hugetlbpage.c

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/*
 * PPC Huge TLB Page Support for Kernel.
 *
 * Copyright (C) 2003 David Gibson, IBM Corporation.
 * Copyright (C) 2011 Becky Bruce, Freescale Semiconductor
 *
 * Based on the IA-32 version:
 * Copyright (C) 2002, Rohit Seth <[email protected]>
 */

#include <linux/mm.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/hugetlb.h>
#include <linux/export.h>
#include <linux/of_fdt.h>
#include <linux/memblock.h>
#include <linux/bootmem.h>
#include <linux/moduleparam.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/tlb.h>
#include <asm/setup.h>

#define PAGE_SHIFT_64K  16
#define PAGE_SHIFT_16M  24
#define PAGE_SHIFT_16G  34

unsigned int HPAGE_SHIFT;

/*
 * Tracks gpages after the device tree is scanned and before the
 * huge_boot_pages list is ready.  On non-Freescale implementations, this is
 * just used to track 16G pages and so is a single array.  FSL-based
 * implementations may have more than one gpage size, so we need multiple
 * arrays
 */
#ifdef CONFIG_PPC_FSL_BOOK3E
#define MAX_NUMBER_GPAGES   128
struct psize_gpages {
    u64 gpage_list[MAX_NUMBER_GPAGES];
    unsigned int nr_gpages;
};
static struct psize_gpages gpage_freearray[MMU_PAGE_COUNT];
#else
#define MAX_NUMBER_GPAGES   1024
static u64 gpage_freearray[MAX_NUMBER_GPAGES];
static unsigned nr_gpages;
#endif

static inline int shift_to_mmu_psize(unsigned int shift)
{
    int psize;

    for (psize = 0; psize < MMU_PAGE_COUNT; ++psize)
        if (mmu_psize_defs[psize].shift == shift)
            return psize;
    return -1;
}

static inline unsigned int mmu_psize_to_shift(unsigned int mmu_psize)
{
    if (mmu_psize_defs[mmu_psize].shift)
        return mmu_psize_defs[mmu_psize].shift;
    BUG();
}

#define hugepd_none(hpd)    ((hpd).pd == 0)

pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift)
{
    pgd_t *pg;
    pud_t *pu;
    pmd_t *pm;
    hugepd_t *hpdp = NULL;
    unsigned pdshift = PGDIR_SHIFT;

    if (shift)
        *shift = 0;

    pg = pgdir + pgd_index(ea);
    if (is_hugepd(pg)) {
        hpdp = (hugepd_t *)pg;
    } else if (!pgd_none(*pg)) {
        pdshift = PUD_SHIFT;
        pu = pud_offset(pg, ea);
        if (is_hugepd(pu))
            hpdp = (hugepd_t *)pu;
        else if (!pud_none(*pu)) {
            pdshift = PMD_SHIFT;
            pm = pmd_offset(pu, ea);
            if (is_hugepd(pm))
                hpdp = (hugepd_t *)pm;
            else if (!pmd_none(*pm)) {
                return pte_offset_kernel(pm, ea);
            }
        }
    }

    if (!hpdp)
        return NULL;

    if (shift)
        *shift = hugepd_shift(*hpdp);
    return hugepte_offset(hpdp, ea, pdshift);
}
EXPORT_SYMBOL_GPL(find_linux_pte_or_hugepte);

pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
{
    return find_linux_pte_or_hugepte(mm->pgd, addr, NULL);
}

static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
               unsigned long address, unsigned pdshift, unsigned pshift)
{
    struct kmem_cache *cachep;
    pte_t *new;

#ifdef CONFIG_PPC_FSL_BOOK3E
    int i;
    int num_hugepd = 1 << (pshift - pdshift);
    cachep = hugepte_cache;
#else
    cachep = PGT_CACHE(pdshift - pshift);
#endif

    new = kmem_cache_zalloc(cachep, GFP_KERNEL|__GFP_REPEAT);

