131                   [new] "r" (new),
 132                   [efault] "i" (-EFAULT)
 133                 : "memory");
 134         } else if (cpu_has_llsc) {
 135                 __asm__ __volatile__ (
 136                 "       .set    push                                    \n"
 137                 "       .set    "MIPS_ISA_ARCH_LEVEL"                   \n"
 138                 "       li      %[err], 0                               \n"
 139                 "1:                                                     \n"
 140                 user_ll("%[old]", "(%[addr])")
 141                 "       move    %[tmp], %[new]                          \n"
 142                 "2:                                                     \n"
 143                 user_sc("%[tmp]", "(%[addr])")
 144                 "       beqz    %[tmp], 1b                              \n"
 145                 "3:                                                     \n"
 146                 "       .insn                                           \n"
 147                 "       .section .fixup,\"ax\"                          \n"
 148                 "5:     li      %[err], %[efault]                       \n"
 149                 "       j       3b                                      \n"
 150                 "       .previous                                       \n"
 151                 "       .section __ex_table,\"a\"                       \n"
 152                 "       "STR(PTR)"      1b, 5b                          \n"
 153                 "       "STR(PTR)"      2b, 5b                          \n"
 154                 "       .previous                                       \n"
 155                 "       .set    pop                                     \n"
 156                 : [old] "=&r" (old),
 157                   [err] "=&r" (err),
 158                   [tmp] "=&r" (tmp)
 159                 : [addr] "r" (addr),
 160                   [new] "r" (new),
 161                   [efault] "i" (-EFAULT)
 162                 : "memory");
 163         } else {
 164                 do {
 165                         preempt_disable();
 166                         ll_bit = 1;
 167                         ll_task = current;
 168                         preempt_enable();
 169
 170                         err = __get_user(old, (unsigned int *) addr);
 171                         err |= __put_user(new, (unsigned int *) addr);
 172                         if (err)
 173                                 break;
 174                         rmb();
 175                 } while (!ll_bit);
 176         }
 177
 178         if (unlikely(err))
 179                 return err;
 180
 181         regs = current_pt_regs();
 182         regs->regs[2] = old;
 183         regs->regs[7] = 0;      /* No error */
 184
 185         /*
 186          * Don't let your children do this ...
 187          */
 188         __asm__ __volatile__(
 189         "       move    $29, %0                                         \n"
 190         "       j       syscall_exit                                    \n"
 191         : /* no outputs */
 192         : "r" (regs));
 193
 194         /* unreached.  Honestly.  */
 195         unreachable();
 196 }
 197
 198 /*
 199  * mips_atomic_set() normally returns directly via syscall_exit potentially
 200  * clobbering static registers, so be sure to preserve them.
 201  */
 202 save_static_function(sys_sysmips);
 203
 204 SYSCALL_DEFINE3(sysmips, long, cmd, long, arg1, long, arg2)
 205 {
 206         switch (cmd) {
 207         case MIPS_ATOMIC_SET:
 208                 return mips_atomic_set(arg1, arg2);
 209
 210         case MIPS_FIXADE:
 211                 if (arg1 & ~3)
 212                         return -EINVAL;
 213
 214                 if (arg1 & 1)
 215                         set_thread_flag(TIF_FIXADE);
 216                 else
 217                         clear_thread_flag(TIF_FIXADE);
 218                 if (arg1 & 2)
 219                         set_thread_flag(TIF_LOGADE);
 220                 else
 221                         clear_thread_flag(TIF_LOGADE);
 222
 223                 return 0;
 224
 225         case FLUSH_CACHE:
 226                 __flush_cache_all();
 227                 return 0;
 228         }
 229
 230         return -EINVAL;
 231 }
 232
 233 /*
 234  * No implemented yet ...
 235  */
 236 SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
 237 {
 238         return -ENOSYS;
 239 }
 240
 241 /*
 242  * If we ever come here the user sp is bad.  Zap the process right away.
 243  * Due to the bad stack signaling wouldn't work.
 244  */
 245 asmlinkage void bad_stack(void)
 246 {
 247         do_exit(SIGSEGV);
 248 }