arch/sh/mm/init.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * linux/arch/sh/mm/init.c
  *
  *  Copyright (C) 1999  Niibe Yutaka
  *  Copyright (C) 2002 - 2011  Paul Mundt
  *
  *  Based on linux/arch/i386/mm/init.c:
  *   Copyright (C) 1995  Linus Torvalds
  */
 #include <linux/mm.h>
 #include <linux/swap.h>
 #include <linux/init.h>
 #include <linux/gfp.h>
 #include <linux/memblock.h>
 #include <linux/proc_fs.h>
 #include <linux/pagemap.h>
 #include <linux/percpu.h>
 #include <linux/io.h>
 #include <linux/dma-mapping.h>
 #include <linux/export.h>
 #include <asm/mmu_context.h>
 #include <asm/mmzone.h>
 #include <asm/kexec.h>
 #include <asm/tlb.h>
 #include <asm/cacheflush.h>
 #include <asm/sections.h>
 #include <asm/setup.h>
 #include <asm/cache.h>
 #include <asm/pgalloc.h>
 #include <linux/sizes.h>
 #include "ioremap.h"

 pgd_t swapper_pg_dir[PTRS_PER_PGD];

 void __init generic_mem_init(void)
 {
 	memblock_add(__MEMORY_START, __MEMORY_SIZE);
 }

 void __init __weak plat_mem_setup(void)
 {
 	/* Nothing to see here, move along. */
 }

 #ifdef CONFIG_MMU
 static pte_t *__get_pte_phys(unsigned long addr)
 {
 	pgd_t *pgd;
 	p4d_t *p4d;
 	pud_t *pud;
 	pmd_t *pmd;

 	pgd = pgd_offset_k(addr);
 	if (pgd_none(*pgd)) {
 		pgd_ERROR(*pgd);
 		return NULL;
 	}

 	p4d = p4d_alloc(NULL, pgd, addr);
 	if (unlikely(!p4d)) {
 		p4d_ERROR(*p4d);
 		return NULL;
 	}

 	pud = pud_alloc(NULL, p4d, addr);
 	if (unlikely(!pud)) {
 		pud_ERROR(*pud);
 		return NULL;
 	}

 	pmd = pmd_alloc(NULL, pud, addr);
 	if (unlikely(!pmd)) {
 		pmd_ERROR(*pmd);
 		return NULL;
 	}

 	return pte_offset_kernel(pmd, addr);
 }

 static void set_pte_phys(unsigned long addr, unsigned long phys, pgprot_t prot)
 {
 	pte_t *pte;

 	pte = __get_pte_phys(addr);
 	if (!pte_none(*pte)) {
 		pte_ERROR(*pte);
 		return;
 	}

 	set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, prot));
 	local_flush_tlb_one(get_asid(), addr);

 	if (pgprot_val(prot) & _PAGE_WIRED)
 		tlb_wire_entry(NULL, addr, *pte);
 }

 static void clear_pte_phys(unsigned long addr, pgprot_t prot)
 {
 	pte_t *pte;

 	pte = __get_pte_phys(addr);

 	if (pgprot_val(prot) & _PAGE_WIRED)
 		tlb_unwire_entry();

 	set_pte(pte, pfn_pte(0, __pgprot(0)));
 	local_flush_tlb_one(get_asid(), addr);
 }

 void __set_fixmap(enum fixed_addresses idx, unsigned long phys, pgprot_t prot)
 {
 	unsigned long address = __fix_to_virt(idx);

 	if (idx >= __end_of_fixed_addresses) {
 		BUG();
 		return;
 	}

 	set_pte_phys(address, phys, prot);
 }

 void __clear_fixmap(enum fixed_addresses idx, pgprot_t prot)
 {
 	unsigned long address = __fix_to_virt(idx);

 	if (idx >= __end_of_fixed_addresses) {
 		BUG();
 		return;
 	}

 	clear_pte_phys(address, prot);
 }

 static pmd_t * __init one_md_table_init(pud_t *pud)
 {
 	if (pud_none(*pud)) {
 		pmd_t *pmd;

 		pmd = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 		if (!pmd)
 			panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
 			      __func__, PAGE_SIZE, PAGE_SIZE);
 		pud_populate(&init_mm, pud, pmd);
 		BUG_ON(pmd != pmd_offset(pud, 0));
 	}

