init.c
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/* init.c: memory initialisation for FRV
*
* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
* Written 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 License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Derived from:
* - linux/arch/m68knommu/mm/init.c
* - Copyright (C) 1998 D. Jeff Dionne <jeff@lineo.ca>, Kenneth Albanowski <kjahds@kjahds.com>,
* - Copyright (C) 2000 Lineo, Inc. (www.lineo.com)
* - linux/arch/m68k/mm/init.c
* - Copyright (C) 1995 Hamish Macdonald
*/
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/pagemap.h>
#include <linux/gfp.h>
#include <linux/swap.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/bootmem.h>
#include <linux/highmem.h>
#include <linux/module.h>
#include <asm/setup.h>
#include <asm/segment.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/mmu_context.h>
#include <asm/virtconvert.h>
#include <asm/sections.h>
#include <asm/tlb.h>
#undef DEBUG
/*
* BAD_PAGE is the page that is used for page faults when linux
* is out-of-memory. Older versions of linux just did a
* do_exit(), but using this instead means there is less risk
* for a process dying in kernel mode, possibly leaving a inode
* unused etc..
*
* BAD_PAGETABLE is the accompanying page-table: it is initialized
* to point to BAD_PAGE entries.
*
* ZERO_PAGE is a special page that is used for zero-initialized
* data and COW.
*/
static unsigned long empty_bad_page_table;
static unsigned long empty_bad_page;
unsigned long empty_zero_page;
EXPORT_SYMBOL(empty_zero_page);
/*****************************************************************************/
/*
* paging_init() continues the virtual memory environment setup which
* was begun by the code in arch/head.S.
* The parameters are pointers to where to stick the starting and ending
* addresses of available kernel virtual memory.
*/
void __init paging_init(void)
{
unsigned long zones_size[MAX_NR_ZONES] = {0, };
/* allocate some pages for kernel housekeeping tasks */
empty_bad_page_table = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
empty_bad_page = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
empty_zero_page = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
memset((void *) empty_zero_page, 0, PAGE_SIZE);
#ifdef CONFIG_HIGHMEM
if (get_num_physpages() - num_mappedpages) {
pgd_t *pge;
pud_t *pue;
pmd_t *pme;
pkmap_page_table = alloc_bootmem_pages(PAGE_SIZE);
pge = swapper_pg_dir + pgd_index_k(PKMAP_BASE);
pue = pud_offset(pge, PKMAP_BASE);
pme = pmd_offset(pue, PKMAP_BASE);
__set_pmd(pme, virt_to_phys(pkmap_page_table) | _PAGE_TABLE);
}
#endif
/* distribute the allocatable pages across the various zones and pass them to the allocator
*/
zones_size[ZONE_NORMAL] = max_low_pfn - min_low_pfn;
#ifdef CONFIG_HIGHMEM
zones_size[ZONE_HIGHMEM] = get_num_physpages() - num_mappedpages;
#endif
free_area_init(zones_size);
#ifdef CONFIG_MMU
/* initialise init's MMU context */
init_new_context(&init_task, &init_mm);
#endif
} /* end paging_init() */
/*****************************************************************************/
/*
*
*/
void __init mem_init(void)
{
unsigned long code_size = _etext - _stext;
/* this will put all low memory onto the freelists */
free_all_bootmem();
#if defined(CONFIG_MMU) && defined(CONFIG_HIGHMEM)
{
unsigned long pfn;
for (pfn = get_num_physpages() - 1;
pfn >= num_mappedpages; pfn--)
free_highmem_page(&mem_map[pfn]);
}
#endif
mem_init_print_info(NULL);
if (rom_length > 0 && rom_length >= code_size)
printk("Memory available: %luKiB/%luKiB ROM\n",
(rom_length - code_size) >> 10, rom_length >> 10);
} /* end mem_init() */
/*****************************************************************************/
/*
* free the memory that was only required for initialisation
*/
void free_initmem(void)
{
#if defined(CONFIG_RAMKERNEL) && !defined(CONFIG_PROTECT_KERNEL)
free_initmem_default(-1);
#endif
} /* end free_initmem() */
/*****************************************************************************/
/*
* free the initial ramdisk memory
*/
#ifdef CONFIG_BLK_DEV_INITRD
void __init free_initrd_mem(unsigned long start, unsigned long end)
{
free_reserved_area((void *)start, (void *)end, -1, "initrd");
} /* end free_initrd_mem() */
#endif