[deliverable/linux.git] / arch / x86 / mm / hugetlbpage.c

/*
 * IA-32 Huge TLB Page Support for Kernel.
 *
 * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
 */

#include <linux/init.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/sysctl.h>
#include <asm/mman.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/pgalloc.h>

static unsigned long page_table_shareable(struct vm_area_struct *svma,
				struct vm_area_struct *vma,
				unsigned long addr, pgoff_t idx)
{
	unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
				svma->vm_start;
	unsigned long sbase = saddr & PUD_MASK;
	unsigned long s_end = sbase + PUD_SIZE;

	/* Allow segments to share if only one is marked locked */
	unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED;
	unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED;

	/*
	 * match the virtual addresses, permission and the alignment of the
	 * page table page.
	 */
	if (pmd_index(addr) != pmd_index(saddr) ||
	    vm_flags != svm_flags ||
	    sbase < svma->vm_start || svma->vm_end < s_end)
		return 0;

	return saddr;
}

static int vma_shareable(struct vm_area_struct *vma, unsigned long addr)
{
	unsigned long base = addr & PUD_MASK;
	unsigned long end = base + PUD_SIZE;

	/*
	 * check on proper vm_flags and page table alignment
	 */
	if (vma->vm_flags & VM_MAYSHARE &&
	    vma->vm_start <= base && end <= vma->vm_end)
		return 1;
	return 0;
}

/*
 * search for a shareable pmd page for hugetlb.
 */
static void huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
{
	struct vm_area_struct *vma = find_vma(mm, addr);
	struct address_space *mapping = vma->vm_file->f_mapping;
	pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
			vma->vm_pgoff;
	struct prio_tree_iter iter;
	struct vm_area_struct *svma;
	unsigned long saddr;
	pte_t *spte = NULL;

	if (!vma_shareable(vma, addr))
		return;

	spin_lock(&mapping->i_mmap_lock);
	vma_prio_tree_foreach(svma, &iter, &mapping->i_mmap, idx, idx) {
		if (svma == vma)
			continue;

		saddr = page_table_shareable(svma, vma, addr, idx);
		if (saddr) {
			spte = huge_pte_offset(svma->vm_mm, saddr);
			if (spte) {
				get_page(virt_to_page(spte));
				break;
			}
		}
	}

	if (!spte)
		goto out;

	spin_lock(&mm->page_table_lock);
	if (pud_none(*pud))
		pud_populate(mm, pud, (pmd_t *)((unsigned long)spte & PAGE_MASK));
	else
		put_page(virt_to_page(spte));
	spin_unlock(&mm->page_table_lock);
out:
	spin_unlock(&mapping->i_mmap_lock);
}

/*
 * unmap huge page backed by shared pte.
 *
 * Hugetlb pte page is ref counted at the time of mapping.  If pte is shared
 * indicated by page_count > 1, unmap is achieved by clearing pud and
 * decrementing the ref count. If count == 1, the pte page is not shared.
 *
 * called with vma->vm_mm->page_table_lock held.
 *
 * returns: 1 successfully unmapped a shared pte page
 *	    0 the underlying pte page is not shared, or it is the last user
 */
int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
{
	pgd_t *pgd = pgd_offset(mm, *addr);
	pud_t *pud = pud_offset(pgd, *addr);

	BUG_ON(page_count(virt_to_page(ptep)) == 0);
	if (page_count(virt_to_page(ptep)) == 1)
		return 0;

	pud_clear(pud);
	put_page(virt_to_page(ptep));
	*addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
	return 1;
}

pte_t *huge_pte_alloc(struct mm_struct *mm,
			unsigned long addr, unsigned long sz)
{
	pgd_t *pgd;
	pud_t *pud;
	pte_t *pte = NULL;

	pgd = pgd_offset(mm, addr);
	pud = pud_alloc(mm, pgd, addr);
	if (pud) {
		if (sz == PUD_SIZE) {
			pte = (pte_t *)pud;
		} else {
			BUG_ON(sz != PMD_SIZE);
			if (pud_none(*pud))
				huge_pmd_share(mm, addr, pud);
			pte = (pte_t *) pmd_alloc(mm, pud, addr);
		}
	}
	BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte));

	return pte;
}

pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
{
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd = NULL;

	pgd = pgd_offset(mm, addr);
	if (pgd_present(*pgd)) {
		pud = pud_offset(pgd, addr);
		if (pud_present(*pud)) {
			if (pud_large(*pud))
				return (pte_t *)pud;
			pmd = pmd_offset(pud, addr);
		}
	}
	return (pte_t *) pmd;
}

