x86/tboot: Mark tboot static

This structure is only really used in tboot.c.  The only exception
is a single tboot_enabled check, but for that we don't need an inline
function.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200428051703.1625952-1-hch@lst.de

arch/x86/kernel/tboot.c

@@ -35,8 +35,7 @@
 #include "../realmode/rm/wakeup.h"
 
 /* Global pointer to shared data; NULL means no measured launch. */
-struct tboot *tboot __read_mostly;
-EXPORT_SYMBOL(tboot);
+static struct tboot *tboot __read_mostly;
 
 /* timeout for APs (in secs) to enter wait-for-SIPI state during shutdown */
 #define AP_WAIT_TIMEOUT		1
@@ -46,6 +45,11 @@ EXPORT_SYMBOL(tboot);
 
 static u8 tboot_uuid[16] __initdata = TBOOT_UUID;
 
+bool tboot_enabled(void)
+{
+	return tboot != NULL;
+}
+
 void __init tboot_probe(void)
 {
 	/* Look for valid page-aligned address for shared page. */

include/linux/tboot.h

@@ -121,13 +121,7 @@ struct tboot {
 #define TBOOT_UUID	{0xff, 0x8d, 0x3c, 0x66, 0xb3, 0xe8, 0x82, 0x4b, 0xbf,\
 			 0xaa, 0x19, 0xea, 0x4d, 0x5, 0x7a, 0x8}
 
-extern struct tboot *tboot;
-
-static inline int tboot_enabled(void)
-{
-	return tboot != NULL;
-}
-
+bool tboot_enabled(void);
 extern void tboot_probe(void);
 extern void tboot_shutdown(u32 shutdown_type);
 extern struct acpi_table_header *tboot_get_dmar_table(