arch/tile/mm/hugetlbpage.c - kernel/mindspeed - Git at Google

 /*
  * Copyright 2010 Tilera Corporation. All Rights Reserved.
  *
  *   This program is free software; you can redistribute it and/or
  *   modify it under the terms of the GNU General Public License
  *   as published by the Free Software Foundation, version 2.
  *
  *   This program is distributed in the hope that it will be useful, but
  *   WITHOUT ANY WARRANTY; without even the implied warranty of
  *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  *   NON INFRINGEMENT.  See the GNU General Public License for
  *   more details.
  *
  * TILE Huge TLB Page Support for Kernel.
  * Taken from i386 hugetlb implementation:
  * 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 <linux/mman.h>
 #include <asm/tlb.h>
 #include <asm/tlbflush.h>

 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;

 	/* We do not yet support multiple huge page sizes. */
 	BUG_ON(sz != PMD_SIZE);

 	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;
 }

 #ifdef HUGETLB_TEST
 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_HUGE_PAGE);
 }

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

 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;
 }

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

 #endif

 #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 can't 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:
 		 */
 		vma = find_vma_prev(mm, addr, &prev_vma);
 		if (!vma) {
 			return addr;
 			break;
 		}

 		/*
 		 * 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;
 			mm->free_area_cache = addr;
 			return 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 (current->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);
 }

 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) {
 		hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 	} else {
 		pr_err("hugepagesz: Unsupported page size %lu M\n",
 			ps >> 20);
 		return 0;
 	}
 	return 1;
 }
 __setup("hugepagesz=", setup_hugepagesz);

 #endif /*HAVE_ARCH_HUGETLB_UNMAPPED_AREA*/
	/*
	* Copyright 2010 Tilera Corporation. All Rights Reserved.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation, version 2.
	*
	* This program is distributed in the hope that it will be useful, but
	* WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
	* NON INFRINGEMENT. See the GNU General Public License for
	* more details.
	*
	* TILE Huge TLB Page Support for Kernel.
	* Taken from i386 hugetlb implementation:
	* 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 <linux/mman.h>
	#include <asm/tlb.h>
	#include <asm/tlbflush.h>

	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;

	/* We do not yet support multiple huge page sizes. */
	BUG_ON(sz != PMD_SIZE);

	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;
	}

	#ifdef HUGETLB_TEST
	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_HUGE_PAGE);
	}

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

	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;
	}

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

	#endif

	#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 can't 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:
	*/
	vma = find_vma_prev(mm, addr, &prev_vma);
	if (!vma) {
	return addr;
	break;
	}

	/*
	* 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;
	mm->free_area_cache = addr;
	return 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 (current->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);
	}

	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) {
	hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
	} else {
	pr_err("hugepagesz: Unsupported page size %lu M\n",
	ps >> 20);
	return 0;
	}
	return 1;
	}
	__setup("hugepagesz=", setup_hugepagesz);

	#endif /HAVE_ARCH_HUGETLB_UNMAPPED_AREA/