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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 * Copy a null terminated string from userspace.
13 */
14
15#define __do_strncpy_from_user(dst,src,count,res) \
16do { \
17 long __d0, __d1, __d2; \
18 might_fault(); \
19 __asm__ __volatile__( \
20 " testq %1,%1\n" \
21 " jz 2f\n" \
22 "0: lodsb\n" \
23 " stosb\n" \
24 " testb %%al,%%al\n" \
25 " jz 1f\n" \
26 " decq %1\n" \
27 " jnz 0b\n" \
28 "1: subq %1,%0\n" \
29 "2:\n" \
30 ".section .fixup,\"ax\"\n" \
31 "3: movq %5,%0\n" \
32 " jmp 2b\n" \
33 ".previous\n" \
34 _ASM_EXTABLE(0b,3b) \
35 : "=&r"(res), "=&c"(count), "=&a" (__d0), "=&S" (__d1), \
36 "=&D" (__d2) \
37 : "i"(-EFAULT), "0"(count), "1"(count), "3"(src), "4"(dst) \
38 : "memory"); \
39} while (0)
40
41long
42__strncpy_from_user(char *dst, const char __user *src, long count)
43{
44 long res;
45 __do_strncpy_from_user(dst, src, count, res);
46 return res;
47}
48EXPORT_SYMBOL(__strncpy_from_user);
49
50long
51strncpy_from_user(char *dst, const char __user *src, long count)
52{
53 long res = -EFAULT;
54 if (access_ok(VERIFY_READ, src, 1))
55 return __strncpy_from_user(dst, src, count);
56 return res;
57}
58EXPORT_SYMBOL(strncpy_from_user);
59
60/*
61 * Zero Userspace
62 */
63
64unsigned long __clear_user(void __user *addr, unsigned long size)
65{
66 long __d0;
67 might_fault();
68 /* no memory constraint because it doesn't change any memory gcc knows
69 about */
70 asm volatile(
71 " testq %[size8],%[size8]\n"
72 " jz 4f\n"
73 "0: movq %[zero],(%[dst])\n"
74 " addq %[eight],%[dst]\n"
75 " decl %%ecx ; jnz 0b\n"
76 "4: movq %[size1],%%rcx\n"
77 " testl %%ecx,%%ecx\n"
78 " jz 2f\n"
79 "1: movb %b[zero],(%[dst])\n"
80 " incq %[dst]\n"
81 " decl %%ecx ; jnz 1b\n"
82 "2:\n"
83 ".section .fixup,\"ax\"\n"
84 "3: lea 0(%[size1],%[size8],8),%[size8]\n"
85 " jmp 2b\n"
86 ".previous\n"
87 _ASM_EXTABLE(0b,3b)
88 _ASM_EXTABLE(1b,2b)
89 : [size8] "=&c"(size), [dst] "=&D" (__d0)
90 : [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr),
91 [zero] "r" (0UL), [eight] "r" (8UL));
92 return size;
93}
94EXPORT_SYMBOL(__clear_user);
95
96unsigned long clear_user(void __user *to, unsigned long n)
97{
98 if (access_ok(VERIFY_WRITE, to, n))
99 return __clear_user(to, n);
100 return n;
101}
102EXPORT_SYMBOL(clear_user);
103
104/*
105 * Return the size of a string (including the ending 0)
106 *
107 * Return 0 on exception, a value greater than N if too long
108 */
109
110long __strnlen_user(const char __user *s, long n)
111{
112 long res = 0;
113 char c;
114
115 while (1) {
116 if (res>n)
117 return n+1;
118 if (__get_user(c, s))
119 return 0;
120 if (!c)
121 return res+1;
122 res++;
123 s++;
124 }
125}
126EXPORT_SYMBOL(__strnlen_user);
127
128long strnlen_user(const char __user *s, long n)
129{
130 if (!access_ok(VERIFY_READ, s, 1))
131 return 0;
132 return __strnlen_user(s, n);
133}
134EXPORT_SYMBOL(strnlen_user);
135
136long strlen_user(const char __user *s)
137{
138 long res = 0;
139 char c;
140
141 for (;;) {
142 if (get_user(c, s))
143 return 0;
144 if (!c)
145 return res+1;
146 res++;
147 s++;
148 }
149}
150EXPORT_SYMBOL(strlen_user);
151
152unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len)
153{
154 if (access_ok(VERIFY_WRITE, to, len) && access_ok(VERIFY_READ, from, len)) {
155 return copy_user_generic((__force void *)to, (__force void *)from, len);
156 }
157 return len;
158}
159EXPORT_SYMBOL(copy_in_user);
160
161/*
162 * Try to copy last bytes and clear the rest if needed.
163 * Since protection fault in copy_from/to_user is not a normal situation,
164 * it is not necessary to optimize tail handling.
