arch/mips/include/asm/syscall.h

   1 /*
   2  * Access to user system call parameters and results
   3  *
   4  * This file is subject to the terms and conditions of the GNU General Public
   5  * License.  See the file "COPYING" in the main directory of this archive
   6  * for more details.
   7  *
   8  * See asm-generic/syscall.h for descriptions of what we must do here.
   9  *
  10  * Copyright (C) 2012 Ralf Baechle <ralf@linux-mips.org>
  11  */
  12
  13 #ifndef __ASM_MIPS_SYSCALL_H
  14 #define __ASM_MIPS_SYSCALL_H
  15
  16 #include <linux/compiler.h>
  17 #include <uapi/linux/audit.h>
  18 #include <linux/elf-em.h>
  19 #include <linux/kernel.h>
  20 #include <linux/sched.h>
  21 #include <linux/uaccess.h>
  22 #include <asm/ptrace.h>
  23 #include <asm/unistd.h>
  24
  25 #ifndef __NR_syscall /* Only defined if _MIPS_SIM == _MIPS_SIM_ABI32 */
  26 #define __NR_syscall 4000
  27 #endif
  28
  29 static inline long syscall_get_nr(struct task_struct *task,
  30                                   struct pt_regs *regs)
  31 {
  32         return current_thread_info()->syscall;
  33 }
  34
  35 static inline unsigned long mips_get_syscall_arg(unsigned long *arg,
  36         struct task_struct *task, struct pt_regs *regs, unsigned int n)
  37 {
  38         unsigned long usp __maybe_unused = regs->regs[29];
  39
  40         switch (n) {
  41         case 0: case 1: case 2: case 3:
  42                 *arg = regs->regs[4 + n];
  43
  44                 return 0;
  45
  46 #ifdef CONFIG_32BIT
  47         case 4: case 5: case 6: case 7:
  48                 return get_user(*arg, (int *)usp + n);
  49 #endif
  50
  51 #ifdef CONFIG_64BIT
  52         case 4: case 5: case 6: case 7:
  53 #ifdef CONFIG_MIPS32_O32
  54                 if (test_thread_flag(TIF_32BIT_REGS))
  55                         return get_user(*arg, (int *)usp + n);
  56                 else
  57 #endif
  58                         *arg = regs->regs[4 + n];
  59
  60                 return 0;
  61 #endif
  62
  63         default:
  64                 BUG();
  65         }
  66
  67         unreachable();
  68 }
  69
  70 static inline long syscall_get_return_value(struct task_struct *task,
  71                                             struct pt_regs *regs)
  72 {
  73         return regs->regs[2];
  74 }
  75
  76 static inline void syscall_rollback(struct task_struct *task,
  77                                     struct pt_regs *regs)
  78 {
  79         /* Do nothing */
  80 }
  81
  82 static inline void syscall_set_return_value(struct task_struct *task,
  83                                             struct pt_regs *regs,
  84                                             int error, long val)
  85 {
  86         if (error) {
  87                 regs->regs[2] = -error;
  88                 regs->regs[7] = -1;
  89         } else {
  90                 regs->regs[2] = val;
  91                 regs->regs[7] = 0;
  92         }
  93 }
  94
  95 static inline void syscall_get_arguments(struct task_struct *task,
  96                                          struct pt_regs *regs,
  97                                          unsigned int i, unsigned int n,
  98                                          unsigned long *args)
  99 {
 100         int ret;
 101         /* O32 ABI syscall() - Either 64-bit with O32 or 32-bit */
 102         if ((config_enabled(CONFIG_32BIT) ||
 103             test_tsk_thread_flag(task, TIF_32BIT_REGS)) &&
 104             (regs->regs[2] == __NR_syscall)) {
 105                 i++;
 106                 n++;
 107         }
 108
 109         while (n--)
 110                 ret |= mips_get_syscall_arg(args++, task, regs, i++);
 111
 112         /*
 113          * No way to communicate an error because this is a void function.
 114          */
 115 #if 0
 116         return ret;
 117 #endif
 118 }
 119
 120 extern const unsigned long sys_call_table[];
 121 extern const unsigned long sys32_call_table[];
 122 extern const unsigned long sysn32_call_table[];
 123
 124 static inline int syscall_get_arch(void)
 125 {
 126         int arch = AUDIT_ARCH_MIPS;
 127 #ifdef CONFIG_64BIT
 128         if (!test_thread_flag(TIF_32BIT_REGS)) {
 129                 arch |= __AUDIT_ARCH_64BIT;
 130                 /* N32 sets only TIF_32BIT_ADDR */
 131                 if (test_thread_flag(TIF_32BIT_ADDR))
 132                         arch |= __AUDIT_ARCH_CONVENTION_MIPS64_N32;
 133         }
 134 #endif
 135 #if defined(__LITTLE_ENDIAN)
 136         arch |=  __AUDIT_ARCH_LE;
 137 #endif
 138         return arch;
 139 }
 140
 141 #endif  /* __ASM_MIPS_SYSCALL_H */