[PATCH v5 00/12] mm/debug_vm_pgtable: Enhancements

[PATCH v5 00/12] mm/debug_vm_pgtable: Enhancements

[Gavin Shan]

There are couple of issues with current implementations and this series
tries to resolve the issues:

  (a) All needed information are scattered in variables, passed to various
      test functions. The code is organized in pretty much relaxed fashion.

  (b) The page isn't allocated from buddy during page table entry modifying
      tests. The page can be invalid, conflicting to the implementations
      of set_xxx_at() on ARM64. The target page is accessed so that the
      iCache can be flushed when execution permission is given on ARM64.
      Besides, the target page can be unmapped and accessing to it causes
      kernel crash.

"struct pgtable_debug_args" is introduced to address issue (a). For issue
(b), the used page is allocated from buddy in page table entry modifying
tests. The corresponding tets will be skipped if we fail to allocate the
(huge) page. For other test cases, the original page around to kernel
symbol (@start_kernel) is still used.

The patches are organized as below. PATCH[2-10] could be combined to one
patch, but it will make the review harder:

  PATCH[1] introduces "struct pgtable_debug_args" as place holder of all
           needed information. With it, the old and new implementation
           can coexist.
  PATCH[2-10] uses "struct pgtable_debug_args" in various test functions.
  PATCH[11] removes the unused code for old implementation.
  PATCH[12] fixes the issue of corrupted page flag for ARM64

Changelog
=========
v5:
   * Pick r-bs from Anshuman and rebase to 5.14.rc4          (Gavin)
   * Use args->start_p4dp to free p4d entries                (Anshuman)
   * Introduce helper to allocate huge page in init_arg()    (Anshuman)
   * Bail early if the allocated page doesn't exist in
     swap_migration_tests() and correct the comments         (Anshuman)
   * Add fixes tag to PATCH[v4 12/12]                        (Christophe)
   * Address misc comments                                   (Anshuman)
v4:
   * Determine the page allocation method according to
     MAX_ORDER                                               (Anshuman)
   * Move existing comments to init_args()                   (Anshuman)
   * Code refactoring as suggested by Anshuman               (Anshuman)
   * Improved commit log and add comments for flush_dcache_page()
     in PATCH[v4 12/12]                                      (Anshuman)
   * Address misc comments                                   (Anshuman)
v3:
   * Fix the warning caused by allocating more pages than
     (1 << (MAX_ORDER - 1)) in init_args()                   (syzbot)
   * Fix build warning by dropping unused variables in separate
     patches                                                 (0-day)
   * Missed "WARN_ON(!pud_none(pud))" in pud_huge_tests() in
     PATCH[v2 09/12]                                         (0-day)
   * Fix the subjects for PATCH[05/12] and PATCH[09/12]      (Gavin)
v2:
   * Rename struct vm_pgtable_debug to struct pgtable_debug_args.
     The parameter name to various test functions are renamed
     to "@args"                                              (Anshuman)
   * Code changes as suggested by Anshuman                   (Anshuman)

Gavin Shan (12):
  mm/debug_vm_pgtable: Introduce struct pgtable_debug_args
  mm/debug_vm_pgtable: Use struct pgtable_debug_args in basic tests
  mm/debug_vm_pgtable: Use struct pgtable_debug_args in leaf and
    savewrite tests
  mm/debug_vm_pgtable: Use struct pgtable_debug_args in protnone and
    devmap tests
  mm/debug_vm_pgtable: Use struct pgtable_debug_args in soft_dirty and
    swap tests
  mm/debug_vm_pgtable: Use struct pgtable_debug_args in migration and
    thp tests
  mm/debug_vm_pgtable: Use struct pgtable_debug_args in PTE modifying
    tests
  mm/debug_vm_pgtable: Use struct pgtable_debug_args in PMD modifying
    tests
  mm/debug_vm_pgtable: Use struct pgtable_debug_args in PUD modifying
    tests
  mm/debug_vm_pgtable: Use struct pgtable_debug_args in PGD and P4D
    modifying tests
  mm/debug_vm_pgtable: Remove unused code
  mm/debug_vm_pgtable: Fix corrupted page flag

 mm/debug_vm_pgtable.c | 916 +++++++++++++++++++++++++-----------------
 1 file changed, 558 insertions(+), 358 deletions(-)

-- 
2.23.0

[PATCH v5 01/12] mm/debug_vm_pgtable: Introduce struct pgtable_debug_args

[Gavin Shan]

In debug_vm_pgtable(), there are many local variables introduced to
track the needed information and they are passed to the functions for
various test cases. It'd better to introduce a struct as place holder
for these information. With it, what the tests functions need is the
struct. In this way, the code is simplified and easier to be maintained.

Besides, set_xxx_at() could access the data on the corresponding pages
in the page table modifying tests. So the accessed pages in the tests
should have been allocated from buddy. Otherwise, we're accessing pages
that aren't owned by us. This causes issues like page flag corruption
or kernel crash on accessing unmapped page when CONFIG_DEBUG_PAGEALLOC
is enabled.

This introduces "struct pgtable_debug_args". The struct is initialized
and destroyed, but the information in the struct isn't used yet. It will
be used in subsequent patches.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 mm/debug_vm_pgtable.c | 269 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 268 insertions(+), 1 deletion(-)

diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index 1c922691aa61..6a825f0e7cd7 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -58,6 +58,37 @@
 #define RANDOM_ORVALUE (GENMASK(BITS_PER_LONG - 1, 0) & ~ARCH_SKIP_MASK)
 #define RANDOM_NZVALUE	GENMASK(7, 0)
 
+struct pgtable_debug_args {
+	struct mm_struct	*mm;
+	struct vm_area_struct	*vma;
+
+	pgd_t			*pgdp;
+	p4d_t			*p4dp;
+	pud_t			*pudp;
+	pmd_t			*pmdp;
+	pte_t			*ptep;
+
+	p4d_t			*start_p4dp;
+	pud_t			*start_pudp;
+	pmd_t			*start_pmdp;
+	pgtable_t		start_ptep;
+
+	unsigned long		vaddr;
+	pgprot_t		page_prot;
+	pgprot_t		page_prot_none;
+
+	bool			is_contiguous_page;
+	unsigned long		pud_pfn;
+	unsigned long		pmd_pfn;
+	unsigned long		pte_pfn;
+
+	unsigned long		fixed_pgd_pfn;
+	unsigned long		fixed_p4d_pfn;
+	unsigned long		fixed_pud_pfn;
+	unsigned long		fixed_pmd_pfn;
+	unsigned long		fixed_pte_pfn;
+};
+
 static void __init pte_basic_tests(unsigned long pfn, int idx)
 {
 	pgprot_t prot = protection_map[idx];
@@ -955,8 +986,238 @@ static unsigned long __init get_random_vaddr(void)
 	return random_vaddr;
 }
 
+static void __init destroy_args(struct pgtable_debug_args *args)
+{
+	struct page *page = NULL;
+
+	/* Free (huge) page */
+	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
+	    IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) &&
+	    has_transparent_hugepage() &&
+	    args->pud_pfn != ULONG_MAX) {
+		if (args->is_contiguous_page) {
+			free_contig_range(args->pud_pfn,
+					  (1 << (HPAGE_PUD_SHIFT - PAGE_SHIFT)));
+		} else {
+			page = pfn_to_page(args->pud_pfn);
+			__free_pages(page, HPAGE_PUD_SHIFT - PAGE_SHIFT);
+		}
+
+		args->pud_pfn = ULONG_MAX;
+		args->pmd_pfn = ULONG_MAX;
+		args->pte_pfn = ULONG_MAX;
+	}
+
+	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
+	    has_transparent_hugepage() &&
+	    args->pmd_pfn != ULONG_MAX) {
+		if (args->is_contiguous_page) {
+			free_contig_range(args->pmd_pfn, (1 << HPAGE_PMD_ORDER));
+		} else {
+			page = pfn_to_page(args->pmd_pfn);
+			__free_pages(page, HPAGE_PMD_ORDER);
+		}
+
+		args->pmd_pfn = ULONG_MAX;
+		args->pte_pfn = ULONG_MAX;
+	}
+
+	if (args->pte_pfn != ULONG_MAX) {
+		page = pfn_to_page(args->pte_pfn);
+		__free_pages(page, 0);
+	}
+
+	/* Free page table entries */
+	if (args->start_ptep) {
+		pte_free(args->mm, args->start_ptep);
+		mm_dec_nr_ptes(args->mm);
+	}
+
+	if (args->start_pmdp) {
+		pmd_free(args->mm, args->start_pmdp);
+		mm_dec_nr_pmds(args->mm);
+	}
+
+	if (args->start_pudp) {
+		pud_free(args->mm, args->start_pudp);
+		mm_dec_nr_puds(args->mm);
+	}
+
+	if (args->start_p4dp)
+		p4d_free(args->mm, args->start_p4dp);
+
+	/* Free vma and mm struct */
+	if (args->vma)
+		vm_area_free(args->vma);
+
+	if (args->mm)
+		mmdrop(args->mm);
+}
+
+static struct page * __init debug_vm_pgtable_alloc_huge_page(
+				struct pgtable_debug_args *args, int order)
+{
+	struct page *page = NULL;
+
+#ifdef CONFIG_CONTIG_ALLOC
+	if (order >= MAX_ORDER) {
+		page = alloc_contig_pages((1 << order), GFP_KERNEL,
+					  first_online_node, NULL);
+		if (page) {
+			args->is_contiguous_page = true;
+			return page;
+		}
+	}
+#endif
+
+	if (order < MAX_ORDER)
+		page = alloc_pages(GFP_KERNEL, order);
+
+	return page;
+}
+
+static int __init init_args(struct pgtable_debug_args *args)
+{
+	struct page *page = NULL;
+	phys_addr_t phys;
+	int ret = 0;
+
+	/*
+	 * Initialize the debugging data.
+	 *
+	 * __P000 (or even __S000) will help create page table entries with
+	 * PROT_NONE permission as required for pxx_protnone_tests().
+	 */
+	memset(args, 0, sizeof(*args));
+	args->vaddr              = get_random_vaddr();
+	args->page_prot          = vm_get_page_prot(VMFLAGS);
+	args->page_prot_none     = __P000;
+	args->is_contiguous_page = false;
+	args->pud_pfn            = ULONG_MAX;
+	args->pmd_pfn            = ULONG_MAX;
+	args->pte_pfn            = ULONG_MAX;
+	args->fixed_pgd_pfn      = ULONG_MAX;
+	args->fixed_p4d_pfn      = ULONG_MAX;
+	args->fixed_pud_pfn      = ULONG_MAX;
+	args->fixed_pmd_pfn      = ULONG_MAX;
+	args->fixed_pte_pfn      = ULONG_MAX;
+
+	/* Allocate mm and vma */
+	args->mm = mm_alloc();
+	if (!args->mm) {
+		pr_err("Failed to allocate mm struct\n");
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	args->vma = vm_area_alloc(args->mm);
+	if (!args->vma) {
+		pr_err("Failed to allocate vma\n");
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	/*
+	 * Allocate page table entries. They will be modified in the tests.
+	 * Lets save the page table entries so that they can be released
+	 * when the tests are completed.
+	 */
+	args->pgdp = pgd_offset(args->mm, args->vaddr);
+	args->p4dp = p4d_alloc(args->mm, args->pgdp, args->vaddr);
+	args->start_p4dp = p4d_offset(args->pgdp, 0UL);
+	WARN_ON(!args->start_p4dp);
+	if (!args->p4dp) {
+		pr_err("Failed to allocate p4d entries\n");
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	args->pudp = pud_alloc(args->mm, args->p4dp, args->vaddr);
+	args->start_pudp = pud_offset(args->p4dp, 0UL);
+	WARN_ON(!args->start_pudp);
+	if (!args->pudp) {
+		pr_err("Failed to allocate pud entries\n");
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	args->pmdp = pmd_alloc(args->mm, args->pudp, args->vaddr);
+	args->start_pmdp = pmd_offset(args->pudp, 0UL);
+	WARN_ON(!args->start_pmdp);
+	if (!args->pmdp) {
+		pr_err("Failed to allocate pmd entries\n");
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	args->ptep = pte_alloc_map(args->mm, args->pmdp, args->vaddr);
+	args->start_ptep = pmd_pgtable(READ_ONCE(*args->pmdp));
+	WARN_ON(!args->start_ptep);
+	if (!args->ptep) {
+		pr_err("Failed to allocate pte entries\n");
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	/*
+	 * PFN for mapping at PTE level is determined from a standard kernel
+	 * text symbol. But pfns for higher page table levels are derived by
+	 * masking lower bits of this real pfn. These derived pfns might not
+	 * exist on the platform but that does not really matter as pfn_pxx()
+	 * helpers will still create appropriate entries for the test. This
+	 * helps avoid large memory block allocations to be used for mapping
+	 * at higher page table levels in some of the tests.
+	 */
+	phys = __pa_symbol(&start_kernel);
+	args->fixed_pgd_pfn = __phys_to_pfn(phys & PGDIR_MASK);
+	args->fixed_p4d_pfn = __phys_to_pfn(phys & P4D_MASK);
+	args->fixed_pud_pfn = __phys_to_pfn(phys & PUD_MASK);
+	args->fixed_pmd_pfn = __phys_to_pfn(phys & PMD_MASK);
+	args->fixed_pte_pfn = __phys_to_pfn(phys & PAGE_MASK);
+	WARN_ON(!pfn_valid(args->fixed_pte_pfn));
+
+	/*
+	 * Allocate (huge) pages because some of the tests need to access
+	 * the data in the pages. The corresponding tests will be skipped
+	 * if we fail to allocate (huge) pages.
+	 */
+	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
+	    IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) &&
+	    has_transparent_hugepage()) {
+		page = debug_vm_pgtable_alloc_huge_page(args,
+				HPAGE_PUD_SHIFT - PAGE_SHIFT);
+		if (page) {
+			args->pud_pfn = page_to_pfn(page);
+			args->pmd_pfn = args->pud_pfn;
+			args->pte_pfn = args->pud_pfn;
+			return 0;
+		}
+	}
+
+	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
+	    has_transparent_hugepage()) {
+		page = debug_vm_pgtable_alloc_huge_page(args, HPAGE_PMD_ORDER);
+		if (page) {
+			args->pmd_pfn = page_to_pfn(page);
+			args->pte_pfn = args->pmd_pfn;
+			return 0;
+		}
+	}
+
+	page = alloc_pages(GFP_KERNEL, 0);
+	if (page)
+		args->pte_pfn = page_to_pfn(page);
+
+	return 0;
+
+error:
+	destroy_args(args);
+	return ret;
+}
+
 static int __init debug_vm_pgtable(void)
 {
+	struct pgtable_debug_args args;
 	struct vm_area_struct *vma;
 	struct mm_struct *mm;
 	pgd_t *pgdp;
@@ -970,9 +1231,13 @@ static int __init debug_vm_pgtable(void)
 	unsigned long vaddr, pte_aligned, pmd_aligned;
 	unsigned long pud_aligned, p4d_aligned, pgd_aligned;
 	spinlock_t *ptl = NULL;
-	int idx;
+	int idx, ret;
 
