1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * __put_user functions.
4 *
5 * (C) Copyright 2005 Linus Torvalds
6 * (C) Copyright 2005 Andi Kleen
7 * (C) Copyright 2008 Glauber Costa
8 *
9 * These functions have a non-standard call interface
10 * to make them more efficient, especially as they
11 * return an error value in addition to the "real"
12 * return value.
13 */
14#include <linux/export.h>
15#include <linux/linkage.h>
16#include <asm/thread_info.h>
17#include <asm/errno.h>
18#include <asm/asm.h>
19#include <asm/smap.h>
20
21/*
22 * __put_user_X
23 *
24 * Inputs: %eax[:%edx] contains the data
25 * %ecx contains the address
26 *
27 * Outputs: %ecx is error code (0 or -EFAULT)
28 *
29 * Clobbers: %ebx needed for task pointer
30 *
31 * These functions should not modify any other registers,
32 * as they get called from within inline assembly.
33 */
34
35.macro check_range size:req
36.if IS_ENABLED(CONFIG_X86_64)
37 mov %rcx, %rbx
38 sar $63, %rbx
39 or %rbx, %rcx
40.else
41 cmp $TASK_SIZE_MAX-\size+1, %ecx
42 jae .Lbad_put_user
43.endif
44.endm
45
46.text
47SYM_FUNC_START(__put_user_1)
48 check_range size=1
49 ASM_STAC
501: movb %al,(%_ASM_CX)
51 xor %ecx,%ecx
52 ASM_CLAC
53 RET
54SYM_FUNC_END(__put_user_1)
55EXPORT_SYMBOL(__put_user_1)
56
57SYM_FUNC_START(__put_user_nocheck_1)
58 ASM_STAC
592: movb %al,(%_ASM_CX)
60 xor %ecx,%ecx
61 ASM_CLAC
62 RET
63SYM_FUNC_END(__put_user_nocheck_1)
64EXPORT_SYMBOL(__put_user_nocheck_1)
65
66SYM_FUNC_START(__put_user_2)
67 check_range size=2
68 ASM_STAC
693: movw %ax,(%_ASM_CX)
70 xor %ecx,%ecx
71 ASM_CLAC
72 RET
73SYM_FUNC_END(__put_user_2)
74EXPORT_SYMBOL(__put_user_2)
75
76SYM_FUNC_START(__put_user_nocheck_2)
77 ASM_STAC
784: movw %ax,(%_ASM_CX)
79 xor %ecx,%ecx
80 ASM_CLAC
81 RET
82SYM_FUNC_END(__put_user_nocheck_2)
83EXPORT_SYMBOL(__put_user_nocheck_2)
84
85SYM_FUNC_START(__put_user_4)
86 check_range size=4
87 ASM_STAC
885: movl %eax,(%_ASM_CX)
89 xor %ecx,%ecx
90 ASM_CLAC
91 RET
92SYM_FUNC_END(__put_user_4)
93EXPORT_SYMBOL(__put_user_4)
94
95SYM_FUNC_START(__put_user_nocheck_4)
96 ASM_STAC
976: movl %eax,(%_ASM_CX)
98 xor %ecx,%ecx
99 ASM_CLAC
100 RET
101SYM_FUNC_END(__put_user_nocheck_4)
102EXPORT_SYMBOL(__put_user_nocheck_4)
103
104SYM_FUNC_START(__put_user_8)
105 check_range size=8
106 ASM_STAC
1077: mov %_ASM_AX,(%_ASM_CX)
108#ifdef CONFIG_X86_32
1098: movl %edx,4(%_ASM_CX)
110#endif
111 xor %ecx,%ecx
112 ASM_CLAC
113 RET
114SYM_FUNC_END(__put_user_8)
115EXPORT_SYMBOL(__put_user_8)
116
117SYM_FUNC_START(__put_user_nocheck_8)
118 ASM_STAC
1199: mov %_ASM_AX,(%_ASM_CX)
120#ifdef CONFIG_X86_32
12110: movl %edx,4(%_ASM_CX)
122#endif
123 xor %ecx,%ecx
124 ASM_CLAC
125 RET
126SYM_FUNC_END(__put_user_nocheck_8)
127EXPORT_SYMBOL(__put_user_nocheck_8)
128
129SYM_CODE_START_LOCAL(__put_user_handle_exception)
130 ASM_CLAC
131.Lbad_put_user:
132 movl $-EFAULT,%ecx
133 RET
134SYM_CODE_END(__put_user_handle_exception)
135
136 _ASM_EXTABLE(1b, __put_user_handle_exception)
137 _ASM_EXTABLE(2b, __put_user_handle_exception)
138 _ASM_EXTABLE(3b, __put_user_handle_exception)
139 _ASM_EXTABLE(4b, __put_user_handle_exception)
140 _ASM_EXTABLE(5b, __put_user_handle_exception)
141 _ASM_EXTABLE(6b, __put_user_handle_exception)
142 _ASM_EXTABLE(7b, __put_user_handle_exception)
143 _ASM_EXTABLE(9b, __put_user_handle_exception)
144#ifdef CONFIG_X86_32
145 _ASM_EXTABLE(8b, __put_user_handle_exception)
146 _ASM_EXTABLE(10b, __put_user_handle_exception)
147#endif
148

source code of linux/arch/x86/lib/putuser.S