2 * arch/arm64/mm/hugetlbpage.c
4 * Copyright (C) 2013 Linaro Ltd.
6 * Based on arch/x86/mm/hugetlbpage.c.
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
18 #include <linux/init.h>
21 #include <linux/hugetlb.h>
22 #include <linux/pagemap.h>
23 #include <linux/err.h>
24 #include <linux/sysctl.h>
27 #include <asm/tlbflush.h>
28 #include <asm/pgalloc.h>
30 #ifdef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION
31 bool arch_hugetlb_migration_supported(struct hstate *h)
33 size_t pagesize = huge_page_size(h);
36 #ifdef CONFIG_ARM64_4K_PAGES
44 pr_warn("%s: unrecognized huge page size 0x%lx\n",
50 int pmd_huge(pmd_t pmd)
52 return pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT);
55 int pud_huge(pud_t pud)
57 #ifndef __PAGETABLE_PMD_FOLDED
58 return pud_val(pud) && !(pud_val(pud) & PUD_TABLE_BIT);
65 * Select all bits except the pfn
67 static inline pgprot_t pte_pgprot(pte_t pte)
69 unsigned long pfn = pte_pfn(pte);
71 return __pgprot(pte_val(pfn_pte(pfn, __pgprot(0))) ^ pte_val(pte));
74 static int find_num_contig(struct mm_struct *mm, unsigned long addr,
75 pte_t *ptep, size_t *pgsize)
77 pgd_t *pgdp = pgd_offset(mm, addr);
82 pudp = pud_offset(pgdp, addr);
83 pmdp = pmd_offset(pudp, addr);
84 if ((pte_t *)pmdp == ptep) {
91 static inline int num_contig_ptes(unsigned long size, size_t *pgsize)
98 #ifdef CONFIG_ARM64_4K_PAGES
106 contig_ptes = CONT_PMDS;
110 contig_ptes = CONT_PTES;
118 * Changing some bits of contiguous entries requires us to follow a
119 * Break-Before-Make approach, breaking the whole contiguous set
120 * before we can change any entries. See ARM DDI 0487A.k_iss10775,
121 * "Misprogramming of the Contiguous bit", page D4-1762.
123 * This helper performs the break step.
125 static pte_t get_clear_flush(struct mm_struct *mm,
128 unsigned long pgsize,
129 unsigned long ncontig)
131 pte_t orig_pte = huge_ptep_get(ptep);
132 bool valid = pte_valid(orig_pte);
133 unsigned long i, saddr = addr;
135 for (i = 0; i < ncontig; i++, addr += pgsize, ptep++) {
136 pte_t pte = ptep_get_and_clear(mm, addr, ptep);
139 * If HW_AFDBM is enabled, then the HW could turn on
140 * the dirty or accessed bit for any page in the set,
144 orig_pte = pte_mkdirty(orig_pte);
147 orig_pte = pte_mkyoung(orig_pte);
151 struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
152 flush_tlb_range(&vma, saddr, addr);
158 * Changing some bits of contiguous entries requires us to follow a
159 * Break-Before-Make approach, breaking the whole contiguous set
160 * before we can change any entries. See ARM DDI 0487A.k_iss10775,
161 * "Misprogramming of the Contiguous bit", page D4-1762.
163 * This helper performs the break step for use cases where the
164 * original pte is not needed.
166 static void clear_flush(struct mm_struct *mm,
169 unsigned long pgsize,
170 unsigned long ncontig)
172 struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
173 unsigned long i, saddr = addr;
175 for (i = 0; i < ncontig; i++, addr += pgsize, ptep++)
176 pte_clear(mm, addr, ptep);
178 flush_tlb_range(&vma, saddr, addr);
181 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
182 pte_t *ptep, pte_t pte)
187 unsigned long pfn, dpfn;
191 * Code needs to be expanded to handle huge swap and migration
192 * entries. Needed for HUGETLB and MEMORY_FAILURE.
