arch/microblaze/mm/init.c - arm/linux-arm64-legacy - Git at Google

 /*
  * Copyright (C) 2007-2008 Michal Simek <monstr@monstr.eu>
  * Copyright (C) 2006 Atmark Techno, Inc.
  *
  * This file is subject to the terms and conditions of the GNU General Public
  * License. See the file "COPYING" in the main directory of this archive
  * for more details.
  */

 #include <linux/bootmem.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/memblock.h>
 #include <linux/mm.h> /* mem_init */
 #include <linux/initrd.h>
 #include <linux/pagemap.h>
 #include <linux/pfn.h>
 #include <linux/slab.h>
 #include <linux/swap.h>
 #include <linux/export.h>

 #include <asm/page.h>
 #include <asm/mmu_context.h>
 #include <asm/pgalloc.h>
 #include <asm/sections.h>
 #include <asm/tlb.h>
 #include <asm/fixmap.h>

 /* Use for MMU and noMMU because of PCI generic code */
 int mem_init_done;

 #ifndef CONFIG_MMU
 unsigned int __page_offset;
 EXPORT_SYMBOL(__page_offset);

 #else
 static int init_bootmem_done;
 #endif /* CONFIG_MMU */

 char *klimit = _end;

 /*
  * Initialize the bootmem system and give it all the memory we
  * have available.
  */
 unsigned long memory_start;
 EXPORT_SYMBOL(memory_start);
 unsigned long memory_size;
 EXPORT_SYMBOL(memory_size);
 unsigned long lowmem_size;

 #ifdef CONFIG_HIGHMEM
 pte_t *kmap_pte;
 EXPORT_SYMBOL(kmap_pte);
 pgprot_t kmap_prot;
 EXPORT_SYMBOL(kmap_prot);

 static inline pte_t *virt_to_kpte(unsigned long vaddr)
 {
 	return pte_offset_kernel(pmd_offset(pgd_offset_k(vaddr),
 			vaddr), vaddr);
 }

 static void __init highmem_init(void)
 {
 	pr_debug("%x\n", (u32)PKMAP_BASE);
 	map_page(PKMAP_BASE, 0, 0);	/* XXX gross */
 	pkmap_page_table = virt_to_kpte(PKMAP_BASE);

 	kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
 	kmap_prot = PAGE_KERNEL;
 }

 static void highmem_setup(void)
 {
 	unsigned long pfn;

 	for (pfn = max_low_pfn; pfn < max_pfn; ++pfn) {
 		struct page *page = pfn_to_page(pfn);

 		/* FIXME not sure about */
 		if (!memblock_is_reserved(pfn << PAGE_SHIFT))
 			free_highmem_page(page);
 	}
 }
 #endif /* CONFIG_HIGHMEM */

 /*
  * paging_init() sets up the page tables - in fact we've already done this.
  */
 static void __init paging_init(void)
 {
 	unsigned long zones_size[MAX_NR_ZONES];
 #ifdef CONFIG_MMU
 	int idx;

 	/* Setup fixmaps */
 	for (idx = 0; idx < __end_of_fixed_addresses; idx++)
 		clear_fixmap(idx);
 #endif

 	/* Clean every zones */
 	memset(zones_size, 0, sizeof(zones_size));

 #ifdef CONFIG_HIGHMEM
 	highmem_init();

 	zones_size[ZONE_DMA] = max_low_pfn;
 	zones_size[ZONE_HIGHMEM] = max_pfn;
 #else
 	zones_size[ZONE_DMA] = max_pfn;
 #endif

 	/* We don't have holes in memory map */
 	free_area_init_nodes(zones_size);
 }

 void __init setup_memory(void)
 {
 	unsigned long map_size;
 	struct memblock_region *reg;

 #ifndef CONFIG_MMU
 	u32 kernel_align_start, kernel_align_size;

 	/* Find main memory where is the kernel */
 	for_each_memblock(memory, reg) {
 		memory_start = (u32)reg->base;
 		lowmem_size = reg->size;
 		if ((memory_start <= (u32)_text) &&
 			((u32)_text <= (memory_start + lowmem_size - 1))) {
 			memory_size = lowmem_size;
 			PAGE_OFFSET = memory_start;
 			pr_info("%s: Main mem: 0x%x, size 0x%08x\n",
 				__func__, (u32) memory_start,
 					(u32) memory_size);
 			break;
 		}
 	}

 	if (!memory_start || !memory_size) {
 		panic("%s: Missing memory setting 0x%08x, size=0x%08x\n",
 			__func__, (u32) memory_start, (u32) memory_size);
 	}