 	return pmd_offset(pud, 0);
 }

 static pte_t * __init one_page_table_init(pmd_t *pmd)
 {
 	if (pmd_none(*pmd)) {
 		pte_t *pte;

 		pte = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 		if (!pte)
 			panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
 			      __func__, PAGE_SIZE, PAGE_SIZE);
 		pmd_populate_kernel(&init_mm, pmd, pte);
 		BUG_ON(pte != pte_offset_kernel(pmd, 0));
 	}

 	return pte_offset_kernel(pmd, 0);
 }

 static pte_t * __init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
 					    unsigned long vaddr, pte_t *lastpte)
 {
 	return pte;
 }

 void __init page_table_range_init(unsigned long start, unsigned long end,
 					 pgd_t *pgd_base)
 {
 	pgd_t *pgd;
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte = NULL;
 	int i, j, k;
 	unsigned long vaddr;

 	vaddr = start;
 	i = pgd_index(vaddr);
 	j = pud_index(vaddr);
 	k = pmd_index(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 = one_md_table_init(pud);
 #ifndef __PAGETABLE_PMD_FOLDED
 			pmd += k;
 #endif
 			for (; (k < PTRS_PER_PMD) && (vaddr != end); pmd++, k++) {
 				pte = page_table_kmap_check(one_page_table_init(pmd),
 							    pmd, vaddr, pte);
 				vaddr += PMD_SIZE;
 			}
 			k = 0;
 		}
 		j = 0;
 	}
 }
 #endif	/* CONFIG_MMU */

 void __init allocate_pgdat(unsigned int nid)
 {
 	unsigned long start_pfn, end_pfn;

 	get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);

 #ifdef CONFIG_NUMA
 	NODE_DATA(nid) = memblock_alloc_try_nid(
 				sizeof(struct pglist_data),
 				SMP_CACHE_BYTES, MEMBLOCK_LOW_LIMIT,
 				MEMBLOCK_ALLOC_ACCESSIBLE, nid);
 	if (!NODE_DATA(nid))
 		panic("Can't allocate pgdat for node %d\n", nid);
 #endif

 	NODE_DATA(nid)->node_start_pfn = start_pfn;
 	NODE_DATA(nid)->node_spanned_pages = end_pfn - start_pfn;
 }

 static void __init do_init_bootmem(void)
 {
 	unsigned long start_pfn, end_pfn;
 	int i;

 	/* Add active regions with valid PFNs. */
 	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL)
 		__add_active_range(0, start_pfn, end_pfn);

 	/* All of system RAM sits in node 0 for the non-NUMA case */
 	allocate_pgdat(0);
 	node_set_online(0);

 	plat_mem_setup();

 	sparse_init();
 }

 static void __init early_reserve_mem(void)
 {
 	unsigned long start_pfn;
 	u32 zero_base = (u32)__MEMORY_START + (u32)PHYSICAL_OFFSET;
 	u32 start = zero_base + (u32)CONFIG_ZERO_PAGE_OFFSET;

 	/*
 	 * Partially used pages are not usable - thus
 	 * we are rounding upwards:
 	 */
 	start_pfn = PFN_UP(__pa(_end));

 	/*
 	 * Reserve the kernel text and Reserve the bootmem bitmap. We do
 	 * this in two steps (first step was init_bootmem()), because
 	 * this catches the (definitely buggy) case of us accidentally
 	 * initializing the bootmem allocator with an invalid RAM area.
 	 */
 	memblock_reserve(start, (PFN_PHYS(start_pfn) + PAGE_SIZE - 1) - start);

 	/*
 	 * Reserve physical pages below CONFIG_ZERO_PAGE_OFFSET.
 	 */
 	if (CONFIG_ZERO_PAGE_OFFSET != 0)
 		memblock_reserve(zero_base, CONFIG_ZERO_PAGE_OFFSET);

 	/*
 	 * Handle additional early reservations
 	 */
 	check_for_initrd();
 	reserve_crashkernel();
 }

 void __init paging_init(void)
 {
 	unsigned long max_zone_pfns[MAX_NR_ZONES];
 	unsigned long vaddr, end;

 	sh_mv.mv_mem_init();

 	early_reserve_mem();

 	/*
 	 * Once the early reservations are out of the way, give the
 	 * platforms a chance to kick out some memory.
 	 */
 	if (sh_mv.mv_mem_reserve)
 		sh_mv.mv_mem_reserve();

 	memblock_enforce_memory_limit(memory_limit);
 	memblock_allow_resize();

 	memblock_dump_all();

