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1/*
2 * User address space access functions.
3 *
4 * Copyright 1997 Andi Kleen <ak@muc.de>
5 * Copyright 1997 Linus Torvalds
6 * Copyright 2002 Andi Kleen <ak@suse.de>
7 */
8#include <linux/module.h>
9#include <asm/uaccess.h>
10
11/*
12 * Zero Userspace
13 */
14
15unsigned long __clear_user(void __user *addr, unsigned long size)
16{
17 long __d0;
18 might_fault();
19 /* no memory constraint because it doesn't change any memory gcc knows
20 about */
21 stac();
22 asm volatile(
23 " testq %[size8],%[size8]\n"
24 " jz 4f\n"
25 "0: movq %[zero],(%[dst])\n"
26 " addq %[eight],%[dst]\n"
27 " decl %%ecx ; jnz 0b\n"
28 "4: movq %[size1],%%rcx\n"
29 " testl %%ecx,%%ecx\n"
30 " jz 2f\n"
31 "1: movb %b[zero],(%[dst])\n"
32 " incq %[dst]\n"
33 " decl %%ecx ; jnz 1b\n"
34 "2:\n"
35 ".section .fixup,\"ax\"\n"
36 "3: lea 0(%[size1],%[size8],8),%[size8]\n"
37 " jmp 2b\n"
38 ".previous\n"
39 _ASM_EXTABLE(0b,3b)
40 _ASM_EXTABLE(1b,2b)
41 : [size8] "=&c"(size), [dst] "=&D" (__d0)
42 : [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr),
43 [zero] "r" (0UL), [eight] "r" (8UL));
44 clac();
45 return size;
46}
47EXPORT_SYMBOL(__clear_user);
48
49unsigned long clear_user(void __user *to, unsigned long n)
50{
51 if (access_ok(VERIFY_WRITE, to, n))
52 return __clear_user(to, n);
53 return n;
54}
55EXPORT_SYMBOL(clear_user);
56
57unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len)
58{
59 if (access_ok(VERIFY_WRITE, to, len) && access_ok(VERIFY_READ, from, len)) {
60 return copy_user_generic((__force void *)to, (__force void *)from, len);
61 }
62 return len;
63}
64EXPORT_SYMBOL(copy_in_user);
65
66/*
67 * Try to copy last bytes and clear the rest if needed.
68 * Since protection fault in copy_from/to_user is not a normal situation,
69 * it is not necessary to optimize tail handling.
70 */
71__visible unsigned long
72copy_user_handle_tail(char *to, char *from, unsigned len, unsigned zerorest)
73{
74 char c;
75 unsigned zero_len;
76
77 for (; len; --len, to++) {
78 if (__get_user_nocheck(c, from++, sizeof(char)))
79 break;
80 if (__put_user_nocheck(c, to, sizeof(char)))
81 break;
82 }
83
84 for (c = 0, zero_len = len; zerorest && zero_len; --zero_len)
85 if (__put_user_nocheck(c, to++, sizeof(char)))
86 break;
87 clac();
88 return len;
89}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * User address space access functions.
4 *
5 * Copyright 1997 Andi Kleen <ak@muc.de>
6 * Copyright 1997 Linus Torvalds
7 * Copyright 2002 Andi Kleen <ak@suse.de>
8 */
9#include <linux/export.h>
10#include <linux/uaccess.h>
11#include <linux/highmem.h>
12
13/*
14 * Zero Userspace
15 */
16
17unsigned long __clear_user(void __user *addr, unsigned long size)
18{
19 long __d0;
20 might_fault();
21 /* no memory constraint because it doesn't change any memory gcc knows
22 about */
23 stac();
24 asm volatile(
25 " testq %[size8],%[size8]\n"
26 " jz 4f\n"
27 " .align 16\n"
28 "0: movq $0,(%[dst])\n"
29 " addq $8,%[dst]\n"
30 " decl %%ecx ; jnz 0b\n"
31 "4: movq %[size1],%%rcx\n"
32 " testl %%ecx,%%ecx\n"
33 " jz 2f\n"
34 "1: movb $0,(%[dst])\n"
35 " incq %[dst]\n"
36 " decl %%ecx ; jnz 1b\n"
37 "2:\n"
38 ".section .fixup,\"ax\"\n"
39 "3: lea 0(%[size1],%[size8],8),%[size8]\n"
40 " jmp 2b\n"
41 ".previous\n"
42 _ASM_EXTABLE_UA(0b, 3b)
43 _ASM_EXTABLE_UA(1b, 2b)
44 : [size8] "=&c"(size), [dst] "=&D" (__d0)
45 : [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr));
46 clac();
47 return size;
48}
49EXPORT_SYMBOL(__clear_user);
50
51unsigned long clear_user(void __user *to, unsigned long n)
52{
53 if (access_ok(to, n))
54 return __clear_user(to, n);
55 return n;
56}
57EXPORT_SYMBOL(clear_user);
58
59/*
60 * Similar to copy_user_handle_tail, probe for the write fault point,
61 * but reuse __memcpy_mcsafe in case a new read error is encountered.
