x86: return the page table level in lookup_address()

based on this patch from Andi Kleen:

|  Subject: CPA: Return the page table level in lookup_address()
|  From: Andi Kleen <ak@suse.de>
|
|  Needed for the next change.
|
|  And change all the callers.

and ported it to x86.git.

Signed-off-by: Andi Kleen <ak@suse.de>
Acked-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/mm/fault_32.c

@@ -613,7 +613,8 @@ no_context:
 
 #ifdef CONFIG_X86_PAE
 		if (error_code & PF_INSTR) {
-			pte_t *pte = lookup_address(address);
+			int level;
+			pte_t *pte = lookup_address(address, &level);
 
 			if (pte && pte_present(*pte) && !pte_exec(*pte))
 				printk(KERN_CRIT "kernel tried to execute "

arch/x86/mm/init_32.c

@@ -535,11 +535,12 @@ int __init set_kernel_exec(unsigned long vaddr, int enable)
 {
 	pte_t *pte;
 	int ret = 1;
+	int level;
 
 	if (!nx_enabled)
 		goto out;
 
-	pte = lookup_address(vaddr);
+	pte = lookup_address(vaddr, &level);
 	BUG_ON(!pte);
 
 	if (!pte_exec(*pte))

arch/x86/mm/pageattr_32.c

@@ -18,7 +18,7 @@
 static DEFINE_SPINLOCK(cpa_lock);
 static struct list_head df_list = LIST_HEAD_INIT(df_list);
 
-pte_t *lookup_address(unsigned long address)
+pte_t *lookup_address(unsigned long address, int *level)
 {
 	pgd_t *pgd = pgd_offset_k(address);
 	pud_t *pud;
@@ -32,8 +32,10 @@ pte_t *lookup_address(unsigned long address)
 	pmd = pmd_offset(pud, address);
 	if (pmd_none(*pmd))
 		return NULL;
+	*level = 2;
 	if (pmd_large(*pmd))
 		return (pte_t *)pmd;
+	*level = 3;
 
 	return pte_offset_kernel(pmd, address);
 }
@@ -156,11 +158,12 @@ static int __change_page_attr(struct page *page, pgprot_t prot)
 	struct page *kpte_page;
 	unsigned long address;
 	pte_t *kpte;
+	int level;
 
 	BUG_ON(PageHighMem(page));
 	address = (unsigned long)page_address(page);
 
-	kpte = lookup_address(address);
+	kpte = lookup_address(address, &level);
 	if (!kpte)
 		return -EINVAL;
 

arch/x86/mm/pageattr_64.c

@@ -14,7 +14,7 @@
 #include <asm/uaccess.h>
 #include <asm/io.h>
 
-pte_t *lookup_address(unsigned long address)
+pte_t *lookup_address(unsigned long address, int *level)
 {
 	pgd_t *pgd = pgd_offset_k(address);
 	pud_t *pud;
@@ -29,8 +29,10 @@ pte_t *lookup_address(unsigned long address)
 	pmd = pmd_offset(pud, address);
 	if (!pmd_present(*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))
@@ -140,8 +142,9 @@ __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot,
 	struct page *kpte_page;
 	pgprot_t ref_prot2;
 	pte_t *kpte;
+	int level;
 
-	kpte = lookup_address(address);
+	kpte = lookup_address(address, &level);
 	if (!kpte)
 		return 0;
 

arch/x86/xen/mmu.c

@@ -58,7 +58,8 @@
 
 xmaddr_t arbitrary_virt_to_machine(unsigned long address)
 {
-	pte_t *pte = lookup_address(address);
+	int level;
+	pte_t *pte = lookup_address(address, &level);
 	unsigned offset = address & PAGE_MASK;
 
 	BUG_ON(pte == NULL);
@@ -70,8 +71,9 @@ void make_lowmem_page_readonly(void *vaddr)
 {
 	pte_t *pte, ptev;
 	unsigned long address = (unsigned long)vaddr;
+	int level;
 
-	pte = lookup_address(address);
+	pte = lookup_address(address, &level);
 	BUG_ON(pte == NULL);
 
 	ptev = pte_wrprotect(*pte);
@@ -84,8 +86,9 @@ void make_lowmem_page_readwrite(void *vaddr)
 {
 	pte_t *pte, ptev;
 	unsigned long address = (unsigned long)vaddr;
+	int level;
 
-	pte = lookup_address(address);
+	pte = lookup_address(address, &level);
 	BUG_ON(pte == NULL);
 
 	ptev = pte_mkwrite(*pte);

include/asm-x86/pgtable_32.h

@@ -182,7 +182,7 @@ static inline void clone_pgd_range(pgd_t *dst, pgd_t *src, int count)
  * NOTE: the return type is pte_t but if the pmd is PSE then we return it
  * as a pte too.
  */
-extern pte_t *lookup_address(unsigned long address);
+extern pte_t *lookup_address(unsigned long address, int *level);
 
 /*
  * Make a given kernel text page executable/non-executable.

include/asm-x86/pgtable_64.h

@@ -240,7 +240,7 @@ extern struct list_head pgd_list;
 
 extern int kern_addr_valid(unsigned long addr); 
 
-pte_t *lookup_address(unsigned long addr);
+pte_t *lookup_address(unsigned long addr, int *level);
 
 #define io_remap_pfn_range(vma, vaddr, pfn, size, prot)		\
 		remap_pfn_range(vma, vaddr, pfn, size, prot)