Merge branch 'pgtable-layout-rewrite' into for-v5.7

Peter Zijlstra <peterz@infradead.org> wrote:

   "In order to facilitate Will's READ_ONCE() patches, we need to fix
    m68k/motorola to not have a giant pmd_t. These patches do so and are
    tested using ARAnyM/68040."

arch/m68k/include/asm/mcf_pgalloc.h

@@ -28,21 +28,22 @@ extern inline pmd_t *pmd_alloc_kernel(pgd_t *pgd, unsigned long address)
 	return (pmd_t *) pgd;
 }
 
-#define pmd_populate(mm, pmd, page) (pmd_val(*pmd) = \
-	(unsigned long)(page_address(page)))
+#define pmd_populate(mm, pmd, pte) (pmd_val(*pmd) = (unsigned long)(pte))
 
-#define pmd_populate_kernel(mm, pmd, pte) (pmd_val(*pmd) = (unsigned long)(pte))
+#define pmd_populate_kernel pmd_populate
 
-#define pmd_pgtable(pmd) pmd_page(pmd)
+#define pmd_pgtable(pmd) pfn_to_virt(pmd_val(pmd) >> PAGE_SHIFT)
 
-static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t page,
+static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pgtable,
 				  unsigned long address)
 {
+	struct page *page = virt_to_page(pgtable);
+
 	pgtable_pte_page_dtor(page);
 	__free_page(page);
 }
 
-static inline struct page *pte_alloc_one(struct mm_struct *mm)
+static inline pgtable_t pte_alloc_one(struct mm_struct *mm)
 {
 	struct page *page = alloc_pages(GFP_DMA, 0);
 	pte_t *pte;
@@ -54,20 +55,16 @@ static inline struct page *pte_alloc_one(struct mm_struct *mm)
 		return NULL;
 	}
 
-	pte = kmap(page);
-	if (pte) {
+	pte = page_address(page);
 	clear_page(pte);
-		__flush_page_to_ram(pte);
-		flush_tlb_kernel_page(pte);
-		nocache_page(pte);
-	}
-	kunmap(page);
 
-	return page;
+	return pte;
 }
 
-static inline void pte_free(struct mm_struct *mm, struct page *page)
+static inline void pte_free(struct mm_struct *mm, pgtable_t pgtable)
 {
+	struct page *page = virt_to_page(pgtable);
+
 	pgtable_pte_page_dtor(page);
 	__free_page(page);
 }
@@ -90,7 +87,7 @@ static inline pgd_t *pgd_alloc(struct mm_struct *mm)
 	new_pgd = (pgd_t *)__get_free_page(GFP_DMA | __GFP_NOWARN);
 	if (!new_pgd)
 		return NULL;
-	memcpy(new_pgd, swapper_pg_dir, PAGE_SIZE);
+	memcpy(new_pgd, swapper_pg_dir, PTRS_PER_PGD * sizeof(pgd_t));
 	memset(new_pgd, 0, PAGE_OFFSET >> PGDIR_SHIFT);
 	return new_pgd;
 }

arch/m68k/include/asm/motorola_pgalloc.h

@@ -5,93 +5,71 @@
 #include <asm/tlb.h>
 #include <asm/tlbflush.h>
 
-extern pmd_t *get_pointer_table(void);
-extern int free_pointer_table(pmd_t *);
+extern void mmu_page_ctor(void *page);
+extern void mmu_page_dtor(void *page);
 
-static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
-{
-	pte_t *pte;
+enum m68k_table_types {
+	TABLE_PGD = 0,
+	TABLE_PMD = 0, /* same size as PGD */
+	TABLE_PTE = 1,
+};
 
-	pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
-	if (pte) {
-		__flush_page_to_ram(pte);
-		flush_tlb_kernel_page(pte);
-		nocache_page(pte);
-	}
+extern void init_pointer_table(void *table, int type);
+extern void *get_pointer_table(int type);
+extern int free_pointer_table(void *table, int type);
 
