arch/mips/mm/init.c - kernel/msm-4.9 - Gitiles

 /*
  * 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.
  *
  * Copyright (C) 1994 - 2000 Ralf Baechle
  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
  * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
  * Copyright (C) 2000 MIPS Technologies, Inc.  All rights reserved.
  */
 #include <linux/bug.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/signal.h>
 #include <linux/sched.h>
 #include <linux/smp.h>
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/string.h>
 #include <linux/types.h>
 #include <linux/pagemap.h>
 #include <linux/ptrace.h>
 #include <linux/mman.h>
 #include <linux/mm.h>
 #include <linux/bootmem.h>
 #include <linux/highmem.h>
 #include <linux/swap.h>
 #include <linux/proc_fs.h>
 #include <linux/pfn.h>
 #include <linux/hardirq.h>
 #include <linux/gfp.h>

 #include <asm/asm-offsets.h>
 #include <asm/bootinfo.h>
 #include <asm/cachectl.h>
 #include <asm/cpu.h>
 #include <asm/dma.h>
 #include <asm/kmap_types.h>
 #include <asm/mmu_context.h>
 #include <asm/sections.h>
 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
 #include <asm/tlb.h>
 #include <asm/fixmap.h>

 /* Atomicity and interruptability */
 #ifdef CONFIG_MIPS_MT_SMTC

 #include <asm/mipsmtregs.h>

 #define ENTER_CRITICAL(flags) \
 	{ \
 	unsigned int mvpflags; \
 	local_irq_save(flags);\
 	mvpflags = dvpe()
 #define EXIT_CRITICAL(flags) \
 	evpe(mvpflags); \
 	local_irq_restore(flags); \
 	}
 #else

 #define ENTER_CRITICAL(flags) local_irq_save(flags)
 #define EXIT_CRITICAL(flags) local_irq_restore(flags)

 #endif /* CONFIG_MIPS_MT_SMTC */

 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);

 /*
  * We have up to 8 empty zeroed pages so we can map one of the right colour
  * when needed.  This is necessary only on R4000 / R4400 SC and MC versions
  * where we have to avoid VCED / VECI exceptions for good performance at
  * any price.  Since page is never written to after the initialization we
  * don't have to care about aliases on other CPUs.
  */
 unsigned long empty_zero_page, zero_page_mask;
 EXPORT_SYMBOL_GPL(empty_zero_page);

 /*
  * Not static inline because used by IP27 special magic initialization code
  */
 unsigned long setup_zero_pages(void)
 {
 	unsigned int order;
 	unsigned long size;
 	struct page *page;

 	if (cpu_has_vce)
 		order = 3;
 	else
 		order = 0;

 	empty_zero_page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
 	if (!empty_zero_page)
 		panic("Oh boy, that early out of memory?");

 	page = virt_to_page((void *)empty_zero_page);
 	split_page(page, order);
 	while (page < virt_to_page((void *)(empty_zero_page + (PAGE_SIZE << order)))) {
 		SetPageReserved(page);
 		page++;
 	}

 	size = PAGE_SIZE << order;
 	zero_page_mask = (size - 1) & PAGE_MASK;

 	return 1UL << order;
 }

 #ifdef CONFIG_MIPS_MT_SMTC
 static pte_t *kmap_coherent_pte;
 static void __init kmap_coherent_init(void)
 {
 	unsigned long vaddr;

 	/* cache the first coherent kmap pte */
 	vaddr = __fix_to_virt(FIX_CMAP_BEGIN);
 	kmap_coherent_pte = kmap_get_fixmap_pte(vaddr);
 }
 #else
 static inline void kmap_coherent_init(void) {}
 #endif

 void *kmap_coherent(struct page *page, unsigned long addr)
 {
 	enum fixed_addresses idx;
 	unsigned long vaddr, flags, entrylo;
 	unsigned long old_ctx;
 	pte_t pte;
 	int tlbidx;

