arch/sparc/mm/init_32.c - kernel/msm-4.9 - Gitiles

 /*
  *  linux/arch/sparc/mm/init.c
  *
  *  Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
  *  Copyright (C) 1995 Eddie C. Dost (ecd@skynet.be)
  *  Copyright (C) 1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
  *  Copyright (C) 2000 Anton Blanchard (anton@samba.org)
  */

 #include <linux/module.h>
 #include <linux/signal.h>
 #include <linux/sched.h>
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/string.h>
 #include <linux/types.h>
 #include <linux/ptrace.h>
 #include <linux/mman.h>
 #include <linux/mm.h>
 #include <linux/swap.h>
 #include <linux/initrd.h>
 #include <linux/init.h>
 #include <linux/highmem.h>
 #include <linux/bootmem.h>
 #include <linux/pagemap.h>
 #include <linux/poison.h>
 #include <linux/gfp.h>

 #include <asm/sections.h>
 #include <asm/page.h>
 #include <asm/pgtable.h>
 #include <asm/vaddrs.h>
 #include <asm/pgalloc.h>	/* bug in asm-generic/tlb.h: check_pgt_cache */
 #include <asm/tlb.h>
 #include <asm/prom.h>
 #include <asm/leon.h>

 unsigned long *sparc_valid_addr_bitmap;
 EXPORT_SYMBOL(sparc_valid_addr_bitmap);

 unsigned long phys_base;
 EXPORT_SYMBOL(phys_base);

 unsigned long pfn_base;
 EXPORT_SYMBOL(pfn_base);

 struct sparc_phys_banks sp_banks[SPARC_PHYS_BANKS+1];

 /* Initial ramdisk setup */
 extern unsigned int sparc_ramdisk_image;
 extern unsigned int sparc_ramdisk_size;

 unsigned long highstart_pfn, highend_pfn;

 void show_mem(unsigned int filter)
 {
 	printk("Mem-info:\n");
 	show_free_areas(filter);
 	printk("Free swap:       %6ldkB\n",
 	       nr_swap_pages << (PAGE_SHIFT-10));
 	printk("%ld pages of RAM\n", totalram_pages);
 	printk("%ld free pages\n", nr_free_pages());
 }


 extern unsigned long cmdline_memory_size;
 unsigned long last_valid_pfn;

 unsigned long calc_highpages(void)
 {
 	int i;
 	int nr = 0;

 	for (i = 0; sp_banks[i].num_bytes != 0; i++) {
 		unsigned long start_pfn = sp_banks[i].base_addr >> PAGE_SHIFT;
 		unsigned long end_pfn = (sp_banks[i].base_addr + sp_banks[i].num_bytes) >> PAGE_SHIFT;

 		if (end_pfn <= max_low_pfn)
 			continue;

 		if (start_pfn < max_low_pfn)
 			start_pfn = max_low_pfn;

 		nr += end_pfn - start_pfn;
 	}

 	return nr;
 }

 static unsigned long calc_max_low_pfn(void)
 {
 	int i;
 	unsigned long tmp = pfn_base + (SRMMU_MAXMEM >> PAGE_SHIFT);
 	unsigned long curr_pfn, last_pfn;

 	last_pfn = (sp_banks[0].base_addr + sp_banks[0].num_bytes) >> PAGE_SHIFT;
 	for (i = 1; sp_banks[i].num_bytes != 0; i++) {
 		curr_pfn = sp_banks[i].base_addr >> PAGE_SHIFT;

 		if (curr_pfn >= tmp) {
 			if (last_pfn < tmp)
 				tmp = last_pfn;
 			break;
 		}

 		last_pfn = (sp_banks[i].base_addr + sp_banks[i].num_bytes) >> PAGE_SHIFT;
 	}

 	return tmp;
 }

 unsigned long __init bootmem_init(unsigned long *pages_avail)
 {
 	unsigned long bootmap_size, start_pfn;
 	unsigned long end_of_phys_memory = 0UL;
 	unsigned long bootmap_pfn, bytes_avail, size;
 	int i;

