[PATCH] ARM: Add top_pmd, which points at the top-most page table

[linux-2.6/btrfs-unstable.git] / arch / arm / mm / mm-armv.c

/*
 *  linux/arch/arm/mm/mm-armv.c
 *
 *  Copyright (C) 1998-2002 Russell King
 *
 * 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.
 *
 *  Page table sludge for ARM v3 and v4 processor architectures.
 */
#include <linux/config.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/highmem.h>
#include <linux/nodemask.h>

#include <asm/pgalloc.h>
#include <asm/page.h>
#include <asm/io.h>
#include <asm/setup.h>
#include <asm/tlbflush.h>

#include <asm/mach/map.h>

#define CPOLICY_UNCACHED        0
#define CPOLICY_BUFFERED        1
#define CPOLICY_WRITETHROUGH    2
#define CPOLICY_WRITEBACK       3
#define CPOLICY_WRITEALLOC      4

static unsigned int cachepolicy __initdata = CPOLICY_WRITEBACK;
static unsigned int ecc_mask __initdata = 0;
pgprot_t pgprot_kernel;

EXPORT_SYMBOL(pgprot_kernel);

pmd_t *top_pmd;

struct cachepolicy {
        const char      policy[16];
        unsigned int    cr_mask;
        unsigned int    pmd;
        unsigned int    pte;
};

static struct cachepolicy cache_policies[] __initdata = {
        {
                .policy         = "uncached",
                .cr_mask        = CR_W|CR_C,
                .pmd            = PMD_SECT_UNCACHED,
                .pte            = 0,
        }, {
                .policy         = "buffered",
                .cr_mask        = CR_C,
                .pmd            = PMD_SECT_BUFFERED,
                .pte            = PTE_BUFFERABLE,
        }, {
                .policy         = "writethrough",
                .cr_mask        = 0,
                .pmd            = PMD_SECT_WT,
                .pte            = PTE_CACHEABLE,
        }, {
                .policy         = "writeback",
                .cr_mask        = 0,
                .pmd            = PMD_SECT_WB,
                .pte            = PTE_BUFFERABLE|PTE_CACHEABLE,
        }, {
                .policy         = "writealloc",
                .cr_mask        = 0,
                .pmd            = PMD_SECT_WBWA,
                .pte            = PTE_BUFFERABLE|PTE_CACHEABLE,
        }
};

/*
 * These are useful for identifing cache coherency
 * problems by allowing the cache or the cache and
 * writebuffer to be turned off.  (Note: the write
 * buffer should not be on and the cache off).
 */
static void __init early_cachepolicy(char **p)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(cache_policies); i++) {
                int len = strlen(cache_policies[i].policy);

                if (memcmp(*p, cache_policies[i].policy, len) == 0) {
                        cachepolicy = i;
                        cr_alignment &= ~cache_policies[i].cr_mask;
                        cr_no_alignment &= ~cache_policies[i].cr_mask;
                        *p += len;
                        break;
                }
        }
        if (i == ARRAY_SIZE(cache_policies))
                printk(KERN_ERR "ERROR: unknown or unsupported cache policy\n");
        flush_cache_all();
        set_cr(cr_alignment);
}

static void __init early_nocache(char **__unused)
{
        char *p = "buffered";
        printk(KERN_WARNING "nocache is deprecated; use cachepolicy=%s\n", p);
        early_cachepolicy(&p);
}

static void __init early_nowrite(char **__unused)
{
        char *p = "uncached";
        printk(KERN_WARNING "nowb is deprecated; use cachepolicy=%s\n", p);
        early_cachepolicy(&p);
}

static void __init early_ecc(char **p)
{
        if (memcmp(*p, "on", 2) == 0) {
                ecc_mask = PMD_PROTECTION;
                *p += 2;
        } else if (memcmp(*p, "off", 3) == 0) {
                ecc_mask = 0;
                *p += 3;
        }
}

__early_param("nocache", early_nocache);
__early_param("nowb", early_nowrite);
__early_param("cachepolicy=", early_cachepolicy);
__early_param("ecc=", early_ecc);

static int __init noalign_setup(char *__unused)
{
        cr_alignment &= ~CR_A;
        cr_no_alignment &= ~CR_A;
        set_cr(cr_alignment);
        return 1;
}

