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Diffstat (limited to 'arch/arm64/mm/hugetlbpage.c')
| -rw-r--r-- | arch/arm64/mm/hugetlbpage.c | 566 |
1 files changed, 566 insertions, 0 deletions
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c new file mode 100644 index 000000000..13fd59222 --- /dev/null +++ b/arch/arm64/mm/hugetlbpage.c @@ -0,0 +1,566 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * arch/arm64/mm/hugetlbpage.c + * + * Copyright (C) 2013 Linaro Ltd. + * + * Based on arch/x86/mm/hugetlbpage.c. + */ + +#include <linux/init.h> +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/hugetlb.h> +#include <linux/pagemap.h> +#include <linux/err.h> +#include <linux/sysctl.h> +#include <asm/mman.h> +#include <asm/tlb.h> +#include <asm/tlbflush.h> + +/* + * HugeTLB Support Matrix + * + * --------------------------------------------------- + * | Page Size | CONT PTE | PMD | CONT PMD | PUD | + * --------------------------------------------------- + * | 4K | 64K | 2M | 32M | 1G | + * | 16K | 2M | 32M | 1G | | + * | 64K | 2M | 512M | 16G | | + * --------------------------------------------------- + */ + +/* + * Reserve CMA areas for the largest supported gigantic + * huge page when requested. Any other smaller gigantic + * huge pages could still be served from those areas. + */ +#ifdef CONFIG_CMA +void __init arm64_hugetlb_cma_reserve(void) +{ + int order; + + if (pud_sect_supported()) + order = PUD_SHIFT - PAGE_SHIFT; + else + order = CONT_PMD_SHIFT - PAGE_SHIFT; + + /* + * HugeTLB CMA reservation is required for gigantic + * huge pages which could not be allocated via the + * page allocator. Just warn if there is any change + * breaking this assumption. + */ + WARN_ON(order <= MAX_ORDER); + hugetlb_cma_reserve(order); +} +#endif /* CONFIG_CMA */ + +static bool __hugetlb_valid_size(unsigned long size) +{ + switch (size) { +#ifndef __PAGETABLE_PMD_FOLDED + case PUD_SIZE: + return pud_sect_supported(); +#endif + case CONT_PMD_SIZE: + case PMD_SIZE: + case CONT_PTE_SIZE: + return true; + } + + return false; +} + +#ifdef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION +bool arch_hugetlb_migration_supported(struct hstate *h) +{ + size_t pagesize = huge_page_size(h); + + if (!__hugetlb_valid_size(pagesize)) { + pr_warn("%s: unrecognized huge page size 0x%lx\n", + __func__, pagesize); + return false; + } + return true; +} +#endif + +int pmd_huge(pmd_t pmd) +{ + return pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT); +} + +int pud_huge(pud_t pud) +{ +#ifndef __PAGETABLE_PMD_FOLDED + return pud_val(pud) && !(pud_val(pud) & PUD_TABLE_BIT); +#else + return 0; +#endif +} + +static int find_num_contig(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, size_t *pgsize) +{ + pgd_t *pgdp = pgd_offset(mm, addr); + p4d_t *p4dp; + pud_t *pudp; + pmd_t *pmdp; + + *pgsize = PAGE_SIZE; + p4dp = p4d_offset(pgdp, addr); + pudp = pud_offset(p4dp, addr); + pmdp = pmd_offset(pudp, addr); + if ((pte_t *)pmdp == ptep) { + *pgsize = PMD_SIZE; + return CONT_PMDS; + } + return CONT_PTES; +} + +static inline int num_contig_ptes(unsigned long size, size_t *pgsize) +{ + int contig_ptes = 0; + + *pgsize = size; + + switch (size) { +#ifndef __PAGETABLE_PMD_FOLDED + case PUD_SIZE: + if (pud_sect_supported()) + contig_ptes = 1; + break; +#endif + case PMD_SIZE: + contig_ptes = 1; + break; + case CONT_PMD_SIZE: + *pgsize = PMD_SIZE; + contig_ptes = CONT_PMDS; + break; + case CONT_PTE_SIZE: + *pgsize = PAGE_SIZE; + contig_ptes = CONT_PTES; + break; + } + + return contig_ptes; +} + +pte_t huge_ptep_get(pte_t *ptep) +{ + int ncontig, i; + size_t pgsize; + pte_t orig_pte = ptep_get(ptep); + + if (!pte_present(orig_pte) || !pte_cont(orig_pte)) + return orig_pte; + + ncontig = num_contig_ptes(page_size(pte_page(orig_pte)), &pgsize); + for (i = 0; i < ncontig; i++, ptep++) { + pte_t pte = ptep_get(ptep); + + if (pte_dirty(pte)) + orig_pte = pte_mkdirty(orig_pte); + + if (pte_young(pte)) + orig_pte = pte_mkyoung(orig_pte); + } + return orig_pte; +} + +/* + * Changing some bits of contiguous entries requires us to follow a + * Break-Before-Make approach, breaking the whole contiguous set + * before we can change any entries. See ARM DDI 0487A.k_iss10775, + * "Misprogramming of the Contiguous bit", page D4-1762. + * + * This helper performs the break step. + */ +static pte_t get_clear_contig(struct mm_struct *mm, + unsigned long addr, + pte_t *ptep, + unsigned long pgsize, + unsigned long ncontig) +{ + pte_t orig_pte = ptep_get(ptep); + unsigned long i; + + for (i = 0; i < ncontig; i++, addr += pgsize, ptep++) { + pte_t pte = ptep_get_and_clear(mm, addr, ptep); + + /* + * If HW_AFDBM is enabled, then the HW could turn on + * the dirty or accessed bit for any page in the set, + * so check them all. + */ + if (pte_dirty(pte)) + orig_pte = pte_mkdirty(orig_pte); + + if (pte_young(pte)) + orig_pte = pte_mkyoung(orig_pte); + } + return orig_pte; +} + +static pte_t get_clear_contig_flush(struct mm_struct *mm, + unsigned long addr, + pte_t *ptep, + unsigned long pgsize, + unsigned long ncontig) +{ + pte_t orig_pte = get_clear_contig(mm, addr, ptep, pgsize, ncontig); + struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0); + + flush_tlb_range(&vma, addr, addr + (pgsize * ncontig)); + return orig_pte; +} + +/* + * Changing some bits of contiguous entries requires us to follow a + * Break-Before-Make approach, breaking the whole contiguous set + * before we can change any entries. See ARM DDI 0487A.k_iss10775, + * "Misprogramming of the Contiguous bit", page D4-1762. + * + * This helper performs the break step for use cases where the + * original pte is not needed. + */ +static void clear_flush(struct mm_struct *mm, + unsigned long addr, + pte_t *ptep, + unsigned long pgsize, + unsigned long ncontig) +{ + struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0); + unsigned long i, saddr = addr; + + for (i = 0; i < ncontig; i++, addr += pgsize, ptep++) + ptep_clear(mm, addr, ptep); + + flush_tlb_range(&vma, saddr, addr); +} + +void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, pte_t pte, unsigned long sz) +{ + size_t pgsize; + int i; + int ncontig; + unsigned long pfn, dpfn; + pgprot_t hugeprot; + + ncontig = num_contig_ptes(sz, &pgsize); + + if (!pte_present(pte)) { + for (i = 0; i < ncontig; i++, ptep++, addr += pgsize) + set_pte_at(mm, addr, ptep, pte); + return; + } + + if (!pte_cont(pte)) { + set_pte_at(mm, addr, ptep, pte); + return; + } + + pfn = pte_pfn(pte); + dpfn = pgsize >> PAGE_SHIFT; + hugeprot = pte_pgprot(pte); + + clear_flush(mm, addr, ptep, pgsize, ncontig); + + for (i = 0; i < ncontig; i++, ptep++, addr += pgsize, pfn += dpfn) + set_pte_at(mm, addr, ptep, pfn_pte(pfn, hugeprot)); +} + +pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma, + unsigned long addr, unsigned long sz) +{ + pgd_t *pgdp; + p4d_t *p4dp; + pud_t *pudp; + pmd_t *pmdp; + pte_t *ptep = NULL; + + pgdp = pgd_offset(mm, addr); + p4dp = p4d_offset(pgdp, addr); + pudp = pud_alloc(mm, p4dp, addr); + if (!pudp) + return NULL; + + if (sz == PUD_SIZE) { + ptep = (pte_t *)pudp; + } else if (sz == (CONT_PTE_SIZE)) { + pmdp = pmd_alloc(mm, pudp, addr); + if (!pmdp) + return NULL; + + WARN_ON(addr & (sz - 1)); + ptep = pte_alloc_huge(mm, pmdp, addr); + } else if (sz == PMD_SIZE) { + if (want_pmd_share(vma, addr) && pud_none(READ_ONCE(*pudp))) + ptep = huge_pmd_share(mm, vma, addr, pudp); + else + ptep = (pte_t *)pmd_alloc(mm, pudp, addr); + } else if (sz == (CONT_PMD_SIZE)) { + pmdp = pmd_alloc(mm, pudp, addr); + WARN_ON(addr & (sz - 1)); + return (pte_t *)pmdp; + } + + return ptep; +} + +pte_t *huge_pte_offset(struct mm_struct *mm, + unsigned long addr, unsigned long sz) +{ + pgd_t *pgdp; + p4d_t *p4dp; + pud_t *pudp, pud; + pmd_t *pmdp, pmd; + + pgdp = pgd_offset(mm, addr); + if (!pgd_present(READ_ONCE(*pgdp))) + return NULL; + + p4dp = p4d_offset(pgdp, addr); + if (!p4d_present(READ_ONCE(*p4dp))) + return NULL; + + pudp = pud_offset(p4dp, addr); + pud = READ_ONCE(*pudp); + if (sz != PUD_SIZE && pud_none(pud)) + return NULL; + /* hugepage or swap? */ + if (pud_huge(pud) || !pud_present(pud)) + return (pte_t *)pudp; + /* table; check the next level */ + + if (sz == CONT_PMD_SIZE) + addr &= CONT_PMD_MASK; + + pmdp = pmd_offset(pudp, addr); + pmd = READ_ONCE(*pmdp); + if (!(sz == PMD_SIZE || sz == CONT_PMD_SIZE) && + pmd_none(pmd)) + return NULL; + if (pmd_huge(pmd) || !pmd_present(pmd)) + return (pte_t *)pmdp; + + if (sz == CONT_PTE_SIZE) + return pte_offset_huge(pmdp, (addr & CONT_PTE_MASK)); + + return NULL; +} + +unsigned long hugetlb_mask_last_page(struct hstate *h) +{ + unsigned long hp_size = huge_page_size(h); + + switch (hp_size) { +#ifndef __PAGETABLE_PMD_FOLDED + case PUD_SIZE: + return PGDIR_SIZE - PUD_SIZE; +#endif + case CONT_PMD_SIZE: + return PUD_SIZE - CONT_PMD_SIZE; + case PMD_SIZE: + return PUD_SIZE - PMD_SIZE; + case CONT_PTE_SIZE: + return PMD_SIZE - CONT_PTE_SIZE; + default: + break; + } + + return 0UL; +} + +pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags) +{ + size_t pagesize = 1UL << shift; + + entry = pte_mkhuge(entry); + if (pagesize == CONT_PTE_SIZE) { + entry = pte_mkcont(entry); + } else if (pagesize == CONT_PMD_SIZE) { + entry = pmd_pte(pmd_mkcont(pte_pmd(entry))); + } else if (pagesize != PUD_SIZE && pagesize != PMD_SIZE) { + pr_warn("%s: unrecognized huge page size 0x%lx\n", + __func__, pagesize); + } + return entry; +} + +void huge_pte_clear(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, unsigned long sz) +{ + int i, ncontig; + size_t pgsize; + + ncontig = num_contig_ptes(sz, &pgsize); + + for (i = 0; i < ncontig; i++, addr += pgsize, ptep++) + pte_clear(mm, addr, ptep); +} + +pte_t huge_ptep_get_and_clear(struct mm_struct *mm, + unsigned long addr, pte_t *ptep) +{ + int ncontig; + size_t pgsize; + pte_t orig_pte = ptep_get(ptep); + + if (!pte_cont(orig_pte)) + return ptep_get_and_clear(mm, addr, ptep); + + ncontig = find_num_contig(mm, addr, ptep, &pgsize); + + return get_clear_contig(mm, addr, ptep, pgsize, ncontig); +} + +/* + * huge_ptep_set_access_flags will update access flags (dirty, accesssed) + * and write permission. + * + * For a contiguous huge pte range we need to check whether or not write + * permission has to change only on the first pte in the set. Then for + * all the contiguous ptes we need to check whether or not there is a + * discrepancy between dirty or young. + */ +static int __cont_access_flags_changed(pte_t *ptep, pte_t pte, int ncontig) +{ + int i; + + if (pte_write(pte) != pte_write(ptep_get(ptep))) + return 1; + + for (i = 0; i < ncontig; i++) { + pte_t orig_pte = ptep_get(ptep + i); + + if (pte_dirty(pte) != pte_dirty(orig_pte)) + return 1; + + if (pte_young(pte) != pte_young(orig_pte)) + return 1; + } + + return 0; +} + +int huge_ptep_set_access_flags(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + pte_t pte, int dirty) +{ + int ncontig, i; + size_t pgsize = 0; + unsigned long pfn = pte_pfn(pte), dpfn; + struct mm_struct *mm = vma->vm_mm; + pgprot_t hugeprot; + pte_t orig_pte; + + if (!pte_cont(pte)) + return ptep_set_access_flags(vma, addr, ptep, pte, dirty); + + ncontig = find_num_contig(mm, addr, ptep, &pgsize); + dpfn = pgsize >> PAGE_SHIFT; + + if (!__cont_access_flags_changed(ptep, pte, ncontig)) + return 0; + + orig_pte = get_clear_contig_flush(mm, addr, ptep, pgsize, ncontig); + + /* Make sure we don't lose the dirty or young state */ + if (pte_dirty(orig_pte)) + pte = pte_mkdirty(pte); + + if (pte_young(orig_pte)) + pte = pte_mkyoung(pte); + + hugeprot = pte_pgprot(pte); + for (i = 0; i < ncontig; i++, ptep++, addr += pgsize, pfn += dpfn) + set_pte_at(mm, addr, ptep, pfn_pte(pfn, hugeprot)); + + return 1; +} + +void huge_ptep_set_wrprotect(struct mm_struct *mm, + unsigned long addr, pte_t *ptep) +{ + unsigned long pfn, dpfn; + pgprot_t hugeprot; + int ncontig, i; + size_t pgsize; + pte_t pte; + + if (!pte_cont(READ_ONCE(*ptep))) { + ptep_set_wrprotect(mm, addr, ptep); + return; + } + + ncontig = find_num_contig(mm, addr, ptep, &pgsize); + dpfn = pgsize >> PAGE_SHIFT; + + pte = get_clear_contig_flush(mm, addr, ptep, pgsize, ncontig); + pte = pte_wrprotect(pte); + + hugeprot = pte_pgprot(pte); + pfn = pte_pfn(pte); + + for (i = 0; i < ncontig; i++, ptep++, addr += pgsize, pfn += dpfn) + set_pte_at(mm, addr, ptep, pfn_pte(pfn, hugeprot)); +} + +pte_t huge_ptep_clear_flush(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep) +{ + struct mm_struct *mm = vma->vm_mm; + size_t pgsize; + int ncontig; + + if (!pte_cont(READ_ONCE(*ptep))) + return ptep_clear_flush(vma, addr, ptep); + + ncontig = find_num_contig(mm, addr, ptep, &pgsize); + return get_clear_contig_flush(mm, addr, ptep, pgsize, ncontig); +} + +static int __init hugetlbpage_init(void) +{ + if (pud_sect_supported()) + hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT); + + hugetlb_add_hstate(CONT_PMD_SHIFT - PAGE_SHIFT); + hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT); + hugetlb_add_hstate(CONT_PTE_SHIFT - PAGE_SHIFT); + + return 0; +} +arch_initcall(hugetlbpage_init); + +bool __init arch_hugetlb_valid_size(unsigned long size) +{ + return __hugetlb_valid_size(size); +} + +pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep) +{ + if (IS_ENABLED(CONFIG_ARM64_ERRATUM_2645198) && + cpus_have_const_cap(ARM64_WORKAROUND_2645198)) { + /* + * Break-before-make (BBM) is required for all user space mappings + * when the permission changes from executable to non-executable + * in cases where cpu is affected with errata #2645198. + */ + if (pte_user_exec(READ_ONCE(*ptep))) + return huge_ptep_clear_flush(vma, addr, ptep); + } + return huge_ptep_get_and_clear(vma->vm_mm, addr, ptep); +} + +void huge_ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep, + pte_t old_pte, pte_t pte) +{ + unsigned long psize = huge_page_size(hstate_vma(vma)); + + set_huge_pte_at(vma->vm_mm, addr, ptep, pte, psize); +} |