165 */
166unsigned long
167copy_user_handle_tail(char *to, char *from, unsigned len, unsigned zerorest)
168{
169 char c;
170 unsigned zero_len;
171
172 for (; len; --len) {
173 if (__get_user_nocheck(c, from++, sizeof(char)))
174 break;
175 if (__put_user_nocheck(c, to++, sizeof(char)))
176 break;
177 }
178
179 for (c = 0, zero_len = len; zerorest && zero_len; --zero_len)
180 if (__put_user_nocheck(c, to++, sizeof(char)))
181 break;
182 return len;
183}
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#include <linux/libnvdimm.h>
13
14/*
15 * Zero Userspace
16 */
17
18#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
19/**
20 * clean_cache_range - write back a cache range with CLWB
21 * @vaddr: virtual start address
22 * @size: number of bytes to write back
23 *
24 * Write back a cache range using the CLWB (cache line write back)
25 * instruction. Note that @size is internally rounded up to be cache
26 * line size aligned.
27 */
28static void clean_cache_range(void *addr, size_t size)
29{
30 u16 x86_clflush_size = boot_cpu_data.x86_clflush_size;
31 unsigned long clflush_mask = x86_clflush_size - 1;
32 void *vend = addr + size;
33 void *p;
34
35 for (p = (void *)((unsigned long)addr & ~clflush_mask);
36 p < vend; p += x86_clflush_size)
37 clwb(p);
38}
39
40void arch_wb_cache_pmem(void *addr, size_t size)
41{
42 clean_cache_range(addr, size);
43}
44EXPORT_SYMBOL_GPL(arch_wb_cache_pmem);
45
46long __copy_user_flushcache(void *dst, const void __user *src, unsigned size)
47{
48 unsigned long flushed, dest = (unsigned long) dst;
49 long rc;
50
51 stac();
52 rc = __copy_user_nocache(dst, src, size);
53 clac();
54
55 /*
56 * __copy_user_nocache() uses non-temporal stores for the bulk
57 * of the transfer, but we need to manually flush if the
58 * transfer is unaligned. A cached memory copy is used when
59 * destination or size is not naturally aligned. That is:
60 * - Require 8-byte alignment when size is 8 bytes or larger.
61 * - Require 4-byte alignment when size is 4 bytes.
62 */
63 if (size < 8) {
64 if (!IS_ALIGNED(dest, 4) || size != 4)
65 clean_cache_range(dst, size);
66 } else {
67 if (!IS_ALIGNED(dest, 8)) {
68 dest = ALIGN(dest, boot_cpu_data.x86_clflush_size);
69 clean_cache_range(dst, 1);
70 }
71
72 flushed = dest - (unsigned long) dst;
73 if (size > flushed && !IS_ALIGNED(size - flushed, 8))
74 clean_cache_range(dst + size - 1, 1);
75 }
76
77 return rc;
78}
79
80void __memcpy_flushcache(void *_dst, const void *_src, size_t size)
81{
82 unsigned long dest = (unsigned long) _dst;
83 unsigned long source = (unsigned long) _src;
84
85 /* cache copy and flush to align dest */
86 if (!IS_ALIGNED(dest, 8)) {
87 size_t len = min_t(size_t, size, ALIGN(dest, 8) - dest);
88
89 memcpy((void *) dest, (void *) source, len);
90 clean_cache_range((void *) dest, len);
91 dest += len;
92 source += len;
93 size -= len;
94 if (!size)
95 return;
96 }
97
98 /* 4x8 movnti loop */
99 while (size >= 32) {
100 asm("movq (%0), %%r8\n"
101 "movq 8(%0), %%r9\n"
102 "movq 16(%0), %%r10\n"
103 "movq 24(%0), %%r11\n"
104 "movnti %%r8, (%1)\n"
105 "movnti %%r9, 8(%1)\n"
106 "movnti %%r10, 16(%1)\n"
107 "movnti %%r11, 24(%1)\n"
108 :: "r" (source), "r" (dest)
109 : "memory", "r8", "r9", "r10", "r11");
110 dest += 32;
111 source += 32;
112 size -= 32;
113 }
114
115 /* 1x8 movnti loop */
116 while (size >= 8) {
117 asm("movq (%0), %%r8\n"
118 "movnti %%r8, (%1)\n"
119 :: "r" (source), "r" (dest)
120 : "memory", "r8");
121 dest += 8;
122 source += 8;
123 size -= 8;
124 }
125
126 /* 1x4 movnti loop */
127 while (size >= 4) {
128 asm("movl (%0), %%r8d\n"
129 "movnti %%r8d, (%1)\n"
130 :: "r" (source), "r" (dest)
131 : "memory", "r8");
132 dest += 4;
133 source += 4;
134 size -= 4;
135 }
136
137 /* cache copy for remaining bytes */
138 if (size) {
139 memcpy((void *) dest, (void *) source, size);
140 clean_cache_range((void *) dest, size);
141 }
142}
143EXPORT_SYMBOL_GPL(__memcpy_flushcache);
144#endif