x86_32: remove unnecessary use of %ebx as the boot cpu flag
Currently in head_32.S there are two ways we test to see if we
are the boot cpu. By looking at %ebx and by looking at the
static variable ready. When changing things around I have
found that it gets tricky to preserve %ebx. So this
patch just switches head.S over to the more reliable
test of always using ready.
Hopefully later we can kill these tests entirely.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Ian Campbell <ijc@hellion.org.uk>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Mika Penttilä <mika.penttila@kolumbus.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index f409fe2..7b9b256 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -199,7 +199,6 @@
addl $0x67, %eax /* 0x67 == _PAGE_TABLE */
movl %eax, 4092(%edx)
- xorl %ebx,%ebx /* This is the boot CPU (BSP) */
jmp 3f
/*
* Non-boot CPU entry point; entered from trampoline.S
@@ -268,10 +267,6 @@
wrmsr
6:
- /* This is a secondary processor (AP) */
- xorl %ebx,%ebx
- incl %ebx
-
#endif /* CONFIG_SMP */
3:
@@ -297,7 +292,7 @@
popfl
#ifdef CONFIG_SMP
- andl %ebx,%ebx
+ cmpb $0, ready
jz 1f /* Initial CPU cleans BSS */
jmp checkCPUtype
1: