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, 14 insertions, 9 deletions

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);
         }