 	pr_info("Validating architecture page table helpers\n");
+	ret = init_args(&args);
+	if (ret)
+		return ret;
+
 	prot = vm_get_page_prot(VMFLAGS);
 	vaddr = get_random_vaddr();
 	mm = mm_alloc();
@@ -1127,6 +1392,8 @@ static int __init debug_vm_pgtable(void)
 	mm_dec_nr_pmds(mm);
 	mm_dec_nr_ptes(mm);
 	mmdrop(mm);
+
+	destroy_args(&args);
 	return 0;
 }
 late_initcall(debug_vm_pgtable);
-- 
2.23.0

[PATCH v5 02/12] mm/debug_vm_pgtable: Use struct pgtable_debug_args in basic tests

[Gavin Shan]

This uses struct pgtable_debug_args in the basic test functions. The
unused variables @pgd_aligned and @p4d_aligned in debug_vm_pgtable()
are dropped.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 mm/debug_vm_pgtable.c | 50 +++++++++++++++++++++----------------------
 1 file changed, 24 insertions(+), 26 deletions(-)

diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index 6a825f0e7cd7..318a50ca0e25 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -89,10 +89,10 @@ struct pgtable_debug_args {
 	unsigned long		fixed_pte_pfn;
 };
 
-static void __init pte_basic_tests(unsigned long pfn, int idx)
+static void __init pte_basic_tests(struct pgtable_debug_args *args, int idx)
 {
 	pgprot_t prot = protection_map[idx];
-	pte_t pte = pfn_pte(pfn, prot);
+	pte_t pte = pfn_pte(args->fixed_pte_pfn, prot);
 	unsigned long val = idx, *ptr = &val;
 
 	pr_debug("Validating PTE basic (%pGv)\n", ptr);
@@ -174,7 +174,7 @@ static void __init pte_savedwrite_tests(unsigned long pfn, pgprot_t prot)
 }
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-static void __init pmd_basic_tests(unsigned long pfn, int idx)
+static void __init pmd_basic_tests(struct pgtable_debug_args *args, int idx)
 {
 	pgprot_t prot = protection_map[idx];
 	unsigned long val = idx, *ptr = &val;
@@ -184,7 +184,7 @@ static void __init pmd_basic_tests(unsigned long pfn, int idx)
 		return;
 
 	pr_debug("Validating PMD basic (%pGv)\n", ptr);
-	pmd = pfn_pmd(pfn, prot);
+	pmd = pfn_pmd(args->fixed_pmd_pfn, prot);
 
 	/*
 	 * This test needs to be executed after the given page table entry
@@ -296,7 +296,7 @@ static void __init pmd_savedwrite_tests(unsigned long pfn, pgprot_t prot)
 }
 
 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
-static void __init pud_basic_tests(struct mm_struct *mm, unsigned long pfn, int idx)
+static void __init pud_basic_tests(struct pgtable_debug_args *args, int idx)
 {
 	pgprot_t prot = protection_map[idx];
 	unsigned long val = idx, *ptr = &val;
@@ -306,7 +306,7 @@ static void __init pud_basic_tests(struct mm_struct *mm, unsigned long pfn, int
 		return;
 
 	pr_debug("Validating PUD basic (%pGv)\n", ptr);
-	pud = pfn_pud(pfn, prot);
+	pud = pfn_pud(args->fixed_pud_pfn, prot);
 
 	/*
 	 * This test needs to be executed after the given page table entry
@@ -327,7 +327,7 @@ static void __init pud_basic_tests(struct mm_struct *mm, unsigned long pfn, int
 	WARN_ON(pud_dirty(pud_wrprotect(pud_mkclean(pud))));
 	WARN_ON(!pud_dirty(pud_wrprotect(pud_mkdirty(pud))));
 
-	if (mm_pmd_folded(mm))
+	if (mm_pmd_folded(args->mm))
 		return;
 
 	/*
@@ -404,7 +404,7 @@ static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot)
 	WARN_ON(!pud_leaf(pud));
 }
 #else  /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
-static void __init pud_basic_tests(struct mm_struct *mm, unsigned long pfn, int idx) { }
+static void __init pud_basic_tests(struct pgtable_debug_args *args, int idx) { }
 static void __init pud_advanced_tests(struct mm_struct *mm,
 				      struct vm_area_struct *vma, pud_t *pudp,
 				      unsigned long pfn, unsigned long vaddr,
@@ -414,8 +414,8 @@ static void __init pud_advanced_tests(struct mm_struct *mm,
 static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot) { }
 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 #else  /* !CONFIG_TRANSPARENT_HUGEPAGE */
-static void __init pmd_basic_tests(unsigned long pfn, int idx) { }
-static void __init pud_basic_tests(struct mm_struct *mm, unsigned long pfn, int idx) { }
+static void __init pmd_basic_tests(struct pgtable_debug_args *args, int idx) { }
+static void __init pud_basic_tests(struct pgtable_debug_args *args, int idx) { }
 static void __init pmd_advanced_tests(struct mm_struct *mm,
 				      struct vm_area_struct *vma, pmd_t *pmdp,
 				      unsigned long pfn, unsigned long vaddr,
@@ -476,7 +476,7 @@ 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) { }
 #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
 
-static void __init p4d_basic_tests(unsigned long pfn, pgprot_t prot)
+static void __init p4d_basic_tests(struct pgtable_debug_args *args)
 {
 	p4d_t p4d;
 
@@ -485,7 +485,7 @@ static void __init p4d_basic_tests(unsigned long pfn, pgprot_t prot)
 	WARN_ON(!p4d_same(p4d, p4d));
 }
 
-static void __init pgd_basic_tests(unsigned long pfn, pgprot_t prot)
+static void __init pgd_basic_tests(struct pgtable_debug_args *args)
 {
 	pgd_t pgd;
 
@@ -890,7 +890,7 @@ static void __init swap_migration_tests(void)
 }
 
 #ifdef CONFIG_HUGETLB_PAGE
-static void __init hugetlb_basic_tests(unsigned long pfn, pgprot_t prot)
+static void __init hugetlb_basic_tests(struct pgtable_debug_args *args)
 {
 	struct page *page;
 	pte_t pte;
@@ -900,21 +900,21 @@ static void __init hugetlb_basic_tests(unsigned long pfn, pgprot_t prot)
 	 * Accessing the page associated with the pfn is safe here,
 	 * as it was previously derived from a real kernel symbol.
 	 */
-	page = pfn_to_page(pfn);
-	pte = mk_huge_pte(page, prot);
+	page = pfn_to_page(args->fixed_pmd_pfn);
+	pte = mk_huge_pte(page, args->page_prot);
 
 	WARN_ON(!huge_pte_dirty(huge_pte_mkdirty(pte)));
 	WARN_ON(!huge_pte_write(huge_pte_mkwrite(huge_pte_wrprotect(pte))));
 	WARN_ON(huge_pte_write(huge_pte_wrprotect(huge_pte_mkwrite(pte))));
 
 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
-	pte = pfn_pte(pfn, prot);
+	pte = pfn_pte(args->fixed_pmd_pfn, args->page_prot);
 
 	WARN_ON(!pte_huge(pte_mkhuge(pte)));
 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
 }
 #else  /* !CONFIG_HUGETLB_PAGE */
-static void __init hugetlb_basic_tests(unsigned long pfn, pgprot_t prot) { }
+static void __init hugetlb_basic_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_HUGETLB_PAGE */
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
@@ -1229,7 +1229,7 @@ static int __init debug_vm_pgtable(void)
 	pgprot_t prot, protnone;
 	phys_addr_t paddr;
 	unsigned long vaddr, pte_aligned, pmd_aligned;
-	unsigned long pud_aligned, p4d_aligned, pgd_aligned;
+	unsigned long pud_aligned;
 	spinlock_t *ptl = NULL;
 	int idx, ret;
 
@@ -1272,8 +1272,6 @@ static int __init debug_vm_pgtable(void)
 	pte_aligned = (paddr & PAGE_MASK) >> PAGE_SHIFT;
 	pmd_aligned = (paddr & PMD_MASK) >> PAGE_SHIFT;
 	pud_aligned = (paddr & PUD_MASK) >> PAGE_SHIFT;
-	p4d_aligned = (paddr & P4D_MASK) >> PAGE_SHIFT;
-	pgd_aligned = (paddr & PGDIR_MASK) >> PAGE_SHIFT;
 	WARN_ON(!pfn_valid(pte_aligned));
 
 	pgdp = pgd_offset(mm, vaddr);
@@ -1307,9 +1305,9 @@ static int __init debug_vm_pgtable(void)
 	 * given page table entry.
 	 */
 	for (idx = 0; idx < ARRAY_SIZE(protection_map); idx++) {
-		pte_basic_tests(pte_aligned, idx);
-		pmd_basic_tests(pmd_aligned, idx);
-		pud_basic_tests(mm, pud_aligned, idx);
+		pte_basic_tests(&args, idx);
+		pmd_basic_tests(&args, idx);
+		pud_basic_tests(&args, idx);
 	}
 
