[PATCH V2 2/3] mm/debug: Add tests validating arch advanced page table helpers

Anshuman Khandual
2020-03-24T05:23:36Z

This adds new tests validating for these following arch advanced page table
helpers. These tests create and test specific mapping types at various page
table levels.

1. pxxp_set_wrprotect()
2. pxxp_get_and_clear()
3. pxxp_set_access_flags()
4. pxxp_get_and_clear_full()
5. pxxp_test_and_clear_young()
6. pxx_leaf()
7. pxx_set_huge()
8. pxx_(clear|mk)_savedwrite()
9. huge_pxxp_xxx()

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: linux-riscv@lists.infradead.org
Cc: x86@kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
mm/debug_vm_pgtable.c | 290 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 290 insertions(+)

diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index 15055a8f6478..87b4b495333b 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -29,6 +29,7 @@
#include <linux/sched/mm.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
+#include <asm/tlbflush.h>

/*
* Basic operations
@@ -68,6 +69,54 @@ static void __init pte_basic_tests(unsigned long pfn, pgprot_t prot)
WARN_ON(pte_write(pte_wrprotect(pte_mkwrite(pte))));
}

+static void __init pte_advanced_tests(struct mm_struct *mm,
+ struct vm_area_struct *vma, pte_t *ptep,
+ unsigned long pfn, unsigned long vaddr, pgprot_t prot)
+{
+ pte_t pte = pfn_pte(pfn, prot);
+
+ pte = pfn_pte(pfn, prot);
+ set_pte_at(mm, vaddr, ptep, pte);
+ ptep_set_wrprotect(mm, vaddr, ptep);
+ pte = READ_ONCE(*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 = READ_ONCE(*ptep);
+ WARN_ON(!pte_none(pte));
+
+ pte = pfn_pte(pfn, prot);
+ pte = pte_wrprotect(pte);
+ pte = pte_mkclean(pte);
+ set_pte_at(mm, vaddr, ptep, pte);
+ pte = pte_mkwrite(pte);
+ pte = pte_mkdirty(pte);
+ ptep_set_access_flags(vma, vaddr, ptep, pte, 1);
+ pte = READ_ONCE(*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 = READ_ONCE(*ptep);
+ WARN_ON(!pte_none(pte));
+
+ pte = pte_mkyoung(pte);
+ set_pte_at(mm, vaddr, ptep, pte);
+ ptep_test_and_clear_young(vma, vaddr, ptep);
+ pte = READ_ONCE(*ptep);
+ WARN_ON(pte_young(pte));
+}
+
+static void __init pte_savedwrite_tests(unsigned long pfn, pgprot_t prot)
+{
+ pte_t pte = pfn_pte(pfn, prot);
+
+ WARN_ON(!pte_savedwrite(pte_mk_savedwrite(pte_clear_savedwrite(pte))));
+ WARN_ON(pte_savedwrite(pte_clear_savedwrite(pte_mk_savedwrite(pte))));
+}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot)
{
@@ -87,6 +136,83 @@ static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot)
WARN_ON(!pmd_bad(pmd_mkhuge(pmd)));
}

