xref: /openbmc/linux/arch/mips/include/asm/syscall.h (revision 0edbfea5)
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 
107 	while (n--)
108 		ret |= mips_get_syscall_arg(args++, task, regs, i++);
109 
110 	/*
111 	 * No way to communicate an error because this is a void function.
112 	 */
113 #if 0
114 	return ret;
115 #endif
116 }
117 
118 extern const unsigned long sys_call_table[];
119 extern const unsigned long sys32_call_table[];
120 extern const unsigned long sysn32_call_table[];
121 
122 static inline int syscall_get_arch(void)
123 {
124 	int arch = AUDIT_ARCH_MIPS;
125 #ifdef CONFIG_64BIT
126 	if (!test_thread_flag(TIF_32BIT_REGS)) {
127 		arch |= __AUDIT_ARCH_64BIT;
128 		/* N32 sets only TIF_32BIT_ADDR */
129 		if (test_thread_flag(TIF_32BIT_ADDR))
130 			arch |= __AUDIT_ARCH_CONVENTION_MIPS64_N32;
131 	}
132 #endif
133 #if defined(__LITTLE_ENDIAN)
134 	arch |=  __AUDIT_ARCH_LE;
135 #endif
136 	return arch;
137 }
138 
139 #endif	/* __ASM_MIPS_SYSCALL_H */
140