 	bytes_avail = 0UL;
 	for (i = 0; sp_banks[i].num_bytes != 0; i++) {
 		end_of_phys_memory = sp_banks[i].base_addr +
 			sp_banks[i].num_bytes;
 		bytes_avail += sp_banks[i].num_bytes;
 		if (cmdline_memory_size) {
 			if (bytes_avail > cmdline_memory_size) {
 				unsigned long slack = bytes_avail - cmdline_memory_size;

 				bytes_avail -= slack;
 				end_of_phys_memory -= slack;

 				sp_banks[i].num_bytes -= slack;
 				if (sp_banks[i].num_bytes == 0) {
 					sp_banks[i].base_addr = 0xdeadbeef;
 				} else {
 					sp_banks[i+1].num_bytes = 0;
 					sp_banks[i+1].base_addr = 0xdeadbeef;
 				}
 				break;
 			}
 		}
 	}

 	/* Start with page aligned address of last symbol in kernel
 	 * image.
 	 */
 	start_pfn  = (unsigned long)__pa(PAGE_ALIGN((unsigned long) &_end));

 	/* Now shift down to get the real physical page frame number. */
 	start_pfn >>= PAGE_SHIFT;

 	bootmap_pfn = start_pfn;

 	max_pfn = end_of_phys_memory >> PAGE_SHIFT;

 	max_low_pfn = max_pfn;
 	highstart_pfn = highend_pfn = max_pfn;

 	if (max_low_pfn > pfn_base + (SRMMU_MAXMEM >> PAGE_SHIFT)) {
 		highstart_pfn = pfn_base + (SRMMU_MAXMEM >> PAGE_SHIFT);
 		max_low_pfn = calc_max_low_pfn();
 		printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
 		    calc_highpages() >> (20 - PAGE_SHIFT));
 	}

 #ifdef CONFIG_BLK_DEV_INITRD
 	/* Now have to check initial ramdisk, so that bootmap does not overwrite it */
 	if (sparc_ramdisk_image) {
 		if (sparc_ramdisk_image >= (unsigned long)&_end - 2 * PAGE_SIZE)
 			sparc_ramdisk_image -= KERNBASE;
 		initrd_start = sparc_ramdisk_image + phys_base;
 		initrd_end = initrd_start + sparc_ramdisk_size;
 		if (initrd_end > end_of_phys_memory) {
 			printk(KERN_CRIT "initrd extends beyond end of memory "
 		                 	 "(0x%016lx > 0x%016lx)\ndisabling initrd\n",
 			       initrd_end, end_of_phys_memory);
 			initrd_start = 0;
 		}
 		if (initrd_start) {
 			if (initrd_start >= (start_pfn << PAGE_SHIFT) &&
 			    initrd_start < (start_pfn << PAGE_SHIFT) + 2 * PAGE_SIZE)
 				bootmap_pfn = PAGE_ALIGN (initrd_end) >> PAGE_SHIFT;
 		}
 	}
 #endif
 	/* Initialize the boot-time allocator. */
 	bootmap_size = init_bootmem_node(NODE_DATA(0), bootmap_pfn, pfn_base,
 					 max_low_pfn);

 	/* Now register the available physical memory with the
 	 * allocator.
 	 */
 	*pages_avail = 0;
 	for (i = 0; sp_banks[i].num_bytes != 0; i++) {
 		unsigned long curr_pfn, last_pfn;

 		curr_pfn = sp_banks[i].base_addr >> PAGE_SHIFT;
 		if (curr_pfn >= max_low_pfn)
 			break;

 		last_pfn = (sp_banks[i].base_addr + sp_banks[i].num_bytes) >> PAGE_SHIFT;
 		if (last_pfn > max_low_pfn)
 			last_pfn = max_low_pfn;

