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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * IA-32 Huge TLB Page Support for Kernel.
4 *
5 * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
6 */
7
8#include <linux/init.h>
9#include <linux/fs.h>
10#include <linux/mm.h>
11#include <linux/sched/mm.h>
12#include <linux/hugetlb.h>
13#include <linux/pagemap.h>
14#include <linux/err.h>
15#include <linux/sysctl.h>
16#include <linux/compat.h>
17#include <asm/mman.h>
18#include <asm/tlb.h>
19#include <asm/tlbflush.h>
20#include <asm/elf.h>
21
22/*
23 * pmd_huge() returns 1 if @pmd is hugetlb related entry, that is normal
24 * hugetlb entry or non-present (migration or hwpoisoned) hugetlb entry.
25 * Otherwise, returns 0.
26 */
27int pmd_huge(pmd_t pmd)
28{
29 return !pmd_none(pmd) &&
30 (pmd_val(pmd) & (_PAGE_PRESENT|_PAGE_PSE)) != _PAGE_PRESENT;
31}
32
33/*
34 * pud_huge() returns 1 if @pud is hugetlb related entry, that is normal
35 * hugetlb entry or non-present (migration or hwpoisoned) hugetlb entry.
36 * Otherwise, returns 0.
37 */
38int pud_huge(pud_t pud)
39{
40#if CONFIG_PGTABLE_LEVELS > 2
41 return !pud_none(pud) &&
42 (pud_val(pud) & (_PAGE_PRESENT|_PAGE_PSE)) != _PAGE_PRESENT;
43#else
44 return 0;
45#endif
46}
47
48#ifdef CONFIG_HUGETLB_PAGE
49static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
50 unsigned long addr, unsigned long len,
51 unsigned long pgoff, unsigned long flags)
52{
53 struct hstate *h = hstate_file(file);
54 struct vm_unmapped_area_info info;
55
56 info.flags = 0;
57 info.length = len;
58 info.low_limit = get_mmap_base(1);
59
60 /*
61 * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
62 * in the full address space.
63 */
64 info.high_limit = in_32bit_syscall() ?
65 task_size_32bit() : task_size_64bit(addr > DEFAULT_MAP_WINDOW);
66
67 info.align_mask = PAGE_MASK & ~huge_page_mask(h);
68 info.align_offset = 0;
69 return vm_unmapped_area(&info);
70}
71
72static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
73 unsigned long addr, unsigned long len,
74 unsigned long pgoff, unsigned long flags)
75{
76 struct hstate *h = hstate_file(file);
77 struct vm_unmapped_area_info info;
78
79 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
80 info.length = len;
81 info.low_limit = PAGE_SIZE;
82 info.high_limit = get_mmap_base(0);
83
84 /*
85 * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
86 * in the full address space.
87 */
88 if (addr > DEFAULT_MAP_WINDOW && !in_32bit_syscall())
89 info.high_limit += TASK_SIZE_MAX - DEFAULT_MAP_WINDOW;
90
91 info.align_mask = PAGE_MASK & ~huge_page_mask(h);
92 info.align_offset = 0;
93 addr = vm_unmapped_area(&info);
94
95 /*
96 * A failed mmap() very likely causes application failure,
97 * so fall back to the bottom-up function here. This scenario
98 * can happen with large stack limits and large mmap()
99 * allocations.
