Commit c3824e18 authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Linus Torvalds
Browse files

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: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: default avatarAnshuman Khandual <anshuman.khandual@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4200605b

mm/debug_vm_pgtable.c

+15 −20
Original line number Diff line number Diff line
@@ -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);