kernel_optimize_test/arch/x86/lib/memmove_64.S
Borislav Petkov cd4d09ec6f x86/cpufeature: Carve out X86_FEATURE_*
Move them to a separate header and have the following
dependency:

  x86/cpufeatures.h <- x86/processor.h <- x86/cpufeature.h

This makes it easier to use the header in asm code and not
include the whole cpufeature.h and add guards for asm.

Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1453842730-28463-5-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-01-30 11:22:17 +01:00

210 lines
3.4 KiB
ArmAsm

/*
* Normally compiler builtins are used, but sometimes the compiler calls out
* of line code. Based on asm-i386/string.h.
*
* This assembly file is re-written from memmove_64.c file.
* - Copyright 2011 Fenghua Yu <fenghua.yu@intel.com>
*/
#include <linux/linkage.h>
#include <asm/cpufeatures.h>
#include <asm/alternative-asm.h>
#undef memmove
/*
* Implement memmove(). This can handle overlap between src and dst.
*
* Input:
* rdi: dest
* rsi: src
* rdx: count
*
* Output:
* rax: dest
*/
.weak memmove
ENTRY(memmove)
ENTRY(__memmove)
/* Handle more 32 bytes in loop */
mov %rdi, %rax
cmp $0x20, %rdx
jb 1f
/* Decide forward/backward copy mode */
cmp %rdi, %rsi
jge .Lmemmove_begin_forward
mov %rsi, %r8
add %rdx, %r8
cmp %rdi, %r8
jg 2f
.Lmemmove_begin_forward:
ALTERNATIVE "", "movq %rdx, %rcx; rep movsb; retq", X86_FEATURE_ERMS
/*
* movsq instruction have many startup latency
* so we handle small size by general register.
*/
cmp $680, %rdx
jb 3f
/*
* movsq instruction is only good for aligned case.
*/
cmpb %dil, %sil
je 4f
3:
sub $0x20, %rdx
/*
* We gobble 32 bytes forward in each loop.
*/
5:
sub $0x20, %rdx
movq 0*8(%rsi), %r11
movq 1*8(%rsi), %r10
movq 2*8(%rsi), %r9
movq 3*8(%rsi), %r8
leaq 4*8(%rsi), %rsi
movq %r11, 0*8(%rdi)
movq %r10, 1*8(%rdi)
movq %r9, 2*8(%rdi)
movq %r8, 3*8(%rdi)
leaq 4*8(%rdi), %rdi
jae 5b
addq $0x20, %rdx
jmp 1f
/*
* Handle data forward by movsq.
*/
.p2align 4
4:
movq %rdx, %rcx
movq -8(%rsi, %rdx), %r11
lea -8(%rdi, %rdx), %r10
shrq $3, %rcx
rep movsq
movq %r11, (%r10)
jmp 13f
.Lmemmove_end_forward:
/*
* Handle data backward by movsq.
*/
.p2align 4
7:
movq %rdx, %rcx
movq (%rsi), %r11
movq %rdi, %r10
leaq -8(%rsi, %rdx), %rsi
leaq -8(%rdi, %rdx), %rdi
shrq $3, %rcx
std
rep movsq
cld
movq %r11, (%r10)
jmp 13f
/*
* Start to prepare for backward copy.
*/
.p2align 4
2:
cmp $680, %rdx
jb 6f
cmp %dil, %sil
je 7b
6:
/*
* Calculate copy position to tail.
*/
addq %rdx, %rsi
addq %rdx, %rdi
subq $0x20, %rdx
/*
* We gobble 32 bytes backward in each loop.
*/
8:
subq $0x20, %rdx
movq -1*8(%rsi), %r11
movq -2*8(%rsi), %r10
movq -3*8(%rsi), %r9
movq -4*8(%rsi), %r8
leaq -4*8(%rsi), %rsi
movq %r11, -1*8(%rdi)
movq %r10, -2*8(%rdi)
movq %r9, -3*8(%rdi)
movq %r8, -4*8(%rdi)
leaq -4*8(%rdi), %rdi
jae 8b
/*
* Calculate copy position to head.
*/
addq $0x20, %rdx
subq %rdx, %rsi
subq %rdx, %rdi
1:
cmpq $16, %rdx
jb 9f
/*
* Move data from 16 bytes to 31 bytes.
*/
movq 0*8(%rsi), %r11
movq 1*8(%rsi), %r10
movq -2*8(%rsi, %rdx), %r9
movq -1*8(%rsi, %rdx), %r8
movq %r11, 0*8(%rdi)
movq %r10, 1*8(%rdi)
movq %r9, -2*8(%rdi, %rdx)
movq %r8, -1*8(%rdi, %rdx)
jmp 13f
.p2align 4
9:
cmpq $8, %rdx
jb 10f
/*
* Move data from 8 bytes to 15 bytes.
*/
movq 0*8(%rsi), %r11
movq -1*8(%rsi, %rdx), %r10
movq %r11, 0*8(%rdi)
movq %r10, -1*8(%rdi, %rdx)
jmp 13f
10:
cmpq $4, %rdx
jb 11f
/*
* Move data from 4 bytes to 7 bytes.
*/
movl (%rsi), %r11d
movl -4(%rsi, %rdx), %r10d
movl %r11d, (%rdi)
movl %r10d, -4(%rdi, %rdx)
jmp 13f
11:
cmp $2, %rdx
jb 12f
/*
* Move data from 2 bytes to 3 bytes.
*/
movw (%rsi), %r11w
movw -2(%rsi, %rdx), %r10w
movw %r11w, (%rdi)
movw %r10w, -2(%rdi, %rdx)
jmp 13f
12:
cmp $1, %rdx
jb 13f
/*
* Move data for 1 byte.
*/
movb (%rsi), %r11b
movb %r11b, (%rdi)
13:
retq
ENDPROC(__memmove)
ENDPROC(memmove)