From c3824e18d3f3946015ac641d46fdeeefd30bfd66 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Thu, 15 Oct 2020 20:04:46 -0700 Subject: mm/debug_vm_pgtable/set_pte/pmd/pud: don't use set_*_at to update an existing pte entry set_pte_at() should not be used to set a pte entry at locations that already holds a valid pte entry. Architectures like ppc64 don't do TLB invalidate in set_pte_at() and hence expect it to be used to set locations that are not a valid PTE. Link: https://lkml.kernel.org/r/20200902114222.181353-8-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Reviewed-by: Anshuman Khandual Cc: Christophe Leroy Cc: Michael Ellerman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/debug_vm_pgtable.c | 35 +++++++++++++++-------------------- 1 file changed, 15 insertions(+), 20 deletions(-) (limited to 'mm/debug_vm_pgtable.c') diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c index 8704901f6bd8..2ba5ec866f53 100644 --- a/mm/debug_vm_pgtable.c +++ b/mm/debug_vm_pgtable.c @@ -79,15 +79,18 @@ static void __init pte_advanced_tests(struct mm_struct *mm, { pte_t pte = pfn_pte(pfn, prot); + /* + * Architectures optimize set_pte_at by avoiding TLB flush. + * This requires set_pte_at to be not used to update an + * existing pte entry. Clear pte before we do set_pte_at + */ + pr_debug("Validating PTE advanced\n"); pte = pfn_pte(pfn, prot); set_pte_at(mm, vaddr, ptep, pte); ptep_set_wrprotect(mm, vaddr, ptep); pte = ptep_get(ptep); WARN_ON(pte_write(pte)); - - pte = pfn_pte(pfn, prot); - set_pte_at(mm, vaddr, ptep, pte); ptep_get_and_clear(mm, vaddr, ptep); pte = ptep_get(ptep); WARN_ON(!pte_none(pte)); @@ -101,13 +104,11 @@ static void __init pte_advanced_tests(struct mm_struct *mm, ptep_set_access_flags(vma, vaddr, ptep, pte, 1); pte = ptep_get(ptep); WARN_ON(!(pte_write(pte) && pte_dirty(pte))); - - pte = pfn_pte(pfn, prot); - set_pte_at(mm, vaddr, ptep, pte); ptep_get_and_clear_full(mm, vaddr, ptep, 1); pte = ptep_get(ptep); WARN_ON(!pte_none(pte)); + pte = pfn_pte(pfn, prot); pte = pte_mkyoung(pte); set_pte_at(mm, vaddr, ptep, pte); ptep_test_and_clear_young(vma, vaddr, ptep); @@ -169,9 +170,6 @@ static void __init pmd_advanced_tests(struct mm_struct *mm, pmdp_set_wrprotect(mm, vaddr, pmdp); pmd = READ_ONCE(*pmdp); WARN_ON(pmd_write(pmd)); - - pmd = pfn_pmd(pfn, prot); - set_pmd_at(mm, vaddr, pmdp, pmd); pmdp_huge_get_and_clear(mm, vaddr, pmdp); pmd = READ_ONCE(*pmdp); WARN_ON(!pmd_none(pmd)); @@ -185,13 +183,11 @@ static void __init pmd_advanced_tests(struct mm_struct *mm, pmdp_set_access_flags(vma, vaddr, pmdp, pmd, 1); pmd = READ_ONCE(*pmdp); WARN_ON(!(pmd_write(pmd) && pmd_dirty(pmd))); - - pmd = pmd_mkhuge(pfn_pmd(pfn, prot)); - set_pmd_at(mm, vaddr, pmdp, pmd); pmdp_huge_get_and_clear_full(vma, vaddr, pmdp, 1); pmd = READ_ONCE(*pmdp); WARN_ON(!pmd_none(pmd)); + pmd = pmd_mkhuge(pfn_pmd(pfn, prot)); pmd = pmd_mkyoung(pmd); set_pmd_at(mm, vaddr, pmdp, pmd); pmdp_test_and_clear_young(vma, vaddr, pmdp); @@ -291,17 +287,9 @@ static void __init pud_advanced_tests(struct mm_struct *mm, WARN_ON(pud_write(pud)); #ifndef __PAGETABLE_PMD_FOLDED - pud = pfn_pud(pfn, prot); - set_pud_at(mm, vaddr, pudp, pud); pudp_huge_get_and_clear(mm, vaddr, pudp); pud = READ_ONCE(*pudp); WARN_ON(!pud_none(pud)); - - pud = pfn_pud(pfn, prot); - set_pud_at(mm, vaddr, pudp, pud); - pudp_huge_get_and_clear_full(mm, vaddr, pudp, 1); - pud = READ_ONCE(*pudp); - WARN_ON(!pud_none(pud)); #endif /* __PAGETABLE_PMD_FOLDED */ pud = pfn_pud(pfn, prot); pud = pud_wrprotect(pud); @@ -313,6 +301,13 @@ static void __init pud_advanced_tests(struct mm_struct *mm, pud = READ_ONCE(*pudp); WARN_ON(!(pud_write(pud) && pud_dirty(pud))); +#ifndef __PAGETABLE_PMD_FOLDED + pudp_huge_get_and_clear_full(mm, vaddr, pudp, 1); + pud = READ_ONCE(*pudp); + WARN_ON(!pud_none(pud)); +#endif /* __PAGETABLE_PMD_FOLDED */ + + pud = pfn_pud(pfn, prot); pud = pud_mkyoung(pud); set_pud_at(mm, vaddr, pudp, pud); pudp_test_and_clear_young(vma, vaddr, pudp); -- cgit