Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=78c94abaea55df7003f3ad0e5b6c78ee1cc860bb
Commit:     78c94abaea55df7003f3ad0e5b6c78ee1cc860bb
Parent:     a2172e2586f6662af996e47f417bb718c37cf8d2
Author:     Ingo Molnar <[EMAIL PROTECTED]>
AuthorDate: Wed Jan 30 13:33:55 2008 +0100
Committer:  Ingo Molnar <[EMAIL PROTECTED]>
CommitDate: Wed Jan 30 13:33:55 2008 +0100

    x86: simplify the 32-bit cpa code
    
    simplify the 32-bit cpa code.
    
    Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
    Signed-off-by: Thomas Gleixner <[EMAIL PROTECTED]>
---
 arch/x86/mm/pageattr_32.c |  179 ++++++++++++++-------------------------------
 1 files changed, 56 insertions(+), 123 deletions(-)

diff --git a/arch/x86/mm/pageattr_32.c b/arch/x86/mm/pageattr_32.c
index 66688a6..570a37b 100644
--- a/arch/x86/mm/pageattr_32.c
+++ b/arch/x86/mm/pageattr_32.c
@@ -15,9 +15,6 @@
 #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, int *level)
 {
        pgd_t *pgd = pgd_offset_k(address);
@@ -48,9 +45,7 @@ split_large_page(unsigned long address, pgprot_t prot, 
pgprot_t ref_prot)
        pte_t *pbase;
        int i;
 
-       spin_unlock_irq(&cpa_lock);
        base = alloc_pages(GFP_KERNEL, 0);
-       spin_lock_irq(&cpa_lock);
        if (!base)
                return NULL;
 
@@ -58,9 +53,6 @@ split_large_page(unsigned long address, pgprot_t prot, 
pgprot_t ref_prot)
         * page_private is used to track the number of entries in
         * the page table page that have non standard attributes.
         */
-       SetPagePrivate(base);
-       page_private(base) = 0;
-
        address = __pa(address);
        addr = address & LARGE_PAGE_MASK;
        pbase = (pte_t *)page_address(base);
@@ -73,36 +65,6 @@ split_large_page(unsigned long address, pgprot_t prot, 
pgprot_t ref_prot)
        return base;
 }
 
-static void cache_flush_page(struct page *p)
-{
-       void *addr = page_address(p);
-       int i;
-
-       for (i = 0; i < PAGE_SIZE; i += boot_cpu_data.x86_clflush_size)
-               clflush(addr + i);
-}
-
-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)
-                       cache_flush_page(p);
-       } else {
-               if (boot_cpu_data.x86_model >= 4)
-                       wbinvd();
-       }
-}
-
 static void set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
 {
        unsigned long flags;
@@ -127,36 +89,12 @@ 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.
- */
-static inline void revert_page(struct page *kpte_page, unsigned long address)
-{
-       pgprot_t ref_prot;
-       pte_t *linear;
-
-       ref_prot =
-       ((address & LARGE_PAGE_MASK) < (unsigned long)&_etext)
-               ? PAGE_KERNEL_LARGE_EXEC : PAGE_KERNEL_LARGE;
-
-       linear = (pte_t *)
-               pmd_offset(pud_offset(pgd_offset_k(address), address), address);
-       set_pmd_pte(linear,  address,
-                   pfn_pte((__pa(address) & LARGE_PAGE_MASK) >> PAGE_SHIFT,
-                           ref_prot));
-}
-
-static inline void save_page(struct page *kpte_page)
-{
-       if (!test_and_set_bit(PG_arch_1, &kpte_page->flags))
-               list_add(&kpte_page->lru, &df_list);
-}
-
 static int __change_page_attr(struct page *page, pgprot_t prot)
 {
+       pgprot_t ref_prot = PAGE_KERNEL;
        struct page *kpte_page;
        unsigned long address;
+       pgprot_t oldprot;
        pte_t *kpte;
        int level;
 
@@ -167,58 +105,41 @@ static int __change_page_attr(struct page *page, pgprot_t 
prot)
        if (!kpte)
                return -EINVAL;
 
