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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * SPARC64 Huge TLB page support.
4 *
5 * Copyright (C) 2002, 2003, 2006 David S. Miller (davem@davemloft.net)
6 */
7
8#include <linux/fs.h>
9#include <linux/mm.h>
10#include <linux/sched/mm.h>
11#include <linux/hugetlb.h>
12#include <linux/pagemap.h>
13#include <linux/sysctl.h>
14
15#include <asm/mman.h>
16#include <asm/pgalloc.h>
17#include <asm/pgtable.h>
18#include <asm/tlb.h>
19#include <asm/tlbflush.h>
20#include <asm/cacheflush.h>
21#include <asm/mmu_context.h>
22
23/* Slightly simplified from the non-hugepage variant because by
24 * definition we don't have to worry about any page coloring stuff
25 */
26
27static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *filp,
28 unsigned long addr,
29 unsigned long len,
30 unsigned long pgoff,
31 unsigned long flags)
32{
33 struct hstate *h = hstate_file(filp);
34 unsigned long task_size = TASK_SIZE;
35 struct vm_unmapped_area_info info;
36
37 if (test_thread_flag(TIF_32BIT))
38 task_size = STACK_TOP32;
39
40 info.flags = 0;
41 info.length = len;
42 info.low_limit = TASK_UNMAPPED_BASE;
43 info.high_limit = min(task_size, VA_EXCLUDE_START);
44 info.align_mask = PAGE_MASK & ~huge_page_mask(h);
45 info.align_offset = 0;
46 addr = vm_unmapped_area(&info);
47
48 if ((addr & ~PAGE_MASK) && task_size > VA_EXCLUDE_END) {
49 VM_BUG_ON(addr != -ENOMEM);
50 info.low_limit = VA_EXCLUDE_END;
51 info.high_limit = task_size;
52 addr = vm_unmapped_area(&info);
53 }
54
55 return addr;
56}
57
58static unsigned long
59hugetlb_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
60 const unsigned long len,
61 const unsigned long pgoff,
62 const unsigned long flags)
63{
64 struct hstate *h = hstate_file(filp);
65 struct mm_struct *mm = current->mm;
66 unsigned long addr = addr0;
67 struct vm_unmapped_area_info info;
68
69 /* This should only ever run for 32-bit processes. */
70 BUG_ON(!test_thread_flag(TIF_32BIT));
71
72 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
73 info.length = len;
74 info.low_limit = PAGE_SIZE;
75 info.high_limit = mm->mmap_base;
76 info.align_mask = PAGE_MASK & ~huge_page_mask(h);
77 info.align_offset = 0;
78 addr = vm_unmapped_area(&info);
79
80 /*
81 * A failed mmap() very likely causes application failure,
82 * so fall back to the bottom-up function here. This scenario
83 * can happen with large stack limits and large mmap()
84 * allocations.