 		/*
 		 * .. finally, did all the rounding and playing
 		 * around just make the area go away?
 		 */
 		if (last_pfn <= curr_pfn)
 			continue;

 		size = (last_pfn - curr_pfn) << PAGE_SHIFT;
 		*pages_avail += last_pfn - curr_pfn;

 		free_bootmem(sp_banks[i].base_addr, size);
 	}

 #ifdef CONFIG_BLK_DEV_INITRD
 	if (initrd_start) {
 		/* Reserve the initrd image area. */
 		size = initrd_end - initrd_start;
 		reserve_bootmem(initrd_start, size, BOOTMEM_DEFAULT);
 		*pages_avail -= PAGE_ALIGN(size) >> PAGE_SHIFT;

 		initrd_start = (initrd_start - phys_base) + PAGE_OFFSET;
 		initrd_end = (initrd_end - phys_base) + PAGE_OFFSET;
 	}
 #endif
 	/* Reserve the kernel text/data/bss. */
 	size = (start_pfn << PAGE_SHIFT) - phys_base;
 	reserve_bootmem(phys_base, size, BOOTMEM_DEFAULT);
 	*pages_avail -= PAGE_ALIGN(size) >> PAGE_SHIFT;

 	/* Reserve the bootmem map.   We do not account for it
 	 * in pages_avail because we will release that memory
 	 * in free_all_bootmem.
 	 */
 	size = bootmap_size;
 	reserve_bootmem((bootmap_pfn << PAGE_SHIFT), size, BOOTMEM_DEFAULT);
 	*pages_avail -= PAGE_ALIGN(size) >> PAGE_SHIFT;

 	return max_pfn;
 }

 /*
  * paging_init() sets up the page tables: We call the MMU specific
  * init routine based upon the Sun model type on the Sparc.
  *
  */
 extern void srmmu_paging_init(void);
 extern void device_scan(void);

 void __init paging_init(void)
 {
 	srmmu_paging_init();
 	prom_build_devicetree();
 	of_fill_in_cpu_data();
 	device_scan();
 }

 static void __init taint_real_pages(void)
 {
 	int i;

 	for (i = 0; sp_banks[i].num_bytes; i++) {
 		unsigned long start, end;

 		start = sp_banks[i].base_addr;
 		end = start + sp_banks[i].num_bytes;

 		while (start < end) {
 			set_bit(start >> 20, sparc_valid_addr_bitmap);
 			start += PAGE_SIZE;
 		}
 	}
 }

 static void map_high_region(unsigned long start_pfn, unsigned long end_pfn)
 {
 	unsigned long tmp;

 #ifdef CONFIG_DEBUG_HIGHMEM
 	printk("mapping high region %08lx - %08lx\n", start_pfn, end_pfn);
 #endif

 	for (tmp = start_pfn; tmp < end_pfn; tmp++) {
 		struct page *page = pfn_to_page(tmp);

 		ClearPageReserved(page);
 		init_page_count(page);
 		__free_page(page);
 		totalhigh_pages++;
 	}
 }

 void __init mem_init(void)
 {
 	int codepages = 0;
 	int datapages = 0;
 	int initpages = 0;
 	int reservedpages = 0;
 	int i;

 	if (PKMAP_BASE+LAST_PKMAP*PAGE_SIZE >= FIXADDR_START) {
 		prom_printf("BUG: fixmap and pkmap areas overlap\n");
 		prom_printf("pkbase: 0x%lx pkend: 0x%lx fixstart 0x%lx\n",
 		       PKMAP_BASE,
 		       (unsigned long)PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
 		       FIXADDR_START);
 		prom_printf("Please mail sparclinux@vger.kernel.org.\n");
 		prom_halt();
 	}