 	/*
 	 * Determine low and high memory ranges:
 	 */
 	max_low_pfn = max_pfn = memblock_end_of_DRAM() >> PAGE_SHIFT;
 	min_low_pfn = __MEMORY_START >> PAGE_SHIFT;
 	set_max_mapnr(max_low_pfn - min_low_pfn);

 	nodes_clear(node_online_map);

 	memory_start = (unsigned long)__va(__MEMORY_START);
 	memory_end = memory_start + (memory_limit ?: memblock_phys_mem_size());

 	uncached_init();
 	pmb_init();
 	do_init_bootmem();
 	ioremap_fixed_init();

 	/* We don't need to map the kernel through the TLB, as
 	 * it is permanatly mapped using P1. So clear the
 	 * entire pgd. */
 	memset(swapper_pg_dir, 0, sizeof(swapper_pg_dir));

 	/* Set an initial value for the MMU.TTB so we don't have to
 	 * check for a null value. */
 	set_TTB(swapper_pg_dir);

 	/*
 	 * Populate the relevant portions of swapper_pg_dir so that
 	 * we can use the fixmap entries without calling kmalloc.
 	 * pte's will be filled in by __set_fixmap().
 	 */
 	vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 	end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
 	page_table_range_init(vaddr, end, swapper_pg_dir);

 	kmap_coherent_init();

 	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
 	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
 	free_area_init(max_zone_pfns);
 }

 unsigned int mem_init_done = 0;

 void __init mem_init(void)
 {
 	pg_data_t *pgdat;

 	high_memory = NULL;
 	for_each_online_pgdat(pgdat)
 		high_memory = max_t(void *, high_memory,
 				    __va(pgdat_end_pfn(pgdat) << PAGE_SHIFT));

 	memblock_free_all();

 	/* Set this up early, so we can take care of the zero page */
 	cpu_cache_init();

 	/* clear the zero-page */
 	memset(empty_zero_page, 0, PAGE_SIZE);
 	__flush_wback_region(empty_zero_page, PAGE_SIZE);

 	vsyscall_init();

 	pr_info("virtual kernel memory layout:\n"
 		"    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 		"    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 		"    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB) (cached)\n"
 #ifdef CONFIG_UNCACHED_MAPPING
 		"            : 0x%08lx - 0x%08lx   (%4ld MB) (uncached)\n"
 #endif
 		"      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 		"      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 		"      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",
 		FIXADDR_START, FIXADDR_TOP,
 		(FIXADDR_TOP - FIXADDR_START) >> 10,

 		(unsigned long)VMALLOC_START, VMALLOC_END,
 		(VMALLOC_END - VMALLOC_START) >> 20,

 		(unsigned long)memory_start, (unsigned long)high_memory,
 		((unsigned long)high_memory - (unsigned long)memory_start) >> 20,

 #ifdef CONFIG_UNCACHED_MAPPING
 		uncached_start, uncached_end, uncached_size >> 20,
 #endif

 		(unsigned long)&__init_begin, (unsigned long)&__init_end,
 		((unsigned long)&__init_end -
 		 (unsigned long)&__init_begin) >> 10,

 		(unsigned long)&_etext, (unsigned long)&_edata,
 		((unsigned long)&_edata - (unsigned long)&_etext) >> 10,

 		(unsigned long)&_text, (unsigned long)&_etext,
 		((unsigned long)&_etext - (unsigned long)&_text) >> 10);

 	mem_init_done = 1;
 }

 #ifdef CONFIG_MEMORY_HOTPLUG
 int arch_add_memory(int nid, u64 start, u64 size,
 		    struct mhp_params *params)
 {
 	unsigned long start_pfn = PFN_DOWN(start);
 	unsigned long nr_pages = size >> PAGE_SHIFT;
 	int ret;

 	if (WARN_ON_ONCE(params->pgprot.pgprot != PAGE_KERNEL.pgprot))
 		return -EINVAL;

 	/* We only have ZONE_NORMAL, so this is easy.. */
 	ret = __add_pages(nid, start_pfn, nr_pages, params);
 	if (unlikely(ret))
 		printk("%s: Failed, __add_pages() == %d\n", __func__, ret);

 	return ret;
 }

 void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
 {
 	unsigned long start_pfn = PFN_DOWN(start);
 	unsigned long nr_pages = size >> PAGE_SHIFT;