 	/*
@@ -1319,8 +1317,8 @@ static int __init debug_vm_pgtable(void)
 	 * the above iteration for now to save some test execution
 	 * time.
 	 */
-	p4d_basic_tests(p4d_aligned, prot);
-	pgd_basic_tests(pgd_aligned, prot);
+	p4d_basic_tests(&args);
+	pgd_basic_tests(&args);
 
 	pmd_leaf_tests(pmd_aligned, prot);
 	pud_leaf_tests(pud_aligned, prot);
@@ -1349,7 +1347,7 @@ static int __init debug_vm_pgtable(void)
 	pmd_thp_tests(pmd_aligned, prot);
 	pud_thp_tests(pud_aligned, prot);
 
-	hugetlb_basic_tests(pte_aligned, prot);
+	hugetlb_basic_tests(&args);
 
 	/*
 	 * Page table modifying tests. They need to hold
-- 
2.23.0

[PATCH v5 03/12] mm/debug_vm_pgtable: Use struct pgtable_debug_args in leaf and savewrite tests

[Gavin Shan]

This uses struct pgtable_debug_args in the leaf and savewrite test
functions.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 mm/debug_vm_pgtable.c | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index 318a50ca0e25..810f0a7a52a3 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -161,9 +161,9 @@ static void __init pte_advanced_tests(struct mm_struct *mm,
 	WARN_ON(pte_young(pte));
 }
 
-static void __init pte_savedwrite_tests(unsigned long pfn, pgprot_t prot)
+static void __init pte_savedwrite_tests(struct pgtable_debug_args *args)
 {
-	pte_t pte = pfn_pte(pfn, prot);
+	pte_t pte = pfn_pte(args->fixed_pte_pfn, args->page_prot_none);
 
 	if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
 		return;
@@ -262,7 +262,7 @@ static void __init pmd_advanced_tests(struct mm_struct *mm,
 	pgtable = pgtable_trans_huge_withdraw(mm, pmdp);
 }
 
-static void __init pmd_leaf_tests(unsigned long pfn, pgprot_t prot)
+static void __init pmd_leaf_tests(struct pgtable_debug_args *args)
 {
 	pmd_t pmd;
 
@@ -270,7 +270,7 @@ static void __init pmd_leaf_tests(unsigned long pfn, pgprot_t prot)
 		return;
 
 	pr_debug("Validating PMD leaf\n");
-	pmd = pfn_pmd(pfn, prot);
+	pmd = pfn_pmd(args->fixed_pmd_pfn, args->page_prot);
 
 	/*
 	 * PMD based THP is a leaf entry.
@@ -279,7 +279,7 @@ static void __init pmd_leaf_tests(unsigned long pfn, pgprot_t prot)
 	WARN_ON(!pmd_leaf(pmd));
 }
 
-static void __init pmd_savedwrite_tests(unsigned long pfn, pgprot_t prot)
+static void __init pmd_savedwrite_tests(struct pgtable_debug_args *args)
 {
 	pmd_t pmd;
 
@@ -290,7 +290,7 @@ static void __init pmd_savedwrite_tests(unsigned long pfn, pgprot_t prot)
 		return;
 
 	pr_debug("Validating PMD saved write\n");
-	pmd = pfn_pmd(pfn, prot);
+	pmd = pfn_pmd(args->fixed_pmd_pfn, args->page_prot_none);
 	WARN_ON(!pmd_savedwrite(pmd_mk_savedwrite(pmd_clear_savedwrite(pmd))));
 	WARN_ON(pmd_savedwrite(pmd_clear_savedwrite(pmd_mk_savedwrite(pmd))));
 }
@@ -388,7 +388,7 @@ static void __init pud_advanced_tests(struct mm_struct *mm,
 	pudp_huge_get_and_clear(mm, vaddr, pudp);
 }
 
-static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot)
+static void __init pud_leaf_tests(struct pgtable_debug_args *args)
 {
 	pud_t pud;
 
@@ -396,7 +396,7 @@ static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot)
 		return;
 
 	pr_debug("Validating PUD leaf\n");
-	pud = pfn_pud(pfn, prot);
+	pud = pfn_pud(args->fixed_pud_pfn, args->page_prot);
 	/*
 	 * PUD based THP is a leaf entry.
 	 */
@@ -411,7 +411,7 @@ static void __init pud_advanced_tests(struct mm_struct *mm,
 				      pgprot_t prot)
 {
 }
-static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot) { }
+static void __init pud_leaf_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 #else  /* !CONFIG_TRANSPARENT_HUGEPAGE */
 static void __init pmd_basic_tests(struct pgtable_debug_args *args, int idx) { }
@@ -428,9 +428,9 @@ static void __init pud_advanced_tests(struct mm_struct *mm,
 				      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_savedwrite_tests(unsigned long pfn, pgprot_t prot) { }
+static void __init pmd_leaf_tests(struct pgtable_debug_args *args) { }
+static void __init pud_leaf_tests(struct pgtable_debug_args *args) { }
+static void __init pmd_savedwrite_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
@@ -1320,11 +1320,11 @@ static int __init debug_vm_pgtable(void)
 	p4d_basic_tests(&args);
 	pgd_basic_tests(&args);
 
-	pmd_leaf_tests(pmd_aligned, prot);
-	pud_leaf_tests(pud_aligned, prot);
+	pmd_leaf_tests(&args);
+	pud_leaf_tests(&args);
 
-	pte_savedwrite_tests(pte_aligned, protnone);
-	pmd_savedwrite_tests(pmd_aligned, protnone);
+	pte_savedwrite_tests(&args);
+	pmd_savedwrite_tests(&args);
 
 	pte_special_tests(pte_aligned, prot);
 	pte_protnone_tests(pte_aligned, protnone);
-- 
2.23.0

[PATCH v5 04/12] mm/debug_vm_pgtable: Use struct pgtable_debug_args in protnone and devmap tests

[Gavin Shan]

This uses struct pgtable_debug_args in protnone and devmap test
functions. After that, the unused variable @protnone in debug_vm_pgtable()
is dropped.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 mm/debug_vm_pgtable.c | 58 +++++++++++++++++++------------------------
 1 file changed, 26 insertions(+), 32 deletions(-)

diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index 810f0a7a52a3..6630669ed9a2 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -662,9 +662,9 @@ static void __init pmd_populate_tests(struct mm_struct *mm, pmd_t *pmdp,
 	WARN_ON(pmd_bad(pmd));
 }
 
-static void __init pte_special_tests(unsigned long pfn, pgprot_t prot)
+static void __init pte_special_tests(struct pgtable_debug_args *args)
 {
-	pte_t pte = pfn_pte(pfn, prot);
+	pte_t pte = pfn_pte(args->fixed_pte_pfn, args->page_prot);
 
 	if (!IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL))
 		return;
@@ -673,9 +673,9 @@ static void __init pte_special_tests(unsigned long pfn, pgprot_t prot)
 	WARN_ON(!pte_special(pte_mkspecial(pte)));
 }
 
-static void __init pte_protnone_tests(unsigned long pfn, pgprot_t prot)
+static void __init pte_protnone_tests(struct pgtable_debug_args *args)
 {
-	pte_t pte = pfn_pte(pfn, prot);
+	pte_t pte = pfn_pte(args->fixed_pte_pfn, args->page_prot_none);
 
 	if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
 		return;
@@ -686,7 +686,7 @@ static void __init pte_protnone_tests(unsigned long pfn, pgprot_t prot)
 }
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-static void __init pmd_protnone_tests(unsigned long pfn, pgprot_t prot)
+static void __init pmd_protnone_tests(struct pgtable_debug_args *args)
 {
 	pmd_t pmd;
 
@@ -697,25 +697,25 @@ static void __init pmd_protnone_tests(unsigned long pfn, pgprot_t prot)
 		return;
 
 	pr_debug("Validating PMD protnone\n");
-	pmd = pmd_mkhuge(pfn_pmd(pfn, prot));
+	pmd = pmd_mkhuge(pfn_pmd(args->fixed_pmd_pfn, args->page_prot_none));
 	WARN_ON(!pmd_protnone(pmd));
 	WARN_ON(!pmd_present(pmd));
 }
 #else  /* !CONFIG_TRANSPARENT_HUGEPAGE */
-static void __init pmd_protnone_tests(unsigned long pfn, pgprot_t prot) { }
+static void __init pmd_protnone_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
 #ifdef CONFIG_ARCH_HAS_PTE_DEVMAP
-static void __init pte_devmap_tests(unsigned long pfn, pgprot_t prot)
+static void __init pte_devmap_tests(struct pgtable_debug_args *args)
 {
-	pte_t pte = pfn_pte(pfn, prot);
+	pte_t pte = pfn_pte(args->fixed_pte_pfn, args->page_prot);
 
 	pr_debug("Validating PTE devmap\n");
 	WARN_ON(!pte_devmap(pte_mkdevmap(pte)));
 }
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-static void __init pmd_devmap_tests(unsigned long pfn, pgprot_t prot)
+static void __init pmd_devmap_tests(struct pgtable_debug_args *args)
 {
 	pmd_t pmd;
 
@@ -723,12 +723,12 @@ static void __init pmd_devmap_tests(unsigned long pfn, pgprot_t prot)
 		return;
 
 	pr_debug("Validating PMD devmap\n");
-	pmd = pfn_pmd(pfn, prot);
+	pmd = pfn_pmd(args->fixed_pmd_pfn, args->page_prot);
 	WARN_ON(!pmd_devmap(pmd_mkdevmap(pmd)));
 }
 
 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
-static void __init pud_devmap_tests(unsigned long pfn, pgprot_t prot)
+static void __init pud_devmap_tests(struct pgtable_debug_args *args)
 {
 	pud_t pud;
 
@@ -736,20 +736,20 @@ static void __init pud_devmap_tests(unsigned long pfn, pgprot_t prot)
 		return;
 
 	pr_debug("Validating PUD devmap\n");
-	pud = pfn_pud(pfn, prot);
+	pud = pfn_pud(args->fixed_pud_pfn, args->page_prot);
 	WARN_ON(!pud_devmap(pud_mkdevmap(pud)));
 }
 #else  /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
-static void __init pud_devmap_tests(unsigned long pfn, pgprot_t prot) { }
+static void __init pud_devmap_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 #else  /* CONFIG_TRANSPARENT_HUGEPAGE */
-static void __init pmd_devmap_tests(unsigned long pfn, pgprot_t prot) { }
-static void __init pud_devmap_tests(unsigned long pfn, pgprot_t prot) { }
+static void __init pmd_devmap_tests(struct pgtable_debug_args *args) { }
+static void __init pud_devmap_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #else
-static void __init pte_devmap_tests(unsigned long pfn, pgprot_t prot) { }
-static void __init pmd_devmap_tests(unsigned long pfn, pgprot_t prot) { }
-static void __init pud_devmap_tests(unsigned long pfn, pgprot_t prot) { }
+static void __init pte_devmap_tests(struct pgtable_debug_args *args) { }
+static void __init pmd_devmap_tests(struct pgtable_debug_args *args) { }
+static void __init pud_devmap_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_ARCH_HAS_PTE_DEVMAP */
 
 static void __init pte_soft_dirty_tests(unsigned long pfn, pgprot_t prot)
@@ -1226,7 +1226,7 @@ static int __init debug_vm_pgtable(void)
 	pmd_t *pmdp, *saved_pmdp, pmd;
 	pte_t *ptep;
 	pgtable_t saved_ptep;
-	pgprot_t prot, protnone;
+	pgprot_t prot;
 	phys_addr_t paddr;
 	unsigned long vaddr, pte_aligned, pmd_aligned;
 	unsigned long pud_aligned;
@@ -1246,12 +1246,6 @@ static int __init debug_vm_pgtable(void)
 		return 1;
 	}
 
-	/*
-	 * __P000 (or even __S000) will help create page table entries with
-	 * PROT_NONE permission as required for pxx_protnone_tests().
-	 */
-	protnone = __P000;
-
 	vma = vm_area_alloc(mm);
 	if (!vma) {
 		pr_err("vma allocation failed\n");
@@ -1326,13 +1320,13 @@ static int __init debug_vm_pgtable(void)
 	pte_savedwrite_tests(&args);
 	pmd_savedwrite_tests(&args);
 
-	pte_special_tests(pte_aligned, prot);
-	pte_protnone_tests(pte_aligned, protnone);
-	pmd_protnone_tests(pmd_aligned, protnone);
+	pte_special_tests(&args);
+	pte_protnone_tests(&args);
+	pmd_protnone_tests(&args);
 