 	/* Saves us work later. */
 	memset((void *)&empty_zero_page, 0, PAGE_SIZE);

 	i = last_valid_pfn >> ((20 - PAGE_SHIFT) + 5);
 	i += 1;
 	sparc_valid_addr_bitmap = (unsigned long *)
 		__alloc_bootmem(i << 2, SMP_CACHE_BYTES, 0UL);

 	if (sparc_valid_addr_bitmap == NULL) {
 		prom_printf("mem_init: Cannot alloc valid_addr_bitmap.\n");
 		prom_halt();
 	}
 	memset(sparc_valid_addr_bitmap, 0, i << 2);

 	taint_real_pages();

 	max_mapnr = last_valid_pfn - pfn_base;
 	high_memory = __va(max_low_pfn << PAGE_SHIFT);

 	totalram_pages = free_all_bootmem();

 	for (i = 0; sp_banks[i].num_bytes != 0; i++) {
 		unsigned long start_pfn = sp_banks[i].base_addr >> PAGE_SHIFT;
 		unsigned long end_pfn = (sp_banks[i].base_addr + sp_banks[i].num_bytes) >> PAGE_SHIFT;

 		num_physpages += sp_banks[i].num_bytes >> PAGE_SHIFT;

 		if (end_pfn <= highstart_pfn)
 			continue;

 		if (start_pfn < highstart_pfn)
 			start_pfn = highstart_pfn;

 		map_high_region(start_pfn, end_pfn);
 	}

 	totalram_pages += totalhigh_pages;

 	codepages = (((unsigned long) &_etext) - ((unsigned long)&_start));
 	codepages = PAGE_ALIGN(codepages) >> PAGE_SHIFT;
 	datapages = (((unsigned long) &_edata) - ((unsigned long)&_etext));
 	datapages = PAGE_ALIGN(datapages) >> PAGE_SHIFT;
 	initpages = (((unsigned long) &__init_end) - ((unsigned long) &__init_begin));
 	initpages = PAGE_ALIGN(initpages) >> PAGE_SHIFT;

 	/* Ignore memory holes for the purpose of counting reserved pages */
 	for (i=0; i < max_low_pfn; i++)
 		if (test_bit(i >> (20 - PAGE_SHIFT), sparc_valid_addr_bitmap)
 		    && PageReserved(pfn_to_page(i)))
 			reservedpages++;

 	printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init, %ldk highmem)\n",
 	       nr_free_pages() << (PAGE_SHIFT-10),
 	       num_physpages << (PAGE_SHIFT - 10),
 	       codepages << (PAGE_SHIFT-10),
 	       reservedpages << (PAGE_SHIFT - 10),
 	       datapages << (PAGE_SHIFT-10),
 	       initpages << (PAGE_SHIFT-10),
 	       totalhigh_pages << (PAGE_SHIFT-10));
 }

 void free_initmem (void)
 {
 	unsigned long addr;
 	unsigned long freed;

 	addr = (unsigned long)(&__init_begin);
 	freed = (unsigned long)(&__init_end) - addr;
 	for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
 		struct page *p;

 		memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
 		p = virt_to_page(addr);

 		ClearPageReserved(p);
 		init_page_count(p);
 		__free_page(p);
 		totalram_pages++;
 		num_physpages++;
 	}
 	printk(KERN_INFO "Freeing unused kernel memory: %ldk freed\n",
 		freed >> 10);
 }

 #ifdef CONFIG_BLK_DEV_INITRD
 void free_initrd_mem(unsigned long start, unsigned long end)
 {
 	if (start < end)
 		printk(KERN_INFO "Freeing initrd memory: %ldk freed\n",
 			(end - start) >> 10);
 	for (; start < end; start += PAGE_SIZE) {
 		struct page *p;

 		memset((void *)start, POISON_FREE_INITMEM, PAGE_SIZE);
 		p = virt_to_page(start);

