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>

2 files changed, 31 insertions, 12 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);
         }
 }
diff --git a/arch/x86_64/mm/pageattr.c b/arch/x86_64/mm/pageattr.c
index 9148f4a4cec6..36377b6b8efe 100644
--- a/arch/x86_64/mm/pageattr.c
+++ b/arch/x86_64/mm/pageattr.c
@@ -74,14 +74,12 @@ static void flush_kernel_map(void *arg)
         struct page *pg;
 
         /* When clflush is available always use it because it is
-           much cheaper than WBINVD. Disable clflush for now because
-           the high level code is not ready yet */
-        if (1 || !cpu_has_clflush)
+           much cheaper than WBINVD. */
+        if (!cpu_has_clflush)
                 asm volatile("wbinvd" ::: "memory");
         else list_for_each_entry(pg, l, lru) {
                 void *adr = page_address(pg);
-                if (cpu_has_clflush)
-                        cache_flush_page(adr);
+                cache_flush_page(adr);
         }
         __flush_tlb_all();
 }
@@ -95,7 +93,8 @@ static LIST_HEAD(deferred_pages); /* protected by init_mm.mmap_sem */
 
 static inline void save_page(struct page *fpage)
 {
-        list_add(&fpage->lru, &deferred_pages);
+        if (!test_and_set_bit(PG_arch_1, &fpage->flags))
+                list_add(&fpage->lru, &deferred_pages);
 }
 
 /* 
@@ -129,9 +128,12 @@ __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot,
         pte_t *kpte; 
         struct page *kpte_page;
         pgprot_t ref_prot2;
+
         kpte = lookup_address(address);
         if (!kpte) return 0;
         kpte_page = virt_to_page(((unsigned long)kpte) & PAGE_MASK);
+        BUG_ON(PageLRU(kpte_page));
+        BUG_ON(PageCompound(kpte_page));
         if (pgprot_val(prot) != pgprot_val(ref_prot)) { 
                 if (!pte_huge(*kpte)) {
                         set_pte(kpte, pfn_pte(pfn, prot));
@@ -159,10 +161,9 @@ __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot,
         /* on x86-64 the direct mapping set at boot is not using 4k pages */
         BUG_ON(PageReserved(kpte_page));
 
-        if (page_private(kpte_page) == 0) {
-                save_page(kpte_page);
+        save_page(kpte_page);
+        if (page_private(kpte_page) == 0)
                 revert_page(address, ref_prot);
-        }
         return 0;
 } 
 
@@ -234,6 +235,10 @@ void global_flush_tlb(void)
         flush_map(&l);
 
         list_for_each_entry_safe(pg, next, &l, lru) {
+                list_del(&pg->lru);
+                clear_bit(PG_arch_1, &pg->flags);
+                if (page_private(pg) != 0)
+                        continue;
                 ClearPagePrivate(pg);
                 __free_page(pg);
         }