-	pte_devmap_tests(pte_aligned, prot);
-	pmd_devmap_tests(pmd_aligned, prot);
-	pud_devmap_tests(pud_aligned, prot);
+	pte_devmap_tests(&args);
+	pmd_devmap_tests(&args);
+	pud_devmap_tests(&args);
 
 	pte_soft_dirty_tests(pte_aligned, prot);
 	pmd_soft_dirty_tests(pmd_aligned, prot);
-- 
2.23.0

[PATCH v5 05/12] mm/debug_vm_pgtable: Use struct pgtable_debug_args in soft_dirty and swap tests

[Gavin Shan]

This uses struct pgtable_debug_args in the soft_dirty and swap test
functions.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 mm/debug_vm_pgtable.c | 48 +++++++++++++++++++++----------------------
 1 file changed, 23 insertions(+), 25 deletions(-)

diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index 6630669ed9a2..f25e568628d3 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -752,9 +752,9 @@ static void __init pmd_devmap_tests(struct pgtable_debug_args *args) { }
 static void __init pud_devmap_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_ARCH_HAS_PTE_DEVMAP */
 
-static void __init pte_soft_dirty_tests(unsigned long pfn, pgprot_t prot)
+static void __init pte_soft_dirty_tests(struct pgtable_debug_args *args)
 {
-	pte_t pte = pfn_pte(pfn, prot);
+	pte_t pte = pfn_pte(args->fixed_pte_pfn, args->page_prot);
 
 	if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY))
 		return;
@@ -764,9 +764,9 @@ static void __init pte_soft_dirty_tests(unsigned long pfn, pgprot_t prot)
 	WARN_ON(pte_soft_dirty(pte_clear_soft_dirty(pte)));
 }
 
-static void __init pte_swap_soft_dirty_tests(unsigned long pfn, pgprot_t prot)
+static void __init pte_swap_soft_dirty_tests(struct pgtable_debug_args *args)
 {
-	pte_t pte = pfn_pte(pfn, prot);
+	pte_t pte = pfn_pte(args->fixed_pte_pfn, args->page_prot);
 
 	if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY))
 		return;
@@ -777,7 +777,7 @@ static void __init pte_swap_soft_dirty_tests(unsigned long pfn, pgprot_t prot)
 }
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-static void __init pmd_soft_dirty_tests(unsigned long pfn, pgprot_t prot)
+static void __init pmd_soft_dirty_tests(struct pgtable_debug_args *args)
 {
 	pmd_t pmd;
 
@@ -788,12 +788,12 @@ static void __init pmd_soft_dirty_tests(unsigned long pfn, pgprot_t prot)
 		return;
 
 	pr_debug("Validating PMD soft dirty\n");
-	pmd = pfn_pmd(pfn, prot);
+	pmd = pfn_pmd(args->fixed_pmd_pfn, args->page_prot);
 	WARN_ON(!pmd_soft_dirty(pmd_mksoft_dirty(pmd)));
 	WARN_ON(pmd_soft_dirty(pmd_clear_soft_dirty(pmd)));
 }
 
-static void __init pmd_swap_soft_dirty_tests(unsigned long pfn, pgprot_t prot)
+static void __init pmd_swap_soft_dirty_tests(struct pgtable_debug_args *args)
 {
 	pmd_t pmd;
 
@@ -805,31 +805,29 @@ static void __init pmd_swap_soft_dirty_tests(unsigned long pfn, pgprot_t prot)
 		return;
 
 	pr_debug("Validating PMD swap soft dirty\n");
-	pmd = pfn_pmd(pfn, prot);
+	pmd = pfn_pmd(args->fixed_pmd_pfn, args->page_prot);
 	WARN_ON(!pmd_swp_soft_dirty(pmd_swp_mksoft_dirty(pmd)));
 	WARN_ON(pmd_swp_soft_dirty(pmd_swp_clear_soft_dirty(pmd)));
 }
 #else  /* !CONFIG_TRANSPARENT_HUGEPAGE */
-static void __init pmd_soft_dirty_tests(unsigned long pfn, pgprot_t prot) { }
-static void __init pmd_swap_soft_dirty_tests(unsigned long pfn, pgprot_t prot)
-{
-}
+static void __init pmd_soft_dirty_tests(struct pgtable_debug_args *args) { }
+static void __init pmd_swap_soft_dirty_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
-static void __init pte_swap_tests(unsigned long pfn, pgprot_t prot)
+static void __init pte_swap_tests(struct pgtable_debug_args *args)
 {
 	swp_entry_t swp;
 	pte_t pte;
 
 	pr_debug("Validating PTE swap\n");
-	pte = pfn_pte(pfn, prot);
+	pte = pfn_pte(args->fixed_pte_pfn, args->page_prot);
 	swp = __pte_to_swp_entry(pte);
 	pte = __swp_entry_to_pte(swp);
-	WARN_ON(pfn != pte_pfn(pte));
+	WARN_ON(args->fixed_pte_pfn != pte_pfn(pte));
 }
 
 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
-static void __init pmd_swap_tests(unsigned long pfn, pgprot_t prot)
+static void __init pmd_swap_tests(struct pgtable_debug_args *args)
 {
 	swp_entry_t swp;
 	pmd_t pmd;
@@ -838,13 +836,13 @@ static void __init pmd_swap_tests(unsigned long pfn, pgprot_t prot)
 		return;
 
 	pr_debug("Validating PMD swap\n");
-	pmd = pfn_pmd(pfn, prot);
+	pmd = pfn_pmd(args->fixed_pmd_pfn, args->page_prot);
 	swp = __pmd_to_swp_entry(pmd);
 	pmd = __swp_entry_to_pmd(swp);
-	WARN_ON(pfn != pmd_pfn(pmd));
+	WARN_ON(args->fixed_pmd_pfn != pmd_pfn(pmd));
 }
 #else  /* !CONFIG_ARCH_ENABLE_THP_MIGRATION */
-static void __init pmd_swap_tests(unsigned long pfn, pgprot_t prot) { }
+static void __init pmd_swap_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_ARCH_ENABLE_THP_MIGRATION */
 
 static void __init swap_migration_tests(void)
@@ -1328,13 +1326,13 @@ static int __init debug_vm_pgtable(void)
 	pmd_devmap_tests(&args);
 	pud_devmap_tests(&args);
 
-	pte_soft_dirty_tests(pte_aligned, prot);
-	pmd_soft_dirty_tests(pmd_aligned, prot);
-	pte_swap_soft_dirty_tests(pte_aligned, prot);
-	pmd_swap_soft_dirty_tests(pmd_aligned, prot);
+	pte_soft_dirty_tests(&args);
+	pmd_soft_dirty_tests(&args);
+	pte_swap_soft_dirty_tests(&args);
+	pmd_swap_soft_dirty_tests(&args);
 
-	pte_swap_tests(pte_aligned, prot);
-	pmd_swap_tests(pmd_aligned, prot);
+	pte_swap_tests(&args);
+	pmd_swap_tests(&args);
 
 	swap_migration_tests();
 
-- 
2.23.0

[PATCH v5 06/12] mm/debug_vm_pgtable: Use struct pgtable_debug_args in migration and thp tests

[Gavin Shan]

This uses struct pgtable_debug_args in the migration and thp test
functions. It's notable that the pre-allocated page is used in
swap_migration_tests() as set_pte_at() is used there.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 mm/debug_vm_pgtable.c | 36 +++++++++++++++++-------------------
 1 file changed, 17 insertions(+), 19 deletions(-)

diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index f25e568628d3..05d7f6308d6c 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -845,7 +845,7 @@ static void __init pmd_swap_tests(struct pgtable_debug_args *args)
 static void __init pmd_swap_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_ARCH_ENABLE_THP_MIGRATION */
 
-static void __init swap_migration_tests(void)
+static void __init swap_migration_tests(struct pgtable_debug_args *args)
 {
 	struct page *page;
 	swp_entry_t swp;
@@ -853,19 +853,18 @@ static void __init swap_migration_tests(void)
 	if (!IS_ENABLED(CONFIG_MIGRATION))
 		return;
 
-	pr_debug("Validating swap migration\n");
 	/*
 	 * swap_migration_tests() requires a dedicated page as it needs to
 	 * be locked before creating a migration entry from it. Locking the
 	 * page that actually maps kernel text ('start_kernel') can be real
-	 * problematic. Lets allocate a dedicated page explicitly for this
-	 * purpose that will be freed subsequently.
+	 * problematic. Lets use the allocated page explicitly for this
+	 * purpose.
 	 */
-	page = alloc_page(GFP_KERNEL);
-	if (!page) {
-		pr_err("page allocation failed\n");
+	page = (args->pte_pfn != ULONG_MAX) ? pfn_to_page(args->pte_pfn) : NULL;
+	if (!page)
 		return;
-	}
+
+	pr_debug("Validating swap migration\n");
 
 	/*
 	 * make_migration_entry() expects given page to be
@@ -884,7 +883,6 @@ static void __init swap_migration_tests(void)
 	WARN_ON(!is_migration_entry(swp));
 	WARN_ON(is_writable_migration_entry(swp));
 	__ClearPageLocked(page);
-	__free_page(page);
 }
 
 #ifdef CONFIG_HUGETLB_PAGE
@@ -916,7 +914,7 @@ static void __init hugetlb_basic_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_HUGETLB_PAGE */
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-static void __init pmd_thp_tests(unsigned long pfn, pgprot_t prot)
+static void __init pmd_thp_tests(struct pgtable_debug_args *args)
 {
 	pmd_t pmd;
 
@@ -935,7 +933,7 @@ static void __init pmd_thp_tests(unsigned long pfn, pgprot_t prot)
 	 * needs to return true. pmd_present() should be true whenever
 	 * pmd_trans_huge() returns true.
 	 */
-	pmd = pfn_pmd(pfn, prot);
+	pmd = pfn_pmd(args->fixed_pmd_pfn, args->page_prot);
 	WARN_ON(!pmd_trans_huge(pmd_mkhuge(pmd)));
 
 #ifndef __HAVE_ARCH_PMDP_INVALIDATE
@@ -945,7 +943,7 @@ static void __init pmd_thp_tests(unsigned long pfn, pgprot_t prot)
 }
 
 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
-static void __init pud_thp_tests(unsigned long pfn, pgprot_t prot)
+static void __init pud_thp_tests(struct pgtable_debug_args *args)
 {
 	pud_t pud;
 
@@ -953,7 +951,7 @@ static void __init pud_thp_tests(unsigned long pfn, pgprot_t prot)
 		return;
 
 	pr_debug("Validating PUD based THP\n");
-	pud = pfn_pud(pfn, prot);
+	pud = pfn_pud(args->fixed_pud_pfn, args->page_prot);
 	WARN_ON(!pud_trans_huge(pud_mkhuge(pud)));
 
 	/*
@@ -965,11 +963,11 @@ static void __init pud_thp_tests(unsigned long pfn, pgprot_t prot)
 	 */
 }
 #else  /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
-static void __init pud_thp_tests(unsigned long pfn, pgprot_t prot) { }
+static void __init pud_thp_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 #else  /* !CONFIG_TRANSPARENT_HUGEPAGE */
-static void __init pmd_thp_tests(unsigned long pfn, pgprot_t prot) { }
-static void __init pud_thp_tests(unsigned long pfn, pgprot_t prot) { }
+static void __init pmd_thp_tests(struct pgtable_debug_args *args) { }
+static void __init pud_thp_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
 static unsigned long __init get_random_vaddr(void)
@@ -1334,10 +1332,10 @@ static int __init debug_vm_pgtable(void)
 	pte_swap_tests(&args);
 	pmd_swap_tests(&args);
 
-	swap_migration_tests();
+	swap_migration_tests(&args);
 
-	pmd_thp_tests(pmd_aligned, prot);
-	pud_thp_tests(pud_aligned, prot);
+	pmd_thp_tests(&args);
+	pud_thp_tests(&args);
 
 	hugetlb_basic_tests(&args);
 
-- 
2.23.0

[PATCH v5 07/12] mm/debug_vm_pgtable: Use struct pgtable_debug_args in PTE modifying tests

[Gavin Shan]

