1. 根目录:
2. arch
3. unicore32
4. mm
5. init.c

/*
 *  linux/arch/unicore32/mm/init.c
 *
 *  Copyright (C) 2010 GUAN Xue-tao
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/swap.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/mman.h>
#include <linux/nodemask.h>
#include <linux/initrd.h>
#include <linux/highmem.h>
#include <linux/gfp.h>
#include <linux/memblock.h>
#include <linux/sort.h>
#include <linux/dma-mapping.h>
#include <linux/export.h>

#include <asm/sections.h>
#include <asm/setup.h>
#include <asm/sizes.h>
#include <asm/tlb.h>
#include <asm/memblock.h>
#include <mach/map.h>

#include "mm.h"

static unsigned long phys_initrd_start __initdata = 0x01000000;
static unsigned long phys_initrd_size __initdata = SZ_8M;

static int __init early_initrd(char *p)
{
	unsigned long start, size;
	char *endp;

	start = memparse(p, &endp);
	if (*endp == ',') {
		size = memparse(endp + 1, NULL);

		phys_initrd_start = start;
		phys_initrd_size = size;
	}
	return 0;
}
early_param("initrd", early_initrd);

/*
 * This keeps memory configuration data used by a couple memory
 * initialization functions, as well as show_mem() for the skipping
 * of holes in the memory map.  It is populated by uc32_add_memory().
 */
struct meminfo meminfo;

void show_mem(unsigned int filter)
{
	int free = 0, total = 0, reserved = 0;
	int shared = 0, cached = 0, slab = 0, i;
	struct meminfo *mi = &meminfo;

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

	for_each_bank(i, mi) {
		struct membank *bank = &mi->bank[i];
		unsigned int pfn1, pfn2;
		struct page *page, *end;

		pfn1 = bank_pfn_start(bank);
		pfn2 = bank_pfn_end(bank);

		page = pfn_to_page(pfn1);
		end  = pfn_to_page(pfn2 - 1) + 1;

		do {
			total++;
			if (PageReserved(page))
				reserved++;
			else if (PageSwapCache(page))
				cached++;
			else if (PageSlab(page))
				slab++;
			else if (!page_count(page))
				free++;
			else
				shared += page_count(page) - 1;
			page++;
		} while (page < end);
	}

	printk(KERN_DEFAULT "%d pages of RAM\n", total);
	printk(KERN_DEFAULT "%d free pages\n", free);
	printk(KERN_DEFAULT "%d reserved pages\n", reserved);
	printk(KERN_DEFAULT "%d slab pages\n", slab);
	printk(KERN_DEFAULT "%d pages shared\n", shared);
	printk(KERN_DEFAULT "%d pages swap cached\n", cached);
}

static void __init find_limits(unsigned long *min, unsigned long *max_low,
	unsigned long *max_high)
{
	struct meminfo *mi = &meminfo;
	int i;

	*min = -1UL;
	*max_low = *max_high = 0;

	for_each_bank(i, mi) {
		struct membank *bank = &mi->bank[i];
		unsigned long start, end;

		start = bank_pfn_start(bank);
		end = bank_pfn_end(bank);

		if (*min > start)
			*min = start;
		if (*max_high < end)
			*max_high = end;
		if (bank->highmem)
			continue;
		if (*max_low < end)
			*max_low = end;
	}
}

static void __init uc32_bootmem_init(unsigned long start_pfn,
	unsigned long end_pfn)
{
	struct memblock_region *reg;
	unsigned int boot_pages;
	phys_addr_t bitmap;
	pg_data_t *pgdat;

	/*
	 * Allocate the bootmem bitmap page.  This must be in a region
	 * of memory which has already been mapped.
	 */
	boot_pages = bootmem_bootmap_pages(end_pfn - start_pfn);
	bitmap = memblock_alloc_base(boot_pages << PAGE_SHIFT, L1_CACHE_BYTES,
				__pfn_to_phys(end_pfn));

	/*
	 * Initialise the bootmem allocator, handing the
	 * memory banks over to bootmem.
	 */
	node_set_online(0);
	pgdat = NODE_DATA(0);
	init_bootmem_node(pgdat, __phys_to_pfn(bitmap), start_pfn, end_pfn);

