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syscall.h
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1 /*
2  * Access to user system call parameters and results
3  *
4  * Copyright (C) 2008 Red Hat, Inc. All rights reserved.
5  *
6  * This copyrighted material is made available to anyone wishing to use,
7  * modify, copy, or redistribute it subject to the terms and conditions
8  * of the GNU General Public License v.2.
9  *
10  * See asm-generic/syscall.h for descriptions of what we must do here.
11  */
12 
13 #ifndef _ASM_SYSCALL_H
14 #define _ASM_SYSCALL_H 1
15 
16 #include <linux/sched.h>
17 
18 /* ftrace syscalls requires exporting the sys_call_table */
19 #ifdef CONFIG_FTRACE_SYSCALLS
20 extern const unsigned long *sys_call_table;
21 #endif /* CONFIG_FTRACE_SYSCALLS */
22 
23 static inline long syscall_get_nr(struct task_struct *task,
24  struct pt_regs *regs)
25 {
26  return TRAP(regs) == 0xc00 ? regs->gpr[0] : -1L;
27 }
28 
29 static inline void syscall_rollback(struct task_struct *task,
30  struct pt_regs *regs)
31 {
32  regs->gpr[3] = regs->orig_gpr3;
33 }
34 
35 static inline long syscall_get_error(struct task_struct *task,
36  struct pt_regs *regs)
37 {
38  return (regs->ccr & 0x10000000) ? -regs->gpr[3] : 0;
39 }
40 
41 static inline long syscall_get_return_value(struct task_struct *task,
42  struct pt_regs *regs)
43 {
44  return regs->gpr[3];
45 }
46 
47 static inline void syscall_set_return_value(struct task_struct *task,
48  struct pt_regs *regs,
49  int error, long val)
50 {
51  if (error) {
52  regs->ccr |= 0x10000000L;
53  regs->gpr[3] = -error;
54  } else {
55  regs->ccr &= ~0x10000000L;
56  regs->gpr[3] = val;
57  }
58 }
59 
60 static inline void syscall_get_arguments(struct task_struct *task,
61  struct pt_regs *regs,
62  unsigned int i, unsigned int n,
63  unsigned long *args)
64 {
65  BUG_ON(i + n > 6);
66 #ifdef CONFIG_PPC64
67  if (test_tsk_thread_flag(task, TIF_32BIT)) {
68  /*
69  * Zero-extend 32-bit argument values. The high bits are
70  * garbage ignored by the actual syscall dispatch.
71  */
72  while (n-- > 0)
73  args[n] = (u32) regs->gpr[3 + i + n];
74  return;
75  }
76 #endif
77  memcpy(args, &regs->gpr[3 + i], n * sizeof(args[0]));
78 }
79 
80 static inline void syscall_set_arguments(struct task_struct *task,
81  struct pt_regs *regs,
82  unsigned int i, unsigned int n,
83  const unsigned long *args)
84 {
85  BUG_ON(i + n > 6);
86  memcpy(&regs->gpr[3 + i], args, n * sizeof(args[0]));
87 }
88 
89 #endif /* _ASM_SYSCALL_H */