 	/* reservation of region where is the kernel */
 	kernel_align_start = PAGE_DOWN((u32)_text);
 	/* ALIGN can be remove because _end in vmlinux.lds.S is align */
 	kernel_align_size = PAGE_UP((u32)klimit) - kernel_align_start;
 	pr_info("%s: kernel addr:0x%08x-0x%08x size=0x%08x\n",
 		__func__, kernel_align_start, kernel_align_start
 			+ kernel_align_size, kernel_align_size);
 	memblock_reserve(kernel_align_start, kernel_align_size);
 #endif
 	/*
 	 * Kernel:
 	 * start: base phys address of kernel - page align
 	 * end: base phys address of kernel - page align
 	 *
 	 * min_low_pfn - the first page (mm/bootmem.c - node_boot_start)
 	 * max_low_pfn
 	 * max_mapnr - the first unused page (mm/bootmem.c - node_low_pfn)
 	 */

 	/* memory start is from the kernel end (aligned) to higher addr */
 	min_low_pfn = memory_start >> PAGE_SHIFT; /* minimum for allocation */
 	/* RAM is assumed contiguous */
 	max_mapnr = memory_size >> PAGE_SHIFT;
 	max_low_pfn = ((u64)memory_start + (u64)lowmem_size) >> PAGE_SHIFT;
 	max_pfn = ((u64)memory_start + (u64)memory_size) >> PAGE_SHIFT;

 	pr_info("%s: max_mapnr: %#lx\n", __func__, max_mapnr);
 	pr_info("%s: min_low_pfn: %#lx\n", __func__, min_low_pfn);
 	pr_info("%s: max_low_pfn: %#lx\n", __func__, max_low_pfn);
 	pr_info("%s: max_pfn: %#lx\n", __func__, max_pfn);

 	/*
 	 * Find an area to use for the bootmem bitmap.
 	 * We look for the first area which is at least
 	 * 128kB in length (128kB is enough for a bitmap
 	 * for 4GB of memory, using 4kB pages), plus 1 page
 	 * (in case the address isn't page-aligned).
 	 */
 	map_size = init_bootmem_node(NODE_DATA(0),
 		PFN_UP(TOPHYS((u32)klimit)), min_low_pfn, max_low_pfn);
 	memblock_reserve(PFN_UP(TOPHYS((u32)klimit)) << PAGE_SHIFT, map_size);

 	/* Add active regions with valid PFNs */
 	for_each_memblock(memory, reg) {
 		unsigned long start_pfn, end_pfn;

 		start_pfn = memblock_region_memory_base_pfn(reg);
 		end_pfn = memblock_region_memory_end_pfn(reg);
 		memblock_set_node(start_pfn << PAGE_SHIFT,
 				  (end_pfn - start_pfn) << PAGE_SHIFT,
 				  &memblock.memory, 0);
 	}

 	/* free bootmem is whole main memory */
 	free_bootmem_with_active_regions(0, max_low_pfn);

 	/* reserve allocate blocks */
 	for_each_memblock(reserved, reg) {
 		unsigned long top = reg->base + reg->size - 1;

 		pr_debug("reserved - 0x%08x-0x%08x, %lx, %lx\n",
 			 (u32) reg->base, (u32) reg->size, top,
 						memory_start + lowmem_size - 1);

 		if (top <= (memory_start + lowmem_size - 1)) {
 			reserve_bootmem(reg->base, reg->size, BOOTMEM_DEFAULT);
 		} else if (reg->base < (memory_start + lowmem_size - 1)) {
 			unsigned long trunc_size = memory_start + lowmem_size -
 								reg->base;
 			reserve_bootmem(reg->base, trunc_size, BOOTMEM_DEFAULT);
 		}
 	}

 	/* XXX need to clip this if using highmem? */
 	sparse_memory_present_with_active_regions(0);

 #ifdef CONFIG_MMU
 	init_bootmem_done = 1;
 #endif
 	paging_init();
 }

 #ifdef CONFIG_BLK_DEV_INITRD
 void free_initrd_mem(unsigned long start, unsigned long end)
 {
 	free_reserved_area((void *)start, (void *)end, -1, "initrd");
 }
 #endif

 void free_initmem(void)
 {
 	free_initmem_default(-1);
 }

 void __init mem_init(void)
 {
 	high_memory = (void *)__va(memory_start + lowmem_size - 1);

