1 files changed, 224 insertions, 0 deletions

diff --git a/arch/x86/lib/memmove_64.S b/arch/x86/lib/memmove_64.S
new file mode 100644
index 000000000000..d0ec9c2936d7
--- /dev/null
+++ b/arch/x86/lib/memmove_64.S
@@ -0,0 +1,224 @@
+/*
+ * 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>
+ */
+#define _STRING_C
+#include <linux/linkage.h>
+#include <asm/dwarf2.h>
+#include <asm/cpufeature.h>
+
+#undef memmove
+
+/*
+ * Implement memmove(). This can handle overlap between src and dst.
+ *
+ * Input:
+ * rdi: dest
+ * rsi: src
+ * rdx: count
+ *
+ * Output:
+ * rax: dest
+ */
+ENTRY(memmove)
+        CFI_STARTPROC
+
+        /* Handle more 32bytes 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:
+        /*
+         * 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 32byts 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 32byts 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
+        CFI_ENDPROC
+
+        .section .altinstr_replacement,"ax"
+.Lmemmove_begin_forward_efs:
+        /* Forward moving data. */
+        movq %rdx, %rcx
+        rep movsb
+        retq
+.Lmemmove_end_forward_efs:
+        .previous
+
+        .section .altinstructions,"a"
+        .align 8
+        .quad .Lmemmove_begin_forward
+        .quad .Lmemmove_begin_forward_efs
+        .word X86_FEATURE_ERMS
+        .byte .Lmemmove_end_forward-.Lmemmove_begin_forward
+        .byte .Lmemmove_end_forward_efs-.Lmemmove_begin_forward_efs
+        .previous
+ENDPROC(memmove)