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 <uapi/linux/audit.h>
17 #include <linux/sched.h>
18 #include <linux/thread_info.h>
19
20 /* ftrace syscalls requires exporting the sys_call_table */
21 #ifdef CONFIG_FTRACE_SYSCALLS
22 extern const unsigned long sys_call_table[];
23 #endif /* CONFIG_FTRACE_SYSCALLS */
24
syscall_get_nr(struct task_struct * task,struct pt_regs * regs)25 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
26 {
27 /*
28 * Note that we are returning an int here. That means 0xffffffff, ie.
29 * 32-bit negative 1, will be interpreted as -1 on a 64-bit kernel.
30 * This is important for seccomp so that compat tasks can set r0 = -1
31 * to reject the syscall.
32 */
33 return TRAP(regs) == 0xc00 ? regs->gpr[0] : -1;
34 }
35
syscall_rollback(struct task_struct * task,struct pt_regs * regs)36 static inline void syscall_rollback(struct task_struct *task,
37 struct pt_regs *regs)
38 {
39 regs->gpr[3] = regs->orig_gpr3;
40 }
41
syscall_get_return_value(struct task_struct * task,struct pt_regs * regs)42 static inline long syscall_get_return_value(struct task_struct *task,
43 struct pt_regs *regs)
44 {
45 return regs->gpr[3];
46 }
47
syscall_set_return_value(struct task_struct * task,struct pt_regs * regs,int error,long val)48 static inline void syscall_set_return_value(struct task_struct *task,
49 struct pt_regs *regs,
50 int error, long val)
51 {
52 /*
53 * In the general case it's not obvious that we must deal with CCR
54 * here, as the syscall exit path will also do that for us. However
55 * there are some places, eg. the signal code, which check ccr to
56 * decide if the value in r3 is actually an error.
57 */
58 if (error) {
59 regs->ccr |= 0x10000000L;
60 regs->gpr[3] = error;
61 } else {
62 regs->ccr &= ~0x10000000L;
63 regs->gpr[3] = val;
64 }
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 long val, mask = -1UL;
73
74 BUG_ON(i + n > 6);
75
76 #ifdef CONFIG_COMPAT
77 if (test_tsk_thread_flag(task, TIF_32BIT))
78 mask = 0xffffffff;
79 #endif
80 while (n--) {
81 if (n == 0 && i == 0)
82 val = regs->orig_gpr3;
83 else
84 val = regs->gpr[3 + i + n];
85
86 args[n] = val & mask;
87 }
88 }
89
syscall_set_arguments(struct task_struct * task,struct pt_regs * regs,unsigned int i,unsigned int n,const unsigned long * args)90 static inline void syscall_set_arguments(struct task_struct *task,
91 struct pt_regs *regs,
92 unsigned int i, unsigned int n,
93 const unsigned long *args)
94 {
95 BUG_ON(i + n > 6);
96 memcpy(®s->gpr[3 + i], args, n * sizeof(args[0]));
97
98 /* Also copy the first argument into orig_gpr3 */
99 if (i == 0 && n > 0)
100 regs->orig_gpr3 = args[0];
101 }
102
syscall_get_arch(void)103 static inline int syscall_get_arch(void)
104 {
105 int arch = is_32bit_task() ? AUDIT_ARCH_PPC : AUDIT_ARCH_PPC64;
106 #ifdef __LITTLE_ENDIAN__
107 arch |= __AUDIT_ARCH_LE;
108 #endif
109 return arch;
110 }
111 #endif /* _ASM_SYSCALL_H */
112
