ARM: pgtable: switch order of Linux vs hardware page tables
This switches the ordering of the Linux vs hardware page tables in
each page, thereby eliminating some of the arithmetic in the page
table walks. As we now place the Linux page table at the beginning
of the page, we can deal with the offset in the pgt by simply masking
it away, along with the other control bits.
This also makes the arithmetic all be positive, rather than a mixture.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/include/asm/pgalloc.h b/arch/arm/include/asm/pgalloc.h
index 1f1064b..9763be0 100644
--- a/arch/arm/include/asm/pgalloc.h
+++ b/arch/arm/include/asm/pgalloc.h
@@ -35,6 +35,11 @@
#define PGALLOC_GFP (GFP_KERNEL | __GFP_NOTRACK | __GFP_REPEAT | __GFP_ZERO)
+static inline void clean_pte_table(pte_t *pte)
+{
+ clean_dcache_area(pte + PTE_HWTABLE_PTRS, PTE_HWTABLE_SIZE);
+}
+
/*
* Allocate one PTE table.
*
@@ -42,14 +47,14 @@
* into one table thus:
*
* +------------+
- * | h/w pt 0 |
- * +------------+
- * | h/w pt 1 |
- * +------------+
* | Linux pt 0 |
* +------------+
* | Linux pt 1 |
* +------------+
+ * | h/w pt 0 |
+ * +------------+
+ * | h/w pt 1 |
+ * +------------+
*/
static inline pte_t *
pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr)
@@ -57,10 +62,8 @@
pte_t *pte;
pte = (pte_t *)__get_free_page(PGALLOC_GFP);
- if (pte) {
- clean_dcache_area(pte, sizeof(pte_t) * PTRS_PER_PTE);
- pte += PTRS_PER_PTE;
- }
+ if (pte)
+ clean_pte_table(pte);
return pte;
}
@@ -76,10 +79,8 @@
pte = alloc_pages(PGALLOC_GFP, 0);
#endif
if (pte) {
- if (!PageHighMem(pte)) {
- void *page = page_address(pte);
- clean_dcache_area(page, sizeof(pte_t) * PTRS_PER_PTE);
- }
+ if (!PageHighMem(pte))
+ clean_pte_table(page_address(pte));
pgtable_page_ctor(pte);
}
@@ -91,10 +92,8 @@
*/
static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
{
- if (pte) {
- pte -= PTRS_PER_PTE;
+ if (pte)
free_page((unsigned long)pte);
- }
}
static inline void pte_free(struct mm_struct *mm, pgtable_t pte)
@@ -106,7 +105,7 @@
static inline void __pmd_populate(pmd_t *pmdp, phys_addr_t pte,
unsigned long prot)
{
- unsigned long pmdval = pte | prot;
+ unsigned long pmdval = (pte + PTE_HWTABLE_OFF) | prot;
pmdp[0] = __pmd(pmdval);
pmdp[1] = __pmd(pmdval + 256 * sizeof(pte_t));
flush_pmd_entry(pmdp);
@@ -121,14 +120,10 @@
static inline void
pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp, pte_t *ptep)
{
- unsigned long pte_ptr = (unsigned long)ptep;
-
/*
- * The pmd must be loaded with the physical
- * address of the PTE table
+ * The pmd must be loaded with the physical address of the PTE table
*/
- pte_ptr -= PTRS_PER_PTE * sizeof(void *);
- __pmd_populate(pmdp, __pa(pte_ptr), _PAGE_KERNEL_TABLE);
+ __pmd_populate(pmdp, __pa(ptep), _PAGE_KERNEL_TABLE);
}
static inline void