1. 根目录:
2. arch
3. mn10300
4. mm
5. init.c

/* MN10300 Memory management initialisation
 *
 * Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Modified by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */
#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/fs.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/initrd.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/bootmem.h>
#include <linux/gfp.h>

#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/dma.h>
#include <asm/tlb.h>
#include <asm/sections.h>

unsigned long highstart_pfn, highend_pfn;

#ifdef CONFIG_MN10300_HAS_ATOMIC_OPS_UNIT
static struct vm_struct user_iomap_vm;
#endif

/*
 * set up paging
 */
void __init paging_init(void)
{
	unsigned long zones_size[MAX_NR_ZONES] = {0,};
	pte_t *ppte;
	int loop;

	/* main kernel space -> RAM mapping is handled as 1:1 transparent by
	 * the MMU */
	memset(swapper_pg_dir, 0, sizeof(swapper_pg_dir));
	memset(kernel_vmalloc_ptes, 0, sizeof(kernel_vmalloc_ptes));

	/* load the VMALLOC area PTE table addresses into the kernel PGD */
	ppte = kernel_vmalloc_ptes;
	for (loop = VMALLOC_START / (PAGE_SIZE * PTRS_PER_PTE);
	     loop < VMALLOC_END / (PAGE_SIZE * PTRS_PER_PTE);
	     loop++
	     ) {
		set_pgd(swapper_pg_dir + loop, __pgd(__pa(ppte) | _PAGE_TABLE));
		ppte += PAGE_SIZE / sizeof(pte_t);
	}

	/* declare the sizes of the RAM zones (only use the normal zone) */
	zones_size[ZONE_NORMAL] =
		contig_page_data.bdata->node_low_pfn -
		contig_page_data.bdata->node_min_pfn;

	/* pass the memory from the bootmem allocator to the main allocator */
	free_area_init(zones_size);

#ifdef CONFIG_MN10300_HAS_ATOMIC_OPS_UNIT
	/* The Atomic Operation Unit registers need to be mapped to userspace
	 * for all processes.  The following uses vm_area_register_early() to
	 * reserve the first page of the vmalloc area and sets the pte for that
	 * page.
	 *
	 * glibc hardcodes this virtual mapping, so we're pretty much stuck with
	 * it from now on.
	 */
	user_iomap_vm.flags = VM_USERMAP;
	user_iomap_vm.size = 1 << PAGE_SHIFT;
	vm_area_register_early(&user_iomap_vm, PAGE_SIZE);
	ppte = kernel_vmalloc_ptes;
	set_pte(ppte, pfn_pte(USER_ATOMIC_OPS_PAGE_ADDR >> PAGE_SHIFT,
			      PAGE_USERIO));
#endif

	local_flush_tlb_all();
}

/*
 * transfer all the memory from the bootmem allocator to the runtime allocator
 */
void __init mem_init(void)
{
	BUG_ON(!mem_map);

#define START_PFN	(contig_page_data.bdata->node_min_pfn)
#define MAX_LOW_PFN	(contig_page_data.bdata->node_low_pfn)

	max_mapnr = MAX_LOW_PFN - START_PFN;
	high_memory = (void *) __va(MAX_LOW_PFN * PAGE_SIZE);

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

	/* this will put all low memory onto the freelists */
	free_all_bootmem();

	mem_init_print_info(NULL);
}

/*
 * recycle memory containing stuff only required for initialisation
 */
void free_initmem(void)
{
	free_initmem_default(POISON_FREE_INITMEM);
}

/*
 * dispose of the memory on which the initial ramdisk resided
 */
#ifdef CONFIG_BLK_DEV_INITRD
void free_initrd_mem(unsigned long start, unsigned long end)
{
	free_reserved_area((void *)start, (void *)end, POISON_FREE_INITMEM,
			   "initrd");
}
#endif