// SPDX-License-Identifier: GPL-2.0
/*
 * Bootmem core functions.
 *
 * Copyright (c) 2020, Bytedance.
 *
 *     Author: Muchun Song <songmuchun@bytedance.com>
 *
 */
#include <linux/mm.h>
#include <linux/compiler.h>
#include <linux/memblock.h>
#include <linux/bootmem_info.h>
#include <linux/memory_hotplug.h>
#include <linux/kmemleak.h>

void get_page_bootmem(unsigned long info, struct page *page,
                enum bootmem_type type)
{
        BUG_ON(type > 0xf);
        BUG_ON(info > (ULONG_MAX >> 4));
        SetPagePrivate(page);
        set_page_private(page, info << 4 | type);
        page_ref_inc(page);
}

void put_page_bootmem(struct page *page)
{
        enum bootmem_type type = bootmem_type(page);

        BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
               type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);

        if (page_ref_dec_return(page) == 1) {
                ClearPagePrivate(page);
                set_page_private(page, 0);
                INIT_LIST_HEAD(&page->lru);
                kmemleak_free_part_phys(PFN_PHYS(page_to_pfn(page)), PAGE_SIZE);
                free_reserved_page(page);
        }
}

#ifndef CONFIG_SPARSEMEM_VMEMMAP
static void __init register_page_bootmem_info_section(unsigned long start_pfn)
{
        unsigned long mapsize, section_nr, i;
        struct mem_section *ms;
        struct page *page, *memmap;
        struct mem_section_usage *usage;

        section_nr = pfn_to_section_nr(start_pfn);
        ms = __nr_to_section(section_nr);

        /* Get section's memmap address */
        memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);

        /*
         * Get page for the memmap's phys address
         * XXX: need more consideration for sparse_vmemmap...
         */
        page = virt_to_page(memmap);
        mapsize = sizeof(struct page) * PAGES_PER_SECTION;
        mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;

        /* remember memmap's page */
        for (i = 0; i < mapsize; i++, page++)
                get_page_bootmem(section_nr, page, SECTION_INFO);

        usage = ms->usage;
        page = virt_to_page(usage);

        mapsize = PAGE_ALIGN(mem_section_usage_size()) >> PAGE_SHIFT;

        for (i = 0; i < mapsize; i++, page++)
                get_page_bootmem(section_nr, page, MIX_SECTION_INFO);

}
#else /* CONFIG_SPARSEMEM_VMEMMAP */
static void __init register_page_bootmem_info_section(unsigned long start_pfn)
{
        unsigned long mapsize, section_nr, i;
        struct mem_section *ms;
        struct page *page, *memmap;
        struct mem_section_usage *usage;

        section_nr = pfn_to_section_nr(start_pfn);
        ms = __nr_to_section(section_nr);

        memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);

        if (!preinited_vmemmap_section(ms))
                register_page_bootmem_memmap(section_nr, memmap,
                                PAGES_PER_SECTION);

        usage = ms->usage;
        page = virt_to_page(usage);

        mapsize = PAGE_ALIGN(mem_section_usage_size()) >> PAGE_SHIFT;

        for (i = 0; i < mapsize; i++, page++)
                get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
}
#endif /* !CONFIG_SPARSEMEM_VMEMMAP */

void __init register_page_bootmem_info_node(struct pglist_data *pgdat)
{
        unsigned long i, pfn, end_pfn, nr_pages;
        int node = pgdat->node_id;
        struct page *page;

        nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
        page = virt_to_page(pgdat);

        for (i = 0; i < nr_pages; i++, page++)
                get_page_bootmem(node, page, NODE_INFO);

        pfn = pgdat->node_start_pfn;
        end_pfn = pgdat_end_pfn(pgdat);

        /* register section info */
        for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
                /*
                 * Some platforms can assign the same pfn to multiple nodes - on
                 * node0 as well as nodeN.  To avoid registering a pfn against
                 * multiple nodes we check that this pfn does not already
                 * reside in some other nodes.
                 */
                if (pfn_valid(pfn) && (early_pfn_to_nid(pfn) == node))
                        register_page_bootmem_info_section(pfn);
        }
}