C++ PFN_UP函数代码示例

static void __init mem_prof_init(void)
{
	unsigned long start_pfn, holes, free_pfn;
	const unsigned long zone_alignment = 1UL << (MAX_ORDER - 1);
	unsigned long ul;
	mem_prof_t *mp;

	/* Node#0 SDRAM */
	mp = &mem_prof[0];
	mp->start_pfn = PFN_UP(CONFIG_MEMORY_START);
	mp->pages = PFN_DOWN(memory_end - memory_start);
	mp->holes = 0;
	mp->free_pfn = PFN_UP(__pa(_end));

	/* Node#1 internal SRAM */
	mp = &mem_prof[1];
	start_pfn = free_pfn = PFN_UP(CONFIG_IRAM_START);
	holes = 0;
	if (start_pfn & (zone_alignment - 1)) {
		ul = zone_alignment;
		while (start_pfn >= ul)
			ul += zone_alignment;

		start_pfn = ul - zone_alignment;
		holes = free_pfn - start_pfn;
	}

	mp->start_pfn = start_pfn;
	mp->pages = PFN_DOWN(CONFIG_IRAM_SIZE) + holes;
	mp->holes = holes;
	mp->free_pfn = PFN_UP(CONFIG_IRAM_START);
}

void __init bootmem_init(void)
{
	/* Reserve all memory below PHYS_OFFSET, as memory
	 * accounting doesn't work for pages below that address.
	 *
	 * If PHYS_OFFSET is zero reserve page at address 0:
	 * successfull allocations should never return NULL.
	 */
	if (PHYS_OFFSET)
		memblock_reserve(0, PHYS_OFFSET);
	else
		memblock_reserve(0, 1);

	early_init_fdt_scan_reserved_mem();

	if (!memblock_phys_mem_size())
		panic("No memory found!\n");

	min_low_pfn = PFN_UP(memblock_start_of_DRAM());
	min_low_pfn = max(min_low_pfn, PFN_UP(PHYS_OFFSET));
	max_pfn = PFN_DOWN(memblock_end_of_DRAM());
	max_low_pfn = min(max_pfn, MAX_LOW_PFN);

	memblock_set_current_limit(PFN_PHYS(max_low_pfn));
	dma_contiguous_reserve(PFN_PHYS(max_low_pfn));

	memblock_dump_all();
}

static unsigned long __init xen_set_identity_and_release(
	const struct e820entry *list, size_t map_size, unsigned long nr_pages)
{
	phys_addr_t start = 0;
	unsigned long released = 0;
	unsigned long identity = 0;
	const struct e820entry *entry;
	int i;
	int xlated_phys = xen_feature(XENFEAT_auto_translated_physmap);

	/*
	 * Combine non-RAM regions and gaps until a RAM region (or the
	 * end of the map) is reached, then set the 1:1 map and
	 * release the pages (if available) in those non-RAM regions.
	 *
	 * The combined non-RAM regions are rounded to a whole number
	 * of pages so any partial pages are accessible via the 1:1
	 * mapping.  This is needed for some BIOSes that put (for
	 * example) the DMI tables in a reserved region that begins on
	 * a non-page boundary.
	 */
	for (i = 0, entry = list; i < map_size; i++, entry++) {
		phys_addr_t end = entry->addr + entry->size;
		if (entry->type == E820_RAM || i == map_size - 1) {
			unsigned long start_pfn = PFN_DOWN(start);
			unsigned long end_pfn = PFN_UP(end);

			if (entry->type == E820_RAM)
				end_pfn = PFN_UP(entry->addr);

			if (start_pfn < end_pfn) {
				if (xlated_phys) {
					xen_pvh_adjust_stats(start_pfn,
						end_pfn, &released, &identity,
						nr_pages);
				} else {
					xen_set_identity_and_release_chunk(
						start_pfn, end_pfn, nr_pages,
						&released, &identity);
				}
			}
			start = end;
		}
	}

	if (released)
		printk(KERN_INFO "Released %lu pages of unused memory\n", released);
	if (identity)
		printk(KERN_INFO "Set %ld page(s) to 1-1 mapping\n", identity);

	return released;
}

static void __init find_limits(unsigned long *min, unsigned long *max_low,
			       unsigned long *max_high)
{
	*max_low = PFN_DOWN(memblock_get_current_limit());
	*min = PFN_UP(memblock_start_of_DRAM());
	*max_high = PFN_DOWN(memblock_end_of_DRAM());
}