-	return pte;
+static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
+{
+	return get_pointer_table(TABLE_PTE);
 }
 
 static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
 {
-	cache_page(pte);
-	free_page((unsigned long) pte);
+	free_pointer_table(pte, TABLE_PTE);
 }
 
 static inline pgtable_t pte_alloc_one(struct mm_struct *mm)
 {
-	struct page *page;
-	pte_t *pte;
-
-	page = alloc_pages(GFP_KERNEL|__GFP_ZERO, 0);
-	if(!page)
-		return NULL;
-	if (!pgtable_pte_page_ctor(page)) {
-		__free_page(page);
-		return NULL;
-	}
-
-	pte = kmap(page);
-	__flush_page_to_ram(pte);
-	flush_tlb_kernel_page(pte);
-	nocache_page(pte);
-	kunmap(page);
-	return page;
+	return get_pointer_table(TABLE_PTE);
 }
 
-static inline void pte_free(struct mm_struct *mm, pgtable_t page)
+static inline void pte_free(struct mm_struct *mm, pgtable_t pgtable)
 {
-	pgtable_pte_page_dtor(page);
-	cache_page(kmap(page));
-	kunmap(page);
-	__free_page(page);
+	free_pointer_table(pgtable, TABLE_PTE);
 }
 
-static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t page,
+static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pgtable,
 				  unsigned long address)
 {
-	pgtable_pte_page_dtor(page);
-	cache_page(kmap(page));
-	kunmap(page);
-	__free_page(page);
+	free_pointer_table(pgtable, TABLE_PTE);
 }
 
 
 static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
 {
-	return get_pointer_table();
+	return get_pointer_table(TABLE_PMD);
 }
 
 static inline int pmd_free(struct mm_struct *mm, pmd_t *pmd)
 {
-	return free_pointer_table(pmd);
+	return free_pointer_table(pmd, TABLE_PMD);
 }
 
 static inline int __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd,
 				 unsigned long address)
 {
-	return free_pointer_table(pmd);
+	return free_pointer_table(pmd, TABLE_PMD);
 }
 
 
 static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 {
-	pmd_free(mm, (pmd_t *)pgd);
+	free_pointer_table(pgd, TABLE_PGD);
 }
 
 static inline pgd_t *pgd_alloc(struct mm_struct *mm)
 {
-	return (pgd_t *)get_pointer_table();
+	return get_pointer_table(TABLE_PGD);
 }
 
 
@@ -102,9 +80,9 @@ static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *
 
 static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd, pgtable_t page)
 {
-	pmd_set(pmd, page_address(page));
+	pmd_set(pmd, page);
 }
-#define pmd_pgtable(pmd) pmd_page(pmd)
+#define pmd_pgtable(pmd) ((pgtable_t)__pmd_page(pmd))
 
 static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
 {

arch/m68k/include/asm/motorola_pgtable.h

@@ -23,7 +23,18 @@
 #define _DESCTYPE_MASK	0x003
 
 #define _CACHEMASK040	(~0x060)
-#define _TABLE_MASK	(0xfffffe00)
+
+/*
+ * Currently set to the minimum alignment of table pointers (256 bytes).
+ * The hardware only uses the low 4 bits for state:
+ *
+ *    3 - Used
+ *    2 - Write Protected
+ *  0,1 - Descriptor Type
+ *
+ * and has the rest of the bits reserved.
+ */
+#define _TABLE_MASK	(0xffffff00)
 
 #define _PAGE_TABLE	(_PAGE_SHORT)
 #define _PAGE_CHG_MASK  (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_NOCACHE)
@@ -108,13 +119,7 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 
 static inline void pmd_set(pmd_t *pmdp, pte_t *ptep)
 {
-	unsigned long ptbl = virt_to_phys(ptep) | _PAGE_TABLE | _PAGE_ACCESSED;
-	unsigned long *ptr = pmdp->pmd;
-	short i = 16;
-	while (--i >= 0) {
-		*ptr++ = ptbl;
-		ptbl += (sizeof(pte_t)*PTRS_PER_PTE/16);
-	}
+	pmd_val(*pmdp) = virt_to_phys(ptep) | _PAGE_TABLE | _PAGE_ACCESSED;
 }
 