 	BUG_ON(Page_dcache_dirty(page));

 	inc_preempt_count();
 	idx = (addr >> PAGE_SHIFT) & (FIX_N_COLOURS - 1);
 #ifdef CONFIG_MIPS_MT_SMTC
 	idx += FIX_N_COLOURS * smp_processor_id() +
 		(in_interrupt() ? (FIX_N_COLOURS * NR_CPUS) : 0);
 #else
 	idx += in_interrupt() ? FIX_N_COLOURS : 0;
 #endif
 	vaddr = __fix_to_virt(FIX_CMAP_END - idx);
 	pte = mk_pte(page, PAGE_KERNEL);
 #if defined(CONFIG_64BIT_PHYS_ADDR) && defined(CONFIG_CPU_MIPS32)
 	entrylo = pte.pte_high;
 #else
 	entrylo = pte_to_entrylo(pte_val(pte));
 #endif

 	ENTER_CRITICAL(flags);
 	old_ctx = read_c0_entryhi();
 	write_c0_entryhi(vaddr & (PAGE_MASK << 1));
 	write_c0_entrylo0(entrylo);
 	write_c0_entrylo1(entrylo);
 #ifdef CONFIG_MIPS_MT_SMTC
 	set_pte(kmap_coherent_pte - (FIX_CMAP_END - idx), pte);
 	/* preload TLB instead of local_flush_tlb_one() */
 	mtc0_tlbw_hazard();
 	tlb_probe();
 	tlb_probe_hazard();
 	tlbidx = read_c0_index();
 	mtc0_tlbw_hazard();
 	if (tlbidx < 0)
 		tlb_write_random();
 	else
 		tlb_write_indexed();
 #else
 	tlbidx = read_c0_wired();
 	write_c0_wired(tlbidx + 1);
 	write_c0_index(tlbidx);
 	mtc0_tlbw_hazard();
 	tlb_write_indexed();
 #endif
 	tlbw_use_hazard();
 	write_c0_entryhi(old_ctx);
 	EXIT_CRITICAL(flags);

 	return (void*) vaddr;
 }

 #define UNIQUE_ENTRYHI(idx) (CKSEG0 + ((idx) << (PAGE_SHIFT + 1)))

 void kunmap_coherent(void)
 {
 #ifndef CONFIG_MIPS_MT_SMTC
 	unsigned int wired;
 	unsigned long flags, old_ctx;

 	ENTER_CRITICAL(flags);
 	old_ctx = read_c0_entryhi();
 	wired = read_c0_wired() - 1;
 	write_c0_wired(wired);
 	write_c0_index(wired);
 	write_c0_entryhi(UNIQUE_ENTRYHI(wired));
 	write_c0_entrylo0(0);
 	write_c0_entrylo1(0);
 	mtc0_tlbw_hazard();
 	tlb_write_indexed();
 	tlbw_use_hazard();
 	write_c0_entryhi(old_ctx);
 	EXIT_CRITICAL(flags);
 #endif
 	dec_preempt_count();
 	preempt_check_resched();
 }

 void copy_user_highpage(struct page *to, struct page *from,
 	unsigned long vaddr, struct vm_area_struct *vma)
 {
 	void *vfrom, *vto;

 	vto = kmap_atomic(to, KM_USER1);
 	if (cpu_has_dc_aliases &&
 	    page_mapped(from) && !Page_dcache_dirty(from)) {
 		vfrom = kmap_coherent(from, vaddr);
 		copy_page(vto, vfrom);
 		kunmap_coherent();
 	} else {
 		vfrom = kmap_atomic(from, KM_USER0);
 		copy_page(vto, vfrom);
 		kunmap_atomic(vfrom, KM_USER0);
 	}
 	if ((!cpu_has_ic_fills_f_dc) ||
 	    pages_do_alias((unsigned long)vto, vaddr & PAGE_MASK))
 		flush_data_cache_page((unsigned long)vto);
 	kunmap_atomic(vto, KM_USER1);
 	/* Make sure this page is cleared on other CPU's too before using it */
 	smp_wmb();
 }

 void copy_to_user_page(struct vm_area_struct *vma,
 	struct page *page, unsigned long vaddr, void *dst, const void *src,
 	unsigned long len)
 {
 	if (cpu_has_dc_aliases &&
 	    page_mapped(page) && !Page_dcache_dirty(page)) {
 		void *vto = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
 		memcpy(vto, src, len);
 		kunmap_coherent();
 	} else {
 		memcpy(dst, src, len);
 		if (cpu_has_dc_aliases)
 			SetPageDcacheDirty(page);
 	}
 	if ((vma->vm_flags & VM_EXEC) && !cpu_has_ic_fills_f_dc)
 		flush_cache_page(vma, vaddr, page_to_pfn(page));
 }

