path: root/arch/x86/kernel/e820_64.c

/*
 * Handle the memory map.
 * The functions here do the job until bootmem takes over.
 *
 *  Getting sanitize_e820_map() in sync with i386 version by applying change:
 *  -  Provisions for empty E820 memory regions (reported by certain BIOSes).
 *     Alex Achenbach <xela@slit.de>, December 2002.
 *  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
 *
 */
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/ioport.h>
#include <linux/string.h>
#include <linux/kexec.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/suspend.h>
#include <linux/pfn.h>

#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/e820.h>
#include <asm/proto.h>
#include <asm/setup.h>
#include <asm/sections.h>
#include <asm/kdebug.h>

struct e820map e820;

/*
 * PFN of last memory page.
 */
unsigned long end_pfn;

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

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

/*
 * Early reserved memory areas.
 */
#define MAX_EARLY_RES 20

struct early_res {
	unsigned long start, end;
	char name[16];
};
static struct early_res early_res[MAX_EARLY_RES] __initdata = {
	{ 0, PAGE_SIZE, "BIOS data page" },			/* BIOS data page */
#ifdef CONFIG_SMP
	{ SMP_TRAMPOLINE_BASE, SMP_TRAMPOLINE_BASE + 2*PAGE_SIZE, "SMP_TRAMPOLINE" },
#endif
	{}
};

void __init reserve_early(unsigned long start, unsigned long end, char *name)
{
	int i;
	struct early_res *r;
	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
		r = &early_res[i];
		if (end > r->start && start < r->end)
			panic("Overlapping early reservations %lx-%lx %s to %lx-%lx %s\n",
			      start, end - 1, name?name:"", r->start, r->end - 1, r->name);
	}
	if (i >= MAX_EARLY_RES)
		panic("Too many early reservations");
	r = &early_res[i];
	r->start = start;
	r->end = end;
	if (name)
		strncpy(r->name, name, sizeof(r->name) - 1);
}

void __init early_res_to_bootmem(void)
{
	int i;
	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
		struct early_res *r = &early_res[i];
		printk(KERN_INFO "early res: %d [%lx-%lx] %s\n", i,
			r->start, r->end - 1, r->name);
		reserve_bootmem_generic(r->start, r->end - r->start);
	}
}

/* Check for already reserved areas */
static inline int
bad_addr(unsigned long *addrp, unsigned long size, unsigned long align)
{
	int i;
	unsigned long addr = *addrp, last;
	int changed = 0;
again:
	last = addr + size;
	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
		struct early_res *r = &early_res[i];
		if (last >= r->start && addr < r->end) {
			*addrp = addr = round_up(r->end, align);
			changed = 1;
			goto again;
		}
	}
	return changed;
}

/* Check for already reserved areas */
static inline int
bad_addr_size(unsigned long *addrp, unsigned long *sizep, unsigned long align)
{
	int i;
	unsigned long addr = *addrp, last;
	unsigned long size = *sizep;
	int changed = 0;
again:
	last = addr + size;
	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
		struct early_res *r = &early_res[i];
		if (last > r->start && addr < r->start) {
			size = r->start - addr;
			changed = 1;
			goto again;
		}
		if (last > r->end && addr < r->end) {
			addr = round_up(r->end, align);
			size = last - addr;
			changed = 1;
			goto again;
		}