 		ClearPageReserved(p);
 		init_page_count(p);
 		__free_page(p);
 		totalram_pages++;
 		num_physpages++;
 	}
 }
 #endif

 void sparc_flush_page_to_ram(struct page *page)
 {
 	unsigned long vaddr = (unsigned long)page_address(page);

 	if (vaddr)
 		__flush_page_to_ram(vaddr);
 }
 EXPORT_SYMBOL(sparc_flush_page_to_ram);
	/*
	* linux/arch/sparc/mm/init.c
	*
	* Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
	* Copyright (C) 1995 Eddie C. Dost (ecd@skynet.be)
	* Copyright (C) 1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
	* Copyright (C) 2000 Anton Blanchard (anton@samba.org)
	*/

	#include <linux/module.h>
	#include <linux/signal.h>
	#include <linux/sched.h>
	#include <linux/kernel.h>
	#include <linux/errno.h>
	#include <linux/string.h>
	#include <linux/types.h>
	#include <linux/ptrace.h>
	#include <linux/mman.h>
	#include <linux/mm.h>
	#include <linux/swap.h>
	#include <linux/initrd.h>
	#include <linux/init.h>
	#include <linux/highmem.h>
	#include <linux/bootmem.h>
	#include <linux/pagemap.h>
	#include <linux/poison.h>
	#include <linux/gfp.h>

	#include <asm/sections.h>
	#include <asm/page.h>
	#include <asm/pgtable.h>
	#include <asm/vaddrs.h>
	#include <asm/pgalloc.h> /* bug in asm-generic/tlb.h: check_pgt_cache */
	#include <asm/tlb.h>
	#include <asm/prom.h>
	#include <asm/leon.h>

	unsigned long *sparc_valid_addr_bitmap;
	EXPORT_SYMBOL(sparc_valid_addr_bitmap);

	unsigned long phys_base;
	EXPORT_SYMBOL(phys_base);

	unsigned long pfn_base;
	EXPORT_SYMBOL(pfn_base);

	struct sparc_phys_banks sp_banks[SPARC_PHYS_BANKS+1];

	/* Initial ramdisk setup */
	extern unsigned int sparc_ramdisk_image;
	extern unsigned int sparc_ramdisk_size;

	unsigned long highstart_pfn, highend_pfn;

	void show_mem(unsigned int filter)
	{
	printk("Mem-info:\n");
	show_free_areas(filter);
	printk("Free swap: %6ldkB\n",
	nr_swap_pages << (PAGE_SHIFT-10));
	printk("%ld pages of RAM\n", totalram_pages);
	printk("%ld free pages\n", nr_free_pages());
	}


	extern unsigned long cmdline_memory_size;
	unsigned long last_valid_pfn;

	unsigned long calc_highpages(void)
	{
	int i;
	int nr = 0;

	for (i = 0; sp_banks[i].num_bytes != 0; i++) {
	unsigned long start_pfn = sp_banks[i].base_addr >> PAGE_SHIFT;
	unsigned long end_pfn = (sp_banks[i].base_addr + sp_banks[i].num_bytes) >> PAGE_SHIFT;

	if (end_pfn <= max_low_pfn)
	continue;

	if (start_pfn < max_low_pfn)
	start_pfn = max_low_pfn;

	nr += end_pfn - start_pfn;
	}

	return nr;
	}

	static unsigned long calc_max_low_pfn(void)
	{
	int i;
	unsigned long tmp = pfn_base + (SRMMU_MAXMEM >> PAGE_SHIFT);
	unsigned long curr_pfn, last_pfn;

	last_pfn = (sp_banks[0].base_addr + sp_banks[0].num_bytes) >> PAGE_SHIFT;
	for (i = 1; sp_banks[i].num_bytes != 0; i++) {
	curr_pfn = sp_banks[i].base_addr >> PAGE_SHIFT;

