x86: unify PAE/non-PAE pgd_ctor

The constructors for PAE and non-PAE pgd_ctors are more or less
identical, and can be made into the same function.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: William Irwin <wli@holomorphy.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 20 insertions, 34 deletions

diff --git a/arch/x86/mm/pgtable_32.c b/arch/x86/mm/pgtable_32.c
index cb3aa470249..f34e33d1844 100644
--- a/arch/x86/mm/pgtable_32.c
+++ b/arch/x86/mm/pgtable_32.c
@@ -219,50 +219,39 @@ static inline void pgd_list_del(pgd_t *pgd)
         list_del(&page->lru);
 }
 
+#define UNSHARED_PTRS_PER_PGD                           \
+        (SHARED_KERNEL_PMD ? USER_PTRS_PER_PGD : PTRS_PER_PGD)
 
-
-#if (PTRS_PER_PMD == 1)
-/* Non-PAE pgd constructor */
-static void pgd_ctor(void *pgd)
+static void pgd_ctor(void *p)
 {
+        pgd_t *pgd = p;
         unsigned long flags;
 
-        /* !PAE, no pagetable sharing */
+        /* Clear usermode parts of PGD */
         memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
 
         spin_lock_irqsave(&pgd_lock, flags);
 
-        /* must happen under lock */
-        clone_pgd_range((pgd_t *)pgd + USER_PTRS_PER_PGD,
-                        swapper_pg_dir + USER_PTRS_PER_PGD,
-                        KERNEL_PGD_PTRS);
-        paravirt_alloc_pd_clone(__pa(pgd) >> PAGE_SHIFT,
-                                __pa(swapper_pg_dir) >> PAGE_SHIFT,
-                                USER_PTRS_PER_PGD,
-                                KERNEL_PGD_PTRS);
-        pgd_list_add(pgd);
-        spin_unlock_irqrestore(&pgd_lock, flags);
-}
-#else  /* PTRS_PER_PMD > 1 */
-/* PAE pgd constructor */
-static void pgd_ctor(void *pgd)
-{
-        /* PAE, kernel PMD may be shared */
-
-        if (SHARED_KERNEL_PMD) {
-                clone_pgd_range((pgd_t *)pgd + USER_PTRS_PER_PGD,
+        /* If the pgd points to a shared pagetable level (either the
+           ptes in non-PAE, or shared PMD in PAE), then just copy the
+           references from swapper_pg_dir. */
+        if (PAGETABLE_LEVELS == 2 ||
+            (PAGETABLE_LEVELS == 3 && SHARED_KERNEL_PMD)) {
+                clone_pgd_range(pgd + USER_PTRS_PER_PGD,
                                 swapper_pg_dir + USER_PTRS_PER_PGD,
                                 KERNEL_PGD_PTRS);
-        } else {
-                unsigned long flags;
+                paravirt_alloc_pd_clone(__pa(pgd) >> PAGE_SHIFT,
+                                        __pa(swapper_pg_dir) >> PAGE_SHIFT,
+                                        USER_PTRS_PER_PGD,
+                                        KERNEL_PGD_PTRS);
+        }
 
-                memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
-                spin_lock_irqsave(&pgd_lock, flags);
+        /* list required to sync kernel mapping updates */
+        if (!SHARED_KERNEL_PMD)
                 pgd_list_add(pgd);
-                spin_unlock_irqrestore(&pgd_lock, flags);
-        }
+
+        spin_unlock_irqrestore(&pgd_lock, flags);
 }
-#endif  /* PTRS_PER_PMD */
 
 static void pgd_dtor(void *pgd)
 {
@@ -276,9 +265,6 @@ static void pgd_dtor(void *pgd)
         spin_unlock_irqrestore(&pgd_lock, flags);
 }
 
-#define UNSHARED_PTRS_PER_PGD                           \
-        (SHARED_KERNEL_PMD ? USER_PTRS_PER_PGD : PTRS_PER_PGD)
-
 #ifdef CONFIG_X86_PAE
 /*
  * Mop up any pmd pages which may still be attached to the pgd.