e820.c

来自「linux-2.4.29操作系统的源码」· C语言 代码 · 共 609 行 · 第 1/2 页

/* 
 * Handle the memory map.
 * The functions here do the job until bootmem takes over.
 * $Id: e820.c,v 1.13 2004/03/22 00:31:08 ak Exp $
 */
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/acpi.h>
#include <linux/bootmem.h>
#include <linux/ioport.h>
#include <asm/page.h>
#include <asm/e820.h>
#include <asm/proto.h>
#include <asm/acpi.h>
#include <asm/apic.h>
#include <asm/bootsetup.h>
#include <asm/mpspec.h>
#include <asm/io_apic.h>

extern unsigned long table_start, table_end;
extern char _end[];

#ifdef	CONFIG_ACPI_BOOT
extern acpi_interrupt_flags	acpi_sci_flags;
#endif

extern struct resource code_resource, data_resource, vram_resource;

/* Check for some hardcoded bad areas that early boot is not allowed to touch */ 
static inline int bad_addr(unsigned long *addrp, unsigned long size)
{ 
	unsigned long addr = *addrp, last = addr + size; 

	/* various gunk below that needed for SMP startup */
	if (addr < 7*PAGE_SIZE) { 
		*addrp = 7*PAGE_SIZE; 
		return 1; 
	}
	/* direct mapping tables of the kernel */
	if (last >= table_start<<PAGE_SHIFT && addr < table_end<<PAGE_SHIFT) { 
		*addrp = table_end << PAGE_SHIFT; 
		return 1;
	} 
	/* initrd */ 
#ifdef CONFIG_BLK_DEV_INITRD
	if (LOADER_TYPE && INITRD_START && last >= INITRD_START && 
	    addr < INITRD_START+INITRD_SIZE) { 
		*addrp = INITRD_START + INITRD_SIZE; 
		return 1;
	} 
#endif
	/* kernel code + 640k memory hole (later should not be needed, but 
	   be paranoid for now) */
	if (last >= 640*1024 && addr < __pa_symbol(&_end)) { 
		*addrp = __pa_symbol(&_end);
		return 1;
	}
	/* XXX ramdisk image here? */ 
	return 0;
} 

int __init e820_mapped(unsigned long start, unsigned long end, int type) 
{ 
	int i;
	for (i = 0; i < e820.nr_map; i++) { 
		struct e820entry *ei = &e820.map[i]; 
		if (type && ei->type != type) 
			continue;
		if (ei->addr >= end || ei->addr + ei->size < start) 
			continue; 
		return 1; 
	} 
	return 0;
}

/* 
 * Find a free area in a specific range. 
 */ 
unsigned long __init find_e820_area(unsigned long start, unsigned long end, unsigned size) 
{ 
	int i; 
	for (i = 0; i < e820.nr_map; i++) { 
		struct e820entry *ei = &e820.map[i]; 
		unsigned long addr = ei->addr, last; 
		if (ei->type != E820_RAM) 
			continue; 
		if (addr < start) 
			addr = start;
		if (addr > ei->addr + ei->size) 
			continue; 
		while (bad_addr(&addr, size) && addr+size < ei->addr + ei->size)
			;
		last = addr + size;
		if (last > ei->addr + ei->size)
			continue;
		if (last > end) 
			continue;
		return addr; 
	} 
	return -1UL;		
} 

/* 
 * Free bootmem based on the e820 table for a node.
 */
void __init e820_bootmem_free(pg_data_t *pgdat, unsigned long start,unsigned long end)
{
	int i;
	for (i = 0; i < e820.nr_map; i++) {
		struct e820entry *ei = &e820.map[i]; 
		unsigned long last, addr;

		if (ei->type != E820_RAM || 
		    ei->addr+ei->size <= start || 
		    ei->addr > end)
			continue;

		addr = round_up(ei->addr, PAGE_SIZE);
		if (addr < start) 
			addr = start;

		last = round_down(ei->addr + ei->size, PAGE_SIZE); 
		if (last >= end)
			last = end; 

		if (last > addr && last-addr >= PAGE_SIZE)
			free_bootmem_node(pgdat, addr, last-addr);
	}
}

/*
 * end_pfn only includes RAM, while end_pfn_map includes all e820 entries.
 * The direct mapping extends to end_pfn_map, so that we can directly access
 * ACPI and other tables without having to play with fixmaps.
 */ 
unsigned long end_pfn_map; 

/* 
 * Last pfn which the user wants to use.
 */
unsigned long end_user_pfn = MAXMEM>>PAGE_SHIFT;  