 	__remove_pages(start_pfn, nr_pages, altmap);
 }
 #endif /* CONFIG_MEMORY_HOTPLUG */
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* linux/arch/sh/mm/init.c
	*
	* Copyright (C) 1999 Niibe Yutaka
	* Copyright (C) 2002 - 2011 Paul Mundt
	*
	* Based on linux/arch/i386/mm/init.c:
	* Copyright (C) 1995 Linus Torvalds
	*/
	#include <linux/mm.h>
	#include <linux/swap.h>
	#include <linux/init.h>
	#include <linux/gfp.h>
	#include <linux/memblock.h>
	#include <linux/proc_fs.h>
	#include <linux/pagemap.h>
	#include <linux/percpu.h>
	#include <linux/io.h>
	#include <linux/dma-mapping.h>
	#include <linux/export.h>
	#include <asm/mmu_context.h>
	#include <asm/mmzone.h>
	#include <asm/kexec.h>
	#include <asm/tlb.h>
	#include <asm/cacheflush.h>
	#include <asm/sections.h>
	#include <asm/setup.h>
	#include <asm/cache.h>
	#include <asm/pgalloc.h>
	#include <linux/sizes.h>
	#include "ioremap.h"

	pgd_t swapper_pg_dir[PTRS_PER_PGD];

	void __init generic_mem_init(void)
	{
	memblock_add(__MEMORY_START, __MEMORY_SIZE);
	}

	void __init __weak plat_mem_setup(void)
	{
	/* Nothing to see here, move along. */
	}

	#ifdef CONFIG_MMU
	static pte_t *__get_pte_phys(unsigned long addr)
	{
	pgd_t *pgd;
	p4d_t *p4d;
	pud_t *pud;
	pmd_t *pmd;

	pgd = pgd_offset_k(addr);
	if (pgd_none(*pgd)) {
	pgd_ERROR(*pgd);
	return NULL;
	}

	p4d = p4d_alloc(NULL, pgd, addr);
	if (unlikely(!p4d)) {
	p4d_ERROR(*p4d);
	return NULL;
	}

	pud = pud_alloc(NULL, p4d, addr);
	if (unlikely(!pud)) {
	pud_ERROR(*pud);
	return NULL;
	}

	pmd = pmd_alloc(NULL, pud, addr);
	if (unlikely(!pmd)) {
	pmd_ERROR(*pmd);
	return NULL;
	}

	return pte_offset_kernel(pmd, addr);
	}

	static void set_pte_phys(unsigned long addr, unsigned long phys, pgprot_t prot)
	{
	pte_t *pte;

	pte = __get_pte_phys(addr);
	if (!pte_none(*pte)) {
	pte_ERROR(*pte);
	return;
	}

	set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, prot));
	local_flush_tlb_one(get_asid(), addr);

	if (pgprot_val(prot) & _PAGE_WIRED)
	tlb_wire_entry(NULL, addr, *pte);
	}

	static void clear_pte_phys(unsigned long addr, pgprot_t prot)
	{
	pte_t *pte;

	pte = __get_pte_phys(addr);

	if (pgprot_val(prot) & _PAGE_WIRED)
	tlb_unwire_entry();

	set_pte(pte, pfn_pte(0, __pgprot(0)));
	local_flush_tlb_one(get_asid(), addr);
	}

	void __set_fixmap(enum fixed_addresses idx, unsigned long phys, pgprot_t prot)
	{
	unsigned long address = __fix_to_virt(idx);

	if (idx >= __end_of_fixed_addresses) {
	BUG();
	return;
	}

	set_pte_phys(address, phys, prot);
	}

	void __clear_fixmap(enum fixed_addresses idx, pgprot_t prot)
	{
	unsigned long address = __fix_to_virt(idx);

	if (idx >= __end_of_fixed_addresses) {
	BUG();
	return;
	}

	clear_pte_phys(address, prot);
	}

	static pmd_t * __init one_md_table_init(pud_t *pud)
	{
	if (pud_none(*pud)) {
	pmd_t *pmd;

	pmd = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
	if (!pmd)
	panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
	__func__, PAGE_SIZE, PAGE_SIZE);
	pud_populate(&init_mm, pud, pmd);
	BUG_ON(pmd != pmd_offset(pud, 0));
	}

