x86: Always flush pages in change_page_attr

Fix a bug introduced with the CLFLUSH changes: we must always flush pages
changed in cpa(), not just when they are reverted.

Reenable CLFLUSH usage with that now (it was temporarily disabled
for .22)

Add some BUG_ONs

Contains fixes from  Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 3 deletions

diff --git a/arch/i386/mm/pageattr.c b/arch/i386/mm/pageattr.c
index 37992ffb1633..8927222b3ab2 100644
--- a/arch/i386/mm/pageattr.c
+++ b/arch/i386/mm/pageattr.c
@@ -82,7 +82,7 @@ static void flush_kernel_map(void *arg)
         struct page *p;
 
         /* High level code is not ready for clflush yet */
-        if (0 && cpu_has_clflush) {
+        if (cpu_has_clflush) {
                 list_for_each_entry (p, lh, lru)
                         cache_flush_page(p);
         } else if (boot_cpu_data.x86_model >= 4)
@@ -136,6 +136,12 @@ static inline void revert_page(struct page *kpte_page, unsigned long address)
                             ref_prot));
 }
 
+static inline void save_page(struct page *kpte_page)
+{
+        if (!test_and_set_bit(PG_arch_1, &kpte_page->flags))
+                list_add(&kpte_page->lru, &df_list);
+}
+
 static int
 __change_page_attr(struct page *page, pgprot_t prot)
 { 
@@ -150,6 +156,9 @@ __change_page_attr(struct page *page, pgprot_t prot)
         if (!kpte)
                 return -EINVAL;
         kpte_page = virt_to_page(kpte);
+        BUG_ON(PageLRU(kpte_page));
+        BUG_ON(PageCompound(kpte_page));
+
         if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL)) { 
                 if (!pte_huge(*kpte)) {
                         set_pte_atomic(kpte, mk_pte(page, prot)); 
@@ -179,11 +188,11 @@ __change_page_attr(struct page *page, pgprot_t prot)
          * time (not via split_large_page) and in turn we must not
          * replace it with a largepage.
          */
+
+        save_page(kpte_page);
         if (!PageReserved(kpte_page)) {
                 if (cpu_has_pse && (page_private(kpte_page) == 0)) {
-                        ClearPagePrivate(kpte_page);
                         paravirt_release_pt(page_to_pfn(kpte_page));
-                        list_add(&kpte_page->lru, &df_list);
                         revert_page(kpte_page, address);
                 }
         }
@@ -236,6 +245,11 @@ void global_flush_tlb(void)
         spin_unlock_irq(&cpa_lock);
         flush_map(&l);
         list_for_each_entry_safe(pg, next, &l, lru) {
+                list_del(&pg->lru);
+                clear_bit(PG_arch_1, &pg->flags);
+                if (PageReserved(pg) || !cpu_has_pse || page_private(pg) != 0)
+                        continue;
+                ClearPagePrivate(pg);
                 __free_page(pg);
         }
 }