Merge branch 'stable/bug-fixes-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

* 'stable/bug-fixes-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen: mask_rw_pte: do not apply the early_ioremap checks on x86_32
  xen: do not create the extra e820 region at an addr lower than 4G

arch/x86/xen/mmu.c

@@ -1473,16 +1473,20 @@ static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
 #endif
 }
 
+#ifdef CONFIG_X86_32
 static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte)
 {
-	unsigned long pfn = pte_pfn(pte);
-
-#ifdef CONFIG_X86_32
 	/* 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));
-#endif
+
+	return pte;
+}
+#else /* CONFIG_X86_64 */
+static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte)
+{
+	unsigned long pfn = pte_pfn(pte);
 
 	/*
 	 * If the new pfn is within the range of the newly allocated
@@ -1497,6 +1501,7 @@ static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte)
 
 	return pte;
 }
+#endif /* CONFIG_X86_64 */
 
 /* Init-time set_pte while constructing initial pagetables, which
    doesn't allow RO pagetable pages to be remapped RW */

arch/x86/xen/setup.c

@@ -227,7 +227,7 @@ char * __init xen_memory_setup(void)
 
 	memcpy(map_raw, map, sizeof(map));
 	e820.nr_map = 0;
-	xen_extra_mem_start = mem_end;
+	xen_extra_mem_start = max((1ULL << 32), mem_end);
 	for (i = 0; i < memmap.nr_entries; i++) {
 		unsigned long long end;