 	/* this will put all memory onto the freelists */
 	free_all_bootmem();
 #ifdef CONFIG_HIGHMEM
 	highmem_setup();
 #endif

 	mem_init_print_info(NULL);
 #ifdef CONFIG_MMU
 	pr_info("Kernel virtual memory layout:\n");
 	pr_info("  * 0x%08lx..0x%08lx  : fixmap\n", FIXADDR_START, FIXADDR_TOP);
 #ifdef CONFIG_HIGHMEM
 	pr_info("  * 0x%08lx..0x%08lx  : highmem PTEs\n",
 		PKMAP_BASE, PKMAP_ADDR(LAST_PKMAP));
 #endif /* CONFIG_HIGHMEM */
 	pr_info("  * 0x%08lx..0x%08lx  : early ioremap\n",
 		ioremap_bot, ioremap_base);
 	pr_info("  * 0x%08lx..0x%08lx  : vmalloc & ioremap\n",
 		(unsigned long)VMALLOC_START, VMALLOC_END);
 #endif
 	mem_init_done = 1;
 }

 #ifndef CONFIG_MMU
 int page_is_ram(unsigned long pfn)
 {
 	return __range_ok(pfn, 0);
 }
 #else
 int page_is_ram(unsigned long pfn)
 {
 	return pfn < max_low_pfn;
 }

 /*
  * Check for command-line options that affect what MMU_init will do.
  */
 static void mm_cmdline_setup(void)
 {
 	unsigned long maxmem = 0;
 	char *p = cmd_line;

 	/* Look for mem= option on command line */
 	p = strstr(cmd_line, "mem=");
 	if (p) {
 		p += 4;
 		maxmem = memparse(p, &p);
 		if (maxmem && memory_size > maxmem) {
 			memory_size = maxmem;
 			memblock.memory.regions[0].size = memory_size;
 		}
 	}
 }

 /*
  * MMU_init_hw does the chip-specific initialization of the MMU hardware.
  */
 static void __init mmu_init_hw(void)
 {
 	/*
 	 * The Zone Protection Register (ZPR) defines how protection will
 	 * be applied to every page which is a member of a given zone. At
 	 * present, we utilize only two of the zones.
 	 * The zone index bits (of ZSEL) in the PTE are used for software
 	 * indicators, except the LSB.  For user access, zone 1 is used,
 	 * for kernel access, zone 0 is used.  We set all but zone 1
 	 * to zero, allowing only kernel access as indicated in the PTE.
 	 * For zone 1, we set a 01 binary (a value of 10 will not work)
 	 * to allow user access as indicated in the PTE.  This also allows
 	 * kernel access as indicated in the PTE.
 	 */
 	__asm__ __volatile__ ("ori r11, r0, 0x10000000;" \
 			"mts rzpr, r11;"
 			: : : "r11");
 }

 /*
  * MMU_init sets up the basic memory mappings for the kernel,
  * including both RAM and possibly some I/O regions,
  * and sets up the page tables and the MMU hardware ready to go.
  */

 /* called from head.S */
 asmlinkage void __init mmu_init(void)
 {
 	unsigned int kstart, ksize;

 	if (!memblock.reserved.cnt) {
 		pr_emerg("Error memory count\n");
 		machine_restart(NULL);
 	}

 	if ((u32) memblock.memory.regions[0].size < 0x400000) {
 		pr_emerg("Memory must be greater than 4MB\n");
 		machine_restart(NULL);
 	}

 	if ((u32) memblock.memory.regions[0].size < kernel_tlb) {
 		pr_emerg("Kernel size is greater than memory node\n");
 		machine_restart(NULL);
 	}

 	/* Find main memory where the kernel is */
 	memory_start = (u32) memblock.memory.regions[0].base;
 	lowmem_size = memory_size = (u32) memblock.memory.regions[0].size;

 	if (lowmem_size > CONFIG_LOWMEM_SIZE) {
 		lowmem_size = CONFIG_LOWMEM_SIZE;
 #ifndef CONFIG_HIGHMEM
 		memory_size = lowmem_size;
 #endif
 	}

 	mm_cmdline_setup(); /* FIXME parse args from command line - not used */

 	/*
 	 * Map out the kernel text/data/bss from the available physical
 	 * memory.
 	 */
 	kstart = __pa(CONFIG_KERNEL_START); /* kernel start */
 	/* kernel size */
 	ksize = PAGE_ALIGN(((u32)_end - (u32)CONFIG_KERNEL_START));
 	memblock_reserve(kstart, ksize);