 void copy_from_user_page(struct vm_area_struct *vma,
 	struct page *page, unsigned long vaddr, void *dst, const void *src,
 	unsigned long len)
 {
 	if (cpu_has_dc_aliases &&
 	    page_mapped(page) && !Page_dcache_dirty(page)) {
 		void *vfrom = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
 		memcpy(dst, vfrom, len);
 		kunmap_coherent();
 	} else {
 		memcpy(dst, src, len);
 		if (cpu_has_dc_aliases)
 			SetPageDcacheDirty(page);
 	}
 }

 void __init fixrange_init(unsigned long start, unsigned long end,
 	pgd_t *pgd_base)
 {
 #if defined(CONFIG_HIGHMEM) || defined(CONFIG_MIPS_MT_SMTC)
 	pgd_t *pgd;
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;
 	int i, j, k;
 	unsigned long vaddr;

 	vaddr = start;
 	i = __pgd_offset(vaddr);
 	j = __pud_offset(vaddr);
 	k = __pmd_offset(vaddr);
 	pgd = pgd_base + i;

 	for ( ; (i < PTRS_PER_PGD) && (vaddr != end); pgd++, i++) {
 		pud = (pud_t *)pgd;
 		for ( ; (j < PTRS_PER_PUD) && (vaddr != end); pud++, j++) {
 			pmd = (pmd_t *)pud;
 			for (; (k < PTRS_PER_PMD) && (vaddr != end); pmd++, k++) {
 				if (pmd_none(*pmd)) {
 					pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 					set_pmd(pmd, __pmd((unsigned long)pte));
 					BUG_ON(pte != pte_offset_kernel(pmd, 0));
 				}
 				vaddr += PMD_SIZE;
 			}
 			k = 0;
 		}
 		j = 0;
 	}
 #endif
 }

 #ifndef CONFIG_NEED_MULTIPLE_NODES
 int page_is_ram(unsigned long pagenr)
 {
 	int i;

 	for (i = 0; i < boot_mem_map.nr_map; i++) {
 		unsigned long addr, end;

 		if (boot_mem_map.map[i].type != BOOT_MEM_RAM)
 			/* not usable memory */
 			continue;

 		addr = PFN_UP(boot_mem_map.map[i].addr);
 		end = PFN_DOWN(boot_mem_map.map[i].addr +
 			       boot_mem_map.map[i].size);

 		if (pagenr >= addr && pagenr < end)
 			return 1;
 	}

 	return 0;
 }

 void __init paging_init(void)
 {
 	unsigned long max_zone_pfns[MAX_NR_ZONES];
 	unsigned long lastpfn __maybe_unused;

 	pagetable_init();

 #ifdef CONFIG_HIGHMEM
 	kmap_init();
 #endif
 	kmap_coherent_init();

 #ifdef CONFIG_ZONE_DMA
 	max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN;
 #endif
 #ifdef CONFIG_ZONE_DMA32
 	max_zone_pfns[ZONE_DMA32] = MAX_DMA32_PFN;
 #endif
 	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
 	lastpfn = max_low_pfn;
 #ifdef CONFIG_HIGHMEM
 	max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
 	lastpfn = highend_pfn;

 	if (cpu_has_dc_aliases && max_low_pfn != highend_pfn) {
 		printk(KERN_WARNING "This processor doesn't support highmem."
 		       " %ldk highmem ignored\n",
 		       (highend_pfn - max_low_pfn) << (PAGE_SHIFT - 10));
 		max_zone_pfns[ZONE_HIGHMEM] = max_low_pfn;
 		lastpfn = max_low_pfn;
 	}
 #endif

 	free_area_init_nodes(max_zone_pfns);
 }

 #ifdef CONFIG_64BIT
 static struct kcore_list kcore_kseg0;
 #endif

 void __init mem_init(void)
 {
 	unsigned long codesize, reservedpages, datasize, initsize;
 	unsigned long tmp, ram;

