init.c

这个linux源代码是很全面的~基本完整了~使用c编译的~由于时间问题我没有亲自测试~但就算用来做参考资料也是非常好的

/*
 *  linux/arch/parisc/mm/init.c
 *
 *  Copyright (C) 1995	Linus Torvalds
 *  Copyright 1999 SuSE GmbH
 *    changed by Philipp Rumpf
 *  Copyright 1999 Philipp Rumpf ([e-mail])
 *
 */

#include <linux/config.h>

#include <linux/mm.h>
#include <linux/bootmem.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/pci.h>		/* for hppa_dma_ops and pcxl_dma_ops */
#include <linux/blk.h>          /* for initrd_start and initrd_end */
#include <linux/swap.h>
#include <linux/unistd.h>

#include <asm/pgalloc.h>
#include <asm/tlb.h>

mmu_gather_t mmu_gathers[NR_CPUS];

extern char _text;	/* start of kernel code, defined by linker */
extern int  data_start;
extern char _end;	/* end of BSS, defined by linker */
extern char __init_begin, __init_end;

#ifdef CONFIG_DISCONTIGMEM
struct node_map_data node_data[MAX_PHYSMEM_RANGES];
bootmem_data_t bmem_data[MAX_PHYSMEM_RANGES];
unsigned char *chunkmap;
unsigned int maxchunkmap;
#endif

static struct resource data_resource = {
	name:	"Kernel data",
	flags:	IORESOURCE_BUSY | IORESOURCE_MEM,
};

static struct resource code_resource = {
	name:	"Kernel code",
	flags:	IORESOURCE_BUSY | IORESOURCE_MEM,
};

static struct resource pdcdata_resource = {
	name:	"PDC data (Page Zero)",
	start:	0,
	end:	0x9ff,
	flags:	IORESOURCE_BUSY | IORESOURCE_MEM,
};

static struct resource sysram_resources[MAX_PHYSMEM_RANGES];

static unsigned long max_pfn;

/* The following array is initialized from the firmware specific
 * information retrieved in kernel/inventory.c.
 */

physmem_range_t pmem_ranges[MAX_PHYSMEM_RANGES];
int npmem_ranges;

#ifdef __LP64__
#define MAX_MEM         (~0UL)
#else /* !__LP64__ */
#define MAX_MEM         (3584U*1024U*1024U)
#endif /* !__LP64__ */

static unsigned long mem_limit = MAX_MEM;

static void __init mem_limit_func(void)
{
	char *cp, *end;
	unsigned long limit;
	extern char saved_command_line[];

	/* We need this before __setup() functions are called */

	limit = MAX_MEM;
	for (cp = saved_command_line; *cp; ) {
		if (memcmp(cp, "mem=", 4) == 0) {
			cp += 4;
			limit = memparse(cp, &end);
			if (end != cp)
				break;
			cp = end;
		} else {
			while (*cp != ' ' && *cp)
				++cp;
			while (*cp == ' ')
				++cp;
		}
	}

	if (limit < mem_limit)
		mem_limit = limit;
}

#define MAX_GAP (0x40000000UL >> PAGE_SHIFT)

static void __init setup_bootmem(void)
{
	unsigned long bootmap_size;
	unsigned long mem_max;
	unsigned long bootmap_pages;
	unsigned long bootmap_start_pfn;
	unsigned long bootmap_pfn;
#ifndef CONFIG_DISCONTIGMEM
	physmem_range_t pmem_holes[MAX_PHYSMEM_RANGES - 1];
	int npmem_holes;
#endif
	int i, sysram_resource_count;

	disable_sr_hashing(); /* Turn off space register hashing */

#ifdef CONFIG_DISCONTIGMEM
	/*
	 * The below is still true as of 2.4.2. If this is ever fixed,
	 * we can remove this warning!
	 */

	printk(KERN_WARNING "\n\n");
	printk(KERN_WARNING "CONFIG_DISCONTIGMEM is enabled, which is probably a mistake. This\n");
	printk(KERN_WARNING "option can lead to heavy swapping, even when there are gigabytes\n");
	printk(KERN_WARNING "of free memory.\n\n");
#endif