	/* Free the lowmem regions from memblock into bootmem. */
	for_each_memblock(memory, reg) {
		unsigned long start = memblock_region_memory_base_pfn(reg);
		unsigned long end = memblock_region_memory_end_pfn(reg);

		if (end >= end_pfn)
			end = end_pfn;
		if (start >= end)
			break;

		free_bootmem(__pfn_to_phys(start), (end - start) << PAGE_SHIFT);
	}

	/* Reserve the lowmem memblock reserved regions in bootmem. */
	for_each_memblock(reserved, reg) {
		unsigned long start = memblock_region_reserved_base_pfn(reg);
		unsigned long end = memblock_region_reserved_end_pfn(reg);

		if (end >= end_pfn)
			end = end_pfn;
		if (start >= end)
			break;

		reserve_bootmem(__pfn_to_phys(start),
			(end - start) << PAGE_SHIFT, BOOTMEM_DEFAULT);
	}
}

static void __init uc32_bootmem_free(unsigned long min, unsigned long max_low,
	unsigned long max_high)
{
	unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
	struct memblock_region *reg;

	/*
	 * initialise the zones.
	 */
	memset(zone_size, 0, sizeof(zone_size));

	/*
	 * The memory size has already been determined.  If we need
	 * to do anything fancy with the allocation of this memory
	 * to the zones, now is the time to do it.
	 */
	zone_size[0] = max_low - min;

	/*
	 * Calculate the size of the holes.
	 *  holes = node_size - sum(bank_sizes)
	 */
	memcpy(zhole_size, zone_size, sizeof(zhole_size));
	for_each_memblock(memory, reg) {
		unsigned long start = memblock_region_memory_base_pfn(reg);
		unsigned long end = memblock_region_memory_end_pfn(reg);

		if (start < max_low) {
			unsigned long low_end = min(end, max_low);
			zhole_size[0] -= low_end - start;
		}
	}

	/*
	 * Adjust the sizes according to any special requirements for
	 * this machine type.
	 */
	arch_adjust_zones(zone_size, zhole_size);

	free_area_init_node(0, zone_size, min, zhole_size);
}

int pfn_valid(unsigned long pfn)
{
	return memblock_is_memory(pfn << PAGE_SHIFT);
}
EXPORT_SYMBOL(pfn_valid);

static void uc32_memory_present(void)
{
}

static int __init meminfo_cmp(const void *_a, const void *_b)
{
	const struct membank *a = _a, *b = _b;
	long cmp = bank_pfn_start(a) - bank_pfn_start(b);
	return cmp < 0 ? -1 : cmp > 0 ? 1 : 0;
}

void __init uc32_memblock_init(struct meminfo *mi)
{
	int i;

	sort(&meminfo.bank, meminfo.nr_banks, sizeof(meminfo.bank[0]),
		meminfo_cmp, NULL);

	for (i = 0; i < mi->nr_banks; i++)
		memblock_add(mi->bank[i].start, mi->bank[i].size);

	/* Register the kernel text, kernel data and initrd with memblock. */
	memblock_reserve(__pa(_text), _end - _text);

#ifdef CONFIG_BLK_DEV_INITRD
	if (phys_initrd_size) {
		memblock_reserve(phys_initrd_start, phys_initrd_size);

		/* Now convert initrd to virtual addresses */
		initrd_start = __phys_to_virt(phys_initrd_start);
		initrd_end = initrd_start + phys_initrd_size;
	}
#endif

	uc32_mm_memblock_reserve();

	memblock_allow_resize();
	memblock_dump_all();
}

void __init bootmem_init(void)
{
	unsigned long min, max_low, max_high;

	max_low = max_high = 0;

	find_limits(&min, &max_low, &max_high);

	uc32_bootmem_init(min, max_low);

#ifdef CONFIG_SWIOTLB
	swiotlb_init(1);
#endif
	/*
	 * Sparsemem tries to allocate bootmem in memory_present(),
	 * so must be done after the fixed reservations
	 */
	uc32_memory_present();

	/*
	 * sparse_init() needs the bootmem allocator up and running.
	 */
	sparse_init();

	/*
	 * Now free the memory - free_area_init_node needs
	 * the sparse mem_map arrays initialized by sparse_init()
	 * for memmap_init_zone(), otherwise all PFNs are invalid.
	 */
	uc32_bootmem_free(min, max_low, max_high);

	high_memory = __va((max_low << PAGE_SHIFT) - 1) + 1;

	/*
	 * This doesn't seem to be used by the Linux memory manager any
	 * more, but is used by ll_rw_block.  If we can get rid of it, we
	 * also get rid of some of the stuff above as well.
	 *
	 * Note: max_low_pfn and max_pfn reflect the number of _pages_ in
	 * the system, not the maximum PFN.
	 */
	max_low_pfn = max_low - PHYS_PFN_OFFSET;
	max_pfn = max_high - PHYS_PFN_OFFSET;
}

static inline void
free_memmap(unsigned long start_pfn, unsigned long end_pfn)
{
	struct page *start_pg, *end_pg;
	unsigned long pg, pgend;