85 */
86 if (addr & ~PAGE_MASK) {
87 VM_BUG_ON(addr != -ENOMEM);
88 info.flags = 0;
89 info.low_limit = TASK_UNMAPPED_BASE;
90 info.high_limit = STACK_TOP32;
91 addr = vm_unmapped_area(&info);
92 }
93
94 return addr;
95}
96
97unsigned long
98hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
99 unsigned long len, unsigned long pgoff, unsigned long flags)
100{
101 struct hstate *h = hstate_file(file);
102 struct mm_struct *mm = current->mm;
103 struct vm_area_struct *vma;
104 unsigned long task_size = TASK_SIZE;
105
106 if (test_thread_flag(TIF_32BIT))
107 task_size = STACK_TOP32;
108
109 if (len & ~huge_page_mask(h))
110 return -EINVAL;
111 if (len > task_size)
112 return -ENOMEM;
113
114 if (flags & MAP_FIXED) {
115 if (prepare_hugepage_range(file, addr, len))
116 return -EINVAL;
117 return addr;
118 }
119
120 if (addr) {
121 addr = ALIGN(addr, huge_page_size(h));
122 vma = find_vma(mm, addr);
123 if (task_size - len >= addr &&
124 (!vma || addr + len <= vm_start_gap(vma)))
125 return addr;
126 }
127 if (mm->get_unmapped_area == arch_get_unmapped_area)
128 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
129 pgoff, flags);
130 else
131 return hugetlb_get_unmapped_area_topdown(file, addr, len,
132 pgoff, flags);
133}
134
135static pte_t sun4u_hugepage_shift_to_tte(pte_t entry, unsigned int shift)
136{
137 return entry;
138}
139
140static pte_t sun4v_hugepage_shift_to_tte(pte_t entry, unsigned int shift)
141{
142 unsigned long hugepage_size = _PAGE_SZ4MB_4V;
143
144 pte_val(entry) = pte_val(entry) & ~_PAGE_SZALL_4V;
145
146 switch (shift) {
147 case HPAGE_16GB_SHIFT:
148 hugepage_size = _PAGE_SZ16GB_4V;
149 pte_val(entry) |= _PAGE_PUD_HUGE;
150 break;
151 case HPAGE_2GB_SHIFT:
152 hugepage_size = _PAGE_SZ2GB_4V;
153 pte_val(entry) |= _PAGE_PMD_HUGE;
154 break;
155 case HPAGE_256MB_SHIFT:
156 hugepage_size = _PAGE_SZ256MB_4V;
157 pte_val(entry) |= _PAGE_PMD_HUGE;
158 break;
159 case HPAGE_SHIFT:
160 pte_val(entry) |= _PAGE_PMD_HUGE;
161 break;
162 case HPAGE_64K_SHIFT:
163 hugepage_size = _PAGE_SZ64K_4V;
164 break;
165 default:
166 WARN_ONCE(1, "unsupported hugepage shift=%u\n", shift);
167 }
168
169 pte_val(entry) = pte_val(entry) | hugepage_size;
170 return entry;
171}
172
173static pte_t hugepage_shift_to_tte(pte_t entry, unsigned int shift)
174{
175 if (tlb_type == hypervisor)
176 return sun4v_hugepage_shift_to_tte(entry, shift);
177 else
178 return sun4u_hugepage_shift_to_tte(entry, shift);
179}
180
181pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
182 struct page *page, int writeable)
183{
184 unsigned int shift = huge_page_shift(hstate_vma(vma));
185 pte_t pte;
186
187 pte = hugepage_shift_to_tte(entry, shift);
188
189#ifdef CONFIG_SPARC64
190 /* If this vma has ADI enabled on it, turn on TTE.mcd
191 */
192 if (vma->vm_flags & VM_SPARC_ADI)
193 return pte_mkmcd(pte);
194 else
195 return pte_mknotmcd(pte);
196#else
197 return pte;
198#endif
199}
200
201static unsigned int sun4v_huge_tte_to_shift(pte_t entry)
202{
203 unsigned long tte_szbits = pte_val(entry) & _PAGE_SZALL_4V;
204 unsigned int shift;
205
206 switch (tte_szbits) {
207 case _PAGE_SZ16GB_4V:
208 shift = HPAGE_16GB_SHIFT;
209 break;
210 case _PAGE_SZ2GB_4V:
211 shift = HPAGE_2GB_SHIFT;
212 break;
213 case _PAGE_SZ256MB_4V:
214 shift = HPAGE_256MB_SHIFT;
215 break;
216 case _PAGE_SZ4MB_4V:
217 shift = REAL_HPAGE_SHIFT;
218 break;
219 case _PAGE_SZ64K_4V:
220 shift = HPAGE_64K_SHIFT;
221 break;
222 default:
223 shift = PAGE_SHIFT;
224 break;
