init.c

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/*
 * Based on arch/arm/mm/init.c
 *
 * Copyright (C) 1995-2005 Russell King
 * Copyright (C) 2012 ARM Ltd.
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/kernel.h>
#include <linux/export.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/gfp.h>
#include <linux/memblock.h>
#include <linux/sort.h>
#include <linux/of_fdt.h>

#include <asm/prom.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include <asm/sizes.h>
#include <asm/tlb.h>

#include "mm.h"

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

phys_addr_t memstart_addr __read_mostly = 0;

void __init early_init_dt_setup_initrd_arch(unsigned long start,
                        unsigned long end)
{
    phys_initrd_start = start;
    phys_initrd_size = end - start;
}

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);

#define MAX_DMA32_PFN ((4UL * 1024 * 1024 * 1024) >> PAGE_SHIFT)

static void __init zone_sizes_init(unsigned long min, unsigned long max)
{
    struct memblock_region *reg;
    unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
    unsigned long max_dma32 = min;

    memset(zone_size, 0, sizeof(zone_size));

#ifdef CONFIG_ZONE_DMA32
    /* 4GB maximum for 32-bit only capable devices */
    max_dma32 = min(max, MAX_DMA32_PFN);
    zone_size[ZONE_DMA32] = max(min, max_dma32) - min;
#endif
    zone_size[ZONE_NORMAL] = max - max_dma32;

    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)
            continue;
#ifdef CONFIG_ZONE_DMA32
        if (start < max_dma32) {
            unsigned long dma_end = min(end, max_dma32);
            zhole_size[ZONE_DMA32] -= dma_end - start;
        }
#endif
        if (end > max_dma32) {
            unsigned long normal_end = min(end, max);
            unsigned long normal_start = max(start, max_dma32);
            zhole_size[ZONE_NORMAL] -= normal_end - normal_start;
        }
    }

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

#ifdef CONFIG_HAVE_ARCH_PFN_VALID
int pfn_valid(unsigned long pfn)
{
    return memblock_is_memory(pfn << PAGE_SHIFT);
}
EXPORT_SYMBOL(pfn_valid);
#endif

#ifndef CONFIG_SPARSEMEM
static void arm64_memory_present(void)
{
}
#else
static void arm64_memory_present(void)
{
    struct memblock_region *reg;

    for_each_memblock(memory, reg)
        memory_present(0, memblock_region_memory_base_pfn(reg),
                   memblock_region_memory_end_pfn(reg));
}
#endif

void __init arm64_memblock_init(void)
{
    u64 *reserve_map, base, 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

    /*
     * Reserve the page tables.  These are already in use,
     * and can only be in node 0.
     */
    memblock_reserve(__pa(swapper_pg_dir), SWAPPER_DIR_SIZE);
    memblock_reserve(__pa(idmap_pg_dir), IDMAP_DIR_SIZE);

    /* Reserve the dtb region */
    memblock_reserve(virt_to_phys(initial_boot_params),
             be32_to_cpu(initial_boot_params->totalsize));

    /*
     * Process the reserve map.  This will probably overlap the initrd
     * and dtb locations which are already reserved, but overlapping
     * doesn't hurt anything
     */
    reserve_map = ((void*)initial_boot_params) +
            be32_to_cpu(initial_boot_params->off_mem_rsvmap);
    while (1) {
        base = be64_to_cpup(reserve_map++);
        size = be64_to_cpup(reserve_map++);
        if (!size)
            break;
        memblock_reserve(base, size);
    }

    memblock_allow_resize();
    memblock_dump_all();
}

void __init bootmem_init(void)
{
    unsigned long min, max;

    min = PFN_UP(memblock_start_of_DRAM());
    max = PFN_DOWN(memblock_end_of_DRAM());

    /*
     * Sparsemem tries to allocate bootmem in memory_present(), so must be
     * done after the fixed reservations.
     */
    arm64_memory_present();

    sparse_init();
    zone_sizes_init(min, max);

    high_memory = __va((max << PAGE_SHIFT) - 1) + 1;
    max_pfn = max_low_pfn = max;
}

static inline int free_area(unsigned long pfn, unsigned long end, char *s)
{
    unsigned int pages = 0, size = (end - pfn) << (PAGE_SHIFT - 10);

    for (; pfn < end; pfn++) {
        struct page *page = pfn_to_page(pfn);
        ClearPageReserved(page);
        init_page_count(page);
        __free_page(page);
        pages++;
    }

    if (size && s)
        pr_info("Freeing %s memory: %dK\n", s, size);

    return pages;
}

/*
 * Poison init memory with an undefined instruction (0x0).
 */
static inline void poison_init_mem(void *s, size_t count)
{
    memset(s, 0, count);
}

#ifndef CONFIG_SPARSEMEM_VMEMMAP
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 - 1) + 1;

    /*
     * Convert to physical addresses, and round start upwards and end
     * downwards.
     */
    pg = (unsigned long)PAGE_ALIGN(__pa(start_pg));
    pgend = (unsigned long)__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(void)
{
    unsigned long start, prev_end = 0;
    struct memblock_region *reg;

    for_each_memblock(memory, reg) {
        start = __phys_to_pfn(reg->base);

