Linux kernel mirror (for testing)
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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/linkage.h>
15#include <asm/thread_info.h>
16#include <asm/errno.h>
17#include <asm/asm.h>
18#include <asm/smap.h>
19#include <asm/export.h>
20
21
22/*
23 * __put_user_X
24 *
25 * Inputs: %eax[:%edx] contains the data
26 * %ecx contains the address
27 *
28 * Outputs: %ecx is error code (0 or -EFAULT)
29 *
30 * Clobbers: %ebx needed for task pointer
31 *
32 * These functions should not modify any other registers,
33 * as they get called from within inline assembly.
34 */
35
36#ifdef CONFIG_X86_5LEVEL
37#define LOAD_TASK_SIZE_MINUS_N(n) \
38 ALTERNATIVE __stringify(mov $((1 << 47) - 4096 - (n)),%rbx), \
39 __stringify(mov $((1 << 56) - 4096 - (n)),%rbx), X86_FEATURE_LA57
40#else
41#define LOAD_TASK_SIZE_MINUS_N(n) \
42 mov $(TASK_SIZE_MAX - (n)),%_ASM_BX
43#endif
44
45.text
46SYM_FUNC_START(__put_user_1)
47 LOAD_TASK_SIZE_MINUS_N(0)
48 cmp %_ASM_BX,%_ASM_CX
49 jae .Lbad_put_user
50SYM_INNER_LABEL(__put_user_nocheck_1, SYM_L_GLOBAL)
51 ENDBR
52 ASM_STAC
531: movb %al,(%_ASM_CX)
54 xor %ecx,%ecx
55 ASM_CLAC
56 RET
57SYM_FUNC_END(__put_user_1)
58EXPORT_SYMBOL(__put_user_1)
59EXPORT_SYMBOL(__put_user_nocheck_1)
60
61SYM_FUNC_START(__put_user_2)
62 LOAD_TASK_SIZE_MINUS_N(1)
63 cmp %_ASM_BX,%_ASM_CX
64 jae .Lbad_put_user
65SYM_INNER_LABEL(__put_user_nocheck_2, SYM_L_GLOBAL)
66 ENDBR
67 ASM_STAC
682: movw %ax,(%_ASM_CX)
69 xor %ecx,%ecx
70 ASM_CLAC
71 RET
72SYM_FUNC_END(__put_user_2)
73EXPORT_SYMBOL(__put_user_2)
74EXPORT_SYMBOL(__put_user_nocheck_2)
75
76SYM_FUNC_START(__put_user_4)
77 LOAD_TASK_SIZE_MINUS_N(3)
78 cmp %_ASM_BX,%_ASM_CX
79 jae .Lbad_put_user
80SYM_INNER_LABEL(__put_user_nocheck_4, SYM_L_GLOBAL)
81 ENDBR
82 ASM_STAC
833: movl %eax,(%_ASM_CX)
84 xor %ecx,%ecx
85 ASM_CLAC
86 RET
87SYM_FUNC_END(__put_user_4)
88EXPORT_SYMBOL(__put_user_4)
89EXPORT_SYMBOL(__put_user_nocheck_4)
90
91SYM_FUNC_START(__put_user_8)
92 LOAD_TASK_SIZE_MINUS_N(7)
93 cmp %_ASM_BX,%_ASM_CX
94 jae .Lbad_put_user
95SYM_INNER_LABEL(__put_user_nocheck_8, SYM_L_GLOBAL)
96 ENDBR
97 ASM_STAC
984: mov %_ASM_AX,(%_ASM_CX)
99#ifdef CONFIG_X86_32
1005: movl %edx,4(%_ASM_CX)
101#endif
102 xor %ecx,%ecx
103 ASM_CLAC
104 RET
105SYM_FUNC_END(__put_user_8)
106EXPORT_SYMBOL(__put_user_8)
107EXPORT_SYMBOL(__put_user_nocheck_8)
108
109SYM_CODE_START_LOCAL(.Lbad_put_user_clac)
110 ASM_CLAC
111.Lbad_put_user:
112 movl $-EFAULT,%ecx
113 RET
114SYM_CODE_END(.Lbad_put_user_clac)
115
116 _ASM_EXTABLE_UA(1b, .Lbad_put_user_clac)
117 _ASM_EXTABLE_UA(2b, .Lbad_put_user_clac)
118 _ASM_EXTABLE_UA(3b, .Lbad_put_user_clac)
119 _ASM_EXTABLE_UA(4b, .Lbad_put_user_clac)
120#ifdef CONFIG_X86_32
121 _ASM_EXTABLE_UA(5b, .Lbad_put_user_clac)
122#endif