1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * Access to user system call parameters and results
4 *
5 * Copyright (C) 2008 Red Hat, Inc. All rights reserved.
6 *
7 * See asm-generic/syscall.h for descriptions of what we must do here.
8 */
9
10 #ifndef _ASM_SYSCALL_H
11 #define _ASM_SYSCALL_H 1
12
13 #include <uapi/linux/audit.h>
14 #include <linux/sched.h>
15 #include <linux/thread_info.h>
16
17 /* ftrace syscalls requires exporting the sys_call_table */
18 extern const unsigned long sys_call_table[];
19 extern const unsigned long compat_sys_call_table[];
20
syscall_get_nr(struct task_struct * task,struct pt_regs * regs)21 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
22 {
23 /*
24 * Note that we are returning an int here. That means 0xffffffff, ie.
25 * 32-bit negative 1, will be interpreted as -1 on a 64-bit kernel.
26 * This is important for seccomp so that compat tasks can set r0 = -1
27 * to reject the syscall.
28 */
29 if (trap_is_syscall(regs))
30 return regs->gpr[0];
31 else
32 return -1;
33 }
34
syscall_rollback(struct task_struct * task,struct pt_regs * regs)35 static inline void syscall_rollback(struct task_struct *task,
36 struct pt_regs *regs)
37 {
38 regs->gpr[3] = regs->orig_gpr3;
39 }
40
syscall_get_error(struct task_struct * task,struct pt_regs * regs)41 static inline long syscall_get_error(struct task_struct *task,
42 struct pt_regs *regs)
43 {
44 if (trap_is_scv(regs)) {
45 unsigned long error = regs->gpr[3];
46
47 return IS_ERR_VALUE(error) ? error : 0;
48 } else {
49 /*
50 * If the system call failed,
51 * regs->gpr[3] contains a positive ERRORCODE.
52 */
53 return (regs->ccr & 0x10000000UL) ? -regs->gpr[3] : 0;
54 }
55 }
56
syscall_get_return_value(struct task_struct * task,struct pt_regs * regs)57 static inline long syscall_get_return_value(struct task_struct *task,
58 struct pt_regs *regs)
59 {
60 return regs->gpr[3];
61 }
62
syscall_set_return_value(struct task_struct * task,struct pt_regs * regs,int error,long val)63 static inline void syscall_set_return_value(struct task_struct *task,
64 struct pt_regs *regs,
65 int error, long val)
66 {
67 if (trap_is_scv(regs)) {
68 regs->gpr[3] = (long) error ?: val;
69 } else {
70 /*
71 * In the general case it's not obvious that we must deal with
72 * CCR here, as the syscall exit path will also do that for us.
73 * However there are some places, eg. the signal code, which
74 * check ccr to decide if the value in r3 is actually an error.
75 */
76 if (error) {
77 regs->ccr |= 0x10000000L;
78 regs->gpr[3] = error;
79 } else {
80 regs->ccr &= ~0x10000000L;
81 regs->gpr[3] = val;
82 }
83 }
84 }
85
syscall_get_arguments(struct task_struct * task,struct pt_regs * regs,unsigned long * args)86 static inline void syscall_get_arguments(struct task_struct *task,
87 struct pt_regs *regs,
88 unsigned long *args)
89 {
90 unsigned long val, mask = -1UL;
91 unsigned int n = 6;
92
93 #ifdef CONFIG_COMPAT
94 if (test_tsk_thread_flag(task, TIF_32BIT))
95 mask = 0xffffffff;
96 #endif
97 while (n--) {
98 if (n == 0)
99 val = regs->orig_gpr3;
100 else
101 val = regs->gpr[3 + n];
102
103 args[n] = val & mask;
104 }
105 }
106
syscall_set_arguments(struct task_struct * task,struct pt_regs * regs,const unsigned long * args)107 static inline void syscall_set_arguments(struct task_struct *task,
108 struct pt_regs *regs,
109 const unsigned long *args)
110 {
111 memcpy(®s->gpr[3], args, 6 * sizeof(args[0]));
112
113 /* Also copy the first argument into orig_gpr3 */
114 regs->orig_gpr3 = args[0];
115 }
116
syscall_get_arch(struct task_struct * task)117 static inline int syscall_get_arch(struct task_struct *task)
118 {
119 int arch;
120
121 if (IS_ENABLED(CONFIG_PPC64) && !test_tsk_thread_flag(task, TIF_32BIT))
122 arch = AUDIT_ARCH_PPC64;
123 else
124 arch = AUDIT_ARCH_PPC;
125
126 #ifdef __LITTLE_ENDIAN__
127 arch |= __AUDIT_ARCH_LE;
128 #endif
129 return arch;
130 }
131 #endif /* _ASM_SYSCALL_H */
132