 #ifdef CONFIG_HIGHMEM
 #ifdef CONFIG_DISCONTIGMEM
 #error "CONFIG_HIGHMEM and CONFIG_DISCONTIGMEM dont work together yet"
 #endif
 	max_mapnr = highend_pfn;
 #else
 	max_mapnr = max_low_pfn;
 #endif
 	high_memory = (void *) __va(max_low_pfn << PAGE_SHIFT);

 	totalram_pages += free_all_bootmem();
 	totalram_pages -= setup_zero_pages();	/* Setup zeroed pages.  */

 	reservedpages = ram = 0;
 	for (tmp = 0; tmp < max_low_pfn; tmp++)
 		if (page_is_ram(tmp)) {
 			ram++;
 			if (PageReserved(pfn_to_page(tmp)))
 				reservedpages++;
 		}
 	num_physpages = ram;

 #ifdef CONFIG_HIGHMEM
 	for (tmp = highstart_pfn; tmp < highend_pfn; tmp++) {
 		struct page *page = pfn_to_page(tmp);

 		if (!page_is_ram(tmp)) {
 			SetPageReserved(page);
 			continue;
 		}
 		ClearPageReserved(page);
 		init_page_count(page);
 		__free_page(page);
 		totalhigh_pages++;
 	}
 	totalram_pages += totalhigh_pages;
 	num_physpages += totalhigh_pages;
 #endif

 	codesize =  (unsigned long) &_etext - (unsigned long) &_text;
 	datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
 	initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;

 #ifdef CONFIG_64BIT
 	if ((unsigned long) &_text > (unsigned long) CKSEG0)
 		/* The -4 is a hack so that user tools don't have to handle
 		   the overflow.  */
 		kclist_add(&kcore_kseg0, (void *) CKSEG0,
 				0x80000000 - 4, KCORE_TEXT);
 #endif

 	printk(KERN_INFO "Memory: %luk/%luk available (%ldk kernel code, "
 	       "%ldk reserved, %ldk data, %ldk init, %ldk highmem)\n",
 	       nr_free_pages() << (PAGE_SHIFT-10),
 	       ram << (PAGE_SHIFT-10),
 	       codesize >> 10,
 	       reservedpages << (PAGE_SHIFT-10),
 	       datasize >> 10,
 	       initsize >> 10,
 	       totalhigh_pages << (PAGE_SHIFT-10));
 }
 #endif /* !CONFIG_NEED_MULTIPLE_NODES */

 void free_init_pages(const char *what, unsigned long begin, unsigned long end)
 {
 	unsigned long pfn;

 	for (pfn = PFN_UP(begin); pfn < PFN_DOWN(end); pfn++) {
 		struct page *page = pfn_to_page(pfn);
 		void *addr = phys_to_virt(PFN_PHYS(pfn));

 		ClearPageReserved(page);
 		init_page_count(page);
 		memset(addr, POISON_FREE_INITMEM, PAGE_SIZE);
 		__free_page(page);
 		totalram_pages++;
 	}
 	printk(KERN_INFO "Freeing %s: %ldk freed\n", what, (end - begin) >> 10);
 }

 #ifdef CONFIG_BLK_DEV_INITRD
 void free_initrd_mem(unsigned long start, unsigned long end)
 {
 	free_init_pages("initrd memory",
 			virt_to_phys((void *)start),
 			virt_to_phys((void *)end));
 }
 #endif

 void __init_refok free_initmem(void)
 {
 	prom_free_prom_memory();
 	free_init_pages("unused kernel memory",
 			__pa_symbol(&__init_begin),
 			__pa_symbol(&__init_end));
 }

 #ifndef CONFIG_MIPS_PGD_C0_CONTEXT
 unsigned long pgd_current[NR_CPUS];
 #endif
 /*
  * On 64-bit we've got three-level pagetables with a slightly
  * different layout ...
  */
 #define __page_aligned(order) __attribute__((__aligned__(PAGE_SIZE<<order)))