	if (curr_pfn >= tmp) {
	if (last_pfn < tmp)
	tmp = last_pfn;
	break;
	}

	last_pfn = (sp_banks[i].base_addr + sp_banks[i].num_bytes) >> PAGE_SHIFT;
	}

	return tmp;
	}

	unsigned long __init bootmem_init(unsigned long *pages_avail)
	{
	unsigned long bootmap_size, start_pfn;
	unsigned long end_of_phys_memory = 0UL;
	unsigned long bootmap_pfn, bytes_avail, size;
	int i;

	bytes_avail = 0UL;
	for (i = 0; sp_banks[i].num_bytes != 0; i++) {
	end_of_phys_memory = sp_banks[i].base_addr +
	sp_banks[i].num_bytes;
	bytes_avail += sp_banks[i].num_bytes;
	if (cmdline_memory_size) {
	if (bytes_avail > cmdline_memory_size) {
	unsigned long slack = bytes_avail - cmdline_memory_size;

	bytes_avail -= slack;
	end_of_phys_memory -= slack;

	sp_banks[i].num_bytes -= slack;
	if (sp_banks[i].num_bytes == 0) {
	sp_banks[i].base_addr = 0xdeadbeef;
	} else {
	sp_banks[i+1].num_bytes = 0;
	sp_banks[i+1].base_addr = 0xdeadbeef;
	}
	break;
	}
	}
	}

	/* Start with page aligned address of last symbol in kernel
	* image.
	*/
	start_pfn = (unsigned long)__pa(PAGE_ALIGN((unsigned long) &_end));

	/* Now shift down to get the real physical page frame number. */
	start_pfn >>= PAGE_SHIFT;

	bootmap_pfn = start_pfn;

	max_pfn = end_of_phys_memory >> PAGE_SHIFT;

	max_low_pfn = max_pfn;
	highstart_pfn = highend_pfn = max_pfn;

	if (max_low_pfn > pfn_base + (SRMMU_MAXMEM >> PAGE_SHIFT)) {
	highstart_pfn = pfn_base + (SRMMU_MAXMEM >> PAGE_SHIFT);
	max_low_pfn = calc_max_low_pfn();
	printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
	calc_highpages() >> (20 - PAGE_SHIFT));
	}

	#ifdef CONFIG_BLK_DEV_INITRD
	/* Now have to check initial ramdisk, so that bootmap does not overwrite it */
	if (sparc_ramdisk_image) {
	if (sparc_ramdisk_image >= (unsigned long)&_end - 2 * PAGE_SIZE)
	sparc_ramdisk_image -= KERNBASE;
	initrd_start = sparc_ramdisk_image + phys_base;
	initrd_end = initrd_start + sparc_ramdisk_size;
	if (initrd_end > end_of_phys_memory) {
	printk(KERN_CRIT "initrd extends beyond end of memory "
	"(0x%016lx > 0x%016lx)\ndisabling initrd\n",
	initrd_end, end_of_phys_memory);
	initrd_start = 0;
	}
	if (initrd_start) {
	if (initrd_start >= (start_pfn << PAGE_SHIFT) &&
	initrd_start < (start_pfn << PAGE_SHIFT) + 2 * PAGE_SIZE)
	bootmap_pfn = PAGE_ALIGN (initrd_end) >> PAGE_SHIFT;
	}
	}
	#endif
	/* Initialize the boot-time allocator. */
	bootmap_size = init_bootmem_node(NODE_DATA(0), bootmap_pfn, pfn_base,
	max_low_pfn);

	/* Now register the available physical memory with the
	* allocator.
	*/
	*pages_avail = 0;
	for (i = 0; sp_banks[i].num_bytes != 0; i++) {
	unsigned long curr_pfn, last_pfn;

	curr_pfn = sp_banks[i].base_addr >> PAGE_SHIFT;
	if (curr_pfn >= max_low_pfn)
	break;

	last_pfn = (sp_banks[i].base_addr + sp_banks[i].num_bytes) >> PAGE_SHIFT;
	if (last_pfn > max_low_pfn)
	last_pfn = max_low_pfn;

