[mirror_ubuntu-artful-kernel.git] / arch / i386 / 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/smp_lock.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>

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

	pgd = pgd_offset(mm, addr);
	pud = pud_alloc(mm, pgd, addr);
	if (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))
			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(!PageCompound(page));

	return page;
}

int pmd_huge(pmd_t pmd)
{
	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);
}

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 & ~HPAGE_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 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, HPAGE_SIZE);

	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, HPAGE_SIZE);
	}
}

static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
		unsigned long addr0, unsigned long len,
		unsigned long pgoff, unsigned long flags)
{
	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) & HPAGE_MASK;
	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) & HPAGE_MASK;
	} 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 mm_struct *mm = current->mm;
	struct vm_area_struct *vma;

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

	if (addr) {
		addr = ALIGN(addr, HPAGE_SIZE);
		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*/
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>
	12	#include <linux/smp_lock.h>
	13	#include <linux/slab.h>
	14	#include <linux/err.h>
	15	#include <linux/sysctl.h>
	16	#include <asm/mman.h>
	17	#include <asm/tlb.h>
	18	#include <asm/tlbflush.h>
	19
63551ae0	20	pte_t huge_pte_alloc(struct mm_struct mm, unsigned long addr)
1da177e4 LT	21	{
	22	pgd_t *pgd;
	23	pud_t *pud;
7bf07f3d	24	pte_t *pte = NULL;
1da177e4 LT	25
	26	pgd = pgd_offset(mm, addr);
	27	pud = pud_alloc(mm, pgd, addr);
0e5c9f39 KC	28	if (pud)
	29	pte = (pte_t *) pmd_alloc(mm, pud, addr);
	30	BUG_ON(pte && !pte_none(pte) && !pte_huge(pte));
7bf07f3d	31
7bf07f3d	32	return pte;
1da177e4 LT	33	}
1da177e4 LT	34
63551ae0	35	pte_t huge_pte_offset(struct mm_struct mm, unsigned long addr)
1da177e4 LT	36	{
	37	pgd_t *pgd;
	38	pud_t *pud;
	39	pmd_t *pmd = NULL;
	40
	41	pgd = pgd_offset(mm, addr);
02b0ccef AL	42	if (pgd_present(*pgd)) {
	43	pud = pud_offset(pgd, addr);
	44	if (pud_present(*pud))
	45	pmd = pmd_offset(pud, addr);
	46	}
1da177e4 LT	47	return (pte_t *) pmd;
	48	}
	49
1da177e4 LT	50	#if 0 /* This is just for testing */
	51	struct page *
	52	follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
	53	{
	54	unsigned long start = address;
	55	int length = 1;
	56	int nr;
	57	struct page *page;
	58	struct vm_area_struct *vma;
	59
	60	vma = find_vma(mm, addr);
	61	if (!vma \|\| !is_vm_hugetlb_page(vma))
	62	return ERR_PTR(-EINVAL);
	63
	64	pte = huge_pte_offset(mm, address);
	65
	66	/* hugetlb should be locked, and hence, prefaulted */
	67	WARN_ON(!pte \|\| pte_none(*pte));
	68
	69	page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
	70
	71	WARN_ON(!PageCompound(page));
	72
	73	return page;
	74	}
	75
	76	int pmd_huge(pmd_t pmd)
	77	{
	78	return 0;
	79	}
	80
	81	struct page *
	82	follow_huge_pmd(struct mm_struct *mm, unsigned long address,
	83	pmd_t *pmd, int write)
	84	{
	85	return NULL;
	86	}
	87
	88	#else
	89
	90	struct page *
	91	follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
	92	{
	93	return ERR_PTR(-EINVAL);
	94	}
	95
	96	int pmd_huge(pmd_t pmd)
	97	{
	98	return !!(pmd_val(pmd) & _PAGE_PSE);
	99	}
	100
	101	struct page *
	102	follow_huge_pmd(struct mm_struct *mm, unsigned long address,
	103	pmd_t *pmd, int write)
	104	{
	105	struct page *page;
	106
	107	page = pte_page((pte_t )pmd);
	108	if (page)
	109	page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT);
	110	return page;
	111	}
	112	#endif
	113
1da177e4 LT	114	/* x86_64 also uses this file */
	115
	116	#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
	117	static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
	118	unsigned long addr, unsigned long len,
	119	unsigned long pgoff, unsigned long flags)
	120	{
	121	struct mm_struct *mm = current->mm;
	122	struct vm_area_struct *vma;
	123	unsigned long start_addr;
	124
1363c3cd WW	125	if (len > mm->cached_hole_size) {
	126	start_addr = mm->free_area_cache;
	127	} else {
	128	start_addr = TASK_UNMAPPED_BASE;
	129	mm->cached_hole_size = 0;
	130	}
1da177e4 LT	131
	132	full_search:
	133	addr = ALIGN(start_addr, HPAGE_SIZE);
	134
