diff options
Diffstat (limited to 'arch/x86/lib/memcpy_64.S')
| -rw-r--r-- | arch/x86/lib/memcpy_64.S | 178 |
1 files changed, 27 insertions, 151 deletions
diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S index 3b24dc05251c..12a23fa7c44c 100644 --- a/arch/x86/lib/memcpy_64.S +++ b/arch/x86/lib/memcpy_64.S @@ -1,20 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ /* Copyright 2002 Andi Kleen */ +#include <linux/export.h> #include <linux/linkage.h> +#include <linux/cfi_types.h> #include <asm/errno.h> #include <asm/cpufeatures.h> -#include <asm/mcsafe_test.h> -#include <asm/alternative-asm.h> -#include <asm/export.h> +#include <asm/alternative.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 +.section .noinstr.text, "ax" /* * memcpy - Copy a memory block. @@ -26,37 +20,31 @@ * * Output: * rax original destination + * + * The FSRM alternative should be done inline (avoiding the call and + * the disgusting return handling), but that would require some help + * from the compiler for better calling conventions. + * + * The 'rep movsb' itself is small enough to replace the call, but the + * two register moves blow up the code. And one of them is "needed" + * only for the return value that is the same as the source input, + * which the compiler could/should do much better anyway. */ -ENTRY(__memcpy) -ENTRY(memcpy) - ALTERNATIVE_2 "jmp memcpy_orig", "", X86_FEATURE_REP_GOOD, \ - "jmp memcpy_erms", X86_FEATURE_ERMS +SYM_TYPED_FUNC_START(__memcpy) + ALTERNATIVE "jmp memcpy_orig", "", X86_FEATURE_FSRM 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) + RET +SYM_FUNC_END(__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) +SYM_FUNC_ALIAS_MEMFUNC(memcpy, __memcpy) +SYM_PIC_ALIAS(memcpy) +EXPORT_SYMBOL(memcpy) -ENTRY(memcpy_orig) +SYM_FUNC_START_LOCAL(memcpy_orig) movq %rdi, %rax cmpq $0x20, %rdx @@ -137,7 +125,7 @@ ENTRY(memcpy_orig) movq %r9, 1*8(%rdi) movq %r10, -2*8(%rdi, %rdx) movq %r11, -1*8(%rdi, %rdx) - retq + RET .p2align 4 .Lless_16bytes: cmpl $8, %edx @@ -149,7 +137,7 @@ ENTRY(memcpy_orig) movq -1*8(%rsi, %rdx), %r9 movq %r8, 0*8(%rdi) movq %r9, -1*8(%rdi, %rdx) - retq + RET .p2align 4 .Lless_8bytes: cmpl $4, %edx @@ -162,7 +150,7 @@ ENTRY(memcpy_orig) movl -4(%rsi, %rdx), %r8d movl %ecx, (%rdi) movl %r8d, -4(%rdi, %rdx) - retq + RET .p2align 4 .Lless_3bytes: subl $1, %edx @@ -180,118 +168,6 @@ ENTRY(memcpy_orig) movb %cl, (%rdi) .Lend: - retq -ENDPROC(memcpy_orig) - -#ifndef CONFIG_UML - -MCSAFE_TEST_CTL - -/* - * __memcpy_mcsafe - 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) - 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_read_leading_bytes: - movb (%rsi), %al - MCSAFE_TEST_SRC %rsi 1 .E_leading_bytes - MCSAFE_TEST_DST %rdi 1 .E_leading_bytes -.L_write_leading_bytes: - movb %al, (%rdi) - incq %rsi - incq %rdi - decl %ecx - jnz .L_read_leading_bytes - -.L_8byte_aligned: - movl %edx, %ecx - andl $7, %edx - shrl $3, %ecx - jz .L_no_whole_words - -.L_read_words: - movq (%rsi), %r8 - MCSAFE_TEST_SRC %rsi 8 .E_read_words - MCSAFE_TEST_DST %rdi 8 .E_write_words -.L_write_words: - movq %r8, (%rdi) - addq $8, %rsi - addq $8, %rdi - decl %ecx - jnz .L_read_words - - /* Any trailing bytes? */ -.L_no_whole_words: - andl %edx, %edx - jz .L_done_memcpy_trap - - /* Copy trailing bytes */ - movl %edx, %ecx -.L_read_trailing_bytes: - movb (%rsi), %al - MCSAFE_TEST_SRC %rsi 1 .E_trailing_bytes - MCSAFE_TEST_DST %rdi 1 .E_trailing_bytes -.L_write_trailing_bytes: - movb %al, (%rdi) - incq %rsi - incq %rdi - decl %ecx - jnz .L_read_trailing_bytes - - /* Copy successful. Return zero */ -.L_done_memcpy_trap: - xorl %eax, %eax - ret -ENDPROC(__memcpy_mcsafe) -EXPORT_SYMBOL_GPL(__memcpy_mcsafe) - - .section .fixup, "ax" - /* - * Return number of bytes not copied for any failure. Note that - * there is no "tail" handling since the source buffer is 8-byte - * aligned and poison is cacheline aligned. - */ -.E_read_words: - shll $3, %ecx -.E_leading_bytes: - addl %edx, %ecx -.E_trailing_bytes: - mov %ecx, %eax - ret - - /* - * For write fault handling, given the destination is unaligned, - * we handle faults on multi-byte writes with a byte-by-byte - * copy up to the write-protected page. - */ -.E_write_words: - shll $3, %ecx - addl %edx, %ecx - movl %ecx, %edx - jmp mcsafe_handle_tail - - .previous + RET +SYM_FUNC_END(memcpy_orig) - _ASM_EXTABLE_FAULT(.L_read_leading_bytes, .E_leading_bytes) - _ASM_EXTABLE_FAULT(.L_read_words, .E_read_words) - _ASM_EXTABLE_FAULT(.L_read_trailing_bytes, .E_trailing_bytes) - _ASM_EXTABLE(.L_write_leading_bytes, .E_leading_bytes) - _ASM_EXTABLE(.L_write_words, .E_write_words) - _ASM_EXTABLE(.L_write_trailing_bytes, .E_trailing_bytes) -#endif |