patch-2_6_7-vs1_9_1_12

[linux-2.6.git] / arch / x86_64 / mm / pageattr.c

diff --git a/arch/x86_64/mm/pageattr.c b/arch/x86_64/mm/pageattr.c
index c91b22c..5507708 100644 (file)
--- a/arch/x86_64/mm/pageattr.c
+++ b/arch/x86_64/mm/pageattr.c
@@ -32,7 +32,8 @@ static inline pte_t *lookup_address(unsigned long address)
        return pte;
 } 
 
-static struct page *split_large_page(unsigned long address, pgprot_t prot)
+static struct page *split_large_page(unsigned long address, pgprot_t prot,
+                                    pgprot_t ref_prot)
 { 
        int i; 
        unsigned long addr;
@@ -45,7 +46,7 @@ static struct page *split_large_page(unsigned long address, pgprot_t prot)
        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 : PAGE_KERNEL);
+                                  addr == address ? prot : ref_prot);
        }
        return base;
 } 
@@ -95,7 +96,7 @@ static inline void save_page(unsigned long address, struct page *fpage)
  * No more special protections in this 2/4MB area - revert to a
  * large page again. 
  */
-static void revert_page(struct page *kpte_page, unsigned long address)
+static void revert_page(unsigned long address, pgprot_t ref_prot)
 {
        pgd_t *pgd;
        pmd_t *pmd; 
@@ -104,12 +105,14 @@ static void revert_page(struct page *kpte_page, unsigned long address)
        pgd = pgd_offset_k(address); 
        pmd = pmd_offset(pgd, address);
        BUG_ON(pmd_val(*pmd) & _PAGE_PSE); 
-       large_pte = mk_pte_phys(__pa(address) & LARGE_PAGE_MASK, PAGE_KERNEL_LARGE);
+       pgprot_val(ref_prot) |= _PAGE_PSE;
+       large_pte = mk_pte_phys(__pa(address) & LARGE_PAGE_MASK, ref_prot);
        set_pte((pte_t *)pmd, large_pte);
 }      
 
 static int
-__change_page_attr(unsigned long address, struct page *page, pgprot_t prot)
+__change_page_attr(unsigned long address, struct page *page, pgprot_t prot, 
+                  pgprot_t ref_prot)
 { 
        pte_t *kpte; 
        struct page *kpte_page;
@@ -119,29 +122,29 @@ __change_page_attr(unsigned long address, struct page *page, pgprot_t prot)
        if (!kpte) return 0;
        kpte_page = virt_to_page(((unsigned long)kpte) & PAGE_MASK);
        kpte_flags = pte_val(*kpte); 
-       if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL)) { 
+       if (pgprot_val(prot) != pgprot_val(ref_prot)) { 
                if ((kpte_flags & _PAGE_PSE) == 0) { 
                        pte_t old = *kpte;
-                       pte_t standard = mk_pte(page, PAGE_KERNEL); 
+                       pte_t standard = mk_pte(page, ref_prot); 
 
                        set_pte(kpte, mk_pte(page, prot)); 
                        if (pte_same(old,standard))
-                               atomic_inc(&kpte_page->count);
+                               get_page(kpte_page);
                } else {
-                       struct page *split = split_large_page(address, prot); 
+                       struct page *split = split_large_page(address, prot, ref_prot); 
                        if (!split)
                                return -ENOMEM;
-                       atomic_inc(&kpte_page->count);
-                       set_pte(kpte,mk_pte(split, PAGE_KERNEL));
+                       get_page(kpte_page);
+                       set_pte(kpte,mk_pte(split, ref_prot));
                }       
        } else if ((kpte_flags & _PAGE_PSE) == 0) { 
-               set_pte(kpte, mk_pte(page, PAGE_KERNEL));
-               atomic_dec(&kpte_page->count); 
+               set_pte(kpte, mk_pte(page, ref_prot));
+               __put_page(kpte_page);
        }
 
-       if (atomic_read(&kpte_page->count) == 1) { 
+       if (page_count(kpte_page) == 1) {
                save_page(address, kpte_page);               
-               revert_page(kpte_page, address);
+               revert_page(address, ref_prot);
        } 
        return 0;
 } 
@@ -167,13 +170,17 @@ int change_page_attr(struct page *page, int numpages, pgprot_t prot)
        down_write(&init_mm.mmap_sem);
        for (i = 0; i < numpages; !err && i++, page++) { 
                unsigned long address = (unsigned long)page_address(page); 
-               err = __change_page_attr(address, page, prot); 
+               err = __change_page_attr(address, page, prot, PAGE_KERNEL); 
                if (err) 
                        break; 
-               /* Handle kernel mapping too which aliases part of the lowmem */
-               if (page_to_phys(page) < KERNEL_TEXT_SIZE) {            
-                       unsigned long addr2 = __START_KERNEL_map + page_to_phys(page);
-                       err = __change_page_attr(addr2, page, prot);
+               /* Handle kernel mapping too which aliases part of the
+                * lowmem */
+               /* Disabled right now. Fixme */ 
+               if (0 && page_to_phys(page) < KERNEL_TEXT_SIZE) {               
+                       unsigned long addr2;
+                       addr2 = __START_KERNEL_map + page_to_phys(page);
+                       err = __change_page_attr(addr2, page, prot, 
+                                                PAGE_KERNEL_EXECUTABLE);
                } 
        }       
        up_write(&init_mm.mmap_sem);