    BUG_ON(pshift > HUGEPD_SHIFT_MASK);
    BUG_ON((unsigned long)new & HUGEPD_SHIFT_MASK);

    if (! new)
        return -ENOMEM;

    spin_lock(&mm->page_table_lock);
#ifdef CONFIG_PPC_FSL_BOOK3E
    /*
     * We have multiple higher-level entries that point to the same
     * actual pte location.  Fill in each as we go and backtrack on error.
     * We need all of these so the DTLB pgtable walk code can find the
     * right higher-level entry without knowing if it's a hugepage or not.
     */
    for (i = 0; i < num_hugepd; i++, hpdp++) {
        if (unlikely(!hugepd_none(*hpdp)))
            break;
        else
            hpdp->pd = ((unsigned long)new & ~PD_HUGE) | pshift;
    }
    /* If we bailed from the for loop early, an error occurred, clean up */
    if (i < num_hugepd) {
        for (i = i - 1 ; i >= 0; i--, hpdp--)
            hpdp->pd = 0;
        kmem_cache_free(cachep, new);
    }
#else
    if (!hugepd_none(*hpdp))
        kmem_cache_free(cachep, new);
    else
        hpdp->pd = ((unsigned long)new & ~PD_HUGE) | pshift;
#endif
    spin_unlock(&mm->page_table_lock);
    return 0;
}

/*
 * These macros define how to determine which level of the page table holds
 * the hpdp.
 */
#ifdef CONFIG_PPC_FSL_BOOK3E
#define HUGEPD_PGD_SHIFT PGDIR_SHIFT
#define HUGEPD_PUD_SHIFT PUD_SHIFT
#else
#define HUGEPD_PGD_SHIFT PUD_SHIFT
#define HUGEPD_PUD_SHIFT PMD_SHIFT
#endif

pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
{
    pgd_t *pg;
    pud_t *pu;
    pmd_t *pm;
    hugepd_t *hpdp = NULL;
    unsigned pshift = __ffs(sz);
    unsigned pdshift = PGDIR_SHIFT;

    addr &= ~(sz-1);

    pg = pgd_offset(mm, addr);

    if (pshift >= HUGEPD_PGD_SHIFT) {
        hpdp = (hugepd_t *)pg;
    } else {
        pdshift = PUD_SHIFT;
        pu = pud_alloc(mm, pg, addr);
        if (pshift >= HUGEPD_PUD_SHIFT) {
            hpdp = (hugepd_t *)pu;
        } else {
            pdshift = PMD_SHIFT;
            pm = pmd_alloc(mm, pu, addr);
            hpdp = (hugepd_t *)pm;
        }
    }

    if (!hpdp)
        return NULL;

    BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp));

    if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, pdshift, pshift))
        return NULL;

    return hugepte_offset(hpdp, addr, pdshift);
}

#ifdef CONFIG_PPC_FSL_BOOK3E
/* Build list of addresses of gigantic pages.  This function is used in early
 * boot before the buddy or bootmem allocator is setup.
 */
void add_gpage(u64 addr, u64 page_size, unsigned long number_of_pages)
{
    unsigned int idx = shift_to_mmu_psize(__ffs(page_size));
    int i;

    if (addr == 0)
        return;

    gpage_freearray[idx].nr_gpages = number_of_pages;

    for (i = 0; i < number_of_pages; i++) {
        gpage_freearray[idx].gpage_list[i] = addr;
        addr += page_size;
    }
}

/*
 * Moves the gigantic page addresses from the temporary list to the
 * huge_boot_pages list.
 */
int alloc_bootmem_huge_page(struct hstate *hstate)
{
    struct huge_bootmem_page *m;
    int idx = shift_to_mmu_psize(hstate->order + PAGE_SHIFT);
    int nr_gpages = gpage_freearray[idx].nr_gpages;

    if (nr_gpages == 0)
        return 0;