#if 0	/* This is just for testing */
struct page *
follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
{
	unsigned long start = address;
	int length = 1;
	int nr;
	struct page *page;
	struct vm_area_struct *vma;

	vma = find_vma(mm, addr);
	if (!vma || !is_vm_hugetlb_page(vma))
		return ERR_PTR(-EINVAL);

	pte = huge_pte_offset(mm, address);

	/* hugetlb should be locked, and hence, prefaulted */
	WARN_ON(!pte || pte_none(*pte));

	page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];

	WARN_ON(!PageHead(page));

	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)
{
	return NULL;
}

#else

struct page *
follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
{
	return ERR_PTR(-EINVAL);
}

int pmd_huge(pmd_t pmd)
{
	return !!(pmd_val(pmd) & _PAGE_PSE);
}

int pud_huge(pud_t pud)
{
	return !!(pud_val(pud) & _PAGE_PSE);
}

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

	page = pte_page(*(pte_t *)pmd);
	if (page)
		page += ((address & ~PMD_MASK) >> PAGE_SHIFT);
	return page;
}

struct page *
follow_huge_pud(struct mm_struct *mm, unsigned long address,
		pud_t *pud, int write)
{
	struct page *page;

	page = pte_page(*(pte_t *)pud);
	if (page)
		page += ((address & ~PUD_MASK) >> PAGE_SHIFT);
	return page;
}

#endif

/* x86_64 also uses this file */

#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
		unsigned long addr, unsigned long len,
		unsigned long pgoff, unsigned long flags)
{
	struct hstate *h = hstate_file(file);
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma;
	unsigned long start_addr;

	if (len > mm->cached_hole_size) {
	        start_addr = mm->free_area_cache;
	} else {
	        start_addr = TASK_UNMAPPED_BASE;
	        mm->cached_hole_size = 0;
	}

full_search:
	addr = ALIGN(start_addr, huge_page_size(h));

	for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
		/* At this point:  (!vma || addr < vma->vm_end). */
		if (TASK_SIZE - len < addr) {
			/*
			 * Start a new search - just in case we missed
			 * some holes.
			 */
			if (start_addr != TASK_UNMAPPED_BASE) {
				start_addr = TASK_UNMAPPED_BASE;
				mm->cached_hole_size = 0;
				goto full_search;
			}
			return -ENOMEM;
		}
		if (!vma || addr + len <= vma->vm_start) {
			mm->free_area_cache = addr + len;
			return addr;
		}
		if (addr + mm->cached_hole_size < vma->vm_start)
		        mm->cached_hole_size = vma->vm_start - addr;
		addr = ALIGN(vma->vm_end, huge_page_size(h));
	}
}

static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
		unsigned long addr0, unsigned long len,
		unsigned long pgoff, unsigned long flags)
{
	struct hstate *h = hstate_file(file);
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma, *prev_vma;
	unsigned long base = mm->mmap_base, addr = addr0;
	unsigned long largest_hole = mm->cached_hole_size;
	int first_time = 1;

	/* don't allow allocations above current base */
	if (mm->free_area_cache > base)
		mm->free_area_cache = base;

	if (len <= largest_hole) {
	        largest_hole = 0;
		mm->free_area_cache  = base;
	}
try_again:
	/* make sure it can fit in the remaining address space */
	if (mm->free_area_cache < len)
		goto fail;

	/* either no address requested or cant fit in requested address hole */
	addr = (mm->free_area_cache - len) & huge_page_mask(h);
	do {
		/*
		 * Lookup failure means no vma is above this address,
		 * i.e. return with success:
		 */
		if (!(vma = find_vma_prev(mm, addr, &prev_vma)))
			return addr;