	return pmd_offset(pud, 0);
	}

	static pte_t * __init one_page_table_init(pmd_t *pmd)
	{
	if (pmd_none(*pmd)) {
	pte_t *pte;

	pte = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
	if (!pte)
	panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
	__func__, PAGE_SIZE, PAGE_SIZE);
	pmd_populate_kernel(&init_mm, pmd, pte);
	BUG_ON(pte != pte_offset_kernel(pmd, 0));
	}

	return pte_offset_kernel(pmd, 0);
	}

	static pte_t * __init page_table_kmap_check(pte_t pte, pmd_t pmd,
	unsigned long vaddr, pte_t *lastpte)
	{
	return pte;
	}

	void __init page_table_range_init(unsigned long start, unsigned long end,
	pgd_t *pgd_base)
	{
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte = NULL;
	int i, j, k;
	unsigned long vaddr;

	vaddr = start;
	i = pgd_index(vaddr);
	j = pud_index(vaddr);
	k = pmd_index(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 = one_md_table_init(pud);
	#ifndef __PAGETABLE_PMD_FOLDED
	pmd += k;
	#endif
	for (; (k < PTRS_PER_PMD) && (vaddr != end); pmd++, k++) {
	pte = page_table_kmap_check(one_page_table_init(pmd),
	pmd, vaddr, pte);
	vaddr += PMD_SIZE;
	}
	k = 0;
	}
	j = 0;
	}
	}
	#endif /* CONFIG_MMU */

	void __init allocate_pgdat(unsigned int nid)
	{
	unsigned long start_pfn, end_pfn;

	get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);

	#ifdef CONFIG_NUMA
	NODE_DATA(nid) = memblock_alloc_try_nid(
	sizeof(struct pglist_data),
	SMP_CACHE_BYTES, MEMBLOCK_LOW_LIMIT,
	MEMBLOCK_ALLOC_ACCESSIBLE, nid);
	if (!NODE_DATA(nid))
	panic("Can't allocate pgdat for node %d\n", nid);
	#endif

	NODE_DATA(nid)->node_start_pfn = start_pfn;
	NODE_DATA(nid)->node_spanned_pages = end_pfn - start_pfn;
	}

	static void __init do_init_bootmem(void)
	{
	unsigned long start_pfn, end_pfn;
	int i;

	/* Add active regions with valid PFNs. */
	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL)
	__add_active_range(0, start_pfn, end_pfn);

	/* All of system RAM sits in node 0 for the non-NUMA case */
	allocate_pgdat(0);
	node_set_online(0);

	plat_mem_setup();

	sparse_init();
	}

	static void __init early_reserve_mem(void)
	{
	unsigned long start_pfn;
	u32 zero_base = (u32)__MEMORY_START + (u32)PHYSICAL_OFFSET;
	u32 start = zero_base + (u32)CONFIG_ZERO_PAGE_OFFSET;

	/*
	* Partially used pages are not usable - thus
	* we are rounding upwards:
	*/
	start_pfn = PFN_UP(__pa(_end));

	/*
	* Reserve the kernel text and Reserve the bootmem bitmap. We do
	* this in two steps (first step was init_bootmem()), because
	* this catches the (definitely buggy) case of us accidentally
	* initializing the bootmem allocator with an invalid RAM area.
	*/
	memblock_reserve(start, (PFN_PHYS(start_pfn) + PAGE_SIZE - 1) - start);

	/*
	* Reserve physical pages below CONFIG_ZERO_PAGE_OFFSET.
	*/
	if (CONFIG_ZERO_PAGE_OFFSET != 0)
	memblock_reserve(zero_base, CONFIG_ZERO_PAGE_OFFSET);

	/*
	* Handle additional early reservations
	*/
	check_for_initrd();
	reserve_crashkernel();
	}

	void __init paging_init(void)
	{
	unsigned long max_zone_pfns[MAX_NR_ZONES];
	unsigned long vaddr, end;

	sh_mv.mv_mem_init();

	early_reserve_mem();

	/*
	* Once the early reservations are out of the way, give the
	* platforms a chance to kick out some memory.
	*/
	if (sh_mv.mv_mem_reserve)
	sh_mv.mv_mem_reserve();

	memblock_enforce_memory_limit(memory_limit);
	memblock_allow_resize();

	memblock_dump_all();

