arch/riscv/include/asm/syscall.h

   1 /*
   2  * Copyright (C) 2008-2009 Red Hat, Inc.  All rights reserved.
   3  * Copyright 2010 Tilera Corporation. All Rights Reserved.
   4  * Copyright 2015 Regents of the University of California, Berkeley
   5  *
   6  *   This program is free software; you can redistribute it and/or
   7  *   modify it under the terms of the GNU General Public License
   8  *   as published by the Free Software Foundation, version 2.
   9  *
  10  *   This program is distributed in the hope that it will be useful,
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *   GNU General Public License for more details.
  14  *
  15  * See asm-generic/syscall.h for descriptions of what we must do here.
  16  */
  17
  18 #ifndef _ASM_RISCV_SYSCALL_H
  19 #define _ASM_RISCV_SYSCALL_H
  20
  21 #include <linux/sched.h>
  22 #include <linux/err.h>
  23
  24 /* The array of function pointers for syscalls. */
  25 extern void *sys_call_table[];
  26
  27 /*
  28  * Only the low 32 bits of orig_r0 are meaningful, so we return int.
  29  * This importantly ignores the high bits on 64-bit, so comparisons
  30  * sign-extend the low 32 bits.
  31  */
  32 static inline int syscall_get_nr(struct task_struct *task,
  33                                  struct pt_regs *regs)
  34 {
  35         return regs->a7;
  36 }
  37
  38 static inline void syscall_set_nr(struct task_struct *task,
  39                                   struct pt_regs *regs,
  40                                   int sysno)
  41 {
  42         regs->a7 = sysno;
  43 }
  44
  45 static inline void syscall_rollback(struct task_struct *task,
  46                                     struct pt_regs *regs)
  47 {
  48         regs->a0 = regs->orig_a0;
  49 }
  50
  51 static inline long syscall_get_error(struct task_struct *task,
  52                                      struct pt_regs *regs)
  53 {
  54         unsigned long error = regs->a0;
  55
  56         return IS_ERR_VALUE(error) ? error : 0;
  57 }
  58
  59 static inline long syscall_get_return_value(struct task_struct *task,
  60                                             struct pt_regs *regs)
  61 {
  62         return regs->a0;
  63 }
  64
  65 static inline void syscall_set_return_value(struct task_struct *task,
  66                                             struct pt_regs *regs,
  67                                             int error, long val)
  68 {
  69         regs->a0 = (long) error ?: val;
  70 }
  71
  72 static inline void syscall_get_arguments(struct task_struct *task,
  73                                          struct pt_regs *regs,
  74                                          unsigned int i, unsigned int n,
  75                                          unsigned long *args)
  76 {
  77         BUG_ON(i + n > 6);
  78         if (i == 0) {
  79                 args[0] = regs->orig_a0;
  80                 args++;
  81                 i++;
  82                 n--;
  83         }
  84         memcpy(args, &regs->a1 + i * sizeof(regs->a1), n * sizeof(args[0]));
  85 }
  86
  87 static inline void syscall_set_arguments(struct task_struct *task,
  88                                          struct pt_regs *regs,
  89                                          unsigned int i, unsigned int n,
  90                                          const unsigned long *args)
  91 {
  92         BUG_ON(i + n > 6);
  93         if (i == 0) {
  94                 regs->orig_a0 = args[0];
  95                 args++;
  96                 i++;
  97                 n--;
  98         }
  99         memcpy(&regs->a1 + i * sizeof(regs->a1), args, n * sizeof(regs->a0));
 100 }
 101
 102 #endif  /* _ASM_RISCV_SYSCALL_H */