Merge branch 'for-linus' of git://one.firstfloor.org/home/andi/git/linux-2.6

* 'for-linus' of git://one.firstfloor.org/home/andi/git/linux-2.6: (231 commits)
  [PATCH] i386: Don't delete cpu_devs data to identify different x86 types in late_initcall
  [PATCH] i386: type may be unused
  [PATCH] i386: Some additional chipset register values validation.
  [PATCH] i386: Add missing !X86_PAE dependincy to the 2G/2G split.
  [PATCH] x86-64: Don't exclude asm-offsets.c in Documentation/dontdiff
  [PATCH] i386: avoid redundant preempt_disable in __unlazy_fpu
  [PATCH] i386: white space fixes in i387.h
  [PATCH] i386: Drop noisy e820 debugging printks
  [PATCH] x86-64: Fix allnoconfig error in genapic_flat.c
  [PATCH] x86-64: Shut up warnings for vfat compat ioctls on other file systems
  [PATCH] x86-64: Share identical video.S between i386 and x86-64
  [PATCH] x86-64: Remove CONFIG_REORDER
  [PATCH] x86-64: Print type and size correctly for unknown compat ioctls
  [PATCH] i386: Remove copy_*_user BUG_ONs for (size < 0)
  [PATCH] i386: Little cleanups in smpboot.c
  [PATCH] x86-64: Don't enable NUMA for a single node in K8 NUMA scanning
  [PATCH] x86: Use RDTSCP for synchronous get_cycles if possible
  [PATCH] i386: Add X86_FEATURE_RDTSCP
  [PATCH] i386: Implement X86_FEATURE_SYNC_RDTSC on i386
  [PATCH] i386: Implement alternative_io for i386
  ...

Fix up trivial conflict in include/linux/highmem.h manually.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

5 files changed, 252 insertions, 114 deletions

diff --git a/arch/i386/mm/fault.c b/arch/i386/mm/fault.c
index b8c4e259fc8..f534c29e80b 100644
--- a/arch/i386/mm/fault.c
+++ b/arch/i386/mm/fault.c
@@ -20,6 +20,7 @@
 #include <linux/tty.h>
 #include <linux/vt_kern.h>		/* For unblank_screen() */
 #include <linux/highmem.h>
+#include <linux/bootmem.h>		/* for max_low_pfn */
 #include <linux/module.h>
 #include <linux/kprobes.h>
 #include <linux/uaccess.h>
@@ -301,7 +302,6 @@ fastcall void __kprobes do_page_fault(struct pt_regs *regs,
 	struct mm_struct *mm;
 	struct vm_area_struct * vma;
 	unsigned long address;
-	unsigned long page;
 	int write, si_code;
 
 	/* get the address */
@@ -510,7 +510,9 @@ no_context:
 	bust_spinlocks(1);
 
 	if (oops_may_print()) {
-	#ifdef CONFIG_X86_PAE
+		__typeof__(pte_val(__pte(0))) page;
+
+#ifdef CONFIG_X86_PAE
 		if (error_code & 16) {
 			pte_t *pte = lookup_address(address);
 
