Messages in this thread Patch in this message | | | Subject | [PATCH 2/5] pagetable level size/shift/mask helpers | From | Dave Hansen <> | Date | Tue, 22 Jan 2013 13:24:31 -0800 |
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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> ---
linux-2.6.git-dave/arch/x86/include/asm/pgtable.h | 14 ++++++++++++++ linux-2.6.git-dave/arch/x86/include/asm/pgtable_types.h | 2 +- 2 files changed, 15 insertions(+), 1 deletion(-)
diff -puN arch/x86/include/asm/pgtable.h~pagetable-level-size-helpers arch/x86/include/asm/pgtable.h --- linux-2.6.git/arch/x86/include/asm/pgtable.h~pagetable-level-size-helpers 2013-01-22 13:17:15.464309478 -0800 +++ linux-2.6.git-dave/arch/x86/include/asm/pgtable.h 2013-01-22 13:17:15.472309544 -0800 @@ -390,6 +390,7 @@ pte_t *populate_extra_pte(unsigned long #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 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__ */ diff -puN arch/x86/include/asm/pgtable_types.h~pagetable-level-size-helpers arch/x86/include/asm/pgtable_types.h --- linux-2.6.git/arch/x86/include/asm/pgtable_types.h~pagetable-level-size-helpers 2013-01-22 13:17:15.468309511 -0800 +++ linux-2.6.git-dave/arch/x86/include/asm/pgtable_types.h 2013-01-22 13:17:15.472309544 -0800 @@ -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, _
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