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linux
1/*
2 * __put_user functions.
3 *
4 * (C) Copyright 2005 Linus Torvalds
5 * (C) Copyright 2005 Andi Kleen
6 * (C) Copyright 2008 Glauber Costa
7 *
8 * These functions have a non-standard call interface
9 * to make them more efficient, especially as they
10 * return an error value in addition to the "real"
11 * return value.
12 */
13#include <linux/linkage.h>
14#include <asm/thread_info.h>
15#include <asm/errno.h>
16#include <asm/asm.h>
17#include <asm/smap.h>
18#include <asm/export.h>
19
20
21/*
22 * __put_user_X
23 *
24 * Inputs: %eax[:%edx] contains the data
25 * %ecx contains the address
26 *
27 * Outputs: %eax is error code (0 or -EFAULT)
28 *
29 * These functions should not modify any other registers,
30 * as they get called from within inline assembly.
31 */
32
33#define ENTER mov PER_CPU_VAR(current_task), %_ASM_BX
34#define EXIT ASM_CLAC ; \
35 ret
36
37.text
38ENTRY(__put_user_1)
39 ENTER
40 cmp TASK_addr_limit(%_ASM_BX),%_ASM_CX
41 jae bad_put_user
42 ASM_STAC
431: movb %al,(%_ASM_CX)
44 xor %eax,%eax
45 EXIT
46ENDPROC(__put_user_1)
47EXPORT_SYMBOL(__put_user_1)
48
49ENTRY(__put_user_2)
50 ENTER
51 mov TASK_addr_limit(%_ASM_BX),%_ASM_BX
52 sub $1,%_ASM_BX
53 cmp %_ASM_BX,%_ASM_CX
54 jae bad_put_user
55 ASM_STAC
562: movw %ax,(%_ASM_CX)
57 xor %eax,%eax
58 EXIT
59ENDPROC(__put_user_2)
60EXPORT_SYMBOL(__put_user_2)
61
62ENTRY(__put_user_4)
63 ENTER
64 mov TASK_addr_limit(%_ASM_BX),%_ASM_BX
65 sub $3,%_ASM_BX
66 cmp %_ASM_BX,%_ASM_CX
67 jae bad_put_user
68 ASM_STAC
693: movl %eax,(%_ASM_CX)
70 xor %eax,%eax
71 EXIT
72ENDPROC(__put_user_4)
73EXPORT_SYMBOL(__put_user_4)
74
75ENTRY(__put_user_8)
76 ENTER
77 mov TASK_addr_limit(%_ASM_BX),%_ASM_BX
78 sub $7,%_ASM_BX
79 cmp %_ASM_BX,%_ASM_CX
80 jae bad_put_user
81 ASM_STAC
824: mov %_ASM_AX,(%_ASM_CX)
83#ifdef CONFIG_X86_32
845: movl %edx,4(%_ASM_CX)
85#endif
86 xor %eax,%eax
87 EXIT
88ENDPROC(__put_user_8)
89EXPORT_SYMBOL(__put_user_8)
90
91bad_put_user:
92 movl $-EFAULT,%eax
93 EXIT
94END(bad_put_user)
95
96 _ASM_EXTABLE(1b,bad_put_user)
97 _ASM_EXTABLE(2b,bad_put_user)
98 _ASM_EXTABLE(3b,bad_put_user)
99 _ASM_EXTABLE(4b,bad_put_user)
100#ifdef CONFIG_X86_32
101 _ASM_EXTABLE(5b,bad_put_user)
102#endif