xref: /openbmc/linux/arch/riscv/mm/hugetlbpage.c (revision 035c6e60074f7b5dccc90bfb64816bc82cde7239) 
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/hugetlb.h>
3 #include <linux/err.h>
4 
5 #ifdef CONFIG_RISCV_ISA_SVNAPOT
6 pte_t huge_ptep_get(pte_t *ptep)
7 {
8 	unsigned long pte_num;
9 	int i;
10 	pte_t orig_pte = ptep_get(ptep);
11 
12 	if (!pte_present(orig_pte) || !pte_napot(orig_pte))
13 		return orig_pte;
14 
15 	pte_num = napot_pte_num(napot_cont_order(orig_pte));
16 
17 	for (i = 0; i < pte_num; i++, ptep++) {
18 		pte_t pte = ptep_get(ptep);
19 
20 		if (pte_dirty(pte))
21 			orig_pte = pte_mkdirty(orig_pte);
22 
23 		if (pte_young(pte))
24 			orig_pte = pte_mkyoung(orig_pte);
25 	}
26 
27 	return orig_pte;
28 }
29 
30 pte_t *huge_pte_alloc(struct mm_struct *mm,
31 		      struct vm_area_struct *vma,
32 		      unsigned long addr,
33 		      unsigned long sz)
34 {
35 	unsigned long order;
36 	pte_t *pte = NULL;
37 	pgd_t *pgd;
38 	p4d_t *p4d;
39 	pud_t *pud;
40 	pmd_t *pmd;
41 
42 	pgd = pgd_offset(mm, addr);
43 	p4d = p4d_alloc(mm, pgd, addr);
44 	if (!p4d)
45 		return NULL;
46 
47 	pud = pud_alloc(mm, p4d, addr);
48 	if (!pud)
49 		return NULL;
50 
51 	if (sz == PUD_SIZE) {
52 		pte = (pte_t *)pud;
53 		goto out;
54 	}
55 
56 	if (sz == PMD_SIZE) {
57 		if (want_pmd_share(vma, addr) && pud_none(pudp_get(pud)))
58 			pte = huge_pmd_share(mm, vma, addr, pud);
59 		else
60 			pte = (pte_t *)pmd_alloc(mm, pud, addr);
61 		goto out;
62 	}
63 
64 	pmd = pmd_alloc(mm, pud, addr);
65 	if (!pmd)
66 		return NULL;
67 
68 	for_each_napot_order(order) {
69 		if (napot_cont_size(order) == sz) {
70 			pte = pte_alloc_huge(mm, pmd, addr & napot_cont_mask(order));
71 			break;
72 		}
73 	}
74 
75 out:
76 	if (pte) {
77 		pte_t pteval = ptep_get_lockless(pte);
78 
79 		WARN_ON_ONCE(pte_present(pteval) && !pte_huge(pteval));
80 	}
81 	return pte;
82 }
83 
84 pte_t *huge_pte_offset(struct mm_struct *mm,
85 		       unsigned long addr,
86 		       unsigned long sz)
87 {
88 	unsigned long order;
89 	pte_t *pte = NULL;
90 	pgd_t *pgd;
91 	p4d_t *p4d;
92 	pud_t *pud;
93 	pmd_t *pmd;
94 
95 	pgd = pgd_offset(mm, addr);
96 	if (!pgd_present(pgdp_get(pgd)))
97 		return NULL;
98 
99 	p4d = p4d_offset(pgd, addr);
100 	if (!p4d_present(p4dp_get(p4d)))
101 		return NULL;
102 
103 	pud = pud_offset(p4d, addr);
104 	if (sz == PUD_SIZE)
105 		/* must be pud huge, non-present or none */
106 		return (pte_t *)pud;
107 
108 	if (!pud_present(pudp_get(pud)))
109 		return NULL;
110 
111 	pmd = pmd_offset(pud, addr);
112 	if (sz == PMD_SIZE)
113 		/* must be pmd huge, non-present or none */
114 		return (pte_t *)pmd;
115 
116 	if (!pmd_present(pmdp_get(pmd)))
117 		return NULL;
118 
119 	for_each_napot_order(order) {
120 		if (napot_cont_size(order) == sz) {
121 			pte = pte_offset_huge(pmd, addr & napot_cont_mask(order));
122 			break;
123 		}
124 	}
125 	return pte;
126 }
127 
128 unsigned long hugetlb_mask_last_page(struct hstate *h)
129 {
130 	unsigned long hp_size = huge_page_size(h);
131 
132 	switch (hp_size) {
133 #ifndef __PAGETABLE_PMD_FOLDED
