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-rw-r--r--arch/x86/xen/mmu.c37
1 files changed, 37 insertions, 0 deletions
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 5e41f7fc6cf..d2e8ed1aff3 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1396,6 +1396,43 @@ static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
#endif
}
+#ifdef CONFIG_HIGHPTE
+static void *xen_kmap_atomic_pte(struct page *page, enum km_type type)
+{
+ pgprot_t prot = PAGE_KERNEL;
+
+ if (PagePinned(page))
+ prot = PAGE_KERNEL_RO;
+
+ if (0 && PageHighMem(page))
+ printk("mapping highpte %lx type %d prot %s\n",
+ page_to_pfn(page), type,
+ (unsigned long)pgprot_val(prot) & _PAGE_RW ? "WRITE" : "READ");
+
+ return kmap_atomic_prot(page, type, prot);
+}
+#endif
+
+#ifdef CONFIG_X86_32
+static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte)
+{
+ /* If there's an existing pte, then don't allow _PAGE_RW to be set */
+ if (pte_val_ma(*ptep) & _PAGE_PRESENT)
+ pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
+ pte_val_ma(pte));
+
+ return pte;
+}
+
+/* Init-time set_pte while constructing initial pagetables, which
+ doesn't allow RO pagetable pages to be remapped RW */
+static __init void xen_set_pte_init(pte_t *ptep, pte_t pte)
+{
+ pte = mask_rw_pte(ptep, pte);
+
+ xen_set_pte(ptep, pte);
+}
+#endif
/* Early in boot, while setting up the initial pagetable, assume
everything is pinned. */