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kernel/linux-imx6_3.14.28/arch/avr32/mm/init.c 2.97 KB
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  /*
   * Copyright (C) 2004-2006 Atmel Corporation
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  
  #include <linux/kernel.h>
  #include <linux/gfp.h>
  #include <linux/mm.h>
  #include <linux/swap.h>
  #include <linux/init.h>
  #include <linux/mmzone.h>
  #include <linux/module.h>
  #include <linux/bootmem.h>
  #include <linux/pagemap.h>
  #include <linux/nodemask.h>
  
  #include <asm/page.h>
  #include <asm/mmu_context.h>
  #include <asm/tlb.h>
  #include <asm/io.h>
  #include <asm/dma.h>
  #include <asm/setup.h>
  #include <asm/sections.h>
  
  pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_data;
  
  struct page *empty_zero_page;
  EXPORT_SYMBOL(empty_zero_page);
  
  /*
   * Cache of MMU context last used.
   */
  unsigned long mmu_context_cache = NO_CONTEXT;
  
  /*
   * paging_init() sets up the page tables
   *
   * This routine also unmaps the page at virtual kernel address 0, so
   * that we can trap those pesky NULL-reference errors in the kernel.
   */
  void __init paging_init(void)
  {
  	extern unsigned long _evba;
  	void *zero_page;
  	int nid;
  
  	/*
  	 * Make sure we can handle exceptions before enabling
  	 * paging. Not that we should ever _get_ any exceptions this
  	 * early, but you never know...
  	 */
  	printk("Exception vectors start at %p
  ", &_evba);
  	sysreg_write(EVBA, (unsigned long)&_evba);
  
  	/*
  	 * Since we are ready to handle exceptions now, we should let
  	 * the CPU generate them...
  	 */
  	__asm__ __volatile__ ("csrf %0" : : "i"(SR_EM_BIT));
  
  	/*
  	 * Allocate the zero page. The allocator will panic if it
  	 * can't satisfy the request, so no need to check.
  	 */
  	zero_page = alloc_bootmem_low_pages_node(NODE_DATA(0),
  						 PAGE_SIZE);
  
  	sysreg_write(PTBR, (unsigned long)swapper_pg_dir);
  	enable_mmu();
  	printk ("CPU: Paging enabled
  ");
  
  	for_each_online_node(nid) {
  		pg_data_t *pgdat = NODE_DATA(nid);
  		unsigned long zones_size[MAX_NR_ZONES];
  		unsigned long low, start_pfn;
  
  		start_pfn = pgdat->bdata->node_min_pfn;
  		low = pgdat->bdata->node_low_pfn;
  
  		memset(zones_size, 0, sizeof(zones_size));
  		zones_size[ZONE_NORMAL] = low - start_pfn;
  
  		printk("Node %u: start_pfn = 0x%lx, low = 0x%lx
  ",
  		       nid, start_pfn, low);
  
  		free_area_init_node(nid, zones_size, start_pfn, NULL);
  
  		printk("Node %u: mem_map starts at %p
  ",
  		       pgdat->node_id, pgdat->node_mem_map);
  	}
  
  	mem_map = NODE_DATA(0)->node_mem_map;
  
  	empty_zero_page = virt_to_page(zero_page);
  	flush_dcache_page(empty_zero_page);
  }
  
  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));
  
  	set_max_mapnr(MAP_NR(high_memory));
  	free_all_bootmem();
  	mem_init_print_info(NULL);
  }
  
  void free_initmem(void)
  {
  	free_initmem_default(-1);
  }
  
  #ifdef CONFIG_BLK_DEV_INITRD
  void free_initrd_mem(unsigned long start, unsigned long end)
  {
  	free_reserved_area((void *)start, (void *)end, -1, "initrd");
  }
  #endif