From 792230c3a66b3d17d6dcca712866d24f2283d4a6 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Fri, 28 Nov 2014 11:53:56 +0100 Subject: [PATCH] x86: Introduce function to get pmd entry pointer Introduces lookup_pmd_address() to get the address of the pmd entry related to a virtual address in the current address space. This function is needed for support of a virtual mapped sparse p2m list in xen pv domains, as we need the address of the pmd entry, not the one of the pte in that case. Signed-off-by: Juergen Gross Signed-off-by: David Vrabel --- arch/x86/include/asm/pgtable_types.h | 1 + arch/x86/mm/pageattr.c | 20 ++++++++++++++++++++ 2 files changed, 21 insertions(+) diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index 0778964..d83f5e7 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -396,6 +396,7 @@ static inline void update_page_count(int level, unsigned long pages) { } extern pte_t *lookup_address(unsigned long address, unsigned int *level); extern pte_t *lookup_address_in_pgd(pgd_t *pgd, unsigned long address, unsigned int *level); +extern pmd_t *lookup_pmd_address(unsigned long address); extern phys_addr_t slow_virt_to_phys(void *__address); extern int kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address, unsigned numpages, unsigned long page_flags); diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 36de293..1298108 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -384,6 +384,26 @@ static pte_t *_lookup_address_cpa(struct cpa_data *cpa, unsigned long address, } /* + * Lookup the PMD entry for a virtual address. Return a pointer to the entry + * or NULL if not present. + */ +pmd_t *lookup_pmd_address(unsigned long address) +{ + pgd_t *pgd; + pud_t *pud; + + pgd = pgd_offset_k(address); + if (pgd_none(*pgd)) + return NULL; + + pud = pud_offset(pgd, address); + if (pud_none(*pud) || pud_large(*pud) || !pud_present(*pud)) + return NULL; + + return pmd_offset(pud, address); +} + +/* * This is necessary because __pa() does not work on some * kinds of memory, like vmalloc() or the alloc_remap() * areas on 32-bit NUMA systems. The percpu areas can -- 2.7.4