	135	for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
	136	/* At this point: (!vma \|\| addr < vma->vm_end). */
	137	if (TASK_SIZE - len < addr) {
	138	/*
	139	* Start a new search - just in case we missed
	140	* some holes.
	141	*/
	142	if (start_addr != TASK_UNMAPPED_BASE) {
	143	start_addr = TASK_UNMAPPED_BASE;
1363c3cd	144	mm->cached_hole_size = 0;
1da177e4 LT	145	goto full_search;
	146	}
	147	return -ENOMEM;
	148	}
	149	if (!vma \|\| addr + len <= vma->vm_start) {
	150	mm->free_area_cache = addr + len;
	151	return addr;
	152	}
1363c3cd WW	153	if (addr + mm->cached_hole_size < vma->vm_start)
1363c3cd WW	154	mm->cached_hole_size = vma->vm_start - addr;
1da177e4 LT	155	addr = ALIGN(vma->vm_end, HPAGE_SIZE);
	156	}
	157	}
	158
	159	static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
	160	unsigned long addr0, unsigned long len,
	161	unsigned long pgoff, unsigned long flags)
	162	{
	163	struct mm_struct *mm = current->mm;
	164	struct vm_area_struct vma, prev_vma;
	165	unsigned long base = mm->mmap_base, addr = addr0;
1363c3cd	166	unsigned long largest_hole = mm->cached_hole_size;
1da177e4 LT	167	int first_time = 1;
	168
	169	/* don't allow allocations above current base */
	170	if (mm->free_area_cache > base)
	171	mm->free_area_cache = base;
	172
1363c3cd WW	173	if (len <= largest_hole) {
	174	largest_hole = 0;
	175	mm->free_area_cache = base;
	176	}
1da177e4 LT	177	try_again:
	178	/* make sure it can fit in the remaining address space */
	179	if (mm->free_area_cache < len)
	180	goto fail;
	181
	182	/* either no address requested or cant fit in requested address hole */
	183	addr = (mm->free_area_cache - len) & HPAGE_MASK;
	184	do {
	185	/*
	186	* Lookup failure means no vma is above this address,
	187	* i.e. return with success:
	188	*/
	189	if (!(vma = find_vma_prev(mm, addr, &prev_vma)))
	190	return addr;
	191
	192	/*
	193	* new region fits between prev_vma->vm_end and
	194	* vma->vm_start, use it:
	195	*/
	196	if (addr + len <= vma->vm_start &&
1363c3cd	197	(!prev_vma \|\| (addr >= prev_vma->vm_end))) {
1da177e4	198	/* remember the address as a hint for next time */
1363c3cd WW	199	mm->cached_hole_size = largest_hole;
	200	return (mm->free_area_cache = addr);
	201	} else {
1da177e4	202	/* pull free_area_cache down to the first hole */
1363c3cd	203	if (mm->free_area_cache == vma->vm_end) {
1da177e4	204	mm->free_area_cache = vma->vm_start;
1363c3cd WW	205	mm->cached_hole_size = largest_hole;
	206	}
	207	}
	208
	209	/* remember the largest hole we saw so far */
	210	if (addr + largest_hole < vma->vm_start)
	211	largest_hole = vma->vm_start - addr;
1da177e4 LT	212
	213	/* try just below the current vma->vm_start */
	214	addr = (vma->vm_start - len) & HPAGE_MASK;
	215	} while (len <= vma->vm_start);
	216
	217	fail:
	218	/*
	219	* if hint left us with no space for the requested
	220	* mapping then try again:
	221	*/
	222	if (first_time) {
	223	mm->free_area_cache = base;
1363c3cd	224	largest_hole = 0;
1da177e4 LT	225	first_time = 0;
	226	goto try_again;
	227	}
	228	/*
	229	* A failed mmap() very likely causes application failure,
	230	* so fall back to the bottom-up function here. This scenario
	231	* can happen with large stack limits and large mmap()
	232	* allocations.
	233	*/
	234	mm->free_area_cache = TASK_UNMAPPED_BASE;
1363c3cd	235	mm->cached_hole_size = ~0UL;
1da177e4 LT	236	addr = hugetlb_get_unmapped_area_bottomup(file, addr0,
	237	len, pgoff, flags);
	238
	239	/*
	240	* Restore the topdown base:
	241	*/
	242	mm->free_area_cache = base;
1363c3cd	243	mm->cached_hole_size = ~0UL;
1da177e4 LT	244
	245	return addr;
	246	}
	247
	248	unsigned long
	249	hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
	250	unsigned long len, unsigned long pgoff, unsigned long flags)
	251	{
	252	struct mm_struct *mm = current->mm;
	253	struct vm_area_struct *vma;
	254
	255	if (len & ~HPAGE_MASK)
	256	return -EINVAL;
	257	if (len > TASK_SIZE)
	258	return -ENOMEM;
	259
	260	if (addr) {
	261	addr = ALIGN(addr, HPAGE_SIZE);
	262	vma = find_vma(mm, addr);
	263	if (TASK_SIZE - len >= addr &&
	264	(!vma \|\| addr + len <= vma->vm_start))
	265	return addr;
	266	}
	267	if (mm->get_unmapped_area == arch_get_unmapped_area)
	268	return hugetlb_get_unmapped_area_bottomup(file, addr, len,
	269	pgoff, flags);
	270	else
	271	return hugetlb_get_unmapped_area_topdown(file, addr, len,
	272	pgoff, flags);
	273	}
	274
	275	#endif /HAVE_ARCH_HUGETLB_UNMAPPED_AREA/
	276