/arch/sh64/mm/hugetlbpage.c

  1/*
  2 * arch/sh64/mm/hugetlbpage.c
  3 *
  4 * SuperH HugeTLB page support.
  5 *
  6 * Cloned from sparc64 by Paul Mundt.
  7 *
  8 * Copyright (C) 2002, 2003 David S. Miller (davem@redhat.com)
  9 */
 10
 11#include <linux/config.h>
 12#include <linux/init.h>
 13#include <linux/fs.h>
 14#include <linux/mm.h>
 15#include <linux/hugetlb.h>
 16#include <linux/pagemap.h>
 17#include <linux/smp_lock.h>
 18#include <linux/slab.h>
 19#include <linux/sysctl.h>
 20
 21#include <asm/mman.h>
 22#include <asm/pgalloc.h>
 23#include <asm/tlb.h>
 24#include <asm/tlbflush.h>
 25#include <asm/cacheflush.h>
 26
 27static pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr)
 28{
 29	pgd_t *pgd;
 30	pmd_t *pmd;
 31	pte_t *pte = NULL;
 32
 33	pgd = pgd_offset(mm, addr);
 34	if (pgd) {
 35		pmd = pmd_alloc(mm, pgd, addr);
 36		if (pmd)
 37			pte = pte_alloc_map(mm, pmd, addr);
 38	}
 39	return pte;
 40}
 41
 42static pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
 43{
 44	pgd_t *pgd;
 45	pmd_t *pmd;
 46	pte_t *pte = NULL;
 47
 48	pgd = pgd_offset(mm, addr);
 49	if (pgd) {
 50		pmd = pmd_offset(pgd, addr);
 51		if (pmd)
 52			pte = pte_offset_map(pmd, addr);
 53	}
 54	return pte;
 55}
 56
 57#define mk_pte_huge(entry) do { pte_val(entry) |= _PAGE_SZHUGE; } while (0)
 58
 59static void set_huge_pte(struct mm_struct *mm, struct vm_area_struct *vma,
 60			 struct page *page, pte_t * page_table, int write_access)
 61{
 62	unsigned long i;
 63	pte_t entry;
 64
 65	add_mm_counter(mm, rss, HPAGE_SIZE / PAGE_SIZE);
 66
 67	if (write_access)
 68		entry = pte_mkwrite(pte_mkdirty(mk_pte(page,
 69						       vma->vm_page_prot)));
 70	else
 71		entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));
 72	entry = pte_mkyoung(entry);
 73	mk_pte_huge(entry);
 74
 75	for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
 76		set_pte(page_table, entry);
 77		page_table++;
 78
 79		pte_val(entry) += PAGE_SIZE;
 80	}
 81}
 82
 83/*
 84 * This function checks for proper alignment of input addr and len parameters.
 85 */
 86int is_aligned_hugepage_range(unsigned long addr, unsigned long len)
 87{
 88	if (len & ~HPAGE_MASK)
 89		return -EINVAL;
 90	if (addr & ~HPAGE_MASK)
 91		return -EINVAL;
 92	return 0;
 93}
 94
 95int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
 96			    struct vm_area_struct *vma)
 97{
 98	pte_t *src_pte, *dst_pte, entry;
 99	struct page *ptepage;
100	unsigned long addr = vma->vm_start;
101	unsigned long end = vma->vm_end;
102	int i;
103
104	while (addr < end) {
105		dst_pte = huge_pte_alloc(dst, addr);
106		if (!dst_pte)
107			goto nomem;
108		src_pte = huge_pte_offset(src, addr);
109		BUG_ON(!src_pte || pte_none(*src_pte));
110		entry = *src_pte;
111		ptepage = pte_page(entry);
112		get_page(ptepage);
113		for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
114			set_pte(dst_pte, entry);
115			pte_val(entry) += PAGE_SIZE;
116			dst_pte++;
117		}
118		add_mm_counter(dst, rss, HPAGE_SIZE / PAGE_SIZE);
119		addr += HPAGE_SIZE;
120	}
121	return 0;
122
123nomem:
124	return -ENOMEM;
125}
126
127int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
128			struct page **pages, struct vm_area_struct **vmas,
