linux/x86-64: initialization code cleanup

Index: head-2008-05-08/arch/x86_64/mm/init-xen.c
===================================================================
@@ -60,6 +60,8 @@ unsigned int __kernel_page_user;
 EXPORT_SYMBOL(__kernel_page_user);
 #endif
 
+int after_bootmem;
+
 extern unsigned long *contiguous_bitmap;
 
 static unsigned long dma_reserve __initdata;

@@ -99,6 +101,8 @@ void __meminit early_make_page_readonly(
 	pte_t pte, *ptep;
 	unsigned long *page = (unsigned long *) init_level4_pgt;
 
+	BUG_ON(after_bootmem);
+
 	if (xen_feature(feature))
 		return;
 

@@ -236,7 +240,6 @@ void show_mem(void)
 	printk(KERN_INFO "%lu pages swap cached\n",cached);
 }
 
-int after_bootmem;
 
 static __init void *spp_getpage(void)
 { 

@@ -440,11 +443,6 @@ static __meminit void *alloc_static_page
 
 #define PTE_SIZE PAGE_SIZE
 
-static inline void __set_pte(pte_t *dst, pte_t val)
-{
-	*dst = val;
-}
-
 static inline int make_readonly(unsigned long paddr)
 {
 	extern char __vsyscall_0;

@@ -539,12 +537,8 @@ phys_pmd_init(pmd_t *pmd_page, unsigned 
 		unsigned long pte_phys;
 		pte_t *pte, *pte_save;
 
-		if (address >= end) {
-			if (!after_bootmem)
-				for (; i < PTRS_PER_PMD; i++, pmd++)
-					set_pmd(pmd, __pmd(0));
+		if (address >= end)
 			break;
-		}
 		pte = alloc_static_page(&pte_phys);
 		pte_save = pte;
 		for (k = 0; k < PTRS_PER_PTE; pte++, k++, address += PTE_SIZE) {

@@ -557,17 +550,21 @@ phys_pmd_init(pmd_t *pmd_page, unsigned 
 		for (k = 0; k < PTRS_PER_PTE; pte++, k++, address += PTE_SIZE) {
 			unsigned long pteval = address | _PAGE_NX | _KERNPG_TABLE;
 
-			if ((address >= end) ||
-			    ((address >> PAGE_SHIFT) >=
-			     xen_start_info->nr_pages))
+			if (address >= (after_bootmem
+			                ? end
+			                : xen_start_info->nr_pages << PAGE_SHIFT))
 				pteval = 0;
 			else if (make_readonly(address))
 				pteval &= ~_PAGE_RW;
-			__set_pte(pte, __pte(pteval & __supported_pte_mask));
+			set_pte(pte, __pte(pteval & __supported_pte_mask));
+		}
+		if (!after_bootmem) {
+			early_make_page_readonly(pte_save, XENFEAT_writable_page_tables);
+			*pmd = __pmd(pte_phys | _KERNPG_TABLE);
+		} else {
+			make_page_readonly(pte_save, XENFEAT_writable_page_tables);
+			set_pmd(pmd, __pmd(pte_phys | _KERNPG_TABLE));
 		}
-		pte = pte_save;
-		early_make_page_readonly(pte, XENFEAT_writable_page_tables);
-		set_pmd(pmd, __pmd(pte_phys | _KERNPG_TABLE));
 	}
 }
 

@@ -600,11 +597,13 @@ phys_pud_init(pud_t *pud_page, unsigned 
 			break;
 
 		pmd = alloc_static_page(&pmd_phys);
-		early_make_page_readonly(pmd, XENFEAT_writable_page_tables);
+
 		spin_lock(&init_mm.page_table_lock);
-		set_pud(pud, __pud(pmd_phys | _KERNPG_TABLE));
+		*pud = __pud(pmd_phys | _KERNPG_TABLE);
 		phys_pmd_init(pmd, paddr, end);
 		spin_unlock(&init_mm.page_table_lock);
+
+		early_make_page_readonly(pmd, XENFEAT_writable_page_tables);
 	}
 	__flush_tlb();
 } 

@@ -857,20 +855,18 @@ void init_memory_mapping(unsigned long
 		pgd_t *pgd = pgd_offset_k(start);
 		pud_t *pud;
 
-		if (after_bootmem) {
+		if (after_bootmem)
 			pud = pud_offset(pgd, start & PGDIR_MASK);
-			make_page_readonly(pud, XENFEAT_writable_page_tables);
-			pud_phys = __pa(pud);
-		} else {
+		else
 			pud = alloc_static_page(&pud_phys);
-			early_make_page_readonly(pud, XENFEAT_writable_page_tables);
-		}
 		next = start + PGDIR_SIZE;
 		if (next > end) 
 			next = end; 
 		phys_pud_init(pud, __pa(start), __pa(next));
-		if (!after_bootmem)
+		if (!after_bootmem) {
+			early_make_page_readonly(pud, XENFEAT_writable_page_tables);
 			set_pgd(pgd_offset_k(start), mk_kernel_pgd(pud_phys));
+		}
 	}
 
 	if (!after_bootmem) {