mm_contig.c

xen虚拟机源代码安装包

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1998-2003 Hewlett-Packard Co
 *	David Mosberger-Tang <[e-mail]>
 *	Stephane Eranian <[e-mail]>
 * Copyright (C) 2000, Rohit Seth <[e-mail]>
 * Copyright (C) 1999 VA Linux Systems
 * Copyright (C) 1999 Walt Drummond <[e-mail]>
 * Copyright (C) 2003 Silicon Graphics, Inc. All rights reserved.
 *
 * Routines used by ia64 machines with contiguous (or virtually contiguous)
 * memory.
 */
#include <linux/config.h>
#include <linux/bootmem.h>
#include <linux/mm.h>
#include <linux/swap.h>

#include <asm/meminit.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/sections.h>
#include <asm/mca.h>

#include <linux/efi.h>
#ifdef CONFIG_VIRTUAL_MEM_MAP
static unsigned long num_dma_physpages;
#endif

/**
 * show_mem - display a memory statistics summary
 *
 * Just walks the pages in the system and describes where they're allocated.
 */
#ifndef XEN
void
show_mem (void)
{
	int i, total = 0, reserved = 0;
	int shared = 0, cached = 0;

	printk("Mem-info:\n");
	show_free_areas();

	printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
	i = max_mapnr;
	while (i-- > 0) {
		if (!mfn_valid(i))
			continue;
		total++;
		if (PageReserved(mem_map+i))
			reserved++;
		else if (PageSwapCache(mem_map+i))
			cached++;
		else if (page_count(mem_map + i))
			shared += page_count(mem_map + i) - 1;
	}
	printk("%d pages of RAM\n", total);
	printk("%d reserved pages\n", reserved);
	printk("%d pages shared\n", shared);
	printk("%d pages swap cached\n", cached);
	printk("%ld pages in page table cache\n",
		pgtable_quicklist_total_size());
}
#endif

/* physical address where the bootmem map is located */
unsigned long bootmap_start;

/**
 * find_max_pfn - adjust the maximum page number callback
 * @start: start of range
 * @end: end of range
 * @arg: address of pointer to global max_pfn variable
 *
 * Passed as a callback function to efi_memmap_walk() to determine the highest
 * available page frame number in the system.
 */
int
find_max_pfn (unsigned long start, unsigned long end, void *arg)
{
	unsigned long *max_pfnp = arg, pfn;

	pfn = (PAGE_ALIGN(end - 1) - PAGE_OFFSET) >> PAGE_SHIFT;
	if (pfn > *max_pfnp)
		*max_pfnp = pfn;
	return 0;
}

/**
 * find_bootmap_location - callback to find a memory area for the bootmap
 * @start: start of region
 * @end: end of region
 * @arg: unused callback data
 *
 * Find a place to put the bootmap and return its starting address in
 * bootmap_start.  This address must be page-aligned.
 */
int
find_bootmap_location (unsigned long start, unsigned long end, void *arg)
{
	unsigned long needed = *(unsigned long *)arg;
	unsigned long range_start, range_end, free_start;
	int i;

#if IGNORE_PFN0
	if (start == PAGE_OFFSET) {
		start += PAGE_SIZE;
		if (start >= end)
			return 0;
	}
#endif

	free_start = PAGE_OFFSET;

	for (i = 0; i < num_rsvd_regions; i++) {
		range_start = max(start, free_start);
		range_end   = min(end, rsvd_region[i].start & PAGE_MASK);

		free_start = PAGE_ALIGN(rsvd_region[i].end);

		if (range_end <= range_start)
			continue; /* skip over empty range */

		if (range_end - range_start >= needed) {
			bootmap_start = __pa(range_start);
			return -1;	/* done */
		}

		/* nothing more available in this segment */
		if (range_end == end)
			return 0;
	}
	return 0;
}

/**
 * find_memory - setup memory map
 *
 * Walk the EFI memory map and find usable memory for the system, taking
 * into account reserved areas.
 */
#ifndef XEN
void
find_memory (void)
{
	unsigned long bootmap_size;

	reserve_memory();

	/* first find highest page frame number */
	max_pfn = 0;
	efi_memmap_walk(find_max_pfn, &max_pfn);

	/* how many bytes to cover all the pages */
	bootmap_size = bootmem_bootmap_pages(max_pfn) << PAGE_SHIFT;

	/* look for a location to hold the bootmap */
	bootmap_start = ~0UL;
	efi_memmap_walk(find_bootmap_location, &bootmap_size);
	if (bootmap_start == ~0UL)
		panic("Cannot find %ld bytes for bootmap\n", bootmap_size);

	bootmap_size = init_bootmem(bootmap_start >> PAGE_SHIFT, max_pfn);