#ifdef __LP64__

#ifndef CONFIG_DISCONTIGMEM
	/*
	 * Sort the ranges. Since the number of ranges is typically
	 * small, and performance is not an issue here, just do
	 * a simple insertion sort.
	 */

	for (i = 1; i < npmem_ranges; i++) {
		int j;

		for (j = i; j > 0; j--) {
			unsigned long tmp;

			if (pmem_ranges[j-1].start_pfn <
			    pmem_ranges[j].start_pfn) {

				break;
			}
			tmp = pmem_ranges[j-1].start_pfn;
			pmem_ranges[j-1].start_pfn = pmem_ranges[j].start_pfn;
			pmem_ranges[j].start_pfn = tmp;
			tmp = pmem_ranges[j-1].pages;
			pmem_ranges[j-1].pages = pmem_ranges[j].pages;
			pmem_ranges[j].pages = tmp;
		}
	}

	/*
	 * Throw out ranges that are too far apart (controlled by
	 * MAX_GAP). If CONFIG_DISCONTIGMEM wasn't implemented so
	 * poorly, we would recommend enabling that option, but,
	 * until it is fixed, this is the best way to go.
	 */

	for (i = 1; i < npmem_ranges; i++) {
		if (pmem_ranges[i].start_pfn -
			(pmem_ranges[i-1].start_pfn +
			 pmem_ranges[i-1].pages) > MAX_GAP) {
			npmem_ranges = i;
			break;
		}
	}
#endif

	if (npmem_ranges > 1) {

		/* Print the memory ranges */

		printk(KERN_INFO "Memory Ranges:\n");

		for (i = 0; i < npmem_ranges; i++) {
			unsigned long start;
			unsigned long size;

			size = (pmem_ranges[i].pages << PAGE_SHIFT);
			start = (pmem_ranges[i].start_pfn << PAGE_SHIFT);
			printk(KERN_INFO "%2d) Start 0x%016lx End 0x%016lx Size %6ld Mb\n",
				i,start, start + (size - 1), size >> 20);
		}
	}

#endif /* __LP64__ */

#if 1
	/* KLUGE! this really belongs in kernel/resource.c! */
	iomem_resource.end = ~0UL;
#endif

	sysram_resource_count = npmem_ranges;
	for (i = 0; i < sysram_resource_count; i++) {
		struct resource *res = &sysram_resources[i];
		res->name = "System RAM";
		res->start = pmem_ranges[i].start_pfn << PAGE_SHIFT;
		res->end = res->start + (pmem_ranges[i].pages << PAGE_SHIFT)-1;
		res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
		request_resource(&iomem_resource, res);
	}

	/*
	 * For 32 bit kernels we limit the amount of memory we can
	 * support, in order to preserve enough kernel address space
	 * for other purposes. For 64 bit kernels we don't normally
	 * limit the memory, but this mechanism can be used to
	 * artificially limit the amount of memory (and it is written
	 * to work with multiple memory ranges).
	 */

	mem_limit_func();       /* check for "mem=" argument */

	mem_max = 0;
	for (i = 0; i < npmem_ranges; i++) {
		unsigned long rsize;

		rsize = pmem_ranges[i].pages << PAGE_SHIFT;
		if ((mem_max + rsize) > mem_limit) {
			printk(KERN_WARNING "Memory truncated to %ld Mb\n", mem_limit >> 20);
			if (mem_max == mem_limit)
				npmem_ranges = i;
			else {
				pmem_ranges[i].pages =   (mem_limit >> PAGE_SHIFT)
						       - (mem_max >> PAGE_SHIFT);
				npmem_ranges = i + 1;
				mem_max = mem_limit;
			}
			break;
		}
		mem_max += rsize;
	}

	printk(KERN_INFO "Total Memory: %ld Mb\n",mem_max >> 20);

#ifndef CONFIG_DISCONTIGMEM

	/* Merge the ranges, keeping track of the holes */

	{
		unsigned long end_pfn;
		unsigned long hole_pages;

		npmem_holes = 0;
		end_pfn = pmem_ranges[0].start_pfn + pmem_ranges[0].pages;
		for (i = 1; i < npmem_ranges; i++) {

			hole_pages = pmem_ranges[i].start_pfn - end_pfn;
			if (hole_pages) {
				pmem_holes[npmem_holes].start_pfn = end_pfn;
				pmem_holes[npmem_holes++].pages = hole_pages;
				end_pfn += hole_pages;
			}
			end_pfn += pmem_ranges[i].pages;
		}

		pmem_ranges[0].pages = end_pfn - pmem_ranges[0].start_pfn;
		npmem_ranges = 1;
	}
#endif

	bootmap_pages = 0;
	for (i = 0; i < npmem_ranges; i++)
		bootmap_pages += bootmem_bootmap_pages(pmem_ranges[i].pages);

	bootmap_start_pfn = PAGE_ALIGN(__pa((unsigned long) &_end)) >> PAGE_SHIFT;