+static void __init pmd_advanced_tests(struct mm_struct *mm,
+ struct vm_area_struct *vma, pmd_t *pmdp,
+ unsigned long pfn, unsigned long vaddr, pgprot_t prot)
+{
+ pmd_t pmd = pfn_pmd(pfn, prot);
+
+ /* Align the address wrt HPAGE_PMD_SIZE */
+ vaddr = (vaddr & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE;
+
+ pmd = pfn_pmd(pfn, prot);
+ set_pmd_at(mm, vaddr, pmdp, pmd);
+ 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));
+
+ pmd = pfn_pmd(pfn, prot);
+ pmd = pmd_wrprotect(pmd);
+ pmd = pmd_mkclean(pmd);
+ set_pmd_at(mm, vaddr, pmdp, pmd);
+ pmd = pmd_mkwrite(pmd);
+ pmd = pmd_mkdirty(pmd);
+ 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(mm, vaddr, pmdp, 1);
+ pmd = READ_ONCE(*pmdp);
+ WARN_ON(!pmd_none(pmd));
+
+ pmd = pmd_mkyoung(pmd);
+ set_pmd_at(mm, vaddr, pmdp, pmd);
+ pmdp_test_and_clear_young(vma, vaddr, pmdp);
+ pmd = READ_ONCE(*pmdp);
+ WARN_ON(pmd_young(pmd));
+}
+
+static void __init pmd_leaf_tests(unsigned long pfn, pgprot_t prot)
+{
+ pmd_t pmd = pfn_pmd(pfn, prot);
+
+ /*
+ * PMD based THP is a leaf entry.
+ */
+ pmd = pmd_mkhuge(pmd);
+ WARN_ON(!pmd_leaf(pmd));
+}
+
+static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot)
+{
+ pmd_t pmd;
+
+ /*
+ * X86 defined pmd_set_huge() verifies that the given
+ * PMD is not a populated non-leaf entry.
+ */
+ WRITE_ONCE(*pmdp, __pmd(0));
+ WARN_ON(!pmd_set_huge(pmdp, __pfn_to_phys(pfn), prot));
+ WARN_ON(!pmd_clear_huge(pmdp));
+ pmd = READ_ONCE(*pmdp);
+ WARN_ON(!pmd_none(pmd));
+}
+
+static void __init pmd_savedwrite_tests(unsigned long pfn, pgprot_t prot)
+{
+ pmd_t pmd = pfn_pmd(pfn, prot);
+
+ WARN_ON(!pmd_savedwrite(pmd_mk_savedwrite(pmd_clear_savedwrite(pmd))));
+ WARN_ON(pmd_savedwrite(pmd_clear_savedwrite(pmd_mk_savedwrite(pmd))));
+}
#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot)
{
@@ -107,12 +233,110 @@ static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot)
*/
WARN_ON(!pud_bad(pud_mkhuge(pud)));
}
+
+static void pud_advanced_tests(struct mm_struct *mm,
+ struct vm_area_struct *vma, pud_t *pudp,
+ unsigned long pfn, unsigned long vaddr, pgprot_t prot)
+{
+ pud_t pud = pfn_pud(pfn, prot);
+
+ /* Align the address wrt HPAGE_PUD_SIZE */
+ vaddr = (vaddr & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE;
+
+ set_pud_at(mm, vaddr, pudp, pud);
+ pudp_set_wrprotect(mm, vaddr, pudp);
+ pud = READ_ONCE(*pudp);
+ 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
+ pud = pfn_pud(pfn, prot);
+ pud = pud_wrprotect(pud);
+ pud = pud_mkclean(pud);
+ set_pud_at(mm, vaddr, pudp, pud);
+ pud = pud_mkwrite(pud);
+ pud = pud_mkdirty(pud);
+ pudp_set_access_flags(vma, vaddr, pudp, pud, 1);
+ pud = READ_ONCE(*pudp);
+ WARN_ON(!(pud_write(pud) && pud_dirty(pud)));
+
+ pud = pud_mkyoung(pud);
+ set_pud_at(mm, vaddr, pudp, pud);
+ pudp_test_and_clear_young(vma, vaddr, pudp);
+ pud = READ_ONCE(*pudp);
+ WARN_ON(pud_young(pud));
+}
+
+static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot)
+{
+ pud_t pud = pfn_pud(pfn, prot);
+
+ /*
+ * PUD based THP is a leaf entry.
+ */
+ pud = pud_mkhuge(pud);
+ WARN_ON(!pud_leaf(pud));
+}
+
+static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
+{
+ pud_t pud;
+
+ /*
+ * X86 defined pud_set_huge() verifies that the given
+ * PUD is not a populated non-leaf entry.
+ */
+ WRITE_ONCE(*pudp, __pud(0));
+ WARN_ON(!pud_set_huge(pudp, __pfn_to_phys(pfn), prot));
+ WARN_ON(!pud_clear_huge(pudp));
+ pud = READ_ONCE(*pudp);
+ WARN_ON(!pud_none(pud));
+}
#else
static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot) { }
+static void pud_advanced_tests(struct mm_struct *mm,
+ struct vm_area_struct *vma, pud_t *pudp,
+ unsigned long pfn, unsigned long vaddr, pgprot_t prot)
+{
+}
+static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot) { }
+static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
+{
+}
#endif
#else
static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot) { }
static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot) { }
+static void __init pmd_advanced_tests(struct mm_struct *mm,
+ struct vm_area_struct *vma, pmd_t *pmdp,
+ unsigned long pfn, unsigned long vaddr, pgprot_t prot)
+{
+}
+static void __init pud_advanced_tests(struct mm_struct *mm,
+ struct vm_area_struct *vma, pud_t *pudp,
+ unsigned long pfn, unsigned long vaddr, pgprot_t prot)
+{
+}
+static void __init pmd_leaf_tests(unsigned long pfn, pgprot_t prot) { }
+static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot) { }
+static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot)
+{
+}
+static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
+{
+}
+static void __init pmd_savedwrite_tests(unsigned long pfn, pgprot_t prot) { }
#endif

