KPTI: Report when enabled

CVE-2017-5754

Make sure dmesg reports when KPTI is enabled.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

arch/x86/mm/kaiser.c

@@ -11,6 +11,9 @@
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
 
+#undef pr_fmt
+#define pr_fmt(fmt)     "Kernel/User page tables isolation: " fmt
+
 #include <asm/kaiser.h>
 #include <asm/tlbflush.h>	/* to verify its kaiser declarations */
 #include <asm/pgtable.h>
@@ -293,7 +296,7 @@ void __init kaiser_check_boottime_disable(void)
 	return;
 
 disable:
-	pr_info("Kernel/User page tables isolation: disabled\n");
+	pr_info("disabled\n");
 
 silent_disable:
 	kaiser_enabled = 0;
@@ -353,6 +356,8 @@ void __init kaiser_init(void)
 	kaiser_add_user_map_early(&debug_idt_table,
 				  sizeof(gate_desc) * NR_VECTORS,
 				  __PAGE_KERNEL);
+
+	pr_info("enabled\n");
 }
 
 /* Add a mapping to the shadow mapping, and synchronize the mappings */