 #if defined(CONFIG_BLK_DEV_INITRD)
 	/* Remove the init RAM disk from the available memory. */
 	if (initrd_start) {
 		unsigned long size;
 		size = initrd_end - initrd_start;
 		memblock_reserve(__virt_to_phys(initrd_start), size);
 	}
 #endif /* CONFIG_BLK_DEV_INITRD */

 	/* Initialize the MMU hardware */
 	mmu_init_hw();

 	/* Map in all of RAM starting at CONFIG_KERNEL_START */
 	mapin_ram();

 	/* Extend vmalloc and ioremap area as big as possible */
 #ifdef CONFIG_HIGHMEM
 	ioremap_base = ioremap_bot = PKMAP_BASE;
 #else
 	ioremap_base = ioremap_bot = FIXADDR_START;
 #endif

 	/* Initialize the context management stuff */
 	mmu_context_init();

 	/* Shortly after that, the entire linear mapping will be available */
 	/* This will also cause that unflatten device tree will be allocated
 	 * inside 768MB limit */
 	memblock_set_current_limit(memory_start + lowmem_size - 1);
 }

 /* This is only called until mem_init is done. */
 void __init *early_get_page(void)
 {
 	void *p;
 	if (init_bootmem_done) {
 		p = alloc_bootmem_pages(PAGE_SIZE);
 	} else {
 		/*
 		 * Mem start + kernel_tlb -> here is limit
 		 * because of mem mapping from head.S
 		 */
 		p = __va(memblock_alloc_base(PAGE_SIZE, PAGE_SIZE,
 					memory_start + kernel_tlb));
 	}
 	return p;
 }

 #endif /* CONFIG_MMU */

 void * __init_refok alloc_maybe_bootmem(size_t size, gfp_t mask)
 {
 	if (mem_init_done)
 		return kmalloc(size, mask);
 	else
 		return alloc_bootmem(size);
 }

 void * __init_refok zalloc_maybe_bootmem(size_t size, gfp_t mask)
 {
 	void *p;

 	if (mem_init_done)
 		p = kzalloc(size, mask);
 	else {
 		p = alloc_bootmem(size);
 		if (p)
 			memset(p, 0, size);
 	}
 	return p;
 }
	/*
	* Copyright (C) 2007-2008 Michal Simek <monstr@monstr.eu>
	* Copyright (C) 2006 Atmark Techno, Inc.
	*
	* This file is subject to the terms and conditions of the GNU General Public
	* License. See the file "COPYING" in the main directory of this archive
	* for more details.
	*/

	#include <linux/bootmem.h>
	#include <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/memblock.h>
	#include <linux/mm.h> /* mem_init */
	#include <linux/initrd.h>
	#include <linux/pagemap.h>
	#include <linux/pfn.h>
	#include <linux/slab.h>
	#include <linux/swap.h>
	#include <linux/export.h>

	#include <asm/page.h>
	#include <asm/mmu_context.h>
	#include <asm/pgalloc.h>
	#include <asm/sections.h>
	#include <asm/tlb.h>
	#include <asm/fixmap.h>

	/* Use for MMU and noMMU because of PCI generic code */
	int mem_init_done;

	#ifndef CONFIG_MMU
	unsigned int __page_offset;
	EXPORT_SYMBOL(__page_offset);

	#else
	static int init_bootmem_done;
	#endif /* CONFIG_MMU */

	char *klimit = _end;

	/*
	* Initialize the bootmem system and give it all the memory we
	* have available.
	*/
	unsigned long memory_start;
	EXPORT_SYMBOL(memory_start);
	unsigned long memory_size;
	EXPORT_SYMBOL(memory_size);
	unsigned long lowmem_size;

