x86, boot: use appropriate rep string for move and clear

[pandora-kernel.git] / arch / x86 / boot / compressed / head_64.S

diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index a0b1842..723c72d 100644 (file)
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -260,15 +260,15 @@ ENTRY(startup_64)
  * Copy the compressed kernel to the end of our buffer
  * where decompression in place becomes safe.
  */
-       leaq    _bss(%rip), %r8
-       leaq    _bss(%rbx), %r9
+       pushq   %rsi
+       leaq    (_bss-8)(%rip), %rsi
+       leaq    (_bss-8)(%rbx), %rdi
        movq    $_bss /* - $startup_32 */, %rcx
-1:     subq    $8, %r8
-       subq    $8, %r9
-       movq    0(%r8), %rax
-       movq    %rax, 0(%r9)
-       subq    $8, %rcx
-       jnz     1b
+       shrq    $3, %rcx
+       std
+       rep     movsq
+       cld
+       popq    %rsi
 
 /*
  * Jump to the relocated address.
@@ -282,12 +282,12 @@ relocated:
 /*
  * Clear BSS (stack is currently empty)
  */
-       xorq    %rax, %rax
-       leaq    _bss(%rbx), %rdi
-       leaq    _ebss(%rbx), %rcx
+       xorl    %eax, %eax
+       leaq    _bss(%rip), %rdi
+       leaq    _ebss(%rip), %rcx
        subq    %rdi, %rcx
-       cld
-       rep     stosb
+       shrq    $3, %rcx
+       rep     stosq
 
 /*
  * Do the decompression, and jump to the new kernel..