4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Alexander Kuleshov <[email protected]> commit a4733143085d6c782ac1e6c85778655b6bac1d4e upstream 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]> Signed-off-by: Borislav Petkov <[email protected]> Cc: Alexander Popov <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Srivatsa S. Bhat <[email protected]> Reviewed-by: Matt Helsley (VMware) <[email protected]> Reviewed-by: Alexey Makhalov <[email protected]> Reviewed-by: Bo Gan <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/x86/kernel/head_64.S | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) --- 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 /*
