[PATCH 07/11] x86, pageattr: Add a PTE pagetable populating function

Borislav Petkov
2013-09-19T14:54:50Z

From: Borislav Petkov <bp@suse.de>

Handle last level by unconditionally writing the PTEs into the PTE page
while paying attention to the NX bit.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
arch/x86/mm/pageattr.c | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index c56d71591617..02cf97b3bb7c 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -686,7 +686,27 @@ static int alloc_pmd_page(pud_t *pud)
return 0;
}

-#define populate_pte(cpa, start, end, pages, pmd, pgprot) do {} while (0)
+static void populate_pte(struct cpa_data *cpa,
+ unsigned long start, unsigned long end,
+ unsigned num_pages, pmd_t *pmd, pgprot_t pgprot)
+{
+ pte_t *pte;
+
+ pte = pte_offset_kernel(pmd, start);
+
+ while (num_pages-- && start < end) {
+
+ /* deal with the NX bit */
+ if (!(pgprot_val(pgprot) & _PAGE_NX))
+ cpa->pfn &= ~_PAGE_NX;
+
+ set_pte(pte, pfn_pte(cpa->pfn >> PAGE_SHIFT, pgprot));
+
+ start += PAGE_SIZE;
+ cpa->pfn += PAGE_SIZE;
+ pte++;
+ }
+}

static int populate_pmd(struct cpa_data *cpa,
unsigned long start, unsigned long end,
--
1.8.4