	#ifdef CONFIG_HIGHMEM
	pte_t *kmap_pte;
	EXPORT_SYMBOL(kmap_pte);
	pgprot_t kmap_prot;
	EXPORT_SYMBOL(kmap_prot);

	static inline pte_t *virt_to_kpte(unsigned long vaddr)
	{
	return pte_offset_kernel(pmd_offset(pgd_offset_k(vaddr),
	vaddr), vaddr);
	}

	static void __init highmem_init(void)
	{
	pr_debug("%x\n", (u32)PKMAP_BASE);
	map_page(PKMAP_BASE, 0, 0); /* XXX gross */
	pkmap_page_table = virt_to_kpte(PKMAP_BASE);

	kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
	kmap_prot = PAGE_KERNEL;
	}

	static void highmem_setup(void)
	{
	unsigned long pfn;

	for (pfn = max_low_pfn; pfn < max_pfn; ++pfn) {
	struct page *page = pfn_to_page(pfn);

	/* FIXME not sure about */
	if (!memblock_is_reserved(pfn << PAGE_SHIFT))
	free_highmem_page(page);
	}
	}
	#endif /* CONFIG_HIGHMEM */

	/*
	* paging_init() sets up the page tables - in fact we've already done this.
	*/
	static void __init paging_init(void)
	{
	unsigned long zones_size[MAX_NR_ZONES];
	#ifdef CONFIG_MMU
	int idx;

	/* Setup fixmaps */
	for (idx = 0; idx < __end_of_fixed_addresses; idx++)
	clear_fixmap(idx);
	#endif

	/* Clean every zones */
	memset(zones_size, 0, sizeof(zones_size));

	#ifdef CONFIG_HIGHMEM
	highmem_init();

	zones_size[ZONE_DMA] = max_low_pfn;
	zones_size[ZONE_HIGHMEM] = max_pfn;
	#else
	zones_size[ZONE_DMA] = max_pfn;
	#endif

	/* We don't have holes in memory map */
	free_area_init_nodes(zones_size);
	}

	void __init setup_memory(void)
	{
	unsigned long map_size;
	struct memblock_region *reg;

	#ifndef CONFIG_MMU
	u32 kernel_align_start, kernel_align_size;

	/* Find main memory where is the kernel */
	for_each_memblock(memory, reg) {
	memory_start = (u32)reg->base;
	lowmem_size = reg->size;
	if ((memory_start <= (u32)_text) &&
	((u32)_text <= (memory_start + lowmem_size - 1))) {
	memory_size = lowmem_size;
	PAGE_OFFSET = memory_start;
	pr_info("%s: Main mem: 0x%x, size 0x%08x\n",
	__func__, (u32) memory_start,
	(u32) memory_size);
	break;
	}
	}

	if (!memory_start \|\| !memory_size) {
	panic("%s: Missing memory setting 0x%08x, size=0x%08x\n",
	__func__, (u32) memory_start, (u32) memory_size);
	}

	/* reservation of region where is the kernel */
	kernel_align_start = PAGE_DOWN((u32)_text);
	/* ALIGN can be remove because _end in vmlinux.lds.S is align */
	kernel_align_size = PAGE_UP((u32)klimit) - kernel_align_start;
	pr_info("%s: kernel addr:0x%08x-0x%08x size=0x%08x\n",
	__func__, kernel_align_start, kernel_align_start
	+ kernel_align_size, kernel_align_size);
	memblock_reserve(kernel_align_start, kernel_align_size);
	#endif
	/*
	* Kernel:
	* start: base phys address of kernel - page align
	* end: base phys address of kernel - page align
	*
	* min_low_pfn - the first page (mm/bootmem.c - node_boot_start)
	* max_low_pfn
	* max_mapnr - the first unused page (mm/bootmem.c - node_low_pfn)
	*/

	/* memory start is from the kernel end (aligned) to higher addr */
	min_low_pfn = memory_start >> PAGE_SHIFT; /* minimum for allocation */
	/* RAM is assumed contiguous */
	max_mapnr = memory_size >> PAGE_SHIFT;
	max_low_pfn = ((u64)memory_start + (u64)lowmem_size) >> PAGE_SHIFT;
	max_pfn = ((u64)memory_start + (u64)memory_size) >> PAGE_SHIFT;

	pr_info("%s: max_mapnr: %#lx\n", __func__, max_mapnr);
	pr_info("%s: min_low_pfn: %#lx\n", __func__, min_low_pfn);
	pr_info("%s: max_low_pfn: %#lx\n", __func__, max_low_pfn);
	pr_info("%s: max_pfn: %#lx\n", __func__, max_pfn);

