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1/*
2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation, version 2.
7 *
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
11 * NON INFRINGEMENT. See the GNU General Public License for
12 * more details.
13 *
14 * TILE Huge TLB Page Support for Kernel.
15 * Taken from i386 hugetlb implementation:
16 * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
17 */
18
19#include <linux/init.h>
20#include <linux/fs.h>
21#include <linux/mm.h>
22#include <linux/hugetlb.h>
23#include <linux/pagemap.h>
24#include <linux/slab.h>
25#include <linux/err.h>
26#include <linux/sysctl.h>
27#include <linux/mman.h>
28#include <asm/tlb.h>
29#include <asm/tlbflush.h>
30#include <asm/setup.h>
31
32#ifdef CONFIG_HUGETLB_SUPER_PAGES
33
34/*
35 * Provide an additional huge page size (in addition to the regular default
36 * huge page size) if no "hugepagesz" arguments are specified.
37 * Note that it must be smaller than the default huge page size so
38 * that it's possible to allocate them on demand from the buddy allocator.
39 * You can change this to 64K (on a 16K build), 256K, 1M, or 4M,
40 * or not define it at all.
41 */
42#define ADDITIONAL_HUGE_SIZE (1024 * 1024UL)
43
44/* "Extra" page-size multipliers, one per level of the page table. */
45int huge_shift[HUGE_SHIFT_ENTRIES] = {
46#ifdef ADDITIONAL_HUGE_SIZE
47#define ADDITIONAL_HUGE_SHIFT __builtin_ctzl(ADDITIONAL_HUGE_SIZE / PAGE_SIZE)
48 [HUGE_SHIFT_PAGE] = ADDITIONAL_HUGE_SHIFT
49#endif
50};
51
52/*
53 * This routine is a hybrid of pte_alloc_map() and pte_alloc_kernel().
54 * It assumes that L2 PTEs are never in HIGHMEM (we don't support that).
55 * It locks the user pagetable, and bumps up the mm->nr_ptes field,
56 * but otherwise allocate the page table using the kernel versions.
57 */
58static pte_t *pte_alloc_hugetlb(struct mm_struct *mm, pmd_t *pmd,
59 unsigned long address)
60{
61 pte_t *new;
62
63 if (pmd_none(*pmd)) {
64 new = pte_alloc_one_kernel(mm, address);
65 if (!new)
66 return NULL;
67
68 smp_wmb(); /* See comment in __pte_alloc */
69
70 spin_lock(&mm->page_table_lock);
71 if (likely(pmd_none(*pmd))) { /* Has another populated it ? */
72 mm->nr_ptes++;
73 pmd_populate_kernel(mm, pmd, new);
74 new = NULL;
75 } else
76 VM_BUG_ON(pmd_trans_splitting(*pmd));
77 spin_unlock(&mm->page_table_lock);
78 if (new)
79 pte_free_kernel(mm, new);
80 }
81
82 return pte_offset_kernel(pmd, address);
83}
84#endif
85
86pte_t *huge_pte_alloc(struct mm_struct *mm,
87 unsigned long addr, unsigned long sz)
88{
89 pgd_t *pgd;
90 pud_t *pud;
91
92 addr &= -sz; /* Mask off any low bits in the address. */
93
94 pgd = pgd_offset(mm, addr);
95 pud = pud_alloc(mm, pgd, addr);
96
97#ifdef CONFIG_HUGETLB_SUPER_PAGES
98 if (sz >= PGDIR_SIZE) {
99 BUG_ON(sz != PGDIR_SIZE &&
100 sz != PGDIR_SIZE << huge_shift[HUGE_SHIFT_PGDIR]);
101 return (pte_t *)pud;
102 } else {
103 pmd_t *pmd = pmd_alloc(mm, pud, addr);
104 if (sz >= PMD_SIZE) {
105 BUG_ON(sz != PMD_SIZE &&
106 sz != (PMD_SIZE << huge_shift[HUGE_SHIFT_PMD]));
107 return (pte_t *)pmd;
108 }
109 else {
110 if (sz != PAGE_SIZE << huge_shift[HUGE_SHIFT_PAGE])
111 panic("Unexpected page size %#lx\n", sz);
112 return pte_alloc_hugetlb(mm, pmd, addr);
113 }
114 }
115#else
116 BUG_ON(sz != PMD_SIZE);
117 return (pte_t *) pmd_alloc(mm, pud, addr);
118#endif
119}