#ifdef CONFIG_HIGHMEM
    /*
     * If gpages can be in highmem we can't use the trick of storing the
     * data structure in the page; allocate space for this
     */
    m = alloc_bootmem(sizeof(struct huge_bootmem_page));
    m->phys = gpage_freearray[idx].gpage_list[--nr_gpages];
#else
    m = phys_to_virt(gpage_freearray[idx].gpage_list[--nr_gpages]);
#endif

    list_add(&m->list, &huge_boot_pages);
    gpage_freearray[idx].nr_gpages = nr_gpages;
    gpage_freearray[idx].gpage_list[nr_gpages] = 0;
    m->hstate = hstate;

    return 1;
}
/*
 * Scan the command line hugepagesz= options for gigantic pages; store those in
 * a list that we use to allocate the memory once all options are parsed.
 */

unsigned long gpage_npages[MMU_PAGE_COUNT];

static int __init do_gpage_early_setup(char *param, char *val,
                       const char *unused)
{
    static phys_addr_t size;
    unsigned long npages;

    /*
     * The hugepagesz and hugepages cmdline options are interleaved.  We
     * use the size variable to keep track of whether or not this was done
     * properly and skip over instances where it is incorrect.  Other
     * command-line parsing code will issue warnings, so we don't need to.
     *
     */
    if ((strcmp(param, "default_hugepagesz") == 0) ||
        (strcmp(param, "hugepagesz") == 0)) {
        size = memparse(val, NULL);
    } else if (strcmp(param, "hugepages") == 0) {
        if (size != 0) {
            if (sscanf(val, "%lu", &npages) <= 0)
                npages = 0;
            gpage_npages[shift_to_mmu_psize(__ffs(size))] = npages;
            size = 0;
        }
    }
    return 0;
}


/*
 * This function allocates physical space for pages that are larger than the
 * buddy allocator can handle.  We want to allocate these in highmem because
 * the amount of lowmem is limited.  This means that this function MUST be
 * called before lowmem_end_addr is set up in MMU_init() in order for the lmb
 * allocate to grab highmem.
 */
void __init reserve_hugetlb_gpages(void)
{
    static __initdata char cmdline[COMMAND_LINE_SIZE];
    phys_addr_t size, base;
    int i;

    strlcpy(cmdline, boot_command_line, COMMAND_LINE_SIZE);
    parse_args("hugetlb gpages", cmdline, NULL, 0, 0, 0,
            &do_gpage_early_setup);

    /*
     * Walk gpage list in reverse, allocating larger page sizes first.
     * Skip over unsupported sizes, or sizes that have 0 gpages allocated.
     * When we reach the point in the list where pages are no longer
     * considered gpages, we're done.
     */
    for (i = MMU_PAGE_COUNT-1; i >= 0; i--) {
        if (mmu_psize_defs[i].shift == 0 || gpage_npages[i] == 0)
            continue;
        else if (mmu_psize_to_shift(i) < (MAX_ORDER + PAGE_SHIFT))
            break;

        size = (phys_addr_t)(1ULL << mmu_psize_to_shift(i));
        base = memblock_alloc_base(size * gpage_npages[i], size,
                       MEMBLOCK_ALLOC_ANYWHERE);
        add_gpage(base, size, gpage_npages[i]);
    }
}

#else /* !PPC_FSL_BOOK3E */

/* Build list of addresses of gigantic pages.  This function is used in early
 * boot before the buddy or bootmem allocator is setup.
 */
void add_gpage(u64 addr, u64 page_size, unsigned long number_of_pages)
{
    if (!addr)
        return;
    while (number_of_pages > 0) {
        gpage_freearray[nr_gpages] = addr;
        nr_gpages++;
        number_of_pages--;
        addr += page_size;
    }
}

