2 * User address space access functions.
4 * Copyright 1997 Andi Kleen <ak@muc.de>
5 * Copyright 1997 Linus Torvalds
6 * Copyright 2002 Andi Kleen <ak@suse.de>
8 #include <linux/export.h>
9 #include <linux/uaccess.h>
10 #include <linux/highmem.h>
16 unsigned long __clear_user(void __user *addr, unsigned long size)
20 /* no memory constraint because it doesn't change any memory gcc knows
24 " testq %[size8],%[size8]\n"
26 "0: movq $0,(%[dst])\n"
28 " decl %%ecx ; jnz 0b\n"
29 "4: movq %[size1],%%rcx\n"
30 " testl %%ecx,%%ecx\n"
32 "1: movb $0,(%[dst])\n"
34 " decl %%ecx ; jnz 1b\n"
36 ".section .fixup,\"ax\"\n"
37 "3: lea 0(%[size1],%[size8],8),%[size8]\n"
40 _ASM_EXTABLE_UA(0b, 3b)
41 _ASM_EXTABLE_UA(1b, 2b)
42 : [size8] "=&c"(size), [dst] "=&D" (__d0)
43 : [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr));
47 EXPORT_SYMBOL(__clear_user);
49 unsigned long clear_user(void __user *to, unsigned long n)
52 return __clear_user(to, n);
55 EXPORT_SYMBOL(clear_user);
58 * Try to copy last bytes and clear the rest if needed.
59 * Since protection fault in copy_from/to_user is not a normal situation,
60 * it is not necessary to optimize tail handling.
62 __visible unsigned long
63 copy_user_handle_tail(char *to, char *from, unsigned len)
65 for (; len; --len, to++) {
68 if (__get_user_nocheck(c, from++, sizeof(char)))
70 if (__put_user_nocheck(c, to, sizeof(char)))
78 * Similar to copy_user_handle_tail, probe for the write fault point,
79 * but reuse __memcpy_mcsafe in case a new read error is encountered.
80 * clac() is handled in _copy_to_iter_mcsafe().
82 __visible unsigned long
83 mcsafe_handle_tail(char *to, char *from, unsigned len)
85 for (; len; --len, to++, from++) {
87 * Call the assembly routine back directly since
88 * memcpy_mcsafe() may silently fallback to memcpy.
90 unsigned long rem = __memcpy_mcsafe(to, from, 1);
98 #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
100 * clean_cache_range - write back a cache range with CLWB
101 * @vaddr: virtual start address
102 * @size: number of bytes to write back
104 * Write back a cache range using the CLWB (cache line write back)
105 * instruction. Note that @size is internally rounded up to be cache
108 static void clean_cache_range(void *addr, size_t size)
110 u16 x86_clflush_size = boot_cpu_data.x86_clflush_size;
111 unsigned long clflush_mask = x86_clflush_size - 1;
112 void *vend = addr + size;
115 for (p = (void *)((unsigned long)addr & ~clflush_mask);
116 p < vend; p += x86_clflush_size)
120 void arch_wb_cache_pmem(void *addr, size_t size)
122 clean_cache_range(addr, size);
124 EXPORT_SYMBOL_GPL(arch_wb_cache_pmem);
126 long __copy_user_flushcache(void *dst, const void __user *src, unsigned size)
128 unsigned long flushed, dest = (unsigned long) dst;
129 long rc = __copy_user_nocache(dst, src, size, 0);
132 * __copy_user_nocache() uses non-temporal stores for the bulk
133 * of the transfer, but we need to manually flush if the
134 * transfer is unaligned. A cached memory copy is used when
135 * destination or size is not naturally aligned. That is:
136 * - Require 8-byte alignment when size is 8 bytes or larger.
137 * - Require 4-byte alignment when size is 4 bytes.
140 if (!IS_ALIGNED(dest, 4) || size != 4)
141 clean_cache_range(dst, 1);
143 if (!IS_ALIGNED(dest, 8)) {
144 dest = ALIGN(dest, boot_cpu_data.x86_clflush_size);
145 clean_cache_range(dst, 1);
148 flushed = dest - (unsigned long) dst;
149 if (size > flushed && !IS_ALIGNED(size - flushed, 8))
150 clean_cache_range(dst + size - 1, 1);
156 void __memcpy_flushcache(void *_dst, const void *_src, size_t size)
158 unsigned long dest = (unsigned long) _dst;
159 unsigned long source = (unsigned long) _src;
161 /* cache copy and flush to align dest */
162 if (!IS_ALIGNED(dest, 8)) {
163 unsigned len = min_t(unsigned, size, ALIGN(dest, 8) - dest);
165 memcpy((void *) dest, (void *) source, len);
166 clean_cache_range((void *) dest, len);
174 /* 4x8 movnti loop */
176 asm("movq (%0), %%r8\n"
178 "movq 16(%0), %%r10\n"
179 "movq 24(%0), %%r11\n"
180 "movnti %%r8, (%1)\n"
181 "movnti %%r9, 8(%1)\n"
182 "movnti %%r10, 16(%1)\n"
183 "movnti %%r11, 24(%1)\n"
184 :: "r" (source), "r" (dest)
185 : "memory", "r8", "r9", "r10", "r11");
191 /* 1x8 movnti loop */
193 asm("movq (%0), %%r8\n"
194 "movnti %%r8, (%1)\n"
195 :: "r" (source), "r" (dest)
202 /* 1x4 movnti loop */
204 asm("movl (%0), %%r8d\n"
205 "movnti %%r8d, (%1)\n"
206 :: "r" (source), "r" (dest)
213 /* cache copy for remaining bytes */
215 memcpy((void *) dest, (void *) source, size);
216 clean_cache_range((void *) dest, size);
219 EXPORT_SYMBOL_GPL(__memcpy_flushcache);
221 void memcpy_page_flushcache(char *to, struct page *page, size_t offset,
224 char *from = kmap_atomic(page);
226 memcpy_flushcache(to, from + offset, len);