 static inline void pud_set(pud_t *pudp, pmd_t *pmdp)
@@ -138,13 +143,14 @@ static inline void pud_set(pud_t *pudp, pmd_t *pmdp)
 #define pmd_none(pmd)		(!pmd_val(pmd))
 #define pmd_bad(pmd)		((pmd_val(pmd) & _DESCTYPE_MASK) != _PAGE_TABLE)
 #define pmd_present(pmd)	(pmd_val(pmd) & _PAGE_TABLE)
-#define pmd_clear(pmdp) ({			\
-	unsigned long *__ptr = pmdp->pmd;	\
-	short __i = 16;				\
-	while (--__i >= 0)			\
-		*__ptr++ = 0;			\
-})
-#define pmd_page(pmd)		virt_to_page(__va(pmd_val(pmd)))
+#define pmd_clear(pmdp)		({ pmd_val(*pmdp) = 0; })
+
+/*
+ * m68k does not have huge pages (020/030 actually could), but generic code
+ * expects pmd_page() to exists, only to then DCE it all. Provide a dummy to
+ * make the compiler happy.
+ */
+#define pmd_page(pmd)		NULL
 
 
 #define pud_none(pud)		(!pud_val(pud))

arch/m68k/include/asm/page.h

@@ -22,15 +22,25 @@
  * These are used to make use of C type-checking..
  */
 #if !defined(CONFIG_MMU) || CONFIG_PGTABLE_LEVELS == 3
-typedef struct { unsigned long pmd[16]; } pmd_t;
-#define pmd_val(x)	((&x)->pmd[0])
-#define __pmd(x)	((pmd_t) { { (x) }, })
+typedef struct { unsigned long pmd; } pmd_t;
+#define pmd_val(x)	((&x)->pmd)
+#define __pmd(x)	((pmd_t) { (x) } )
 #endif
 
 typedef struct { unsigned long pte; } pte_t;
 typedef struct { unsigned long pgd; } pgd_t;
 typedef struct { unsigned long pgprot; } pgprot_t;
+
+#if defined(CONFIG_SUN3)
+/*
+ * Sun3 still uses the asm-generic/pgalloc.h code and thus needs this
+ * definition. It would be possible to unify Sun3 and ColdFire pgalloc and have
+ * all of m68k use the same type.
+ */
 typedef struct page *pgtable_t;
+#else
+typedef pte_t *pgtable_t;
+#endif
 
 #define pte_val(x)	((x).pte)
 #define pgd_val(x)	((x).pgd)

arch/m68k/include/asm/pgtable_mm.h

@@ -36,7 +36,7 @@
 
 /* PMD_SHIFT determines the size of the area a second-level page table can map */
 #if CONFIG_PGTABLE_LEVELS == 3
-#define PMD_SHIFT	22
+#define PMD_SHIFT	18
 #endif
 #define PMD_SIZE	(1UL << PMD_SHIFT)
 #define PMD_MASK	(~(PMD_SIZE-1))
@@ -67,8 +67,8 @@
 #define PTRS_PER_PMD	1
 #define PTRS_PER_PGD	1024
 #else
-#define PTRS_PER_PTE	1024
-#define PTRS_PER_PMD	8
+#define PTRS_PER_PTE	64
+#define PTRS_PER_PMD	128
 #define PTRS_PER_PGD	128
 #endif
 #define USER_PTRS_PER_PGD	(TASK_SIZE/PGDIR_SIZE)
@@ -76,8 +76,8 @@
 
 /* Virtual address region for use by kernel_map() */
 #ifdef CONFIG_SUN3
-#define KMAP_START     0x0DC00000
-#define KMAP_END       0x0E000000
+#define KMAP_START	0x0dc00000
+#define KMAP_END	0x0e000000
 #elif defined(CONFIG_COLDFIRE)
 #define KMAP_START	0xe0000000
 #define KMAP_END	0xf0000000

arch/m68k/mm/init.c

@@ -40,11 +40,6 @@
 void *empty_zero_page;
 EXPORT_SYMBOL(empty_zero_page);
 
