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/switch_to.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(void)
  52 {
  53         int fd[2];
  54         int error = do_pipe_flags(fd, 0);
  55         if (error)
  56                 return error;
  57         current_pt_regs()->regs[3] = fd[1];
  58         return fd[0];
  59 }
  60
  61 SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
  62         unsigned long, prot, unsigned long, flags, unsigned long,
  63         fd, off_t, offset)
  64 {
  65         if (offset & ~PAGE_MASK)
  66                 return -EINVAL;
  67         return ksys_mmap_pgoff(addr, len, prot, flags, fd,
  68                                offset >> PAGE_SHIFT);
  69 }
  70
  71 SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
  72         unsigned long, prot, unsigned long, flags, unsigned long, fd,
  73         unsigned long, pgoff)
  74 {
  75         if (pgoff & (~PAGE_MASK >> 12))
  76                 return -EINVAL;
  77
  78         return ksys_mmap_pgoff(addr, len, prot, flags, fd,
  79                                pgoff >> (PAGE_SHIFT - 12));
  80 }
  81
  82 save_static_function(sys_fork);
  83 save_static_function(sys_clone);
  84 save_static_function(sys_clone3);
  85
  86 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
  87 {
  88         struct thread_info *ti = task_thread_info(current);
  89
  90         ti->tp_value = addr;
  91         if (cpu_has_userlocal)
  92                 write_c0_userlocal(addr);
  93
  94         return 0;
  95 }
  96
  97 static inline int mips_atomic_set(unsigned long addr, unsigned long new)
  98 {
  99         unsigned long old, tmp;
 100         struct pt_regs *regs;
 101         unsigned int err;
 102
 103         if (unlikely(addr & 3))
 104                 return -EINVAL;
 105
 106         if (unlikely(!access_ok((const void __user *)addr, 4)))
 107                 return -EINVAL;
 108
 109         if (cpu_has_llsc && IS_ENABLED(CONFIG_WAR_R10000_LLSC)) {
 110                 __asm__ __volatile__ (
 111                 "       .set    push                                    \n"
 112                 "       .set    arch=r4000                              \n"
 113                 "       li      %[err], 0                               \n"
 114                 "1:     ll      %[old], (%[addr])                       \n"
 115                 "       move    %[tmp], %[new]                          \n"
 116                 "2:     sc      %[tmp], (%[addr])                       \n"
 117                 "       beqzl   %[tmp], 1b                              \n"
 118                 "3:                                                     \n"
 119                 "       .insn                                           \n"
 120                 "       .section .fixup,\"ax\"                          \n"
 121                 "4:     li      %[err], %[efault]                       \n"
 122                 "       j       3b                                      \n"
 123                 "       .previous                                       \n"
 124                 "       .section __ex_table,\"a\"                       \n"
 125                 "       "STR(PTR)"      1b, 4b                          \n"
 126                 "       "STR(PTR)"      2b, 4b                          \n"
 127                 "       .previous                                       \n"
 128                 "       .set    pop                                     \n"
 129                 : [old] "=&r" (old),
 130                   [err] "=&r" (err),
 131                   [tmp] "=&r" (tmp)
 132                 : [addr] "r" (addr),
 133                   [new] "r" (new),
 134                   [efault] "i" (-EFAULT)
 135                 : "memory");
 136         } else if (cpu_has_llsc) {
 137                 __asm__ __volatile__ (
 138                 "       .set    push                                    \n"
 139                 "       .set    "MIPS_ISA_ARCH_LEVEL"                   \n"
 140                 "       li      %[err], 0                               \n"
 141                 "1:                                                     \n"
 142                 "       " __SYNC(full, loongson3_war) "                 \n"
 143                 user_ll("%[old]", "(%[addr])")
 144                 "       move    %[tmp], %[new]                          \n"
 145                 "2:                                                     \n"
 146                 user_sc("%[tmp]", "(%[addr])")
 147                 "       beqz    %[tmp], 1b                              \n"
 148                 "3:                                                     \n"
 149                 "       .insn                                           \n"
 150                 "       .section .fixup,\"ax\"                          \n"
 151                 "5:     li      %[err], %[efault]                       \n"
 152                 "       j       3b                                      \n"
 153                 "       .previous                                       \n"
 154                 "       .section __ex_table,\"a\"                       \n"
 155                 "       "STR(PTR)"      1b, 5b                          \n"
 156                 "       "STR(PTR)"      2b, 5b                          \n"
 157                 "       .previous                                       \n"
 158                 "       .set    pop                                     \n"
 159                 : [old] "=&r" (old),
 160                   [err] "=&r" (err),
 161                   [tmp] "=&r" (tmp)
 162                 : [addr] "r" (addr),
 163                   [new] "r" (new),
 164                   [efault] "i" (-EFAULT)
 165                 : "memory");
 166         } else {
 167                 do {
 168                         preempt_disable();
 169                         ll_bit = 1;
 170                         ll_task = current;
 171                         preempt_enable();
 172
 173                         err = __get_user(old, (unsigned int *) addr);
 174                         err |= __put_user(new, (unsigned int *) addr);
 175                         if (err)
 176                                 break;
 177                         rmb();
 178                 } while (!ll_bit);
 179         }
 180
 181         if (unlikely(err))
 182                 return err;
 183
 184         regs = current_pt_regs();
 185         regs->regs[2] = old;
 186         regs->regs[7] = 0;      /* No error */
 187
 188         /*
 189          * Don't let your children do this ...
 190          */
 191         __asm__ __volatile__(
 192         "       move    $29, %0                                         \n"
 193         "       j       syscall_exit                                    \n"
 194         : /* no outputs */
 195         : "r" (regs));
 196
 197         /* unreached.  Honestly.  */
 198         unreachable();
 199 }
 200
 201 /*
 202  * mips_atomic_set() normally returns directly via syscall_exit potentially
 203  * clobbering static registers, so be sure to preserve them.
 204  */
 205 save_static_function(sys_sysmips);
 206
 207 SYSCALL_DEFINE3(sysmips, long, cmd, long, arg1, long, arg2)
 208 {
 209         switch (cmd) {
 210         case MIPS_ATOMIC_SET:
 211                 return mips_atomic_set(arg1, arg2);
 212
 213         case MIPS_FIXADE:
 214                 if (arg1 & ~3)
 215                         return -EINVAL;
 216
 217                 if (arg1 & 1)
 218                         set_thread_flag(TIF_FIXADE);
 219                 else
 220                         clear_thread_flag(TIF_FIXADE);
 221                 if (arg1 & 2)
 222                         set_thread_flag(TIF_LOGADE);
 223                 else
 224                         clear_thread_flag(TIF_LOGADE);
 225
 226                 return 0;
 227
 228         case FLUSH_CACHE:
 229                 __flush_cache_all();
 230                 return 0;
 231         }
 232
 233         return -EINVAL;
 234 }
 235
 236 /*
 237  * No implemented yet ...
 238  */
 239 SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
 240 {
 241         return -ENOSYS;
 242 }
 243
 244 /*
 245  * If we ever come here the user sp is bad.  Zap the process right away.
 246  * Due to the bad stack signaling wouldn't work.
 247  */
 248 asmlinkage void bad_stack(void)
 249 {
 250         do_exit(SIGSEGV);
 251 }