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 ASM_STAC
521: movb %al,(%_ASM_CX)
53 xor %ecx,%ecx
54 ASM_CLAC
55 RET
56SYM_FUNC_END(__put_user_1)
57EXPORT_SYMBOL(__put_user_1)
58EXPORT_SYMBOL(__put_user_nocheck_1)
59
60SYM_FUNC_START(__put_user_2)
61 LOAD_TASK_SIZE_MINUS_N(1)
62 cmp %_ASM_BX,%_ASM_CX
63 jae .Lbad_put_user
64SYM_INNER_LABEL(__put_user_nocheck_2, SYM_L_GLOBAL)
65 ASM_STAC
662: movw %ax,(%_ASM_CX)
67 xor %ecx,%ecx
68 ASM_CLAC
69 RET
70SYM_FUNC_END(__put_user_2)
71EXPORT_SYMBOL(__put_user_2)
72EXPORT_SYMBOL(__put_user_nocheck_2)
73
74SYM_FUNC_START(__put_user_4)
75 LOAD_TASK_SIZE_MINUS_N(3)
76 cmp %_ASM_BX,%_ASM_CX
77 jae .Lbad_put_user
78SYM_INNER_LABEL(__put_user_nocheck_4, SYM_L_GLOBAL)
79 ASM_STAC
803: movl %eax,(%_ASM_CX)
81 xor %ecx,%ecx
82 ASM_CLAC
83 RET
84SYM_FUNC_END(__put_user_4)
85EXPORT_SYMBOL(__put_user_4)
86EXPORT_SYMBOL(__put_user_nocheck_4)
87
88SYM_FUNC_START(__put_user_8)
89 LOAD_TASK_SIZE_MINUS_N(7)
90 cmp %_ASM_BX,%_ASM_CX
91 jae .Lbad_put_user
92SYM_INNER_LABEL(__put_user_nocheck_8, SYM_L_GLOBAL)
93 ASM_STAC
944: mov %_ASM_AX,(%_ASM_CX)
95#ifdef CONFIG_X86_32
965: movl %edx,4(%_ASM_CX)
97#endif
98 xor %ecx,%ecx
99 ASM_CLAC
100 RET
101SYM_FUNC_END(__put_user_8)
102EXPORT_SYMBOL(__put_user_8)
103EXPORT_SYMBOL(__put_user_nocheck_8)
104
105SYM_CODE_START_LOCAL(.Lbad_put_user_clac)
106 ASM_CLAC
107.Lbad_put_user:
108 movl $-EFAULT,%ecx
109 RET
110SYM_CODE_END(.Lbad_put_user_clac)
111
112 _ASM_EXTABLE_UA(1b, .Lbad_put_user_clac)
113 _ASM_EXTABLE_UA(2b, .Lbad_put_user_clac)
114 _ASM_EXTABLE_UA(3b, .Lbad_put_user_clac)
115 _ASM_EXTABLE_UA(4b, .Lbad_put_user_clac)
116#ifdef CONFIG_X86_32
117 _ASM_EXTABLE_UA(5b, .Lbad_put_user_clac)
118#endif