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
119