194 WARN_ON(!pte_present(pte));
196 if (!pte_cont(pte)) {
197 set_pte_at(mm, addr, ptep, pte);
201 ncontig = find_num_contig(mm, addr, ptep, &pgsize);
203 dpfn = pgsize >> PAGE_SHIFT;
204 hugeprot = pte_pgprot(pte);
206 clear_flush(mm, addr, ptep, pgsize, ncontig);
208 for (i = 0; i < ncontig; i++, ptep++, addr += pgsize, pfn += dpfn)
209 set_pte_at(mm, addr, ptep, pfn_pte(pfn, hugeprot));
212 void set_huge_swap_pte_at(struct mm_struct *mm, unsigned long addr,
213 pte_t *ptep, pte_t pte, unsigned long sz)
218 ncontig = num_contig_ptes(sz, &pgsize);
220 for (i = 0; i < ncontig; i++, ptep++)
224 pte_t *huge_pte_alloc(struct mm_struct *mm,
225 unsigned long addr, unsigned long sz)
232 pgdp = pgd_offset(mm, addr);
233 pudp = pud_alloc(mm, pgdp, addr);
237 if (sz == PUD_SIZE) {
238 ptep = (pte_t *)pudp;
239 } else if (sz == (PAGE_SIZE * CONT_PTES)) {
240 pmdp = pmd_alloc(mm, pudp, addr);
242 WARN_ON(addr & (sz - 1));
244 * Note that if this code were ever ported to the
245 * 32-bit arm platform then it will cause trouble in
246 * the case where CONFIG_HIGHPTE is set, since there
247 * will be no pte_unmap() to correspond with this
250 ptep = pte_alloc_map(mm, pmdp, addr);
251 } else if (sz == PMD_SIZE) {
252 if (IS_ENABLED(CONFIG_ARCH_WANT_HUGE_PMD_SHARE) &&
253 pud_none(READ_ONCE(*pudp)))
254 ptep = huge_pmd_share(mm, addr, pudp);
256 ptep = (pte_t *)pmd_alloc(mm, pudp, addr);
257 } else if (sz == (PMD_SIZE * CONT_PMDS)) {
258 pmdp = pmd_alloc(mm, pudp, addr);
259 WARN_ON(addr & (sz - 1));
260 return (pte_t *)pmdp;
266 pte_t *huge_pte_offset(struct mm_struct *mm,
267 unsigned long addr, unsigned long sz)
273 pgdp = pgd_offset(mm, addr);
274 if (!pgd_present(READ_ONCE(*pgdp)))
277 pudp = pud_offset(pgdp, addr);
278 pud = READ_ONCE(*pudp);
279 if (sz != PUD_SIZE && pud_none(pud))
281 /* hugepage or swap? */
282 if (pud_huge(pud) || !pud_present(pud))
283 return (pte_t *)pudp;
284 /* table; check the next level */
286 if (sz == CONT_PMD_SIZE)
287 addr &= CONT_PMD_MASK;
289 pmdp = pmd_offset(pudp, addr);
290 pmd = READ_ONCE(*pmdp);
291 if (!(sz == PMD_SIZE || sz == CONT_PMD_SIZE) &&
294 if (pmd_huge(pmd) || !pmd_present(pmd))
295 return (pte_t *)pmdp;
297 if (sz == CONT_PTE_SIZE)
298 return pte_offset_kernel(pmdp, (addr & CONT_PTE_MASK));
303 pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
304 struct page *page, int writable)
306 size_t pagesize = huge_page_size(hstate_vma(vma));
308 if (pagesize == CONT_PTE_SIZE) {
309 entry = pte_mkcont(entry);
310 } else if (pagesize == CONT_PMD_SIZE) {
311 entry = pmd_pte(pmd_mkcont(pte_pmd(entry)));
312 } else if (pagesize != PUD_SIZE && pagesize != PMD_SIZE) {
313 pr_warn("%s: unrecognized huge page size 0x%lx\n",
319 void huge_pte_clear(struct mm_struct *mm, unsigned long addr,
320 pte_t *ptep, unsigned long sz)
325 ncontig = num_contig_ptes(sz, &pgsize);
327 for (i = 0; i < ncontig; i++, addr += pgsize, ptep++)
328 pte_clear(mm, addr, ptep);
331 pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
332 unsigned long addr, pte_t *ptep)
336 pte_t orig_pte = huge_ptep_get(ptep);
338 if (!pte_cont(orig_pte))
339 return ptep_get_and_clear(mm, addr, ptep);
341 ncontig = find_num_contig(mm, addr, ptep, &pgsize);
343 return get_clear_flush(mm, addr, ptep, pgsize, ncontig);
347 * huge_ptep_set_access_flags will update access flags (dirty, accesssed)
348 * and write permission.
