1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
|
/*
* User address space access functions.
*
* Copyright 1997 Andi Kleen <ak@muc.de>
* Copyright 1997 Linus Torvalds
* Copyright 2002 Andi Kleen <ak@suse.de>
*/
#include <linux/export.h>
#include <linux/uaccess.h>
#include <linux/highmem.h>
/*
* Zero Userspace
*/
unsigned long __clear_user(void __user *addr, unsigned long size)
{
long __d0;
might_fault();
/* no memory constraint because it doesn't change any memory gcc knows
about */
stac();
asm volatile(
" testq %[size8],%[size8]\n"
" jz 4f\n"
"0: movq %[zero],(%[dst])\n"
" addq %[eight],%[dst]\n"
" decl %%ecx ; jnz 0b\n"
"4: movq %[size1],%%rcx\n"
" testl %%ecx,%%ecx\n"
" jz 2f\n"
"1: movb %b[zero],(%[dst])\n"
" incq %[dst]\n"
" decl %%ecx ; jnz 1b\n"
"2:\n"
".section .fixup,\"ax\"\n"
"3: lea 0(%[size1],%[size8],8),%[size8]\n"
" jmp 2b\n"
".previous\n"
_ASM_EXTABLE(0b,3b)
_ASM_EXTABLE(1b,2b)
: [size8] "=&c"(size), [dst] "=&D" (__d0)
: [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr),
[zero] "r" (0UL), [eight] "r" (8UL));
clac();
return size;
}
EXPORT_SYMBOL(__clear_user);
unsigned long clear_user(void __user *to, unsigned long n)
{
if (access_ok(VERIFY_WRITE, to, n))
return __clear_user(to, n);
return n;
}
EXPORT_SYMBOL(clear_user);
/*
* Try to copy last bytes and clear the rest if needed.
* Since protection fault in copy_from/to_user is not a normal situation,
* it is not necessary to optimize tail handling.
*/
__visible unsigned long
copy_user_handle_tail(char *to, char *from, unsigned len)
{
for (; len; --len, to++) {
char c;
if (__get_user_nocheck(c, from++, sizeof(char)))
break;
if (__put_user_nocheck(c, to, sizeof(char)))
break;
}
clac();
return len;
}
#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
/**
* clean_cache_range - write back a cache range with CLWB
* @vaddr: virtual start address
* @size: number of bytes to write back
*
* Write back a cache range using the CLWB (cache line write back)
* instruction. Note that @size is internally rounded up to be cache
* line size aligned.
*/
static void clean_cache_range(void *addr, size_t size)
{
u16 x86_clflush_size = boot_cpu_data.x86_clflush_size;
unsigned long clflush_mask = x86_clflush_size - 1;
void *vend = addr + size;
void *p;
for (p = (void *)((unsigned long)addr & ~clflush_mask);
p < vend; p += x86_clflush_size)
clwb(p);
}
long __copy_user_flushcache(void *dst, const void __user *src, unsigned size)
{
unsigned long flushed, dest = (unsigned long) dst;
long rc = __copy_user_nocache(dst, src, size, 0);
/*
* __copy_user_nocache() uses non-temporal stores for the bulk
* of the transfer, but we need to manually flush if the
* transfer is unaligned. A cached memory copy is used when
* destination or size is not naturally aligned. That is:
* - Require 8-byte alignment when size is 8 bytes or larger.
* - Require 4-byte alignment when size is 4 bytes.
*/
if (size < 8) {
if (!IS_ALIGNED(dest, 4) || size != 4)
clean_cache_range(dst, 1);
} else {
if (!IS_ALIGNED(dest, 8)) {
dest = ALIGN(dest, boot_cpu_data.x86_clflush_size);
clean_cache_range(dst, 1);
}
flushed = dest - (unsigned long) dst;
if (size > flushed && !IS_ALIGNED(size - flushed, 8))
clean_cache_range(dst + size - 1, 1);
}
return rc;
}
void memcpy_flushcache(void *_dst, const void *_src, size_t size)
{
unsigned long dest = (unsigned long) _dst;
unsigned long source = (unsigned long) _src;
/* cache copy and flush to align dest */
if (!IS_ALIGNED(dest, 8)) {
unsigned len = min_t(unsigned, size, ALIGN(dest, 8) - dest);
memcpy((void *) dest, (void *) source, len);
clean_cache_range((void *) dest, len);
dest += len;
source += len;
size -= len;
if (!size)
return;
}
/* 4x8 movnti loop */
while (size >= 32) {
asm("movq (%0), %%r8\n"
"movq 8(%0), %%r9\n"
"movq 16(%0), %%r10\n"
"movq 24(%0), %%r11\n"
"movnti %%r8, (%1)\n"
"movnti %%r9, 8(%1)\n"
"movnti %%r10, 16(%1)\n"
"movnti %%r11, 24(%1)\n"
:: "r" (source), "r" (dest)
: "memory", "r8", "r9", "r10", "r11");
dest += 32;
source += 32;
size -= 32;
}
/* 1x8 movnti loop */
while (size >= 8) {
asm("movq (%0), %%r8\n"
"movnti %%r8, (%1)\n"
:: "r" (source), "r" (dest)
: "memory", "r8");
dest += 8;
source += 8;
size -= 8;
}
/* 1x4 movnti loop */
while (size >= 4) {
asm("movl (%0), %%r8d\n"
"movnti %%r8d, (%1)\n"
:: "r" (source), "r" (dest)
: "memory", "r8");
dest += 4;
source += 4;
size -= 4;
}
/* cache copy for remaining bytes */
if (size) {
memcpy((void *) dest, (void *) source, size);
clean_cache_range((void *) dest, size);
}
}
EXPORT_SYMBOL_GPL(memcpy_flushcache);
void memcpy_page_flushcache(char *to, struct page *page, size_t offset,
size_t len)
{
char *from = kmap_atomic(page);
memcpy_flushcache(to, from + offset, len);
kunmap_atomic(from);
}
#endif
|
