init.c

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/*
 * Copyright (C) 2007-2008 Michal Simek <[email protected]>
 * Copyright (C) 2006 Atmark Techno, Inc.
 *
 * 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.
 */

#include <linux/bootmem.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/memblock.h>
#include <linux/mm.h> /* mem_init */
#include <linux/initrd.h>
#include <linux/pagemap.h>
#include <linux/pfn.h>
#include <linux/slab.h>
#include <linux/swap.h>
#include <linux/export.h>

#include <asm/page.h>
#include <asm/mmu_context.h>
#include <asm/pgalloc.h>
#include <asm/sections.h>
#include <asm/tlb.h>
#include <asm/fixmap.h>

/* Use for MMU and noMMU because of PCI generic code */
int mem_init_done;

#ifndef CONFIG_MMU
unsigned int __page_offset;
EXPORT_SYMBOL(__page_offset);

#else
static int init_bootmem_done;
#endif /* CONFIG_MMU */

char *klimit = _end;

/*
 * Initialize the bootmem system and give it all the memory we
 * have available.
 */
unsigned long memory_start;
EXPORT_SYMBOL(memory_start);
unsigned long memory_size;
EXPORT_SYMBOL(memory_size);
unsigned long lowmem_size;

#ifdef CONFIG_HIGHMEM
pte_t *kmap_pte;
EXPORT_SYMBOL(kmap_pte);
pgprot_t kmap_prot;
EXPORT_SYMBOL(kmap_prot);

static inline pte_t *virt_to_kpte(unsigned long vaddr)
{
    return pte_offset_kernel(pmd_offset(pgd_offset_k(vaddr),
            vaddr), vaddr);
}

static void __init highmem_init(void)
{
    pr_debug("%x\n", (u32)PKMAP_BASE);
    map_page(PKMAP_BASE, 0, 0); /* XXX gross */
    pkmap_page_table = virt_to_kpte(PKMAP_BASE);

    kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
    kmap_prot = PAGE_KERNEL;
}

static unsigned long highmem_setup(void)
{
    unsigned long pfn;
    unsigned long reservedpages = 0;

    for (pfn = max_low_pfn; pfn < max_pfn; ++pfn) {
        struct page *page = pfn_to_page(pfn);

        /* FIXME not sure about */
        if (memblock_is_reserved(pfn << PAGE_SHIFT))
            continue;
        ClearPageReserved(page);
        init_page_count(page);
        __free_page(page);
        totalhigh_pages++;
        reservedpages++;
    }
    totalram_pages += totalhigh_pages;
    printk(KERN_INFO "High memory: %luk\n",
                    totalhigh_pages << (PAGE_SHIFT-10));

    return reservedpages;
}
#endif /* CONFIG_HIGHMEM */

/*
 * paging_init() sets up the page tables - in fact we've already done this.
 */
static void __init paging_init(void)
{
    unsigned long zones_size[MAX_NR_ZONES];
#ifdef CONFIG_MMU
    int idx;

    /* Setup fixmaps */
    for (idx = 0; idx < __end_of_fixed_addresses; idx++)
        clear_fixmap(idx);
#endif

    /* Clean every zones */
    memset(zones_size, 0, sizeof(zones_size));

#ifdef CONFIG_HIGHMEM
    highmem_init();

    zones_size[ZONE_DMA] = max_low_pfn;
    zones_size[ZONE_HIGHMEM] = max_pfn;
#else
    zones_size[ZONE_DMA] = max_pfn;
#endif

    /* We don't have holes in memory map */
    free_area_init_nodes(zones_size);
}

void __init setup_memory(void)
{
    unsigned long map_size;
    struct memblock_region *reg;

#ifndef CONFIG_MMU
    u32 kernel_align_start, kernel_align_size;

    /* Find main memory where is the kernel */
    for_each_memblock(memory, reg) {
        memory_start = (u32)reg->base;
        lowmem_size = reg->size;
        if ((memory_start <= (u32)_text) &&
            ((u32)_text <= (memory_start + lowmem_size - 1))) {
            memory_size = lowmem_size;
            PAGE_OFFSET = memory_start;
            printk(KERN_INFO "%s: Main mem: 0x%x, "
                "size 0x%08x\n", __func__, (u32) memory_start,
                    (u32) memory_size);
            break;
        }
    }

    if (!memory_start || !memory_size) {
        panic("%s: Missing memory setting 0x%08x, size=0x%08x\n",
            __func__, (u32) memory_start, (u32) memory_size);
    }