 /*
  * gcc 3.3 and older have trouble determining that PTRS_PER_PGD and PGD_ORDER
  * are constants.  So we use the variants from asm-offset.h until that gcc
  * will officially be retired.
  */
 pgd_t swapper_pg_dir[_PTRS_PER_PGD] __page_aligned(_PGD_ORDER);
 #ifndef __PAGETABLE_PMD_FOLDED
 pmd_t invalid_pmd_table[PTRS_PER_PMD] __page_aligned(PMD_ORDER);
 #endif
 pte_t invalid_pte_table[PTRS_PER_PTE] __page_aligned(PTE_ORDER);
	/*
	* 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.
	*
	* Copyright (C) 1994 - 2000 Ralf Baechle
	* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
	* Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
	* Copyright (C) 2000 MIPS Technologies, Inc. All rights reserved.
	*/
	#include <linux/bug.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/signal.h>
	#include <linux/sched.h>
	#include <linux/smp.h>
	#include <linux/kernel.h>
	#include <linux/errno.h>
	#include <linux/string.h>
	#include <linux/types.h>
	#include <linux/pagemap.h>
	#include <linux/ptrace.h>
	#include <linux/mman.h>
	#include <linux/mm.h>
	#include <linux/bootmem.h>
	#include <linux/highmem.h>
	#include <linux/swap.h>
	#include <linux/proc_fs.h>
	#include <linux/pfn.h>
	#include <linux/hardirq.h>
	#include <linux/gfp.h>

	#include <asm/asm-offsets.h>
	#include <asm/bootinfo.h>
	#include <asm/cachectl.h>
	#include <asm/cpu.h>
	#include <asm/dma.h>
	#include <asm/kmap_types.h>
	#include <asm/mmu_context.h>
	#include <asm/sections.h>
	#include <asm/pgtable.h>
	#include <asm/pgalloc.h>
	#include <asm/tlb.h>
	#include <asm/fixmap.h>

	/* Atomicity and interruptability */
	#ifdef CONFIG_MIPS_MT_SMTC

	#include <asm/mipsmtregs.h>

	#define ENTER_CRITICAL(flags) \
	{ \
	unsigned int mvpflags; \
	local_irq_save(flags);\
	mvpflags = dvpe()
	#define EXIT_CRITICAL(flags) \
	evpe(mvpflags); \
	local_irq_restore(flags); \
	}
	#else

	#define ENTER_CRITICAL(flags) local_irq_save(flags)
	#define EXIT_CRITICAL(flags) local_irq_restore(flags)

	#endif /* CONFIG_MIPS_MT_SMTC */

	DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);

	/*
	* We have up to 8 empty zeroed pages so we can map one of the right colour
	* when needed. This is necessary only on R4000 / R4400 SC and MC versions
	* where we have to avoid VCED / VECI exceptions for good performance at
	* any price. Since page is never written to after the initialization we
	* don't have to care about aliases on other CPUs.
	*/
	unsigned long empty_zero_page, zero_page_mask;
	EXPORT_SYMBOL_GPL(empty_zero_page);

	/*
	* Not static inline because used by IP27 special magic initialization code
	*/
	unsigned long setup_zero_pages(void)
	{
	unsigned int order;
	unsigned long size;
	struct page *page;

	if (cpu_has_vce)
	order = 3;
	else
	order = 0;

	empty_zero_page = __get_free_pages(GFP_KERNEL \| __GFP_ZERO, order);
	if (!empty_zero_page)
	panic("Oh boy, that early out of memory?");

	page = virt_to_page((void *)empty_zero_page);
	split_page(page, order);
	while (page < virt_to_page((void *)(empty_zero_page + (PAGE_SIZE << order)))) {
	SetPageReserved(page);
	page++;
	}

	size = PAGE_SIZE << order;
	zero_page_mask = (size - 1) & PAGE_MASK;

	return 1UL << order;
	}

	#ifdef CONFIG_MIPS_MT_SMTC
	static pte_t *kmap_coherent_pte;
	static void __init kmap_coherent_init(void)
	{
	unsigned long vaddr;

	/* cache the first coherent kmap pte */
	vaddr = __fix_to_virt(FIX_CMAP_BEGIN);
	kmap_coherent_pte = kmap_get_fixmap_pte(vaddr);
	}
	#else
	static inline void kmap_coherent_init(void) {}
	#endif

	void kmap_coherent(struct page page, unsigned long addr)
	{
	enum fixed_addresses idx;
	unsigned long vaddr, flags, entrylo;
	unsigned long old_ctx;
	pte_t pte;
	int tlbidx;

