x86/mm/ident_map: Use gbpages only where full GB page should be mapped.

[linux-2.6-microblaze.git] / arch / x86 / mm / ident_map.c

diff --git a/arch/x86/mm/ident_map.c b/arch/x86/mm/ident_map.c
index 968d700..f50cc21 100644 (file)
--- a/arch/x86/mm/ident_map.c
+++ b/arch/x86/mm/ident_map.c
@@ -26,18 +26,31 @@ static int ident_pud_init(struct x86_mapping_info *info, pud_t *pud_page,
        for (; addr < end; addr = next) {
                pud_t *pud = pud_page + pud_index(addr);
                pmd_t *pmd;
+               bool use_gbpage;
 
                next = (addr & PUD_MASK) + PUD_SIZE;
                if (next > end)
                        next = end;
 
-               if (info->direct_gbpages) {
-                       pud_t pudval;
+               /* if this is already a gbpage, this portion is already mapped */
+               if (pud_large(*pud))
+                       continue;
+
+               /* Is using a gbpage allowed? */
+               use_gbpage = info->direct_gbpages;
 
-                       if (pud_present(*pud))
-                               continue;
+               /* Don't use gbpage if it maps more than the requested region. */
+               /* at the begining: */
+               use_gbpage &= ((addr & ~PUD_MASK) == 0);
+               /* ... or at the end: */
+               use_gbpage &= ((next & ~PUD_MASK) == 0);
+
+               /* Never overwrite existing mappings */
+               use_gbpage &= !pud_present(*pud);
+
+               if (use_gbpage) {
+                       pud_t pudval;
 
-                       addr &= PUD_MASK;
                        pudval = __pud((addr - info->offset) | info->page_flag);
                        set_pud(pud, pudval);
                        continue;