static void __init p4d_basic_tests(unsigned long pfn, pgprot_t prot)
@@ -500,8 +724,52 @@ static void __init hugetlb_basic_tests(unsigned long pfn, pgprot_t prot)
WARN_ON(!pte_huge(pte_mkhuge(pte)));
#endif
}
+
+static void __init hugetlb_advanced_tests(struct mm_struct *mm,
+ struct vm_area_struct *vma,
+ pte_t *ptep, unsigned long pfn,
+ unsigned long vaddr, pgprot_t prot)
+{
+ struct page *page = pfn_to_page(pfn);
+ pte_t pte = READ_ONCE(*ptep);
+
+ pte = __pte(pte_val(pte) | RANDOM_ORVALUE);
+ set_huge_pte_at(mm, vaddr, ptep, pte);
+ barrier();
+ WARN_ON(!pte_same(pte, huge_ptep_get(ptep)));
+ huge_pte_clear(mm, vaddr, ptep, PMD_SIZE);
+ pte = READ_ONCE(*ptep);
+ WARN_ON(!huge_pte_none(pte));
+
+ pte = mk_huge_pte(page, prot);
+ set_huge_pte_at(mm, vaddr, ptep, pte);
+ huge_ptep_set_wrprotect(mm, vaddr, ptep);
+ pte = READ_ONCE(*ptep);
+ WARN_ON(huge_pte_write(pte));
+
+ pte = mk_huge_pte(page, prot);
+ set_huge_pte_at(mm, vaddr, ptep, pte);
+ huge_ptep_get_and_clear(mm, vaddr, ptep);
+ pte = READ_ONCE(*ptep);
+ WARN_ON(!huge_pte_none(pte));
+
+ pte = mk_huge_pte(page, prot);
+ pte = huge_pte_wrprotect(pte);
+ set_huge_pte_at(mm, vaddr, ptep, pte);
+ pte = huge_pte_mkwrite(pte);
+ pte = huge_pte_mkdirty(pte);
+ huge_ptep_set_access_flags(vma, vaddr, ptep, pte, 1);
+ pte = READ_ONCE(*ptep);
+ WARN_ON(!(huge_pte_write(pte) && huge_pte_dirty(pte)));
+}
#else
static void __init hugetlb_basic_tests(unsigned long pfn, pgprot_t prot) { }
+static void __init hugetlb_advanced_tests(struct mm_struct *mm,
+ struct vm_area_struct *vma,
+ pte_t *ptep, unsigned long pfn,
+ unsigned long vaddr, pgprot_t prot)
+{
+}
#endif

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
@@ -564,6 +832,7 @@ static unsigned long __init get_random_vaddr(void)

void __init debug_vm_pgtable(void)
{
+ struct vm_area_struct *vma;
struct mm_struct *mm;
pgd_t *pgdp;
p4d_t *p4dp, *saved_p4dp;
@@ -592,6 +861,12 @@ void __init debug_vm_pgtable(void)
*/
protnone = __P000;

+ vma = vm_area_alloc(mm);
+ if (!vma) {
+ pr_err("vma allocation failed\n");
+ return;
+ }
+
/*
* PFN for mapping at PTE level is determined from a standard kernel
* text symbol. But pfns for higher page table levels are derived by
@@ -640,6 +915,20 @@ void __init debug_vm_pgtable(void)
p4d_clear_tests(mm, p4dp);
pgd_clear_tests(mm, pgdp);

+ pte_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
+ pmd_advanced_tests(mm, vma, pmdp, pmd_aligned, vaddr, prot);
+ pud_advanced_tests(mm, vma, pudp, pud_aligned, vaddr, prot);
+ hugetlb_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
+
+ pmd_leaf_tests(pmd_aligned, prot);
+ pud_leaf_tests(pud_aligned, prot);
+
+ pmd_huge_tests(pmdp, pmd_aligned, prot);
+ pud_huge_tests(pudp, pud_aligned, prot);
+
+ pte_savedwrite_tests(pte_aligned, prot);
+ pmd_savedwrite_tests(pmd_aligned, prot);
+
pte_unmap_unlock(ptep, ptl);

pmd_populate_tests(mm, pmdp, saved_ptep);
@@ -674,6 +963,7 @@ void __init debug_vm_pgtable(void)
pmd_free(mm, saved_pmdp);
pte_free(mm, saved_ptep);

+ vm_area_free(vma);
mm_dec_nr_puds(mm);
mm_dec_nr_pmds(mm);
mm_dec_nr_ptes(mm);
--
2.20.1