avr32: Store virtual addresses in the PGD

Instead of storing physical addresses along with page flags in the
PGD, store virtual addresses and use NULL to indicate a not present
second-level page table. A non-page-aligned page table indicates a bad
PMD.

This simplifies the TLB miss handler since it no longer has to check
the Present bit and no longer has to convert the PGD entry from
physical to virtual address. Instead, it has to check for a NULL
entry, which is slightly cheaper than either.

Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>

2 files changed, 24 insertions, 28 deletions

diff --git a/include/asm-avr32/pgalloc.h b/include/asm-avr32/pgalloc.h
index 51fc1f6e4b1..5b768fc2388 100644
--- a/include/asm-avr32/pgalloc.h
+++ b/include/asm-avr32/pgalloc.h
@@ -8,25 +8,27 @@
 #ifndef __ASM_AVR32_PGALLOC_H
 #define __ASM_AVR32_PGALLOC_H
 
-#include <asm/processor.h>
-#include <linux/threads.h>
-#include <linux/slab.h>
 #include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
 
-#define pmd_populate_kernel(mm, pmd, pte) \
-	set_pmd(pmd, __pmd(_PAGE_TABLE + __pa(pte)))
+static inline void pmd_populate_kernel(struct mm_struct *mm,
+				       pmd_t *pmd, pte_t *pte)
+{
+	set_pmd(pmd, __pmd((unsigned long)pte));
+}
 
-static __inline__ void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
+static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
 				    pgtable_t pte)
 {
-	set_pmd(pmd, __pmd(_PAGE_TABLE + page_to_phys(pte)));
+	set_pmd(pmd, __pmd((unsigned long)page_address(pte)));
 }
 #define pmd_pgtable(pmd) pmd_page(pmd)
 
 /*
  * Allocate and free page tables
  */
-static __inline__ pgd_t *pgd_alloc(struct mm_struct *mm)
+static inline pgd_t *pgd_alloc(struct mm_struct *mm)
 {
 	return kcalloc(USER_PTRS_PER_PGD, sizeof(pgd_t), GFP_KERNEL);
 }
diff --git a/include/asm-avr32/pgtable.h b/include/asm-avr32/pgtable.h
index c0e5e29417d..fecdda16f44 100644
--- a/include/asm-avr32/pgtable.h
+++ b/include/asm-avr32/pgtable.h
@@ -129,13 +129,6 @@ extern struct page *empty_zero_page;
 
 #define _PAGE_FLAGS_CACHE_MASK	(_PAGE_CACHABLE | _PAGE_BUFFER | _PAGE_WT)
 
-/* TODO: Check for saneness */
-/* User-mode page table flags (to be set in a pgd or pmd entry) */
-#define _PAGE_TABLE		(_PAGE_PRESENT | _PAGE_TYPE_SMALL | _PAGE_RW \
-				 | _PAGE_USER | _PAGE_ACCESSED | _PAGE_DIRTY)
-/* Kernel-mode page table flags */
-#define _KERNPG_TABLE		(_PAGE_PRESENT | _PAGE_TYPE_SMALL | _PAGE_RW \
-				 | _PAGE_ACCESSED | _PAGE_DIRTY)
 /* Flags that may be modified by software */
 #define _PAGE_CHG_MASK		(PTE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY \
 				 | _PAGE_FLAGS_CACHE_MASK)
@@ -262,10 +255,14 @@ static inline pte_t pte_mkspecial(pte_t pte)
 }
 
 #define pmd_none(x)	(!pmd_val(x))
-#define pmd_present(x)	(pmd_val(x) & _PAGE_PRESENT)
-#define pmd_clear(xp)	do { set_pmd(xp, __pmd(0)); } while (0)
-#define	pmd_bad(x)	((pmd_val(x) & (~PAGE_MASK & ~_PAGE_USER))	\
-			 != _KERNPG_TABLE)
+#define pmd_present(x)	(pmd_val(x))
+
+static inline void pmd_clear(pmd_t *pmdp)
+{
+	set_pmd(pmdp, __pmd(0));
+}
+
+#define	pmd_bad(x)	(pmd_val(x) & ~PAGE_MASK)
 
 /*
  * Permanent address of a page. We don't support highmem, so this is
@@ -303,19 +300,16 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 
 #define page_pte(page)	page_pte_prot(page, __pgprot(0))
 
-#define pmd_page_vaddr(pmd)					\
-	((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
-
-#define pmd_page(pmd)	(phys_to_page(pmd_val(pmd)))
+#define pmd_page_vaddr(pmd)	pmd_val(pmd)
+#define pmd_page(pmd)		(virt_to_page(pmd_val(pmd)))
 
 /* to find an entry in a page-table-directory. */
-#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
-#define pgd_offset(mm, address) ((mm)->pgd+pgd_index(address))
-#define pgd_offset_current(address)				\
-	((pgd_t *)__mfsr(SYSREG_PTBR) + pgd_index(address))
+#define pgd_index(address)	(((address) >> PGDIR_SHIFT)	\
+				 & (PTRS_PER_PGD - 1))
+#define pgd_offset(mm, address)	((mm)->pgd + pgd_index(address))
 
 /* to find an entry in a kernel page-table-directory */
-#define pgd_offset_k(address) pgd_offset(&init_mm, address)
+#define pgd_offset_k(address)	pgd_offset(&init_mm, address)
 
 /* Find an entry in the third-level page table.. */
 #define pte_index(address)				\