diff options
| -rw-r--r-- | arch/arm64/mm/hugetlbpage.c | 112 |
1 files changed, 91 insertions, 21 deletions
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c index 08deed7c71f0..b82df85fe920 100644 --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c @@ -68,6 +68,66 @@ static int find_num_contig(struct mm_struct *mm, unsigned long addr, return CONT_PTES; } +/* + * 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_flush(struct mm_struct *mm, + unsigned long addr, + pte_t *ptep, + unsigned long pgsize, + unsigned long ncontig) +{ + struct vm_area_struct vma = { .vm_mm = mm }; + pte_t orig_pte = huge_ptep_get(ptep); + bool valid = pte_valid(orig_pte); + unsigned long i, saddr = addr; + + 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 bit for any page in the set, so check + * them all. All hugetlb entries are already young. + */ + if (pte_dirty(pte)) + orig_pte = pte_mkdirty(orig_pte); + } + + if (valid) + flush_tlb_range(&vma, saddr, addr); + 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 = { .vm_mm = mm }; + unsigned long i, saddr = addr; + + for (i = 0; i < ncontig; i++, addr += pgsize, ptep++) + pte_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) { @@ -93,6 +153,8 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, 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) { pr_debug("%s: set pte %p to 0x%llx\n", __func__, ptep, pte_val(pfn_pte(pfn, hugeprot))); @@ -194,7 +256,7 @@ pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma, pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { - int ncontig, i; + int ncontig; size_t pgsize; pte_t orig_pte = huge_ptep_get(ptep); @@ -202,17 +264,8 @@ pte_t huge_ptep_get_and_clear(struct mm_struct *mm, return ptep_get_and_clear(mm, addr, ptep); ncontig = find_num_contig(mm, addr, ptep, &pgsize); - for (i = 0; i < ncontig; i++, addr += pgsize, ptep++) { - /* - * If HW_AFDBM is enabled, then the HW could - * turn on the dirty bit for any of the page - * in the set, so check them all. - */ - if (pte_dirty(ptep_get_and_clear(mm, addr, ptep))) - orig_pte = pte_mkdirty(orig_pte); - } - return orig_pte; + return get_clear_flush(mm, addr, ptep, pgsize, ncontig); } int huge_ptep_set_access_flags(struct vm_area_struct *vma, @@ -223,18 +276,25 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma, size_t pgsize = 0; unsigned long pfn = pte_pfn(pte), dpfn; 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(vma->vm_mm, addr, ptep, &pgsize); dpfn = pgsize >> PAGE_SHIFT; - hugeprot = pte_pgprot(pte); - for (i = 0; i < ncontig; i++, ptep++, addr += pgsize, pfn += dpfn) { - changed |= ptep_set_access_flags(vma, addr, ptep, - pfn_pte(pfn, hugeprot), dirty); - } + orig_pte = get_clear_flush(vma->vm_mm, addr, ptep, pgsize, ncontig); + if (!pte_same(orig_pte, pte)) + changed = 1; + + /* Make sure we don't lose the dirty state */ + if (pte_dirty(orig_pte)) + pte = pte_mkdirty(pte); + + hugeprot = pte_pgprot(pte); + for (i = 0; i < ncontig; i++, ptep++, addr += pgsize, pfn += dpfn) + set_pte_at(vma->vm_mm, addr, ptep, pfn_pte(pfn, hugeprot)); return changed; } @@ -242,8 +302,11 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma, 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(*ptep)) { ptep_set_wrprotect(mm, addr, ptep); @@ -251,15 +314,23 @@ void huge_ptep_set_wrprotect(struct mm_struct *mm, } ncontig = find_num_contig(mm, addr, ptep, &pgsize); - for (i = 0; i < ncontig; i++, ptep++, addr += pgsize) - ptep_set_wrprotect(mm, addr, ptep); + dpfn = pgsize >> PAGE_SHIFT; + + pte = get_clear_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)); } void huge_ptep_clear_flush(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep) { - int ncontig, i; size_t pgsize; + int ncontig; if (!pte_cont(*ptep)) { ptep_clear_flush(vma, addr, ptep); @@ -267,8 +338,7 @@ void huge_ptep_clear_flush(struct vm_area_struct *vma, } ncontig = find_num_contig(vma->vm_mm, addr, ptep, &pgsize); - for (i = 0; i < ncontig; i++, ptep++, addr += pgsize) - ptep_clear_flush(vma, addr, ptep); + clear_flush(vma->vm_mm, addr, ptep, pgsize, ncontig); } static __init int setup_hugepagesz(char *opt) |