/* Moves the gigantic page addresses from the temporary list to the
 * huge_boot_pages list.
 */
int alloc_bootmem_huge_page(struct hstate *hstate)
{
    struct huge_bootmem_page *m;
    if (nr_gpages == 0)
        return 0;
    m = phys_to_virt(gpage_freearray[--nr_gpages]);
    gpage_freearray[nr_gpages] = 0;
    list_add(&m->list, &huge_boot_pages);
    m->hstate = hstate;
    return 1;
}
#endif

int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
{
    return 0;
}

#ifdef CONFIG_PPC_FSL_BOOK3E
#define HUGEPD_FREELIST_SIZE \
    ((PAGE_SIZE - sizeof(struct hugepd_freelist)) / sizeof(pte_t))

struct hugepd_freelist {
    struct rcu_head rcu;
    unsigned int index;
    void *ptes[0];
};

static DEFINE_PER_CPU(struct hugepd_freelist *, hugepd_freelist_cur);

static void hugepd_free_rcu_callback(struct rcu_head *head)
{
    struct hugepd_freelist *batch =
        container_of(head, struct hugepd_freelist, rcu);
    unsigned int i;

    for (i = 0; i < batch->index; i++)
        kmem_cache_free(hugepte_cache, batch->ptes[i]);

    free_page((unsigned long)batch);
}

static void hugepd_free(struct mmu_gather *tlb, void *hugepte)
{
    struct hugepd_freelist **batchp;

    batchp = &__get_cpu_var(hugepd_freelist_cur);

    if (atomic_read(&tlb->mm->mm_users) < 2 ||
        cpumask_equal(mm_cpumask(tlb->mm),
              cpumask_of(smp_processor_id()))) {
        kmem_cache_free(hugepte_cache, hugepte);
        return;
    }

    if (*batchp == NULL) {
        *batchp = (struct hugepd_freelist *)__get_free_page(GFP_ATOMIC);
        (*batchp)->index = 0;
    }

    (*batchp)->ptes[(*batchp)->index++] = hugepte;
    if ((*batchp)->index == HUGEPD_FREELIST_SIZE) {
        call_rcu_sched(&(*batchp)->rcu, hugepd_free_rcu_callback);
        *batchp = NULL;
    }
}
#endif

static void free_hugepd_range(struct mmu_gather *tlb, hugepd_t *hpdp, int pdshift,
                  unsigned long start, unsigned long end,
                  unsigned long floor, unsigned long ceiling)
{
    pte_t *hugepte = hugepd_page(*hpdp);
    int i;

    unsigned long pdmask = ~((1UL << pdshift) - 1);
    unsigned int num_hugepd = 1;

#ifdef CONFIG_PPC_FSL_BOOK3E
    /* Note: On fsl the hpdp may be the first of several */
    num_hugepd = (1 << (hugepd_shift(*hpdp) - pdshift));
#else
    unsigned int shift = hugepd_shift(*hpdp);
#endif

    start &= pdmask;
    if (start < floor)
        return;
    if (ceiling) {
        ceiling &= pdmask;
        if (! ceiling)
            return;
    }
    if (end - 1 > ceiling - 1)
        return;

    for (i = 0; i < num_hugepd; i++, hpdp++)
        hpdp->pd = 0;

    tlb->need_flush = 1;

#ifdef CONFIG_PPC_FSL_BOOK3E
    hugepd_free(tlb, hugepte);
#else
    pgtable_free_tlb(tlb, hugepte, pdshift - shift);
#endif
}

static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
                   unsigned long addr, unsigned long end,
                   unsigned long floor, unsigned long ceiling)
{
    pmd_t *pmd;
    unsigned long next;
    unsigned long start;

    start = addr;
    do {
        pmd = pmd_offset(pud, addr);
        next = pmd_addr_end(addr, end);
        if (pmd_none(*pmd))
            continue;
#ifdef CONFIG_PPC_FSL_BOOK3E
        /*
         * Increment next by the size of the huge mapping since
         * there may be more than one entry at this level for a
         * single hugepage, but all of them point to
         * the same kmem cache that holds the hugepte.
         */
        next = addr + (1 << hugepd_shift(*(hugepd_t *)pmd));
#endif
        free_hugepd_range(tlb, (hugepd_t *)pmd, PMD_SHIFT,
                  addr, next, floor, ceiling);
    } while (addr = next, addr != end);