	/*
	* .. finally, did all the rounding and playing
	* around just make the area go away?
	*/
	if (last_pfn <= curr_pfn)
	continue;

	size = (last_pfn - curr_pfn) << PAGE_SHIFT;
	*pages_avail += last_pfn - curr_pfn;

	free_bootmem(sp_banks[i].base_addr, size);
	}

	#ifdef CONFIG_BLK_DEV_INITRD
	if (initrd_start) {
	/* Reserve the initrd image area. */
	size = initrd_end - initrd_start;
	reserve_bootmem(initrd_start, size, BOOTMEM_DEFAULT);
	*pages_avail -= PAGE_ALIGN(size) >> PAGE_SHIFT;

	initrd_start = (initrd_start - phys_base) + PAGE_OFFSET;
	initrd_end = (initrd_end - phys_base) + PAGE_OFFSET;
	}
	#endif
	/* Reserve the kernel text/data/bss. */
	size = (start_pfn << PAGE_SHIFT) - phys_base;
	reserve_bootmem(phys_base, size, BOOTMEM_DEFAULT);
	*pages_avail -= PAGE_ALIGN(size) >> PAGE_SHIFT;

	/* Reserve the bootmem map. We do not account for it
	* in pages_avail because we will release that memory
	* in free_all_bootmem.
	*/
	size = bootmap_size;
	reserve_bootmem((bootmap_pfn << PAGE_SHIFT), size, BOOTMEM_DEFAULT);
	*pages_avail -= PAGE_ALIGN(size) >> PAGE_SHIFT;

	return max_pfn;
	}

	/*
	* paging_init() sets up the page tables: We call the MMU specific
	* init routine based upon the Sun model type on the Sparc.
	*
	*/
	extern void srmmu_paging_init(void);
	extern void device_scan(void);

	void __init paging_init(void)
	{
	srmmu_paging_init();
	prom_build_devicetree();
	of_fill_in_cpu_data();
	device_scan();
	}

	static void __init taint_real_pages(void)
	{
	int i;

	for (i = 0; sp_banks[i].num_bytes; i++) {
	unsigned long start, end;

	start = sp_banks[i].base_addr;
	end = start + sp_banks[i].num_bytes;

	while (start < end) {
	set_bit(start >> 20, sparc_valid_addr_bitmap);
	start += PAGE_SIZE;
	}
	}
	}

	static void map_high_region(unsigned long start_pfn, unsigned long end_pfn)
	{
	unsigned long tmp;

	#ifdef CONFIG_DEBUG_HIGHMEM
	printk("mapping high region %08lx - %08lx\n", start_pfn, end_pfn);
	#endif

	for (tmp = start_pfn; tmp < end_pfn; tmp++) {
	struct page *page = pfn_to_page(tmp);

	ClearPageReserved(page);
	init_page_count(page);
	__free_page(page);
	totalhigh_pages++;
	}
	}

	void __init mem_init(void)
	{
	int codepages = 0;
	int datapages = 0;
	int initpages = 0;
	int reservedpages = 0;
	int i;

	if (PKMAP_BASE+LAST_PKMAP*PAGE_SIZE >= FIXADDR_START) {
	prom_printf("BUG: fixmap and pkmap areas overlap\n");
	prom_printf("pkbase: 0x%lx pkend: 0x%lx fixstart 0x%lx\n",
	PKMAP_BASE,
	(unsigned long)PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
	FIXADDR_START);
	prom_printf("Please mail sparclinux@vger.kernel.org.\n");
	prom_halt();
	}


