2 files changed, 14 insertions, 11 deletions

diff --git a/arch/i386/mm/highmem.c b/arch/i386/mm/highmem.c
index ba44000b9069..f9f647cdbc7b 100644
--- a/arch/i386/mm/highmem.c
+++ b/arch/i386/mm/highmem.c
@@ -38,22 +38,19 @@ void *kmap_atomic(struct page *page, enum km_type type)
 
         idx = type + KM_TYPE_NR*smp_processor_id();
         vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
-#ifdef CONFIG_DEBUG_HIGHMEM
         if (!pte_none(*(kmap_pte-idx)))
                 BUG();
-#endif
         set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
-        __flush_tlb_one(vaddr);
 
         return (void*) vaddr;
 }
 
 void kunmap_atomic(void *kvaddr, enum km_type type)
 {
-#ifdef CONFIG_DEBUG_HIGHMEM
         unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
         enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
 
+#ifdef CONFIG_DEBUG_HIGHMEM
         if (vaddr >= PAGE_OFFSET && vaddr < (unsigned long)high_memory) {
                 dec_preempt_count();
                 preempt_check_resched();
@@ -62,14 +59,14 @@ void kunmap_atomic(void *kvaddr, enum km_type type)
 
         if (vaddr != __fix_to_virt(FIX_KMAP_BEGIN+idx))
                 BUG();
-
+#endif
         /*
-         * force other mappings to Oops if they'll try to access
-         * this pte without first remap it
+         * Force other mappings to Oops if they'll try to access this pte
+         * without first remap it.  Keeping stale mappings around is a bad idea
+         * also, in case the page changes cacheability attributes or becomes
+         * a protected page in a hypervisor.
          */
-        pte_clear(&init_mm, vaddr, kmap_pte-idx);
-        __flush_tlb_one(vaddr);
-#endif
+        kpte_clear_flush(kmap_pte-idx, vaddr);
 
         dec_preempt_count();
         preempt_check_resched();
@@ -88,7 +85,6 @@ void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
         idx = type + KM_TYPE_NR*smp_processor_id();
         vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
         set_pte(kmap_pte-idx, pfn_pte(pfn, kmap_prot));
-        __flush_tlb_one(vaddr);
 
         return (void*) vaddr;
 }
diff --git a/include/asm-i386/pgtable.h b/include/asm-i386/pgtable.h
index 94c87ff4b5ac..ee9696d2f67f 100644
--- a/include/asm-i386/pgtable.h
+++ b/include/asm-i386/pgtable.h
@@ -441,6 +441,13 @@ extern pte_t *lookup_address(unsigned long address);
 #define pte_unmap_nested(pte) do { } while (0)
 #endif
 
+/* Clear a kernel PTE and flush it from the TLB */
+#define kpte_clear_flush(ptep, vaddr)                                   \
+do {                                                                    \
+        pte_clear(&init_mm, vaddr, ptep);                               \
+        __flush_tlb_one(vaddr);                                         \
+} while (0)
+
 /*
  * The i386 doesn't have any external MMU info: the kernel page
  * tables contain all the necessary information.