	/*
	* Find an area to use for the bootmem bitmap.
	* We look for the first area which is at least
	* 128kB in length (128kB is enough for a bitmap
	* for 4GB of memory, using 4kB pages), plus 1 page
	* (in case the address isn't page-aligned).
	*/
	map_size = init_bootmem_node(NODE_DATA(0),
	PFN_UP(TOPHYS((u32)klimit)), min_low_pfn, max_low_pfn);
	memblock_reserve(PFN_UP(TOPHYS((u32)klimit)) << PAGE_SHIFT, map_size);

	/* Add active regions with valid PFNs */
	for_each_memblock(memory, reg) {
	unsigned long start_pfn, end_pfn;

	start_pfn = memblock_region_memory_base_pfn(reg);
	end_pfn = memblock_region_memory_end_pfn(reg);
	memblock_set_node(start_pfn << PAGE_SHIFT,
	(end_pfn - start_pfn) << PAGE_SHIFT,
	&memblock.memory, 0);
	}

	/* free bootmem is whole main memory */
	free_bootmem_with_active_regions(0, max_low_pfn);

	/* reserve allocate blocks */
	for_each_memblock(reserved, reg) {
	unsigned long top = reg->base + reg->size - 1;

	pr_debug("reserved - 0x%08x-0x%08x, %lx, %lx\n",
	(u32) reg->base, (u32) reg->size, top,
	memory_start + lowmem_size - 1);

	if (top <= (memory_start + lowmem_size - 1)) {
	reserve_bootmem(reg->base, reg->size, BOOTMEM_DEFAULT);
	} else if (reg->base < (memory_start + lowmem_size - 1)) {
	unsigned long trunc_size = memory_start + lowmem_size -
	reg->base;
	reserve_bootmem(reg->base, trunc_size, BOOTMEM_DEFAULT);
	}
	}

	/* XXX need to clip this if using highmem? */
	sparse_memory_present_with_active_regions(0);

	#ifdef CONFIG_MMU
	init_bootmem_done = 1;
	#endif
	paging_init();
	}

	#ifdef CONFIG_BLK_DEV_INITRD
	void free_initrd_mem(unsigned long start, unsigned long end)
	{
	free_reserved_area((void )start, (void )end, -1, "initrd");
	}
	#endif

	void free_initmem(void)
	{
	free_initmem_default(-1);
	}

	void __init mem_init(void)
	{
	high_memory = (void *)__va(memory_start + lowmem_size - 1);

	/* this will put all memory onto the freelists */
	free_all_bootmem();
	#ifdef CONFIG_HIGHMEM
	highmem_setup();
	#endif

	mem_init_print_info(NULL);
	#ifdef CONFIG_MMU
	pr_info("Kernel virtual memory layout:\n");
	pr_info(" * 0x%08lx..0x%08lx : fixmap\n", FIXADDR_START, FIXADDR_TOP);
	#ifdef CONFIG_HIGHMEM
	pr_info(" * 0x%08lx..0x%08lx : highmem PTEs\n",
	PKMAP_BASE, PKMAP_ADDR(LAST_PKMAP));
	#endif /* CONFIG_HIGHMEM */
	pr_info(" * 0x%08lx..0x%08lx : early ioremap\n",
	ioremap_bot, ioremap_base);
	pr_info(" * 0x%08lx..0x%08lx : vmalloc & ioremap\n",
	(unsigned long)VMALLOC_START, VMALLOC_END);
	#endif
	mem_init_done = 1;
	}

	#ifndef CONFIG_MMU
	int page_is_ram(unsigned long pfn)
	{
	return __range_ok(pfn, 0);
	}
	#else
	int page_is_ram(unsigned long pfn)
	{
	return pfn < max_low_pfn;
	}

	/*
	* Check for command-line options that affect what MMU_init will do.
	*/
	static void mm_cmdline_setup(void)
	{
	unsigned long maxmem = 0;
	char *p = cmd_line;

	/* Look for mem= option on command line */
	p = strstr(cmd_line, "mem=");
	if (p) {
	p += 4;
	maxmem = memparse(p, &p);
	if (maxmem && memory_size > maxmem) {
	memory_size = maxmem;
	memblock.memory.regions[0].size = memory_size;
	}
	}
	}

