xen: make sure iret faults are trapped

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>

2 files changed, 6 insertions, 2 deletions

diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index f0f8934fc30..568c6ccd7ae 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -409,7 +409,7 @@ restore_nocheck_notrace:
 irq_return:
         INTERRUPT_RETURN
 .section .fixup,"ax"
-iret_exc:
+ENTRY(iret_exc)
         pushl $0                        # no error code
         pushl $do_iret_error
         jmp error_code
diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S
index fe161ed4b01..99223cc323b 100644
--- a/arch/x86/xen/xen-asm.S
+++ b/arch/x86/xen/xen-asm.S
@@ -184,8 +184,12 @@ iret_restore_end:
            region is OK. */
         je xen_hypervisor_callback
 
-        iret
+1:      iret
 xen_iret_end_crit:
+.section __ex_table,"a"
+        .align 4
+        .long 1b,iret_exc
+.previous
 
 hyper_iret:
         /* put this out of line since its very rarely used */