		/*
		 * new region fits between prev_vma->vm_end and
		 * vma->vm_start, use it:
		 */
		if (addr + len <= vma->vm_start &&
		            (!prev_vma || (addr >= prev_vma->vm_end))) {
			/* remember the address as a hint for next time */
		        mm->cached_hole_size = largest_hole;
		        return (mm->free_area_cache = addr);
		} else {
			/* pull free_area_cache down to the first hole */
		        if (mm->free_area_cache == vma->vm_end) {
				mm->free_area_cache = vma->vm_start;
				mm->cached_hole_size = largest_hole;
			}
		}

		/* remember the largest hole we saw so far */
		if (addr + largest_hole < vma->vm_start)
		        largest_hole = vma->vm_start - addr;

		/* try just below the current vma->vm_start */
		addr = (vma->vm_start - len) & huge_page_mask(h);
	} while (len <= vma->vm_start);

fail:
	/*
	 * if hint left us with no space for the requested
	 * mapping then try again:
	 */
	if (first_time) {
		mm->free_area_cache = base;
		largest_hole = 0;
		first_time = 0;
		goto try_again;
	}
	/*
	 * A failed mmap() very likely causes application failure,
	 * so fall back to the bottom-up function here. This scenario
	 * can happen with large stack limits and large mmap()
	 * allocations.
	 */
	mm->free_area_cache = TASK_UNMAPPED_BASE;
	mm->cached_hole_size = ~0UL;
	addr = hugetlb_get_unmapped_area_bottomup(file, addr0,
			len, pgoff, flags);

	/*
	 * Restore the topdown base:
	 */
	mm->free_area_cache = base;
	mm->cached_hole_size = ~0UL;

	return addr;
}

unsigned long
hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
		unsigned long len, unsigned long pgoff, unsigned long flags)
{
	struct hstate *h = hstate_file(file);
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma;

	if (len & ~huge_page_mask(h))
		return -EINVAL;
	if (len > TASK_SIZE)
		return -ENOMEM;

	if (flags & MAP_FIXED) {
		if (prepare_hugepage_range(file, addr, len))
			return -EINVAL;
		return addr;
	}

	if (addr) {
		addr = ALIGN(addr, huge_page_size(h));
		vma = find_vma(mm, addr);
		if (TASK_SIZE - len >= addr &&
		    (!vma || addr + len <= vma->vm_start))
			return addr;
	}
	if (mm->get_unmapped_area == arch_get_unmapped_area)
		return hugetlb_get_unmapped_area_bottomup(file, addr, len,
				pgoff, flags);
	else
		return hugetlb_get_unmapped_area_topdown(file, addr, len,
				pgoff, flags);
}