225 }
226 return shift;
227}
228
229static unsigned int sun4u_huge_tte_to_shift(pte_t entry)
230{
231 unsigned long tte_szbits = pte_val(entry) & _PAGE_SZALL_4U;
232 unsigned int shift;
233
234 switch (tte_szbits) {
235 case _PAGE_SZ256MB_4U:
236 shift = HPAGE_256MB_SHIFT;
237 break;
238 case _PAGE_SZ4MB_4U:
239 shift = REAL_HPAGE_SHIFT;
240 break;
241 case _PAGE_SZ64K_4U:
242 shift = HPAGE_64K_SHIFT;
243 break;
244 default:
245 shift = PAGE_SHIFT;
246 break;
247 }
248 return shift;
249}
250
251static unsigned int huge_tte_to_shift(pte_t entry)
252{
253 unsigned long shift;
254
255 if (tlb_type == hypervisor)
256 shift = sun4v_huge_tte_to_shift(entry);
257 else
258 shift = sun4u_huge_tte_to_shift(entry);
259
260 if (shift == PAGE_SHIFT)
261 WARN_ONCE(1, "tto_to_shift: invalid hugepage tte=0x%lx\n",
262 pte_val(entry));
263
264 return shift;
265}
266
267static unsigned long huge_tte_to_size(pte_t pte)
268{
269 unsigned long size = 1UL << huge_tte_to_shift(pte);
270
271 if (size == REAL_HPAGE_SIZE)
272 size = HPAGE_SIZE;
273 return size;
274}
275
276pte_t *huge_pte_alloc(struct mm_struct *mm,
277 unsigned long addr, unsigned long sz)
278{
279 pgd_t *pgd;
280 pud_t *pud;
281 pmd_t *pmd;
282
283 pgd = pgd_offset(mm, addr);
284 pud = pud_alloc(mm, pgd, addr);
285 if (!pud)
286 return NULL;
287 if (sz >= PUD_SIZE)
288 return (pte_t *)pud;
289 pmd = pmd_alloc(mm, pud, addr);
290 if (!pmd)
291 return NULL;
292 if (sz >= PMD_SIZE)
293 return (pte_t *)pmd;
294 return pte_alloc_map(mm, pmd, addr);
295}
296
297pte_t *huge_pte_offset(struct mm_struct *mm,
298 unsigned long addr, unsigned long sz)
299{
300 pgd_t *pgd;
301 pud_t *pud;
302 pmd_t *pmd;
303
304 pgd = pgd_offset(mm, addr);
305 if (pgd_none(*pgd))
306 return NULL;
307 pud = pud_offset(pgd, addr);
308 if (pud_none(*pud))
309 return NULL;
310 if (is_hugetlb_pud(*pud))
311 return (pte_t *)pud;
312 pmd = pmd_offset(pud, addr);
313 if (pmd_none(*pmd))
314 return NULL;
315 if (is_hugetlb_pmd(*pmd))
316 return (pte_t *)pmd;
317 return pte_offset_map(pmd, addr);
318}
319
320void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
321 pte_t *ptep, pte_t entry)
322{
323 unsigned int nptes, orig_shift, shift;
324 unsigned long i, size;
325 pte_t orig;
326
327 size = huge_tte_to_size(entry);
328
329 shift = PAGE_SHIFT;
330 if (size >= PUD_SIZE)
331 shift = PUD_SHIFT;
332 else if (size >= PMD_SIZE)
333 shift = PMD_SHIFT;
334 else
335 shift = PAGE_SHIFT;
336
337 nptes = size >> shift;
338
339 if (!pte_present(*ptep) && pte_present(entry))
340 mm->context.hugetlb_pte_count += nptes;
341
342 addr &= ~(size - 1);
343 orig = *ptep;
344 orig_shift = pte_none(orig) ? PAGE_SHIFT : huge_tte_to_shift(orig);
345
346 for (i = 0; i < nptes; i++)
347 ptep[i] = __pte(pte_val(entry) + (i << shift));
348
349 maybe_tlb_batch_add(mm, addr, ptep, orig, 0, orig_shift);
350 /* An HPAGE_SIZE'ed page is composed of two REAL_HPAGE_SIZE'ed pages */
351 if (size == HPAGE_SIZE)
352 maybe_tlb_batch_add(mm, addr + REAL_HPAGE_SIZE, ptep, orig, 0,
353 orig_shift);
354}
355
356pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
357 pte_t *ptep)
358{
359 unsigned int i, nptes, orig_shift, shift;
360 unsigned long size;
361 pte_t entry;
362
363 entry = *ptep;
364 size = huge_tte_to_size(entry);
365
366 shift = PAGE_SHIFT;
367 if (size >= PUD_SIZE)
368 shift = PUD_SHIFT;
369 else if (size >= PMD_SIZE)
370 shift = PMD_SHIFT;
371 else
372 shift = PAGE_SHIFT;
373
374 nptes = size >> shift;
