xen: fold xen_sysexit into xen_iret

xen_sysexit and xen_iret were doing essentially the same thing.  Rather
than having a separate implementation for xen_sysexit, we can just strip
the stack back to an iret frame and jump into xen_iret.  This removes
a lot of code and complexity - specifically, another critical region.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 1 insertions, 8 deletions

diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index 209c334bb920..2a609dc3271c 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -1044,15 +1044,8 @@ ENTRY(xen_hypervisor_callback)
 
         jmp  xen_iret_crit_fixup
 
-1:      cmpl $xen_sysexit_start_crit,%eax
-        jb   2f
-        cmpl $xen_sysexit_end_crit,%eax
-        jae  2f
-
-        jmp xen_sysexit_crit_fixup
-
 ENTRY(xen_do_upcall)
-2:      mov %esp, %eax
+1:      mov %esp, %eax
         call xen_evtchn_do_upcall
         jmp  ret_from_intr
         CFI_ENDPROC