Patches contributed by Eötvös Lorand University


commit 44136717e06b888c2d3129a80abf9ac79233f1eb
Author: Ingo Molnar <mingo@elte.hu>
Date:   Wed Jan 30 13:34:03 2008 +0100

    x86: 64-bit pageattr.c, prepare for unification
    
    Signed-off-by: Ingo Molnar <mingo@elte.hu>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/mm/pageattr_64.c b/arch/x86/mm/pageattr_64.c
index 34acbcd62eb8..190d4d37bc2f 100644
--- a/arch/x86/mm/pageattr_64.c
+++ b/arch/x86/mm/pageattr_64.c
@@ -123,14 +123,15 @@ int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot)
 {
 	int err = 0, kernel_map = 0, i;
 
+#ifdef CONFIG_X86_64
 	if (address >= __START_KERNEL_map &&
 			address < __START_KERNEL_map + KERNEL_TEXT_SIZE) {
 
 		address = (unsigned long)__va(__pa(address));
 		kernel_map = 1;
 	}
+#endif
 
-	down_write(&init_mm.mmap_sem);
 	for (i = 0; i < numpages; i++, address += PAGE_SIZE) {
 		unsigned long pfn = __pa(address) >> PAGE_SHIFT;
 
@@ -139,8 +140,11 @@ int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot)
 			if (err)
 				break;
 		}
-		/* Handle kernel mapping too which aliases part of the
-		 * lowmem */
+#ifdef CONFIG_X86_64
+		/*
+		 * Handle kernel mapping too which aliases part of
+		 * lowmem:
+		 */
 		if (__pa(address) < KERNEL_TEXT_SIZE) {
 			unsigned long addr2;
 			pgprot_t prot2;
@@ -150,8 +154,8 @@ int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot)
 			prot2 = pte_pgprot(pte_mkexec(pfn_pte(0, prot)));
 			err = __change_page_attr(addr2, pfn_to_page(pfn), prot2);
 		}
+#endif
 	}
-	up_write(&init_mm.mmap_sem);
 
 	return err;
 }

commit d9db847f29bec9957c53fbdc05d65c4286235005
Author: Ingo Molnar <mingo@elte.hu>
Date:   Wed Jan 30 13:34:02 2008 +0100

    x86: change 64-bit pageattr to use set_pte_atomic()
    
    NOP change - same as set_pte().
    
    Signed-off-by: Ingo Molnar <mingo@elte.hu>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/mm/pageattr_64.c b/arch/x86/mm/pageattr_64.c
index 5a03fb5fd530..34acbcd62eb8 100644
--- a/arch/x86/mm/pageattr_64.c
+++ b/arch/x86/mm/pageattr_64.c
@@ -86,7 +86,7 @@ __change_page_attr(unsigned long address, struct page *page, pgprot_t prot)
 	prot = canon_pgprot(prot);
 
 	if (level == 4) {
-		set_pte(kpte, mk_pte(page, prot));
+		set_pte_atomic(kpte, mk_pte(page, prot));
 	} else {
 		/*
 		 * split_large_page will take the reference for this
@@ -99,7 +99,7 @@ __change_page_attr(unsigned long address, struct page *page, pgprot_t prot)
 		if (!split)
 			return -ENOMEM;
 		pgprot_val(ref_prot2) &= ~_PAGE_NX;
-		set_pte(kpte, mk_pte(split, ref_prot2));
+		set_pte_atomic(kpte, mk_pte(split, ref_prot2));
 		goto repeat;
 	}
 

commit 0d82494ebd256bfff2336689271367f9284b4865
Author: Ingo Molnar <mingo@elte.hu>
Date:   Wed Jan 30 13:34:02 2008 +0100

    x86: change 64-bit __change_page_attr() to struct page
    
    Signed-off-by: Ingo Molnar <mingo@elte.hu>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/mm/pageattr_64.c b/arch/x86/mm/pageattr_64.c
index 5eff244c16db..5a03fb5fd530 100644
--- a/arch/x86/mm/pageattr_64.c
+++ b/arch/x86/mm/pageattr_64.c
@@ -67,7 +67,7 @@ split_large_page(unsigned long address, pgprot_t ref_prot)
 }
 
 static int
-__change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot)
+__change_page_attr(unsigned long address, struct page *page, pgprot_t prot)
 {
 	struct page *kpte_page;
 	pte_t *kpte;
@@ -86,7 +86,7 @@ __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot)
 	prot = canon_pgprot(prot);
 