100 */
101 if (addr & ~PAGE_MASK) {
102 VM_BUG_ON(addr != -ENOMEM);
103 info.flags = 0;
104 info.low_limit = TASK_UNMAPPED_BASE;
105 info.high_limit = TASK_SIZE_LOW;
106 addr = vm_unmapped_area(&info);
107 }
108
109 return addr;
110}
111
112unsigned long
113hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
114 unsigned long len, unsigned long pgoff, unsigned long flags)
115{
116 struct hstate *h = hstate_file(file);
117 struct mm_struct *mm = current->mm;
118 struct vm_area_struct *vma;
119
120 if (len & ~huge_page_mask(h))
121 return -EINVAL;
122
123 if (len > TASK_SIZE)
124 return -ENOMEM;
125
126 /* No address checking. See comment at mmap_address_hint_valid() */
127 if (flags & MAP_FIXED) {
128 if (prepare_hugepage_range(file, addr, len))
129 return -EINVAL;
130 return addr;
131 }
132
133 if (addr) {
134 addr &= huge_page_mask(h);
135 if (!mmap_address_hint_valid(addr, len))
136 goto get_unmapped_area;
137
138 vma = find_vma(mm, addr);
139 if (!vma || addr + len <= vm_start_gap(vma))
140 return addr;
141 }
142
143get_unmapped_area:
144 if (mm->get_unmapped_area == arch_get_unmapped_area)
145 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
146 pgoff, flags);
147 else
148 return hugetlb_get_unmapped_area_topdown(file, addr, len,
149 pgoff, flags);
150}
151#endif /* CONFIG_HUGETLB_PAGE */
152
153#ifdef CONFIG_X86_64
154bool __init arch_hugetlb_valid_size(unsigned long size)
155{
156 if (size == PMD_SIZE)
157 return true;
158 else if (size == PUD_SIZE && boot_cpu_has(X86_FEATURE_GBPAGES))
159 return true;
160 else
161 return false;
162}
163
164#ifdef CONFIG_CONTIG_ALLOC
165static __init int gigantic_pages_init(void)
166{
167 /* With compaction or CMA we can allocate gigantic pages at runtime */
168 if (boot_cpu_has(X86_FEATURE_GBPAGES))
169 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
170 return 0;
171}
172arch_initcall(gigantic_pages_init);
173#endif
174#endif
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/init.h>
8#include <linux/fs.h>
9#include <linux/mm.h>
10#include <linux/hugetlb.h>
11#include <linux/pagemap.h>
12#include <linux/err.h>
13#include <linux/sysctl.h>
14#include <asm/mman.h>
15#include <asm/tlb.h>
16#include <asm/tlbflush.h>
17#include <asm/pgalloc.h>
18
19static unsigned long page_table_shareable(struct vm_area_struct *svma,
20 struct vm_area_struct *vma,
21 unsigned long addr, pgoff_t idx)
22{
23 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
24 svma->vm_start;
25 unsigned long sbase = saddr & PUD_MASK;
26 unsigned long s_end = sbase + PUD_SIZE;
27
28 /* Allow segments to share if only one is marked locked */
29 unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED;
30 unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED;
31
32 /*
33 * match the virtual addresses, permission and the alignment of the
34 * page table page.
35 */
36 if (pmd_index(addr) != pmd_index(saddr) ||
37 vm_flags != svm_flags ||
38 sbase < svma->vm_start || svma->vm_end < s_end)
39 return 0;
40
41 return saddr;
42}
43
44static int vma_shareable(struct vm_area_struct *vma, unsigned long addr)
45{
46 unsigned long base = addr & PUD_MASK;
47 unsigned long end = base + PUD_SIZE;
48
49 /*
50 * check on proper vm_flags and page table alignment
51 */
52 if (vma->vm_flags & VM_MAYSHARE &&
53 vma->vm_start <= base && end <= vma->vm_end)
54 return 1;
55 return 0;
56}
57
58/*
59 * search for a shareable pmd page for hugetlb.
60 */
61static void huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
62{
63 struct vm_area_struct *vma = find_vma(mm, addr);
64 struct address_space *mapping = vma->vm_file->f_mapping;
65 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
66 vma->vm_pgoff;
67 struct prio_tree_iter iter;
68 struct vm_area_struct *svma;
69 unsigned long saddr;
70 pte_t *spte = NULL;
71
72 if (!vma_shareable(vma, addr))
73 return;
74
75 mutex_lock(&mapping->i_mmap_mutex);
76 vma_prio_tree_foreach(svma, &iter, &mapping->i_mmap, idx, idx) {
77 if (svma == vma)
78 continue;
79
80 saddr = page_table_shareable(svma, vma, addr, idx);
81 if (saddr) {
82 spte = huge_pte_offset(svma->vm_mm, saddr);
83 if (spte) {
84 get_page(virt_to_page(spte));
85 break;
86 }
87 }
88 }
89
90 if (!spte)
91 goto out;
92
93 spin_lock(&mm->page_table_lock);
94 if (pud_none(*pud))
95 pud_populate(mm, pud, (pmd_t *)((unsigned long)spte & PAGE_MASK));
96 else
97 put_page(virt_to_page(spte));
98 spin_unlock(&mm->page_table_lock);
99out:
100 mutex_unlock(&mapping->i_mmap_mutex);
101}
102
103/*
104 * unmap huge page backed by shared pte.
105 *
106 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
107 * indicated by page_count > 1, unmap is achieved by clearing pud and
108 * decrementing the ref count. If count == 1, the pte page is not shared.
109 *
110 * called with vma->vm_mm->page_table_lock held.
