]> pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - arch/x86/mm/pageattr_32.c
x86: c_p_a() make it more robust against use of PAT bits
[linux-2.6-omap-h63xx.git] / arch / x86 / mm / pageattr_32.c
index 4241a74d16c8d3181256b9ed7b0c688edb2bfe85..66688a630839ef6e6c6593644ca61d4952ffc692 100644 (file)
@@ -1,28 +1,29 @@
-/* 
- * Copyright 2002 Andi Kleen, SuSE Labs. 
+/*
+ * Copyright 2002 Andi Kleen, SuSE Labs.
  * Thanks to Ben LaHaise for precious feedback.
- */ 
+ */
 
-#include <linux/mm.h>
-#include <linux/sched.h>
 #include <linux/highmem.h>
 #include <linux/module.h>
+#include <linux/sched.h>
 #include <linux/slab.h>
-#include <asm/uaccess.h>
+#include <linux/mm.h>
+
 #include <asm/processor.h>
 #include <asm/tlbflush.h>
-#include <asm/pgalloc.h>
 #include <asm/sections.h>
+#include <asm/uaccess.h>
+#include <asm/pgalloc.h>
 
 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;
        pmd_t *pmd;
+
        if (pgd_none(*pgd))
                return NULL;
        pud = pud_offset(pgd, address);
@@ -31,23 +32,26 @@ 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;
-        return pte_offset_kernel(pmd, address);
-} 
+       *level = 3;
 
-static struct page *split_large_page(unsigned long address, pgprot_t prot,
-                                       pgprot_t ref_prot)
-{ 
-       int i; 
+       return pte_offset_kernel(pmd, address);
+}
+
+static struct page *
+split_large_page(unsigned long address, pgprot_t prot, pgprot_t ref_prot)
+{
        unsigned long addr;
        struct page *base;
        pte_t *pbase;
+       int i;
 
        spin_unlock_irq(&cpa_lock);
        base = alloc_pages(GFP_KERNEL, 0);
        spin_lock_irq(&cpa_lock);
-       if (!base) 
+       if (!base)
                return NULL;
 
        /*
@@ -58,22 +62,24 @@ static struct page *split_large_page(unsigned long address, pgprot_t prot,
        page_private(base) = 0;
 
        address = __pa(address);
-       addr = address & LARGE_PAGE_MASK; 
+       addr = address & LARGE_PAGE_MASK;
        pbase = (pte_t *)page_address(base);
        paravirt_alloc_pt(&init_mm, page_to_pfn(base));
+
        for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE) {
-               set_pte(&pbase[i], pfn_pte(addr >> PAGE_SHIFT,
-                                          addr == address ? prot : ref_prot));
+               set_pte(&pbase[i], pfn_pte(addr >> PAGE_SHIFT,
+                                          addr == address ? prot : ref_prot));
        }
        return base;
-} 
+}
 
 static void cache_flush_page(struct page *p)
-{ 
-       unsigned long adr = (unsigned long)page_address(p);
+{
+       void *addr = page_address(p);
        int i;
+
        for (i = 0; i < PAGE_SIZE; i += boot_cpu_data.x86_clflush_size)
-               asm volatile("clflush (%0)" :: "r" (adr + i));
+               clflush(addr + i);
 }
 
 static void flush_kernel_map(void *arg)
@@ -81,25 +87,29 @@ static void flush_kernel_map(void *arg)
        struct list_head *lh = (struct list_head *)arg;
        struct page *p;
 
+       /*
+        * Flush all to work around Errata in early athlons regarding
+        * large page flushing.
+        */
+       __flush_tlb_all();
+
        /* High level code is not ready for clflush yet */
        if (0 && cpu_has_clflush) {
-               list_for_each_entry (p, lh, lru)
+               list_for_each_entry(p, lh, lru)
                        cache_flush_page(p);
-       } else if (boot_cpu_data.x86_model >= 4)
-               wbinvd();
-
-       /* Flush all to work around Errata in early athlons regarding 
-        * large page flushing. 
-        */
-       __flush_tlb_all();      
+       } else {
+               if (boot_cpu_data.x86_model >= 4)
+                       wbinvd();
+       }
 }
 
-static void set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte) 
-{ 
-       struct page *page;
+static void set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
+{
        unsigned long flags;
+       struct page *page;
 
-       set_pte_atomic(kpte, pte);      /* change init_mm */
+       /* change init_mm */
+       set_pte_atomic(kpte, pte);
        if (SHARED_KERNEL_PMD)
                return;
 
@@ -108,6 +118,7 @@ static void set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
                pgd_t *pgd;
                pud_t *pud;
                pmd_t *pmd;
+
                pgd = (pgd_t *)page_address(page) + pgd_index(address);
                pud = pud_offset(pgd, address);
                pmd = pmd_offset(pud, address);
@@ -116,9 +127,9 @@ static void set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
        spin_unlock_irqrestore(&pgd_lock, flags);
 }
 