	/* Free all available memory, then mark bootmem-map as being in use. */
	efi_memmap_walk(filter_rsvd_memory, free_bootmem);
	reserve_bootmem(bootmap_start, bootmap_size);

	find_initrd();
}
#endif

#ifdef CONFIG_SMP
#ifdef XEN
#include <asm/elf.h>

void *percpu_area __initdata = NULL;

void* __init
per_cpu_allocate(void *xen_heap_start, unsigned long end_in_pa)
{
	int order = get_order(NR_CPUS * PERCPU_PAGE_SIZE);
	unsigned long size = 1UL << (order + PAGE_SHIFT);
	unsigned long start = ALIGN_UP((unsigned long)xen_heap_start,
				       PERCPU_PAGE_SIZE);
	unsigned long end = start + size;

	if (__pa(end) < end_in_pa) {
		init_xenheap_pages(__pa(xen_heap_start), __pa(start));
		xen_heap_start = (void*)end;
		percpu_area = (void*)virt_to_xenva(start);
		printk("allocate percpu area 0x%lx@0x%lx 0x%p\n",
		       size, start, percpu_area);
	} else {
		panic("can't allocate percpu area. size 0x%lx\n", size);
	}
	return xen_heap_start;
}

static void* __init
get_per_cpu_area(void)
{
	return percpu_area;
}
#endif

/**
 * per_cpu_init - setup per-cpu variables
 *
 * Allocate and setup per-cpu data areas.
 */
void *
per_cpu_init (void)
{
	void *cpu_data;
	int cpu;

	/*
	 * get_free_pages() cannot be used before cpu_init() done.  BSP
	 * allocates "NR_CPUS" pages for all CPUs to avoid that AP calls
	 * get_zeroed_page().
	 */
	if (smp_processor_id() == 0) {
#ifdef XEN
		cpu_data = get_per_cpu_area();
		if (cpu_data == NULL) 
			panic("can't allocate per cpu area.\n");
#else
		cpu_data = __alloc_bootmem(PERCPU_PAGE_SIZE * NR_CPUS,
					   PERCPU_PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
#endif
		for (cpu = 0; cpu < NR_CPUS; cpu++) {
			memcpy(cpu_data, __phys_per_cpu_start, __per_cpu_end - __per_cpu_start);
			__per_cpu_offset[cpu] = (char *) cpu_data - __per_cpu_start;
			cpu_data += PERCPU_PAGE_SIZE;
			per_cpu(local_per_cpu_offset, cpu) = __per_cpu_offset[cpu];
		}
	}
	return __per_cpu_start + __per_cpu_offset[smp_processor_id()];
}
#endif /* CONFIG_SMP */

#ifndef XEN
static int
count_pages (u64 start, u64 end, void *arg)
{
	unsigned long *count = arg;

	*count += (end - start) >> PAGE_SHIFT;
	return 0;
}

#ifdef CONFIG_VIRTUAL_MEM_MAP
static int
count_dma_pages (u64 start, u64 end, void *arg)
{
	unsigned long *count = arg;

	if (start < MAX_DMA_ADDRESS)
		*count += (min(end, MAX_DMA_ADDRESS) - start) >> PAGE_SHIFT;
	return 0;
}
#endif

/*
 * Set up the page tables.
 */

void
paging_init (void)
{
	unsigned long max_dma;
	unsigned long zones_size[MAX_NR_ZONES];
#ifdef CONFIG_VIRTUAL_MEM_MAP
	unsigned long zholes_size[MAX_NR_ZONES];
	unsigned long max_gap;
#endif

	/* initialize mem_map[] */

	memset(zones_size, 0, sizeof(zones_size));

	num_physpages = 0;
	efi_memmap_walk(count_pages, &num_physpages);

	max_dma = virt_to_maddr((void *) MAX_DMA_ADDRESS) >> PAGE_SHIFT;

#ifdef CONFIG_VIRTUAL_MEM_MAP
	memset(zholes_size, 0, sizeof(zholes_size));

	num_dma_physpages = 0;
	efi_memmap_walk(count_dma_pages, &num_dma_physpages);

	if (max_low_pfn < max_dma) {
		zones_size[ZONE_DMA] = max_low_pfn;
		zholes_size[ZONE_DMA] = max_low_pfn - num_dma_physpages;
	} else {
		zones_size[ZONE_DMA] = max_dma;
		zholes_size[ZONE_DMA] = max_dma - num_dma_physpages;
		if (num_physpages > num_dma_physpages) {
			zones_size[ZONE_NORMAL] = max_low_pfn - max_dma;
			zholes_size[ZONE_NORMAL] =
				((max_low_pfn - max_dma) -
				 (num_physpages - num_dma_physpages));
		}
	}

	max_gap = 0;
	efi_memmap_walk(find_largest_hole, (u64 *)&max_gap);
	if (max_gap < LARGE_GAP) {
		vmem_map = (struct page *) 0;
		free_area_init_node(0, &contig_page_data, zones_size, 0,
				    zholes_size);
	} else {
		unsigned long map_size;

		/* allocate virtual_mem_map */

		map_size = PAGE_ALIGN(max_low_pfn * sizeof(struct page));
		vmalloc_end -= map_size;
		vmem_map = (struct page *) vmalloc_end;
		efi_memmap_walk(create_mem_map_page_table, NULL);

		NODE_DATA(0)->node_mem_map = vmem_map;
		free_area_init_node(0, &contig_page_data, zones_size,
				    0, zholes_size);

		printk("Virtual mem_map starts at 0x%p\n", mem_map);
	}
#else /* !CONFIG_VIRTUAL_MEM_MAP */
	if (max_low_pfn < max_dma)
		zones_size[ZONE_DMA] = max_low_pfn;
	else {
		zones_size[ZONE_DMA] = max_dma;
		zones_size[ZONE_NORMAL] = max_low_pfn - max_dma;
	}
	free_area_init(zones_size);
#endif /* !CONFIG_VIRTUAL_MEM_MAP */
	zero_page_memmap_ptr = virt_to_page(ia64_imva(empty_zero_page));
}
#endif /* XEN */