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1932fbe3 GH |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | // Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved. | |
3 | // Copyright (C) 2005-2017 Andes Technology Corporation | |
4 | ||
5 | #ifndef _ASM_NDS32_SYSCALL_H | |
6 | #define _ASM_NDS32_SYSCALL_H 1 | |
7 | ||
8 | #include <linux/err.h> | |
9 | struct task_struct; | |
10 | struct pt_regs; | |
11 | ||
12 | /** | |
13 | * syscall_get_nr - find what system call a task is executing | |
14 | * @task: task of interest, must be blocked | |
15 | * @regs: task_pt_regs() of @task | |
16 | * | |
17 | * If @task is executing a system call or is at system call | |
18 | * tracing about to attempt one, returns the system call number. | |
19 | * If @task is not executing a system call, i.e. it's blocked | |
20 | * inside the kernel for a fault or signal, returns -1. | |
21 | * | |
22 | * Note this returns int even on 64-bit machines. Only 32 bits of | |
23 | * system call number can be meaningful. If the actual arch value | |
24 | * is 64 bits, this truncates to 32 bits so 0xffffffff means -1. | |
25 | * | |
26 | * It's only valid to call this when @task is known to be blocked. | |
27 | */ | |
28 | int syscall_get_nr(struct task_struct *task, struct pt_regs *regs) | |
29 | { | |
30 | return regs->syscallno; | |
31 | } | |
32 | ||
33 | /** | |
34 | * syscall_rollback - roll back registers after an aborted system call | |
35 | * @task: task of interest, must be in system call exit tracing | |
36 | * @regs: task_pt_regs() of @task | |
37 | * | |
38 | * It's only valid to call this when @task is stopped for system | |
39 | * call exit tracing (due to TIF_SYSCALL_TRACE or TIF_SYSCALL_AUDIT), | |
40 | * after tracehook_report_syscall_entry() returned nonzero to prevent | |
41 | * the system call from taking place. | |
42 | * | |
43 | * This rolls back the register state in @regs so it's as if the | |
44 | * system call instruction was a no-op. The registers containing | |
45 | * the system call number and arguments are as they were before the | |
46 | * system call instruction. This may not be the same as what the | |
47 | * register state looked like at system call entry tracing. | |
48 | */ | |
49 | void syscall_rollback(struct task_struct *task, struct pt_regs *regs) | |
50 | { | |
51 | regs->uregs[0] = regs->orig_r0; | |
52 | } | |
53 | ||
54 | /** | |
55 | * syscall_get_error - check result of traced system call | |
56 | * @task: task of interest, must be blocked | |
57 | * @regs: task_pt_regs() of @task | |
58 | * | |
59 | * Returns 0 if the system call succeeded, or -ERRORCODE if it failed. | |
60 | * | |
61 | * It's only valid to call this when @task is stopped for tracing on exit | |
62 | * from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. | |
63 | */ | |
64 | long syscall_get_error(struct task_struct *task, struct pt_regs *regs) | |
65 | { | |
66 | unsigned long error = regs->uregs[0]; | |
67 | return IS_ERR_VALUE(error) ? error : 0; | |
68 | } | |
69 | ||
70 | /** | |
71 | * syscall_get_return_value - get the return value of a traced system call | |
72 | * @task: task of interest, must be blocked | |
73 | * @regs: task_pt_regs() of @task | |
74 | * | |
75 | * Returns the return value of the successful system call. | |
76 | * This value is meaningless if syscall_get_error() returned nonzero. | |
77 | * | |
78 | * It's only valid to call this when @task is stopped for tracing on exit | |
79 | * from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. | |
80 | */ | |
81 | long syscall_get_return_value(struct task_struct *task, struct pt_regs *regs) | |
82 | { | |
83 | return regs->uregs[0]; | |
84 | } | |
85 | ||
86 | /** | |
87 | * syscall_set_return_value - change the return value of a traced system call | |
88 | * @task: task of interest, must be blocked | |
89 | * @regs: task_pt_regs() of @task | |
90 | * @error: negative error code, or zero to indicate success | |
91 | * @val: user return value if @error is zero | |
92 | * | |
93 | * This changes the results of the system call that user mode will see. | |
94 | * If @error is zero, the user sees a successful system call with a | |
95 | * return value of @val. If @error is nonzero, it's a negated errno | |
96 | * code; the user sees a failed system call with this errno code. | |
97 | * | |
98 | * It's only valid to call this when @task is stopped for tracing on exit | |
99 | * from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. | |
100 | */ | |
101 | void syscall_set_return_value(struct task_struct *task, struct pt_regs *regs, | |
102 | int error, long val) | |
103 | { | |
104 | regs->uregs[0] = (long)error ? error : val; | |
105 | } | |
106 | ||
107 | /** | |
108 | * syscall_get_arguments - extract system call parameter values | |
109 | * @task: task of interest, must be blocked | |
110 | * @regs: task_pt_regs() of @task | |
1932fbe3 GH |
111 | * @args: array filled with argument values |
112 | * | |
b35f549d SRRH |
113 | * Fetches 6 arguments to the system call (from 0 through 5). The first |
114 | * argument is stored in @args[0], and so on. | |
1932fbe3 GH |
115 | * |
116 | * It's only valid to call this when @task is stopped for tracing on | |
117 | * entry to a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. | |
1932fbe3 GH |
118 | */ |
119 | #define SYSCALL_MAX_ARGS 6 | |
120 | void syscall_get_arguments(struct task_struct *task, struct pt_regs *regs, | |
b35f549d | 121 | unsigned long *args) |
1932fbe3 | 122 | { |
b35f549d SRRH |
123 | args[0] = regs->orig_r0; |
124 | args++; | |
125 | memcpy(args, ®s->uregs[0] + 1, 5 * sizeof(args[0])); | |
1932fbe3 GH |
126 | } |
127 | ||
128 | /** | |
129 | * syscall_set_arguments - change system call parameter value | |
130 | * @task: task of interest, must be in system call entry tracing | |
131 | * @regs: task_pt_regs() of @task | |
1932fbe3 GH |
132 | * @args: array of argument values to store |
133 | * | |
32d92586 SRV |
134 | * Changes 6 arguments to the system call. The first argument gets value |
135 | * @args[0], and so on. | |
1932fbe3 GH |
136 | * |
137 | * It's only valid to call this when @task is stopped for tracing on | |
138 | * entry to a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. | |
1932fbe3 GH |
139 | */ |
140 | void syscall_set_arguments(struct task_struct *task, struct pt_regs *regs, | |
1932fbe3 GH |
141 | const unsigned long *args) |
142 | { | |
32d92586 SRV |
143 | regs->orig_r0 = args[0]; |
144 | args++; | |
1932fbe3 | 145 | |
32d92586 | 146 | memcpy(®s->uregs[0] + 1, args, 5 * sizeof(args[0])); |
1932fbe3 GH |
147 | } |
148 | #endif /* _ASM_NDS32_SYSCALL_H */ |