120
121static pte_t *get_pte(pte_t *base, int index, int level)
122{
123 pte_t *ptep = base + index;
124#ifdef CONFIG_HUGETLB_SUPER_PAGES
125 if (!pte_present(*ptep) && huge_shift[level] != 0) {
126 unsigned long mask = -1UL << huge_shift[level];
127 pte_t *super_ptep = base + (index & mask);
128 pte_t pte = *super_ptep;
129 if (pte_present(pte) && pte_super(pte))
130 ptep = super_ptep;
131 }
132#endif
133 return ptep;
134}
135
136pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
137{
138 pgd_t *pgd;
139 pud_t *pud;
140 pmd_t *pmd;
141#ifdef CONFIG_HUGETLB_SUPER_PAGES
142 pte_t *pte;
143#endif
144
145 /* Get the top-level page table entry. */
146 pgd = (pgd_t *)get_pte((pte_t *)mm->pgd, pgd_index(addr), 0);
147 if (!pgd_present(*pgd))
148 return NULL;
149
150 /* We don't have four levels. */
151 pud = pud_offset(pgd, addr);
152#ifndef __PAGETABLE_PUD_FOLDED
153# error support fourth page table level
154#endif
155
156 /* Check for an L0 huge PTE, if we have three levels. */
157#ifndef __PAGETABLE_PMD_FOLDED
158 if (pud_huge(*pud))
159 return (pte_t *)pud;
160
161 pmd = (pmd_t *)get_pte((pte_t *)pud_page_vaddr(*pud),
162 pmd_index(addr), 1);
163 if (!pmd_present(*pmd))
164 return NULL;
165#else
166 pmd = pmd_offset(pud, addr);
167#endif
168
169 /* Check for an L1 huge PTE. */
170 if (pmd_huge(*pmd))
171 return (pte_t *)pmd;
172
173#ifdef CONFIG_HUGETLB_SUPER_PAGES
174 /* Check for an L2 huge PTE. */
175 pte = get_pte((pte_t *)pmd_page_vaddr(*pmd), pte_index(addr), 2);
176 if (!pte_present(*pte))
177 return NULL;
178 if (pte_super(*pte))
179 return pte;
180#endif
181
182 return NULL;
183}
184
185struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address,
186 int write)
187{
188 return ERR_PTR(-EINVAL);
189}
190
191int pmd_huge(pmd_t pmd)
192{
193 return !!(pmd_val(pmd) & _PAGE_HUGE_PAGE);
194}
195
196int pud_huge(pud_t pud)
197{
198 return !!(pud_val(pud) & _PAGE_HUGE_PAGE);
199}
200
201struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
202 pmd_t *pmd, int write)
203{
204 struct page *page;
205
206 page = pte_page(*(pte_t *)pmd);
207 if (page)
208 page += ((address & ~PMD_MASK) >> PAGE_SHIFT);
209 return page;
210}
211
212struct page *follow_huge_pud(struct mm_struct *mm, unsigned long address,
213 pud_t *pud, int write)
214{
215 struct page *page;
216
217 page = pte_page(*(pte_t *)pud);
218 if (page)
219 page += ((address & ~PUD_MASK) >> PAGE_SHIFT);
220 return page;
221}
222
223int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
224{
225 return 0;
226}
227
228#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
229static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
230 unsigned long addr, unsigned long len,
231 unsigned long pgoff, unsigned long flags)
232{
233 struct hstate *h = hstate_file(file);
234 struct mm_struct *mm = current->mm;
235 struct vm_area_struct *vma;
236 unsigned long start_addr;
237
238 if (len > mm->cached_hole_size) {
239 start_addr = mm->free_area_cache;
240 } else {
241 start_addr = TASK_UNMAPPED_BASE;
242 mm->cached_hole_size = 0;
243 }
244
245full_search:
246 addr = ALIGN(start_addr, huge_page_size(h));
247
248 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
249 /* At this point: (!vma || addr < vma->vm_end). */
250 if (TASK_SIZE - len < addr) {
251 /*
252 * Start a new search - just in case we missed
253 * some holes.
