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/sync.h>
  41 #include <asm/sysmips.h>
  42 #include <asm/syscalls.h>
  43 #include <asm/switch_to.h>
  44
  45 /*
  46  * For historic reasons the pipe(2) syscall on MIPS has an unusual calling
  47  * convention.  It returns results in registers $v0 / $v1 which means there
  48  * is no need for it to do verify the validity of a userspace pointer
  49  * argument.  Historically that used to be expensive in Linux.  These days
  50  * the performance advantage is negligible.
  51  */
  52 asmlinkage int sysm_pipe(void)
  53 {
  54         int fd[2];
  55         int error = do_pipe_flags(fd, 0);
  56         if (error)
  57                 return error;
  58         current_pt_regs()->regs[3] = fd[1];
  59         return fd[0];
  60 }
  61
  62 SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
  63         unsigned long, prot, unsigned long, flags, unsigned long,
  64         fd, off_t, offset)
  65 {
  66         if (offset & ~PAGE_MASK)
  67                 return -EINVAL;
  68         return ksys_mmap_pgoff(addr, len, prot, flags, fd,
  69                                offset >> PAGE_SHIFT);
  70 }
  71
  72 SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
  73         unsigned long, prot, unsigned long, flags, unsigned long, fd,
  74         unsigned long, pgoff)
  75 {
  76         if (pgoff & (~PAGE_MASK >> 12))
  77                 return -EINVAL;
  78
  79         return ksys_mmap_pgoff(addr, len, prot, flags, fd,
  80                                pgoff >> (PAGE_SHIFT - 12));
  81 }
  82
  83 save_static_function(sys_fork);
  84 save_static_function(sys_clone);
  85 save_static_function(sys_clone3);
  86
  87 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
  88 {
  89         struct thread_info *ti = task_thread_info(current);
  90
  91         ti->tp_value = addr;
  92         if (cpu_has_userlocal)
  93                 write_c0_userlocal(addr);
  94
  95         return 0;
  96 }
  97
  98 static inline int mips_atomic_set(unsigned long addr, unsigned long new)
  99 {
 100         unsigned long old, tmp;
 101         struct pt_regs *regs;
 102         unsigned int err;
 103
 104         if (unlikely(addr & 3))
 105                 return -EINVAL;
 106
 107         if (unlikely(!access_ok((const void __user *)addr, 4)))
 108                 return -EINVAL;
 109
 110         if (cpu_has_llsc && IS_ENABLED(CONFIG_WAR_R10000_LLSC)) {
 111                 __asm__ __volatile__ (
 112                 "       .set    push                                    \n"
 113                 "       .set    arch=r4000                              \n"
 114                 "       li      %[err], 0                               \n"
 115                 "1:     ll      %[old], (%[addr])                       \n"
 116                 "       move    %[tmp], %[new]                          \n"
 117                 "2:     sc      %[tmp], (%[addr])                       \n"
 118                 "       beqzl   %[tmp], 1b                              \n"
 119                 "3:                                                     \n"
 120                 "       .insn                                           \n"
 121                 "       .section .fixup,\"ax\"                          \n"
 122                 "4:     li      %[err], %[efault]                       \n"
 123                 "       j       3b                                      \n"
 124                 "       .previous                                       \n"
 125                 "       .section __ex_table,\"a\"                       \n"
 126                 "       "STR(PTR_WD)"   1b, 4b                          \n"
 127                 "       "STR(PTR_WD)"   2b, 4b                          \n"
 128                 "       .previous                                       \n"
 129                 "       .set    pop                                     \n"
 130                 : [old] "=&r" (old),
 131                   [err] "=&r" (err),
 132                   [tmp] "=&r" (tmp)
 133                 : [addr] "r" (addr),
 134                   [new] "r" (new),
 135                   [efault] "i" (-EFAULT)
 136                 : "memory");
 137         } else if (cpu_has_llsc) {
 138                 __asm__ __volatile__ (
 139                 "       .set    push                                    \n"
 140                 "       .set    "MIPS_ISA_ARCH_LEVEL"                   \n"
 141                 "       li      %[err], 0                               \n"
 142                 "1:                                                     \n"
 143                 "       " __SYNC(full, loongson3_war) "                 \n"
 144                 user_ll("%[old]", "(%[addr])")
 145                 "       move    %[tmp], %[new]                          \n"
 146                 "2:                                                     \n"
 147                 user_sc("%[tmp]", "(%[addr])")
 148                 "       beqz    %[tmp], 1b                              \n"
 149                 "3:                                                     \n"
 150                 "       .insn                                           \n"
 151                 "       .section .fixup,\"ax\"                          \n"
 152                 "5:     li      %[err], %[efault]                       \n"
 153                 "       j       3b                                      \n"
 154                 "       .previous                                       \n"
 155                 "       .section __ex_table,\"a\"                       \n"
 156                 "       "STR(PTR_WD)"   1b, 5b                          \n"
 157                 "       "STR(PTR_WD)"   2b, 5b                          \n"
 158                 "       .previous                                       \n"
 159                 "       .set    pop                                     \n"
 160                 : [old] "=&r" (old),
 161                   [err] "=&r" (err),
 162                   [tmp] "=&r" (tmp)
 163                 : [addr] "r" (addr),
 164                   [new] "r" (new),
 165                   [efault] "i" (-EFAULT)
 166                 : "memory");
 167         } else {
 168                 do {
 169                         preempt_disable();
 170                         ll_bit = 1;
 171                         ll_task = current;
 172                         preempt_enable();
 173
 174                         err = __get_user(old, (unsigned int *) addr);
 175                         err |= __put_user(new, (unsigned int *) addr);
 176                         if (err)
 177                                 break;
 178                         rmb();
 179                 } while (!ll_bit);
 180         }
 181
 182         if (unlikely(err))
 183                 return err;
 184
 185         regs = current_pt_regs();
 186         regs->regs[2] = old;
 187         regs->regs[7] = 0;      /* No error */
 188
 189         /*
 190          * Don't let your children do this ...
 191          */
 192         __asm__ __volatile__(
 193         "       move    $29, %0                                         \n"
 194         "       j       syscall_exit                                    \n"
 195         : /* no outputs */
 196         : "r" (regs));
 197
 198         /* unreached.  Honestly.  */
 199         unreachable();
 200 }
 201
 202 /*
 203  * mips_atomic_set() normally returns directly via syscall_exit potentially
 204  * clobbering static registers, so be sure to preserve them.
 205  */
 206 save_static_function(sys_sysmips);
 207
 208 SYSCALL_DEFINE3(sysmips, long, cmd, long, arg1, long, arg2)
 209 {
 210         switch (cmd) {
 211         case MIPS_ATOMIC_SET:
 212                 return mips_atomic_set(arg1, arg2);
 213
 214         case MIPS_FIXADE:
 215                 if (arg1 & ~3)
 216                         return -EINVAL;
 217
 218                 if (arg1 & 1)
 219                         set_thread_flag(TIF_FIXADE);
 220                 else
 221                         clear_thread_flag(TIF_FIXADE);
 222                 if (arg1 & 2)
 223                         set_thread_flag(TIF_LOGADE);
 224                 else
 225                         clear_thread_flag(TIF_LOGADE);
 226
 227                 return 0;
 228
 229         case FLUSH_CACHE:
 230                 __flush_cache_all();
 231                 return 0;
 232         }
 233
 234         return -EINVAL;
 235 }
 236
 237 /*
 238  * No implemented yet ...
 239  */
 240 SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
 241 {
 242         return -ENOSYS;
 243 }