This uses struct pgtable_debug_args in PTE modifying tests. The allocated
page is used as set_pte_at() is used there. The tests are skipped if
the allocated page doesn't exist. Besides, the unused variable @pte_aligned
in debug_vm_pgtable() are dropped.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 mm/debug_vm_pgtable.c | 64 +++++++++++++++++++++----------------------
 1 file changed, 31 insertions(+), 33 deletions(-)

diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index 05d7f6308d6c..a9beac0b6ce0 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -117,10 +117,7 @@ static void __init pte_basic_tests(struct pgtable_debug_args *args, int idx)
 	WARN_ON(!pte_dirty(pte_wrprotect(pte_mkdirty(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)
+static void __init pte_advanced_tests(struct pgtable_debug_args *args)
 {
 	pte_t pte;
 
@@ -129,35 +126,37 @@ static void __init pte_advanced_tests(struct mm_struct *mm,
 	 * This requires set_pte_at to be not used to update an
 	 * existing pte entry. Clear pte before we do set_pte_at
 	 */
+	if (args->pte_pfn == ULONG_MAX)
+		return;
 
 	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);
+	pte = pfn_pte(args->pte_pfn, args->page_prot);
+	set_pte_at(args->mm, args->vaddr, args->ptep, pte);
+	ptep_set_wrprotect(args->mm, args->vaddr, args->ptep);
+	pte = ptep_get(args->ptep);
 	WARN_ON(pte_write(pte));
-	ptep_get_and_clear(mm, vaddr, ptep);
-	pte = ptep_get(ptep);
+	ptep_get_and_clear(args->mm, args->vaddr, args->ptep);
+	pte = ptep_get(args->ptep);
 	WARN_ON(!pte_none(pte));
 
-	pte = pfn_pte(pfn, prot);
+	pte = pfn_pte(args->pte_pfn, args->page_prot);
 	pte = pte_wrprotect(pte);
 	pte = pte_mkclean(pte);
-	set_pte_at(mm, vaddr, ptep, pte);
+	set_pte_at(args->mm, args->vaddr, args->ptep, pte);
 	pte = pte_mkwrite(pte);
 	pte = pte_mkdirty(pte);
-	ptep_set_access_flags(vma, vaddr, ptep, pte, 1);
-	pte = ptep_get(ptep);
+	ptep_set_access_flags(args->vma, args->vaddr, args->ptep, pte, 1);
+	pte = ptep_get(args->ptep);
 	WARN_ON(!(pte_write(pte) && pte_dirty(pte)));
-	ptep_get_and_clear_full(mm, vaddr, ptep, 1);
-	pte = ptep_get(ptep);
+	ptep_get_and_clear_full(args->mm, args->vaddr, args->ptep, 1);
+	pte = ptep_get(args->ptep);
 	WARN_ON(!pte_none(pte));
 
-	pte = pfn_pte(pfn, prot);
+	pte = pfn_pte(args->pte_pfn, args->page_prot);
 	pte = pte_mkyoung(pte);
-	set_pte_at(mm, vaddr, ptep, pte);
-	ptep_test_and_clear_young(vma, vaddr, ptep);
-	pte = ptep_get(ptep);
+	set_pte_at(args->mm, args->vaddr, args->ptep, pte);
+	ptep_test_and_clear_young(args->vma, args->vaddr, args->ptep);
+	pte = ptep_get(args->ptep);
 	WARN_ON(pte_young(pte));
 }
 
@@ -618,20 +617,21 @@ static void __init pgd_populate_tests(struct mm_struct *mm, pgd_t *pgdp,
 }
 #endif /* PAGETABLE_P4D_FOLDED */
 
-static void __init pte_clear_tests(struct mm_struct *mm, pte_t *ptep,
-				   unsigned long pfn, unsigned long vaddr,
-				   pgprot_t prot)
+static void __init pte_clear_tests(struct pgtable_debug_args *args)
 {
-	pte_t pte = pfn_pte(pfn, prot);
+	pte_t pte = pfn_pte(args->pte_pfn, args->page_prot);
+
+	if (args->pte_pfn == ULONG_MAX)
+		return;
 
 	pr_debug("Validating PTE clear\n");
 #ifndef CONFIG_RISCV
 	pte = __pte(pte_val(pte) | RANDOM_ORVALUE);
 #endif
-	set_pte_at(mm, vaddr, ptep, pte);
+	set_pte_at(args->mm, args->vaddr, args->ptep, pte);
 	barrier();
-	pte_clear(mm, vaddr, ptep);
-	pte = ptep_get(ptep);
+	pte_clear(args->mm, args->vaddr, args->ptep);
+	pte = ptep_get(args->ptep);
 	WARN_ON(!pte_none(pte));
 }
 
@@ -1224,7 +1224,7 @@ static int __init debug_vm_pgtable(void)
 	pgtable_t saved_ptep;
 	pgprot_t prot;
 	phys_addr_t paddr;
-	unsigned long vaddr, pte_aligned, pmd_aligned;
+	unsigned long vaddr, pmd_aligned;
 	unsigned long pud_aligned;
 	spinlock_t *ptl = NULL;
 	int idx, ret;
@@ -1259,10 +1259,8 @@ static int __init debug_vm_pgtable(void)
 	 */
 	paddr = __pa_symbol(&start_kernel);
 
-	pte_aligned = (paddr & PAGE_MASK) >> PAGE_SHIFT;
 	pmd_aligned = (paddr & PMD_MASK) >> PAGE_SHIFT;
 	pud_aligned = (paddr & PUD_MASK) >> PAGE_SHIFT;
-	WARN_ON(!pfn_valid(pte_aligned));
 
 	pgdp = pgd_offset(mm, vaddr);
 	p4dp = p4d_alloc(mm, pgdp, vaddr);
@@ -1344,9 +1342,9 @@ static int __init debug_vm_pgtable(void)
 	 * proper page table lock.
 	 */
 
-	ptep = pte_offset_map_lock(mm, pmdp, vaddr, &ptl);
-	pte_clear_tests(mm, ptep, pte_aligned, vaddr, prot);
-	pte_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
+	ptep = pte_offset_map_lock(args.mm, args.pmdp, args.vaddr, &ptl);
+	pte_clear_tests(&args);
+	pte_advanced_tests(&args);
 	pte_unmap_unlock(ptep, ptl);
 
 	ptl = pmd_lock(mm, pmdp);
-- 
2.23.0

[PATCH v5 08/12] mm/debug_vm_pgtable: Use struct pgtable_debug_args in PMD modifying tests

[Gavin Shan]

This uses struct pgtable_debug_args in PMD modifying tests. The allocated
huge page is used when set_pmd_at() is used. The corresponding tests
are skipped if the huge page doesn't exist. Besides, the unused variable
@pmd_aligned in debug_vm_pgtable() is dropped.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 mm/debug_vm_pgtable.c | 98 ++++++++++++++++++++-----------------------
 1 file changed, 46 insertions(+), 52 deletions(-)

diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index a9beac0b6ce0..a1f2a1e27ba2 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -211,54 +211,55 @@ static void __init pmd_basic_tests(struct pgtable_debug_args *args, int idx)
 	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, pgtable_t pgtable)
+static void __init pmd_advanced_tests(struct pgtable_debug_args *args)
 {
 	pmd_t pmd;
+	unsigned long vaddr = args->vaddr;
 
 	if (!has_transparent_hugepage())
 		return;
 
+	if (args->pmd_pfn == ULONG_MAX)
+		return;
+
 	pr_debug("Validating PMD advanced\n");
 	/* Align the address wrt HPAGE_PMD_SIZE */
 	vaddr &= HPAGE_PMD_MASK;
 
-	pgtable_trans_huge_deposit(mm, pmdp, pgtable);
+	pgtable_trans_huge_deposit(args->mm, args->pmdp, args->start_ptep);
 
-	pmd = pfn_pmd(pfn, prot);
-	set_pmd_at(mm, vaddr, pmdp, pmd);
-	pmdp_set_wrprotect(mm, vaddr, pmdp);
-	pmd = READ_ONCE(*pmdp);
+	pmd = pfn_pmd(args->pmd_pfn, args->page_prot);
+	set_pmd_at(args->mm, vaddr, args->pmdp, pmd);
+	pmdp_set_wrprotect(args->mm, vaddr, args->pmdp);
+	pmd = READ_ONCE(*args->pmdp);
 	WARN_ON(pmd_write(pmd));
-	pmdp_huge_get_and_clear(mm, vaddr, pmdp);
-	pmd = READ_ONCE(*pmdp);
+	pmdp_huge_get_and_clear(args->mm, vaddr, args->pmdp);
+	pmd = READ_ONCE(*args->pmdp);
 	WARN_ON(!pmd_none(pmd));
 
-	pmd = pfn_pmd(pfn, prot);
+	pmd = pfn_pmd(args->pmd_pfn, args->page_prot);
 	pmd = pmd_wrprotect(pmd);
 	pmd = pmd_mkclean(pmd);
-	set_pmd_at(mm, vaddr, pmdp, pmd);
+	set_pmd_at(args->mm, vaddr, args->pmdp, pmd);
 	pmd = pmd_mkwrite(pmd);
 	pmd = pmd_mkdirty(pmd);
-	pmdp_set_access_flags(vma, vaddr, pmdp, pmd, 1);
-	pmd = READ_ONCE(*pmdp);
+	pmdp_set_access_flags(args->vma, vaddr, args->pmdp, pmd, 1);
+	pmd = READ_ONCE(*args->pmdp);
 	WARN_ON(!(pmd_write(pmd) && pmd_dirty(pmd)));
-	pmdp_huge_get_and_clear_full(vma, vaddr, pmdp, 1);
-	pmd = READ_ONCE(*pmdp);
+	pmdp_huge_get_and_clear_full(args->vma, vaddr, args->pmdp, 1);
+	pmd = READ_ONCE(*args->pmdp);
 	WARN_ON(!pmd_none(pmd));
 
-	pmd = pmd_mkhuge(pfn_pmd(pfn, prot));
+	pmd = pmd_mkhuge(pfn_pmd(args->pmd_pfn, args->page_prot));
 	pmd = pmd_mkyoung(pmd);
-	set_pmd_at(mm, vaddr, pmdp, pmd);
-	pmdp_test_and_clear_young(vma, vaddr, pmdp);
-	pmd = READ_ONCE(*pmdp);
+	set_pmd_at(args->mm, vaddr, args->pmdp, pmd);
+	pmdp_test_and_clear_young(args->vma, vaddr, args->pmdp);
+	pmd = READ_ONCE(*args->pmdp);
 	WARN_ON(pmd_young(pmd));
 
 	/*  Clear the pte entries  */
-	pmdp_huge_get_and_clear(mm, vaddr, pmdp);
-	pgtable = pgtable_trans_huge_withdraw(mm, pmdp);
+	pmdp_huge_get_and_clear(args->mm, vaddr, args->pmdp);
+	pgtable_trans_huge_withdraw(args->mm, args->pmdp);
 }
 
 static void __init pmd_leaf_tests(struct pgtable_debug_args *args)
@@ -415,12 +416,7 @@ static void __init pud_leaf_tests(struct pgtable_debug_args *args) { }
 #else  /* !CONFIG_TRANSPARENT_HUGEPAGE */
 static void __init pmd_basic_tests(struct pgtable_debug_args *args, int idx) { }
 static void __init pud_basic_tests(struct pgtable_debug_args *args, int idx) { }
-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, pgtable_t pgtable)
-{
-}
+static void __init pmd_advanced_tests(struct pgtable_debug_args *args) { }
 static void __init pud_advanced_tests(struct mm_struct *mm,
 				      struct vm_area_struct *vma, pud_t *pudp,
 				      unsigned long pfn, unsigned long vaddr,
@@ -433,11 +429,11 @@ static void __init pmd_savedwrite_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
-static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot)
+static void __init pmd_huge_tests(struct pgtable_debug_args *args)
 {
 	pmd_t pmd;
 
-	if (!arch_vmap_pmd_supported(prot))
+	if (!arch_vmap_pmd_supported(args->page_prot))
 		return;
 
 	pr_debug("Validating PMD huge\n");
@@ -445,10 +441,10 @@ static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot)
 	 * 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);
+	WRITE_ONCE(*args->pmdp, __pmd(0));
+	WARN_ON(!pmd_set_huge(args->pmdp, __pfn_to_phys(args->fixed_pmd_pfn), args->page_prot));
+	WARN_ON(!pmd_clear_huge(args->pmdp));
+	pmd = READ_ONCE(*args->pmdp);
 	WARN_ON(!pmd_none(pmd));
 }
 
