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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 | /* Copyright 2002 Andi Kleen */ #include <linux/linkage.h> #include <asm/errno.h> #include <asm/cpufeatures.h> #include <asm/alternative-asm.h> #include <asm/export.h> /* * We build a jump to memcpy_orig by default which gets NOPped out on * the majority of x86 CPUs which set REP_GOOD. In addition, CPUs which * have the enhanced REP MOVSB/STOSB feature (ERMS), change those NOPs * to a jmp to memcpy_erms which does the REP; MOVSB mem copy. */ .weak memcpy /* * memcpy - Copy a memory block. * * Input: * rdi destination * rsi source * rdx count * * Output: * rax original destination */ ENTRY(__memcpy) ENTRY(memcpy) ALTERNATIVE_2 "jmp memcpy_orig", "", X86_FEATURE_REP_GOOD, \ "jmp memcpy_erms", X86_FEATURE_ERMS movq %rdi, %rax movq %rdx, %rcx shrq $3, %rcx andl $7, %edx rep movsq movl %edx, %ecx rep movsb ret ENDPROC(memcpy) ENDPROC(__memcpy) EXPORT_SYMBOL(memcpy) EXPORT_SYMBOL(__memcpy) /* * memcpy_erms() - enhanced fast string memcpy. This is faster and * simpler than memcpy. Use memcpy_erms when possible. */ ENTRY(memcpy_erms) movq %rdi, %rax movq %rdx, %rcx rep movsb ret ENDPROC(memcpy_erms) ENTRY(memcpy_orig) movq %rdi, %rax cmpq $0x20, %rdx jb .Lhandle_tail /* * We check whether memory false dependence could occur, * then jump to corresponding copy mode. */ cmp %dil, %sil jl .Lcopy_backward subq $0x20, %rdx .Lcopy_forward_loop: subq $0x20, %rdx /* * Move in blocks of 4x8 bytes: */ movq 0*8(%rsi), %r8 movq 1*8(%rsi), %r9 movq 2*8(%rsi), %r10 movq 3*8(%rsi), %r11 leaq 4*8(%rsi), %rsi movq %r8, 0*8(%rdi) movq %r9, 1*8(%rdi) movq %r10, 2*8(%rdi) movq %r11, 3*8(%rdi) leaq 4*8(%rdi), %rdi jae .Lcopy_forward_loop addl $0x20, %edx jmp .Lhandle_tail .Lcopy_backward: /* * Calculate copy position to tail. */ addq %rdx, %rsi addq %rdx, %rdi subq $0x20, %rdx /* * At most 3 ALU operations in one cycle, * so append NOPS in the same 16 bytes trunk. */ .p2align 4 .Lcopy_backward_loop: subq $0x20, %rdx movq -1*8(%rsi), %r8 movq -2*8(%rsi), %r9 movq -3*8(%rsi), %r10 movq -4*8(%rsi), %r11 leaq -4*8(%rsi), %rsi movq %r8, -1*8(%rdi) movq %r9, -2*8(%rdi) movq %r10, -3*8(%rdi) movq %r11, -4*8(%rdi) leaq -4*8(%rdi), %rdi jae .Lcopy_backward_loop /* * Calculate copy position to head. */ addl $0x20, %edx subq %rdx, %rsi subq %rdx, %rdi .Lhandle_tail: cmpl $16, %edx jb .Lless_16bytes /* * Move data from 16 bytes to 31 bytes. */ movq 0*8(%rsi), %r8 movq 1*8(%rsi), %r9 movq -2*8(%rsi, %rdx), %r10 movq -1*8(%rsi, %rdx), %r11 movq %r8, 0*8(%rdi) movq %r9, 1*8(%rdi) movq %r10, -2*8(%rdi, %rdx) movq %r11, -1*8(%rdi, %rdx) retq .p2align 4 .Lless_16bytes: cmpl $8, %edx jb .Lless_8bytes /* * Move data from 8 bytes to 15 bytes. */ movq 0*8(%rsi), %r8 movq -1*8(%rsi, %rdx), %r9 movq %r8, 0*8(%rdi) movq %r9, -1*8(%rdi, %rdx) retq .p2align 4 .Lless_8bytes: cmpl $4, %edx jb .Lless_3bytes /* * Move data from 4 bytes to 7 bytes. */ movl (%rsi), %ecx movl -4(%rsi, %rdx), %r8d movl %ecx, (%rdi) movl %r8d, -4(%rdi, %rdx) retq .p2align 4 .Lless_3bytes: subl $1, %edx jb .Lend /* * Move data from 1 bytes to 3 bytes. */ movzbl (%rsi), %ecx jz .Lstore_1byte movzbq 1(%rsi), %r8 movzbq (%rsi, %rdx), %r9 movb %r8b, 1(%rdi) movb %r9b, (%rdi, %rdx) .Lstore_1byte: movb %cl, (%rdi) .Lend: retq ENDPROC(memcpy_orig) #ifndef CONFIG_UML /* * memcpy_mcsafe_unrolled - memory copy with machine check exception handling * Note that we only catch machine checks when reading the source addresses. * Writes to target are posted and don't generate machine checks. */ ENTRY(memcpy_mcsafe_unrolled) cmpl $8, %edx /* Less than 8 bytes? Go to byte copy loop */ jb .L_no_whole_words /* Check for bad alignment of source */ testl $7, %esi /* Already aligned */ jz .L_8byte_aligned /* Copy one byte at a time until source is 8-byte aligned */ movl %esi, %ecx andl $7, %ecx subl $8, %ecx negl %ecx subl %ecx, %edx .L_copy_leading_bytes: movb (%rsi), %al movb %al, (%rdi) incq %rsi incq %rdi decl %ecx jnz .L_copy_leading_bytes .L_8byte_aligned: /* Figure out how many whole cache lines (64-bytes) to copy */ movl %edx, %ecx andl $63, %edx shrl $6, %ecx jz .L_no_whole_cache_lines /* Loop copying whole cache lines */ .L_cache_w0: movq (%rsi), %r8 .L_cache_w1: movq 1*8(%rsi), %r9 .L_cache_w2: movq 2*8(%rsi), %r10 .L_cache_w3: movq 3*8(%rsi), %r11 movq %r8, (%rdi) movq %r9, 1*8(%rdi) movq %r10, 2*8(%rdi) movq %r11, 3*8(%rdi) .L_cache_w4: movq 4*8(%rsi), %r8 .L_cache_w5: movq 5*8(%rsi), %r9 .L_cache_w6: movq 6*8(%rsi), %r10 .L_cache_w7: movq 7*8(%rsi), %r11 movq %r8, 4*8(%rdi) movq %r9, 5*8(%rdi) movq %r10, 6*8(%rdi) movq %r11, 7*8(%rdi) leaq 64(%rsi), %rsi leaq 64(%rdi), %rdi decl %ecx jnz .L_cache_w0 /* Are there any trailing 8-byte words? */ .L_no_whole_cache_lines: movl %edx, %ecx andl $7, %edx shrl $3, %ecx jz .L_no_whole_words /* Copy trailing words */ .L_copy_trailing_words: movq (%rsi), %r8 mov %r8, (%rdi) leaq 8(%rsi), %rsi leaq 8(%rdi), %rdi decl %ecx jnz .L_copy_trailing_words /* Any trailing bytes? */ .L_no_whole_words: andl %edx, %edx jz .L_done_memcpy_trap /* Copy trailing bytes */ movl %edx, %ecx .L_copy_trailing_bytes: movb (%rsi), %al movb %al, (%rdi) incq %rsi incq %rdi decl %ecx jnz .L_copy_trailing_bytes /* Copy successful. Return zero */ .L_done_memcpy_trap: xorq %rax, %rax ret ENDPROC(memcpy_mcsafe_unrolled) EXPORT_SYMBOL_GPL(memcpy_mcsafe_unrolled) .section .fixup, "ax" /* Return -EFAULT for any failure */ .L_memcpy_mcsafe_fail: mov $-EFAULT, %rax ret .previous _ASM_EXTABLE_FAULT(.L_copy_leading_bytes, .L_memcpy_mcsafe_fail) _ASM_EXTABLE_FAULT(.L_cache_w0, .L_memcpy_mcsafe_fail) _ASM_EXTABLE_FAULT(.L_cache_w1, .L_memcpy_mcsafe_fail) _ASM_EXTABLE_FAULT(.L_cache_w2, .L_memcpy_mcsafe_fail) _ASM_EXTABLE_FAULT(.L_cache_w3, .L_memcpy_mcsafe_fail) _ASM_EXTABLE_FAULT(.L_cache_w4, .L_memcpy_mcsafe_fail) _ASM_EXTABLE_FAULT(.L_cache_w5, .L_memcpy_mcsafe_fail) _ASM_EXTABLE_FAULT(.L_cache_w6, .L_memcpy_mcsafe_fail) _ASM_EXTABLE_FAULT(.L_cache_w7, .L_memcpy_mcsafe_fail) _ASM_EXTABLE_FAULT(.L_copy_trailing_words, .L_memcpy_mcsafe_fail) _ASM_EXTABLE_FAULT(.L_copy_trailing_bytes, .L_memcpy_mcsafe_fail) #endif |