111 *
112 * returns: 1 successfully unmapped a shared pte page
113 * 0 the underlying pte page is not shared, or it is the last user
114 */
115int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
116{
117 pgd_t *pgd = pgd_offset(mm, *addr);
118 pud_t *pud = pud_offset(pgd, *addr);
119
120 BUG_ON(page_count(virt_to_page(ptep)) == 0);
121 if (page_count(virt_to_page(ptep)) == 1)
122 return 0;
123
124 pud_clear(pud);
125 put_page(virt_to_page(ptep));
126 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
127 return 1;
128}
129
130pte_t *huge_pte_alloc(struct mm_struct *mm,
131 unsigned long addr, unsigned long sz)
132{
133 pgd_t *pgd;
134 pud_t *pud;
135 pte_t *pte = NULL;
136
137 pgd = pgd_offset(mm, addr);
138 pud = pud_alloc(mm, pgd, addr);
139 if (pud) {
140 if (sz == PUD_SIZE) {
141 pte = (pte_t *)pud;
142 } else {
143 BUG_ON(sz != PMD_SIZE);
144 if (pud_none(*pud))
145 huge_pmd_share(mm, addr, pud);
146 pte = (pte_t *) pmd_alloc(mm, pud, addr);
147 }
148 }
149 BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte));
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 = NULL;
159
160 pgd = pgd_offset(mm, addr);
161 if (pgd_present(*pgd)) {
162 pud = pud_offset(pgd, addr);
163 if (pud_present(*pud)) {
164 if (pud_large(*pud))
165 return (pte_t *)pud;
166 pmd = pmd_offset(pud, addr);
167 }
168 }
169 return (pte_t *) pmd;
170}
171
172#if 0 /* This is just for testing */
173struct page *
174follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
175{
176 unsigned long start = address;
177 int length = 1;
178 int nr;
179 struct page *page;
180 struct vm_area_struct *vma;
181
182 vma = find_vma(mm, addr);
183 if (!vma || !is_vm_hugetlb_page(vma))
184 return ERR_PTR(-EINVAL);
185
186 pte = huge_pte_offset(mm, address);
187
188 /* hugetlb should be locked, and hence, prefaulted */
189 WARN_ON(!pte || pte_none(*pte));
190
191 page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
192
193 WARN_ON(!PageHead(page));
194
195 return page;
196}
197
198int pmd_huge(pmd_t pmd)
199{
200 return 0;
201}
202
203int pud_huge(pud_t pud)
204{
205 return 0;
206}
207
208struct page *
209follow_huge_pmd(struct mm_struct *mm, unsigned long address,
210 pmd_t *pmd, int write)
211{
212 return NULL;
213}
214
215#else
216
217struct page *
218follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
219{
220 return ERR_PTR(-EINVAL);
221}
222
223int pmd_huge(pmd_t pmd)
224{
225 return !!(pmd_val(pmd) & _PAGE_PSE);
226}
227
228int pud_huge(pud_t pud)
229{
230 return !!(pud_val(pud) & _PAGE_PSE);
231}
232
233struct page *
234follow_huge_pmd(struct mm_struct *mm, unsigned long address,
235 pmd_t *pmd, int write)
236{
237 struct page *page;
238
239 page = pte_page(*(pte_t *)pmd);
240 if (page)
241 page += ((address & ~PMD_MASK) >> PAGE_SHIFT);
242 return page;
243}
244
245struct page *
246follow_huge_pud(struct mm_struct *mm, unsigned long address,
247 pud_t *pud, int write)
248{
249 struct page *page;
250
251 page = pte_page(*(pte_t *)pud);
252 if (page)
253 page += ((address & ~PUD_MASK) >> PAGE_SHIFT);
254 return page;
255}
256
257#endif
258
259/* x86_64 also uses this file */
260
261#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
262static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
263 unsigned long addr, unsigned long len,
264 unsigned long pgoff, unsigned long flags)
265{
266 struct hstate *h = hstate_file(file);
267 struct mm_struct *mm = current->mm;
268 struct vm_area_struct *vma;
269 unsigned long start_addr;
270
271 if (len > mm->cached_hole_size) {
272 start_addr = mm->free_area_cache;
273 } else {
274 start_addr = TASK_UNMAPPED_BASE;
275 mm->cached_hole_size = 0;
276 }
277
278full_search:
279 addr = ALIGN(start_addr, huge_page_size(h));
280
281 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
282 /* At this point: (!vma || addr < vma->vm_end). */
283 if (TASK_SIZE - len < addr) {
284 /*
285 * Start a new search - just in case we missed
286 * some holes.