	BUG_ON(Page_dcache_dirty(page));

	inc_preempt_count();
	idx = (addr >> PAGE_SHIFT) & (FIX_N_COLOURS - 1);
	#ifdef CONFIG_MIPS_MT_SMTC
	idx += FIX_N_COLOURS * smp_processor_id() +
	(in_interrupt() ? (FIX_N_COLOURS * NR_CPUS) : 0);
	#else
	idx += in_interrupt() ? FIX_N_COLOURS : 0;
	#endif
	vaddr = __fix_to_virt(FIX_CMAP_END - idx);
	pte = mk_pte(page, PAGE_KERNEL);
	#if defined(CONFIG_64BIT_PHYS_ADDR) && defined(CONFIG_CPU_MIPS32)
	entrylo = pte.pte_high;
	#else
	entrylo = pte_to_entrylo(pte_val(pte));
	#endif

	ENTER_CRITICAL(flags);
	old_ctx = read_c0_entryhi();
	write_c0_entryhi(vaddr & (PAGE_MASK << 1));
	write_c0_entrylo0(entrylo);
	write_c0_entrylo1(entrylo);
	#ifdef CONFIG_MIPS_MT_SMTC
	set_pte(kmap_coherent_pte - (FIX_CMAP_END - idx), pte);
	/* preload TLB instead of local_flush_tlb_one() */
	mtc0_tlbw_hazard();
	tlb_probe();
	tlb_probe_hazard();
	tlbidx = read_c0_index();
	mtc0_tlbw_hazard();
	if (tlbidx < 0)
	tlb_write_random();
	else
	tlb_write_indexed();
	#else
	tlbidx = read_c0_wired();
	write_c0_wired(tlbidx + 1);
	write_c0_index(tlbidx);
	mtc0_tlbw_hazard();
	tlb_write_indexed();
	#endif
	tlbw_use_hazard();
	write_c0_entryhi(old_ctx);
	EXIT_CRITICAL(flags);

	return (void*) vaddr;
	}

	#define UNIQUE_ENTRYHI(idx) (CKSEG0 + ((idx) << (PAGE_SHIFT + 1)))

	void kunmap_coherent(void)
	{
	#ifndef CONFIG_MIPS_MT_SMTC
	unsigned int wired;
	unsigned long flags, old_ctx;

	ENTER_CRITICAL(flags);
	old_ctx = read_c0_entryhi();
	wired = read_c0_wired() - 1;
	write_c0_wired(wired);
	write_c0_index(wired);
	write_c0_entryhi(UNIQUE_ENTRYHI(wired));
	write_c0_entrylo0(0);
	write_c0_entrylo1(0);
	mtc0_tlbw_hazard();
	tlb_write_indexed();
	tlbw_use_hazard();
	write_c0_entryhi(old_ctx);
	EXIT_CRITICAL(flags);
	#endif
	dec_preempt_count();
	preempt_check_resched();
	}

	void copy_user_highpage(struct page to, struct page from,
	unsigned long vaddr, struct vm_area_struct *vma)
	{
	void vfrom, vto;

	vto = kmap_atomic(to, KM_USER1);
	if (cpu_has_dc_aliases &&
	page_mapped(from) && !Page_dcache_dirty(from)) {
	vfrom = kmap_coherent(from, vaddr);
	copy_page(vto, vfrom);
	kunmap_coherent();
	} else {
	vfrom = kmap_atomic(from, KM_USER0);
	copy_page(vto, vfrom);
	kunmap_atomic(vfrom, KM_USER0);
	}
	if ((!cpu_has_ic_fills_f_dc) \|\|
	pages_do_alias((unsigned long)vto, vaddr & PAGE_MASK))
	flush_data_cache_page((unsigned long)vto);
	kunmap_atomic(vto, KM_USER1);
	/* Make sure this page is cleared on other CPU's too before using it */
	smp_wmb();
	}

	void copy_to_user_page(struct vm_area_struct *vma,
	struct page page, unsigned long vaddr, void dst, const void *src,
	unsigned long len)
	{
	if (cpu_has_dc_aliases &&
	page_mapped(page) && !Page_dcache_dirty(page)) {
	void *vto = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
	memcpy(vto, src, len);
	kunmap_coherent();
	} else {
	memcpy(dst, src, len);
	if (cpu_has_dc_aliases)
	SetPageDcacheDirty(page);
	}
	if ((vma->vm_flags & VM_EXEC) && !cpu_has_ic_fills_f_dc)
	flush_cache_page(vma, vaddr, page_to_pfn(page));
	}