 	if (level == 4) {
-		set_pte(kpte, pfn_pte(pfn, prot));
+		set_pte(kpte, mk_pte(page, prot));
 	} else {
 		/*
 		 * split_large_page will take the reference for this
@@ -135,7 +135,7 @@ int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot)
 		unsigned long pfn = __pa(address) >> PAGE_SHIFT;
 
 		if (!kernel_map || pte_present(pfn_pte(0, prot))) {
-			err = __change_page_attr(address, pfn, prot);
+			err = __change_page_attr(address, pfn_to_page(pfn), prot);
 			if (err)
 				break;
 		}
@@ -148,7 +148,7 @@ int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot)
 			addr2 = __START_KERNEL_map + __pa(address);
 			/* Make sure the kernel mappings stay executable */
 			prot2 = pte_pgprot(pte_mkexec(pfn_pte(0, prot)));
-			err = __change_page_attr(addr2, pfn, prot2);
+			err = __change_page_attr(addr2, pfn_to_page(pfn), prot2);
 		}
 	}
 	up_write(&init_mm.mmap_sem);

commit 34eff1d75b26eac5c04f9c5b52ba9e3bf1dd8877
Author: Ingo Molnar <mingo@elte.hu>
Date:   Wed Jan 30 13:34:01 2008 +0100

    x86: simplify __change_page_attr()
    
    Signed-off-by: Ingo Molnar <mingo@elte.hu>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/mm/pageattr_64.c b/arch/x86/mm/pageattr_64.c
index cbded8300e36..5eff244c16db 100644
--- a/arch/x86/mm/pageattr_64.c
+++ b/arch/x86/mm/pageattr_64.c
@@ -67,8 +67,7 @@ split_large_page(unsigned long address, pgprot_t ref_prot)
 }
 
 static int
-__change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot,
-		   pgprot_t ref_prot)
+__change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot)
 {
 	struct page *kpte_page;
 	pte_t *kpte;
@@ -84,32 +83,24 @@ __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot,
 	oldprot = pte_pgprot(*kpte);
 	BUG_ON(PageLRU(kpte_page));
 	BUG_ON(PageCompound(kpte_page));
-	ref_prot = canon_pgprot(ref_prot);
 	prot = canon_pgprot(prot);
 
-	if (pgprot_val(prot) != pgprot_val(ref_prot)) {
-		if (level == 4) {
-			set_pte(kpte, pfn_pte(pfn, prot));
-		} else {
-			/*
-			 * split_large_page will take the reference for this
-			 * change_page_attr on the split page.
-			 */
-			struct page *split;
-
-			ref_prot2 = pte_pgprot(pte_clrhuge(*kpte));
-			split = split_large_page(address, ref_prot2);
-			if (!split)
-				return -ENOMEM;
-			pgprot_val(ref_prot2) &= ~_PAGE_NX;
-			set_pte(kpte, mk_pte(split, ref_prot2));
-			goto repeat;
-		}
+	if (level == 4) {
+		set_pte(kpte, pfn_pte(pfn, prot));
 	} else {
-		if (level == 4) {
-			set_pte(kpte, pfn_pte(pfn, ref_prot));
-		} else
-			BUG();
+		/*
+		 * split_large_page will take the reference for this
+		 * change_page_attr on the split page.
+		 */
+		struct page *split;
+
+		ref_prot2 = pte_pgprot(pte_clrhuge(*kpte));
+		split = split_large_page(address, ref_prot2);
+		if (!split)
+			return -ENOMEM;
+		pgprot_val(ref_prot2) &= ~_PAGE_NX;
+		set_pte(kpte, mk_pte(split, ref_prot2));
+		goto repeat;
 	}
 
 	return 0;
@@ -144,8 +135,7 @@ int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot)
 		unsigned long pfn = __pa(address) >> PAGE_SHIFT;
 