	/* Saves us work later. */
	memset((void *)&empty_zero_page, 0, PAGE_SIZE);

	i = last_valid_pfn >> ((20 - PAGE_SHIFT) + 5);
	i += 1;
	sparc_valid_addr_bitmap = (unsigned long *)
	__alloc_bootmem(i << 2, SMP_CACHE_BYTES, 0UL);

	if (sparc_valid_addr_bitmap == NULL) {
	prom_printf("mem_init: Cannot alloc valid_addr_bitmap.\n");
	prom_halt();
	}
	memset(sparc_valid_addr_bitmap, 0, i << 2);

	taint_real_pages();

	max_mapnr = last_valid_pfn - pfn_base;
	high_memory = __va(max_low_pfn << PAGE_SHIFT);

	totalram_pages = free_all_bootmem();

	for (i = 0; sp_banks[i].num_bytes != 0; i++) {
	unsigned long start_pfn = sp_banks[i].base_addr >> PAGE_SHIFT;
	unsigned long end_pfn = (sp_banks[i].base_addr + sp_banks[i].num_bytes) >> PAGE_SHIFT;

	num_physpages += sp_banks[i].num_bytes >> PAGE_SHIFT;

	if (end_pfn <= highstart_pfn)
	continue;

	if (start_pfn < highstart_pfn)
	start_pfn = highstart_pfn;

	map_high_region(start_pfn, end_pfn);
	}

	totalram_pages += totalhigh_pages;

	codepages = (((unsigned long) &_etext) - ((unsigned long)&_start));
	codepages = PAGE_ALIGN(codepages) >> PAGE_SHIFT;
	datapages = (((unsigned long) &_edata) - ((unsigned long)&_etext));
	datapages = PAGE_ALIGN(datapages) >> PAGE_SHIFT;
	initpages = (((unsigned long) &__init_end) - ((unsigned long) &__init_begin));
	initpages = PAGE_ALIGN(initpages) >> PAGE_SHIFT;

	/* Ignore memory holes for the purpose of counting reserved pages */
	for (i=0; i < max_low_pfn; i++)
	if (test_bit(i >> (20 - PAGE_SHIFT), sparc_valid_addr_bitmap)
	&& PageReserved(pfn_to_page(i)))
	reservedpages++;

	printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init, %ldk highmem)\n",
	nr_free_pages() << (PAGE_SHIFT-10),
	num_physpages << (PAGE_SHIFT - 10),
	codepages << (PAGE_SHIFT-10),
	reservedpages << (PAGE_SHIFT - 10),
	datapages << (PAGE_SHIFT-10),
	initpages << (PAGE_SHIFT-10),
	totalhigh_pages << (PAGE_SHIFT-10));
	}

	void free_initmem (void)
	{
	unsigned long addr;
	unsigned long freed;

	addr = (unsigned long)(&__init_begin);
	freed = (unsigned long)(&__init_end) - addr;
	for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
	struct page *p;

	memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
	p = virt_to_page(addr);

	ClearPageReserved(p);
	init_page_count(p);
	__free_page(p);
	totalram_pages++;
	num_physpages++;
	}
	printk(KERN_INFO "Freeing unused kernel memory: %ldk freed\n",
	freed >> 10);
	}

	#ifdef CONFIG_BLK_DEV_INITRD
	void free_initrd_mem(unsigned long start, unsigned long end)
	{
	if (start < end)
	printk(KERN_INFO "Freeing initrd memory: %ldk freed\n",
	(end - start) >> 10);
	for (; start < end; start += PAGE_SIZE) {
	struct page *p;

	memset((void *)start, POISON_FREE_INITMEM, PAGE_SIZE);
	p = virt_to_page(start);

	ClearPageReserved(p);
	init_page_count(p);
	__free_page(p);
	totalram_pages++;
	num_physpages++;
	}
	}
	#endif

	void sparc_flush_page_to_ram(struct page *page)
	{
	unsigned long vaddr = (unsigned long)page_address(page);

	if (vaddr)
	__flush_page_to_ram(vaddr);
	}
	EXPORT_SYMBOL(sparc_flush_page_to_ram);