#ifdef CONFIG_DISCONTIGMEM
	for (i = 0; i < npmem_ranges; i++)
		node_data[i].pg_data.bdata = &bmem_data[i];
#endif
	/*
	 * Initialize and free the full range of memory in each range.
	 * Note that the only writing these routines do are to the bootmap,
	 * and we've made sure to locate the bootmap properly so that they
	 * won't be writing over anything important.
	 */

	bootmap_pfn = bootmap_start_pfn;
	max_pfn = 0;
	for (i = 0; i < npmem_ranges; i++) {
		unsigned long start_pfn;
		unsigned long npages;

		start_pfn = pmem_ranges[i].start_pfn;
		npages = pmem_ranges[i].pages;

		bootmap_size = init_bootmem_node(NODE_DATA(i),
						bootmap_pfn,
						start_pfn,
						(start_pfn + npages) );
		free_bootmem_node(NODE_DATA(i),
				  (start_pfn << PAGE_SHIFT),
				  (npages << PAGE_SHIFT) );
		bootmap_pfn += (bootmap_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
		if ((start_pfn + npages) > max_pfn)
			max_pfn = start_pfn + npages;
	}

	if ((bootmap_pfn - bootmap_start_pfn) != bootmap_pages) {
		printk(KERN_WARNING "WARNING! bootmap sizing is messed up!\n");
		BUG();
	}

	/* reserve PAGE0 pdc memory, kernel text/data/bss & bootmap */

#define PDC_CONSOLE_IO_IODC_SIZE 32768

	reserve_bootmem_node(NODE_DATA(0), 0UL,
			(unsigned long)(PAGE0->mem_free + PDC_CONSOLE_IO_IODC_SIZE));
	reserve_bootmem_node(NODE_DATA(0),__pa((unsigned long)&_text),
			(unsigned long)(&_end - &_text));
	reserve_bootmem_node(NODE_DATA(0), (bootmap_start_pfn << PAGE_SHIFT),
			((bootmap_pfn - bootmap_start_pfn) << PAGE_SHIFT));

#ifndef CONFIG_DISCONTIGMEM

	/* reserve the holes */

	for (i = 0; i < npmem_holes; i++) {
		reserve_bootmem_node(NODE_DATA(0),
				(pmem_holes[i].start_pfn << PAGE_SHIFT),
				(pmem_holes[i].pages << PAGE_SHIFT));
	}
#endif

#ifdef CONFIG_BLK_DEV_INITRD
	if (initrd_start) {
		printk(KERN_INFO "initrd: %08lx-%08lx\n", initrd_start, initrd_end);
		if (__pa(initrd_start) < mem_max) {
			unsigned long initrd_reserve;

			if (__pa(initrd_end) > mem_max) {
				initrd_reserve = mem_max - __pa(initrd_start);
			} else {
				initrd_reserve = initrd_end - initrd_start;
			}
			initrd_below_start_ok = 1;
			printk(KERN_INFO "initrd: reserving %08lx-%08lx (mem_max %08lx)\n", __pa(initrd_start), __pa(initrd_start) + initrd_reserve, mem_max);

			reserve_bootmem_node(NODE_DATA(0),__pa(initrd_start), initrd_reserve);
		}
	}
#endif

	data_resource.start =  virt_to_phys(&data_start);
	data_resource.end = virt_to_phys(&_end)-1;
	code_resource.start = virt_to_phys(&_text);
	code_resource.end = virt_to_phys(&data_start)-1;

	/* We don't know which region the kernel will be in, so try
	 * all of them.
	 */
	for (i = 0; i < sysram_resource_count; i++) {
		struct resource *res = &sysram_resources[i];
		request_resource(res, &code_resource);
		request_resource(res, &data_resource);
	}
	request_resource(&sysram_resources[0], &pdcdata_resource);
}

void free_initmem(void)
{
	/* FIXME: */
#if 0
	printk(KERN_INFO "NOT FREEING INITMEM (%dk)\n",
			(&__init_end - &__init_begin) >> 10);
	return;
#endif
	unsigned long addr;
	
	printk(KERN_INFO "Freeing unused kernel memory: ");

