x86: use stack_start in x86_64

call x86_64's init_rsp stack_start, just as i386 does.
Put a zeroed stack segment for consistency. With this,
we can eliminate one ugly ifdef in smpboot.c.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 2 deletions

diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 263b9d14753e..918a2711aff6 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -191,7 +191,7 @@ ENTRY(secondary_startup_64)
         movq    %rax, %cr0
 
         /* Setup a boot time stack */
-        movq init_rsp(%rip),%rsp
+        movq stack_start(%rip),%rsp
 
         /* zero EFLAGS after setting rsp */
         pushq $0
@@ -252,8 +252,9 @@ ENTRY(secondary_startup_64)
         .quad   x86_64_start_kernel
         __FINITDATA
 
-        ENTRY(init_rsp)
+        ENTRY(stack_start)
         .quad  init_thread_union+THREAD_SIZE-8
+        .word  0
 
 bad_address:
         jmp bad_address