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Subject[PATCH 1 of 4] x86: unify PAE/non-PAE pgd_ctor
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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>

---
arch/x86/mm/pgtable_32.c | 58 +++++++++++++++++-----------------------------
1 file changed, 22 insertions(+), 36 deletions(-)

diff --git a/arch/x86/mm/pgtable_32.c b/arch/x86/mm/pgtable_32.c
--- a/arch/x86/mm/pgtable_32.c
+++ b/arch/x86/mm/pgtable_32.c
@@ -219,50 +219,39 @@
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,
+ /* 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);
- pgd_list_add(pgd);
+ paravirt_alloc_pd_clone(__pa(pgd) >> PAGE_SHIFT,
+ __pa(swapper_pg_dir) >> PAGE_SHIFT,
+ USER_PTRS_PER_PGD,
+ KERNEL_PGD_PTRS);
+ }
+
+ /* list required to sync kernel mapping updates */
+ if (!SHARED_KERNEL_PMD)
+ 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,
- swapper_pg_dir + USER_PTRS_PER_PGD,
- KERNEL_PGD_PTRS);
- } else {
- unsigned long flags;
-
- memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
- spin_lock_irqsave(&pgd_lock, flags);
- pgd_list_add(pgd);
- spin_unlock_irqrestore(&pgd_lock, flags);
- }
-}
-#endif /* PTRS_PER_PMD */

static void pgd_dtor(void *pgd)
{
@@ -275,9 +264,6 @@
pgd_list_del(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
/*



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