init.c

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/*
 * arch/xtensa/mm/init.c
 *
 * Derived from MIPS, PPC.
 *
 * 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.
 *
 * Copyright (C) 2001 - 2005 Tensilica Inc.
 *
 * Chris Zankel <[email protected]>
 * Joe Taylor   <[email protected], [email protected]>
 * Marc Gauthier
 * Kevin Chea
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/bootmem.h>
#include <linux/gfp.h>
#include <linux/swap.h>
#include <linux/mman.h>
#include <linux/nodemask.h>
#include <linux/mm.h>

#include <asm/bootparam.h>
#include <asm/page.h>
#include <asm/sections.h>

/*
 * mem_reserve(start, end, must_exist)
 *
 * Reserve some memory from the memory pool.
 *
 * Parameters:
 *  start   Start of region,
 *  end     End of region,
 *  must_exist  Must exist in memory pool.
 *
 * Returns:
 *  0 (memory area couldn't be mapped)
 * -1 (success)
 */

int __init mem_reserve(unsigned long start, unsigned long end, int must_exist)
{
    int i;

    if (start == end)
        return 0;

    start = start & PAGE_MASK;
    end = PAGE_ALIGN(end);

    for (i = 0; i < sysmem.nr_banks; i++)
        if (start < sysmem.bank[i].end
            && end >= sysmem.bank[i].start)
            break;

    if (i == sysmem.nr_banks) {
        if (must_exist)
            printk (KERN_WARNING "mem_reserve: [0x%0lx, 0x%0lx) "
                "not in any region!\n", start, end);
        return 0;
    }

    if (start > sysmem.bank[i].start) {
        if (end < sysmem.bank[i].end) {
            /* split entry */
            if (sysmem.nr_banks >= SYSMEM_BANKS_MAX)
                panic("meminfo overflow\n");
            sysmem.bank[sysmem.nr_banks].start = end;
            sysmem.bank[sysmem.nr_banks].end = sysmem.bank[i].end;
            sysmem.nr_banks++;
        }
        sysmem.bank[i].end = start;
    } else {
        if (end < sysmem.bank[i].end)
            sysmem.bank[i].start = end;
        else {
            /* remove entry */
            sysmem.nr_banks--;
            sysmem.bank[i].start = sysmem.bank[sysmem.nr_banks].start;
            sysmem.bank[i].end   = sysmem.bank[sysmem.nr_banks].end;
        }
    }
    return -1;
}


/*
 * Initialize the bootmem system and give it all the memory we have available.
 */

void __init bootmem_init(void)
{
    unsigned long pfn;
    unsigned long bootmap_start, bootmap_size;
    int i;

    max_low_pfn = max_pfn = 0;
    min_low_pfn = ~0;

    for (i=0; i < sysmem.nr_banks; i++) {
        pfn = PAGE_ALIGN(sysmem.bank[i].start) >> PAGE_SHIFT;
        if (pfn < min_low_pfn)
            min_low_pfn = pfn;
        pfn = PAGE_ALIGN(sysmem.bank[i].end - 1) >> PAGE_SHIFT;
        if (pfn > max_pfn)
            max_pfn = pfn;
    }

    if (min_low_pfn > max_pfn)
        panic("No memory found!\n");

    max_low_pfn = max_pfn < MAX_MEM_PFN >> PAGE_SHIFT ?
        max_pfn : MAX_MEM_PFN >> PAGE_SHIFT;

    /* Find an area to use for the bootmem bitmap. */

    bootmap_size = bootmem_bootmap_pages(max_low_pfn - min_low_pfn);
    bootmap_size <<= PAGE_SHIFT;
    bootmap_start = ~0;

    for (i=0; i<sysmem.nr_banks; i++)
        if (sysmem.bank[i].end - sysmem.bank[i].start >= bootmap_size) {
            bootmap_start = sysmem.bank[i].start;
            break;
        }

    if (bootmap_start == ~0UL)
        panic("Cannot find %ld bytes for bootmap\n", bootmap_size);

    /* Reserve the bootmem bitmap area */

    mem_reserve(bootmap_start, bootmap_start + bootmap_size, 1);
    bootmap_size = init_bootmem_node(NODE_DATA(0),
                     bootmap_start >> PAGE_SHIFT,
                     min_low_pfn,
                     max_low_pfn);

    /* Add all remaining memory pieces into the bootmem map */

    for (i=0; i<sysmem.nr_banks; i++)
        free_bootmem(sysmem.bank[i].start,
                 sysmem.bank[i].end - sysmem.bank[i].start);

}


void __init zones_init(void)
{
    unsigned long zones_size[MAX_NR_ZONES];
    int i;

    /* All pages are DMA-able, so we put them all in the DMA zone. */

    zones_size[ZONE_DMA] = max_low_pfn - ARCH_PFN_OFFSET;
    for (i = 1; i < MAX_NR_ZONES; i++)
        zones_size[i] = 0;

#ifdef CONFIG_HIGHMEM
    zones_size[ZONE_HIGHMEM] = max_pfn - max_low_pfn;
#endif

    free_area_init_node(0, zones_size, ARCH_PFN_OFFSET, NULL);
}

/*
 * Initialize memory pages.
 */

void __init mem_init(void)
{
    unsigned long codesize, reservedpages, datasize, initsize;
    unsigned long highmemsize, tmp, ram;

    max_mapnr = num_physpages = max_low_pfn - ARCH_PFN_OFFSET;
    high_memory = (void *) __va(max_low_pfn << PAGE_SHIFT);
    highmemsize = 0;

#ifdef CONFIG_HIGHMEM
#error HIGHGMEM not implemented in init.c
#endif

    totalram_pages += free_all_bootmem();

    reservedpages = ram = 0;
    for (tmp = 0; tmp < max_mapnr; tmp++) {
        ram++;
        if (PageReserved(mem_map+tmp))
            reservedpages++;
    }

    codesize =  (unsigned long) _etext - (unsigned long) _stext;
    datasize =  (unsigned long) _edata - (unsigned long) _sdata;
    initsize =  (unsigned long) __init_end - (unsigned long) __init_begin;

    printk("Memory: %luk/%luk available (%ldk kernel code, %ldk reserved, "
           "%ldk data, %ldk init %ldk highmem)\n",
           nr_free_pages() << (PAGE_SHIFT-10),
           ram << (PAGE_SHIFT-10),
           codesize >> 10,
           reservedpages << (PAGE_SHIFT-10),
           datasize >> 10,
           initsize >> 10,
           highmemsize >> 10);
}

void
free_reserved_mem(void *start, void *end)
{
    for (; start < end; start += PAGE_SIZE) {
        ClearPageReserved(virt_to_page(start));
        init_page_count(virt_to_page(start));
        free_page((unsigned long)start);
        totalram_pages++;
    }
}

#ifdef CONFIG_BLK_DEV_INITRD
extern int initrd_is_mapped;

void free_initrd_mem(unsigned long start, unsigned long end)
{
    if (initrd_is_mapped) {
        free_reserved_mem((void*)start, (void*)end);
        printk ("Freeing initrd memory: %ldk freed\n",(end-start)>>10);
    }
}
#endif

void free_initmem(void)
{
    free_reserved_mem(__init_begin, __init_end);
    printk("Freeing unused kernel memory: %zuk freed\n",
           (__init_end - __init_begin) >> 10);
}