Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * __get_user functions. | |
3 | * | |
4 | * (C) Copyright 1998 Linus Torvalds | |
5 | * | |
6 | * These functions have a non-standard call interface | |
7 | * to make them more efficient, especially as they | |
8 | * return an error value in addition to the "real" | |
9 | * return value. | |
10 | */ | |
00e065ea JB |
11 | #include <linux/linkage.h> |
12 | #include <asm/dwarf2.h> | |
1da177e4 LT |
13 | #include <asm/thread_info.h> |
14 | ||
15 | ||
16 | /* | |
17 | * __get_user_X | |
18 | * | |
19 | * Inputs: %eax contains the address | |
20 | * | |
21 | * Outputs: %eax is error code (0 or -EFAULT) | |
22 | * %edx contains zero-extended value | |
23 | * | |
24 | * These functions should not modify any other registers, | |
25 | * as they get called from within inline assembly. | |
26 | */ | |
27 | ||
28 | .text | |
00e065ea JB |
29 | ENTRY(__get_user_1) |
30 | CFI_STARTPROC | |
1da177e4 LT |
31 | GET_THREAD_INFO(%edx) |
32 | cmpl TI_addr_limit(%edx),%eax | |
33 | jae bad_get_user | |
34 | 1: movzbl (%eax),%edx | |
35 | xorl %eax,%eax | |
36 | ret | |
00e065ea JB |
37 | CFI_ENDPROC |
38 | ENDPROC(__get_user_1) | |
1da177e4 | 39 | |
00e065ea JB |
40 | ENTRY(__get_user_2) |
41 | CFI_STARTPROC | |
1da177e4 LT |
42 | addl $1,%eax |
43 | jc bad_get_user | |
44 | GET_THREAD_INFO(%edx) | |
45 | cmpl TI_addr_limit(%edx),%eax | |
46 | jae bad_get_user | |
47 | 2: movzwl -1(%eax),%edx | |
48 | xorl %eax,%eax | |
49 | ret | |
00e065ea JB |
50 | CFI_ENDPROC |
51 | ENDPROC(__get_user_2) | |
1da177e4 | 52 | |
00e065ea JB |
53 | ENTRY(__get_user_4) |
54 | CFI_STARTPROC | |
1da177e4 LT |
55 | addl $3,%eax |
56 | jc bad_get_user | |
57 | GET_THREAD_INFO(%edx) | |
58 | cmpl TI_addr_limit(%edx),%eax | |
59 | jae bad_get_user | |
60 | 3: movl -3(%eax),%edx | |
61 | xorl %eax,%eax | |
62 | ret | |
00e065ea JB |
63 | CFI_ENDPROC |
64 | ENDPROC(__get_user_4) | |
1da177e4 LT |
65 | |
66 | bad_get_user: | |
00e065ea | 67 | CFI_STARTPROC |
1da177e4 LT |
68 | xorl %edx,%edx |
69 | movl $-14,%eax | |
70 | ret | |
00e065ea JB |
71 | CFI_ENDPROC |
72 | END(bad_get_user) | |
1da177e4 LT |
73 | |
74 | .section __ex_table,"a" | |
75 | .long 1b,bad_get_user | |
76 | .long 2b,bad_get_user | |
77 | .long 3b,bad_get_user | |
78 | .previous |