	void copy_from_user_page(struct vm_area_struct *vma,
	struct page page, unsigned long vaddr, void dst, const void *src,
	unsigned long len)
	{
	if (cpu_has_dc_aliases &&
	page_mapped(page) && !Page_dcache_dirty(page)) {
	void *vfrom = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
	memcpy(dst, vfrom, len);
	kunmap_coherent();
	} else {
	memcpy(dst, src, len);
	if (cpu_has_dc_aliases)
	SetPageDcacheDirty(page);
	}
	}

	void __init fixrange_init(unsigned long start, unsigned long end,
	pgd_t *pgd_base)
	{
	#if defined(CONFIG_HIGHMEM) \|\| defined(CONFIG_MIPS_MT_SMTC)
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;
	int i, j, k;
	unsigned long vaddr;

	vaddr = start;
	i = __pgd_offset(vaddr);
	j = __pud_offset(vaddr);
	k = __pmd_offset(vaddr);
	pgd = pgd_base + i;

	for ( ; (i < PTRS_PER_PGD) && (vaddr != end); pgd++, i++) {
	pud = (pud_t *)pgd;
	for ( ; (j < PTRS_PER_PUD) && (vaddr != end); pud++, j++) {
	pmd = (pmd_t *)pud;
	for (; (k < PTRS_PER_PMD) && (vaddr != end); pmd++, k++) {
	if (pmd_none(*pmd)) {
	pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
	set_pmd(pmd, __pmd((unsigned long)pte));
	BUG_ON(pte != pte_offset_kernel(pmd, 0));
	}
	vaddr += PMD_SIZE;
	}
	k = 0;
	}
	j = 0;
	}
	#endif
	}

	#ifndef CONFIG_NEED_MULTIPLE_NODES
	int page_is_ram(unsigned long pagenr)
	{
	int i;

	for (i = 0; i < boot_mem_map.nr_map; i++) {
	unsigned long addr, end;

	if (boot_mem_map.map[i].type != BOOT_MEM_RAM)
	/* not usable memory */
	continue;

	addr = PFN_UP(boot_mem_map.map[i].addr);
	end = PFN_DOWN(boot_mem_map.map[i].addr +
	boot_mem_map.map[i].size);

	if (pagenr >= addr && pagenr < end)
	return 1;
	}

	return 0;
	}

	void __init paging_init(void)
	{
	unsigned long max_zone_pfns[MAX_NR_ZONES];
	unsigned long lastpfn __maybe_unused;

	pagetable_init();

	#ifdef CONFIG_HIGHMEM
	kmap_init();
	#endif
	kmap_coherent_init();

	#ifdef CONFIG_ZONE_DMA
	max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN;
	#endif
	#ifdef CONFIG_ZONE_DMA32
	max_zone_pfns[ZONE_DMA32] = MAX_DMA32_PFN;
	#endif
	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
	lastpfn = max_low_pfn;
	#ifdef CONFIG_HIGHMEM
	max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
	lastpfn = highend_pfn;

	if (cpu_has_dc_aliases && max_low_pfn != highend_pfn) {
	printk(KERN_WARNING "This processor doesn't support highmem."
	" %ldk highmem ignored\n",
	(highend_pfn - max_low_pfn) << (PAGE_SHIFT - 10));
	max_zone_pfns[ZONE_HIGHMEM] = max_low_pfn;
	lastpfn = max_low_pfn;
	}
	#endif

	free_area_init_nodes(max_zone_pfns);
	}

	#ifdef CONFIG_64BIT
	static struct kcore_list kcore_kseg0;
	#endif

	void __init mem_init(void)
	{
	unsigned long codesize, reservedpages, datasize, initsize;
	unsigned long tmp, ram;