__setup("noalign", noalign_setup);

#define FIRST_KERNEL_PGD_NR     (FIRST_USER_PGD_NR + USER_PTRS_PER_PGD)

static inline pmd_t *pmd_off(pgd_t *pgd, unsigned long virt)
{
        return pmd_offset(pgd, virt);
}

static inline pmd_t *pmd_off_k(unsigned long virt)
{
        return pmd_off(pgd_offset_k(virt), virt);
}

/*
 * need to get a 16k page for level 1
 */
pgd_t *get_pgd_slow(struct mm_struct *mm)
{
        pgd_t *new_pgd, *init_pgd;
        pmd_t *new_pmd, *init_pmd;
        pte_t *new_pte, *init_pte;

        new_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, 2);
        if (!new_pgd)
                goto no_pgd;

        memzero(new_pgd, FIRST_KERNEL_PGD_NR * sizeof(pgd_t));

        init_pgd = pgd_offset_k(0);

        if (!vectors_high()) {
                /*
                 * This lock is here just to satisfy pmd_alloc and pte_lock
                 */
                spin_lock(&mm->page_table_lock);

                /*
                 * On ARM, first page must always be allocated since it
                 * contains the machine vectors.
                 */
                new_pmd = pmd_alloc(mm, new_pgd, 0);
                if (!new_pmd)
                        goto no_pmd;

                new_pte = pte_alloc_map(mm, new_pmd, 0);
                if (!new_pte)
                        goto no_pte;

                init_pmd = pmd_offset(init_pgd, 0);
                init_pte = pte_offset_map_nested(init_pmd, 0);
                set_pte(new_pte, *init_pte);
                pte_unmap_nested(init_pte);
                pte_unmap(new_pte);

                spin_unlock(&mm->page_table_lock);
        }

        /*
         * Copy over the kernel and IO PGD entries
         */
        memcpy(new_pgd + FIRST_KERNEL_PGD_NR, init_pgd + FIRST_KERNEL_PGD_NR,
                       (PTRS_PER_PGD - FIRST_KERNEL_PGD_NR) * sizeof(pgd_t));

        clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));

        return new_pgd;

no_pte:
        spin_unlock(&mm->page_table_lock);
        pmd_free(new_pmd);
        free_pages((unsigned long)new_pgd, 2);
        return NULL;

no_pmd:
        spin_unlock(&mm->page_table_lock);
        free_pages((unsigned long)new_pgd, 2);
        return NULL;

no_pgd:
        return NULL;
}

void free_pgd_slow(pgd_t *pgd)
{
        pmd_t *pmd;
        struct page *pte;

        if (!pgd)
                return;

        /* pgd is always present and good */
        pmd = pmd_off(pgd, 0);
        if (pmd_none(*pmd))
                goto free;
        if (pmd_bad(*pmd)) {
                pmd_ERROR(*pmd);
                pmd_clear(pmd);
                goto free;
        }

        pte = pmd_page(*pmd);
        pmd_clear(pmd);
        dec_page_state(nr_page_table_pages);
        pte_free(pte);
        pmd_free(pmd);
free:
        free_pages((unsigned long) pgd, 2);
}

/*
 * Create a SECTION PGD between VIRT and PHYS in domain
 * DOMAIN with protection PROT.  This operates on half-
 * pgdir entry increments.
 */
static inline void
alloc_init_section(unsigned long virt, unsigned long phys, int prot)
{
        pmd_t *pmdp = pmd_off_k(virt);

        if (virt & (1 << 20))
                pmdp++;

        *pmdp = __pmd(phys | prot);
        flush_pmd_entry(pmdp);
}

/*
 * Create a SUPER SECTION PGD between VIRT and PHYS with protection PROT
 */
static inline void
alloc_init_supersection(unsigned long virt, unsigned long phys, int prot)
{
        int i;

        for (i = 0; i < 16; i += 1) {
                alloc_init_section(virt, phys & SUPERSECTION_MASK,
                                   prot | PMD_SECT_SUPER);