287 */
288 if (start_addr != TASK_UNMAPPED_BASE) {
289 start_addr = TASK_UNMAPPED_BASE;
290 mm->cached_hole_size = 0;
291 goto full_search;
292 }
293 return -ENOMEM;
294 }
295 if (!vma || addr + len <= vma->vm_start) {
296 mm->free_area_cache = addr + len;
297 return addr;
298 }
299 if (addr + mm->cached_hole_size < vma->vm_start)
300 mm->cached_hole_size = vma->vm_start - addr;
301 addr = ALIGN(vma->vm_end, huge_page_size(h));
302 }
303}
304
305static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
306 unsigned long addr0, unsigned long len,
307 unsigned long pgoff, unsigned long flags)
308{
309 struct hstate *h = hstate_file(file);
310 struct mm_struct *mm = current->mm;
311 struct vm_area_struct *vma, *prev_vma;
312 unsigned long base = mm->mmap_base, addr = addr0;
313 unsigned long largest_hole = mm->cached_hole_size;
314 int first_time = 1;
315
316 /* don't allow allocations above current base */
317 if (mm->free_area_cache > base)
318 mm->free_area_cache = base;
319
320 if (len <= largest_hole) {
321 largest_hole = 0;
322 mm->free_area_cache = base;
323 }
324try_again:
325 /* make sure it can fit in the remaining address space */
326 if (mm->free_area_cache < len)
327 goto fail;
328
329 /* either no address requested or can't fit in requested address hole */
330 addr = (mm->free_area_cache - len) & huge_page_mask(h);
331 do {
332 /*
333 * Lookup failure means no vma is above this address,
334 * i.e. return with success:
335 */
336 if (!(vma = find_vma_prev(mm, addr, &prev_vma)))
337 return addr;
338
339 /*
340 * new region fits between prev_vma->vm_end and
341 * vma->vm_start, use it:
342 */
343 if (addr + len <= vma->vm_start &&
344 (!prev_vma || (addr >= prev_vma->vm_end))) {
345 /* remember the address as a hint for next time */
346 mm->cached_hole_size = largest_hole;
347 return (mm->free_area_cache = addr);
348 } else {
349 /* pull free_area_cache down to the first hole */
350 if (mm->free_area_cache == vma->vm_end) {
351 mm->free_area_cache = vma->vm_start;
352 mm->cached_hole_size = largest_hole;
353 }
354 }
355
356 /* remember the largest hole we saw so far */
357 if (addr + largest_hole < vma->vm_start)
358 largest_hole = vma->vm_start - addr;
359
360 /* try just below the current vma->vm_start */
361 addr = (vma->vm_start - len) & huge_page_mask(h);
362 } while (len <= vma->vm_start);
363
364fail:
365 /*
366 * if hint left us with no space for the requested
367 * mapping then try again:
368 */
369 if (first_time) {
370 mm->free_area_cache = base;
371 largest_hole = 0;
372 first_time = 0;
373 goto try_again;
374 }
375 /*
376 * A failed mmap() very likely causes application failure,
377 * so fall back to the bottom-up function here. This scenario
378 * can happen with large stack limits and large mmap()
379 * allocations.
380 */
381 mm->free_area_cache = TASK_UNMAPPED_BASE;
382 mm->cached_hole_size = ~0UL;
383 addr = hugetlb_get_unmapped_area_bottomup(file, addr0,
384 len, pgoff, flags);
385
386 /*
387 * Restore the topdown base:
388 */
389 mm->free_area_cache = base;
390 mm->cached_hole_size = ~0UL;
391
392 return addr;
393}
394
395unsigned long
396hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
397 unsigned long len, unsigned long pgoff, unsigned long flags)
398{
399 struct hstate *h = hstate_file(file);
400 struct mm_struct *mm = current->mm;
401 struct vm_area_struct *vma;
402
403 if (len & ~huge_page_mask(h))
404 return -EINVAL;
405 if (len > TASK_SIZE)
406 return -ENOMEM;
407
408 if (flags & MAP_FIXED) {
409 if (prepare_hugepage_range(file, addr, len))
410 return -EINVAL;
411 return addr;
412 }
413
414 if (addr) {
415 addr = ALIGN(addr, huge_page_size(h));
416 vma = find_vma(mm, addr);
417 if (TASK_SIZE - len >= addr &&
418 (!vma || addr + len <= vma->vm_start))
419 return addr;
420 }
421 if (mm->get_unmapped_area == arch_get_unmapped_area)
422 return hugetlb_get_unmapped_area_bottomup(file, addr, len,
423 pgoff, flags);
424 else
425 return hugetlb_get_unmapped_area_topdown(file, addr, len,
426 pgoff, flags);
427}
428
429#endif /*HAVE_ARCH_HUGETLB_UNMAPPED_AREA*/
430
431#ifdef CONFIG_X86_64
432static __init int setup_hugepagesz(char *opt)
433{
434 unsigned long ps = memparse(opt, &opt);
435 if (ps == PMD_SIZE) {
436 hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
437 } else if (ps == PUD_SIZE && cpu_has_gbpages) {
438 hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
439 } else {
440 printk(KERN_ERR "hugepagesz: Unsupported page size %lu M\n",
441 ps >> 20);
442 return 0;
443 }
444 return 1;
445}
446__setup("hugepagesz=", setup_hugepagesz);
447#endif