    start &= PUD_MASK;
    if (start < floor)
        return;
    if (ceiling) {
        ceiling &= PUD_MASK;
        if (!ceiling)
            return;
    }
    if (end - 1 > ceiling - 1)
        return;

    pmd = pmd_offset(pud, start);
    pud_clear(pud);
    pmd_free_tlb(tlb, pmd, start);
}

static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
                   unsigned long addr, unsigned long end,
                   unsigned long floor, unsigned long ceiling)
{
    pud_t *pud;
    unsigned long next;
    unsigned long start;

    start = addr;
    do {
        pud = pud_offset(pgd, addr);
        next = pud_addr_end(addr, end);
        if (!is_hugepd(pud)) {
            if (pud_none_or_clear_bad(pud))
                continue;
            hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
                           ceiling);
        } else {
#ifdef CONFIG_PPC_FSL_BOOK3E
            /*
             * Increment next by the size of the huge mapping since
             * there may be more than one entry at this level for a
             * single hugepage, but all of them point to
             * the same kmem cache that holds the hugepte.
             */
            next = addr + (1 << hugepd_shift(*(hugepd_t *)pud));
#endif
            free_hugepd_range(tlb, (hugepd_t *)pud, PUD_SHIFT,
                      addr, next, floor, ceiling);
        }
    } while (addr = next, addr != end);

    start &= PGDIR_MASK;
    if (start < floor)
        return;
    if (ceiling) {
        ceiling &= PGDIR_MASK;
        if (!ceiling)
            return;
    }
    if (end - 1 > ceiling - 1)
        return;

    pud = pud_offset(pgd, start);
    pgd_clear(pgd);
    pud_free_tlb(tlb, pud, start);
}

/*
 * This function frees user-level page tables of a process.
 *
 * Must be called with pagetable lock held.
 */
void hugetlb_free_pgd_range(struct mmu_gather *tlb,
                unsigned long addr, unsigned long end,
                unsigned long floor, unsigned long ceiling)
{
    pgd_t *pgd;
    unsigned long next;

    /*
     * Because there are a number of different possible pagetable
     * layouts for hugepage ranges, we limit knowledge of how
     * things should be laid out to the allocation path
     * (huge_pte_alloc(), above).  Everything else works out the
     * structure as it goes from information in the hugepd
     * pointers.  That means that we can't here use the
     * optimization used in the normal page free_pgd_range(), of
     * checking whether we're actually covering a large enough
     * range to have to do anything at the top level of the walk
     * instead of at the bottom.
     *
     * To make sense of this, you should probably go read the big
     * block comment at the top of the normal free_pgd_range(),
     * too.
     */

    do {
        next = pgd_addr_end(addr, end);
        pgd = pgd_offset(tlb->mm, addr);
        if (!is_hugepd(pgd)) {
            if (pgd_none_or_clear_bad(pgd))
                continue;
            hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling);
        } else {
#ifdef CONFIG_PPC_FSL_BOOK3E
            /*
             * Increment next by the size of the huge mapping since
             * there may be more than one entry at the pgd level
             * for a single hugepage, but all of them point to the
             * same kmem cache that holds the hugepte.
             */
            next = addr + (1 << hugepd_shift(*(hugepd_t *)pgd));
#endif
            free_hugepd_range(tlb, (hugepd_t *)pgd, PGDIR_SHIFT,
                      addr, next, floor, ceiling);
        }
    } while (addr = next, addr != end);
}

struct page *
follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
{
    pte_t *ptep;
    struct page *page;
    unsigned shift;
    unsigned long mask;

    ptep = find_linux_pte_or_hugepte(mm->pgd, address, &shift);

