init.c

内核linux2.4.20,可跟rtlinux3.2打补丁 组成实时linux系统,编译内核

/*
 *  linux/arch/cris/mm/init.c
 *
 *  Copyright (C) 1995  Linus Torvalds
 *  Copyright (C) 2000,2001  Axis Communications AB
 *
 *  Authors:  Bjorn Wesen ([e-mail])
 *
 *  $Log: init.c,v $
 *  Revision 1.31  2001/11/13 16:22:00  bjornw
 *  Skip calculating totalram and sharedram in si_meminfo
 *
 *  Revision 1.30  2001/11/12 19:02:10  pkj
 *  Fixed compiler warnings.
 *
 *  Revision 1.29  2001/07/25 16:09:50  bjornw
 *  val->sharedram will stay 0
 *
 *  Revision 1.28  2001/06/28 16:30:17  bjornw
 *  Oops. This needs to wait until 2.4.6 is merged
 *
 *  Revision 1.27  2001/06/28 14:04:07  bjornw
 *  Fill in sharedram
 *
 *  Revision 1.26  2001/06/18 06:36:02  hp
 *  Enable free_initmem of __init-type pages
 *
 *  Revision 1.25  2001/06/13 00:02:23  bjornw
 *  Use a separate variable to store the current pgd to avoid races in schedule
 *
 *  Revision 1.24  2001/05/15 00:52:20  hp
 *  Only map segment 0xa as seg if CONFIG_JULIETTE
 *
 *  Revision 1.23  2001/04/04 14:35:40  bjornw
 *  * Removed get_pte_slow and friends (2.4.3 change)
 *  * Removed bad_pmd handling (2.4.3 change)
 *
 *  Revision 1.22  2001/04/04 13:38:04  matsfg
 *  Moved ioremap to a separate function instead
 *
 *  Revision 1.21  2001/03/27 09:28:33  bjornw
 *  ioremap used too early - lets try it in mem_init instead
 *
 *  Revision 1.20  2001/03/23 07:39:21  starvik
 *  Corrected according to review remarks
 *
 *  Revision 1.19  2001/03/15 14:25:17  bjornw
 *  More general shadow registers and ioremaped addresses for external I/O
 *
 *  Revision 1.18  2001/02/23 12:46:44  bjornw
 *  * 0xc was not CSE1; 0x8 is, same as uncached flash, so we move the uncached
 *    flash during CRIS_LOW_MAP from 0xe to 0x8 so both the flash and the I/O
 *    is mapped straight over (for !CRIS_LOW_MAP the uncached flash is still 0xe)
 *
 *  Revision 1.17  2001/02/22 15:05:21  bjornw
 *  Map 0x9 straight over during LOW_MAP to allow for memory mapped LEDs
 *
 *  Revision 1.16  2001/02/22 15:02:35  bjornw
 *  Map 0xc straight over during LOW_MAP to allow for memory mapped I/O
 *
 *  Revision 1.15  2001/01/10 21:12:10  bjornw
 *  loops_per_sec -> loops_per_jiffy
 *
 *  Revision 1.14  2000/11/22 16:23:20  bjornw
 *  Initialize totalhigh counters to 0 to make /proc/meminfo look nice.
 *
 *  Revision 1.13  2000/11/21 16:37:51  bjornw
 *  Temporarily disable initmem freeing
 *
 *  Revision 1.12  2000/11/21 13:55:07  bjornw
 *  Use CONFIG_CRIS_LOW_MAP for the low VM map instead of explicit CPU type
 *
 *  Revision 1.11  2000/10/06 12:38:22  bjornw
 *  Cast empty_bad_page correctly (should really be of * type from the start..
 *
 *  Revision 1.10  2000/10/04 16:53:57  bjornw
 *  Fix memory-map due to LX features
 *
 *  Revision 1.9  2000/09/13 15:47:49  bjornw
 *  Wrong count in reserved-pages loop
 *
 *  Revision 1.8  2000/09/13 14:35:10  bjornw
 *  2.4.0-test8 added a new arg to free_area_init_node
 *
 *  Revision 1.7  2000/08/17 15:35:55  bjornw
 *  2.4.0-test6 removed MAP_NR and inserted virt_to_page
 *
 *
 */

#include <linux/config.h>
#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/mm.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/bootmem.h>

#include <asm/system.h>
#include <asm/segment.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/dma.h>
#include <asm/svinto.h>
#include <asm/io.h>
#include <asm/mmu_context.h>

static unsigned long totalram_pages;

struct pgtable_cache_struct quicklists;  /* see asm/pgalloc.h */

const char bad_pmd_string[] = "Bad pmd in pte_alloc: %08lx\n";

extern void die_if_kernel(char *,struct pt_regs *,long);
extern void show_net_buffers(void);
extern void tlb_init(void);


unsigned long empty_zero_page;

