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