#endif /*HAVE_ARCH_HUGETLB_UNMAPPED_AREA*/

#ifdef CONFIG_X86_64
static __init int setup_hugepagesz(char *opt)
{
	unsigned long ps = memparse(opt, &opt);
	if (ps == PMD_SIZE) {
		hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
	} else if (ps == PUD_SIZE && cpu_has_gbpages) {
		hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
	} else {
		printk(KERN_ERR "hugepagesz: Unsupported page size %lu M\n",
			ps >> 20);
		return 0;
	}
	return 1;
}
__setup("hugepagesz=", setup_hugepagesz);
#endif
Commit	Line	Data
1da177e4 LT	1	/*
	2	* IA-32 Huge TLB Page Support for Kernel.
	3	*
	4	* Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
	5	*/
	6
1da177e4 LT	7	#include <linux/init.h>
	8	#include <linux/fs.h>
	9	#include <linux/mm.h>
	10	#include <linux/hugetlb.h>
	11	#include <linux/pagemap.h>
1da177e4 LT	12	#include <linux/slab.h>
	13	#include <linux/err.h>
	14	#include <linux/sysctl.h>
	15	#include <asm/mman.h>
	16	#include <asm/tlb.h>
	17	#include <asm/tlbflush.h>
a5a19c63	18	#include <asm/pgalloc.h>
1da177e4	19
39dde65c CK	20	static unsigned long page_table_shareable(struct vm_area_struct *svma,
	21	struct vm_area_struct *vma,
	22	unsigned long addr, pgoff_t idx)
	23	{
	24	unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
	25	svma->vm_start;
	26	unsigned long sbase = saddr & PUD_MASK;
	27	unsigned long s_end = sbase + PUD_SIZE;
	28
32b154c0 MG	29	/* Allow segments to share if only one is marked locked */
	30	unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED;
	31	unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED;
	32
39dde65c CK	33	/*
	34	* match the virtual addresses, permission and the alignment of the
	35	* page table page.
	36	*/
	37	if (pmd_index(addr) != pmd_index(saddr) \|\|
32b154c0	38	vm_flags != svm_flags \|\|
39dde65c CK	39	sbase < svma->vm_start \|\| svma->vm_end < s_end)
	40	return 0;
	41
	42	return saddr;
	43	}
	44
	45	static int vma_shareable(struct vm_area_struct *vma, unsigned long addr)
	46	{
	47	unsigned long base = addr & PUD_MASK;
	48	unsigned long end = base + PUD_SIZE;
	49
	50	/*
	51	* check on proper vm_flags and page table alignment
	52	*/
	53	if (vma->vm_flags & VM_MAYSHARE &&
	54	vma->vm_start <= base && end <= vma->vm_end)
	55	return 1;
	56	return 0;
	57	}
	58
	59	/*
	60	* search for a shareable pmd page for hugetlb.
	61	*/
	62	static void huge_pmd_share(struct mm_struct mm, unsigned long addr, pud_t pud)
	63	{
	64	struct vm_area_struct *vma = find_vma(mm, addr);
	65	struct address_space *mapping = vma->vm_file->f_mapping;
	66	pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
	67	vma->vm_pgoff;
	68	struct prio_tree_iter iter;
	69	struct vm_area_struct *svma;
	70	unsigned long saddr;
	71	pte_t *spte = NULL;
	72
	73	if (!vma_shareable(vma, addr))
	74	return;
	75
	76	spin_lock(&mapping->i_mmap_lock);
	77	vma_prio_tree_foreach(svma, &iter, &mapping->i_mmap, idx, idx) {
	78	if (svma == vma)
	79	continue;
	80
	81	saddr = page_table_shareable(svma, vma, addr, idx);
	82	if (saddr) {
	83	spte = huge_pte_offset(svma->vm_mm, saddr);
	84	if (spte) {
	85	get_page(virt_to_page(spte));
	86	break;
	87	}
	88	}
	89	}
	90
	91	if (!spte)
	92	goto out;
	93
	94	spin_lock(&mm->page_table_lock);
	95	if (pud_none(*pud))
a5a19c63	96	pud_populate(mm, pud, (pmd_t *)((unsigned long)spte & PAGE_MASK));
39dde65c CK	97	else
	98	put_page(virt_to_page(spte));
	99	spin_unlock(&mm->page_table_lock);
	100	out:
	101	spin_unlock(&mapping->i_mmap_lock);