    /* reservation of region where is the kernel */
    kernel_align_start = PAGE_DOWN((u32)_text);
    /* ALIGN can be remove because _end in vmlinux.lds.S is align */
    kernel_align_size = PAGE_UP((u32)klimit) - kernel_align_start;
    printk(KERN_INFO "%s: kernel addr:0x%08x-0x%08x size=0x%08x\n",
        __func__, kernel_align_start, kernel_align_start
            + kernel_align_size, kernel_align_size);
    memblock_reserve(kernel_align_start, kernel_align_size);
#endif
    /*
     * Kernel:
     * start: base phys address of kernel - page align
     * end: base phys address of kernel - page align
     *
     * min_low_pfn - the first page (mm/bootmem.c - node_boot_start)
     * max_low_pfn
     * max_mapnr - the first unused page (mm/bootmem.c - node_low_pfn)
     * num_physpages - number of all pages
     */

    /* memory start is from the kernel end (aligned) to higher addr */
    min_low_pfn = memory_start >> PAGE_SHIFT; /* minimum for allocation */
    /* RAM is assumed contiguous */
    num_physpages = max_mapnr = memory_size >> PAGE_SHIFT;
    max_low_pfn = ((u64)memory_start + (u64)lowmem_size) >> PAGE_SHIFT;
    max_pfn = ((u64)memory_start + (u64)memory_size) >> PAGE_SHIFT;

    printk(KERN_INFO "%s: max_mapnr: %#lx\n", __func__, max_mapnr);
    printk(KERN_INFO "%s: min_low_pfn: %#lx\n", __func__, min_low_pfn);
    printk(KERN_INFO "%s: max_low_pfn: %#lx\n", __func__, max_low_pfn);
    printk(KERN_INFO "%s: max_pfn: %#lx\n", __func__, max_pfn);

    /*
     * Find an area to use for the bootmem bitmap.
     * We look for the first area which is at least
     * 128kB in length (128kB is enough for a bitmap
     * for 4GB of memory, using 4kB pages), plus 1 page
     * (in case the address isn't page-aligned).
     */
    map_size = init_bootmem_node(NODE_DATA(0),
        PFN_UP(TOPHYS((u32)klimit)), min_low_pfn, max_low_pfn);
    memblock_reserve(PFN_UP(TOPHYS((u32)klimit)) << PAGE_SHIFT, map_size);

    /* Add active regions with valid PFNs */
    for_each_memblock(memory, reg) {
        unsigned long start_pfn, end_pfn;

        start_pfn = memblock_region_memory_base_pfn(reg);
        end_pfn = memblock_region_memory_end_pfn(reg);
        memblock_set_node(start_pfn << PAGE_SHIFT,
                    (end_pfn - start_pfn) << PAGE_SHIFT, 0);
    }

    /* free bootmem is whole main memory */
    free_bootmem_with_active_regions(0, max_low_pfn);

    /* reserve allocate blocks */
    for_each_memblock(reserved, reg) {
        unsigned long top = reg->base + reg->size - 1;

        pr_debug("reserved - 0x%08x-0x%08x, %lx, %lx\n",
             (u32) reg->base, (u32) reg->size, top,
                        memory_start + lowmem_size - 1);

        if (top <= (memory_start + lowmem_size - 1)) {
            reserve_bootmem(reg->base, reg->size, BOOTMEM_DEFAULT);
        } else if (reg->base < (memory_start + lowmem_size - 1)) {
            unsigned long trunc_size = memory_start + lowmem_size -
                                reg->base;
            reserve_bootmem(reg->base, trunc_size, BOOTMEM_DEFAULT);
        }
    }

    /* XXX need to clip this if using highmem? */
    sparse_memory_present_with_active_regions(0);

#ifdef CONFIG_MMU
    init_bootmem_done = 1;
#endif
    paging_init();
}

void free_init_pages(char *what, unsigned long begin, unsigned long end)
{
    unsigned long addr;

    for (addr = begin; addr < end; addr += PAGE_SIZE) {
        ClearPageReserved(virt_to_page(addr));
        init_page_count(virt_to_page(addr));
        free_page(addr);
        totalram_pages++;
    }
    printk(KERN_INFO "Freeing %s: %ldk freed\n", what, (end - begin) >> 10);
}

