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(VERIFY_WRITE, to, n)) 52 return __clear_user(to, n); 53 return n; 54 } 55 EXPORT_SYMBOL(clear_user); 56 57 /* 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. 61 */ 62 __visible unsigned long 63 copy_user_handle_tail(char *to, char *from, unsigned len) 64 { 65 for (; len; --len, to++) { 66 char c; 67 68 if (__get_user_nocheck(c, from++, sizeof(char))) 69 break; 70 if (__put_user_nocheck(c, to, sizeof(char))) 71 break; 72 } 73 clac(); 74 return len; 75 } 76 77 /* 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(). 81 */ 82 __visible unsigned long 83 mcsafe_handle_tail(char *to, char *from, unsigned len) 84 { 85 for (; len; --len, to++, from++) { 86 /* 87 * Call the assembly routine back directly since 88 * memcpy_mcsafe() may silently fallback to memcpy. 89 */ 90 unsigned long rem = __memcpy_mcsafe(to, from, 1); 91 92 if (rem) 93 break; 94 } 95 return len; 96 } 97 98 #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE 99 /** 100 * clean_cache_range - write back a cache range with CLWB 101 * @vaddr: virtual start address 102 * @size: number of bytes to write back 103 * 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 106 * line size aligned. 107 */ 108 static void clean_cache_range(void *addr, size_t size) 109 { 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; 113 void *p; 114 115 for (p = (void *)((unsigned long)addr & ~clflush_mask); 116 p < vend; p += x86_clflush_size) 117 clwb(p); 118 } 119 120 void arch_wb_cache_pmem(void *addr, size_t size) 121 { 122 clean_cache_range(addr, size); 123 } 124 EXPORT_SYMBOL_GPL(arch_wb_cache_pmem); 125 126 long __copy_user_flushcache(void *dst, const void __user *src, unsigned size) 127 { 128 unsigned long flushed, dest = (unsigned long) dst; 129 long rc = __copy_user_nocache(dst, src, size, 0); 130 131 /* 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. 138 */ 139 if (size < 8) { 140 if (!IS_ALIGNED(dest, 4) || size != 4) 141 clean_cache_range(dst, 1); 142 } else { 143 if (!IS_ALIGNED(dest, 8)) { 144 dest = ALIGN(dest, boot_cpu_data.x86_clflush_size); 145 clean_cache_range(dst, 1); 146 } 147 148 flushed = dest - (unsigned long) dst; 149 if (size > flushed && !IS_ALIGNED(size - flushed, 8)) 150 clean_cache_range(dst + size - 1, 1); 151 } 152 153 return rc; 154 } 155 156 void memcpy_flushcache(void *_dst, const void *_src, size_t size) 157 { 158 unsigned long dest = (unsigned long) _dst; 159 unsigned long source = (unsigned long) _src; 160 161 /* cache copy and flush to align dest */ 162 if (!IS_ALIGNED(dest, 8)) { 163 unsigned len = min_t(unsigned, size, ALIGN(dest, 8) - dest); 164 165 memcpy((void *) dest, (void *) source, len); 166 clean_cache_range((void *) dest, len); 167 dest += len; 168 source += len; 169 size -= len; 170 if (!size) 171 return; 172 } 173 174 /* 4x8 movnti loop */ 175 while (size >= 32) { 176 asm("movq (%0), %%r8\n" 177 "movq 8(%0), %%r9\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"); 186 dest += 32; 187 source += 32; 188 size -= 32; 189 } 190 191 /* 1x8 movnti loop */ 192 while (size >= 8) { 193 asm("movq (%0), %%r8\n" 194 "movnti %%r8, (%1)\n" 195 :: "r" (source), "r" (dest) 196 : "memory", "r8"); 197 dest += 8; 198 source += 8; 199 size -= 8; 200 } 201 202 /* 1x4 movnti loop */ 203 while (size >= 4) { 204 asm("movl (%0), %%r8d\n" 205 "movnti %%r8d, (%1)\n" 206 :: "r" (source), "r" (dest) 207 : "memory", "r8"); 208 dest += 4; 209 source += 4; 210 size -= 4; 211 } 212 213 /* cache copy for remaining bytes */ 214 if (size) { 215 memcpy((void *) dest, (void *) source, size); 216 clean_cache_range((void *) dest, size); 217 } 218 } 219 EXPORT_SYMBOL_GPL(memcpy_flushcache); 220 221 void memcpy_page_flushcache(char *to, struct page *page, size_t offset, 222 size_t len) 223 { 224 char *from = kmap_atomic(page); 225 226 memcpy_flushcache(to, from + offset, len); 227 kunmap_atomic(from); 228 } 229 #endif 230