375 orig_shift = pte_none(entry) ? PAGE_SHIFT : huge_tte_to_shift(entry);
376
377 if (pte_present(entry))
378 mm->context.hugetlb_pte_count -= nptes;
379
380 addr &= ~(size - 1);
381 for (i = 0; i < nptes; i++)
382 ptep[i] = __pte(0UL);
383
384 maybe_tlb_batch_add(mm, addr, ptep, entry, 0, orig_shift);
385 /* An HPAGE_SIZE'ed page is composed of two REAL_HPAGE_SIZE'ed pages */
386 if (size == HPAGE_SIZE)
387 maybe_tlb_batch_add(mm, addr + REAL_HPAGE_SIZE, ptep, entry, 0,
388 orig_shift);
389
390 return entry;
391}
392
393int pmd_huge(pmd_t pmd)
394{
395 return !pmd_none(pmd) &&
396 (pmd_val(pmd) & (_PAGE_VALID|_PAGE_PMD_HUGE)) != _PAGE_VALID;
397}
398
399int pud_huge(pud_t pud)
400{
401 return !pud_none(pud) &&
402 (pud_val(pud) & (_PAGE_VALID|_PAGE_PUD_HUGE)) != _PAGE_VALID;
403}
404
405static void hugetlb_free_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
406 unsigned long addr)
407{
408 pgtable_t token = pmd_pgtable(*pmd);
409
410 pmd_clear(pmd);
411 pte_free_tlb(tlb, token, addr);
412 mm_dec_nr_ptes(tlb->mm);
413}
414
415static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
416 unsigned long addr, unsigned long end,
417 unsigned long floor, unsigned long ceiling)
418{
419 pmd_t *pmd;
420 unsigned long next;
421 unsigned long start;
422
423 start = addr;
424 pmd = pmd_offset(pud, addr);
425 do {
426 next = pmd_addr_end(addr, end);
427 if (pmd_none(*pmd))
428 continue;
429 if (is_hugetlb_pmd(*pmd))
430 pmd_clear(pmd);
431 else
432 hugetlb_free_pte_range(tlb, pmd, addr);
433 } while (pmd++, addr = next, addr != end);
434
435 start &= PUD_MASK;
436 if (start < floor)
437 return;
438 if (ceiling) {
439 ceiling &= PUD_MASK;
440 if (!ceiling)
441 return;
442 }
443 if (end - 1 > ceiling - 1)
444 return;
445
446 pmd = pmd_offset(pud, start);
447 pud_clear(pud);
448 pmd_free_tlb(tlb, pmd, start);
449 mm_dec_nr_pmds(tlb->mm);
450}
451
452static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
453 unsigned long addr, unsigned long end,
454 unsigned long floor, unsigned long ceiling)
455{
456 pud_t *pud;
457 unsigned long next;
458 unsigned long start;
459
460 start = addr;
461 pud = pud_offset(pgd, addr);
462 do {
463 next = pud_addr_end(addr, end);
464 if (pud_none_or_clear_bad(pud))
465 continue;
466 if (is_hugetlb_pud(*pud))
467 pud_clear(pud);
468 else
469 hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
470 ceiling);
471 } while (pud++, addr = next, addr != end);
472
473 start &= PGDIR_MASK;
474 if (start < floor)
475 return;
476 if (ceiling) {
477 ceiling &= PGDIR_MASK;
478 if (!ceiling)
479 return;
480 }
481 if (end - 1 > ceiling - 1)
482 return;
483
484 pud = pud_offset(pgd, start);
485 pgd_clear(pgd);
486 pud_free_tlb(tlb, pud, start);
487 mm_dec_nr_puds(tlb->mm);
488}
489
490void hugetlb_free_pgd_range(struct mmu_gather *tlb,
491 unsigned long addr, unsigned long end,
492 unsigned long floor, unsigned long ceiling)
493{
494 pgd_t *pgd;
495 unsigned long next;
496
497 addr &= PMD_MASK;
498 if (addr < floor) {
499 addr += PMD_SIZE;
500 if (!addr)
501 return;
502 }
503 if (ceiling) {
504 ceiling &= PMD_MASK;
505 if (!ceiling)
506 return;
507 }
508 if (end - 1 > ceiling - 1)
509 end -= PMD_SIZE;
510 if (addr > end - 1)
511 return;
512
513 pgd = pgd_offset(tlb->mm, addr);
514 do {
515 next = pgd_addr_end(addr, end);
516 if (pgd_none_or_clear_bad(pgd))
517 continue;
518 hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling);
519 } while (pgd++, addr = next, addr != end);
520}
1/*
2 * SPARC64 Huge TLB page support.