@@ -519,7 +521,7 @@ no_context:
 					"NX-protected page - exploit attempt? "
 					"(uid: %d)\n", current->uid);
 		}
-	#endif
+#endif
 		if (address < PAGE_SIZE)
 			printk(KERN_ALERT "BUG: unable to handle kernel NULL "
 					"pointer dereference");
@@ -529,25 +531,38 @@ no_context:
 		printk(" at virtual address %08lx\n",address);
 		printk(KERN_ALERT " printing eip:\n");
 		printk("%08lx\n", regs->eip);
-	}
-	page = read_cr3();
-	page = ((unsigned long *) __va(page))[address >> 22];
-	if (oops_may_print())
+
+		page = read_cr3();
+		page = ((__typeof__(page) *) __va(page))[address >> PGDIR_SHIFT];
+#ifdef CONFIG_X86_PAE
+		printk(KERN_ALERT "*pdpt = %016Lx\n", page);
+		if ((page >> PAGE_SHIFT) < max_low_pfn
+		    && page & _PAGE_PRESENT) {
+			page &= PAGE_MASK;
+			page = ((__typeof__(page) *) __va(page))[(address >> PMD_SHIFT)
+			                                         & (PTRS_PER_PMD - 1)];
+			printk(KERN_ALERT "*pde = %016Lx\n", page);
+			page &= ~_PAGE_NX;
+		}
+#else
 		printk(KERN_ALERT "*pde = %08lx\n", page);
-	/*
-	 * We must not directly access the pte in the highpte
-	 * case, the page table might be allocated in highmem.
-	 * And lets rather not kmap-atomic the pte, just in case
-	 * it's allocated already.
-	 */
-#ifndef CONFIG_HIGHPTE
-	if ((page & 1) && oops_may_print()) {
-		page &= PAGE_MASK;
-		address &= 0x003ff000;
-		page = ((unsigned long *) __va(page))[address >> PAGE_SHIFT];
-		printk(KERN_ALERT "*pte = %08lx\n", page);
-	}
 #endif
+
+		/*
+		 * We must not directly access the pte in the highpte
+		 * case if the page table is located in highmem.
+		 * And let's rather not kmap-atomic the pte, just in case
+		 * it's allocated already.
+		 */
+		if ((page >> PAGE_SHIFT) < max_low_pfn
+		    && (page & _PAGE_PRESENT)) {
+			page &= PAGE_MASK;
+			page = ((__typeof__(page) *) __va(page))[(address >> PAGE_SHIFT)
+			                                         & (PTRS_PER_PTE - 1)];
+			printk(KERN_ALERT "*pte = %0*Lx\n", sizeof(page)*2, (u64)page);
+		}
+	}
+
 	tsk->thread.cr2 = address;
 	tsk->thread.trap_no = 14;
 	tsk->thread.error_code = error_code;
@@ -588,7 +603,6 @@ do_sigbus:
 	force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
 }
 
-#ifndef CONFIG_X86_PAE
 void vmalloc_sync_all(void)
 {
 	/*
@@ -601,6 +615,9 @@ void vmalloc_sync_all(void)
 	static unsigned long start = TASK_SIZE;
 	unsigned long address;
 
+	if (SHARED_KERNEL_PMD)
+		return;
+
 	BUILD_BUG_ON(TASK_SIZE & ~PGDIR_MASK);
 	for (address = start; address >= TASK_SIZE; address += PGDIR_SIZE) {
 		if (!test_bit(pgd_index(address), insync)) {
@@ -623,4 +640,3 @@ void vmalloc_sync_all(void)
 			start = address + PGDIR_SIZE;
 	}
 }
-#endif
diff --git a/arch/i386/mm/highmem.c b/arch/i386/mm/highmem.c
index ac70d09df7e..ad8d86cc683 100644
--- a/arch/i386/mm/highmem.c
+++ b/arch/i386/mm/highmem.c
@@ -26,7 +26,7 @@ void kunmap(struct page *page)
  * However when holding an atomic kmap is is not legal to sleep, so atomic
  * kmaps are appropriate for short, tight code paths only.
  */
-void *kmap_atomic(struct page *page, enum km_type type)
+void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot)
 {
 	enum fixed_addresses idx;
 	unsigned long vaddr;
@@ -41,12 +41,17 @@ void *kmap_atomic(struct page *page, enum km_type type)
 		return page_address(page);
 
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
-	set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
+	set_pte(kmap_pte-idx, mk_pte(page, prot));
 	arch_flush_lazy_mmu_mode();
 
 	return (void*) vaddr;
 }
 
+void *kmap_atomic(struct page *page, enum km_type type)
+{
+	return kmap_atomic_prot(page, type, kmap_prot);
+}
+
 void kunmap_atomic(void *kvaddr, enum km_type type)
 {
 	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
@@ -67,6 +72,7 @@ void kunmap_atomic(void *kvaddr, enum km_type type)
 #endif
 	}
 
+	arch_flush_lazy_mmu_mode();
 	pagefault_enable();
 }
 
diff --git a/arch/i386/mm/init.c b/arch/i386/mm/init.c
index ae436882af7..dbe16f63a56 100644
--- a/arch/i386/mm/init.c
+++ b/arch/i386/mm/init.c
@@ -22,6 +22,7 @@
 #include <linux/init.h>
 #include <linux/highmem.h>
 #include <linux/pagemap.h>
+#include <linux/pfn.h>
 #include <linux/poison.h>
 #include <linux/bootmem.h>
 #include <linux/slab.h>
@@ -42,6 +43,7 @@
 #include <asm/tlb.h>
 #include <asm/tlbflush.h>
 #include <asm/sections.h>
+#include <asm/paravirt.h>
 
 unsigned int __VMALLOC_RESERVE = 128 << 20;
 