	102	}
	103
	104	/*
	105	* unmap huge page backed by shared pte.
	106	*
	107	* Hugetlb pte page is ref counted at the time of mapping. If pte is shared
	108	* indicated by page_count > 1, unmap is achieved by clearing pud and
	109	* decrementing the ref count. If count == 1, the pte page is not shared.
	110	*
	111	* called with vma->vm_mm->page_table_lock held.
	112	*
	113	* returns: 1 successfully unmapped a shared pte page
	114	* 0 the underlying pte page is not shared, or it is the last user
	115	*/
	116	int huge_pmd_unshare(struct mm_struct mm, unsigned long addr, pte_t *ptep)
	117	{
	118	pgd_t pgd = pgd_offset(mm, addr);
	119	pud_t pud = pud_offset(pgd, addr);
	120
	121	BUG_ON(page_count(virt_to_page(ptep)) == 0);
	122	if (page_count(virt_to_page(ptep)) == 1)
	123	return 0;
	124
	125	pud_clear(pud);
	126	put_page(virt_to_page(ptep));
	127	addr = ALIGN(addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
	128	return 1;
	129	}
	130
a5516438 AK	131	pte_t huge_pte_alloc(struct mm_struct mm,
a5516438 AK	132	unsigned long addr, unsigned long sz)
1da177e4 LT	133	{
	134	pgd_t *pgd;
	135	pud_t *pud;
7bf07f3d	136	pte_t *pte = NULL;
1da177e4 LT	137
	138	pgd = pgd_offset(mm, addr);
	139	pud = pud_alloc(mm, pgd, addr);
39dde65c	140	if (pud) {
39c11e6c AK	141	if (sz == PUD_SIZE) {
	142	pte = (pte_t *)pud;
	143	} else {
	144	BUG_ON(sz != PMD_SIZE);
	145	if (pud_none(*pud))
	146	huge_pmd_share(mm, addr, pud);
	147	pte = (pte_t *) pmd_alloc(mm, pud, addr);
	148	}
39dde65c	149	}
0e5c9f39	150	BUG_ON(pte && !pte_none(pte) && !pte_huge(pte));
7bf07f3d	151
7bf07f3d	152	return pte;
1da177e4 LT	153	}
1da177e4 LT	154
63551ae0	155	pte_t huge_pte_offset(struct mm_struct mm, unsigned long addr)
1da177e4 LT	156	{
	157	pgd_t *pgd;
	158	pud_t *pud;
	159	pmd_t *pmd = NULL;
	160
	161	pgd = pgd_offset(mm, addr);
02b0ccef AL	162	if (pgd_present(*pgd)) {
02b0ccef AL	163	pud = pud_offset(pgd, addr);
39c11e6c AK	164	if (pud_present(*pud)) {
	165	if (pud_large(*pud))
	166	return (pte_t *)pud;
02b0ccef	167	pmd = pmd_offset(pud, addr);
39c11e6c	168	}
02b0ccef	169	}
1da177e4 LT	170	return (pte_t *) pmd;
	171	}
	172
1da177e4 LT	173	#if 0 /* This is just for testing */
	174	struct page *
	175	follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
	176	{
	177	unsigned long start = address;
	178	int length = 1;
	179	int nr;
	180	struct page *page;
	181	struct vm_area_struct *vma;
	182
	183	vma = find_vma(mm, addr);
	184	if (!vma \|\| !is_vm_hugetlb_page(vma))
	185	return ERR_PTR(-EINVAL);
	186
	187	pte = huge_pte_offset(mm, address);
	188
	189	/* hugetlb should be locked, and hence, prefaulted */
	190	WARN_ON(!pte \|\| pte_none(*pte));
	191
	192	page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
	193
25e59881	194	WARN_ON(!PageHead(page));
1da177e4 LT	195
	196	return page;
	197	}
	198
	199	int pmd_huge(pmd_t pmd)
	200	{
	201	return 0;
	202	}
	203
ceb86879 AK	204	int pud_huge(pud_t pud)
	205	{
	206	return 0;
	207	}
	208
1da177e4 LT	209	struct page *
	210	follow_huge_pmd(struct mm_struct *mm, unsigned long address,
	211	pmd_t *pmd, int write)
	212	{
	213	return NULL;
	214	}
	215
	216	#else
	217
	218	struct page *
	219	follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
	220	{
	221	return ERR_PTR(-EINVAL);
	222	}
	223
	224	int pmd_huge(pmd_t pmd)
	225	{
	226	return !!(pmd_val(pmd) & _PAGE_PSE);
	227	}
	228
ceb86879 AK	229	int pud_huge(pud_t pud)
ceb86879 AK	230	{