3 *
4 * Copyright (C) 2002, 2003, 2006 David S. Miller (davem@davemloft.net)
5 */
6
7#include <linux/fs.h>
8#include <linux/mm.h>
9#include <linux/hugetlb.h>
10#include <linux/pagemap.h>
11#include <linux/sysctl.h>
12
13#include <asm/mman.h>
14#include <asm/pgalloc.h>
15#include <asm/tlb.h>
16#include <asm/tlbflush.h>
17#include <asm/cacheflush.h>
18#include <asm/mmu_context.h>
19
20/* Slightly simplified from the non-hugepage variant because by
21 * definition we don't have to worry about any page coloring stuff
22 */
23
24static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *filp,
25 unsigned long addr,
26 unsigned long len,
27 unsigned long pgoff,
28 unsigned long flags)
29{
30 unsigned long task_size = TASK_SIZE;
31 struct vm_unmapped_area_info info;
32
33 if (test_thread_flag(TIF_32BIT))
34 task_size = STACK_TOP32;
35
36 info.flags = 0;
37 info.length = len;
38 info.low_limit = TASK_UNMAPPED_BASE;
39 info.high_limit = min(task_size, VA_EXCLUDE_START);
40 info.align_mask = PAGE_MASK & ~HPAGE_MASK;
41 info.align_offset = 0;
42 addr = vm_unmapped_area(&info);
43
44 if ((addr & ~PAGE_MASK) && task_size > VA_EXCLUDE_END) {
45 VM_BUG_ON(addr != -ENOMEM);
46 info.low_limit = VA_EXCLUDE_END;
47 info.high_limit = task_size;
48 addr = vm_unmapped_area(&info);
49 }
50
51 return addr;
52}
53
54static unsigned long
55hugetlb_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
56 const unsigned long len,
57 const unsigned long pgoff,
58 const unsigned long flags)
59{
60 struct mm_struct *mm = current->mm;
61 unsigned long addr = addr0;
62 struct vm_unmapped_area_info info;
63
64 /* This should only ever run for 32-bit processes. */
65 BUG_ON(!test_thread_flag(TIF_32BIT));
66
67 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
68 info.length = len;
69 info.low_limit = PAGE_SIZE;
70 info.high_limit = mm->mmap_base;
71 info.align_mask = PAGE_MASK & ~HPAGE_MASK;
72 info.align_offset = 0;
73 addr = vm_unmapped_area(&info);
74
75 /*
76 * A failed mmap() very likely causes application failure,
77 * so fall back to the bottom-up function here. This scenario
78 * can happen with large stack limits and large mmap()
79 * allocations.