	/*
	* Determine low and high memory ranges:
	*/
	max_low_pfn = max_pfn = memblock_end_of_DRAM() >> PAGE_SHIFT;
	min_low_pfn = __MEMORY_START >> PAGE_SHIFT;
	set_max_mapnr(max_low_pfn - min_low_pfn);

	nodes_clear(node_online_map);

	memory_start = (unsigned long)__va(__MEMORY_START);
	memory_end = memory_start + (memory_limit ?: memblock_phys_mem_size());

	uncached_init();
	pmb_init();
	do_init_bootmem();
	ioremap_fixed_init();

	/* We don't need to map the kernel through the TLB, as
	* it is permanatly mapped using P1. So clear the
	* entire pgd. */
	memset(swapper_pg_dir, 0, sizeof(swapper_pg_dir));

	/* Set an initial value for the MMU.TTB so we don't have to
	* check for a null value. */
	set_TTB(swapper_pg_dir);

	/*
	* Populate the relevant portions of swapper_pg_dir so that
	* we can use the fixmap entries without calling kmalloc.
	* pte's will be filled in by __set_fixmap().
	*/
	vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
	end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
	page_table_range_init(vaddr, end, swapper_pg_dir);

	kmap_coherent_init();

	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
	free_area_init(max_zone_pfns);
	}

	unsigned int mem_init_done = 0;

	void __init mem_init(void)
	{
	pg_data_t *pgdat;

	high_memory = NULL;
	for_each_online_pgdat(pgdat)
	high_memory = max_t(void *, high_memory,
	__va(pgdat_end_pfn(pgdat) << PAGE_SHIFT));

	memblock_free_all();

	/* Set this up early, so we can take care of the zero page */
	cpu_cache_init();

	/* clear the zero-page */
	memset(empty_zero_page, 0, PAGE_SIZE);
	__flush_wback_region(empty_zero_page, PAGE_SIZE);

	vsyscall_init();

	pr_info("virtual kernel memory layout:\n"
	" fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
	" vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n"
	" lowmem : 0x%08lx - 0x%08lx (%4ld MB) (cached)\n"
	#ifdef CONFIG_UNCACHED_MAPPING
	" : 0x%08lx - 0x%08lx (%4ld MB) (uncached)\n"
	#endif
	" .init : 0x%08lx - 0x%08lx (%4ld kB)\n"
	" .data : 0x%08lx - 0x%08lx (%4ld kB)\n"
	" .text : 0x%08lx - 0x%08lx (%4ld kB)\n",
	FIXADDR_START, FIXADDR_TOP,
	(FIXADDR_TOP - FIXADDR_START) >> 10,

	(unsigned long)VMALLOC_START, VMALLOC_END,
	(VMALLOC_END - VMALLOC_START) >> 20,

	(unsigned long)memory_start, (unsigned long)high_memory,
	((unsigned long)high_memory - (unsigned long)memory_start) >> 20,

	#ifdef CONFIG_UNCACHED_MAPPING
	uncached_start, uncached_end, uncached_size >> 20,
	#endif

	(unsigned long)&__init_begin, (unsigned long)&__init_end,
	((unsigned long)&__init_end -
	(unsigned long)&__init_begin) >> 10,

	(unsigned long)&_etext, (unsigned long)&_edata,
	((unsigned long)&_edata - (unsigned long)&_etext) >> 10,

	(unsigned long)&_text, (unsigned long)&_etext,
	((unsigned long)&_etext - (unsigned long)&_text) >> 10);

	mem_init_done = 1;
	}

	#ifdef CONFIG_MEMORY_HOTPLUG
	int arch_add_memory(int nid, u64 start, u64 size,
	struct mhp_params *params)
	{
	unsigned long start_pfn = PFN_DOWN(start);
	unsigned long nr_pages = size >> PAGE_SHIFT;
	int ret;

	if (WARN_ON_ONCE(params->pgprot.pgprot != PAGE_KERNEL.pgprot))
	return -EINVAL;

	/* We only have ZONE_NORMAL, so this is easy.. */
	ret = __add_pages(nid, start_pfn, nr_pages, params);
	if (unlikely(ret))
	printk("%s: Failed, __add_pages() == %d\n", __func__, ret);

	return ret;
	}

	void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
	{
	unsigned long start_pfn = PFN_DOWN(start);
	unsigned long nr_pages = size >> PAGE_SHIFT;

	__remove_pages(start_pfn, nr_pages, altmap);
	}
	#endif /* CONFIG_MEMORY_HOTPLUG */