/*
 * Find the highest page frame number we have available
 */

void __init e820_end_of_ram(void)
{
	int i;
	end_pfn = 0;
	
	for (i = 0; i < e820.nr_map; i++) {
		struct e820entry *ei = &e820.map[i]; 
		unsigned long start, end;

		start = round_up(ei->addr, PAGE_SIZE); 
		end = round_down(ei->addr + ei->size, PAGE_SIZE); 
		if (start >= end)
			continue;
		if (ei->type == E820_RAM) { 
		if (end > end_pfn<<PAGE_SHIFT)
			end_pfn = end>>PAGE_SHIFT;
		} else { 
			if (end > end_pfn_map<<PAGE_SHIFT) 
				end_pfn_map = end>>PAGE_SHIFT;
		} 
	}

	if (end_pfn > end_pfn_map) 
		end_pfn_map = end_pfn;
	if (end_pfn_map > MAXMEM>>PAGE_SHIFT)
		end_pfn_map = MAXMEM>>PAGE_SHIFT;
	if (end_pfn > end_user_pfn)
		end_pfn = end_user_pfn;
	if (end_pfn > end_pfn_map) 
		end_pfn = end_pfn_map; 
}

/* 
 * Mark e820 reserved areas as busy for the resource manager.
 */
void __init e820_reserve_resources(void)
{
	int i;
	for (i = 0; i < e820.nr_map; i++) {
		struct resource *res;
		if (e820.map[i].addr + e820.map[i].size > 0x100000000ULL)
			continue;
		res = alloc_bootmem_low(sizeof(struct resource));
		switch (e820.map[i].type) {
		case E820_RAM:	res->name = "System RAM"; break;
		case E820_ACPI:	res->name = "ACPI Tables"; break;
		case E820_NVS:	res->name = "ACPI Non-volatile Storage"; break;
		default:	res->name = "reserved";
		}
		res->start = e820.map[i].addr;
		res->end = res->start + e820.map[i].size - 1;
		res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
		request_resource(&iomem_resource, res);
		if (e820.map[i].type == E820_RAM) {
			/*
			 *  We dont't know which RAM region contains kernel data,
			 *  so we try it repeatedly and let the resource manager
			 *  test it.
			 */
			request_resource(res, &code_resource);
			request_resource(res, &data_resource);
		}
	}
}

/* 
 * Add a memory region to the kernel e820 map.
 */ 
void __init add_memory_region(unsigned long start, unsigned long size, int type)
{
	int x = e820.nr_map;

	if (x == E820MAX) {
		printk(KERN_ERR "Ooops! Too many entries in the memory map!\n");
		return;
	}

	e820.map[x].addr = start;
	e820.map[x].size = size;
	e820.map[x].type = type;
	e820.nr_map++;
}

void __init e820_print_map(char *who)
{
	int i;

	for (i = 0; i < e820.nr_map; i++) {
		printk(" %s: %016Lx - %016Lx ", who,
			(unsigned long long) e820.map[i].addr,
			(unsigned long long) (e820.map[i].addr + e820.map[i].size));
		switch (e820.map[i].type) {
		case E820_RAM:	printk("(usable)\n");
				break;
		case E820_RESERVED:
				printk("(reserved)\n");
				break;
		case E820_ACPI:
				printk("(ACPI data)\n");
				break;
		case E820_NVS:
				printk("(ACPI NVS)\n");
				break;
		default:	printk("type %u\n", e820.map[i].type);
				break;
		}
	}
}

/*
 * Sanitize the BIOS e820 map.
 *
 * Some e820 responses include overlapping entries.  The following 
 * replaces the original e820 map with a new one, removing overlaps.
 *
 */
static int __init sanitize_e820_map(struct e820entry * biosmap, char * pnr_map)
{
	struct change_member {
		struct e820entry *pbios; /* pointer to original bios entry */
		unsigned long long addr; /* address for this change point */
	};
	static struct change_member change_point_list[2*E820MAX] __initdata;
	static struct change_member *change_point[2*E820MAX] __initdata;
	static struct e820entry *overlap_list[E820MAX] __initdata;
	static struct e820entry new_bios[E820MAX] __initdata;
	struct change_member *change_tmp;
	unsigned long current_type, last_type;
	unsigned long long last_addr;
	int chgidx, still_changing;
	int overlap_entries;
	int new_bios_entry;
	int old_nr, new_nr;
	int i;

	/*
		Visually we're performing the following (1,2,3,4 = memory types)...

		Sample memory map (w/overlaps):
		   ____22__________________
		   ______________________4_
		   ____1111________________
		   _44_____________________
		   11111111________________
		   ____________________33__
		   ___________44___________
		   __________33333_________
		   ______________22________
		   ___________________2222_
		   _________111111111______
		   _____________________11_
		   _________________4______

		Sanitized equivalent (no overlap):
		   1_______________________
		   _44_____________________
		   ___1____________________