xen: issue deprecation warning for 32-bit pv guest

Support for the kernel as Xen 32-bit PV guest will soon be removed.
Issue a warning when booted as such.
Signed-off-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>

arch/x86/xen/enlighten_pv.c

@@ -117,6 +117,14 @@ static void __init xen_banner(void)
 	printk(KERN_INFO "Xen version: %d.%d%s%s\n",
 	       version >> 16, version & 0xffff, extra.extraversion,
 	       xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : "");
+
+#ifdef CONFIG_X86_32
+	pr_warn("WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING!\n"
+		"Support for running as 32-bit PV-guest under Xen will soon be removed\n"
+		"from the Linux kernel!\n"
+		"Please use either a 64-bit kernel or switch to HVM or PVH mode!\n"
+		"WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING!\n");
+#endif
 }
 
 static void __init xen_pv_init_platform(void)