    /* Verify it is a huge page else bail. */
    if (!ptep || !shift)
        return ERR_PTR(-EINVAL);

    mask = (1UL << shift) - 1;
    page = pte_page(*ptep);
    if (page)
        page += (address & mask) / PAGE_SIZE;

    return page;
}

int pmd_huge(pmd_t pmd)
{
    return 0;
}

int pud_huge(pud_t pud)
{
    return 0;
}

struct page *
follow_huge_pmd(struct mm_struct *mm, unsigned long address,
        pmd_t *pmd, int write)
{
    BUG();
    return NULL;
}

static noinline int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
               unsigned long end, int write, struct page **pages, int *nr)
{
    unsigned long mask;
    unsigned long pte_end;
    struct page *head, *page, *tail;
    pte_t pte;
    int refs;

    pte_end = (addr + sz) & ~(sz-1);
    if (pte_end < end)
        end = pte_end;

    pte = *ptep;
    mask = _PAGE_PRESENT | _PAGE_USER;
    if (write)
        mask |= _PAGE_RW;

    if ((pte_val(pte) & mask) != mask)
        return 0;

    /* hugepages are never "special" */
    VM_BUG_ON(!pfn_valid(pte_pfn(pte)));

    refs = 0;
    head = pte_page(pte);

    page = head + ((addr & (sz-1)) >> PAGE_SHIFT);
    tail = page;
    do {
        VM_BUG_ON(compound_head(page) != head);
        pages[*nr] = page;
        (*nr)++;
        page++;
        refs++;
    } while (addr += PAGE_SIZE, addr != end);

    if (!page_cache_add_speculative(head, refs)) {
        *nr -= refs;
        return 0;
    }

    if (unlikely(pte_val(pte) != pte_val(*ptep))) {
        /* Could be optimized better */
        *nr -= refs;
        while (refs--)
            put_page(head);
        return 0;
    }

    /*
     * Any tail page need their mapcount reference taken before we
     * return.
     */
    while (refs--) {
        if (PageTail(tail))
            get_huge_page_tail(tail);
        tail++;
    }

    return 1;
}

static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end,
                      unsigned long sz)
{
    unsigned long __boundary = (addr + sz) & ~(sz-1);
    return (__boundary - 1 < end - 1) ? __boundary : end;
}

int gup_hugepd(hugepd_t *hugepd, unsigned pdshift,
           unsigned long addr, unsigned long end,
           int write, struct page **pages, int *nr)
{
    pte_t *ptep;
    unsigned long sz = 1UL << hugepd_shift(*hugepd);
    unsigned long next;

    ptep = hugepte_offset(hugepd, addr, pdshift);
    do {
        next = hugepte_addr_end(addr, end, sz);
        if (!gup_hugepte(ptep, sz, addr, end, write, pages, nr))
            return 0;
    } while (ptep++, addr = next, addr != end);

    return 1;
}

#ifdef CONFIG_PPC_MM_SLICES
unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
                    unsigned long len, unsigned long pgoff,
                    unsigned long flags)
{
    struct hstate *hstate = hstate_file(file);
    int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate));

    return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1, 0);
}
#endif

unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
{
#ifdef CONFIG_PPC_MM_SLICES
    unsigned int psize = get_slice_psize(vma->vm_mm, vma->vm_start);

    return 1UL << mmu_psize_to_shift(psize);
#else
    if (!is_vm_hugetlb_page(vma))
        return PAGE_SIZE;

    return huge_page_size(hstate_vma(vma));
#endif
}

static inline bool is_power_of_4(unsigned long x)
{
    if (is_power_of_2(x))
        return (__ilog2(x) % 2) ? false : true;
    return false;
}

static int __init add_huge_page_size(unsigned long long size)
{
    int shift = __ffs(size);
    int mmu_psize;

    /* Check that it is a page size supported by the hardware and
     * that it fits within pagetable and slice limits. */
#ifdef CONFIG_PPC_FSL_BOOK3E
    if ((size < PAGE_SIZE) || !is_power_of_4(size))
        return -EINVAL;
#else
    if (!is_power_of_2(size)
        || (shift > SLICE_HIGH_SHIFT) || (shift <= PAGE_SHIFT))
        return -EINVAL;
#endif

    if ((mmu_psize = shift_to_mmu_psize(shift)) < 0)
        return -EINVAL;