#if 1
	/* Attempt to catch anyone trying to execute code here
	 * by filling the page with BRK insns.
	 * 
	 * If we disable interrupts for all CPUs, then IPI stops working.
	 * Kinda breaks the global cache flushing.
	 */
	local_irq_disable();

	memset(&__init_begin, 0x00, 
		(unsigned long)&__init_end - (unsigned long)&__init_begin);

	flush_data_cache();
	asm volatile("sync" : : );
	flush_icache_range((unsigned long)&__init_begin, (unsigned long)&__init_end);
	asm volatile("sync" : : );

	local_irq_enable();
#endif
	
	addr = (unsigned long)(&__init_begin);
	for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
		ClearPageReserved(virt_to_page(addr));
		set_page_count(virt_to_page(addr), 1);
		free_page(addr);
		num_physpages++;
	}

	printk("%luk freed\n", (unsigned long)(&__init_end - &__init_begin) >> 10);
}

/*
 * Just an arbitrary offset to serve as a "hole" between mapping areas
 * (between top of physical memory and a potential pcxl dma mapping
 * area, and below the vmalloc mapping area).
 *
 * The current 32K value just means that there will be a 32K "hole"
 * between mapping areas. That means that  any out-of-bounds memory
 * accesses will hopefully be caught. The vmalloc() routines leaves
 * a hole of 4kB between each vmalloced area for the same reason.
 */

#define MAP_START 0x4000 /* Leave room for gateway page expansion */
#define VM_MAP_OFFSET  (32*1024)
#define SET_MAP_OFFSET(x) ((void *)(((unsigned long)(x) + VM_MAP_OFFSET) \
				     & ~(VM_MAP_OFFSET-1)))

void *vmalloc_start;
#ifdef CONFIG_PA11
unsigned long pcxl_dma_start;
#endif

void __init mem_init(void)
{
	int i;

	high_memory = __va((max_pfn << PAGE_SHIFT));
	max_mapnr = (virt_to_page(high_memory - 1) - mem_map) + 1;

	num_physpages = 0;
	for (i = 0; i < npmem_ranges; i++)
		num_physpages += free_all_bootmem_node(NODE_DATA(i));

	printk(KERN_INFO "Memory: %luk available\n", num_physpages << (PAGE_SHIFT-10));

#ifdef CONFIG_PA11
	if (hppa_dma_ops == &pcxl_dma_ops) {
	    pcxl_dma_start = (unsigned long)SET_MAP_OFFSET(MAP_START);
	    vmalloc_start = SET_MAP_OFFSET(pcxl_dma_start + PCXL_DMA_MAP_SIZE);
	}
	else {
	    pcxl_dma_start = 0;
	    vmalloc_start = SET_MAP_OFFSET(MAP_START);
	}
#else
	vmalloc_start = SET_MAP_OFFSET(MAP_START);
#endif

}

int do_check_pgt_cache(int low, int high)
{
	return 0;
}

unsigned long *empty_zero_page;

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

	printk(KERN_INFO "Mem-info:\n");
	show_free_areas();
	printk(KERN_INFO "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 (!atomic_read(&mem_map[i].count))
			free++;
		else
			shared += atomic_read(&mem_map[i].count) - 1;
	}
	printk(KERN_INFO "%d pages of RAM\n", total);
	printk(KERN_INFO "%d reserved pages\n", reserved);
	printk(KERN_INFO "%d pages shared\n", shared);
	printk(KERN_INFO "%d pages swap cached\n", cached);
	show_buffers();
}


static void __init map_pages(unsigned long start_vaddr, unsigned long start_paddr, unsigned long size, pgprot_t pgprot)
{
	pgd_t *pg_dir;
	pmd_t *pmd;
	pte_t *pg_table;
	unsigned long end_paddr;
	unsigned long start_pmd;
	unsigned long start_pte;
	unsigned long tmp1;
	unsigned long tmp2;
	unsigned long address;
	unsigned long ro_start;
	unsigned long ro_end;
	unsigned long fv_addr;