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1 | /* |
2 | * Copyright 2011 Tilera Corporation. All Rights Reserved. |
3 | * |
4 | * This program is free software; you can redistribute it and/or |
5 | * modify it under the terms of the GNU General Public License |
6 | * as published by the Free Software Foundation, version 2. |
7 | * |
8 | * This program is distributed in the hope that it will be useful, but |
9 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
10 | * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or |
11 | * NON INFRINGEMENT. See the GNU General Public License for |
12 | * more details. |
13 | * |
14 | * Do memcpy(), but trap and return "n" when a load or store faults. |
15 | * |
16 | * Note: this idiom only works when memcpy() compiles to a leaf function. |
17 | * Here leaf function not only means it does not have calls, but also |
18 | * requires no stack operations (sp, stack frame pointer) and no |
19 | * use of callee-saved registers, else "jrp lr" will be incorrect since |
20 | * unwinding stack frame is bypassed. Since memcpy() is not complex so |
21 | * these conditions are satisfied here, but we need to be careful when |
22 | * modifying this file. This is not a clean solution but is the best |
23 | * one so far. |
24 | * |
25 | * Also note that we are capturing "n" from the containing scope here. |
26 | */ |
27 | |
28 | #define _ST(p, inst, v) \ |
29 | ({ \ |
30 | asm("1: " #inst " %0, %1;" \ |
31 | ".pushsection .coldtext.memcpy,\"ax\";" \ |
32 | "2: { move r0, %2; jrp lr };" \ |
33 | ".section __ex_table,\"a\";" \ |
34 | ".quad 1b, 2b;" \ |
35 | ".popsection" \ |
36 | : "=m" (*(p)) : "r" (v), "r" (n)); \ |
37 | }) |
38 | |
39 | #define _LD(p, inst) \ |
40 | ({ \ |
41 | unsigned long __v; \ |
42 | asm("1: " #inst " %0, %1;" \ |
43 | ".pushsection .coldtext.memcpy,\"ax\";" \ |
44 | "2: { move r0, %2; jrp lr };" \ |
45 | ".section __ex_table,\"a\";" \ |
46 | ".quad 1b, 2b;" \ |
47 | ".popsection" \ |
48 | : "=r" (__v) : "m" (*(p)), "r" (n)); \ |
49 | __v; \ |
50 | }) |
51 | |
52 | #define USERCOPY_FUNC __copy_to_user_inatomic |
53 | #define ST1(p, v) _ST((p), st1, (v)) |
54 | #define ST2(p, v) _ST((p), st2, (v)) |
55 | #define ST4(p, v) _ST((p), st4, (v)) |
56 | #define ST8(p, v) _ST((p), st, (v)) |
57 | #define LD1 LD |
58 | #define LD2 LD |
59 | #define LD4 LD |
60 | #define LD8 LD |
61 | #include "memcpy_64.c" |
62 | |
63 | #define USERCOPY_FUNC __copy_from_user_inatomic |
64 | #define ST1 ST |
65 | #define ST2 ST |
66 | #define ST4 ST |
67 | #define ST8 ST |
68 | #define LD1(p) _LD((p), ld1u) |
69 | #define LD2(p) _LD((p), ld2u) |
70 | #define LD4(p) _LD((p), ld4u) |
71 | #define LD8(p) _LD((p), ld) |
72 | #include "memcpy_64.c" |
73 | |
74 | #define USERCOPY_FUNC __copy_in_user_inatomic |
75 | #define ST1(p, v) _ST((p), st1, (v)) |
76 | #define ST2(p, v) _ST((p), st2, (v)) |
77 | #define ST4(p, v) _ST((p), st4, (v)) |
78 | #define ST8(p, v) _ST((p), st, (v)) |
79 | #define LD1(p) _LD((p), ld1u) |
80 | #define LD2(p) _LD((p), ld2u) |
81 | #define LD4(p) _LD((p), ld4u) |
82 | #define LD8(p) _LD((p), ld) |
83 | #include "memcpy_64.c" |
84 | |
85 | unsigned long __copy_from_user_zeroing(void *to, const void __user *from, |
86 | unsigned long n) |
87 | { |
88 | unsigned long rc = __copy_from_user_inatomic(to, from, n); |
89 | if (unlikely(rc)) |
90 | memset(to + n - rc, 0, rc); |
91 | return rc; |
92 | } |
93 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
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v3.9