@@ -471,7 +467,7 @@ static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
 	WARN_ON(!pud_none(pud));
 }
 #else /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
-static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot) { }
+static void __init pmd_huge_tests(struct pgtable_debug_args *args) { }
 static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot) { }
 #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
 
@@ -635,20 +631,19 @@ static void __init pte_clear_tests(struct pgtable_debug_args *args)
 	WARN_ON(!pte_none(pte));
 }
 
-static void __init pmd_clear_tests(struct mm_struct *mm, pmd_t *pmdp)
+static void __init pmd_clear_tests(struct pgtable_debug_args *args)
 {
-	pmd_t pmd = READ_ONCE(*pmdp);
+	pmd_t pmd = READ_ONCE(*args->pmdp);
 
 	pr_debug("Validating PMD clear\n");
 	pmd = __pmd(pmd_val(pmd) | RANDOM_ORVALUE);
-	WRITE_ONCE(*pmdp, pmd);
-	pmd_clear(pmdp);
-	pmd = READ_ONCE(*pmdp);
+	WRITE_ONCE(*args->pmdp, pmd);
+	pmd_clear(args->pmdp);
+	pmd = READ_ONCE(*args->pmdp);
 	WARN_ON(!pmd_none(pmd));
 }
 
-static void __init pmd_populate_tests(struct mm_struct *mm, pmd_t *pmdp,
-				      pgtable_t pgtable)
+static void __init pmd_populate_tests(struct pgtable_debug_args *args)
 {
 	pmd_t pmd;
 
@@ -657,8 +652,8 @@ static void __init pmd_populate_tests(struct mm_struct *mm, pmd_t *pmdp,
 	 * This entry points to next level page table page.
 	 * Hence this must not qualify as pmd_bad().
 	 */
-	pmd_populate(mm, pmdp, pgtable);
-	pmd = READ_ONCE(*pmdp);
+	pmd_populate(args->mm, args->pmdp, args->start_ptep);
+	pmd = READ_ONCE(*args->pmdp);
 	WARN_ON(pmd_bad(pmd));
 }
 
@@ -1224,7 +1219,7 @@ static int __init debug_vm_pgtable(void)
 	pgtable_t saved_ptep;
 	pgprot_t prot;
 	phys_addr_t paddr;
-	unsigned long vaddr, pmd_aligned;
+	unsigned long vaddr;
 	unsigned long pud_aligned;
 	spinlock_t *ptl = NULL;
 	int idx, ret;
@@ -1259,7 +1254,6 @@ static int __init debug_vm_pgtable(void)
 	 */
 	paddr = __pa_symbol(&start_kernel);
 
-	pmd_aligned = (paddr & PMD_MASK) >> PAGE_SHIFT;
 	pud_aligned = (paddr & PUD_MASK) >> PAGE_SHIFT;
 
 	pgdp = pgd_offset(mm, vaddr);
@@ -1347,11 +1341,11 @@ static int __init debug_vm_pgtable(void)
 	pte_advanced_tests(&args);
 	pte_unmap_unlock(ptep, ptl);
 
-	ptl = pmd_lock(mm, pmdp);
-	pmd_clear_tests(mm, pmdp);
-	pmd_advanced_tests(mm, vma, pmdp, pmd_aligned, vaddr, prot, saved_ptep);
-	pmd_huge_tests(pmdp, pmd_aligned, prot);
-	pmd_populate_tests(mm, pmdp, saved_ptep);
+	ptl = pmd_lock(args.mm, args.pmdp);
+	pmd_clear_tests(&args);
+	pmd_advanced_tests(&args);
+	pmd_huge_tests(&args);
+	pmd_populate_tests(&args);
 	spin_unlock(ptl);
 
 	ptl = pud_lock(mm, pudp);
-- 
2.23.0

[PATCH v5 09/12] mm/debug_vm_pgtable: Use struct pgtable_debug_args in PUD modifying tests

[Gavin Shan]

This uses struct pgtable_debug_args in PUD modifying tests. The allocated
huge page is used when set_pud_at() is used. The corresponding tests
are skipped if the huge page doesn't exist. Besides, the following unused
variables in debug_vm_pgtable() are dropped: @prot, @paddr, @pud_aligned.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 mm/debug_vm_pgtable.c | 126 ++++++++++++++++--------------------------
 1 file changed, 48 insertions(+), 78 deletions(-)

diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index a1f2a1e27ba2..460bf0101a49 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -337,55 +337,56 @@ static void __init pud_basic_tests(struct pgtable_debug_args *args, int idx)
 	WARN_ON(!pud_bad(pud_mkhuge(pud)));
 }
 
-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 pud_advanced_tests(struct pgtable_debug_args *args)
 {
+	unsigned long vaddr = args->vaddr;
 	pud_t pud;
 
 	if (!has_transparent_hugepage())
 		return;
 
+	if (args->pud_pfn == ULONG_MAX)
+		return;
+
 	pr_debug("Validating PUD advanced\n");
 	/* Align the address wrt HPAGE_PUD_SIZE */
 	vaddr &= HPAGE_PUD_MASK;
 
-	pud = pfn_pud(pfn, prot);
-	set_pud_at(mm, vaddr, pudp, pud);
-	pudp_set_wrprotect(mm, vaddr, pudp);
-	pud = READ_ONCE(*pudp);
+	pud = pfn_pud(args->pud_pfn, args->page_prot);
+	set_pud_at(args->mm, vaddr, args->pudp, pud);
+	pudp_set_wrprotect(args->mm, vaddr, args->pudp);
+	pud = READ_ONCE(*args->pudp);
 	WARN_ON(pud_write(pud));
 
 #ifndef __PAGETABLE_PMD_FOLDED
-	pudp_huge_get_and_clear(mm, vaddr, pudp);
-	pud = READ_ONCE(*pudp);
+	pudp_huge_get_and_clear(args->mm, vaddr, args->pudp);
+	pud = READ_ONCE(*args->pudp);
 	WARN_ON(!pud_none(pud));
 #endif /* __PAGETABLE_PMD_FOLDED */
-	pud = pfn_pud(pfn, prot);
+	pud = pfn_pud(args->pud_pfn, args->page_prot);
 	pud = pud_wrprotect(pud);
 	pud = pud_mkclean(pud);
-	set_pud_at(mm, vaddr, pudp, pud);
+	set_pud_at(args->mm, vaddr, args->pudp, pud);
 	pud = pud_mkwrite(pud);
 	pud = pud_mkdirty(pud);
-	pudp_set_access_flags(vma, vaddr, pudp, pud, 1);
-	pud = READ_ONCE(*pudp);
+	pudp_set_access_flags(args->vma, vaddr, args->pudp, pud, 1);
+	pud = READ_ONCE(*args->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);
+	pudp_huge_get_and_clear_full(args->mm, vaddr, args->pudp, 1);
+	pud = READ_ONCE(*args->pudp);
 	WARN_ON(!pud_none(pud));
 #endif /* __PAGETABLE_PMD_FOLDED */
 
-	pud = pfn_pud(pfn, prot);
+	pud = pfn_pud(args->pud_pfn, args->page_prot);
 	pud = pud_mkyoung(pud);
-	set_pud_at(mm, vaddr, pudp, pud);
-	pudp_test_and_clear_young(vma, vaddr, pudp);
-	pud = READ_ONCE(*pudp);
+	set_pud_at(args->mm, vaddr, args->pudp, pud);
+	pudp_test_and_clear_young(args->vma, vaddr, args->pudp);
+	pud = READ_ONCE(*args->pudp);
 	WARN_ON(pud_young(pud));
 
-	pudp_huge_get_and_clear(mm, vaddr, pudp);
+	pudp_huge_get_and_clear(args->mm, vaddr, args->pudp);
 }
 
 static void __init pud_leaf_tests(struct pgtable_debug_args *args)
@@ -405,24 +406,14 @@ static void __init pud_leaf_tests(struct pgtable_debug_args *args)
 }
 #else  /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 static void __init pud_basic_tests(struct pgtable_debug_args *args, int idx) { }
-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 pud_advanced_tests(struct pgtable_debug_args *args) { }
 static void __init pud_leaf_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 #else  /* !CONFIG_TRANSPARENT_HUGEPAGE */
 static void __init pmd_basic_tests(struct pgtable_debug_args *args, int idx) { }
 static void __init pud_basic_tests(struct pgtable_debug_args *args, int idx) { }
 static void __init pmd_advanced_tests(struct pgtable_debug_args *args) { }
-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 pud_advanced_tests(struct pgtable_debug_args *args) { }
 static void __init pmd_leaf_tests(struct pgtable_debug_args *args) { }
 static void __init pud_leaf_tests(struct pgtable_debug_args *args) { }
 static void __init pmd_savedwrite_tests(struct pgtable_debug_args *args) { }
@@ -448,11 +439,11 @@ static void __init pmd_huge_tests(struct pgtable_debug_args *args)
 	WARN_ON(!pmd_none(pmd));
 }
 
-static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
+static void __init pud_huge_tests(struct pgtable_debug_args *args)
 {
 	pud_t pud;
 
-	if (!arch_vmap_pud_supported(prot))
+	if (!arch_vmap_pud_supported(args->page_prot))
 		return;
 
 	pr_debug("Validating PUD huge\n");
@@ -460,15 +451,15 @@ static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
 	 * 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);
+	WRITE_ONCE(*args->pudp, __pud(0));
+	WARN_ON(!pud_set_huge(args->pudp, __pfn_to_phys(args->fixed_pud_pfn), args->page_prot));
+	WARN_ON(!pud_clear_huge(args->pudp));
+	pud = READ_ONCE(*args->pudp);
 	WARN_ON(!pud_none(pud));
 }
 #else /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
 static void __init pmd_huge_tests(struct pgtable_debug_args *args) { }
-static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot) { }
+static void __init pud_huge_tests(struct pgtable_debug_args *args) { }
 #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
 
 static void __init p4d_basic_tests(struct pgtable_debug_args *args)
@@ -490,27 +481,26 @@ static void __init pgd_basic_tests(struct pgtable_debug_args *args)
 }
 
 #ifndef __PAGETABLE_PUD_FOLDED
-static void __init pud_clear_tests(struct mm_struct *mm, pud_t *pudp)
+static void __init pud_clear_tests(struct pgtable_debug_args *args)
 {
-	pud_t pud = READ_ONCE(*pudp);
+	pud_t pud = READ_ONCE(*args->pudp);
 
-	if (mm_pmd_folded(mm))
+	if (mm_pmd_folded(args->mm))
 		return;
 
 	pr_debug("Validating PUD clear\n");
 	pud = __pud(pud_val(pud) | RANDOM_ORVALUE);
-	WRITE_ONCE(*pudp, pud);
-	pud_clear(pudp);
-	pud = READ_ONCE(*pudp);
+	WRITE_ONCE(*args->pudp, pud);
+	pud_clear(args->pudp);
+	pud = READ_ONCE(*args->pudp);
 	WARN_ON(!pud_none(pud));
 }
 
-static void __init pud_populate_tests(struct mm_struct *mm, pud_t *pudp,
-				      pmd_t *pmdp)
+static void __init pud_populate_tests(struct pgtable_debug_args *args)
 {
 	pud_t pud;
 
-	if (mm_pmd_folded(mm))
+	if (mm_pmd_folded(args->mm))
 		return;
 
 	pr_debug("Validating PUD populate\n");
@@ -518,16 +508,13 @@ static void __init pud_populate_tests(struct mm_struct *mm, pud_t *pudp,
 	 * This entry points to next level page table page.
 	 * Hence this must not qualify as pud_bad().
 	 */
-	pud_populate(mm, pudp, pmdp);
-	pud = READ_ONCE(*pudp);
+	pud_populate(args->mm, args->pudp, args->start_pmdp);
+	pud = READ_ONCE(*args->pudp);
 	WARN_ON(pud_bad(pud));
 }
 #else  /* !__PAGETABLE_PUD_FOLDED */
-static void __init pud_clear_tests(struct mm_struct *mm, pud_t *pudp) { }
-static void __init pud_populate_tests(struct mm_struct *mm, pud_t *pudp,
-				      pmd_t *pmdp)
-{
-}
+static void __init pud_clear_tests(struct pgtable_debug_args *args) { }
+static void __init pud_populate_tests(struct pgtable_debug_args *args) { }
 #endif /* PAGETABLE_PUD_FOLDED */
 