134 	case PUD_SIZE:
135 		return P4D_SIZE - PUD_SIZE;
136 #endif
137 	case PMD_SIZE:
138 		return PUD_SIZE - PMD_SIZE;
139 	case napot_cont_size(NAPOT_CONT64KB_ORDER):
140 		return PMD_SIZE - napot_cont_size(NAPOT_CONT64KB_ORDER);
141 	default:
142 		break;
143 	}
144 
145 	return 0UL;
146 }
147 
148 static pte_t get_clear_contig(struct mm_struct *mm,
149 			      unsigned long addr,
150 			      pte_t *ptep,
151 			      unsigned long ncontig)
152 {
153 	pte_t pte, tmp_pte;
154 	bool present;
155 
156 	pte = ptep_get_and_clear(mm, addr, ptep);
157 	present = pte_present(pte);
158 	while (--ncontig) {
159 		ptep++;
160 		addr += PAGE_SIZE;
161 		tmp_pte = ptep_get_and_clear(mm, addr, ptep);
162 		if (present) {
163 			if (pte_dirty(tmp_pte))
164 				pte = pte_mkdirty(pte);
165 			if (pte_young(tmp_pte))
166 				pte = pte_mkyoung(pte);
167 		}
168 	}
169 	return pte;
170 }
171 
172 static pte_t get_clear_contig_flush(struct mm_struct *mm,
173 				    unsigned long addr,
174 				    pte_t *ptep,
175 				    unsigned long pte_num)
176 {
177 	pte_t orig_pte = get_clear_contig(mm, addr, ptep, pte_num);
178 	struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
179 	bool valid = !pte_none(orig_pte);
180 
181 	if (valid)
182 		flush_tlb_range(&vma, addr, addr + (PAGE_SIZE * pte_num));
183 
184 	return orig_pte;
185 }
186 
187 pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags)
188 {
189 	unsigned long order;
190 
191 	for_each_napot_order(order) {
192 		if (shift == napot_cont_shift(order)) {
193 			entry = pte_mknapot(entry, order);
194 			break;
195 		}
196 	}
197 	if (order == NAPOT_ORDER_MAX)
198 		entry = pte_mkhuge(entry);
199 
200 	return entry;
201 }
202 
203 static void clear_flush(struct mm_struct *mm,
204 			unsigned long addr,
205 			pte_t *ptep,
206 			unsigned long pgsize,
207 			unsigned long ncontig)
208 {
209 	struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
210 	unsigned long i, saddr = addr;
211 
212 	for (i = 0; i < ncontig; i++, addr += pgsize, ptep++)
213 		ptep_get_and_clear(mm, addr, ptep);
214 
215 	flush_tlb_range(&vma, saddr, addr);
216 }
217 
218 static int num_contig_ptes_from_size(unsigned long sz, size_t *pgsize)
219 {
220 	unsigned long hugepage_shift;
221 
222 	if (sz >= PGDIR_SIZE)
223 		hugepage_shift = PGDIR_SHIFT;
224 	else if (sz >= P4D_SIZE)
225 		hugepage_shift = P4D_SHIFT;
226 	else if (sz >= PUD_SIZE)
227 		hugepage_shift = PUD_SHIFT;
228 	else if (sz >= PMD_SIZE)
229 		hugepage_shift = PMD_SHIFT;
230 	else
231 		hugepage_shift = PAGE_SHIFT;
232 
233 	*pgsize = 1 << hugepage_shift;
234 
235 	return sz >> hugepage_shift;
236 }
237 
238 /*
239  * When dealing with NAPOT mappings, the privileged specification indicates that
240  * "if an update needs to be made, the OS generally should first mark all of the
241  * PTEs invalid, then issue SFENCE.VMA instruction(s) covering all 4 KiB regions
242  * within the range, [...] then update the PTE(s), as described in Section
243  * 4.2.1.". That's the equivalent of the Break-Before-Make approach used by
244  * arm64.
