1 /*
2 * Access to user system call parameters and results
3 *
4 * Copyright (C) 2008 Imagination Technologies Ltd.
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_METAG_SYSCALL_H
14 #define _ASM_METAG_SYSCALL_H
15
16 #include <linux/sched.h>
17 #include <linux/err.h>
18 #include <linux/uaccess.h>
19
20 #include <asm/switch.h>
21
syscall_get_nr(struct task_struct * task,struct pt_regs * regs)22 static inline long syscall_get_nr(struct task_struct *task,
23 struct pt_regs *regs)
24 {
25 unsigned long insn;
26
27 /*
28 * FIXME there's no way to find out how we got here other than to
29 * examine the memory at the PC to see if it is a syscall
30 * SWITCH instruction.
31 */
32 if (get_user(insn, (unsigned long *)(regs->ctx.CurrPC - 4)))
33 return -1;
34
35 if (insn == __METAG_SW_ENCODING(SYS))
36 return regs->ctx.DX[0].U1;
37 else
38 return -1L;
39 }
40
syscall_rollback(struct task_struct * task,struct pt_regs * regs)41 static inline void syscall_rollback(struct task_struct *task,
42 struct pt_regs *regs)
43 {
44 /* do nothing */
45 }
46
syscall_get_error(struct task_struct * task,struct pt_regs * regs)47 static inline long syscall_get_error(struct task_struct *task,
48 struct pt_regs *regs)
49 {
50 unsigned long error = regs->ctx.DX[0].U0;
51 return IS_ERR_VALUE(error) ? error : 0;
52 }
53
syscall_get_return_value(struct task_struct * task,struct pt_regs * regs)54 static inline long syscall_get_return_value(struct task_struct *task,
55 struct pt_regs *regs)
56 {
57 return regs->ctx.DX[0].U0;
58 }
59
syscall_set_return_value(struct task_struct * task,struct pt_regs * regs,int error,long val)60 static inline void syscall_set_return_value(struct task_struct *task,
61 struct pt_regs *regs,
62 int error, long val)
63 {
64 regs->ctx.DX[0].U0 = (long) error ?: val;
65 }
66
syscall_get_arguments(struct task_struct * task,struct pt_regs * regs,unsigned int i,unsigned int n,unsigned long * args)67 static inline void syscall_get_arguments(struct task_struct *task,
68 struct pt_regs *regs,
69 unsigned int i, unsigned int n,
70 unsigned long *args)
71 {
72 unsigned int reg, j;
73 BUG_ON(i + n > 6);
74
75 for (j = i, reg = 6 - i; j < (i + n); j++, reg--) {
76 if (reg % 2)
77 args[j] = regs->ctx.DX[(reg + 1) / 2].U0;
78 else
79 args[j] = regs->ctx.DX[reg / 2].U1;
80 }
81 }
82
syscall_set_arguments(struct task_struct * task,struct pt_regs * regs,unsigned int i,unsigned int n,const unsigned long * args)83 static inline void syscall_set_arguments(struct task_struct *task,
84 struct pt_regs *regs,
85 unsigned int i, unsigned int n,
86 const unsigned long *args)
87 {
88 unsigned int reg;
89 BUG_ON(i + n > 6);
90
91 for (reg = 6 - i; i < (i + n); i++, reg--) {
92 if (reg % 2)
93 regs->ctx.DX[(reg + 1) / 2].U0 = args[i];
94 else
95 regs->ctx.DX[reg / 2].U1 = args[i];
96 }
97 }
98
99 #define NR_syscalls __NR_syscalls
100
101 /* generic syscall table */
102 extern const void *sys_call_table[];
103
104 #endif /* _ASM_METAG_SYSCALL_H */
105