@@ -61,17 +63,18 @@ static pmd_t * __init one_md_table_init(pgd_t *pgd)
 	pmd_t *pmd_table;
 		
 #ifdef CONFIG_X86_PAE
-	pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
-	paravirt_alloc_pd(__pa(pmd_table) >> PAGE_SHIFT);
-	set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
-	pud = pud_offset(pgd, 0);
-	if (pmd_table != pmd_offset(pud, 0)) 
-		BUG();
-#else
+	if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
+		pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
+
+		paravirt_alloc_pd(__pa(pmd_table) >> PAGE_SHIFT);
+		set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
+		pud = pud_offset(pgd, 0);
+		if (pmd_table != pmd_offset(pud, 0))
+			BUG();
+	}
+#endif
 	pud = pud_offset(pgd, 0);
 	pmd_table = pmd_offset(pud, 0);
-#endif
-
 	return pmd_table;
 }
 
@@ -81,14 +84,12 @@ static pmd_t * __init one_md_table_init(pgd_t *pgd)
  */
 static pte_t * __init one_page_table_init(pmd_t *pmd)
 {
-	if (pmd_none(*pmd)) {
+	if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
 		pte_t *page_table = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
+
 		paravirt_alloc_pt(__pa(page_table) >> PAGE_SHIFT);
 		set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
-		if (page_table != pte_offset_kernel(pmd, 0))
-			BUG();	
-
-		return page_table;
+		BUG_ON(page_table != pte_offset_kernel(pmd, 0));
 	}
 	
 	return pte_offset_kernel(pmd, 0);
@@ -108,7 +109,6 @@ static pte_t * __init one_page_table_init(pmd_t *pmd)
 static void __init page_table_range_init (unsigned long start, unsigned long end, pgd_t *pgd_base)
 {
 	pgd_t *pgd;
-	pud_t *pud;
 	pmd_t *pmd;
 	int pgd_idx, pmd_idx;
 	unsigned long vaddr;
@@ -119,13 +119,10 @@ static void __init page_table_range_init (unsigned long start, unsigned long end
 	pgd = pgd_base + pgd_idx;
 
 	for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
-		if (pgd_none(*pgd)) 
-			one_md_table_init(pgd);
-		pud = pud_offset(pgd, vaddr);
-		pmd = pmd_offset(pud, vaddr);
+		pmd = one_md_table_init(pgd);
+		pmd = pmd + pmd_index(vaddr);
 		for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); pmd++, pmd_idx++) {
-			if (pmd_none(*pmd)) 
-				one_page_table_init(pmd);
+			one_page_table_init(pmd);
 
 			vaddr += PMD_SIZE;
 		}
@@ -167,20 +164,22 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
 			/* Map with big pages if possible, otherwise create normal page tables. */
 			if (cpu_has_pse) {
 				unsigned int address2 = (pfn + PTRS_PER_PTE - 1) * PAGE_SIZE + PAGE_OFFSET + PAGE_SIZE-1;
-
 				if (is_kernel_text(address) || is_kernel_text(address2))
 					set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
 				else
 					set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE));
+
 				pfn += PTRS_PER_PTE;
 			} else {
 				pte = one_page_table_init(pmd);
 
-				for (pte_ofs = 0; pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn; pte++, pfn++, pte_ofs++) {
-						if (is_kernel_text(address))
-							set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
-						else
-							set_pte(pte, pfn_pte(pfn, PAGE_KERNEL));
+				for (pte_ofs = 0;
+				     pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn;
+				     pte++, pfn++, pte_ofs++, address += PAGE_SIZE) {
+					if (is_kernel_text(address))
+						set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
+					else
+						set_pte(pte, pfn_pte(pfn, PAGE_KERNEL));
 				}
 			}
 		}
@@ -337,24 +336,78 @@ extern void __init remap_numa_kva(void);
 #define remap_numa_kva() do {} while (0)
 #endif
 
-static void __init pagetable_init (void)
+void __init native_pagetable_setup_start(pgd_t *base)
 {
-	unsigned long vaddr;
-	pgd_t *pgd_base = swapper_pg_dir;
-
 #ifdef CONFIG_X86_PAE
 	int i;
-	/* Init entries of the first-level page table to the zero page */
-	for (i = 0; i < PTRS_PER_PGD; i++)
-		set_pgd(pgd_base + i, __pgd(__pa(empty_zero_page) | _PAGE_PRESENT));
+
+	/*
+	 * Init entries of the first-level page table to the
+	 * zero page, if they haven't already been set up.
+	 *
+	 * In a normal native boot, we'll be running on a
+	 * pagetable rooted in swapper_pg_dir, but not in PAE
+	 * mode, so this will end up clobbering the mappings
+	 * for the lower 24Mbytes of the address space,
+	 * without affecting the kernel address space.
+	 */
+	for (i = 0; i < USER_PTRS_PER_PGD; i++)
+		set_pgd(&base[i],
+			__pgd(__pa(empty_zero_page) | _PAGE_PRESENT));
+
+	/* Make sure kernel address space is empty so that a pagetable
+	   will be allocated for it. */
+	memset(&base[USER_PTRS_PER_PGD], 0,
+	       KERNEL_PGD_PTRS * sizeof(pgd_t));
 #else
 	paravirt_alloc_pd(__pa(swapper_pg_dir) >> PAGE_SHIFT);
 #endif
+}
+
+void __init native_pagetable_setup_done(pgd_t *base)
+{
+#ifdef CONFIG_X86_PAE
+	/*
+	 * Add low memory identity-mappings - SMP needs it when
+	 * starting up on an AP from real-mode. In the non-PAE
+	 * case we already have these mappings through head.S.
+	 * All user-space mappings are explicitly cleared after
+	 * SMP startup.
+	 */
+	set_pgd(&base[0], base[USER_PTRS_PER_PGD]);
+#endif
+}
+
+/*
+ * Build a proper pagetable for the kernel mappings.  Up until this
+ * point, we've been running on some set of pagetables constructed by
+ * the boot process.
+ *
+ * If we're booting on native hardware, this will be a pagetable
+ * constructed in arch/i386/kernel/head.S, and not running in PAE mode
+ * (even if we'll end up running in PAE).  The root of the pagetable
+ * will be swapper_pg_dir.
+ *
+ * If we're booting paravirtualized under a hypervisor, then there are
+ * more options: we may already be running PAE, and the pagetable may
+ * or may not be based in swapper_pg_dir.  In any case,
+ * paravirt_pagetable_setup_start() will set up swapper_pg_dir
+ * appropriately for the rest of the initialization to work.
+ *
+ * In general, pagetable_init() assumes that the pagetable may already
+ * be partially populated, and so it avoids stomping on any existing
+ * mappings.
+ */
+static void __init pagetable_init (void)
+{
+	unsigned long vaddr, end;
+	pgd_t *pgd_base = swapper_pg_dir;
+
+	paravirt_pagetable_setup_start(pgd_base);
 
 	/* Enable PSE if available */
-	if (cpu_has_pse) {
+	if (cpu_has_pse)
 		set_in_cr4(X86_CR4_PSE);
-	}
 
 	/* Enable PGE if available */
 	if (cpu_has_pge) {
@@ -371,20 +424,12 @@ static void __init pagetable_init (void)
 	 * created - mappings will be set by set_fixmap():
 	 */
 	vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
-	page_table_range_init(vaddr, 0, pgd_base);
+	end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
+	page_table_range_init(vaddr, end, pgd_base);
 
 	permanent_kmaps_init(pgd_base);
 
-#ifdef CONFIG_X86_PAE
-	/*
-	 * Add low memory identity-mappings - SMP needs it when
-	 * starting up on an AP from real-mode. In the non-PAE
-	 * case we already have these mappings through head.S.
-	 * All user-space mappings are explicitly cleared after
-	 * SMP startup.
-	 */
-	set_pgd(&pgd_base[0], pgd_base[USER_PTRS_PER_PGD]);
-#endif
+	paravirt_pagetable_setup_done(pgd_base);
 }
 
 #if defined(CONFIG_SOFTWARE_SUSPEND) || defined(CONFIG_ACPI_SLEEP)
@@ -700,6 +745,8 @@ struct kmem_cache *pmd_cache;
 
 void __init pgtable_cache_init(void)
 {
+	size_t pgd_size = PTRS_PER_PGD*sizeof(pgd_t);
+
 	if (PTRS_PER_PMD > 1) {
 		pmd_cache = kmem_cache_create("pmd",
 					PTRS_PER_PMD*sizeof(pmd_t),
@@ -709,13 +756,23 @@ void __init pgtable_cache_init(void)
 					NULL);
 		if (!pmd_cache)
 			panic("pgtable_cache_init(): cannot create pmd cache");
+
+		if (!SHARED_KERNEL_PMD) {
+			/* If we're in PAE mode and have a non-shared
+			   kernel pmd, then the pgd size must be a
+			   page size.  This is because the pgd_list
+			   links through the page structure, so there
+			   can only be one pgd per page for this to
+			   work. */
+			pgd_size = PAGE_SIZE;
+		}
 	}
 	pgd_cache = kmem_cache_create("pgd",
-				PTRS_PER_PGD*sizeof(pgd_t),
-				PTRS_PER_PGD*sizeof(pgd_t),
+				pgd_size,
+				pgd_size,
 				0,
 				pgd_ctor,
-				PTRS_PER_PMD == 1 ? pgd_dtor : NULL);
+				(!SHARED_KERNEL_PMD) ? pgd_dtor : NULL);
 	if (!pgd_cache)
 		panic("pgtable_cache_init(): Cannot create pgd cache");
 }
@@ -751,13 +808,25 @@ static int noinline do_test_wp_bit(void)
 
 void mark_rodata_ro(void)
 {
-	unsigned long addr = (unsigned long)__start_rodata;
+	unsigned long start = PFN_ALIGN(_text);
+	unsigned long size = PFN_ALIGN(_etext) - start;
 
-	for (; addr < (unsigned long)__end_rodata; addr += PAGE_SIZE)
-		change_page_attr(virt_to_page(addr), 1, PAGE_KERNEL_RO);
+#ifdef CONFIG_HOTPLUG_CPU
+	/* It must still be possible to apply SMP alternatives. */
+	if (num_possible_cpus() <= 1)
+#endif
+	{
+		change_page_attr(virt_to_page(start),
+		                 size >> PAGE_SHIFT, PAGE_KERNEL_RX);
+		printk("Write protecting the kernel text: %luk\n", size >> 10);
+	}
 
-	printk("Write protecting the kernel read-only data: %uk\n",
-			(__end_rodata - __start_rodata) >> 10);
+	start += size;
+	size = (unsigned long)__end_rodata - start;
+	change_page_attr(virt_to_page(start),
+	                 size >> PAGE_SHIFT, PAGE_KERNEL_RO);
+	printk("Write protecting the kernel read-only data: %luk\n",
+	       size >> 10);
 
 	/*
 	 * change_page_attr() requires a global_flush_tlb() call after it.
@@ -774,26 +843,27 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end)
 	unsigned long addr;
 
 	for (addr = begin; addr < end; addr += PAGE_SIZE) {
-		ClearPageReserved(virt_to_page(addr));
-		init_page_count(virt_to_page(addr));
-		memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
-		free_page(addr);
+		struct page *page = pfn_to_page(addr >> PAGE_SHIFT);
+		ClearPageReserved(page);
+		init_page_count(page);
+		memset(page_address(page), POISON_FREE_INITMEM, PAGE_SIZE);
+		__free_page(page);
 		totalram_pages++;
 	}
-	printk(KERN_INFO "Freeing %s: %ldk freed\n", what, (end - begin) >> 10);
+	printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
 }
 
 void free_initmem(void)
 {
 	free_init_pages("unused kernel memory",
-			(unsigned long)(&__init_begin),
-			(unsigned long)(&__init_end));
+			__pa_symbol(&__init_begin),
+			__pa_symbol(&__init_end));
 }
 
 #ifdef CONFIG_BLK_DEV_INITRD
 void free_initrd_mem(unsigned long start, unsigned long end)
 {
-	free_init_pages("initrd memory", start, end);
+	free_init_pages("initrd memory", __pa(start), __pa(end));
 }
 #endif
 
diff --git a/arch/i386/mm/pageattr.c b/arch/i386/mm/pageattr.c
index 412ebbd8adb..47bd477c8ec 100644
--- a/arch/i386/mm/pageattr.c
+++ b/arch/i386/mm/pageattr.c
@@ -91,7 +91,7 @@ static void set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
 	unsigned long flags;
 
 	set_pte_atomic(kpte, pte); 	/* change init_mm */
-	if (PTRS_PER_PMD > 1)
+	if (SHARED_KERNEL_PMD)
 		return;
 
 	spin_lock_irqsave(&pgd_lock, flags);
@@ -142,7 +142,7 @@ __change_page_attr(struct page *page, pgprot_t prot)
 		return -EINVAL;
 	kpte_page = virt_to_page(kpte);
 	if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL)) { 
-		if ((pte_val(*kpte) & _PAGE_PSE) == 0) { 
+		if (!pte_huge(*kpte)) {
 			set_pte_atomic(kpte, mk_pte(page, prot)); 
 		} else {
 			pgprot_t ref_prot;
@@ -158,7 +158,7 @@ __change_page_attr(struct page *page, pgprot_t prot)
 			kpte_page = split;
 		}
 		page_private(kpte_page)++;
-	} else if ((pte_val(*kpte) & _PAGE_PSE) == 0) { 
+	} else if (!pte_huge(*kpte)) {
 		set_pte_atomic(kpte, mk_pte(page, PAGE_KERNEL));
 		BUG_ON(page_private(kpte_page) == 0);
 		page_private(kpte_page)--;
diff --git a/arch/i386/mm/pgtable.c b/arch/i386/mm/pgtable.c
index fa0cfbd551e..9a96c164742 100644
--- a/arch/i386/mm/pgtable.c
+++ b/arch/i386/mm/pgtable.c
@@ -144,10 +144,8 @@ void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
 }
 
 static int fixmaps;
-#ifndef CONFIG_COMPAT_VDSO
 unsigned long __FIXADDR_TOP = 0xfffff000;
 EXPORT_SYMBOL(__FIXADDR_TOP);
-#endif
 
 void __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t flags)
 {
@@ -173,12 +171,8 @@ void reserve_top_address(unsigned long reserve)
 	BUG_ON(fixmaps > 0);
 	printk(KERN_INFO "Reserving virtual address space above 0x%08x\n",
 	       (int)-reserve);
-#ifdef CONFIG_COMPAT_VDSO
-	BUG_ON(reserve != 0);
-#else
 	__FIXADDR_TOP = -reserve - PAGE_SIZE;
 	__VMALLOC_RESERVE += reserve;
-#endif
 }
 
 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
@@ -238,42 +232,92 @@ static inline void pgd_list_del(pgd_t *pgd)
 		set_page_private(next, (unsigned long)pprev);
 }
 
+#if (PTRS_PER_PMD == 1)
+/* Non-PAE pgd constructor */
 void pgd_ctor(void *pgd, struct kmem_cache *cache, unsigned long unused)
 {
 	unsigned long flags;
 
-	if (PTRS_PER_PMD == 1) {
-		memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
-		spin_lock_irqsave(&pgd_lock, flags);
-	}
+	/* !PAE, no pagetable sharing */
+	memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
+
+	spin_lock_irqsave(&pgd_lock, flags);
 
+	/* must happen under lock */
 	clone_pgd_range((pgd_t *)pgd + USER_PTRS_PER_PGD,
 			swapper_pg_dir + USER_PTRS_PER_PGD,
 			KERNEL_PGD_PTRS);
-
-	if (PTRS_PER_PMD > 1)
-		return;
-
-	/* must happen under lock */
 	paravirt_alloc_pd_clone(__pa(pgd) >> PAGE_SHIFT,
-			__pa(swapper_pg_dir) >> PAGE_SHIFT,
-			USER_PTRS_PER_PGD, PTRS_PER_PGD - USER_PTRS_PER_PGD);
-
+				__pa(swapper_pg_dir) >> PAGE_SHIFT,
+				USER_PTRS_PER_PGD,
+				KERNEL_PGD_PTRS);
 	pgd_list_add(pgd);
 	spin_unlock_irqrestore(&pgd_lock, flags);
 }
+#else  /* PTRS_PER_PMD > 1 */
+/* PAE pgd constructor */
+void pgd_ctor(void *pgd, struct kmem_cache *cache, unsigned long unused)
+{
+	/* PAE, kernel PMD may be shared */
+
+	if (SHARED_KERNEL_PMD) {
+		clone_pgd_range((pgd_t *)pgd + USER_PTRS_PER_PGD,
+				swapper_pg_dir + USER_PTRS_PER_PGD,
+				KERNEL_PGD_PTRS);
+	} else {
+		unsigned long flags;
+
+		memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
+		spin_lock_irqsave(&pgd_lock, flags);
+		pgd_list_add(pgd);
+		spin_unlock_irqrestore(&pgd_lock, flags);
+	}
+}
+#endif	/* PTRS_PER_PMD */
 