-#if !defined(CONFIG_SUN3) && !defined(CONFIG_COLDFIRE)
-extern void init_pointer_table(unsigned long ptable);
-extern pmd_t *zero_pgtable;
-#endif
-
 #ifdef CONFIG_MMU
 
 pg_data_t pg_data_map[MAX_NUMNODES];
@@ -125,20 +120,31 @@ void free_initmem(void)
 static inline void init_pointer_tables(void)
 {
 #if defined(CONFIG_MMU) && !defined(CONFIG_SUN3) && !defined(CONFIG_COLDFIRE)
-	int i;
+	int i, j;
 
 	/* insert pointer tables allocated so far into the tablelist */
-	init_pointer_table((unsigned long)kernel_pg_dir);
+	init_pointer_table(kernel_pg_dir, TABLE_PGD);
 	for (i = 0; i < PTRS_PER_PGD; i++) {
-		pud_t *pud = (pud_t *)(&kernel_pg_dir[i]);
+		pud_t *pud = (pud_t *)&kernel_pg_dir[i];
+		pmd_t *pmd_dir;
 
-		if (pud_present(*pud))
-			init_pointer_table(pgd_page_vaddr(kernel_pg_dir[i]));
-	}
+		if (!pud_present(*pud))
+			continue;
+
+		pmd_dir = (pmd_t *)pgd_page_vaddr(kernel_pg_dir[i]);
+		init_pointer_table(pmd_dir, TABLE_PMD);
 
-	/* insert also pointer table that we used to unmap the zero page */
-	if (zero_pgtable)
-		init_pointer_table((unsigned long)zero_pgtable);
+		for (j = 0; j < PTRS_PER_PMD; j++) {
+			pmd_t *pmd = &pmd_dir[j];
+			pte_t *pte_dir;
+
+			if (!pmd_present(*pmd))
+				continue;
+
+			pte_dir = (pte_t *)__pmd_page(*pmd);
+			init_pointer_table(pte_dir, TABLE_PTE);
+		}
+	}
 #endif
 }
 

arch/m68k/mm/kmap.c

@@ -24,8 +24,6 @@
 
 #undef DEBUG
 
-#define PTRTREESIZE	(256*1024)
-
 /*
  * For 040/060 we can use the virtual memory area like other architectures,
  * but for 020/030 we want to use early termination page descriptors and we
@@ -50,7 +48,7 @@ static inline void free_io_area(void *addr)
 
 #else
 
-#define IO_SIZE		(256*1024)
+#define IO_SIZE		PMD_SIZE
 
 static struct vm_struct *iolist;
 
@@ -81,14 +79,13 @@ static void __free_io_area(void *addr, unsigned long size)
 
 #if CONFIG_PGTABLE_LEVELS == 3
 		if (CPU_IS_020_OR_030) {
-			int pmd_off = (virtaddr/PTRTREESIZE) & 15;
-			int pmd_type = pmd_dir->pmd[pmd_off] & _DESCTYPE_MASK;
+			int pmd_type = pmd_val(*pmd_dir) & _DESCTYPE_MASK;
 
 			if (pmd_type == _PAGE_PRESENT) {
-				pmd_dir->pmd[pmd_off] = 0;
-				virtaddr += PTRTREESIZE;
-				size -= PTRTREESIZE;
-				continue;
+				pmd_clear(pmd_dir);
+				virtaddr += PMD_SIZE;
+				size -= PMD_SIZE;
+
 			} else if (pmd_type == 0)
 				continue;
 		}
@@ -249,7 +246,7 @@ void __iomem *__ioremap(unsigned long physaddr, unsigned long size, int cachefla
 
 	while ((long)size > 0) {
 #ifdef DEBUG
-		if (!(virtaddr & (PTRTREESIZE-1)))
+		if (!(virtaddr & (PMD_SIZE-1)))
 			printk ("\npa=%#lx va=%#lx ", physaddr, virtaddr);
 #endif
 		pgd_dir = pgd_offset_k(virtaddr);
@@ -263,10 +260,10 @@ void __iomem *__ioremap(unsigned long physaddr, unsigned long size, int cachefla
 
 #if CONFIG_PGTABLE_LEVELS == 3
 		if (CPU_IS_020_OR_030) {
-			pmd_dir->pmd[(virtaddr/PTRTREESIZE) & 15] = physaddr;
-			physaddr += PTRTREESIZE;
-			virtaddr += PTRTREESIZE;
-			size -= PTRTREESIZE;
+			pmd_val(*pmd_dir) = physaddr;
+			physaddr += PMD_SIZE;
+			virtaddr += PMD_SIZE;
+			size -= PMD_SIZE;
 		} else
 #endif
 		{
@@ -367,13 +364,12 @@ void kernel_set_cachemode(void *addr, unsigned long size, int cmode)
 
 #if CONFIG_PGTABLE_LEVELS == 3
 		if (CPU_IS_020_OR_030) {
-			int pmd_off = (virtaddr/PTRTREESIZE) & 15;
+			unsigned long pmd = pmd_val(*pmd_dir);
 
-			if ((pmd_dir->pmd[pmd_off] & _DESCTYPE_MASK) == _PAGE_PRESENT) {
-				pmd_dir->pmd[pmd_off] = (pmd_dir->pmd[pmd_off] &
-							 _CACHEMASK040) | cmode;
-				virtaddr += PTRTREESIZE;
-				size -= PTRTREESIZE;
+			if ((pmd & _DESCTYPE_MASK) == _PAGE_PRESENT) {
+				*pmd_dir = __pmd((pmd & _CACHEMASK040) | cmode);
+				virtaddr += PMD_SIZE;
+				size -= PMD_SIZE;
 				continue;
 			}
 		}

arch/m68k/mm/memory.c

@@ -22,109 +22,6 @@
 #include <asm/machdep.h>
 
 
-/* ++andreas: {get,free}_pointer_table rewritten to use unused fields from
-   struct page instead of separately kmalloced struct.  Stolen from
-   arch/sparc/mm/srmmu.c ... */
-
-typedef struct list_head ptable_desc;
-static LIST_HEAD(ptable_list);
-
-#define PD_PTABLE(page) ((ptable_desc *)&(virt_to_page(page)->lru))
-#define PD_PAGE(ptable) (list_entry(ptable, struct page, lru))
-#define PD_MARKBITS(dp) (*(unsigned char *)&PD_PAGE(dp)->index)
-
-#define PTABLE_SIZE (PTRS_PER_PMD * sizeof(pmd_t))
-
-void __init init_pointer_table(unsigned long ptable)
-{
-	ptable_desc *dp;
-	unsigned long page = ptable & PAGE_MASK;
-	unsigned char mask = 1 << ((ptable - page)/PTABLE_SIZE);
-
-	dp = PD_PTABLE(page);
-	if (!(PD_MARKBITS(dp) & mask)) {
-		PD_MARKBITS(dp) = 0xff;
-		list_add(dp, &ptable_list);
-	}
-
-	PD_MARKBITS(dp) &= ~mask;
-	pr_debug("init_pointer_table: %lx, %x\n", ptable, PD_MARKBITS(dp));
-
-	/* unreserve the page so it's possible to free that page */
-	__ClearPageReserved(PD_PAGE(dp));
-	init_page_count(PD_PAGE(dp));
-
-	return;
-}
-
-pmd_t *get_pointer_table (void)
-{
-	ptable_desc *dp = ptable_list.next;
-	unsigned char mask = PD_MARKBITS (dp);
-	unsigned char tmp;
-	unsigned int off;
-
-	/*
-	 * For a pointer table for a user process address space, a
-	 * table is taken from a page allocated for the purpose.  Each
-	 * page can hold 8 pointer tables.  The page is remapped in
-	 * virtual address space to be noncacheable.
-	 */
-	if (mask == 0) {
-		void *page;
-		ptable_desc *new;
-
-		if (!(page = (void *)get_zeroed_page(GFP_KERNEL)))
-			return NULL;
-
-		flush_tlb_kernel_page(page);
-		nocache_page(page);
-
-		new = PD_PTABLE(page);
-		PD_MARKBITS(new) = 0xfe;
-		list_add_tail(new, dp);
-
-		return (pmd_t *)page;
-	}
-
-	for (tmp = 1, off = 0; (mask & tmp) == 0; tmp <<= 1, off += PTABLE_SIZE)
-		;
-	PD_MARKBITS(dp) = mask & ~tmp;
-	if (!PD_MARKBITS(dp)) {
-		/* move to end of list */
-		list_move_tail(dp, &ptable_list);
-	}
-	return (pmd_t *) (page_address(PD_PAGE(dp)) + off);
-}
-
-int free_pointer_table (pmd_t *ptable)
-{
-	ptable_desc *dp;
-	unsigned long page = (unsigned long)ptable & PAGE_MASK;
-	unsigned char mask = 1 << (((unsigned long)ptable - page)/PTABLE_SIZE);
-
-	dp = PD_PTABLE(page);
-	if (PD_MARKBITS (dp) & mask)
-		panic ("table already free!");
-
-	PD_MARKBITS (dp) |= mask;
-
-	if (PD_MARKBITS(dp) == 0xff) {
-		/* all tables in page are free, free page */
-		list_del(dp);
-		cache_page((void *)page);
-		free_page (page);
-		return 1;
-	} else if (ptable_list.next != dp) {
-		/*
-		 * move this descriptor to the front of the list, since
-		 * it has one or more free tables.
-		 */
-		list_move(dp, &ptable_list);
-	}
-	return 0;
-}
-
 /* invalidate page in both caches */
 static inline void clear040(unsigned long paddr)
 {

arch/m68k/mm/motorola.c

@@ -45,34 +45,185 @@ unsigned long mm_cachebits;
 EXPORT_SYMBOL(mm_cachebits);
 #endif
 
+
+/*
+ * Motorola 680x0 user's manual recommends using uncached memory for address
+ * translation tables.
+ *
+ * Seeing how the MMU can be external on (some of) these chips, that seems like
+ * a very important recommendation to follow. Provide some helpers to combat
+ * 'variation' amongst the users of this.
+ */
+
+void mmu_page_ctor(void *page)
+{
+	__flush_page_to_ram(page);
+	flush_tlb_kernel_page(page);
+	nocache_page(page);
+}
+
+void mmu_page_dtor(void *page)
+{
+	cache_page(page);
+}
+
+/* ++andreas: {get,free}_pointer_table rewritten to use unused fields from
+   struct page instead of separately kmalloced struct.  Stolen from
+   arch/sparc/mm/srmmu.c ... */
+
+typedef struct list_head ptable_desc;
+
+static struct list_head ptable_list[2] = {
+	LIST_HEAD_INIT(ptable_list[0]),
+	LIST_HEAD_INIT(ptable_list[1]),
+};
+
+#define PD_PTABLE(page) ((ptable_desc *)&(virt_to_page(page)->lru))
+#define PD_PAGE(ptable) (list_entry(ptable, struct page, lru))
+#define PD_MARKBITS(dp) (*(unsigned int *)&PD_PAGE(dp)->index)
+
+static const int ptable_shift[2] = {
+	7+2, /* PGD, PMD */
+	6+2, /* PTE */
+};
+
+#define ptable_size(type) (1U << ptable_shift[type])
+#define ptable_mask(type) ((1U << (PAGE_SIZE / ptable_size(type))) - 1)
+
+void __init init_pointer_table(void *table, int type)
+{
+	ptable_desc *dp;
+	unsigned long ptable = (unsigned long)table;
+	unsigned long page = ptable & PAGE_MASK;
+	unsigned int mask = 1U << ((ptable - page)/ptable_size(type));
+
+	dp = PD_PTABLE(page);
+	if (!(PD_MARKBITS(dp) & mask)) {
+		PD_MARKBITS(dp) = ptable_mask(type);
+		list_add(dp, &ptable_list[type]);
+	}
+
+	PD_MARKBITS(dp) &= ~mask;
+	pr_debug("init_pointer_table: %lx, %x\n", ptable, PD_MARKBITS(dp));
+
+	/* unreserve the page so it's possible to free that page */
+	__ClearPageReserved(PD_PAGE(dp));
+	init_page_count(PD_PAGE(dp));
+
+	return;
+}
+
+void *get_pointer_table(int type)
+{
+	ptable_desc *dp = ptable_list[type].next;
+	unsigned int mask = list_empty(&ptable_list[type]) ? 0 : PD_MARKBITS(dp);
+	unsigned int tmp, off;
+
+	/*
+	 * For a pointer table for a user process address space, a
+	 * table is taken from a page allocated for the purpose.  Each
+	 * page can hold 8 pointer tables.  The page is remapped in
+	 * virtual address space to be noncacheable.
+	 */
+	if (mask == 0) {
+		void *page;
+		ptable_desc *new;
+
+		if (!(page = (void *)get_zeroed_page(GFP_KERNEL)))
+			return NULL;
+
+		if (type == TABLE_PTE) {
+			/*
+			 * m68k doesn't have SPLIT_PTE_PTLOCKS for not having
+			 * SMP.
+			 */
+			pgtable_pte_page_ctor(virt_to_page(page));
+		}
+
+		mmu_page_ctor(page);
+
+		new = PD_PTABLE(page);
+		PD_MARKBITS(new) = ptable_mask(type) - 1;
+		list_add_tail(new, dp);
+
+		return (pmd_t *)page;
+	}
+
+	for (tmp = 1, off = 0; (mask & tmp) == 0; tmp <<= 1, off += ptable_size(type))
+		;
+	PD_MARKBITS(dp) = mask & ~tmp;
+	if (!PD_MARKBITS(dp)) {
+		/* move to end of list */
+		list_move_tail(dp, &ptable_list[type]);
+	}
+	return page_address(PD_PAGE(dp)) + off;
+}
+
+int free_pointer_table(void *table, int type)
+{
+	ptable_desc *dp;
+	unsigned long ptable = (unsigned long)table;
+	unsigned long page = ptable & PAGE_MASK;
+	unsigned int mask = 1U << ((ptable - page)/ptable_size(type));
+
+	dp = PD_PTABLE(page);
+	if (PD_MARKBITS (dp) & mask)
+		panic ("table already free!");
+
+	PD_MARKBITS (dp) |= mask;
+
+	if (PD_MARKBITS(dp) == ptable_mask(type)) {
+		/* all tables in page are free, free page */
+		list_del(dp);
+		mmu_page_dtor((void *)page);
+		if (type == TABLE_PTE)
+			pgtable_pte_page_dtor(virt_to_page(page));
+		free_page (page);
+		return 1;
+	} else if (ptable_list[type].next != dp) {
+		/*
+		 * move this descriptor to the front of the list, since
+		 * it has one or more free tables.
+		 */
+		list_move(dp, &ptable_list[type]);
+	}
+	return 0;
+}
+
 /* size of memory already mapped in head.S */
 extern __initdata unsigned long m68k_init_mapped_size;
 