#ifdef CONFIG_SPARSEMEM
        /*
         * Take care not to free memmap entries that don't exist due
         * to SPARSEMEM sections which aren't present.
         */
        start = min(start, ALIGN(prev_end, PAGES_PER_SECTION));
#endif
        /*
         * If we had a previous bank, and there is a space between the
         * current bank and the previous, free it.
         */
        if (prev_end && prev_end < start)
            free_memmap(prev_end, 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_end = ALIGN(start + __phys_to_pfn(reg->size),
                 MAX_ORDER_NR_PAGES);
    }

#ifdef CONFIG_SPARSEMEM
    if (!IS_ALIGNED(prev_end, PAGES_PER_SECTION))
        free_memmap(prev_end, ALIGN(prev_end, PAGES_PER_SECTION));
#endif
}
#endif  /* !CONFIG_SPARSEMEM_VMEMMAP */

/*
 * 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)
{
    unsigned long reserved_pages, free_pages;
    struct memblock_region *reg;

    arm64_swiotlb_init();

    max_mapnr   = pfn_to_page(max_pfn + PHYS_PFN_OFFSET) - mem_map;

#ifndef CONFIG_SPARSEMEM_VMEMMAP
    /* this will put all unused low memory onto the freelists */
    free_unused_memmap();
#endif

    totalram_pages += free_all_bootmem();

    reserved_pages = free_pages = 0;

    for_each_memblock(memory, reg) {
        unsigned int pfn1, pfn2;
        struct page *page, *end;

        pfn1 = __phys_to_pfn(reg->base);
        pfn2 = pfn1 + __phys_to_pfn(reg->size);

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

        do {
            if (PageReserved(page))
                reserved_pages++;
            else if (!page_count(page))
                free_pages++;
            page++;
        } while (page < end);
    }

    /*
     * Since our memory may not be contiguous, calculate the real number
     * of pages we have in this system.
     */
    pr_info("Memory:");
    num_physpages = 0;
    for_each_memblock(memory, reg) {
        unsigned long pages = memblock_region_memory_end_pfn(reg) -
            memblock_region_memory_base_pfn(reg);
        num_physpages += pages;
        printk(" %ldMB", pages >> (20 - PAGE_SHIFT));
    }
    printk(" = %luMB total\n", num_physpages >> (20 - PAGE_SHIFT));

    pr_notice("Memory: %luk/%luk available, %luk reserved\n",
          nr_free_pages() << (PAGE_SHIFT-10),
          free_pages << (PAGE_SHIFT-10),
          reserved_pages << (PAGE_SHIFT-10));

#define MLK(b, t) b, t, ((t) - (b)) >> 10
#define MLM(b, t) b, t, ((t) - (b)) >> 20
#define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t) - (b)), SZ_1K)

    pr_notice("Virtual kernel memory layout:\n"
          "    vmalloc : 0x%16lx - 0x%16lx   (%6ld MB)\n"
#ifdef CONFIG_SPARSEMEM_VMEMMAP
          "    vmemmap : 0x%16lx - 0x%16lx   (%6ld MB)\n"
#endif
          "    modules : 0x%16lx - 0x%16lx   (%6ld MB)\n"
          "    memory  : 0x%16lx - 0x%16lx   (%6ld MB)\n"
          "      .init : 0x%p" " - 0x%p" "   (%6ld kB)\n"
          "      .text : 0x%p" " - 0x%p" "   (%6ld kB)\n"
          "      .data : 0x%p" " - 0x%p" "   (%6ld kB)\n",
          MLM(VMALLOC_START, VMALLOC_END),
#ifdef CONFIG_SPARSEMEM_VMEMMAP
          MLM((unsigned long)virt_to_page(PAGE_OFFSET),
              (unsigned long)virt_to_page(high_memory)),
#endif
          MLM(MODULES_VADDR, MODULES_END),
          MLM(PAGE_OFFSET, (unsigned long)high_memory),

          MLK_ROUNDUP(__init_begin, __init_end),
          MLK_ROUNDUP(_text, _etext),
          MLK_ROUNDUP(_sdata, _edata));

#undef MLK
#undef MLM
#undef MLK_ROUNDUP

    /*
     * Check boundaries twice: Some fundamental inconsistencies can be
     * detected at build time already.
     */
#ifdef CONFIG_COMPAT
    BUILD_BUG_ON(TASK_SIZE_32           > TASK_SIZE_64);
#endif
    BUILD_BUG_ON(TASK_SIZE_64           > MODULES_VADDR);
    BUG_ON(TASK_SIZE_64             > MODULES_VADDR);

    if (PAGE_SIZE >= 16384 && num_physpages <= 128) {
        extern int sysctl_overcommit_memory;
        /*
         * 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)
{
    poison_init_mem(__init_begin, __init_end - __init_begin);
    totalram_pages += free_area(__phys_to_pfn(__pa(__init_begin)),
                    __phys_to_pfn(__pa(__init_end)),
                    "init");
}

#ifdef CONFIG_BLK_DEV_INITRD

static int keep_initrd;

void free_initrd_mem(unsigned long start, unsigned long end)
{
    if (!keep_initrd) {
        poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
        totalram_pages += free_area(__phys_to_pfn(__pa(start)),
                        __phys_to_pfn(__pa(end)),
                        "initrd");
    }
}

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

__setup("keepinitrd", keepinitrd_setup);
#endif