linux/arch/sh/include/asm/pgalloc.h
Matt Fleming 5d9b4b19f1 sh: Definitions for 3-level page table layout
If using 64-bit PTEs and 4K pages then each page table has 512 entries
(as opposed to 1024 entries with 32-bit PTEs). Unlike MIPS, SH follows
the convention that all structures in the page table (pgd_t, pmd_t,
pgprot_t, etc) must be the same size. Therefore, 64-bit PTEs require
64-bit PGD entries, etc. Using 2-levels of page tables and 64-bit PTEs
it is only possible to map 1GB of virtual address space.

In order to map all 4GB of virtual address space we need to adopt a
3-level page table layout. This actually works out better for
CONFIG_SUPERH32 because we only waste 2 PGD entries on the P1 and P2
areas (which are untranslated) instead of 256.

Signed-off-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-12-17 14:31:20 +09:00

74 lines
1.6 KiB
C

#ifndef __ASM_SH_PGALLOC_H
#define __ASM_SH_PGALLOC_H
#include <linux/quicklist.h>
#include <asm/page.h>
#define QUICK_PT 1 /* Other page table pages that are zero on free */
#ifdef CONFIG_PGTABLE_LEVELS_3
#include <asm/pgalloc_pmd.h>
#else
#include <asm/pgalloc_nopmd.h>
#endif
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,
pgtable_t pte)
{
set_pmd(pmd, __pmd((unsigned long)page_address(pte)));
}
#define pmd_pgtable(pmd) pmd_page(pmd)
/*
* Allocate and free page tables.
*/
static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
unsigned long address)
{
return quicklist_alloc(QUICK_PT, GFP_KERNEL | __GFP_REPEAT, NULL);
}
static inline pgtable_t pte_alloc_one(struct mm_struct *mm,
unsigned long address)
{
struct page *page;
void *pg;
pg = quicklist_alloc(QUICK_PT, GFP_KERNEL | __GFP_REPEAT, NULL);
if (!pg)
return NULL;
page = virt_to_page(pg);
pgtable_page_ctor(page);
return page;
}
static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
{
quicklist_free(QUICK_PT, NULL, pte);
}
static inline void pte_free(struct mm_struct *mm, pgtable_t pte)
{
pgtable_page_dtor(pte);
quicklist_free_page(QUICK_PT, NULL, pte);
}
#define __pte_free_tlb(tlb,pte,addr) \
do { \
pgtable_page_dtor(pte); \
tlb_remove_page((tlb), (pte)); \
} while (0)
static inline void check_pgt_cache(void)
{
__check_pgt_cache();
quicklist_trim(QUICK_PT, NULL, 25, 16);
}
#endif /* __ASM_SH_PGALLOC_H */