62 * clac() is handled in _copy_to_iter_mcsafe().
63 */
64__visible notrace unsigned long
65mcsafe_handle_tail(char *to, char *from, unsigned len)
66{
67 for (; len; --len, to++, from++) {
68 /*
69 * Call the assembly routine back directly since
70 * memcpy_mcsafe() may silently fallback to memcpy.
71 */
72 unsigned long rem = __memcpy_mcsafe(to, from, 1);
73
74 if (rem)
75 break;
76 }
77 return len;
78}
79
80#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
81/**
82 * clean_cache_range - write back a cache range with CLWB
83 * @vaddr: virtual start address
84 * @size: number of bytes to write back
85 *
86 * Write back a cache range using the CLWB (cache line write back)
87 * instruction. Note that @size is internally rounded up to be cache
88 * line size aligned.
89 */
90static void clean_cache_range(void *addr, size_t size)
91{
92 u16 x86_clflush_size = boot_cpu_data.x86_clflush_size;
93 unsigned long clflush_mask = x86_clflush_size - 1;
94 void *vend = addr + size;
95 void *p;
96
97 for (p = (void *)((unsigned long)addr & ~clflush_mask);
98 p < vend; p += x86_clflush_size)
99 clwb(p);
100}
101
102void arch_wb_cache_pmem(void *addr, size_t size)
103{
104 clean_cache_range(addr, size);
105}
106EXPORT_SYMBOL_GPL(arch_wb_cache_pmem);
107
108long __copy_user_flushcache(void *dst, const void __user *src, unsigned size)
109{
110 unsigned long flushed, dest = (unsigned long) dst;
111 long rc = __copy_user_nocache(dst, src, size, 0);
112
113 /*
114 * __copy_user_nocache() uses non-temporal stores for the bulk
115 * of the transfer, but we need to manually flush if the
116 * transfer is unaligned. A cached memory copy is used when
117 * destination or size is not naturally aligned. That is:
118 * - Require 8-byte alignment when size is 8 bytes or larger.
119 * - Require 4-byte alignment when size is 4 bytes.
120 */
121 if (size < 8) {
122 if (!IS_ALIGNED(dest, 4) || size != 4)
123 clean_cache_range(dst, size);
124 } else {
125 if (!IS_ALIGNED(dest, 8)) {
126 dest = ALIGN(dest, boot_cpu_data.x86_clflush_size);
127 clean_cache_range(dst, 1);
128 }
129
130 flushed = dest - (unsigned long) dst;
131 if (size > flushed && !IS_ALIGNED(size - flushed, 8))
132 clean_cache_range(dst + size - 1, 1);
133 }
134
135 return rc;
136}
137
138void __memcpy_flushcache(void *_dst, const void *_src, size_t size)
139{
140 unsigned long dest = (unsigned long) _dst;
141 unsigned long source = (unsigned long) _src;
142
143 /* cache copy and flush to align dest */
144 if (!IS_ALIGNED(dest, 8)) {
145 unsigned len = min_t(unsigned, size, ALIGN(dest, 8) - dest);
146
147 memcpy((void *) dest, (void *) source, len);
148 clean_cache_range((void *) dest, len);
149 dest += len;
150 source += len;
151 size -= len;
152 if (!size)
153 return;
154 }
155
156 /* 4x8 movnti loop */
157 while (size >= 32) {
158 asm("movq (%0), %%r8\n"
159 "movq 8(%0), %%r9\n"
160 "movq 16(%0), %%r10\n"
161 "movq 24(%0), %%r11\n"
162 "movnti %%r8, (%1)\n"
163 "movnti %%r9, 8(%1)\n"
164 "movnti %%r10, 16(%1)\n"
165 "movnti %%r11, 24(%1)\n"
166 :: "r" (source), "r" (dest)
167 : "memory", "r8", "r9", "r10", "r11");
168 dest += 32;
169 source += 32;
170 size -= 32;
171 }
172
173 /* 1x8 movnti loop */
174 while (size >= 8) {
175 asm("movq (%0), %%r8\n"
176 "movnti %%r8, (%1)\n"
177 :: "r" (source), "r" (dest)
178 : "memory", "r8");
179 dest += 8;
180 source += 8;
181 size -= 8;
182 }
183
184 /* 1x4 movnti loop */
185 while (size >= 4) {
186 asm("movl (%0), %%r8d\n"
187 "movnti %%r8d, (%1)\n"
188 :: "r" (source), "r" (dest)
189 : "memory", "r8");
190 dest += 4;
191 source += 4;
192 size -= 4;
193 }
194
195 /* cache copy for remaining bytes */
196 if (size) {
197 memcpy((void *) dest, (void *) source, size);
198 clean_cache_range((void *) dest, size);
199 }
200}
201EXPORT_SYMBOL_GPL(__memcpy_flushcache);
202
203void memcpy_page_flushcache(char *to, struct page *page, size_t offset,
204 size_t len)
205{
206 char *from = kmap_atomic(page);
207
208 memcpy_flushcache(to, from + offset, len);
209 kunmap_atomic(from);
210}
211#endif