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 #ifdef CONFIG_ARCH_HAS_SYSCALL_WRAPPER
18 typedef long (*syscall_fn)(const struct pt_regs *);
19 #else
20 typedef long (*syscall_fn)(unsigned long, unsigned long, unsigned long,
21 unsigned long, unsigned long, unsigned long);
22 #endif
23
24 /* ftrace syscalls requires exporting the sys_call_table */
25 extern const syscall_fn sys_call_table[];
26 extern const syscall_fn compat_sys_call_table[];
27
28 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
29 {
30 /*
31 * Note that we are returning an int here. That means 0xffffffff, ie.
32 * 32-bit negative 1, will be interpreted as -1 on a 64-bit kernel.
33 * This is important for seccomp so that compat tasks can set r0 = -1
34 * to reject the syscall.
35 */
36 if (trap_is_syscall(regs))
37 return regs->gpr[0];
38 else
39 return -1;
40 }
41
42 static inline void syscall_rollback(struct task_struct *task,
43 struct pt_regs *regs)
44 {
45 regs->gpr[3] = regs->orig_gpr3;
46 }
47
48 static inline long syscall_get_error(struct task_struct *task,
49 struct pt_regs *regs)
50 {
51 if (trap_is_scv(regs)) {
52 unsigned long error = regs->gpr[3];
53
54 return IS_ERR_VALUE(error) ? error : 0;
55 } else {
56 /*
57 * If the system call failed,
58 * regs->gpr[3] contains a positive ERRORCODE.
59 */
60 return (regs->ccr & 0x10000000UL) ? -regs->gpr[3] : 0;
61 }
62 }
63
64 static inline long syscall_get_return_value(struct task_struct *task,
65 struct pt_regs *regs)
66 {
67 return regs->gpr[3];
68 }
69
70 static inline void syscall_set_return_value(struct task_struct *task,
71 struct pt_regs *regs,
72 int error, long val)
73 {
74 if (trap_is_scv(regs)) {
75 regs->gpr[3] = (long) error ?: val;
76 } else {
77 /*
78 * In the general case it's not obvious that we must deal with
79 * CCR here, as the syscall exit path will also do that for us.
80 * However there are some places, eg. the signal code, which
81 * check ccr to decide if the value in r3 is actually an error.
82 */
83 if (error) {
84 regs->ccr |= 0x10000000L;
85 regs->gpr[3] = error;
86 } else {
87 regs->ccr &= ~0x10000000L;
88 regs->gpr[3] = val;
89 }
90 }
91 }
92
93 static inline void syscall_get_arguments(struct task_struct *task,
94 struct pt_regs *regs,
95 unsigned long *args)
96 {
97 unsigned long val, mask = -1UL;
98 unsigned int n = 6;
99
100 if (is_tsk_32bit_task(task))
101 mask = 0xffffffff;
102
103 while (n--) {
104 if (n == 0)
105 val = regs->orig_gpr3;
106 else
107 val = regs->gpr[3 + n];
108
109 args[n] = val & mask;
110 }
111 }
112
113 static inline int syscall_get_arch(struct task_struct *task)
114 {
115 if (is_tsk_32bit_task(task))
116 return AUDIT_ARCH_PPC;
117 else if (IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN))
118 return AUDIT_ARCH_PPC64LE;
119 else
120 return AUDIT_ARCH_PPC64;
121 }
122 #endif /* _ASM_SYSCALL_H */
123
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