#ifdef CONFIG_SPU_FS_64K_LS
    /* Disable support for 64K huge pages when 64K SPU local store
     * support is enabled as the current implementation conflicts.
     */
    if (shift == PAGE_SHIFT_64K)
        return -EINVAL;
#endif /* CONFIG_SPU_FS_64K_LS */

    BUG_ON(mmu_psize_defs[mmu_psize].shift != shift);

    /* Return if huge page size has already been setup */
    if (size_to_hstate(size))
        return 0;

    hugetlb_add_hstate(shift - PAGE_SHIFT);

    return 0;
}

static int __init hugepage_setup_sz(char *str)
{
    unsigned long long size;

    size = memparse(str, &str);

    if (add_huge_page_size(size) != 0)
        printk(KERN_WARNING "Invalid huge page size specified(%llu)\n", size);

    return 1;
}
__setup("hugepagesz=", hugepage_setup_sz);

#ifdef CONFIG_PPC_FSL_BOOK3E
struct kmem_cache *hugepte_cache;
static int __init hugetlbpage_init(void)
{
    int psize;

    for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
        unsigned shift;

        if (!mmu_psize_defs[psize].shift)
            continue;

        shift = mmu_psize_to_shift(psize);

        /* Don't treat normal page sizes as huge... */
        if (shift != PAGE_SHIFT)
            if (add_huge_page_size(1ULL << shift) < 0)
                continue;
    }

    /*
     * Create a kmem cache for hugeptes.  The bottom bits in the pte have
     * size information encoded in them, so align them to allow this
     */
    hugepte_cache =  kmem_cache_create("hugepte-cache", sizeof(pte_t),
                       HUGEPD_SHIFT_MASK + 1, 0, NULL);
    if (hugepte_cache == NULL)
        panic("%s: Unable to create kmem cache for hugeptes\n",
              __func__);

    /* Default hpage size = 4M */
    if (mmu_psize_defs[MMU_PAGE_4M].shift)
        HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_4M].shift;
    else
        panic("%s: Unable to set default huge page size\n", __func__);


    return 0;
}
#else
static int __init hugetlbpage_init(void)
{
    int psize;

    if (!mmu_has_feature(MMU_FTR_16M_PAGE))
        return -ENODEV;

    for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
        unsigned shift;
        unsigned pdshift;

        if (!mmu_psize_defs[psize].shift)
            continue;

        shift = mmu_psize_to_shift(psize);

        if (add_huge_page_size(1ULL << shift) < 0)
            continue;

        if (shift < PMD_SHIFT)
            pdshift = PMD_SHIFT;
        else if (shift < PUD_SHIFT)
            pdshift = PUD_SHIFT;
        else
            pdshift = PGDIR_SHIFT;

        pgtable_cache_add(pdshift - shift, NULL);
        if (!PGT_CACHE(pdshift - shift))
            panic("hugetlbpage_init(): could not create "
                  "pgtable cache for %d bit pagesize\n", shift);
    }

    /* Set default large page size. Currently, we pick 16M or 1M
     * depending on what is available
     */
    if (mmu_psize_defs[MMU_PAGE_16M].shift)
        HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_16M].shift;
    else if (mmu_psize_defs[MMU_PAGE_1M].shift)
        HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_1M].shift;

    return 0;
}
#endif
module_init(hugetlbpage_init);

void flush_dcache_icache_hugepage(struct page *page)
{
    int i;
    void *start;

    BUG_ON(!PageCompound(page));

    for (i = 0; i < (1UL << compound_order(page)); i++) {
        if (!PageHighMem(page)) {
            __flush_dcache_icache(page_address(page+i));
        } else {
            start = kmap_atomic(page+i);
            __flush_dcache_icache(start);
            kunmap_atomic(start);
        }
    }
}