2 files changed, 6 insertions, 4 deletions

diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index 623f28837476..8f8e8eea9085 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -1016,7 +1016,7 @@ ENTRY(xen_sysenter_target)
 
 ENTRY(xen_hypervisor_callback)
         CFI_STARTPROC
-        pushl_cfi $0
+        pushl_cfi $-1 /* orig_ax = -1 => not a system call */
         SAVE_ALL
         TRACE_IRQS_OFF
 
@@ -1058,14 +1058,16 @@ ENTRY(xen_failsafe_callback)
 2:      mov 8(%esp),%es
 3:      mov 12(%esp),%fs
 4:      mov 16(%esp),%gs
+        /* EAX == 0 => Category 1 (Bad segment)
+           EAX != 0 => Category 2 (Bad IRET) */
         testl %eax,%eax
         popl_cfi %eax
         lea 16(%esp),%esp
         CFI_ADJUST_CFA_OFFSET -16
         jz 5f
         addl $16,%esp
-        jmp iret_exc            # EAX != 0 => Category 2 (Bad IRET)
-5:      pushl_cfi $0            # EAX == 0 => Category 1 (Bad segment)
+        jmp iret_exc
+5:      pushl_cfi $-1 /* orig_ax = -1 => not a system call */
         SAVE_ALL
         jmp ret_from_exception
         CFI_ENDPROC
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 69babd8c834f..dcdd0ea33a32 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -1363,7 +1363,7 @@ ENTRY(xen_failsafe_callback)
         CFI_RESTORE r11
         addq $0x30,%rsp
         CFI_ADJUST_CFA_OFFSET -0x30
-        pushq_cfi $0
+        pushq_cfi $-1 /* orig_ax = -1 => not a system call */
         SAVE_ALL
         jmp error_exit
         CFI_ENDPROC