tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 * If "sp" is updated during memcpy, the "jrp lr" will be incorrect.
18 *
19 * Also note that we are capturing "n" from the containing scope here.
20 */
21
22#define _ST(p, inst, v) \
23 ({ \
24 asm("1: " #inst " %0, %1;" \
25 ".pushsection .coldtext.memcpy,\"ax\";" \
26 "2: { move r0, %2; jrp lr };" \
27 ".section __ex_table,\"a\";" \
28 ".quad 1b, 2b;" \
29 ".popsection" \
30 : "=m" (*(p)) : "r" (v), "r" (n)); \
31 })
32
33#define _LD(p, inst) \
34 ({ \
35 unsigned long __v; \
36 asm("1: " #inst " %0, %1;" \
37 ".pushsection .coldtext.memcpy,\"ax\";" \
38 "2: { move r0, %2; jrp lr };" \
39 ".section __ex_table,\"a\";" \
40 ".quad 1b, 2b;" \
41 ".popsection" \
42 : "=r" (__v) : "m" (*(p)), "r" (n)); \
43 __v; \
44 })
45
46#define USERCOPY_FUNC __copy_to_user_inatomic
47#define ST1(p, v) _ST((p), st1, (v))
48#define ST2(p, v) _ST((p), st2, (v))
49#define ST4(p, v) _ST((p), st4, (v))
50#define ST8(p, v) _ST((p), st, (v))
51#define LD1 LD
52#define LD2 LD
53#define LD4 LD
54#define LD8 LD
55#include "memcpy_64.c"
56
57#define USERCOPY_FUNC __copy_from_user_inatomic
58#define ST1 ST
59#define ST2 ST
60#define ST4 ST
61#define ST8 ST
62#define LD1(p) _LD((p), ld1u)
63#define LD2(p) _LD((p), ld2u)
64#define LD4(p) _LD((p), ld4u)
65#define LD8(p) _LD((p), ld)
66#include "memcpy_64.c"
67
68#define USERCOPY_FUNC __copy_in_user_inatomic
69#define ST1(p, v) _ST((p), st1, (v))
70#define ST2(p, v) _ST((p), st2, (v))
71#define ST4(p, v) _ST((p), st4, (v))
72#define ST8(p, v) _ST((p), st, (v))
73#define LD1(p) _LD((p), ld1u)
74#define LD2(p) _LD((p), ld2u)
75#define LD4(p) _LD((p), ld4u)
76#define LD8(p) _LD((p), ld)
77#include "memcpy_64.c"
78
79unsigned long __copy_from_user_zeroing(void *to, const void __user *from,
80 unsigned long n)
81{
82 unsigned long rc = __copy_from_user_inatomic(to, from, n);
83 if (unlikely(rc))
84 memset(to + n - rc, 0, rc);
85 return rc;
86}