                virt += (PGDIR_SIZE / 2);
                phys += (PGDIR_SIZE / 2);
        }
}

/*
 * Add a PAGE mapping between VIRT and PHYS in domain
 * DOMAIN with protection PROT.  Note that due to the
 * way we map the PTEs, we must allocate two PTE_SIZE'd
 * blocks - one for the Linux pte table, and one for
 * the hardware pte table.
 */
static inline void
alloc_init_page(unsigned long virt, unsigned long phys, unsigned int prot_l1, pgprot_t prot)
{
        pmd_t *pmdp = pmd_off_k(virt);
        pte_t *ptep;

        if (pmd_none(*pmdp)) {
                unsigned long pmdval;
                ptep = alloc_bootmem_low_pages(2 * PTRS_PER_PTE *
                                               sizeof(pte_t));

                pmdval = __pa(ptep) | prot_l1;
                pmdp[0] = __pmd(pmdval);
                pmdp[1] = __pmd(pmdval + 256 * sizeof(pte_t));
                flush_pmd_entry(pmdp);
        }
        ptep = pte_offset_kernel(pmdp, virt);

        set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, prot));
}

/*
 * Clear any PGD mapping.  On a two-level page table system,
 * the clearance is done by the middle-level functions (pmd)
 * rather than the top-level (pgd) functions.
 */
static inline void clear_mapping(unsigned long virt)
{
        pmd_clear(pmd_off_k(virt));
}

struct mem_types {
        unsigned int    prot_pte;
        unsigned int    prot_l1;
        unsigned int    prot_sect;
        unsigned int    domain;
};

static struct mem_types mem_types[] __initdata = {
        [MT_DEVICE] = {
                .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
                                L_PTE_WRITE,
                .prot_l1   = PMD_TYPE_TABLE,
                .prot_sect = PMD_TYPE_SECT | PMD_SECT_UNCACHED |
                                PMD_SECT_AP_WRITE,
                .domain    = DOMAIN_IO,
        },
        [MT_CACHECLEAN] = {
                .prot_sect = PMD_TYPE_SECT,
                .domain    = DOMAIN_KERNEL,
        },
        [MT_MINICLEAN] = {
                .prot_sect = PMD_TYPE_SECT | PMD_SECT_MINICACHE,
                .domain    = DOMAIN_KERNEL,
        },
        [MT_LOW_VECTORS] = {
                .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
                                L_PTE_EXEC,
                .prot_l1   = PMD_TYPE_TABLE,
                .domain    = DOMAIN_USER,
        },
        [MT_HIGH_VECTORS] = {
                .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
                                L_PTE_USER | L_PTE_EXEC,
                .prot_l1   = PMD_TYPE_TABLE,
                .domain    = DOMAIN_USER,
        },
        [MT_MEMORY] = {
                .prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE,
                .domain    = DOMAIN_KERNEL,
        },
        [MT_ROM] = {
                .prot_sect = PMD_TYPE_SECT,
                .domain    = DOMAIN_KERNEL,
        },
        [MT_IXP2000_DEVICE] = { /* IXP2400 requires XCB=101 for on-chip I/O */
                .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
                                L_PTE_WRITE,
                .prot_l1   = PMD_TYPE_TABLE,
                .prot_sect = PMD_TYPE_SECT | PMD_SECT_UNCACHED |
                                PMD_SECT_AP_WRITE | PMD_SECT_BUFFERABLE |
                                PMD_SECT_TEX(1),
                .domain    = DOMAIN_IO,
        }
};

/*
 * Adjust the PMD section entries according to the CPU in use.
 */
static void __init build_mem_type_table(void)
{
        struct cachepolicy *cp;
        unsigned int cr = get_cr();
        int cpu_arch = cpu_architecture();
        int i;

#if defined(CONFIG_CPU_DCACHE_DISABLE)
        if (cachepolicy > CPOLICY_BUFFERED)
                cachepolicy = CPOLICY_BUFFERED;
#elif defined(CONFIG_CPU_DCACHE_WRITETHROUGH)
        if (cachepolicy > CPOLICY_WRITETHROUGH)
                cachepolicy = CPOLICY_WRITETHROUGH;
#endif
        if (cpu_arch < CPU_ARCH_ARMv5) {
                if (cachepolicy >= CPOLICY_WRITEALLOC)
                        cachepolicy = CPOLICY_WRITEBACK;
                ecc_mask = 0;
        }

        if (cpu_arch <= CPU_ARCH_ARMv5) {
                for (i = 0; i < ARRAY_SIZE(mem_types); i++) {
                        if (mem_types[i].prot_l1)
                                mem_types[i].prot_l1 |= PMD_BIT4;
                        if (mem_types[i].prot_sect)
                                mem_types[i].prot_sect |= PMD_BIT4;
                }
        }