80 */
81 if (addr & ~PAGE_MASK) {
82 VM_BUG_ON(addr != -ENOMEM);
83 info.flags = 0;
84 info.low_limit = TASK_UNMAPPED_BASE;
85 info.high_limit = STACK_TOP32;
86 addr = vm_unmapped_area(&info);
87 }
88
89 return addr;
90}
91
92unsigned long
93hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
94 unsigned long len, unsigned long pgoff, unsigned long flags)
95{
96 struct mm_struct *mm = current->mm;
97 struct vm_area_struct *vma;
98 unsigned long task_size = TASK_SIZE;
99
100 if (test_thread_flag(TIF_32BIT))
101 task_size = STACK_TOP32;
102
103 if (len & ~HPAGE_MASK)
104 return -EINVAL;
105 if (len > task_size)
106 return -ENOMEM;
107
108 if (flags & MAP_FIXED) {
109 if (prepare_hugepage_range(file, addr, len))
110 return -EINVAL;
111 return addr;
112 }
113
114 if (addr) {
115 addr = ALIGN(addr, HPAGE_SIZE);
116 vma = find_vma(mm, addr);
117 if (task_size - len >= addr &&
118 (!vma || addr + len <= vma->vm_start))
119 return addr;
120 }
121 if (mm->get_unmapped_area == arch_get_unmapped_area)
122 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
123 pgoff, flags);
124 else
125 return hugetlb_get_unmapped_area_topdown(file, addr, len,
126 pgoff, flags);
127}
128
129pte_t *huge_pte_alloc(struct mm_struct *mm,
130 unsigned long addr, unsigned long sz)
131{
132 pgd_t *pgd;
133 pud_t *pud;
134 pmd_t *pmd;
135 pte_t *pte = NULL;
136
137 /* We must align the address, because our caller will run
138 * set_huge_pte_at() on whatever we return, which writes out
139 * all of the sub-ptes for the hugepage range. So we have
140 * to give it the first such sub-pte.
141 */
142 addr &= HPAGE_MASK;
143
144 pgd = pgd_offset(mm, addr);
145 pud = pud_alloc(mm, pgd, addr);
146 if (pud) {
147 pmd = pmd_alloc(mm, pud, addr);
148 if (pmd)
149 pte = pte_alloc_map(mm, NULL, pmd, addr);
150 }
151 return pte;
152}
153
154pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
155{
156 pgd_t *pgd;
157 pud_t *pud;
158 pmd_t *pmd;
159 pte_t *pte = NULL;
160
161 addr &= HPAGE_MASK;
162
163 pgd = pgd_offset(mm, addr);
164 if (!pgd_none(*pgd)) {
165 pud = pud_offset(pgd, addr);
166 if (!pud_none(*pud)) {
167 pmd = pmd_offset(pud, addr);
168 if (!pmd_none(*pmd))
169 pte = pte_offset_map(pmd, addr);
170 }
171 }
172 return pte;
173}
174
175int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
176{
177 return 0;
178}
179
180void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
181 pte_t *ptep, pte_t entry)
182{
183 int i;
184
185 if (!pte_present(*ptep) && pte_present(entry))
186 mm->context.huge_pte_count++;
187
188 addr &= HPAGE_MASK;
189 for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
190 set_pte_at(mm, addr, ptep, entry);
191 ptep++;
192 addr += PAGE_SIZE;
193 pte_val(entry) += PAGE_SIZE;
194 }
195}
196
197pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
198 pte_t *ptep)
199{
200 pte_t entry;
201 int i;
202
203 entry = *ptep;
204 if (pte_present(entry))
205 mm->context.huge_pte_count--;
206
207 addr &= HPAGE_MASK;
208
209 for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
210 pte_clear(mm, addr, ptep);
211 addr += PAGE_SIZE;
212 ptep++;
213 }
214
215 return entry;
216}
217
218struct page *follow_huge_addr(struct mm_struct *mm,
219 unsigned long address, int write)
220{
221 return ERR_PTR(-EINVAL);
222}
223
224int pmd_huge(pmd_t pmd)
225{
226 return 0;
227}
228
229int pud_huge(pud_t pud)
230{
231 return 0;
232}
233
234int pmd_huge_support(void)
235{
236 return 0;
237}
238
239struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
240 pmd_t *pmd, int write)
241{
242 return NULL;
243}