x86: make sure the CPA test code's use of _PAGE_UNUSED1 is obvious

The CPA test code uses _PAGE_UNUSED1, so make sure its obvious.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/mm/pageattr-test.c

@@ -32,7 +32,7 @@ enum {
 	GPS			= (1<<30)
 };
 
-#define PAGE_TESTBIT	__pgprot(_PAGE_UNUSED1)
+#define PAGE_CPA_TEST	__pgprot(_PAGE_CPA_TEST)
 
 static int pte_testbit(pte_t pte)
 {
@@ -174,7 +174,7 @@ static int pageattr_test(void)
 		}
 
 		test_addr = addr[i];
-		err = change_page_attr_set(&test_addr, len[i], PAGE_TESTBIT, 0);
+		err = change_page_attr_set(&test_addr, len[i], PAGE_CPA_TEST, 0);
 		if (err < 0) {
 			printk(KERN_ERR "CPA %d failed %d\n", i, err);
 			failed++;
@@ -207,7 +207,7 @@ static int pageattr_test(void)
 			continue;
 		}
 		test_addr = addr[i];
-		err = change_page_attr_clear(&test_addr, len[i], PAGE_TESTBIT, 0);
+		err = change_page_attr_clear(&test_addr, len[i], PAGE_CPA_TEST, 0);
 		if (err < 0) {
 			printk(KERN_ERR "CPA reverting failed: %d\n", err);
 			failed++;

include/asm-x86/pgtable.h

@@ -19,6 +19,7 @@
 #define _PAGE_BIT_UNUSED3	11
 #define _PAGE_BIT_PAT_LARGE	12	/* On 2MB or 1GB pages */
 #define _PAGE_BIT_SPECIAL	_PAGE_BIT_UNUSED1
+#define _PAGE_BIT_CPA_TEST	_PAGE_BIT_UNUSED1
 #define _PAGE_BIT_NX           63       /* No execute: only valid after cpuid check */
 
 #define _PAGE_PRESENT	(_AT(pteval_t, 1) << _PAGE_BIT_PRESENT)
@@ -36,6 +37,7 @@
 #define _PAGE_PAT	(_AT(pteval_t, 1) << _PAGE_BIT_PAT)
 #define _PAGE_PAT_LARGE (_AT(pteval_t, 1) << _PAGE_BIT_PAT_LARGE)
 #define _PAGE_SPECIAL	(_AT(pteval_t, 1) << _PAGE_BIT_SPECIAL)
+#define _PAGE_CPA_TEST	(_AT(pteval_t, 1) << _PAGE_BIT_CPA_TEST)
 #define __HAVE_ARCH_PTE_SPECIAL
 
 #if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)