x86: remove open-coded save/load segment operations
This removes a pile of buggy open-coded implementations of savesegment
and loadsegment.
(They are buggy because they don't have memory barriers to prevent
them from being reordered with respect to memory accesses.)
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: xen-devel <xen-devel@lists.xensource.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/cpu/common_64.c b/arch/x86/kernel/cpu/common_64.c
index 39eaefb..7518502 100644
--- a/arch/x86/kernel/cpu/common_64.c
+++ b/arch/x86/kernel/cpu/common_64.c
@@ -480,7 +480,8 @@
struct x8664_pda *pda = cpu_pda(cpu);
/* Setup up data that may be needed in __get_free_pages early */
- asm volatile("movl %0,%%fs ; movl %0,%%gs" :: "r" (0));
+ loadsegment(fs, 0);
+ loadsegment(gs, 0);
/* Memory clobbers used to order PDA accessed */
mb();
wrmsrl(MSR_GS_BASE, pda);