 extern unsigned long availmem;
 
+static pte_t *last_pte_table __initdata = NULL;
+
 static pte_t * __init kernel_page_table(void)
 {
-	pte_t *ptablep;
+	pte_t *pte_table = last_pte_table;
 
-	ptablep = (pte_t *)memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
-	if (!ptablep)
+	if (((unsigned long)last_pte_table & ~PAGE_MASK) == 0) {
+		pte_table = (pte_t *)memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
+		if (!pte_table) {
 			panic("%s: Failed to allocate %lu bytes align=%lx\n",
 					__func__, PAGE_SIZE, PAGE_SIZE);
+		}
 
-	clear_page(ptablep);
-	__flush_page_to_ram(ptablep);
-	flush_tlb_kernel_page(ptablep);
-	nocache_page(ptablep);
+		clear_page(pte_table);
+		mmu_page_ctor(pte_table);
 
-	return ptablep;
+		last_pte_table = pte_table;
+	}
+
+	last_pte_table += PTRS_PER_PTE;
+
+	return pte_table;
 }
 
-static pmd_t *last_pgtable __initdata = NULL;
-pmd_t *zero_pgtable __initdata = NULL;
+static pmd_t *last_pmd_table __initdata = NULL;
 
 static pmd_t * __init kernel_ptr_table(void)
 {
-	if (!last_pgtable) {
+	if (!last_pmd_table) {
 		unsigned long pmd, last;
 		int i;
 
@@ -91,33 +242,29 @@ static pmd_t * __init kernel_ptr_table(void)
 				last = pmd;
 		}
 
