a67a9be328135e921ab73e86ed7ce5e34d26d6f0
[linux-2.6.git] / arch / i386 / mm / hugetlbpage.c
1 /*
2  * IA-32 Huge TLB Page Support for Kernel.
3  *
4  * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
5  */
6
7 #include <linux/config.h>
8 #include <linux/init.h>
9 #include <linux/fs.h>
10 #include <linux/mm.h>
11 #include <linux/hugetlb.h>
12 #include <linux/pagemap.h>
13 #include <linux/smp_lock.h>
14 #include <linux/slab.h>
15 #include <linux/err.h>
16 #include <linux/sysctl.h>
17 #include <asm/mman.h>
18 #include <asm/tlb.h>
19 #include <asm/tlbflush.h>
20
21 static pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr)
22 {
23         pgd_t *pgd;
24         pmd_t *pmd = NULL;
25
26         pgd = pgd_offset(mm, addr);
27         pmd = pmd_alloc(mm, pgd, addr);
28         return (pte_t *) pmd;
29 }
30
31 static pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
32 {
33         pgd_t *pgd;
34         pmd_t *pmd = NULL;
35
36         pgd = pgd_offset(mm, addr);
37         pmd = pmd_offset(pgd, addr);
38         return (pte_t *) pmd;
39 }
40
41 static void set_huge_pte(struct mm_struct *mm, struct vm_area_struct *vma, struct page *page, pte_t * page_table, int write_access)
42 {
43         pte_t entry;
44
45         // mm->rss += (HPAGE_SIZE / PAGE_SIZE);
46         vx_rsspages_add(mm, HPAGE_SIZE / PAGE_SIZE);
47         if (write_access) {
48                 entry =
49                     pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
50         } else
51                 entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));
52         entry = pte_mkyoung(entry);
53         mk_pte_huge(entry);
54         set_pte(page_table, entry);
55 }
56
57 /*
58  * This function checks for proper alignment of input addr and len parameters.
59  */
60 int is_aligned_hugepage_range(unsigned long addr, unsigned long len)
61 {
62         if (len & ~HPAGE_MASK)
63                 return -EINVAL;
64         if (addr & ~HPAGE_MASK)
65                 return -EINVAL;
66         return 0;
67 }
68
69 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
70                         struct vm_area_struct *vma)
71 {
72         pte_t *src_pte, *dst_pte, entry;
73         struct page *ptepage;
74         unsigned long addr = vma->vm_start;
75         unsigned long end = vma->vm_end;
76
77         while (addr < end) {
78                 dst_pte = huge_pte_alloc(dst, addr);
79                 if (!dst_pte)
80                         goto nomem;
81                 src_pte = huge_pte_offset(src, addr);
82                 entry = *src_pte;
83                 ptepage = pte_page(entry);
84                 get_page(ptepage);
85                 set_pte(dst_pte, entry);
86                 // dst->rss += (HPAGE_SIZE / PAGE_SIZE);
87                 vx_rsspages_add(dst, HPAGE_SIZE / PAGE_SIZE);
88                 addr += HPAGE_SIZE;
89         }
90         return 0;
91
92 nomem:
93         return -ENOMEM;
94 }
95
96 int
97 follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
98                     struct page **pages, struct vm_area_struct **vmas,
99                     unsigned long *position, int *length, int i)
100 {
101         unsigned long vpfn, vaddr = *position;
102         int remainder = *length;
103
104         WARN_ON(!is_vm_hugetlb_page(vma));
105
106         vpfn = vaddr/PAGE_SIZE;
107         while (vaddr < vma->vm_end && remainder) {
108
109                 if (pages) {
110                         pte_t *pte;
111                         struct page *page;
112
113                         pte = huge_pte_offset(mm, vaddr);
114
115                         /* hugetlb should be locked, and hence, prefaulted */
116                         WARN_ON(!pte || pte_none(*pte));
117
118                         page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
119
120                         WARN_ON(!PageCompound(page));
121
122                         get_page(page);
123                         pages[i] = page;
124                 }
125
126                 if (vmas)
127                         vmas[i] = vma;
128
129                 vaddr += PAGE_SIZE;
130                 ++vpfn;
131                 --remainder;
132                 ++i;
133         }
134
135         *length = remainder;
136         *position = vaddr;
137
138         return i;
139 }
140
141 #if 0   /* This is just for testing */
142 struct page *
143 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
144 {
145         unsigned long start = address;
146         int length = 1;
147         int nr;
148         struct page *page;
149         struct vm_area_struct *vma;
150
