Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S
index 8019edd..be104ee 100644
--- a/arch/x86/xen/xen-asm.S
+++ b/arch/x86/xen/xen-asm.S
@@ -10,6 +10,7 @@
 #include <asm/percpu.h>
 #include <asm/processor-flags.h>
 #include <asm/frame.h>
+#include <asm/asm.h>
 
 #include <linux/linkage.h>
 
@@ -135,3 +136,18 @@
 	FRAME_END
 	ret
 ENDPROC(check_events)
+
+ENTRY(xen_read_cr2)
+	FRAME_BEGIN
+	_ASM_MOV PER_CPU_VAR(xen_vcpu), %_ASM_AX
+	_ASM_MOV XEN_vcpu_info_arch_cr2(%_ASM_AX), %_ASM_AX
+	FRAME_END
+	ret
+	ENDPROC(xen_read_cr2);
+
+ENTRY(xen_read_cr2_direct)
+	FRAME_BEGIN
+	_ASM_MOV PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_arch_cr2, %_ASM_AX
+	FRAME_END
+	ret
+	ENDPROC(xen_read_cr2_direct);