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 <[email protected]> Signed-off-by: Dave Hansen <[email protected]> --- 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 2013-01-17 10:22:25.958428542 -0800 +++ linux-2.6.git-dave/arch/x86/include/asm/pgtable.h 2013-01-17 10:22:25.962428578 -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 2013-01-17 10:22:25.958428542 -0800 +++ linux-2.6.git-dave/arch/x86/include/asm/pgtable_types.h 2013-01-17 10:22:25.966428612 -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, _ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
