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x86/mm/pageattr: Lookup address in an arbitrary PGD 

This is preparatory work in order to be able to map pages into a
specified PGD and not implicitly and only into init_mm.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
This commit is contained in:
Borislav Petkov 2013-10-31 17:25:00 +01:00 committed by Matt Fleming
parent f4fccac05f
commit 0fd64c23fd
1 changed files with 26 additions and 10 deletions
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36
arch/x86/mm/pageattr.c
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@ -30,6 +30,7 @@
*/ */
struct cpa_data { struct cpa_data {
unsigned long *vaddr; unsigned long *vaddr;
pgd_t *pgd;
pgprot_t mask_set; pgprot_t mask_set;
pgprot_t mask_clr; pgprot_t mask_clr;
int numpages; int numpages;
@ -322,17 +323,9 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
return prot; return prot;
} }
/* static pte_t *__lookup_address_in_pgd(pgd_t *pgd, unsigned long address,
* Lookup the page table entry for a virtual address. Return a pointer unsigned int *level)
* to the entry and the level of the mapping.
*
* Note: We return pud and pmd either when the entry is marked large
* or when the present bit is not set. Otherwise we would return a
* pointer to a nonexisting mapping.
*/
pte_t *lookup_address(unsigned long address, unsigned int *level)
{ {
pgd_t *pgd = pgd_offset_k(address);
pud_t *pud; pud_t *pud;
pmd_t *pmd; pmd_t *pmd;
@ -361,8 +354,31 @@ pte_t *lookup_address(unsigned long address, unsigned int *level)
return pte_offset_kernel(pmd, address); return pte_offset_kernel(pmd, address);
} }
/*
* Lookup the page table entry for a virtual address. Return a pointer
* to the entry and the level of the mapping.
*
* Note: We return pud and pmd either when the entry is marked large
* or when the present bit is not set. Otherwise we would return a
* pointer to a nonexisting mapping.
*/
pte_t *lookup_address(unsigned long address, unsigned int *level)
{
return __lookup_address_in_pgd(pgd_offset_k(address), address, level);
}
EXPORT_SYMBOL_GPL(lookup_address); EXPORT_SYMBOL_GPL(lookup_address);
static pte_t *_lookup_address_cpa(struct cpa_data *cpa, unsigned long address,
unsigned int *level)
{
if (cpa->pgd)
return __lookup_address_in_pgd(cpa->pgd + pgd_index(address),
address, level);
return lookup_address(address, level);
}
/* /*
* This is necessary because __pa() does not work on some * This is necessary because __pa() does not work on some
* kinds of memory, like vmalloc() or the alloc_remap() * kinds of memory, like vmalloc() or the alloc_remap()