---

yaml
---
r: 37737
b: refs/heads/master
c: 23002d8
h: refs/heads/master
i:
  37735: 665a004
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 25e4df5bae333a06cd2c9b88baf14432652dc9f7
+refs/heads/master: 23002d88be309a7c78db69363c9d933a29a3b0bb

trunk/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;
 }

trunk/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.