x86/cpa: use an undefined PTE bit for testing CPA
Rather than using _PAGE_GLOBAL - which not all CPUs support - to test
CPA, use one of the reserved-for-software-use PTE flags instead. This
allows CPA testing to work on CPUs which don't support PGD.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/mm/pageattr-test.c b/arch/x86/mm/pageattr-test.c
index 75f1b10..0dcd42e 100644
--- a/arch/x86/mm/pageattr-test.c
+++ b/arch/x86/mm/pageattr-test.c
@@ -1,8 +1,8 @@
/*
* self test for change_page_attr.
*
- * Clears the global bit on random pages in the direct mapping, then reverts
- * and compares page tables forwards and afterwards.
+ * Clears the a test pte bit on random pages in the direct mapping,
+ * then reverts and compares page tables forwards and afterwards.
*/
#include <linux/bootmem.h>
#include <linux/kthread.h>
@@ -32,6 +32,13 @@
GPS = (1<<30)
};
+#define PAGE_TESTBIT __pgprot(_PAGE_UNUSED1)
+
+static int pte_testbit(pte_t pte)
+{
+ return pte_flags(pte) & _PAGE_UNUSED1;
+}
+
struct split_state {
long lpg, gpg, spg, exec;
long min_exec, max_exec;
@@ -165,15 +172,14 @@
continue;
}
- err = change_page_attr_clear(addr[i], len[i],
- __pgprot(_PAGE_GLOBAL));
+ err = change_page_attr_set(addr[i], len[i], PAGE_TESTBIT);
if (err < 0) {
printk(KERN_ERR "CPA %d failed %d\n", i, err);
failed++;
}
pte = lookup_address(addr[i], &level);
- if (!pte || pte_global(*pte) || pte_huge(*pte)) {
+ if (!pte || !pte_testbit(*pte) || pte_huge(*pte)) {
printk(KERN_ERR "CPA %lx: bad pte %Lx\n", addr[i],
pte ? (u64)pte_val(*pte) : 0ULL);
failed++;
@@ -198,14 +204,13 @@
failed++;
continue;
}
- err = change_page_attr_set(addr[i], len[i],
- __pgprot(_PAGE_GLOBAL));
+ err = change_page_attr_clear(addr[i], len[i], PAGE_TESTBIT);
if (err < 0) {
printk(KERN_ERR "CPA reverting failed: %d\n", err);
failed++;
}
pte = lookup_address(addr[i], &level);
- if (!pte || !pte_global(*pte)) {
+ if (!pte || pte_testbit(*pte)) {
printk(KERN_ERR "CPA %lx: bad pte after revert %Lx\n",
addr[i], pte ? (u64)pte_val(*pte) : 0ULL);
failed++;