#ifdef CONFIG_BLK_DEV_INITRD
void free_initrd_mem(unsigned long start, unsigned long end)
{
    int pages = 0;
    for (; start < end; start += PAGE_SIZE) {
        ClearPageReserved(virt_to_page(start));
        init_page_count(virt_to_page(start));
        free_page(start);
        totalram_pages++;
        pages++;
    }
    printk(KERN_NOTICE "Freeing initrd memory: %dk freed\n",
                    (int)(pages * (PAGE_SIZE / 1024)));
}
#endif

void free_initmem(void)
{
    free_init_pages("unused kernel memory",
            (unsigned long)(&__init_begin),
            (unsigned long)(&__init_end));
}

void __init mem_init(void)
{
    pg_data_t *pgdat;
    unsigned long reservedpages = 0, codesize, initsize, datasize, bsssize;

    high_memory = (void *)__va(memory_start + lowmem_size - 1);

    /* this will put all memory onto the freelists */
    totalram_pages += free_all_bootmem();

    for_each_online_pgdat(pgdat) {
        unsigned long i;
        struct page *page;

        for (i = 0; i < pgdat->node_spanned_pages; i++) {
            if (!pfn_valid(pgdat->node_start_pfn + i))
                continue;
            page = pgdat_page_nr(pgdat, i);
            if (PageReserved(page))
                reservedpages++;
        }
    }

#ifdef CONFIG_HIGHMEM
    reservedpages -= highmem_setup();
#endif

    codesize = (unsigned long)&_sdata - (unsigned long)&_stext;
    datasize = (unsigned long)&_edata - (unsigned long)&_sdata;
    initsize = (unsigned long)&__init_end - (unsigned long)&__init_begin;
    bsssize = (unsigned long)&__bss_stop - (unsigned long)&__bss_start;

    pr_info("Memory: %luk/%luk available (%luk kernel code, "
        "%luk reserved, %luk data, %luk bss, %luk init)\n",
        nr_free_pages() << (PAGE_SHIFT-10),
        num_physpages << (PAGE_SHIFT-10),
        codesize >> 10,
        reservedpages << (PAGE_SHIFT-10),
        datasize >> 10,
        bsssize >> 10,
        initsize >> 10);

#ifdef CONFIG_MMU
    pr_info("Kernel virtual memory layout:\n");
    pr_info("  * 0x%08lx..0x%08lx  : fixmap\n", FIXADDR_START, FIXADDR_TOP);
#ifdef CONFIG_HIGHMEM
    pr_info("  * 0x%08lx..0x%08lx  : highmem PTEs\n",
        PKMAP_BASE, PKMAP_ADDR(LAST_PKMAP));
#endif /* CONFIG_HIGHMEM */
    pr_info("  * 0x%08lx..0x%08lx  : early ioremap\n",
        ioremap_bot, ioremap_base);
    pr_info("  * 0x%08lx..0x%08lx  : vmalloc & ioremap\n",
        (unsigned long)VMALLOC_START, VMALLOC_END);
#endif
    mem_init_done = 1;
}

#ifndef CONFIG_MMU
int page_is_ram(unsigned long pfn)
{
    return __range_ok(pfn, 0);
}
#else
int page_is_ram(unsigned long pfn)
{
    return pfn < max_low_pfn;
}

/*
 * Check for command-line options that affect what MMU_init will do.
 */
static void mm_cmdline_setup(void)
{
    unsigned long maxmem = 0;
    char *p = cmd_line;

    /* Look for mem= option on command line */
    p = strstr(cmd_line, "mem=");
    if (p) {
        p += 4;
        maxmem = memparse(p, &p);
        if (maxmem && memory_size > maxmem) {
            memory_size = maxmem;
            memblock.memory.regions[0].size = memory_size;
        }
    }
}

