From: Alexander Kuleshov <[email protected]> We are using %rax as temporary register to check the kernel address alignment. We don't really have to since the TEST instruction does not clobber the destination operand.
Suggested-by: Brian Gerst <[email protected]> Signed-off-by: Alexander Kuleshov <[email protected]> Cc: Alexander Popov <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Thomas Gleixner <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Borislav Petkov <[email protected]> --- arch/x86/kernel/head_64.S | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index ffdc0e860390..7c21029cb733 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -76,9 +76,7 @@ startup_64: subq $_text - __START_KERNEL_map, %rbp /* Is the address not 2M aligned? */ - movq %rbp, %rax - andl $~PMD_PAGE_MASK, %eax - testl %eax, %eax + testl $~PMD_PAGE_MASK, %ebp jnz bad_address /* -- 2.3.5
