1. 根目录:
2. arch
3. ia64
4. mm
5. contig.c

/*
 * 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 <davidm@hpl.hp.com>
 *	Stephane Eranian <eranian@hpl.hp.com>
 * Copyright (C) 2000, Rohit Seth <rohit.seth@intel.com>
 * Copyright (C) 1999 VA Linux Systems
 * Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
 * Copyright (C) 2003 Silicon Graphics, Inc. All rights reserved.
 *
 * Routines used by ia64 machines with contiguous (or virtually contiguous)
 * memory.
 */
#include <linux/bootmem.h>
#include <linux/efi.h>
#include <linux/memblock.h>
#include <linux/mm.h>
#include <linux/nmi.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>

#ifdef CONFIG_VIRTUAL_MEM_MAP
static unsigned long max_gap;
#endif

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

/**
 * 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.
 */
static int __init
find_bootmap_location (u64 start, u64 end, void *arg)
{
	u64 needed = *(unsigned long *)arg;
	u64 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;
}

#ifdef CONFIG_SMP
static void *cpu_data;
/**
 * per_cpu_init - setup per-cpu variables
 *
 * Allocate and setup per-cpu data areas.
 */
void *per_cpu_init(void)
{
	static bool first_time = true;
	void *cpu0_data = __cpu0_per_cpu;
	unsigned int cpu;

	if (!first_time)
		goto skip;
	first_time = false;

	/*
	 * get_free_pages() cannot be used before cpu_init() done.
	 * BSP allocates PERCPU_PAGE_SIZE bytes for all possible CPUs
	 * to avoid that AP calls get_zeroed_page().
	 */
	for_each_possible_cpu(cpu) {
		void *src = cpu == 0 ? cpu0_data : __phys_per_cpu_start;

		memcpy(cpu_data, src, __per_cpu_end - __per_cpu_start);
		__per_cpu_offset[cpu] = (char *)cpu_data - __per_cpu_start;
		per_cpu(local_per_cpu_offset, cpu) = __per_cpu_offset[cpu];

		/*
		 * percpu area for cpu0 is moved from the __init area
		 * which is setup by head.S and used till this point.
		 * Update ar.k3.  This move is ensures that percpu
		 * area for cpu0 is on the correct node and its
		 * virtual address isn't insanely far from other
		 * percpu areas which is important for congruent
		 * percpu allocator.
		 */
		if (cpu == 0)
			ia64_set_kr(IA64_KR_PER_CPU_DATA, __pa(cpu_data) -
				    (unsigned long)__per_cpu_start);

		cpu_data += PERCPU_PAGE_SIZE;
	}
skip:
	return __per_cpu_start + __per_cpu_offset[smp_processor_id()];
}

static inline void
alloc_per_cpu_data(void)
{
	cpu_data = __alloc_bootmem(PERCPU_PAGE_SIZE * num_possible_cpus(),
				   PERCPU_PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
}

/**
 * setup_per_cpu_areas - setup percpu areas
 *
 * Arch code has already allocated and initialized percpu areas.  All
 * this function has to do is to teach the determined layout to the
 * dynamic percpu allocator, which happens to be more complex than
 * creating whole new ones using helpers.
 */
void __init
setup_per_cpu_areas(void)
{
	struct pcpu_alloc_info *ai;
	struct pcpu_group_info *gi;
	unsigned int cpu;
	ssize_t static_size, reserved_size, dyn_size;
	int rc;

	ai = pcpu_alloc_alloc_info(1, num_possible_cpus());
	if (!ai)
		panic("failed to allocate pcpu_alloc_info");
	gi = &ai->groups[0];

	/* units are assigned consecutively to possible cpus */
	for_each_possible_cpu(cpu)
		gi->cpu_map[gi->nr_units++] = cpu;

	/* set parameters */
	static_size = __per_cpu_end - __per_cpu_start;
	reserved_size = PERCPU_MODULE_RESERVE;
	dyn_size = PERCPU_PAGE_SIZE - static_size - reserved_size;
	if (dyn_size < 0)
		panic("percpu area overflow static=%zd reserved=%zd\n",
		      static_size, reserved_size);

	ai->static_size		= static_size;
	ai->reserved_size	= reserved_size;
	ai->dyn_size		= dyn_size;
	ai->unit_size		= PERCPU_PAGE_SIZE;
	ai->atom_size		= PAGE_SIZE;
	ai->alloc_size		= PERCPU_PAGE_SIZE;

	rc = pcpu_setup_first_chunk(ai, __per_cpu_start + __per_cpu_offset[0]);
	if (rc)
		panic("failed to setup percpu area (err=%d)", rc);

	pcpu_free_alloc_info(ai);
}
#else
#define alloc_per_cpu_data() do { } while (0)
#endif /* CONFIG_SMP */

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

	reserve_memory();

	/* first find highest page frame number */
	min_low_pfn = ~0UL;
	max_low_pfn = 0;
	efi_memmap_walk(find_max_min_low_pfn, NULL);
	max_pfn = max_low_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_node(NODE_DATA(0),
			(bootmap_start >> PAGE_SHIFT), 0, 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, BOOTMEM_DEFAULT);

	find_initrd();

	alloc_per_cpu_data();
}

/*
 * Set up the page tables.
 */

void __init
paging_init (void)
{
	unsigned long max_dma;
	unsigned long max_zone_pfns[MAX_NR_ZONES];

	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
#ifdef CONFIG_ZONE_DMA
	max_dma = virt_to_phys((void *) MAX_DMA_ADDRESS) >> PAGE_SHIFT;
	max_zone_pfns[ZONE_DMA] = max_dma;
#endif
	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;

#ifdef CONFIG_VIRTUAL_MEM_MAP
	efi_memmap_walk(filter_memory, register_active_ranges);
	efi_memmap_walk(find_largest_hole, (u64 *)&max_gap);
	if (max_gap < LARGE_GAP) {
		vmem_map = (struct page *) 0;
		free_area_init_nodes(max_zone_pfns);
	} else {
		unsigned long map_size;

		/* allocate virtual_mem_map */

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

		/*
		 * alloc_node_mem_map makes an adjustment for mem_map
		 * which isn't compatible with vmem_map.
		 */
		NODE_DATA(0)->node_mem_map = vmem_map +
			find_min_pfn_with_active_regions();
		free_area_init_nodes(max_zone_pfns);

		printk("Virtual mem_map starts at 0x%p\n", mem_map);
	}
#else /* !CONFIG_VIRTUAL_MEM_MAP */
	memblock_add_node(0, PFN_PHYS(max_low_pfn), 0);
	free_area_init_nodes(max_zone_pfns);
#endif /* !CONFIG_VIRTUAL_MEM_MAP */
	zero_page_memmap_ptr = virt_to_page(ia64_imva(empty_zero_page));
}