/**
 * pcpu_populate_chunk - populate and map an area of a pcpu_chunk
 * @chunk: chunk of interest
 * @off: offset to the area to populate
 * @size: size of the area to populate in bytes
 *
 * For each cpu, populate and map pages [@page_start,@page_end) into
 * @chunk.  The area is cleared on return.
 *
 * CONTEXT:
 * pcpu_alloc_mutex, does GFP_KERNEL allocation.
 */
static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
{
    int page_start = PFN_DOWN(off);
    int page_end = PFN_UP(off + size);
    int free_end = page_start, unmap_end = page_start;
    struct page **pages;
    unsigned long *populated;
    unsigned int cpu;
    int rs, re, rc;

    /* quick path, check whether all pages are already there */
    rs = page_start;
    pcpu_next_pop(chunk, &rs, &re, page_end);
    if (rs == page_start && re == page_end)
        goto clear;

    /* need to allocate and map pages, this chunk can't be immutable */
    WARN_ON(chunk->immutable);

    pages = pcpu_get_pages_and_bitmap(chunk, &populated, true);
    if (!pages)
        return -ENOMEM;

    /* alloc and map */
    pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
        rc = pcpu_alloc_pages(chunk, pages, populated, rs, re);
        if (rc)
            goto err_free;
        free_end = re;
    }

void __init setup_physmem(unsigned long start, unsigned long reserve_end,
			  unsigned long len, unsigned long long highmem)
{
	unsigned long reserve = reserve_end - start;
	int pfn = PFN_UP(__pa(reserve_end));
	int delta = (len - reserve) >> PAGE_SHIFT;
	int err, offset, bootmap_size;

	physmem_fd = create_mem_file(len + highmem);

	offset = uml_reserved - uml_physmem;
	err = os_map_memory((void *) uml_reserved, physmem_fd, offset,
			    len - offset, 1, 1, 1);
	if (err < 0) {
		printf("setup_physmem - mapping %ld bytes of memory at 0x%p "
		       "failed - errno = %d\n", len - offset,
		       (void *) uml_reserved, err);
		exit(1);
	}

	/*
	 * Special kludge - This page will be mapped in to userspace processes
	 * from physmem_fd, so it needs to be written out there.
	 */
	os_seek_file(physmem_fd, __pa(&__syscall_stub_start));
	os_write_file(physmem_fd, &__syscall_stub_start, PAGE_SIZE);

	bootmap_size = init_bootmem(pfn, pfn + delta);
	free_bootmem(__pa(reserve_end) + bootmap_size,
		     len - bootmap_size - reserve);
}

static unsigned long __init xen_count_remap_pages(unsigned long max_pfn)
{
	unsigned long extra = 0;
	unsigned long start_pfn, end_pfn;
	const struct e820entry *entry = xen_e820_map;
	int i;

	end_pfn = 0;
	for (i = 0; i < xen_e820_map_entries; i++, entry++) {
		start_pfn = PFN_DOWN(entry->addr);
		/* Adjacent regions on non-page boundaries handling! */
		end_pfn = min(end_pfn, start_pfn);

		if (start_pfn >= max_pfn)
			return extra + max_pfn - end_pfn;

		/* Add any holes in map to result. */
		extra += start_pfn - end_pfn;

		end_pfn = PFN_UP(entry->addr + entry->size);
		end_pfn = min(end_pfn, max_pfn);

		if (entry->type != E820_RAM)
			extra += end_pfn - start_pfn;
	}

	return extra;
}

static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
{
	int page_start = PFN_DOWN(off);
	int page_end = PFN_UP(off + size);
	int free_end = page_start, unmap_end = page_start;
	struct page **pages;
	unsigned long *populated;
	unsigned int cpu;
	int rs, re, rc;

	
	rs = page_start;
	pcpu_next_pop(chunk, &rs, &re, page_end);
	if (rs == page_start && re == page_end)
		goto clear;

	
	WARN_ON(chunk->immutable);

	pages = pcpu_get_pages_and_bitmap(chunk, &populated, true);
	if (!pages)
		return -ENOMEM;

	
	pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
		rc = pcpu_alloc_pages(chunk, pages, populated, rs, re);
		if (rc)
			goto err_free;
		free_end = re;
	}