 		if (!kernel_map || pte_present(pfn_pte(0, prot))) {
-			err = __change_page_attr(address, pfn, prot,
-						PAGE_KERNEL);
+			err = __change_page_attr(address, pfn, prot);
 			if (err)
 				break;
 		}
@@ -158,8 +148,7 @@ int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot)
 			addr2 = __START_KERNEL_map + __pa(address);
 			/* Make sure the kernel mappings stay executable */
 			prot2 = pte_pgprot(pte_mkexec(pfn_pte(0, prot)));
-			err = __change_page_attr(addr2, pfn, prot2,
-						 PAGE_KERNEL_EXEC);
+			err = __change_page_attr(addr2, pfn, prot2);
 		}
 	}
 	up_write(&init_mm.mmap_sem);

commit b65e6390fb99ca93877ffc1c84e93c857f32dafc
Author: Ingo Molnar <mingo@elte.hu>
Date:   Wed Jan 30 13:34:01 2008 +0100

    x86: introduce native_set_pte_atomic() on 64-bit too
    
    Signed-off-by: Ingo Molnar <mingo@elte.hu>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/include/asm-x86/pgtable_64.h b/include/asm-x86/pgtable_64.h
index df1fcbd12e43..223b0032bab5 100644
--- a/include/asm-x86/pgtable_64.h
+++ b/include/asm-x86/pgtable_64.h
@@ -76,6 +76,11 @@ static inline void native_set_pte(pte_t *ptep, pte_t pte)
 	*ptep = pte;
 }
 
+static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte)
+{
+	native_set_pte(ptep, pte);
+}
+
 static inline pte_t native_ptep_get_and_clear(pte_t *xp)
 {
 #ifdef CONFIG_SMP

commit a5c62514885a778016c03dbba833d4ff6786e30c
Author: Ingo Molnar <mingo@elte.hu>
Date:   Wed Jan 30 13:34:00 2008 +0100

    x86: clean up and simplify 64-bit split_large_page()
    
    Signed-off-by: Ingo Molnar <mingo@elte.hu>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/mm/pageattr_64.c b/arch/x86/mm/pageattr_64.c
index 107b03c7113c..cbded8300e36 100644
--- a/arch/x86/mm/pageattr_64.c
+++ b/arch/x86/mm/pageattr_64.c
@@ -46,7 +46,7 @@ pte_t *lookup_address(unsigned long address, int *level)
 }
 
 static struct page *
-split_large_page(unsigned long address, pgprot_t prot, pgprot_t ref_prot)
+split_large_page(unsigned long address, pgprot_t ref_prot)
 {
 	unsigned long addr;
 	struct page *base;
@@ -60,10 +60,9 @@ split_large_page(unsigned long address, pgprot_t prot, pgprot_t ref_prot)
 	address = __pa(address);
 	addr = address & LARGE_PAGE_MASK;
 	pbase = (pte_t *)page_address(base);
-	for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE) {
-		pbase[i] = pfn_pte(addr >> PAGE_SHIFT,
-				   addr == address ? prot : ref_prot);
-	}
+	for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE)
+		pbase[i] = pfn_pte(addr >> PAGE_SHIFT, ref_prot);
+
 	return base;
 }
 
@@ -76,6 +75,7 @@ __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot,
 	pgprot_t ref_prot2, oldprot;
 	int level;
 
+repeat:
 	kpte = lookup_address(address, &level);
 	if (!kpte)
 		return 0;
@@ -98,12 +98,12 @@ __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot,
 			struct page *split;
 
 			ref_prot2 = pte_pgprot(pte_clrhuge(*kpte));
-			split = split_large_page(address, prot, ref_prot2);
+			split = split_large_page(address, ref_prot2);
 			if (!split)
 				return -ENOMEM;
 			pgprot_val(ref_prot2) &= ~_PAGE_NX;
 			set_pte(kpte, mk_pte(split, ref_prot2));
-			kpte_page = split;
+			goto repeat;
 		}
 	} else {
 		if (level == 4) {

commit 5e5224a77eb4c68a982c8096945b0af902f9d655
Author: Ingo Molnar <mingo@elte.hu>
Date:   Wed Jan 30 13:34:00 2008 +0100

    x86: unify header part of pageattr_64.c
    
    Signed-off-by: Ingo Molnar <mingo@elte.hu>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/mm/pageattr_64.c b/arch/x86/mm/pageattr_64.c
index 8493c469f877..107b03c7113c 100644
--- a/arch/x86/mm/pageattr_64.c
+++ b/arch/x86/mm/pageattr_64.c
@@ -19,8 +19,9 @@ void clflush_cache_range(void *addr, int size)
 
 #include <asm/processor.h>
 #include <asm/tlbflush.h>
+#include <asm/sections.h>
 #include <asm/uaccess.h>
-#include <asm/io.h>
+#include <asm/pgalloc.h>
 
 pte_t *lookup_address(unsigned long address, int *level)
 {

commit d6ee09a2a0865f5640592e73ca5da4b06404b200
Author: Ingo Molnar <mingo@elte.hu>
Date:   Wed Jan 30 13:33:59 2008 +0100

    x86: simplify pageattr_64.c
    
    simplify pageattr_64.c.
    