        /*
         * ARMv6 and above have extended page tables.
         */
        if (cpu_arch >= CPU_ARCH_ARMv6 && (cr & CR_XP)) {
                /*
                 * bit 4 becomes XN which we must clear for the
                 * kernel memory mapping.
                 */
                mem_types[MT_MEMORY].prot_sect &= ~PMD_BIT4;
                mem_types[MT_ROM].prot_sect &= ~PMD_BIT4;
                /*
                 * Mark cache clean areas and XIP ROM read only
                 * from SVC mode and no access from userspace.
                 */
                mem_types[MT_ROM].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
                mem_types[MT_MINICLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
                mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
        }

        cp = &cache_policies[cachepolicy];

        if (cpu_arch >= CPU_ARCH_ARMv5) {
                mem_types[MT_LOW_VECTORS].prot_pte |= cp->pte & PTE_CACHEABLE;
                mem_types[MT_HIGH_VECTORS].prot_pte |= cp->pte & PTE_CACHEABLE;
        } else {
                mem_types[MT_LOW_VECTORS].prot_pte |= cp->pte;
                mem_types[MT_HIGH_VECTORS].prot_pte |= cp->pte;
                mem_types[MT_MINICLEAN].prot_sect &= ~PMD_SECT_TEX(1);
        }

        mem_types[MT_LOW_VECTORS].prot_l1 |= ecc_mask;
        mem_types[MT_HIGH_VECTORS].prot_l1 |= ecc_mask;
        mem_types[MT_MEMORY].prot_sect |= ecc_mask | cp->pmd;
        mem_types[MT_ROM].prot_sect |= cp->pmd;

        for (i = 0; i < 16; i++) {
                unsigned long v = pgprot_val(protection_map[i]);
                v &= (~(PTE_BUFFERABLE|PTE_CACHEABLE)) | cp->pte;
                protection_map[i] = __pgprot(v);
        }

        pgprot_kernel = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG |
                                 L_PTE_DIRTY | L_PTE_WRITE |
                                 L_PTE_EXEC | cp->pte);

        switch (cp->pmd) {
        case PMD_SECT_WT:
                mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_WT;
                break;
        case PMD_SECT_WB:
        case PMD_SECT_WBWA:
                mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_WB;
                break;
        }
        printk("Memory policy: ECC %sabled, Data cache %s\n",
                ecc_mask ? "en" : "dis", cp->policy);
}

#define vectors_base()  (vectors_high() ? 0xffff0000 : 0)

/*
 * Create the page directory entries and any necessary
 * page tables for the mapping specified by `md'.  We
 * are able to cope here with varying sizes and address
 * offsets, and we take full advantage of sections and
 * supersections.
 */
static void __init create_mapping(struct map_desc *md)
{
        unsigned long virt, length;
        int prot_sect, prot_l1, domain;
        pgprot_t prot_pte;
        long off;

        if (md->virtual != vectors_base() && md->virtual < TASK_SIZE) {
                printk(KERN_WARNING "BUG: not creating mapping for "
                       "0x%08lx at 0x%08lx in user region\n",
                       md->physical, md->virtual);
                return;
        }

        if ((md->type == MT_DEVICE || md->type == MT_ROM) &&
            md->virtual >= PAGE_OFFSET && md->virtual < VMALLOC_END) {
                printk(KERN_WARNING "BUG: mapping for 0x%08lx at 0x%08lx "
                       "overlaps vmalloc space\n",
                       md->physical, md->virtual);
        }

        domain    = mem_types[md->type].domain;
        prot_pte  = __pgprot(mem_types[md->type].prot_pte);
        prot_l1   = mem_types[md->type].prot_l1 | PMD_DOMAIN(domain);
        prot_sect = mem_types[md->type].prot_sect | PMD_DOMAIN(domain);

