245 lines
6.0 KiB
C
245 lines
6.0 KiB
C
/*
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* PowerPC version
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* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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*
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* Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
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* and Cort Dougan (PReP) (cort@cs.nmt.edu)
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* Copyright (C) 1996 Paul Mackerras
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* PPC44x/36-bit changes by Matt Porter (mporter@mvista.com)
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*
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* Derived from "arch/i386/mm/init.c"
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* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
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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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*/
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/mm.h>
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#include <linux/stddef.h>
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#include <linux/init.h>
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#include <linux/bootmem.h>
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#include <linux/highmem.h>
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#include <linux/initrd.h>
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#include <linux/pagemap.h>
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#include <linux/lmb.h>
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#include <asm/pgalloc.h>
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#include <asm/prom.h>
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#include <asm/io.h>
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#include <asm/pgtable.h>
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#include <asm/mmu.h>
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#include <asm/smp.h>
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#include <asm/machdep.h>
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#include <asm/btext.h>
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#include <asm/tlb.h>
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#include <asm/sections.h>
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#include <asm/system.h>
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#include "mmu_decl.h"
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#if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
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/* The ammount of lowmem must be within 0xF0000000 - KERNELBASE. */
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#if (CONFIG_LOWMEM_SIZE > (0xF0000000 - PAGE_OFFSET))
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#error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_START_KERNEL"
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#endif
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#endif
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#define MAX_LOW_MEM CONFIG_LOWMEM_SIZE
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phys_addr_t total_memory;
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phys_addr_t total_lowmem;
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phys_addr_t memstart_addr = (phys_addr_t)~0ull;
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EXPORT_SYMBOL(memstart_addr);
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phys_addr_t kernstart_addr;
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EXPORT_SYMBOL(kernstart_addr);
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phys_addr_t lowmem_end_addr;
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int boot_mapsize;
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#ifdef CONFIG_PPC_PMAC
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unsigned long agp_special_page;
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EXPORT_SYMBOL(agp_special_page);
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#endif
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void MMU_init(void);
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/* XXX should be in current.h -- paulus */
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extern struct task_struct *current_set[NR_CPUS];
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/*
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* this tells the system to map all of ram with the segregs
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* (i.e. page tables) instead of the bats.
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* -- Cort
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*/
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int __map_without_bats;
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int __map_without_ltlbs;
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/* max amount of low RAM to map in */
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unsigned long __max_low_memory = MAX_LOW_MEM;
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/*
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* address of the limit of what is accessible with initial MMU setup -
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* 256MB usually, but only 16MB on 601.
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*/
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phys_addr_t __initial_memory_limit_addr = (phys_addr_t)0x10000000;
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/*
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* Check for command-line options that affect what MMU_init will do.
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*/
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void MMU_setup(void)
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{
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/* Check for nobats option (used in mapin_ram). */
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if (strstr(cmd_line, "nobats")) {
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__map_without_bats = 1;
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}
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if (strstr(cmd_line, "noltlbs")) {
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__map_without_ltlbs = 1;
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}
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#ifdef CONFIG_DEBUG_PAGEALLOC
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__map_without_bats = 1;
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__map_without_ltlbs = 1;
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#endif
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}
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/*
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* MMU_init sets up the basic memory mappings for the kernel,
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* including both RAM and possibly some I/O regions,
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* and sets up the page tables and the MMU hardware ready to go.
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*/
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void __init MMU_init(void)
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{
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if (ppc_md.progress)
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ppc_md.progress("MMU:enter", 0x111);
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/* 601 can only access 16MB at the moment */
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if (PVR_VER(mfspr(SPRN_PVR)) == 1)
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__initial_memory_limit_addr = 0x01000000;
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/* 8xx can only access 8MB at the moment */
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if (PVR_VER(mfspr(SPRN_PVR)) == 0x50)
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__initial_memory_limit_addr = 0x00800000;
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/* parse args from command line */
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MMU_setup();
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if (lmb.memory.cnt > 1) {
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lmb.memory.cnt = 1;
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lmb_analyze();
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printk(KERN_WARNING "Only using first contiguous memory region");
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}
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total_lowmem = total_memory = lmb_end_of_DRAM() - memstart_addr;
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lowmem_end_addr = memstart_addr + total_lowmem;
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#ifdef CONFIG_FSL_BOOKE
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/* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
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* entries, so we need to adjust lowmem to match the amount we can map
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* in the fixed entries */
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adjust_total_lowmem();
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#endif /* CONFIG_FSL_BOOKE */
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if (total_lowmem > __max_low_memory) {
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total_lowmem = __max_low_memory;
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lowmem_end_addr = memstart_addr + total_lowmem;
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#ifndef CONFIG_HIGHMEM
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total_memory = total_lowmem;
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lmb_enforce_memory_limit(lowmem_end_addr);
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lmb_analyze();
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#endif /* CONFIG_HIGHMEM */
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}
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/* Initialize the MMU hardware */
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if (ppc_md.progress)
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ppc_md.progress("MMU:hw init", 0x300);
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MMU_init_hw();
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/* Map in all of RAM starting at KERNELBASE */
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if (ppc_md.progress)
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ppc_md.progress("MMU:mapin", 0x301);
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mapin_ram();
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/* Initialize early top-down ioremap allocator */
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ioremap_bot = IOREMAP_TOP;
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/* Map in I/O resources */
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if (ppc_md.progress)
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ppc_md.progress("MMU:setio", 0x302);
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if (ppc_md.progress)
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ppc_md.progress("MMU:exit", 0x211);
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/* From now on, btext is no longer BAT mapped if it was at all */
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#ifdef CONFIG_BOOTX_TEXT
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btext_unmap();
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#endif
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}
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/* This is only called until mem_init is done. */
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void __init *early_get_page(void)
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{
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void *p;
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if (init_bootmem_done) {
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p = alloc_bootmem_pages(PAGE_SIZE);
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} else {
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p = __va(lmb_alloc_base(PAGE_SIZE, PAGE_SIZE,
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__initial_memory_limit_addr));
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}
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return p;
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}
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/* Free up now-unused memory */
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static void free_sec(unsigned long start, unsigned long end, const char *name)
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{
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unsigned long cnt = 0;
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while (start < end) {
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ClearPageReserved(virt_to_page(start));
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init_page_count(virt_to_page(start));
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free_page(start);
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cnt++;
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start += PAGE_SIZE;
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}
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if (cnt) {
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printk(" %ldk %s", cnt << (PAGE_SHIFT - 10), name);
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totalram_pages += cnt;
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}
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}
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void free_initmem(void)
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{
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#define FREESEC(TYPE) \
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free_sec((unsigned long)(&__ ## TYPE ## _begin), \
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(unsigned long)(&__ ## TYPE ## _end), \
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#TYPE);
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printk ("Freeing unused kernel memory:");
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FREESEC(init);
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printk("\n");
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ppc_md.progress = NULL;
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#undef FREESEC
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}
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#ifdef CONFIG_BLK_DEV_INITRD
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void free_initrd_mem(unsigned long start, unsigned long end)
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{
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if (start < end)
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printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
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for (; start < end; start += PAGE_SIZE) {
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ClearPageReserved(virt_to_page(start));
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init_page_count(virt_to_page(start));
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free_page(start);
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totalram_pages++;
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}
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}
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#endif
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