	#ifdef CONFIG_HIGHMEM
	#ifdef CONFIG_DISCONTIGMEM
	#error "CONFIG_HIGHMEM and CONFIG_DISCONTIGMEM dont work together yet"
	#endif
	max_mapnr = highend_pfn;
	#else
	max_mapnr = max_low_pfn;
	#endif
	high_memory = (void *) __va(max_low_pfn << PAGE_SHIFT);

	totalram_pages += free_all_bootmem();
	totalram_pages -= setup_zero_pages(); /* Setup zeroed pages. */

	reservedpages = ram = 0;
	for (tmp = 0; tmp < max_low_pfn; tmp++)
	if (page_is_ram(tmp)) {
	ram++;
	if (PageReserved(pfn_to_page(tmp)))
	reservedpages++;
	}
	num_physpages = ram;

	#ifdef CONFIG_HIGHMEM
	for (tmp = highstart_pfn; tmp < highend_pfn; tmp++) {
	struct page *page = pfn_to_page(tmp);

	if (!page_is_ram(tmp)) {
	SetPageReserved(page);
	continue;
	}
	ClearPageReserved(page);
	init_page_count(page);
	__free_page(page);
	totalhigh_pages++;
	}
	totalram_pages += totalhigh_pages;
	num_physpages += totalhigh_pages;
	#endif

	codesize = (unsigned long) &_etext - (unsigned long) &_text;
	datasize = (unsigned long) &_edata - (unsigned long) &_etext;
	initsize = (unsigned long) &__init_end - (unsigned long) &__init_begin;

	#ifdef CONFIG_64BIT
	if ((unsigned long) &_text > (unsigned long) CKSEG0)
	/* The -4 is a hack so that user tools don't have to handle
	the overflow. */
	kclist_add(&kcore_kseg0, (void *) CKSEG0,
	0x80000000 - 4, KCORE_TEXT);
	#endif

	printk(KERN_INFO "Memory: %luk/%luk available (%ldk kernel code, "
	"%ldk reserved, %ldk data, %ldk init, %ldk highmem)\n",
	nr_free_pages() << (PAGE_SHIFT-10),
	ram << (PAGE_SHIFT-10),
	codesize >> 10,
	reservedpages << (PAGE_SHIFT-10),
	datasize >> 10,
	initsize >> 10,
	totalhigh_pages << (PAGE_SHIFT-10));
	}
	#endif /* !CONFIG_NEED_MULTIPLE_NODES */

	void free_init_pages(const char *what, unsigned long begin, unsigned long end)
	{
	unsigned long pfn;

	for (pfn = PFN_UP(begin); pfn < PFN_DOWN(end); pfn++) {
	struct page *page = pfn_to_page(pfn);
	void *addr = phys_to_virt(PFN_PHYS(pfn));

	ClearPageReserved(page);
	init_page_count(page);
	memset(addr, POISON_FREE_INITMEM, PAGE_SIZE);
	__free_page(page);
	totalram_pages++;
	}
	printk(KERN_INFO "Freeing %s: %ldk freed\n", what, (end - begin) >> 10);
	}

	#ifdef CONFIG_BLK_DEV_INITRD
	void free_initrd_mem(unsigned long start, unsigned long end)
	{
	free_init_pages("initrd memory",
	virt_to_phys((void *)start),
	virt_to_phys((void *)end));
	}
	#endif

	void __init_refok free_initmem(void)
	{
	prom_free_prom_memory();
	free_init_pages("unused kernel memory",
	__pa_symbol(&__init_begin),
	__pa_symbol(&__init_end));
	}

	#ifndef CONFIG_MIPS_PGD_C0_CONTEXT
	unsigned long pgd_current[NR_CPUS];
	#endif
	/*
	* On 64-bit we've got three-level pagetables with a slightly
	* different layout ...
	*/
	#define __page_aligned(order) __attribute__((__aligned__(PAGE_SIZE<<order)))

	/*
	* gcc 3.3 and older have trouble determining that PTRS_PER_PGD and PGD_ORDER
	* are constants. So we use the variants from asm-offset.h until that gcc
	* will officially be retired.
	*/
	pgd_t swapper_pg_dir[_PTRS_PER_PGD] __page_aligned(_PGD_ORDER);
	#ifndef __PAGETABLE_PMD_FOLDED
	pmd_t invalid_pmd_table[PTRS_PER_PMD] __page_aligned(PMD_ORDER);
	#endif
	pte_t invalid_pte_table[PTRS_PER_PTE] __page_aligned(PTE_ORDER);