350 * For a contiguous huge pte range we need to check whether or not write
351 * permission has to change only on the first pte in the set. Then for
352 * all the contiguous ptes we need to check whether or not there is a
353 * discrepancy between dirty or young.
355 static int __cont_access_flags_changed(pte_t *ptep, pte_t pte, int ncontig)
359 if (pte_write(pte) != pte_write(huge_ptep_get(ptep)))
362 for (i = 0; i < ncontig; i++) {
363 pte_t orig_pte = huge_ptep_get(ptep + i);
365 if (pte_dirty(pte) != pte_dirty(orig_pte))
368 if (pte_young(pte) != pte_young(orig_pte))
375 int huge_ptep_set_access_flags(struct vm_area_struct *vma,
376 unsigned long addr, pte_t *ptep,
377 pte_t pte, int dirty)
381 unsigned long pfn = pte_pfn(pte), dpfn;
386 return ptep_set_access_flags(vma, addr, ptep, pte, dirty);
388 ncontig = find_num_contig(vma->vm_mm, addr, ptep, &pgsize);
389 dpfn = pgsize >> PAGE_SHIFT;
391 if (!__cont_access_flags_changed(ptep, pte, ncontig))
394 orig_pte = get_clear_flush(vma->vm_mm, addr, ptep, pgsize, ncontig);
396 /* Make sure we don't lose the dirty or young state */
397 if (pte_dirty(orig_pte))
398 pte = pte_mkdirty(pte);
400 if (pte_young(orig_pte))
401 pte = pte_mkyoung(pte);
403 hugeprot = pte_pgprot(pte);
404 for (i = 0; i < ncontig; i++, ptep++, addr += pgsize, pfn += dpfn)
405 set_pte_at(vma->vm_mm, addr, ptep, pfn_pte(pfn, hugeprot));
410 void huge_ptep_set_wrprotect(struct mm_struct *mm,
411 unsigned long addr, pte_t *ptep)
413 unsigned long pfn, dpfn;
419 if (!pte_cont(READ_ONCE(*ptep))) {
420 ptep_set_wrprotect(mm, addr, ptep);
424 ncontig = find_num_contig(mm, addr, ptep, &pgsize);
425 dpfn = pgsize >> PAGE_SHIFT;
427 pte = get_clear_flush(mm, addr, ptep, pgsize, ncontig);
428 pte = pte_wrprotect(pte);
430 hugeprot = pte_pgprot(pte);
433 for (i = 0; i < ncontig; i++, ptep++, addr += pgsize, pfn += dpfn)
434 set_pte_at(mm, addr, ptep, pfn_pte(pfn, hugeprot));
437 void huge_ptep_clear_flush(struct vm_area_struct *vma,
438 unsigned long addr, pte_t *ptep)
443 if (!pte_cont(READ_ONCE(*ptep))) {
444 ptep_clear_flush(vma, addr, ptep);
448 ncontig = find_num_contig(vma->vm_mm, addr, ptep, &pgsize);
449 clear_flush(vma->vm_mm, addr, ptep, pgsize, ncontig);
452 static void __init add_huge_page_size(unsigned long size)
454 if (size_to_hstate(size))
457 hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
460 static int __init hugetlbpage_init(void)
462 #ifdef CONFIG_ARM64_4K_PAGES
463 add_huge_page_size(PUD_SIZE);
465 add_huge_page_size(PMD_SIZE * CONT_PMDS);
466 add_huge_page_size(PMD_SIZE);
467 add_huge_page_size(PAGE_SIZE * CONT_PTES);
471 arch_initcall(hugetlbpage_init);
473 static __init int setup_hugepagesz(char *opt)
475 unsigned long ps = memparse(opt, &opt);
478 #ifdef CONFIG_ARM64_4K_PAGES
481 case PMD_SIZE * CONT_PMDS:
483 case PAGE_SIZE * CONT_PTES:
484 add_huge_page_size(ps);
489 pr_err("hugepagesz: Unsupported page size %lu K\n", ps >> 10);
492 __setup("hugepagesz=", setup_hugepagesz);