129			unsigned long *position, int *length, int i)
130{
131	unsigned long vaddr = *position;
132	int remainder = *length;
133
134	WARN_ON(!is_vm_hugetlb_page(vma));
135
136	while (vaddr < vma->vm_end && remainder) {
137		if (pages) {
138			pte_t *pte;
139			struct page *page;
140
141			pte = huge_pte_offset(mm, vaddr);
142
143			/* hugetlb should be locked, and hence, prefaulted */
144			BUG_ON(!pte || pte_none(*pte));
145
146			page = pte_page(*pte);
147
148			WARN_ON(!PageCompound(page));
149
150			get_page(page);
151			pages[i] = page;
152		}
153
154		if (vmas)
155			vmas[i] = vma;
156
157		vaddr += PAGE_SIZE;
158		--remainder;
159		++i;
160	}
161
162	*length = remainder;
163	*position = vaddr;
164
165	return i;
166}
167
168struct page *follow_huge_addr(struct mm_struct *mm,
169			      unsigned long address, int write)
170{
171	return ERR_PTR(-EINVAL);
172}
173
174int pmd_huge(pmd_t pmd)
175{
176	return 0;
177}
178
179struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
180			     pmd_t *pmd, int write)
181{
182	return NULL;
183}
184
185void unmap_hugepage_range(struct vm_area_struct *vma,
186			  unsigned long start, unsigned long end)
187{
188	struct mm_struct *mm = vma->vm_mm;
189	unsigned long address;
190	pte_t *pte;
191	struct page *page;
192	int i;
193
194	BUG_ON(start & (HPAGE_SIZE - 1));
195	BUG_ON(end & (HPAGE_SIZE - 1));
196
197	for (address = start; address < end; address += HPAGE_SIZE) {
198		pte = huge_pte_offset(mm, address);
199		BUG_ON(!pte);
200		if (pte_none(*pte))
201			continue;
202		page = pte_page(*pte);
203		put_page(page);
204		for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
205			pte_clear(mm, address+(i*PAGE_SIZE), pte);
206			pte++;
207		}
208	}
209	add_mm_counter(mm, rss, -((end - start) >> PAGE_SHIFT));
210	flush_tlb_range(vma, start, end);
211}
212
213int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma)
214{
215	struct mm_struct *mm = current->mm;
216	unsigned long addr;
217	int ret = 0;
218
219	BUG_ON(vma->vm_start & ~HPAGE_MASK);
220	BUG_ON(vma->vm_end & ~HPAGE_MASK);
221
222	spin_lock(&mm->page_table_lock);
223	for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
224		unsigned long idx;
225		pte_t *pte = huge_pte_alloc(mm, addr);
226		struct page *page;
227
228		if (!pte) {
229			ret = -ENOMEM;
230			goto out;
231		}
232		if (!pte_none(*pte))
233			continue;
234
235		idx = ((addr - vma->vm_start) >> HPAGE_SHIFT)
236			+ (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
237		page = find_get_page(mapping, idx);
238		if (!page) {
239			/* charge the fs quota first */
240			if (hugetlb_get_quota(mapping)) {
241				ret = -ENOMEM;
242				goto out;
243			}
244			page = alloc_huge_page();
245			if (!page) {
246				hugetlb_put_quota(mapping);
247				ret = -ENOMEM;
248				goto out;
249			}
250			ret = add_to_page_cache(page, mapping, idx, GFP_ATOMIC);
251			if (! ret) {
252				unlock_page(page);
253			} else {
254				hugetlb_put_quota(mapping);
255				free_huge_page(page);
256				goto out;
257			}
258		}
259		set_huge_pte(mm, vma, page, pte, vma->vm_flags & VM_WRITE);
260	}
261out:
262	spin_unlock(&mm->page_table_lock);
263	return ret;
264}