245  */
246 void set_huge_pte_at(struct mm_struct *mm,
247 		     unsigned long addr,
248 		     pte_t *ptep,
249 		     pte_t pte,
250 		     unsigned long sz)
251 {
252 	size_t pgsize;
253 	int i, pte_num;
254 
255 	pte_num = num_contig_ptes_from_size(sz, &pgsize);
256 
257 	if (!pte_present(pte)) {
258 		for (i = 0; i < pte_num; i++, ptep++, addr += pgsize)
259 			set_ptes(mm, addr, ptep, pte, 1);
260 		return;
261 	}
262 
263 	if (!pte_napot(pte)) {
264 		set_ptes(mm, addr, ptep, pte, 1);
265 		return;
266 	}
267 
268 	clear_flush(mm, addr, ptep, pgsize, pte_num);
269 
270 	for (i = 0; i < pte_num; i++, ptep++, addr += pgsize)
271 		set_pte_at(mm, addr, ptep, pte);
272 }
273 
274 int huge_ptep_set_access_flags(struct vm_area_struct *vma,
275 			       unsigned long addr,
276 			       pte_t *ptep,
277 			       pte_t pte,
278 			       int dirty)
279 {
280 	struct mm_struct *mm = vma->vm_mm;
281 	unsigned long order;
282 	pte_t orig_pte;
283 	int i, pte_num;
284 
285 	if (!pte_napot(pte))
286 		return ptep_set_access_flags(vma, addr, ptep, pte, dirty);
287 
288 	order = napot_cont_order(pte);
289 	pte_num = napot_pte_num(order);
290 	ptep = huge_pte_offset(mm, addr, napot_cont_size(order));
291 	orig_pte = get_clear_contig_flush(mm, addr, ptep, pte_num);
292 
293 	if (pte_dirty(orig_pte))
294 		pte = pte_mkdirty(pte);
295 
296 	if (pte_young(orig_pte))
297 		pte = pte_mkyoung(pte);
298 
299 	for (i = 0; i < pte_num; i++, addr += PAGE_SIZE, ptep++)
300 		set_pte_at(mm, addr, ptep, pte);
301 
302 	return true;
303 }
304 
305 pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
306 			      unsigned long addr,
307 			      pte_t *ptep, unsigned long sz)
308 {
309 	size_t pgsize;
310 	pte_t orig_pte = ptep_get(ptep);
311 	int pte_num;
312 
313 	if (!pte_napot(orig_pte))
314 		return ptep_get_and_clear(mm, addr, ptep);
315 
316 	pte_num = num_contig_ptes_from_size(sz, &pgsize);
317 
318 	return get_clear_contig(mm, addr, ptep, pte_num);
319 }
320 
321 void huge_ptep_set_wrprotect(struct mm_struct *mm,
322 			     unsigned long addr,
323 			     pte_t *ptep)
324 {
325 	pte_t pte = ptep_get(ptep);
326 	unsigned long order;
327 	pte_t orig_pte;
328 	int i, pte_num;
329 
330 	if (!pte_napot(pte)) {
331 		ptep_set_wrprotect(mm, addr, ptep);
332 		return;
333 	}
334 
335 	order = napot_cont_order(pte);
336 	pte_num = napot_pte_num(order);
337 	ptep = huge_pte_offset(mm, addr, napot_cont_size(order));
338 	orig_pte = get_clear_contig_flush(mm, addr, ptep, pte_num);
339 
340 	orig_pte = pte_wrprotect(orig_pte);
341 
342 	for (i = 0; i < pte_num; i++, addr += PAGE_SIZE, ptep++)
343 		set_pte_at(mm, addr, ptep, orig_pte);