    Signed-off-by: Ingo Molnar <mingo@elte.hu>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/mm/pageattr_64.c b/arch/x86/mm/pageattr_64.c
index 7b734ee5b7fd..8493c469f877 100644
--- a/arch/x86/mm/pageattr_64.c
+++ b/arch/x86/mm/pageattr_64.c
@@ -9,6 +9,14 @@
 #include <linux/slab.h>
 #include <linux/mm.h>
 
+void clflush_cache_range(void *addr, int size)
+{
+	int i;
+
+	for (i = 0; i < size; i += boot_cpu_data.x86_clflush_size)
+		clflush(addr+i);
+}
+
 #include <asm/processor.h>
 #include <asm/tlbflush.h>
 #include <asm/uaccess.h>
@@ -47,12 +55,6 @@ split_large_page(unsigned long address, pgprot_t prot, pgprot_t ref_prot)
 	base = alloc_pages(GFP_KERNEL, 0);
 	if (!base)
 		return NULL;
-	/*
-	 * page_private is used to track the number of entries in
-	 * the page table page have non standard attributes.
-	 */
-	SetPagePrivate(base);
-	page_private(base) = 0;
 
 	address = __pa(address);
 	addr = address & LARGE_PAGE_MASK;
@@ -64,80 +66,13 @@ split_large_page(unsigned long address, pgprot_t prot, pgprot_t ref_prot)
 	return base;
 }
 
-void clflush_cache_range(void *addr, int size)
-{
-	int i;
-
-	for (i = 0; i < size; i += boot_cpu_data.x86_clflush_size)
-		clflush(addr+i);
-}
-
-static void flush_kernel_map(void *arg)
-{
-	struct list_head *l = (struct list_head *)arg;
-	struct page *pg;
-
-	__flush_tlb_all();
-
-	/* When clflush is available always use it because it is
-	   much cheaper than WBINVD. */
-	/* clflush is still broken. Disable for now. */
-	if (1 || !cpu_has_clflush) {
-		wbinvd();
-	} else {
-		list_for_each_entry(pg, l, lru) {
-			void *addr = page_address(pg);
-
-			clflush_cache_range(addr, PAGE_SIZE);
-		}
-	}
-}
-
-static inline void flush_map(struct list_head *l)
-{
-	on_each_cpu(flush_kernel_map, l, 1, 1);
-}
-
-static LIST_HEAD(deferred_pages); /* protected by init_mm.mmap_sem */
-
-static inline void save_page(struct page *fpage)
-{
-	if (!test_and_set_bit(PG_arch_1, &fpage->flags))
-		list_add(&fpage->lru, &deferred_pages);
-}
-
-/*
- * No more special protections in this 2/4MB area - revert to a
- * large page again.
- */
-static void revert_page(unsigned long address, pgprot_t ref_prot)
-{
-	unsigned long pfn;
-	pgd_t *pgd;
-	pud_t *pud;
-	pmd_t *pmd;
-	pte_t large_pte;
-
-	pgd = pgd_offset_k(address);
-	BUG_ON(pgd_none(*pgd));
-	pud = pud_offset(pgd, address);
-	BUG_ON(pud_none(*pud));
-	pmd = pmd_offset(pud, address);
-	BUG_ON(pmd_val(*pmd) & _PAGE_PSE);
-	pfn = (__pa(address) & LARGE_PAGE_MASK) >> PAGE_SHIFT;
-	large_pte = pfn_pte(pfn, ref_prot);
-	large_pte = pte_mkhuge(large_pte);
-
-	set_pte((pte_t *)pmd, large_pte);
-}
-
 static int
 __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot,
 		   pgprot_t ref_prot)
 {
 	struct page *kpte_page;
-	pgprot_t ref_prot2;
 	pte_t *kpte;
+	pgprot_t ref_prot2, oldprot;
 	int level;
 