151         if (! mm->used_hugetlb)
152                 return ERR_PTR(-EINVAL);
153
154         vma = find_vma(mm, addr);
155         if (!vma || !is_vm_hugetlb_page(vma))
156                 return ERR_PTR(-EINVAL);
157
158         pte = huge_pte_offset(mm, address);
159
160         /* hugetlb should be locked, and hence, prefaulted */
161         WARN_ON(!pte || pte_none(*pte));
162
163         page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
164
165         WARN_ON(!PageCompound(page));
166
167         return page;
168 }
169
170 int pmd_huge(pmd_t pmd)
171 {
172         return 0;
173 }
174
175 struct page *
176 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
177                 pmd_t *pmd, int write)
178 {
179         return NULL;
180 }
181
182 #else
183
184 struct page *
185 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
186 {
187         return ERR_PTR(-EINVAL);
188 }
189
190 int pmd_huge(pmd_t pmd)
191 {
192         return !!(pmd_val(pmd) & _PAGE_PSE);
193 }
194
195 struct page *
196 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
197                 pmd_t *pmd, int write)
198 {
199         struct page *page;
200
201         page = pte_page(*(pte_t *)pmd);
202         if (page)
203                 page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT);
204         return page;
205 }
206 #endif
207
208 void unmap_hugepage_range(struct vm_area_struct *vma,
209                 unsigned long start, unsigned long end)
210 {
211         struct mm_struct *mm = vma->vm_mm;
212         unsigned long address;
213         pte_t pte;
214         struct page *page;
215
216         BUG_ON(start & (HPAGE_SIZE - 1));
217         BUG_ON(end & (HPAGE_SIZE - 1));
218
219         for (address = start; address < end; address += HPAGE_SIZE) {
220                 pte = ptep_get_and_clear(huge_pte_offset(mm, address));
221                 if (pte_none(pte))
222                         continue;
223                 page = pte_page(pte);
224                 put_page(page);
225         }
226         // mm->rss -= (end - start) >> PAGE_SHIFT;
227         vx_rsspages_sub(mm, (end - start) >> PAGE_SHIFT);
228         flush_tlb_range(vma, start, end);
229 }
230
231 int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma)
232 {
233         struct mm_struct *mm = current->mm;
234         unsigned long addr;
235         int ret = 0;
236
237         BUG_ON(vma->vm_start & ~HPAGE_MASK);
238         BUG_ON(vma->vm_end & ~HPAGE_MASK);
239
240         spin_lock(&mm->page_table_lock);
241         for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
242                 unsigned long idx;
243                 pte_t *pte = huge_pte_alloc(mm, addr);
244                 struct page *page;
245
246                 if (!pte) {
247                         ret = -ENOMEM;
248                         goto out;
249                 }
250
251                 if (!pte_none(*pte)) {
252                         pmd_t *pmd = (pmd_t *) pte;
253
254                         page = pmd_page(*pmd);
255                         pmd_clear(pmd);
256                         dec_page_state(nr_page_table_pages);
257                         page_cache_release(page);
258                 }
259
260                 idx = ((addr - vma->vm_start) >> HPAGE_SHIFT)
261                         + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
262                 page = find_get_page(mapping, idx);
263                 if (!page) {
264                         /* charge the fs quota first */
265                         if (hugetlb_get_quota(mapping)) {
266                                 ret = -ENOMEM;
267                                 goto out;
268                         }
269                         page = alloc_huge_page();
270                         if (!page) {
271                                 hugetlb_put_quota(mapping);
272                                 ret = -ENOMEM;
273                                 goto out;
274                         }
275                         ret = add_to_page_cache(page, mapping, idx, GFP_ATOMIC);
276                         if (! ret) {
277                                 unlock_page(page);
278                         } else {
279                                 hugetlb_put_quota(mapping);
280                                 free_huge_page(page);
281                                 goto out;
282                         }
283                 }
284                 set_huge_pte(mm, vma, page, pte, vma->vm_flags & VM_WRITE);
285         }
286 out:
287         spin_unlock(&mm->page_table_lock);
288         return ret;
289 }