344 }
345 
346 pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
347 			    unsigned long addr,
348 			    pte_t *ptep)
349 {
350 	pte_t pte = ptep_get(ptep);
351 	int pte_num;
352 
353 	if (!pte_napot(pte))
354 		return ptep_clear_flush(vma, addr, ptep);
355 
356 	pte_num = napot_pte_num(napot_cont_order(pte));
357 
358 	return get_clear_contig_flush(vma->vm_mm, addr, ptep, pte_num);
359 }
360 
361 void huge_pte_clear(struct mm_struct *mm,
362 		    unsigned long addr,
363 		    pte_t *ptep,
364 		    unsigned long sz)
365 {
366 	size_t pgsize;
367 	pte_t pte = ptep_get(ptep);
368 	int i, pte_num;
369 
370 	if (!pte_napot(pte)) {
371 		pte_clear(mm, addr, ptep);
372 		return;
373 	}
374 
375 	pte_num = num_contig_ptes_from_size(sz, &pgsize);
376 
377 	for (i = 0; i < pte_num; i++, addr += pgsize, ptep++)
378 		pte_clear(mm, addr, ptep);
379 }
380 
381 static bool is_napot_size(unsigned long size)
382 {
383 	unsigned long order;
384 
385 	if (!has_svnapot())
386 		return false;
387 
388 	for_each_napot_order(order) {
389 		if (size == napot_cont_size(order))
390 			return true;
391 	}
392 	return false;
393 }
394 
395 static __init int napot_hugetlbpages_init(void)
396 {
397 	if (has_svnapot()) {
398 		unsigned long order;
399 
400 		for_each_napot_order(order)
401 			hugetlb_add_hstate(order);
402 	}
403 	return 0;
404 }
405 arch_initcall(napot_hugetlbpages_init);
406 
407 #else
408 
409 static bool is_napot_size(unsigned long size)
410 {
411 	return false;
412 }
413 
414 #endif /*CONFIG_RISCV_ISA_SVNAPOT*/
415 
416 int pud_huge(pud_t pud)
417 {
418 	return pud_leaf(pud);
419 }
420 
421 int pmd_huge(pmd_t pmd)
422 {
423 	return pmd_leaf(pmd);
424 }
425 
426 static bool __hugetlb_valid_size(unsigned long size)
427 {
428 	if (size == HPAGE_SIZE)
429 		return true;
430 	else if (IS_ENABLED(CONFIG_64BIT) && size == PUD_SIZE)
431 		return true;
432 	else if (is_napot_size(size))
433 		return true;
434 	else
435 		return false;
436 }
437 
438 bool __init arch_hugetlb_valid_size(unsigned long size)
439 {
440 	return __hugetlb_valid_size(size);
441 }
442 
443 #ifdef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION
444 bool arch_hugetlb_migration_supported(struct hstate *h)
445 {
446 	return __hugetlb_valid_size(huge_page_size(h));
447 }
448 #endif
449 
450 #ifdef CONFIG_CONTIG_ALLOC
451 static __init int gigantic_pages_init(void)
452 {
453 	/* With CONTIG_ALLOC, we can allocate gigantic pages at runtime */
454 	if (IS_ENABLED(CONFIG_64BIT))
455 		hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
456 	return 0;
457 }
458 arch_initcall(gigantic_pages_init);
459 #endif
460