 	kpte = lookup_address(address, &level);
@@ -145,8 +80,12 @@ __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot,
 		return 0;
 
 	kpte_page = virt_to_page(kpte);
+	oldprot = pte_pgprot(*kpte);
 	BUG_ON(PageLRU(kpte_page));
 	BUG_ON(PageCompound(kpte_page));
+	ref_prot = canon_pgprot(ref_prot);
+	prot = canon_pgprot(prot);
+
 	if (pgprot_val(prot) != pgprot_val(ref_prot)) {
 		if (level == 4) {
 			set_pte(kpte, pfn_pte(pfn, prot));
@@ -165,38 +104,29 @@ __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot,
 			set_pte(kpte, mk_pte(split, ref_prot2));
 			kpte_page = split;
 		}
-		page_private(kpte_page)++;
 	} else {
 		if (level == 4) {
 			set_pte(kpte, pfn_pte(pfn, ref_prot));
-			BUG_ON(page_private(kpte_page) == 0);
-			page_private(kpte_page)--;
 		} else
 			BUG();
 	}
 
-	/* on x86-64 the direct mapping set at boot is not using 4k pages */
-	BUG_ON(PageReserved(kpte_page));
-
-	save_page(kpte_page);
-	if (page_private(kpte_page) == 0)
-		revert_page(address, ref_prot);
 	return 0;
 }
 
-/*
- * Change the page attributes of an page in the linear mapping.
- *
- * This should be used when a page is mapped with a different caching policy
- * than write-back somewhere - some CPUs do not like it when mappings with
- * different caching policies exist. This changes the page attributes of the
- * in kernel linear mapping too.
+/**
+ * change_page_attr_addr - Change page table attributes in linear mapping
+ * @address: Virtual address in linear mapping.
+ * @numpages: Number of pages to change
+ * @prot:    New page table attribute (PAGE_*)
  *
- * The caller needs to ensure that there are no conflicting mappings elsewhere.
- * This function only deals with the kernel linear map.
+ * Change page attributes of a page in the direct mapping. This is a variant
+ * of change_page_attr() that also works on memory holes that do not have
+ * mem_map entry (pfn_valid() is false).
  *
- * Caller must call global_flush_tlb() after this.
+ * See change_page_attr() documentation for more details.
  */
+
 int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot)
 {
 	int err = 0, kernel_map = 0, i;
@@ -236,7 +166,26 @@ int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot)
 	return err;
 }
 
-/* Don't call this for MMIO areas that may not have a mem_map entry */
+/**
+ * change_page_attr - Change page table attributes in the linear mapping.
+ * @page: First page to change
+ * @numpages: Number of pages to change
+ * @prot: New protection/caching type (PAGE_*)
+ *
+ * Returns 0 on success, otherwise a negated errno.
+ *
+ * This should be used when a page is mapped with a different caching policy
+ * than write-back somewhere - some CPUs do not like it when mappings with
+ * different caching policies exist. This changes the page attributes of the
+ * in kernel linear mapping too.
+ *
+ * Caller must call global_flush_tlb() later to make the changes active.
+ *
+ * The caller needs to ensure that there are no conflicting mappings elsewhere
+ * (e.g. in user space) * This function only deals with the kernel linear map.
+ *
+ * For MMIO areas without mem_map use change_page_attr_addr() instead.
+ */
 int change_page_attr(struct page *page, int numpages, pgprot_t prot)
 {
 	unsigned long addr = (unsigned long)page_address(page);
@@ -245,29 +194,22 @@ int change_page_attr(struct page *page, int numpages, pgprot_t prot)
 }
 EXPORT_SYMBOL(change_page_attr);
 
-void global_flush_tlb(void)
+static void flush_kernel_map(void *arg)
 {
-	struct page *pg, *next;
-	struct list_head l;
-
 	/*
-	 * Write-protect the semaphore, to exclude two contexts
-	 * doing a list_replace_init() call in parallel and to
-	 * exclude new additions to the deferred_pages list:
+	 * Flush all to work around Errata in early athlons regarding
+	 * large page flushing.
 	 */
-	down_write(&init_mm.mmap_sem);
-	list_replace_init(&deferred_pages, &l);
-	up_write(&init_mm.mmap_sem);
+	__flush_tlb_all();
 
-	flush_map(&l);
+	if (boot_cpu_data.x86_model >= 4)
+		wbinvd();
+}
 
-	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);
-	}
+void global_flush_tlb(void)
+{
+	BUG_ON(irqs_disabled());
+
+	on_each_cpu(flush_kernel_map, NULL, 1, 1);
 }
 EXPORT_SYMBOL(global_flush_tlb);

commit a5f55035f63cf040b4a7161226ec35520cc10daa
Author: Ingo Molnar <mingo@elte.hu>
Date:   Wed Jan 30 13:33:59 2008 +0100

    x86: prepare for the unification of the cpa code
    
    prepare for the unification of the cpa code, by unifying the
    lookup_address() logic between 32-bit and 64-bit.
    