/*
 * Finds the next RAM pfn available in the E820 map after min_pfn.
 * This function updates min_pfn with the pfn found and returns
 * the size of that range or zero if not found.
 */
static unsigned long __init xen_find_pfn_range(unsigned long *min_pfn)
{
	const struct e820entry *entry = xen_e820_map;
	unsigned int i;
	unsigned long done = 0;

	for (i = 0; i < xen_e820_map_entries; i++, entry++) {
		unsigned long s_pfn;
		unsigned long e_pfn;

		if (entry->type != E820_RAM)
			continue;

		e_pfn = PFN_DOWN(entry->addr + entry->size);

		/* We only care about E820 after this */
		if (e_pfn <= *min_pfn)
			continue;

		s_pfn = PFN_UP(entry->addr);

		/* If min_pfn falls within the E820 entry, we want to start
		 * at the min_pfn PFN.
		 */
		if (s_pfn <= *min_pfn) {
			done = e_pfn - *min_pfn;
		} else {
			done = e_pfn - s_pfn;
			*min_pfn = s_pfn;
		}
		break;
	}

	return done;
}

static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size)
{
	int page_start = PFN_DOWN(off);
	int page_end = PFN_UP(off + size);
	struct page **pages;
	unsigned long *populated;
	int rs, re;

	
	rs = page_start;
	pcpu_next_unpop(chunk, &rs, &re, page_end);
	if (rs == page_start && re == page_end)
		return;

	
	WARN_ON(chunk->immutable);

	pages = pcpu_get_pages_and_bitmap(chunk, &populated, false);
	BUG_ON(!pages);

	
	pcpu_pre_unmap_flush(chunk, page_start, page_end);

	pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
		pcpu_unmap_pages(chunk, pages, populated, rs, re);

	

	pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
		pcpu_free_pages(chunk, pages, populated, rs, re);

	
	bitmap_copy(chunk->populated, populated, pcpu_unit_pages);
}

int pfn_is_nosave(unsigned long pfn)
{
	unsigned long nosave_begin_pfn = PFN_DOWN(__pa(&__nosave_begin));
	unsigned long nosave_end_pfn = PFN_UP(__pa(&__nosave_end));

	return	(pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
}

void __init tboot_probe(void)
{
    tboot_shared_t *tboot_shared;
    unsigned long p_tboot_shared;
    uint32_t map_base, map_size;
    unsigned long map_addr;

    /* Look for valid page-aligned address for shared page. */
    p_tboot_shared = simple_strtoul(opt_tboot, NULL, 0);
    if ( (p_tboot_shared == 0) || ((p_tboot_shared & ~PAGE_MASK) != 0) )
        return;

    /* Map and check for tboot UUID. */
    set_fixmap(FIX_TBOOT_SHARED_BASE, p_tboot_shared);
    tboot_shared = (tboot_shared_t *)fix_to_virt(FIX_TBOOT_SHARED_BASE);
    if ( tboot_shared == NULL )
        return;
    if ( memcmp(&tboot_shared_uuid, (uuid_t *)tboot_shared, sizeof(uuid_t)) )
        return;

    /* new tboot_shared (w/ GAS support, integrity, etc.) is not backwards
       compatible */
    if ( tboot_shared->version < 4 ) {
        printk("unsupported version of tboot (%u)\n", tboot_shared->version);
        return;
    }

    g_tboot_shared = tboot_shared;
    printk("TBOOT: found shared page at phys addr %lx:\n", p_tboot_shared);
    printk("  version: %d\n", tboot_shared->version);
    printk("  log_addr: 0x%08x\n", tboot_shared->log_addr);
    printk("  shutdown_entry: 0x%08x\n", tboot_shared->shutdown_entry);
    printk("  tboot_base: 0x%08x\n", tboot_shared->tboot_base);
    printk("  tboot_size: 0x%x\n", tboot_shared->tboot_size);

    /* these will be needed by tboot_protect_mem_regions() and/or
       tboot_parse_dmar_table(), so get them now */

    map_base = PFN_DOWN(TXT_PUB_CONFIG_REGS_BASE);
    map_size = PFN_UP(NR_TXT_CONFIG_PAGES * PAGE_SIZE);
    map_addr = (unsigned long)__va(map_base << PAGE_SHIFT);
    if ( map_pages_to_xen(map_addr, map_base, map_size, __PAGE_HYPERVISOR) )
        return;

    /* TXT Heap */
    txt_heap_base =
        *(uint64_t *)__va(TXT_PUB_CONFIG_REGS_BASE + TXTCR_HEAP_BASE);
    txt_heap_size =
        *(uint64_t *)__va(TXT_PUB_CONFIG_REGS_BASE + TXTCR_HEAP_SIZE);

