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