    Signed-off-by: Ingo Molnar <mingo@elte.hu>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/mm/pageattr_64.c b/arch/x86/mm/pageattr_64.c
index 73dbbb4048e6..7b734ee5b7fd 100644
--- a/arch/x86/mm/pageattr_64.c
+++ b/arch/x86/mm/pageattr_64.c
@@ -19,26 +19,21 @@ pte_t *lookup_address(unsigned long address, int *level)
 	pgd_t *pgd = pgd_offset_k(address);
 	pud_t *pud;
 	pmd_t *pmd;
-	pte_t *pte;
 
 	if (pgd_none(*pgd))
 		return NULL;
 	pud = pud_offset(pgd, address);
-	if (!pud_present(*pud))
+	if (pud_none(*pud))
 		return NULL;
 	pmd = pmd_offset(pud, address);
-	if (!pmd_present(*pmd))
+	if (pmd_none(*pmd))
 		return NULL;
 	*level = 3;
 	if (pmd_large(*pmd))
 		return (pte_t *)pmd;
 	*level = 4;
 
-	pte = pte_offset_kernel(pmd, address);
-	if (pte && !pte_present(*pte))
-		pte = NULL;
-
-	return pte;
+	return pte_offset_kernel(pmd, address);
 }
 
 static struct page *

commit bbb09f5cfcde7e4cf1466111d671ac4a62931148
Author: Ingo Molnar <mingo@elte.hu>
Date:   Wed Jan 30 13:33:59 2008 +0100

    x86: prepare for the unification of the cpa code
    
    prepare for the unification of the cpa code, by unifying the
    lookup_address() logic between 32-bit and 64-bit.
    
    Signed-off-by: Ingo Molnar <mingo@elte.hu>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/mm/pageattr-test.c b/arch/x86/mm/pageattr-test.c
index 0dce0e248a42..6cc106b388a5 100644
--- a/arch/x86/mm/pageattr-test.c
+++ b/arch/x86/mm/pageattr-test.c
@@ -20,10 +20,10 @@ enum {
 	LOWEST_LEVEL		= 4,
 	LPS			= (1 << PMD_SHIFT),
 #elif defined(CONFIG_X86_PAE)
-	LOWEST_LEVEL		= 3,
+	LOWEST_LEVEL		= 4,
 	LPS			= (1 << PMD_SHIFT),
 #else
-	LOWEST_LEVEL		= 3, /* lookup_address lies here */
+	LOWEST_LEVEL		= 4, /* lookup_address lies here */
 	LPS			= (1 << 22),
 #endif
 	GPS			= (1<<30)
diff --git a/arch/x86/mm/pageattr_32.c b/arch/x86/mm/pageattr_32.c
index dd49b16b3a0e..1c7bd81a4194 100644
--- a/arch/x86/mm/pageattr_32.c
+++ b/arch/x86/mm/pageattr_32.c
@@ -29,10 +29,10 @@ pte_t *lookup_address(unsigned long address, int *level)
 	pmd = pmd_offset(pud, address);
 	if (pmd_none(*pmd))
 		return NULL;
-	*level = 2;
+	*level = 3;
 	if (pmd_large(*pmd))
 		return (pte_t *)pmd;
-	*level = 3;
+	*level = 4;
 
 	return pte_offset_kernel(pmd, address);
 }
@@ -136,7 +136,7 @@ static int __change_page_attr(struct page *page, pgprot_t prot)
 		address < (unsigned long)&_etext &&
 	       (pgprot_val(prot) & _PAGE_NX));
 
-	if (level == 3) {
+	if (level == 4) {
 		set_pte_atomic(kpte, mk_pte(page, canon_pgprot(prot)));
 	} else {
 		err = split_large_page(kpte, address);