 #ifndef __PAGETABLE_P4D_FOLDED
@@ -1217,10 +1204,7 @@ static int __init debug_vm_pgtable(void)
 	pmd_t *pmdp, *saved_pmdp, pmd;
 	pte_t *ptep;
 	pgtable_t saved_ptep;
-	pgprot_t prot;
-	phys_addr_t paddr;
 	unsigned long vaddr;
-	unsigned long pud_aligned;
 	spinlock_t *ptl = NULL;
 	int idx, ret;
 
@@ -1229,7 +1213,6 @@ static int __init debug_vm_pgtable(void)
 	if (ret)
 		return ret;
 
-	prot = vm_get_page_prot(VMFLAGS);
 	vaddr = get_random_vaddr();
 	mm = mm_alloc();
 	if (!mm) {
@@ -1243,19 +1226,6 @@ static int __init debug_vm_pgtable(void)
 		return 1;
 	}
 
-	/*
-	 * PFN for mapping at PTE level is determined from a standard kernel
-	 * text symbol. But pfns for higher page table levels are derived by
-	 * masking lower bits of this real pfn. These derived pfns might not
-	 * exist on the platform but that does not really matter as pfn_pxx()
-	 * helpers will still create appropriate entries for the test. This
-	 * helps avoid large memory block allocations to be used for mapping
-	 * at higher page table levels.
-	 */
-	paddr = __pa_symbol(&start_kernel);
-
-	pud_aligned = (paddr & PUD_MASK) >> PAGE_SHIFT;
-
 	pgdp = pgd_offset(mm, vaddr);
 	p4dp = p4d_alloc(mm, pgdp, vaddr);
 	pudp = pud_alloc(mm, p4dp, vaddr);
@@ -1348,11 +1318,11 @@ static int __init debug_vm_pgtable(void)
 	pmd_populate_tests(&args);
 	spin_unlock(ptl);
 
-	ptl = pud_lock(mm, pudp);
-	pud_clear_tests(mm, pudp);
-	pud_advanced_tests(mm, vma, pudp, pud_aligned, vaddr, prot);
-	pud_huge_tests(pudp, pud_aligned, prot);
-	pud_populate_tests(mm, pudp, saved_pmdp);
+	ptl = pud_lock(args.mm, args.pudp);
+	pud_clear_tests(&args);
+	pud_advanced_tests(&args);
+	pud_huge_tests(&args);
+	pud_populate_tests(&args);
 	spin_unlock(ptl);
 
 	spin_lock(&mm->page_table_lock);
-- 
2.23.0

[PATCH v5 10/12] mm/debug_vm_pgtable: Use struct pgtable_debug_args in PGD and P4D modifying tests

[Gavin Shan]

This uses struct pgtable_debug_args in PGD/P4D modifying tests. No
allocated huge page is used in these tests. Besides, the unused
variable @saved_p4dp and @saved_pudp are dropped.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 mm/debug_vm_pgtable.c | 86 +++++++++++++++++++------------------------
 1 file changed, 38 insertions(+), 48 deletions(-)

diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index 460bf0101a49..3828d2bdf5de 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -518,27 +518,26 @@ static void __init pud_populate_tests(struct pgtable_debug_args *args) { }
 #endif /* PAGETABLE_PUD_FOLDED */
 
 #ifndef __PAGETABLE_P4D_FOLDED
-static void __init p4d_clear_tests(struct mm_struct *mm, p4d_t *p4dp)
+static void __init p4d_clear_tests(struct pgtable_debug_args *args)
 {
-	p4d_t p4d = READ_ONCE(*p4dp);
+	p4d_t p4d = READ_ONCE(*args->p4dp);
 
-	if (mm_pud_folded(mm))
+	if (mm_pud_folded(args->mm))
 		return;
 
 	pr_debug("Validating P4D clear\n");
 	p4d = __p4d(p4d_val(p4d) | RANDOM_ORVALUE);
-	WRITE_ONCE(*p4dp, p4d);
-	p4d_clear(p4dp);
-	p4d = READ_ONCE(*p4dp);
+	WRITE_ONCE(*args->p4dp, p4d);
+	p4d_clear(args->p4dp);
+	p4d = READ_ONCE(*args->p4dp);
 	WARN_ON(!p4d_none(p4d));
 }
 
-static void __init p4d_populate_tests(struct mm_struct *mm, p4d_t *p4dp,
-				      pud_t *pudp)
+static void __init p4d_populate_tests(struct pgtable_debug_args *args)
 {
 	p4d_t p4d;
 
-	if (mm_pud_folded(mm))
+	if (mm_pud_folded(args->mm))
 		return;
 
 	pr_debug("Validating P4D populate\n");
@@ -546,34 +545,33 @@ static void __init p4d_populate_tests(struct mm_struct *mm, p4d_t *p4dp,
 	 * This entry points to next level page table page.
 	 * Hence this must not qualify as p4d_bad().
 	 */
-	pud_clear(pudp);
-	p4d_clear(p4dp);
-	p4d_populate(mm, p4dp, pudp);
-	p4d = READ_ONCE(*p4dp);
+	pud_clear(args->pudp);
+	p4d_clear(args->p4dp);
+	p4d_populate(args->mm, args->p4dp, args->start_pudp);
+	p4d = READ_ONCE(*args->p4dp);
 	WARN_ON(p4d_bad(p4d));
 }
 
-static void __init pgd_clear_tests(struct mm_struct *mm, pgd_t *pgdp)
+static void __init pgd_clear_tests(struct pgtable_debug_args *args)
 {
-	pgd_t pgd = READ_ONCE(*pgdp);
+	pgd_t pgd = READ_ONCE(*(args->pgdp));
 
-	if (mm_p4d_folded(mm))
+	if (mm_p4d_folded(args->mm))
 		return;
 
 	pr_debug("Validating PGD clear\n");
 	pgd = __pgd(pgd_val(pgd) | RANDOM_ORVALUE);
-	WRITE_ONCE(*pgdp, pgd);
-	pgd_clear(pgdp);
-	pgd = READ_ONCE(*pgdp);
+	WRITE_ONCE(*args->pgdp, pgd);
+	pgd_clear(args->pgdp);
+	pgd = READ_ONCE(*args->pgdp);
 	WARN_ON(!pgd_none(pgd));
 }
 
-static void __init pgd_populate_tests(struct mm_struct *mm, pgd_t *pgdp,
-				      p4d_t *p4dp)
+static void __init pgd_populate_tests(struct pgtable_debug_args *args)
 {
 	pgd_t pgd;
 
-	if (mm_p4d_folded(mm))
+	if (mm_p4d_folded(args->mm))
 		return;
 
 	pr_debug("Validating PGD populate\n");
@@ -581,23 +579,17 @@ static void __init pgd_populate_tests(struct mm_struct *mm, pgd_t *pgdp,
 	 * This entry points to next level page table page.
 	 * Hence this must not qualify as pgd_bad().
 	 */
-	p4d_clear(p4dp);
-	pgd_clear(pgdp);
-	pgd_populate(mm, pgdp, p4dp);
-	pgd = READ_ONCE(*pgdp);
+	p4d_clear(args->p4dp);
+	pgd_clear(args->pgdp);
+	pgd_populate(args->mm, args->pgdp, args->start_p4dp);
+	pgd = READ_ONCE(*args->pgdp);
 	WARN_ON(pgd_bad(pgd));
 }
 #else  /* !__PAGETABLE_P4D_FOLDED */
-static void __init p4d_clear_tests(struct mm_struct *mm, p4d_t *p4dp) { }
-static void __init pgd_clear_tests(struct mm_struct *mm, pgd_t *pgdp) { }
-static void __init p4d_populate_tests(struct mm_struct *mm, p4d_t *p4dp,
-				      pud_t *pudp)
-{
-}
-static void __init pgd_populate_tests(struct mm_struct *mm, pgd_t *pgdp,
-				      p4d_t *p4dp)
-{
-}
+static void __init p4d_clear_tests(struct pgtable_debug_args *args) { }
+static void __init pgd_clear_tests(struct pgtable_debug_args *args) { }
+static void __init p4d_populate_tests(struct pgtable_debug_args *args) { }
+static void __init pgd_populate_tests(struct pgtable_debug_args *args) { }
 #endif /* PAGETABLE_P4D_FOLDED */
 
 static void __init pte_clear_tests(struct pgtable_debug_args *args)
@@ -1199,8 +1191,8 @@ static int __init debug_vm_pgtable(void)
 	struct vm_area_struct *vma;
 	struct mm_struct *mm;
 	pgd_t *pgdp;
-	p4d_t *p4dp, *saved_p4dp;
-	pud_t *pudp, *saved_pudp;
+	p4d_t *p4dp;
+	pud_t *pudp;
 	pmd_t *pmdp, *saved_pmdp, pmd;
 	pte_t *ptep;
 	pgtable_t saved_ptep;
@@ -1245,8 +1237,6 @@ static int __init debug_vm_pgtable(void)
 	 * page table pages.
 	 */
 	pmd = READ_ONCE(*pmdp);
-	saved_p4dp = p4d_offset(pgdp, 0UL);
-	saved_pudp = pud_offset(p4dp, 0UL);
 	saved_pmdp = pmd_offset(pudp, 0UL);
 	saved_ptep = pmd_pgtable(pmd);
 
@@ -1325,15 +1315,15 @@ static int __init debug_vm_pgtable(void)
 	pud_populate_tests(&args);
 	spin_unlock(ptl);
 
-	spin_lock(&mm->page_table_lock);
-	p4d_clear_tests(mm, p4dp);
-	pgd_clear_tests(mm, pgdp);
-	p4d_populate_tests(mm, p4dp, saved_pudp);
-	pgd_populate_tests(mm, pgdp, saved_p4dp);
-	spin_unlock(&mm->page_table_lock);
+	spin_lock(&(args.mm->page_table_lock));
+	p4d_clear_tests(&args);
+	pgd_clear_tests(&args);
+	p4d_populate_tests(&args);
+	pgd_populate_tests(&args);
+	spin_unlock(&(args.mm->page_table_lock));
 
-	p4d_free(mm, saved_p4dp);
-	pud_free(mm, saved_pudp);
+	p4d_free(mm, p4d_offset(pgdp, 0UL));
+	pud_free(mm, pud_offset(p4dp, 0UL));
 	pmd_free(mm, saved_pmdp);
 	pte_free(mm, saved_ptep);
 
-- 
2.23.0

[PATCH v5 11/12] mm/debug_vm_pgtable: Remove unused code

[Gavin Shan]

The variables used by old implementation isn't needed as we switched
to "struct pgtable_debug_args". Lets remove them and related code in
debug_vm_pgtable().