        virt   = md->virtual;
        off    = md->physical - virt;
        length = md->length;

        if (mem_types[md->type].prot_l1 == 0 &&
            (virt & 0xfffff || (virt + off) & 0xfffff || (virt + length) & 0xfffff)) {
                printk(KERN_WARNING "BUG: map for 0x%08lx at 0x%08lx can not "
                       "be mapped using pages, ignoring.\n",
                       md->physical, md->virtual);
                return;
        }

        while ((virt & 0xfffff || (virt + off) & 0xfffff) && length >= PAGE_SIZE) {
                alloc_init_page(virt, virt + off, prot_l1, prot_pte);

                virt   += PAGE_SIZE;
                length -= PAGE_SIZE;
        }

        /* N.B. ARMv6 supersections are only defined to work with domain 0.
         *      Since domain assignments can in fact be arbitrary, the
         *      'domain == 0' check below is required to insure that ARMv6
         *      supersections are only allocated for domain 0 regardless
         *      of the actual domain assignments in use.
         */
        if (cpu_architecture() >= CPU_ARCH_ARMv6 && domain == 0) {
                /* Align to supersection boundary */
                while ((virt & ~SUPERSECTION_MASK || (virt + off) &
                        ~SUPERSECTION_MASK) && length >= (PGDIR_SIZE / 2)) {
                        alloc_init_section(virt, virt + off, prot_sect);

                        virt   += (PGDIR_SIZE / 2);
                        length -= (PGDIR_SIZE / 2);
                }

                while (length >= SUPERSECTION_SIZE) {
                        alloc_init_supersection(virt, virt + off, prot_sect);

                        virt   += SUPERSECTION_SIZE;
                        length -= SUPERSECTION_SIZE;
                }
        }

        /*
         * A section mapping covers half a "pgdir" entry.
         */
        while (length >= (PGDIR_SIZE / 2)) {
                alloc_init_section(virt, virt + off, prot_sect);

                virt   += (PGDIR_SIZE / 2);
                length -= (PGDIR_SIZE / 2);
        }

        while (length >= PAGE_SIZE) {
                alloc_init_page(virt, virt + off, prot_l1, prot_pte);

                virt   += PAGE_SIZE;
                length -= PAGE_SIZE;
        }
}

/*
 * In order to soft-boot, we need to insert a 1:1 mapping in place of
 * the user-mode pages.  This will then ensure that we have predictable
 * results when turning the mmu off
 */
void setup_mm_for_reboot(char mode)
{
        unsigned long pmdval;
        pgd_t *pgd;
        pmd_t *pmd;
        int i;
        int cpu_arch = cpu_architecture();

        if (current->mm && current->mm->pgd)
                pgd = current->mm->pgd;
        else
                pgd = init_mm.pgd;

        for (i = 0; i < FIRST_USER_PGD_NR + USER_PTRS_PER_PGD; i++) {
                pmdval = (i << PGDIR_SHIFT) |
                         PMD_SECT_AP_WRITE | PMD_SECT_AP_READ |
                         PMD_TYPE_SECT;
                if (cpu_arch <= CPU_ARCH_ARMv5)
                        pmdval |= PMD_BIT4;
                pmd = pmd_off(pgd, i << PGDIR_SHIFT);
                pmd[0] = __pmd(pmdval);
                pmd[1] = __pmd(pmdval + (1 << (PGDIR_SHIFT - 1)));
                flush_pmd_entry(pmd);
        }
}

extern void _stext, _etext;

/*
 * Setup initial mappings.  We use the page we allocated for zero page to hold
 * the mappings, which will get overwritten by the vectors in traps_init().
 * The mappings must be in virtual address order.
 */
void __init memtable_init(struct meminfo *mi)
{
        struct map_desc *init_maps, *p, *q;
        unsigned long address = 0;
        int i;

        build_mem_type_table();

        init_maps = p = alloc_bootmem_low_pages(PAGE_SIZE);