-/* never called when PTRS_PER_PMD > 1 */
 void pgd_dtor(void *pgd, struct kmem_cache *cache, unsigned long unused)
 {
 	unsigned long flags; /* can be called from interrupt context */
 
+	BUG_ON(SHARED_KERNEL_PMD);
+
 	paravirt_release_pd(__pa(pgd) >> PAGE_SHIFT);
 	spin_lock_irqsave(&pgd_lock, flags);
 	pgd_list_del(pgd);
 	spin_unlock_irqrestore(&pgd_lock, flags);
 }
 
+#define UNSHARED_PTRS_PER_PGD				\
+	(SHARED_KERNEL_PMD ? USER_PTRS_PER_PGD : PTRS_PER_PGD)
+
+/* If we allocate a pmd for part of the kernel address space, then
+   make sure its initialized with the appropriate kernel mappings.
+   Otherwise use a cached zeroed pmd.  */
+static pmd_t *pmd_cache_alloc(int idx)
+{
+	pmd_t *pmd;
+
+	if (idx >= USER_PTRS_PER_PGD) {
+		pmd = (pmd_t *)__get_free_page(GFP_KERNEL);
+
+		if (pmd)
+			memcpy(pmd,
+			       (void *)pgd_page_vaddr(swapper_pg_dir[idx]),
+			       sizeof(pmd_t) * PTRS_PER_PMD);
+	} else
+		pmd = kmem_cache_alloc(pmd_cache, GFP_KERNEL);
+
+	return pmd;
+}
+
+static void pmd_cache_free(pmd_t *pmd, int idx)
+{
+	if (idx >= USER_PTRS_PER_PGD)
+		free_page((unsigned long)pmd);
+	else
+		kmem_cache_free(pmd_cache, pmd);
+}
+
 pgd_t *pgd_alloc(struct mm_struct *mm)
 {
 	int i;
@@ -282,10 +326,12 @@ pgd_t *pgd_alloc(struct mm_struct *mm)
 	if (PTRS_PER_PMD == 1 || !pgd)
 		return pgd;
 
-	for (i = 0; i < USER_PTRS_PER_PGD; ++i) {
-		pmd_t *pmd = kmem_cache_alloc(pmd_cache, GFP_KERNEL);
+ 	for (i = 0; i < UNSHARED_PTRS_PER_PGD; ++i) {
+		pmd_t *pmd = pmd_cache_alloc(i);
+
 		if (!pmd)
 			goto out_oom;
+
 		paravirt_alloc_pd(__pa(pmd) >> PAGE_SHIFT);
 		set_pgd(&pgd[i], __pgd(1 + __pa(pmd)));
 	}
@@ -296,7 +342,7 @@ out_oom:
 		pgd_t pgdent = pgd[i];
 		void* pmd = (void *)__va(pgd_val(pgdent)-1);
 		paravirt_release_pd(__pa(pmd) >> PAGE_SHIFT);
-		kmem_cache_free(pmd_cache, pmd);
+		pmd_cache_free(pmd, i);
 	}
 	kmem_cache_free(pgd_cache, pgd);
 	return NULL;
@@ -308,11 +354,11 @@ void pgd_free(pgd_t *pgd)
 
 	/* in the PAE case user pgd entries are overwritten before usage */
 	if (PTRS_PER_PMD > 1)
-		for (i = 0; i < USER_PTRS_PER_PGD; ++i) {
+		for (i = 0; i < UNSHARED_PTRS_PER_PGD; ++i) {
 			pgd_t pgdent = pgd[i];
 			void* pmd = (void *)__va(pgd_val(pgdent)-1);
 			paravirt_release_pd(__pa(pmd) >> PAGE_SHIFT);
-			kmem_cache_free(pmd_cache, pmd);
+			pmd_cache_free(pmd, i);
 		}
 	/* in the non-PAE case, free_pgtables() clears user pgd entries */
 	kmem_cache_free(pgd_cache, pgd);