-/* 
- * No more special protections in this 2/4MB area - revert to a
- * large page again. 
+/*
+ * No more special protections in this 2/4MB area - revert to a large
+ * page again.
  */
 static inline void revert_page(struct page *kpte_page, unsigned long address)
 {
@@ -142,29 +153,30 @@ static inline void save_page(struct page *kpte_page)
                list_add(&kpte_page->lru, &df_list);
 }
 
-static int
-__change_page_attr(struct page *page, pgprot_t prot)
-{ 
-       pte_t *kpte; 
-       unsigned long address;
+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;
+
        kpte_page = virt_to_page(kpte);
        BUG_ON(PageLRU(kpte_page));
        BUG_ON(PageCompound(kpte_page));
 
-       if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL)) { 
-               if (!pte_huge(*kpte)) {
-                       set_pte_atomic(kpte, mk_pte(page, prot)); 
+       if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL)) {
+               if (level == 3) {
+                       set_pte_atomic(kpte, mk_pte(page, prot));
                } else {
-                       pgprot_t ref_prot;
                        struct page *split;
+                       pgprot_t ref_prot;
 
                        ref_prot =
                        ((address & LARGE_PAGE_MASK) < (unsigned long)&_etext)
@@ -172,16 +184,19 @@ __change_page_attr(struct page *page, pgprot_t prot)
                        split = split_large_page(address, prot, ref_prot);
                        if (!split)
                                return -ENOMEM;
-                       set_pmd_pte(kpte,address,mk_pte(split, ref_prot));
+
+                       set_pmd_pte(kpte, address, mk_pte(split, ref_prot));
                        kpte_page = split;
                }
                page_private(kpte_page)++;
-       } else if (!pte_huge(*kpte)) {
-               set_pte_atomic(kpte, mk_pte(page, PAGE_KERNEL));
-               BUG_ON(page_private(kpte_page) == 0);
-               page_private(kpte_page)--;
-       } else
-               BUG();
+       } else {
+               if (level == 3) {
+                       set_pte_atomic(kpte, mk_pte(page, PAGE_KERNEL));
+                       BUG_ON(page_private(kpte_page) == 0);
+                       page_private(kpte_page)--;
+               } else
+                       BUG();
+       }
 
        /*
         * If the pte was reserved, it means it was created at boot
@@ -197,7 +212,7 @@ __change_page_attr(struct page *page, pgprot_t prot)
                }
        }
        return 0;
-} 
+}
 
 static inline void flush_map(struct list_head *l)
 {
@@ -211,32 +226,33 @@ static inline void flush_map(struct list_head *l)
  * 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.
- * 
+ *
  * The caller needs to ensure that there are no conflicting mappings elsewhere.
  * This function only deals with the kernel linear map.
- * 
+ *
  * Caller must call global_flush_tlb() after this.
  */
 int change_page_attr(struct page *page, int numpages, pgprot_t prot)
 {
-       int err = 0; 
-       int i; 
        unsigned long flags;
+       int err = 0, i;
 
        spin_lock_irqsave(&cpa_lock, flags);
-       for (i = 0; i < numpages; i++, page++) { 
+       for (i = 0; i < numpages; i++, page++) {
                err = __change_page_attr(page, prot);
-               if (err) 
-                       break; 
-       }       
+               if (err)
+                       break;
+       }
        spin_unlock_irqrestore(&cpa_lock, flags);
+
        return err;
 }
+EXPORT_SYMBOL(change_page_attr);
 
 void global_flush_tlb(void)
 {
-       struct list_head l;
        struct page *pg, *next;
+       struct list_head l;
 
        BUG_ON(irqs_disabled());
 
@@ -253,26 +269,28 @@ void global_flush_tlb(void)
                __free_page(pg);
        }
 }
+EXPORT_SYMBOL(global_flush_tlb);
 
 #ifdef CONFIG_DEBUG_PAGEALLOC
 void kernel_map_pages(struct page *page, int numpages, int enable)
 {
        if (PageHighMem(page))
                return;
-       if (!enable)
+       if (!enable) {
                debug_check_no_locks_freed(page_address(page),
                                           numpages * PAGE_SIZE);
+       }
 
-       /* the return value is ignored - the calls cannot fail,
+       /*
+        * the return value is ignored - the calls cannot fail,
         * large pages are disabled at boot time.
         */
        change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
-       /* we should perform an IPI and flush all tlbs,
+
+       /*
+        * we should perform an IPI and flush all tlbs,
         * but that can deadlock->flush only current cpu.
         */
        __flush_tlb_all();
 }
 #endif
-
-EXPORT_SYMBOL(change_page_attr);
-EXPORT_SYMBOL(global_flush_tlb);