	/*
	 * Convert start_pfn/end_pfn to a struct page pointer.
	 */
	start_pg = pfn_to_page(start_pfn - 1) + 1;
	end_pg = pfn_to_page(end_pfn);

	/*
	 * Convert to physical addresses, and
	 * round start upwards and end downwards.
	 */
	pg = PAGE_ALIGN(__pa(start_pg));
	pgend = __pa(end_pg) & PAGE_MASK;

	/*
	 * If there are free pages between these,
	 * free the section of the memmap array.
	 */
	if (pg < pgend)
		free_bootmem(pg, pgend - pg);
}

/*
 * The mem_map array can get very big.  Free the unused area of the memory map.
 */
static void __init free_unused_memmap(struct meminfo *mi)
{
	unsigned long bank_start, prev_bank_end = 0;
	unsigned int i;

	/*
	 * This relies on each bank being in address order.
	 * The banks are sorted previously in bootmem_init().
	 */
	for_each_bank(i, mi) {
		struct membank *bank = &mi->bank[i];

		bank_start = bank_pfn_start(bank);

		/*
		 * If we had a previous bank, and there is a space
		 * between the current bank and the previous, free it.
		 */
		if (prev_bank_end && prev_bank_end < bank_start)
			free_memmap(prev_bank_end, bank_start);

		/*
		 * Align up here since the VM subsystem insists that the
		 * memmap entries are valid from the bank end aligned to
		 * MAX_ORDER_NR_PAGES.
		 */
		prev_bank_end = ALIGN(bank_pfn_end(bank), MAX_ORDER_NR_PAGES);
	}
}

/*
 * mem_init() marks the free areas in the mem_map and tells us how much
 * memory is free.  This is done after various parts of the system have
 * claimed their memory after the kernel image.
 */
void __init mem_init(void)
{
	max_mapnr   = pfn_to_page(max_pfn + PHYS_PFN_OFFSET) - mem_map;

	free_unused_memmap(&meminfo);

	/* this will put all unused low memory onto the freelists */
	free_all_bootmem();

	mem_init_print_info(NULL);
	printk(KERN_NOTICE "Virtual kernel memory layout:\n"
		"    vector  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
		"    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
		"    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
		"    modules : 0x%08lx - 0x%08lx   (%4ld MB)\n"
		"      .init : 0x%p" " - 0x%p" "   (%4d kB)\n"
		"      .text : 0x%p" " - 0x%p" "   (%4d kB)\n"
		"      .data : 0x%p" " - 0x%p" "   (%4d kB)\n",

		VECTORS_BASE, VECTORS_BASE + PAGE_SIZE,
		DIV_ROUND_UP(PAGE_SIZE, SZ_1K),
		VMALLOC_START, VMALLOC_END,
		DIV_ROUND_UP((VMALLOC_END - VMALLOC_START), SZ_1M),
		PAGE_OFFSET, (unsigned long)high_memory,
		DIV_ROUND_UP(((unsigned long)high_memory - PAGE_OFFSET), SZ_1M),
		MODULES_VADDR, MODULES_END,
		DIV_ROUND_UP((MODULES_END - MODULES_VADDR), SZ_1M),

		__init_begin, __init_end,
		DIV_ROUND_UP((__init_end - __init_begin), SZ_1K),
		_stext, _etext,
		DIV_ROUND_UP((_etext - _stext), SZ_1K),
		_sdata, _edata,
		DIV_ROUND_UP((_edata - _sdata), SZ_1K));

	BUILD_BUG_ON(TASK_SIZE				> MODULES_VADDR);
	BUG_ON(TASK_SIZE				> MODULES_VADDR);

	if (PAGE_SIZE >= 16384 && get_num_physpages() <= 128) {
		/*
		 * On a machine this small we won't get
		 * anywhere without overcommit, so turn
		 * it on by default.
		 */
		sysctl_overcommit_memory = OVERCOMMIT_ALWAYS;
	}
}

void free_initmem(void)
{
	free_initmem_default(-1);
}

#ifdef CONFIG_BLK_DEV_INITRD

static int keep_initrd;

void free_initrd_mem(unsigned long start, unsigned long end)
{
	if (!keep_initrd)
		free_reserved_area((void *)start, (void *)end, -1, "initrd");
}

static int __init keepinitrd_setup(char *__unused)
{
	keep_initrd = 1;
	return 1;
}

__setup("keepinitrd", keepinitrd_setup);
#endif