39c11e6c	231	return !!(pud_val(pud) & _PAGE_PSE);
ceb86879 AK	232	}
ceb86879 AK	233
1da177e4 LT	234	struct page *
	235	follow_huge_pmd(struct mm_struct *mm, unsigned long address,
	236	pmd_t *pmd, int write)
	237	{
	238	struct page *page;
	239
	240	page = pte_page((pte_t )pmd);
	241	if (page)
ceb86879	242	page += ((address & ~PMD_MASK) >> PAGE_SHIFT);
1da177e4 LT	243	return page;
1da177e4 LT	244	}
ceb86879 AK	245
	246	struct page *
	247	follow_huge_pud(struct mm_struct *mm, unsigned long address,
	248	pud_t *pud, int write)
	249	{
	250	struct page *page;
	251
	252	page = pte_page((pte_t )pud);
	253	if (page)
	254	page += ((address & ~PUD_MASK) >> PAGE_SHIFT);
	255	return page;
	256	}
	257
1da177e4 LT	258	#endif
1da177e4 LT	259
1da177e4 LT	260	/* x86_64 also uses this file */
	261
	262	#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
	263	static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
	264	unsigned long addr, unsigned long len,
	265	unsigned long pgoff, unsigned long flags)
	266	{
39c11e6c	267	struct hstate *h = hstate_file(file);
1da177e4 LT	268	struct mm_struct *mm = current->mm;
	269	struct vm_area_struct *vma;
	270	unsigned long start_addr;
	271
1363c3cd WW	272	if (len > mm->cached_hole_size) {
	273	start_addr = mm->free_area_cache;
	274	} else {
	275	start_addr = TASK_UNMAPPED_BASE;
	276	mm->cached_hole_size = 0;
	277	}
1da177e4 LT	278
1da177e4 LT	279	full_search:
39c11e6c	280	addr = ALIGN(start_addr, huge_page_size(h));
1da177e4 LT	281
	282	for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
	283	/* At this point: (!vma \|\| addr < vma->vm_end). */
	284	if (TASK_SIZE - len < addr) {
	285	/*
	286	* Start a new search - just in case we missed
	287	* some holes.
	288	*/
	289	if (start_addr != TASK_UNMAPPED_BASE) {
	290	start_addr = TASK_UNMAPPED_BASE;
1363c3cd	291	mm->cached_hole_size = 0;
1da177e4 LT	292	goto full_search;
	293	}
	294	return -ENOMEM;
	295	}
	296	if (!vma \|\| addr + len <= vma->vm_start) {
	297	mm->free_area_cache = addr + len;
	298	return addr;
	299	}
1363c3cd WW	300	if (addr + mm->cached_hole_size < vma->vm_start)
1363c3cd WW	301	mm->cached_hole_size = vma->vm_start - addr;
39c11e6c	302	addr = ALIGN(vma->vm_end, huge_page_size(h));
1da177e4 LT	303	}
	304	}
	305
	306	static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
	307	unsigned long addr0, unsigned long len,
	308	unsigned long pgoff, unsigned long flags)
	309	{
39c11e6c	310	struct hstate *h = hstate_file(file);
1da177e4 LT	311	struct mm_struct *mm = current->mm;
	312	struct vm_area_struct vma, prev_vma;
	313	unsigned long base = mm->mmap_base, addr = addr0;
1363c3cd	314	unsigned long largest_hole = mm->cached_hole_size;
1da177e4 LT	315	int first_time = 1;
	316
	317	/* don't allow allocations above current base */
	318	if (mm->free_area_cache > base)
	319	mm->free_area_cache = base;
	320
1363c3cd WW	321	if (len <= largest_hole) {
	322	largest_hole = 0;
	323	mm->free_area_cache = base;
	324	}
1da177e4 LT	325	try_again:
	326	/* make sure it can fit in the remaining address space */
	327	if (mm->free_area_cache < len)
	328	goto fail;
	329
	330	/* either no address requested or cant fit in requested address hole */
39c11e6c	331	addr = (mm->free_area_cache - len) & huge_page_mask(h);
1da177e4 LT	332	do {
	333	/*
	334	* Lookup failure means no vma is above this address,
	335	* i.e. return with success:
	336	*/
	337	if (!(vma = find_vma_prev(mm, addr, &prev_vma)))
	338	return addr;
	339