+       oldprot = pte_pgprot(*kpte);
        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 (level == 3) {
-                       set_pte_atomic(kpte, mk_pte(page, prot));
-               } else {
-                       struct page *split;
-                       pgprot_t ref_prot;
-
-                       ref_prot =
-                       ((address & LARGE_PAGE_MASK) < (unsigned long)&_etext)
-                               ? PAGE_KERNEL_EXEC : PAGE_KERNEL;
-                       split = split_large_page(address, prot, ref_prot);
-                       if (!split)
-                               return -ENOMEM;
-
-                       set_pmd_pte(kpte, address, mk_pte(split, ref_prot));
-                       kpte_page = split;
-               }
-               page_private(kpte_page)++;
-       } 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
-        * time (not via split_large_page) and in turn we must not
-        * replace it with a largepage.
+        * Better fail early if someone sets the kernel text to NX.
+        * Does not cover __inittext
         */
+       BUG_ON(address >= (unsigned long)&_text &&
+               address < (unsigned long)&_etext &&
+              (pgprot_val(prot) & _PAGE_NX));
 
-       save_page(kpte_page);
-       if (!PageReserved(kpte_page)) {
-               if (cpu_has_pse && (page_private(kpte_page) == 0)) {
-                       paravirt_release_pt(page_to_pfn(kpte_page));
-                       revert_page(kpte_page, address);
-               }
+       if ((address & LARGE_PAGE_MASK) < (unsigned long)&_etext)
+               ref_prot = PAGE_KERNEL_EXEC;
+
+       ref_prot = canon_pgprot(ref_prot);
+       prot = canon_pgprot(prot);
+
+       if (level == 3) {
+               set_pte_atomic(kpte, mk_pte(page, prot));
+       } else {
+               struct page *split;
+               split = split_large_page(address, prot, ref_prot);
+               if (!split)
+                       return -ENOMEM;
+
+               /*
+                * There's a small window here to waste a bit of RAM:
+                */
+               set_pmd_pte(kpte, address, mk_pte(split, ref_prot));
        }
        return 0;
 }
 
-static inline void flush_map(struct list_head *l)
-{
-       on_each_cpu(flush_kernel_map, l, 1, 1);
-}
-
 /*
  * Change the page attributes of an page in the linear mapping.
  *
@@ -234,40 +155,52 @@ static inline void flush_map(struct list_head *l)
  */
 int change_page_attr(struct page *page, int numpages, pgprot_t prot)
 {
-       unsigned long flags;
        int err = 0, i;
 
-       spin_lock_irqsave(&cpa_lock, flags);
        for (i = 0; i < numpages; i++, page++) {
                err = __change_page_attr(page, prot);
                if (err)
                        break;
        }
-       spin_unlock_irqrestore(&cpa_lock, flags);
 
        return err;
 }
 EXPORT_SYMBOL(change_page_attr);
 
-void global_flush_tlb(void)
+int change_page_attr_addr(unsigned long addr, int numpages, pgprot_t prot)
 {
-       struct page *pg, *next;
-       struct list_head l;
+       int i;
+       unsigned long pfn = (addr >> PAGE_SHIFT);
 
+       for (i = 0; i < numpages; i++) {
+               if (!pfn_valid(pfn + i)) {
+                       break;
+               } else {
+                       int level;
+                       pte_t *pte = lookup_address(addr + i*PAGE_SIZE, &level);
+                       BUG_ON(pte && !pte_none(*pte));
+               }
+       }
+       return change_page_attr(virt_to_page(addr), i, prot);
+}
+
+static void flush_kernel_map(void *arg)
+{
+       /*
+        * Flush all to work around Errata in early athlons regarding
+        * large page flushing.
+        */
+       __flush_tlb_all();
+
+       if (boot_cpu_data.x86_model >= 4)
+               wbinvd();
+}
+
+void global_flush_tlb(void)
+{
        BUG_ON(irqs_disabled());
 
-       spin_lock_irq(&cpa_lock);
-       list_replace_init(&df_list, &l);
-       spin_unlock_irq(&cpa_lock);
-       flush_map(&l);
-       list_for_each_entry_safe(pg, next, &l, lru) {
-               list_del(&pg->lru);
-               clear_bit(PG_arch_1, &pg->flags);
-               if (PageReserved(pg) || !cpu_has_pse || page_private(pg) != 0)
-                       continue;
-               ClearPagePrivate(pg);
-               __free_page(pg);
-       }
+       on_each_cpu(flush_kernel_map, NULL, 1, 1);
 }
 EXPORT_SYMBOL(global_flush_tlb);
 
-
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