    /* SINIT */
    sinit_base =
        *(uint64_t *)__va(TXT_PUB_CONFIG_REGS_BASE + TXTCR_SINIT_BASE);
    sinit_size =
        *(uint64_t *)__va(TXT_PUB_CONFIG_REGS_BASE + TXTCR_SINIT_SIZE);

    destroy_xen_mappings((unsigned long)__va(map_base << PAGE_SHIFT),
                         (unsigned long)__va((map_base + map_size) << PAGE_SHIFT));
}

static u64 __init mem_hole_size(u64 start, u64 end)
{
	unsigned long start_pfn = PFN_UP(start);
	unsigned long end_pfn = PFN_DOWN(end);

	if (start_pfn < end_pfn)
		return PFN_PHYS(absent_pages_in_range(start_pfn, end_pfn));
	return 0;
}

/* it returns the next free pfn after initrd */
static unsigned long __init init_initrd(void)
{
	unsigned long end;

	/*
	 * Board specific code or command line parser should have
	 * already set up initrd_start and initrd_end. In these cases
	 * perfom sanity checks and use them if all looks good.
	 */
	if (!initrd_start || initrd_end <= initrd_start) {
#ifdef CONFIG_PROBE_INITRD_HEADER
		u32 *initrd_header;

		/*
		 * See if initrd has been added to the kernel image by
		 * arch/mips/boot/addinitrd.c. In that case a header is
		 * prepended to initrd and is made up by 8 bytes. The first
		 * word is a magic number and the second one is the size of
		 * initrd.  Initrd start must be page aligned in any cases.
		 */
		initrd_header = __va(PAGE_ALIGN(__pa_symbol(&_end) + 8)) - 8;
		if (initrd_header[0] != 0x494E5244)
			goto disable;
		initrd_start = (unsigned long)(initrd_header + 2);
		initrd_end = initrd_start + initrd_header[1];
#else
		goto disable;
#endif
	}

	if (initrd_start & ~PAGE_MASK) {
		pr_err("initrd start must be page aligned\n");
		goto disable;
	}
	if (initrd_start < PAGE_OFFSET) {
		pr_err("initrd start < PAGE_OFFSET\n");
		goto disable;
	}

	/*
	 * Sanitize initrd addresses. For example firmware
	 * can't guess if they need to pass them through
	 * 64-bits values if the kernel has been built in pure
	 * 32-bit. We need also to switch from KSEG0 to XKPHYS
	 * addresses now, so the code can now safely use __pa().
	 */
	end = __pa(initrd_end);
	initrd_end = (unsigned long)__va(end);
	initrd_start = (unsigned long)__va(__pa(initrd_start));

	ROOT_DEV = Root_RAM0;
	return PFN_UP(end);
disable:
	initrd_start = 0;
	initrd_end = 0;
	return 0;
}

static void __init bootmem_init(void)
{
	unsigned long start_pfn, bootmap_size;
	unsigned long size = initrd_end - initrd_start;

	start_pfn = PFN_UP(__pa(&_end));

	min_low_pfn = PFN_UP(MEMORY_START);
	max_low_pfn = PFN_UP(MEMORY_START + MEMORY_SIZE);

	/* Initialize the boot-time allocator with low memory only. */
	bootmap_size = init_bootmem_node(NODE_DATA(0), start_pfn,
					 min_low_pfn, max_low_pfn);
	add_active_range(0, min_low_pfn, max_low_pfn);

	free_bootmem(PFN_PHYS(start_pfn),
		     (max_low_pfn - start_pfn) << PAGE_SHIFT);
	memory_present(0, start_pfn, max_low_pfn);

	/* Reserve space for the bootmem bitmap. */
	reserve_bootmem(PFN_PHYS(start_pfn), bootmap_size, BOOTMEM_DEFAULT);

	if (size == 0) {
		printk(KERN_INFO "Initrd not found or empty");
		goto disable;
	}

	if (__pa(initrd_end) > PFN_PHYS(max_low_pfn)) {
		printk(KERN_ERR "Initrd extends beyond end of memory");
		goto disable;
	}

	/* Reserve space for the initrd bitmap. */
	reserve_bootmem(__pa(initrd_start), size, BOOTMEM_DEFAULT);
	initrd_below_start_ok = 1;

	pr_info("Initial ramdisk at: 0x%lx (%lu bytes)\n",
		 initrd_start, size);
	return;
disable:
	printk(KERN_CONT " - disabling initrd\n");
	initrd_start = 0;
	initrd_end = 0;
}