/* trim the page-table cache if necessary */

int 
do_check_pgt_cache(int low, int high)
{
        int freed = 0;

        if(pgtable_cache_size > high) {
                do {
                        if(pgd_quicklist) {
                                free_pgd_slow(get_pgd_fast());
                                freed++;
                        }
                        if(pmd_quicklist) {
                                pmd_free_slow(pmd_alloc_one_fast(NULL, 0));
                                freed++;
                        }
                        if(pte_quicklist) {
                                pte_free_slow(pte_alloc_one_fast(NULL, 0));
				freed++;
                        }
                } while(pgtable_cache_size > low);
        }
        return freed;
}

void 
show_mem(void)
{
	int i,free = 0,total = 0,cached = 0, reserved = 0, nonshared = 0;
	int shared = 0;

	printk("\nMem-info:\n");
	show_free_areas();
	printk("Free swap:       %6dkB\n",nr_swap_pages<<(PAGE_SHIFT-10));
	i = max_mapnr;
	while (i-- > 0) {
		total++;
		if (PageReserved(mem_map+i))
			reserved++;
		else if (PageSwapCache(mem_map+i))
			cached++;
		else if (!page_count(mem_map+i))
			free++;
		else if (page_count(mem_map+i) == 1)
			nonshared++;
		else
			shared += page_count(mem_map+i) - 1;
	}
	printk("%d pages of RAM\n",total);
	printk("%d free pages\n",free);
	printk("%d reserved pages\n",reserved);
	printk("%d pages nonshared\n",nonshared);
	printk("%d pages shared\n",shared);
	printk("%d pages swap cached\n",cached);
	printk("%ld pages in page table cache\n",pgtable_cache_size);
	show_buffers();
}

/*
 * The kernel is already mapped with a kernel segment at kseg_c so 
 * we don't need to map it with a page table. However head.S also
 * temporarily mapped it at kseg_4 so we should set up the ksegs again,
 * clear the TLB and do some other paging setup stuff.
 */

void __init 
paging_init(void)
{
	int i;
	unsigned long zones_size[MAX_NR_ZONES];

	printk("Setting up paging and the MMU.\n");
	
	/* clear out the init_mm.pgd that will contain the kernel's mappings */

	for(i = 0; i < PTRS_PER_PGD; i++)
		swapper_pg_dir[i] = __pgd(0);
	
	/* make sure the current pgd table points to something sane
	 * (even if it is most probably not used until the next 
	 *  switch_mm)
	 */

	current_pgd = init_mm.pgd;

	/* initialise the TLB (tlb.c) */

	tlb_init();

	/* see README.mm for details on the KSEG setup */

#ifndef CONFIG_CRIS_LOW_MAP
	/* This code is for the corrected Etrax-100 LX version 2... */

	*R_MMU_KSEG = ( IO_STATE(R_MMU_KSEG, seg_f, seg  ) | /* cached flash */
			IO_STATE(R_MMU_KSEG, seg_e, seg  ) | /* uncached flash */
			IO_STATE(R_MMU_KSEG, seg_d, page ) | /* vmalloc area */
			IO_STATE(R_MMU_KSEG, seg_c, seg  ) | /* kernel area */
			IO_STATE(R_MMU_KSEG, seg_b, seg  ) | /* kernel reg area */
			IO_STATE(R_MMU_KSEG, seg_a, page ) | /* user area */
			IO_STATE(R_MMU_KSEG, seg_9, page ) |
			IO_STATE(R_MMU_KSEG, seg_8, page ) |
			IO_STATE(R_MMU_KSEG, seg_7, page ) |
			IO_STATE(R_MMU_KSEG, seg_6, page ) |
			IO_STATE(R_MMU_KSEG, seg_5, page ) |
			IO_STATE(R_MMU_KSEG, seg_4, page ) |
			IO_STATE(R_MMU_KSEG, seg_3, page ) |
			IO_STATE(R_MMU_KSEG, seg_2, page ) |
			IO_STATE(R_MMU_KSEG, seg_1, page ) |
			IO_STATE(R_MMU_KSEG, seg_0, page ) );

	*R_MMU_KBASE_HI = ( IO_FIELD(R_MMU_KBASE_HI, base_f, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_HI, base_e, 0x8 ) |
			    IO_FIELD(R_MMU_KBASE_HI, base_d, 0x0 ) |
			    IO_FIELD(R_MMU_KBASE_HI, base_c, 0x4 ) |