	340	/*
	341	* new region fits between prev_vma->vm_end and
	342	* vma->vm_start, use it:
	343	*/
	344	if (addr + len <= vma->vm_start &&
1363c3cd	345	(!prev_vma \|\| (addr >= prev_vma->vm_end))) {
1da177e4	346	/* remember the address as a hint for next time */
1363c3cd WW	347	mm->cached_hole_size = largest_hole;
	348	return (mm->free_area_cache = addr);
	349	} else {
1da177e4	350	/* pull free_area_cache down to the first hole */
1363c3cd	351	if (mm->free_area_cache == vma->vm_end) {
1da177e4	352	mm->free_area_cache = vma->vm_start;
1363c3cd WW	353	mm->cached_hole_size = largest_hole;
	354	}
	355	}
	356
	357	/* remember the largest hole we saw so far */
	358	if (addr + largest_hole < vma->vm_start)
	359	largest_hole = vma->vm_start - addr;
1da177e4 LT	360
1da177e4 LT	361	/* try just below the current vma->vm_start */
39c11e6c	362	addr = (vma->vm_start - len) & huge_page_mask(h);
1da177e4 LT	363	} while (len <= vma->vm_start);
	364
	365	fail:
	366	/*
	367	* if hint left us with no space for the requested
	368	* mapping then try again:
	369	*/
	370	if (first_time) {
	371	mm->free_area_cache = base;
1363c3cd	372	largest_hole = 0;
1da177e4 LT	373	first_time = 0;
	374	goto try_again;
	375	}
	376	/*
	377	* A failed mmap() very likely causes application failure,
	378	* so fall back to the bottom-up function here. This scenario
	379	* can happen with large stack limits and large mmap()
	380	* allocations.
	381	*/
	382	mm->free_area_cache = TASK_UNMAPPED_BASE;
1363c3cd	383	mm->cached_hole_size = ~0UL;
1da177e4 LT	384	addr = hugetlb_get_unmapped_area_bottomup(file, addr0,
	385	len, pgoff, flags);
	386
	387	/*
	388	* Restore the topdown base:
	389	*/
	390	mm->free_area_cache = base;
1363c3cd	391	mm->cached_hole_size = ~0UL;
1da177e4 LT	392
	393	return addr;
	394	}
	395
	396	unsigned long
	397	hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
	398	unsigned long len, unsigned long pgoff, unsigned long flags)
	399	{
39c11e6c	400	struct hstate *h = hstate_file(file);
1da177e4 LT	401	struct mm_struct *mm = current->mm;
	402	struct vm_area_struct *vma;
	403
39c11e6c	404	if (len & ~huge_page_mask(h))
1da177e4 LT	405	return -EINVAL;
	406	if (len > TASK_SIZE)
	407	return -ENOMEM;
	408
5a8130f2	409	if (flags & MAP_FIXED) {
a5516438	410	if (prepare_hugepage_range(file, addr, len))
5a8130f2 BH	411	return -EINVAL;
	412	return addr;
	413	}
	414
1da177e4	415	if (addr) {
39c11e6c	416	addr = ALIGN(addr, huge_page_size(h));
1da177e4 LT	417	vma = find_vma(mm, addr);
	418	if (TASK_SIZE - len >= addr &&
	419	(!vma \|\| addr + len <= vma->vm_start))
	420	return addr;
	421	}
	422	if (mm->get_unmapped_area == arch_get_unmapped_area)
	423	return hugetlb_get_unmapped_area_bottomup(file, addr, len,
	424	pgoff, flags);
	425	else
	426	return hugetlb_get_unmapped_area_topdown(file, addr, len,
	427	pgoff, flags);
	428	}
	429
	430	#endif /HAVE_ARCH_HUGETLB_UNMAPPED_AREA/
	431
b4718e62 AK	432	#ifdef CONFIG_X86_64
	433	static __init int setup_hugepagesz(char *opt)
	434	{
	435	unsigned long ps = memparse(opt, &opt);
	436	if (ps == PMD_SIZE) {
	437	hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
	438	} else if (ps == PUD_SIZE && cpu_has_gbpages) {
	439	hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
	440	} else {
	441	printk(KERN_ERR "hugepagesz: Unsupported page size %lu M\n",
	442	ps >> 20);
	443	return 0;
	444	}
	445	return 1;
	446	}
	447	__setup("hugepagesz=", setup_hugepagesz);
	448	#endif