/*
 * MMU_init_hw does the chip-specific initialization of the MMU hardware.
 */
static void __init mmu_init_hw(void)
{
    /*
     * The Zone Protection Register (ZPR) defines how protection will
     * be applied to every page which is a member of a given zone. At
     * present, we utilize only two of the zones.
     * The zone index bits (of ZSEL) in the PTE are used for software
     * indicators, except the LSB.  For user access, zone 1 is used,
     * for kernel access, zone 0 is used.  We set all but zone 1
     * to zero, allowing only kernel access as indicated in the PTE.
     * For zone 1, we set a 01 binary (a value of 10 will not work)
     * to allow user access as indicated in the PTE.  This also allows
     * kernel access as indicated in the PTE.
     */
    __asm__ __volatile__ ("ori r11, r0, 0x10000000;" \
            "mts rzpr, r11;"
            : : : "r11");
}

/*
 * MMU_init sets up the basic memory mappings for the kernel,
 * including both RAM and possibly some I/O regions,
 * and sets up the page tables and the MMU hardware ready to go.
 */

/* called from head.S */
asmlinkage void __init mmu_init(void)
{
    unsigned int kstart, ksize;

    if (!memblock.reserved.cnt) {
        printk(KERN_EMERG "Error memory count\n");
        machine_restart(NULL);
    }

    if ((u32) memblock.memory.regions[0].size < 0x400000) {
        printk(KERN_EMERG "Memory must be greater than 4MB\n");
        machine_restart(NULL);
    }

    if ((u32) memblock.memory.regions[0].size < kernel_tlb) {
        printk(KERN_EMERG "Kernel size is greater than memory node\n");
        machine_restart(NULL);
    }

    /* Find main memory where the kernel is */
    memory_start = (u32) memblock.memory.regions[0].base;
    lowmem_size = memory_size = (u32) memblock.memory.regions[0].size;

    if (lowmem_size > CONFIG_LOWMEM_SIZE) {
        lowmem_size = CONFIG_LOWMEM_SIZE;
#ifndef CONFIG_HIGHMEM
        memory_size = lowmem_size;
#endif
    }

    mm_cmdline_setup(); /* FIXME parse args from command line - not used */

    /*
     * Map out the kernel text/data/bss from the available physical
     * memory.
     */
    kstart = __pa(CONFIG_KERNEL_START); /* kernel start */
    /* kernel size */
    ksize = PAGE_ALIGN(((u32)_end - (u32)CONFIG_KERNEL_START));
    memblock_reserve(kstart, ksize);

#if defined(CONFIG_BLK_DEV_INITRD)
    /* Remove the init RAM disk from the available memory. */
/*  if (initrd_start) {
        mem_pieces_remove(&phys_avail, __pa(initrd_start),
                  initrd_end - initrd_start, 1);
    }*/
#endif /* CONFIG_BLK_DEV_INITRD */

    /* Initialize the MMU hardware */
    mmu_init_hw();

    /* Map in all of RAM starting at CONFIG_KERNEL_START */
    mapin_ram();

    /* Extend vmalloc and ioremap area as big as possible */
#ifdef CONFIG_HIGHMEM
    ioremap_base = ioremap_bot = PKMAP_BASE;
#else
    ioremap_base = ioremap_bot = FIXADDR_START;
#endif

    /* Initialize the context management stuff */
    mmu_context_init();

    /* Shortly after that, the entire linear mapping will be available */
    /* This will also cause that unflatten device tree will be allocated
     * inside 768MB limit */
    memblock_set_current_limit(memory_start + lowmem_size - 1);
}

/* This is only called until mem_init is done. */
void __init *early_get_page(void)
{
    void *p;
    if (init_bootmem_done) {
        p = alloc_bootmem_pages(PAGE_SIZE);
    } else {
        /*
         * Mem start + kernel_tlb -> here is limit
         * because of mem mapping from head.S
         */
        p = __va(memblock_alloc_base(PAGE_SIZE, PAGE_SIZE,
                    memory_start + kernel_tlb));
    }
    return p;
}

#endif /* CONFIG_MMU */

void * __init_refok alloc_maybe_bootmem(size_t size, gfp_t mask)
{
    if (mem_init_done)
        return kmalloc(size, mask);
    else
        return alloc_bootmem(size);
}

void * __init_refok zalloc_maybe_bootmem(size_t size, gfp_t mask)
{
    void *p;

    if (mem_init_done)
        p = kzalloc(size, mask);
    else {
        p = alloc_bootmem(size);
        if (p)
            memset(p, 0, size);
    }
    return p;
}