#ifdef CONFIG_XIP_KERNEL
        p->physical   = CONFIG_XIP_PHYS_ADDR & PMD_MASK;
        p->virtual    = (unsigned long)&_stext & PMD_MASK;
        p->length     = ((unsigned long)&_etext - p->virtual + ~PMD_MASK) & PMD_MASK;
        p->type       = MT_ROM;
        p ++;
#endif

        for (i = 0; i < mi->nr_banks; i++) {
                if (mi->bank[i].size == 0)
                        continue;

                p->physical   = mi->bank[i].start;
                p->virtual    = __phys_to_virt(p->physical);
                p->length     = mi->bank[i].size;
                p->type       = MT_MEMORY;
                p ++;
        }

#ifdef FLUSH_BASE
        p->physical   = FLUSH_BASE_PHYS;
        p->virtual    = FLUSH_BASE;
        p->length     = PGDIR_SIZE;
        p->type       = MT_CACHECLEAN;
        p ++;
#endif

#ifdef FLUSH_BASE_MINICACHE
        p->physical   = FLUSH_BASE_PHYS + PGDIR_SIZE;
        p->virtual    = FLUSH_BASE_MINICACHE;
        p->length     = PGDIR_SIZE;
        p->type       = MT_MINICLEAN;
        p ++;
#endif

        /*
         * Go through the initial mappings, but clear out any
         * pgdir entries that are not in the description.
         */
        q = init_maps;
        do {
                if (address < q->virtual || q == p) {
                        clear_mapping(address);
                        address += PGDIR_SIZE;
                } else {
                        create_mapping(q);

                        address = q->virtual + q->length;
                        address = (address + PGDIR_SIZE - 1) & PGDIR_MASK;

                        q ++;
                }
        } while (address != 0);

        /*
         * Create a mapping for the machine vectors at the high-vectors
         * location (0xffff0000).  If we aren't using high-vectors, also
         * create a mapping at the low-vectors virtual address.
         */
        init_maps->physical   = virt_to_phys(init_maps);
        init_maps->virtual    = 0xffff0000;
        init_maps->length     = PAGE_SIZE;
        init_maps->type       = MT_HIGH_VECTORS;
        create_mapping(init_maps);

        if (!vectors_high()) {
                init_maps->virtual = 0;
                init_maps->type = MT_LOW_VECTORS;
                create_mapping(init_maps);
        }

        flush_cache_all();
        flush_tlb_all();

        top_pmd = pmd_off_k(VECTORS_HIGH);
}

/*
 * Create the architecture specific mappings
 */
void __init iotable_init(struct map_desc *io_desc, int nr)
{
        int i;

        for (i = 0; i < nr; i++)
                create_mapping(io_desc + i);
}

static inline void
free_memmap(int node, 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);
        end_pg = pfn_to_page(end_pfn);

        /*
         * Convert to physical addresses, and
         * round start upwards and end downwards.
         */
        pg = PAGE_ALIGN(__pa(start_pg));
        pgend = __pa(end_pg) & PAGE_MASK;

        /*
         * If there are free pages between these,
         * free the section of the memmap array.
         */
        if (pg < pgend)
                free_bootmem_node(NODE_DATA(node), pg, pgend - pg);
}

static inline void free_unused_memmap_node(int node, struct meminfo *mi)
{
        unsigned long bank_start, prev_bank_end = 0;
        unsigned int i;

        /*
         * [FIXME] This relies on each bank being in address order.  This
         * may not be the case, especially if the user has provided the
         * information on the command line.
         */
        for (i = 0; i < mi->nr_banks; i++) {
                if (mi->bank[i].size == 0 || mi->bank[i].node != node)
                        continue;

                bank_start = mi->bank[i].start >> PAGE_SHIFT;
                if (bank_start < prev_bank_end) {
                        printk(KERN_ERR "MEM: unordered memory banks.  "
                                "Not freeing memmap.\n");
                        break;
                }

                /*
                 * If we had a previous bank, and there is a space
                 * between the current bank and the previous, free it.
                 */
                if (prev_bank_end && prev_bank_end != bank_start)
                        free_memmap(node, prev_bank_end, bank_start);

                prev_bank_end = PAGE_ALIGN(mi->bank[i].start +
                                           mi->bank[i].size) >> PAGE_SHIFT;
        }
}

/*
 * The mem_map array can get very big.  Free
 * the unused area of the memory map.
 */
void __init create_memmap_holes(struct meminfo *mi)
{
        int node;

        for_each_online_node(node)
                free_unused_memmap_node(node, mi);
}