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  */
clean_cache_range(void * addr,size_t size)28 static 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 
arch_wb_cache_pmem(void * addr,size_t size)40 void arch_wb_cache_pmem(void *addr, size_t size)
41 {
42 	clean_cache_range(addr, size);
43 }
44 EXPORT_SYMBOL_GPL(arch_wb_cache_pmem);
45 
__copy_user_flushcache(void * dst,const void __user * src,unsigned size)46 long __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 
__memcpy_flushcache(void * _dst,const void * _src,size_t size)80 void __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 }
143 EXPORT_SYMBOL_GPL(__memcpy_flushcache);
144 #endif
145