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x86, mm: Pagetable level size/shift/mask helpers

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I plan to use lookup_address() to walk the kernel pagetables
in a later patch.  It returns a "pte" and the level in the
pagetables where the "pte" was found.  The level is just an
enum and needs to be converted to a useful value in order to
do address calculations with it.  These helpers will be used
in at least two places.

This also gives the anonymous enum a real name so that no one
gets confused about what they should be passing in to these
helpers.

"PTE_SHIFT" was chosen for naming consistency with the other
pagetable levels (PGD/PUD/PMD_SHIFT).

Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20130122212431.405D3A8C@kernel.stglabs.ibm.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Dave Hansen 2013-01-22 13:24:31 -08:00 • committed by H. Peter Anvin
commit 4cbeb51b86
2 changed files with 15 additions and 1 deletions
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14
arch/x86/include/asm/pgtable.h
View file

@ -390,6 +390,7 @@ pte_t *populate_extra_pte(unsigned long vaddr);
#ifndef __ASSEMBLY__
#include <linux/mm_types.h>
#include <linux/log2.h>
static inline int pte_none(pte_t pte)
{
@ -781,6 +782,19 @@ static inline void clone_pgd_range(pgd_t *dst, pgd_t *src, int count)
memcpy(dst, src, count * sizeof(pgd_t));
}
#define PTE_SHIFT ilog2(PTRS_PER_PTE)
static inline int page_level_shift(enum pg_level level)
{
return (PAGE_SHIFT - PTE_SHIFT) + level * PTE_SHIFT;
}
static inline unsigned long page_level_size(enum pg_level level)
{
return 1UL << page_level_shift(level);
}
static inline unsigned long page_level_mask(enum pg_level level)
{
return ~(page_level_size(level) - 1);
}
#include <asm-generic/pgtable.h>
#endif /* __ASSEMBLY__ */

2
arch/x86/include/asm/pgtable_types.h
View file

@ -331,7 +331,7 @@ extern void native_pagetable_init(void);
struct seq_file;
extern void arch_report_meminfo(struct seq_file *m);
enum {
enum pg_level {
PG_LEVEL_NONE,
PG_LEVEL_4K,
PG_LEVEL_2M,