[PATCH 03/11] x86, pageattr: Lookup address in an arbitrary PGD

Borislav Petkov
2013-09-19T14:55:10Z

From: Borislav Petkov <bp@suse.de>

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>
---
arch/x86/mm/pageattr.c | 36 ++++++++++++++++++++++++++----------
1 file changed, 26 insertions(+), 10 deletions(-)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index bb32480c2d71..c53de62a1170 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -30,6 +30,7 @@
*/
struct cpa_data {
unsigned long *vaddr;
+ pgd_t *pgd;
pgprot_t mask_set;
pgprot_t mask_clr;
int numpages;
@@ -322,17 +323,9 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
return prot;
}

-/*
- * 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)
+static pte_t *__lookup_address_in_pgd(pgd_t *pgd, unsigned long address,
+ unsigned int *level)
{
- pgd_t *pgd = pgd_offset_k(address);
pud_t *pud;
pmd_t *pmd;

@@ -361,8 +354,31 @@ pte_t *lookup_address(unsigned long address, unsigned int *level)

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);

+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
* kinds of memory, like vmalloc() or the alloc_remap()
--
1.8.4