-		last_pgtable = (pmd_t *)last;
+		last_pmd_table = (pmd_t *)last;
 #ifdef DEBUG
-		printk("kernel_ptr_init: %p\n", last_pgtable);
+		printk("kernel_ptr_init: %p\n", last_pmd_table);
 #endif
 	}
 
-	last_pgtable += PTRS_PER_PMD;
-	if (((unsigned long)last_pgtable & ~PAGE_MASK) == 0) {
-		last_pgtable = (pmd_t *)memblock_alloc_low(PAGE_SIZE,
+	last_pmd_table += PTRS_PER_PMD;
+	if (((unsigned long)last_pmd_table & ~PAGE_MASK) == 0) {
+		last_pmd_table = (pmd_t *)memblock_alloc_low(PAGE_SIZE,
 							   PAGE_SIZE);
-		if (!last_pgtable)
+		if (!last_pmd_table)
 			panic("%s: Failed to allocate %lu bytes align=%lx\n",
 			      __func__, PAGE_SIZE, PAGE_SIZE);
 
-		clear_page(last_pgtable);
-		__flush_page_to_ram(last_pgtable);
-		flush_tlb_kernel_page(last_pgtable);
-		nocache_page(last_pgtable);
+		clear_page(last_pmd_table);
+		mmu_page_ctor(last_pmd_table);
 	}
 
-	return last_pgtable;
+	return last_pmd_table;
 }
 
 static void __init map_node(int node)
 {
-#define PTRTREESIZE (256*1024)
-#define ROOTTREESIZE (32*1024*1024)
 	unsigned long physaddr, virtaddr, size;
 	pgd_t *pgd_dir;
 	p4d_t *p4d_dir;
@@ -135,21 +282,21 @@ static void __init map_node(int node)
 
 	while (size > 0) {
 #ifdef DEBUG
-		if (!(virtaddr & (PTRTREESIZE-1)))
+		if (!(virtaddr & (PMD_SIZE-1)))
 			printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK,
 				virtaddr);
 #endif
 		pgd_dir = pgd_offset_k(virtaddr);
 		if (virtaddr && CPU_IS_020_OR_030) {
-			if (!(virtaddr & (ROOTTREESIZE-1)) &&
-			    size >= ROOTTREESIZE) {
+			if (!(virtaddr & (PGDIR_SIZE-1)) &&
+			    size >= PGDIR_SIZE) {
 #ifdef DEBUG
 				printk ("[very early term]");
 #endif
 				pgd_val(*pgd_dir) = physaddr;
-				size -= ROOTTREESIZE;
-				virtaddr += ROOTTREESIZE;
-				physaddr += ROOTTREESIZE;
+				size -= PGDIR_SIZE;
+				virtaddr += PGDIR_SIZE;
+				physaddr += PGDIR_SIZE;
 				continue;
 			}
 		}
@@ -169,24 +316,23 @@ static void __init map_node(int node)
 #ifdef DEBUG
 				printk ("[early term]");
 #endif
-				pmd_dir->pmd[(virtaddr/PTRTREESIZE) & 15] = physaddr;
-				physaddr += PTRTREESIZE;
+				pmd_val(*pmd_dir) = physaddr;
+				physaddr += PMD_SIZE;
 			} else {
 				int i;
 #ifdef DEBUG
 				printk ("[zero map]");
 #endif
-				zero_pgtable = kernel_ptr_table();
-				pte_dir = (pte_t *)zero_pgtable;
-				pmd_dir->pmd[0] = virt_to_phys(pte_dir) |
-					_PAGE_TABLE | _PAGE_ACCESSED;
+				pte_dir = kernel_page_table();
+				pmd_set(pmd_dir, pte_dir);
+
 				pte_val(*pte_dir++) = 0;
 				physaddr += PAGE_SIZE;
-				for (i = 1; i < 64; physaddr += PAGE_SIZE, i++)
+				for (i = 1; i < PTRS_PER_PTE; physaddr += PAGE_SIZE, i++)
 					pte_val(*pte_dir++) = physaddr;
 			}
-			size -= PTRTREESIZE;
-			virtaddr += PTRTREESIZE;
+			size -= PMD_SIZE;
+			virtaddr += PMD_SIZE;
 		} else {
 			if (!pmd_present(*pmd_dir)) {
 #ifdef DEBUG