	/*
	* MMU_init_hw does the chip-specific initialization of the MMU hardware.
	*/
	static void __init mmu_init_hw(void)
	{
	/*
	* The Zone Protection Register (ZPR) defines how protection will
	* be applied to every page which is a member of a given zone. At
	* present, we utilize only two of the zones.
	* The zone index bits (of ZSEL) in the PTE are used for software
	* indicators, except the LSB. For user access, zone 1 is used,
	* for kernel access, zone 0 is used. We set all but zone 1
	* to zero, allowing only kernel access as indicated in the PTE.
	* For zone 1, we set a 01 binary (a value of 10 will not work)
	* to allow user access as indicated in the PTE. This also allows
	* kernel access as indicated in the PTE.
	*/
	__asm__ __volatile__ ("ori r11, r0, 0x10000000;" \
	"mts rzpr, r11;"
	: : : "r11");
	}

	/*
	* MMU_init sets up the basic memory mappings for the kernel,
	* including both RAM and possibly some I/O regions,
	* and sets up the page tables and the MMU hardware ready to go.
	*/

	/* called from head.S */
	asmlinkage void __init mmu_init(void)
	{
	unsigned int kstart, ksize;

	if (!memblock.reserved.cnt) {
	pr_emerg("Error memory count\n");
	machine_restart(NULL);
	}

	if ((u32) memblock.memory.regions[0].size < 0x400000) {
	pr_emerg("Memory must be greater than 4MB\n");
	machine_restart(NULL);
	}

	if ((u32) memblock.memory.regions[0].size < kernel_tlb) {
	pr_emerg("Kernel size is greater than memory node\n");
	machine_restart(NULL);
	}

	/* Find main memory where the kernel is */
	memory_start = (u32) memblock.memory.regions[0].base;
	lowmem_size = memory_size = (u32) memblock.memory.regions[0].size;

	if (lowmem_size > CONFIG_LOWMEM_SIZE) {
	lowmem_size = CONFIG_LOWMEM_SIZE;
	#ifndef CONFIG_HIGHMEM
	memory_size = lowmem_size;
	#endif
	}

	mm_cmdline_setup(); /* FIXME parse args from command line - not used */

	/*
	* Map out the kernel text/data/bss from the available physical
	* memory.
	*/
	kstart = __pa(CONFIG_KERNEL_START); /* kernel start */
	/* kernel size */
	ksize = PAGE_ALIGN(((u32)_end - (u32)CONFIG_KERNEL_START));
	memblock_reserve(kstart, ksize);

	#if defined(CONFIG_BLK_DEV_INITRD)
	/* Remove the init RAM disk from the available memory. */
	if (initrd_start) {
	unsigned long size;
	size = initrd_end - initrd_start;
	memblock_reserve(__virt_to_phys(initrd_start), size);
	}
	#endif /* CONFIG_BLK_DEV_INITRD */

	/* Initialize the MMU hardware */
	mmu_init_hw();

	/* Map in all of RAM starting at CONFIG_KERNEL_START */
	mapin_ram();

	/* Extend vmalloc and ioremap area as big as possible */
	#ifdef CONFIG_HIGHMEM
	ioremap_base = ioremap_bot = PKMAP_BASE;
	#else
	ioremap_base = ioremap_bot = FIXADDR_START;
	#endif

	/* Initialize the context management stuff */
	mmu_context_init();

	/* Shortly after that, the entire linear mapping will be available */
	/* This will also cause that unflatten device tree will be allocated
	* inside 768MB limit */
	memblock_set_current_limit(memory_start + lowmem_size - 1);
	}

	/* This is only called until mem_init is done. */
	void __init *early_get_page(void)
	{
	void *p;
	if (init_bootmem_done) {
	p = alloc_bootmem_pages(PAGE_SIZE);
	} else {
	/*
	* Mem start + kernel_tlb -> here is limit
	* because of mem mapping from head.S
	*/
	p = __va(memblock_alloc_base(PAGE_SIZE, PAGE_SIZE,
	memory_start + kernel_tlb));
	}
	return p;
	}

	#endif /* CONFIG_MMU */

	void * __init_refok alloc_maybe_bootmem(size_t size, gfp_t mask)
	{
	if (mem_init_done)
	return kmalloc(size, mask);
	else
	return alloc_bootmem(size);
	}

	void * __init_refok zalloc_maybe_bootmem(size_t size, gfp_t mask)
	{
	void *p;

	if (mem_init_done)
	p = kzalloc(size, mask);
	else {
	p = alloc_bootmem(size);
	if (p)
	memset(p, 0, size);
	}
	return p;
	}