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authorDave Hansen <dave@linux.vnet.ibm.com>2013-01-22 13:24:31 -0800
committerH. Peter Anvin <hpa@linux.intel.com>2013-01-25 16:33:22 -0800
commit4cbeb51b860c57ba8b2ae50c4016ee7a41f5fbd5 (patch)
treebf51acd1c4e8c21b15e06fd87c646018efe5e0b2 /arch/x86/include/asm/pgtable.h
parenta25b9316841c5afa226f8f70a457861b35276a92 (diff)
downloadop-kernel-dev-4cbeb51b860c57ba8b2ae50c4016ee7a41f5fbd5.zip
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x86, mm: Pagetable level size/shift/mask helpers
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>
Diffstat (limited to 'arch/x86/include/asm/pgtable.h')
-rw-r--r--arch/x86/include/asm/pgtable.h14
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 5199db2..bc28e6f 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -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__ */
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