254 */
255 if (start_addr != TASK_UNMAPPED_BASE) {
256 start_addr = TASK_UNMAPPED_BASE;
257 mm->cached_hole_size = 0;
258 goto full_search;
259 }
260 return -ENOMEM;
261 }
262 if (!vma || addr + len <= vma->vm_start) {
263 mm->free_area_cache = addr + len;
264 return addr;
265 }
266 if (addr + mm->cached_hole_size < vma->vm_start)
267 mm->cached_hole_size = vma->vm_start - addr;
268 addr = ALIGN(vma->vm_end, huge_page_size(h));
269 }
270}
271
272static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
273 unsigned long addr0, unsigned long len,
274 unsigned long pgoff, unsigned long flags)
275{
276 struct hstate *h = hstate_file(file);
277 struct mm_struct *mm = current->mm;
278 struct vm_area_struct *vma, *prev_vma;
279 unsigned long base = mm->mmap_base, addr = addr0;
280 unsigned long largest_hole = mm->cached_hole_size;
281 int first_time = 1;
282
283 /* don't allow allocations above current base */
284 if (mm->free_area_cache > base)
285 mm->free_area_cache = base;
286
287 if (len <= largest_hole) {
288 largest_hole = 0;
289 mm->free_area_cache = base;
290 }
291try_again:
292 /* make sure it can fit in the remaining address space */
293 if (mm->free_area_cache < len)
294 goto fail;
295
296 /* either no address requested or can't fit in requested address hole */
297 addr = (mm->free_area_cache - len) & huge_page_mask(h);
298 do {
299 /*
300 * Lookup failure means no vma is above this address,
301 * i.e. return with success:
302 */
303 vma = find_vma_prev(mm, addr, &prev_vma);
304 if (!vma) {
305 return addr;
306 break;
307 }
308
309 /*
310 * new region fits between prev_vma->vm_end and
311 * vma->vm_start, use it:
312 */
313 if (addr + len <= vma->vm_start &&
314 (!prev_vma || (addr >= prev_vma->vm_end))) {
315 /* remember the address as a hint for next time */
316 mm->cached_hole_size = largest_hole;
317 mm->free_area_cache = addr;
318 return addr;
319 } else {
320 /* pull free_area_cache down to the first hole */
321 if (mm->free_area_cache == vma->vm_end) {
322 mm->free_area_cache = vma->vm_start;
323 mm->cached_hole_size = largest_hole;
324 }
325 }
326
327 /* remember the largest hole we saw so far */
328 if (addr + largest_hole < vma->vm_start)
329 largest_hole = vma->vm_start - addr;
330
331 /* try just below the current vma->vm_start */
332 addr = (vma->vm_start - len) & huge_page_mask(h);
333
334 } while (len <= vma->vm_start);
335
336fail:
337 /*
338 * if hint left us with no space for the requested
339 * mapping then try again:
340 */
341 if (first_time) {
342 mm->free_area_cache = base;
343 largest_hole = 0;
344 first_time = 0;
345 goto try_again;
346 }
347 /*
348 * A failed mmap() very likely causes application failure,
349 * so fall back to the bottom-up function here. This scenario
350 * can happen with large stack limits and large mmap()
351 * allocations.
352 */
353 mm->free_area_cache = TASK_UNMAPPED_BASE;
354 mm->cached_hole_size = ~0UL;
355 addr = hugetlb_get_unmapped_area_bottomup(file, addr0,
356 len, pgoff, flags);
357
358 /*
359 * Restore the topdown base:
360 */
361 mm->free_area_cache = base;
362 mm->cached_hole_size = ~0UL;
363
364 return addr;
365}
366
367unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
368 unsigned long len, unsigned long pgoff, unsigned long flags)
369{
370 struct hstate *h = hstate_file(file);
371 struct mm_struct *mm = current->mm;
372 struct vm_area_struct *vma;
373
374 if (len & ~huge_page_mask(h))
375 return -EINVAL;
376 if (len > TASK_SIZE)
377 return -ENOMEM;
378
379 if (flags & MAP_FIXED) {
380 if (prepare_hugepage_range(file, addr, len))
381 return -EINVAL;
382 return addr;
383 }
384
385 if (addr) {
386 addr = ALIGN(addr, huge_page_size(h));
387 vma = find_vma(mm, addr);
388 if (TASK_SIZE - len >= addr &&
389 (!vma || addr + len <= vma->vm_start))
390 return addr;
391 }
392 if (current->mm->get_unmapped_area == arch_get_unmapped_area)
393 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
394 pgoff, flags);
395 else
396 return hugetlb_get_unmapped_area_topdown(file, addr, len,
397 pgoff, flags);
398}
399#endif /* HAVE_ARCH_HUGETLB_UNMAPPED_AREA */
400
401#ifdef CONFIG_HUGETLB_SUPER_PAGES
402static __init int __setup_hugepagesz(unsigned long ps)
403{
404 int log_ps = __builtin_ctzl(ps);
405 int level, base_shift;
406
407 if ((1UL << log_ps) != ps || (log_ps & 1) != 0) {
408 pr_warn("Not enabling %ld byte huge pages;"
409 " must be a power of four.\n", ps);
410 return -EINVAL;
411 }
412
413 if (ps > 64*1024*1024*1024UL) {
414 pr_warn("Not enabling %ld MB huge pages;"
415 " largest legal value is 64 GB .\n", ps >> 20);
416 return -EINVAL;
417 } else if (ps >= PUD_SIZE) {
418 static long hv_jpage_size;
419 if (hv_jpage_size == 0)
420 hv_jpage_size = hv_sysconf(HV_SYSCONF_PAGE_SIZE_JUMBO);
421 if (hv_jpage_size != PUD_SIZE) {
422 pr_warn("Not enabling >= %ld MB huge pages:"
423 " hypervisor reports size %ld\n",
424 PUD_SIZE >> 20, hv_jpage_size);
425 return -EINVAL;
426 }
427 level = 0;
428 base_shift = PUD_SHIFT;
429 } else if (ps >= PMD_SIZE) {
430 level = 1;
431 base_shift = PMD_SHIFT;
432 } else if (ps > PAGE_SIZE) {
433 level = 2;
434 base_shift = PAGE_SHIFT;
435 } else {
436 pr_err("hugepagesz: huge page size %ld too small\n", ps);
437 return -EINVAL;
438 }
439
440 if (log_ps != base_shift) {
441 int shift_val = log_ps - base_shift;
442 if (huge_shift[level] != 0) {
443 int old_shift = base_shift + huge_shift[level];
444 pr_warn("Not enabling %ld MB huge pages;"
445 " already have size %ld MB.\n",
446 ps >> 20, (1UL << old_shift) >> 20);
447 return -EINVAL;
448 }
449 if (hv_set_pte_super_shift(level, shift_val) != 0) {
450 pr_warn("Not enabling %ld MB huge pages;"
451 " no hypervisor support.\n", ps >> 20);
452 return -EINVAL;
453 }
454 printk(KERN_DEBUG "Enabled %ld MB huge pages\n", ps >> 20);
455 huge_shift[level] = shift_val;
456 }
457
458 hugetlb_add_hstate(log_ps - PAGE_SHIFT);
459
460 return 0;
461}
462
463static bool saw_hugepagesz;
464
465static __init int setup_hugepagesz(char *opt)
466{
467 if (!saw_hugepagesz) {
468 saw_hugepagesz = true;
469 memset(huge_shift, 0, sizeof(huge_shift));
470 }
471 return __setup_hugepagesz(memparse(opt, NULL));
472}
473__setup("hugepagesz=", setup_hugepagesz);
474
475#ifdef ADDITIONAL_HUGE_SIZE
476/*
477 * Provide an additional huge page size if no "hugepagesz" args are given.
478 * In that case, all the cores have properly set up their hv super_shift
479 * already, but we need to notify the hugetlb code to enable the
480 * new huge page size from the Linux point of view.
481 */
482static __init int add_default_hugepagesz(void)
483{
484 if (!saw_hugepagesz) {
485 BUILD_BUG_ON(ADDITIONAL_HUGE_SIZE >= PMD_SIZE ||
486 ADDITIONAL_HUGE_SIZE <= PAGE_SIZE);
487 BUILD_BUG_ON((PAGE_SIZE << ADDITIONAL_HUGE_SHIFT) !=
488 ADDITIONAL_HUGE_SIZE);
489 BUILD_BUG_ON(ADDITIONAL_HUGE_SHIFT & 1);
490 hugetlb_add_hstate(ADDITIONAL_HUGE_SHIFT);
491 }
492 return 0;
493}
494arch_initcall(add_default_hugepagesz);
495#endif
496
497#endif /* CONFIG_HUGETLB_SUPER_PAGES */