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 mm/debug_vm_pgtable.c | 54 -------------------------------------------
 1 file changed, 54 deletions(-)

diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index 3828d2bdf5de..b4fdc63a60f0 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -1188,15 +1188,7 @@ static int __init init_args(struct pgtable_debug_args *args)
 static int __init debug_vm_pgtable(void)
 {
 	struct pgtable_debug_args args;
-	struct vm_area_struct *vma;
-	struct mm_struct *mm;
-	pgd_t *pgdp;
-	p4d_t *p4dp;
-	pud_t *pudp;
-	pmd_t *pmdp, *saved_pmdp, pmd;
 	pte_t *ptep;
-	pgtable_t saved_ptep;
-	unsigned long vaddr;
 	spinlock_t *ptl = NULL;
 	int idx, ret;
 
@@ -1205,41 +1197,6 @@ static int __init debug_vm_pgtable(void)
 	if (ret)
 		return ret;
 
-	vaddr = get_random_vaddr();
-	mm = mm_alloc();
-	if (!mm) {
-		pr_err("mm_struct allocation failed\n");
-		return 1;
-	}
-
-	vma = vm_area_alloc(mm);
-	if (!vma) {
-		pr_err("vma allocation failed\n");
-		return 1;
-	}
-
-	pgdp = pgd_offset(mm, vaddr);
-	p4dp = p4d_alloc(mm, pgdp, vaddr);
-	pudp = pud_alloc(mm, p4dp, vaddr);
-	pmdp = pmd_alloc(mm, pudp, vaddr);
-	/*
-	 * Allocate pgtable_t
-	 */
-	if (pte_alloc(mm, pmdp)) {
-		pr_err("pgtable allocation failed\n");
-		return 1;
-	}
-
-	/*
-	 * Save all the page table page addresses as the page table
-	 * entries will be used for testing with random or garbage
-	 * values. These saved addresses will be used for freeing
-	 * page table pages.
-	 */
-	pmd = READ_ONCE(*pmdp);
-	saved_pmdp = pmd_offset(pudp, 0UL);
-	saved_ptep = pmd_pgtable(pmd);
-
 	/*
 	 * Iterate over the protection_map[] to make sure that all
 	 * the basic page table transformation validations just hold
@@ -1322,17 +1279,6 @@ static int __init debug_vm_pgtable(void)
 	pgd_populate_tests(&args);
 	spin_unlock(&(args.mm->page_table_lock));
 
-	p4d_free(mm, p4d_offset(pgdp, 0UL));
-	pud_free(mm, pud_offset(p4dp, 0UL));
-	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);
-	mmdrop(mm);
-
 	destroy_args(&args);
 	return 0;
 }
-- 
2.23.0

[PATCH v5 12/12] mm/debug_vm_pgtable: Fix corrupted page flag

[Gavin Shan]

In page table entry modifying tests, set_xxx_at() are used to populate
the page table entries. On ARM64, PG_arch_1 (PG_dcache_clean) flag is
set to the target page flag if execution permission is given. The logic
exits since commit 4f04d8f00545 ("arm64: MMU definitions"). The page
flag is kept when the page is free'd to buddy's free area list. However,
it will trigger page checking failure when it's pulled from the buddy's
free area list, as the following warning messages indicate.

   BUG: Bad page state in process memhog  pfn:08000
   page:0000000015c0a628 refcount:0 mapcount:0 \
        mapping:0000000000000000 index:0x1 pfn:0x8000
   flags: 0x7ffff8000000800(arch_1|node=0|zone=0|lastcpupid=0xfffff)
   raw: 07ffff8000000800 dead000000000100 dead000000000122 0000000000000000
   raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
   page dumped because: PAGE_FLAGS_CHECK_AT_PREP flag(s) set

This fixes the issue by clearing PG_arch_1 through flush_dcache_page()
after set_xxx_at() is called. For architectures other than ARM64, the
unexpected overhead of cache flushing is acceptable.

Fixes: a5c3b9ffb0f4 ("mm/debug_vm_pgtable: add tests validating advanced arch page table helpers")
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 mm/debug_vm_pgtable.c | 55 +++++++++++++++++++++++++++++++++++++++----
 1 file changed, 51 insertions(+), 4 deletions(-)

diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index b4fdc63a60f0..f0202a92226f 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -29,6 +29,8 @@
 #include <linux/start_kernel.h>
 #include <linux/sched/mm.h>
 #include <linux/io.h>
+
+#include <asm/cacheflush.h>
 #include <asm/pgalloc.h>
 #include <asm/tlbflush.h>
 
@@ -119,19 +121,28 @@ static void __init pte_basic_tests(struct pgtable_debug_args *args, int idx)
 
 static void __init pte_advanced_tests(struct pgtable_debug_args *args)
 {
+	struct page *page;
 	pte_t pte;
 
 	/*
 	 * 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
+	 *
+	 * flush_dcache_page() is called after set_pte_at() to clear
+	 * PG_arch_1 for the page on ARM64. The page flag isn't cleared
+	 * when it's released and page allocation check will fail when
+	 * the page is allocated again. For architectures other than ARM64,
+	 * the unexpected overhead of cache flushing is acceptable.
 	 */
-	if (args->pte_pfn == ULONG_MAX)
+	page = (args->pte_pfn != ULONG_MAX) ? pfn_to_page(args->pte_pfn) : NULL;
+	if (!page)
 		return;
 
 	pr_debug("Validating PTE advanced\n");
 	pte = pfn_pte(args->pte_pfn, args->page_prot);
 	set_pte_at(args->mm, args->vaddr, args->ptep, pte);
+	flush_dcache_page(page);
 	ptep_set_wrprotect(args->mm, args->vaddr, args->ptep);
 	pte = ptep_get(args->ptep);
 	WARN_ON(pte_write(pte));
@@ -143,6 +154,7 @@ static void __init pte_advanced_tests(struct pgtable_debug_args *args)
 	pte = pte_wrprotect(pte);
 	pte = pte_mkclean(pte);
 	set_pte_at(args->mm, args->vaddr, args->ptep, pte);
+	flush_dcache_page(page);
 	pte = pte_mkwrite(pte);
 	pte = pte_mkdirty(pte);
 	ptep_set_access_flags(args->vma, args->vaddr, args->ptep, pte, 1);
@@ -155,6 +167,7 @@ static void __init pte_advanced_tests(struct pgtable_debug_args *args)
 	pte = pfn_pte(args->pte_pfn, args->page_prot);
 	pte = pte_mkyoung(pte);
 	set_pte_at(args->mm, args->vaddr, args->ptep, pte);
+	flush_dcache_page(page);
 	ptep_test_and_clear_young(args->vma, args->vaddr, args->ptep);
 	pte = ptep_get(args->ptep);
 	WARN_ON(pte_young(pte));
@@ -213,15 +226,24 @@ static void __init pmd_basic_tests(struct pgtable_debug_args *args, int idx)
 
 static void __init pmd_advanced_tests(struct pgtable_debug_args *args)
 {
+	struct page *page;
 	pmd_t pmd;
 	unsigned long vaddr = args->vaddr;
 
 	if (!has_transparent_hugepage())
 		return;
 
-	if (args->pmd_pfn == ULONG_MAX)
+	page = (args->pmd_pfn != ULONG_MAX) ? pfn_to_page(args->pmd_pfn) : NULL;
+	if (!page)
 		return;
 
+	/*
+	 * flush_dcache_page() is called after set_pmd_at() to clear
+	 * PG_arch_1 for the page on ARM64. The page flag isn't cleared
+	 * when it's released and page allocation check will fail when
+	 * the page is allocated again. For architectures other than ARM64,
+	 * the unexpected overhead of cache flushing is acceptable.
+	 */
 	pr_debug("Validating PMD advanced\n");
 	/* Align the address wrt HPAGE_PMD_SIZE */
 	vaddr &= HPAGE_PMD_MASK;
@@ -230,6 +252,7 @@ static void __init pmd_advanced_tests(struct pgtable_debug_args *args)
 
 	pmd = pfn_pmd(args->pmd_pfn, args->page_prot);
 	set_pmd_at(args->mm, vaddr, args->pmdp, pmd);
+	flush_dcache_page(page);
 	pmdp_set_wrprotect(args->mm, vaddr, args->pmdp);
 	pmd = READ_ONCE(*args->pmdp);
 	WARN_ON(pmd_write(pmd));
@@ -241,6 +264,7 @@ static void __init pmd_advanced_tests(struct pgtable_debug_args *args)
 	pmd = pmd_wrprotect(pmd);
 	pmd = pmd_mkclean(pmd);
 	set_pmd_at(args->mm, vaddr, args->pmdp, pmd);
+	flush_dcache_page(page);
 	pmd = pmd_mkwrite(pmd);
 	pmd = pmd_mkdirty(pmd);
 	pmdp_set_access_flags(args->vma, vaddr, args->pmdp, pmd, 1);
@@ -253,6 +277,7 @@ static void __init pmd_advanced_tests(struct pgtable_debug_args *args)
 	pmd = pmd_mkhuge(pfn_pmd(args->pmd_pfn, args->page_prot));
 	pmd = pmd_mkyoung(pmd);
 	set_pmd_at(args->mm, vaddr, args->pmdp, pmd);
+	flush_dcache_page(page);
 	pmdp_test_and_clear_young(args->vma, vaddr, args->pmdp);
 	pmd = READ_ONCE(*args->pmdp);
 	WARN_ON(pmd_young(pmd));
@@ -339,21 +364,31 @@ static void __init pud_basic_tests(struct pgtable_debug_args *args, int idx)
 
 static void __init pud_advanced_tests(struct pgtable_debug_args *args)
 {
+	struct page *page;
 	unsigned long vaddr = args->vaddr;
 	pud_t pud;
 
 	if (!has_transparent_hugepage())
 		return;
 
-	if (args->pud_pfn == ULONG_MAX)
+	page = (args->pud_pfn != ULONG_MAX) ? pfn_to_page(args->pud_pfn) : NULL;
+	if (!page)
 		return;
 
+	/*
+	 * flush_dcache_page() is called after set_pud_at() to clear
+	 * PG_arch_1 for the page on ARM64. The page flag isn't cleared
+	 * when it's released and page allocation check will fail when
+	 * the page is allocated again. For architectures other than ARM64,
+	 * the unexpected overhead of cache flushing is acceptable.
+	 */
 	pr_debug("Validating PUD advanced\n");
 	/* Align the address wrt HPAGE_PUD_SIZE */
 	vaddr &= HPAGE_PUD_MASK;
 
 	pud = pfn_pud(args->pud_pfn, args->page_prot);
 	set_pud_at(args->mm, vaddr, args->pudp, pud);
+	flush_dcache_page(page);
 	pudp_set_wrprotect(args->mm, vaddr, args->pudp);
 	pud = READ_ONCE(*args->pudp);
 	WARN_ON(pud_write(pud));
@@ -367,6 +402,7 @@ static void __init pud_advanced_tests(struct pgtable_debug_args *args)
 	pud = pud_wrprotect(pud);
 	pud = pud_mkclean(pud);
 	set_pud_at(args->mm, vaddr, args->pudp, pud);
+	flush_dcache_page(page);
 	pud = pud_mkwrite(pud);
 	pud = pud_mkdirty(pud);
 	pudp_set_access_flags(args->vma, vaddr, args->pudp, pud, 1);
@@ -382,6 +418,7 @@ static void __init pud_advanced_tests(struct pgtable_debug_args *args)
 	pud = pfn_pud(args->pud_pfn, args->page_prot);
 	pud = pud_mkyoung(pud);
 	set_pud_at(args->mm, vaddr, args->pudp, pud);
+	flush_dcache_page(page);
 	pudp_test_and_clear_young(args->vma, vaddr, args->pudp);
 	pud = READ_ONCE(*args->pudp);
 	WARN_ON(pud_young(pud));
@@ -594,16 +631,26 @@ static void __init pgd_populate_tests(struct pgtable_debug_args *args) { }
 
 static void __init pte_clear_tests(struct pgtable_debug_args *args)
 {
+	struct page *page;
 	pte_t pte = pfn_pte(args->pte_pfn, args->page_prot);
 
-	if (args->pte_pfn == ULONG_MAX)
+	page = (args->pte_pfn != ULONG_MAX) ? pfn_to_page(args->pte_pfn) : NULL;
+	if (!page)
 		return;
 
+	/*
+	 * flush_dcache_page() is called after set_pte_at() to clear
+	 * PG_arch_1 for the page on ARM64. The page flag isn't cleared
+	 * when it's released and page allocation check will fail when
+	 * the page is allocated again. For architectures other than ARM64,
+	 * the unexpected overhead of cache flushing is acceptable.
+	 */
 	pr_debug("Validating PTE clear\n");
 #ifndef CONFIG_RISCV
 	pte = __pte(pte_val(pte) | RANDOM_ORVALUE);
 #endif
 	set_pte_at(args->mm, args->vaddr, args->ptep, pte);
+	flush_dcache_page(page);
 	barrier();
 	pte_clear(args->mm, args->vaddr, args->ptep);
 	pte = ptep_get(args->ptep);
-- 
2.23.0

Re: [PATCH v5 01/12] mm/debug_vm_pgtable: Introduce struct pgtable_debug_args

[Anshuman Khandual]

On 8/2/21 11:34 AM, Gavin Shan wrote:
> In debug_vm_pgtable(), there are many local variables introduced to
> track the needed information and they are passed to the functions for
> various test cases. It'd better to introduce a struct as place holder
> for these information. With it, what the tests functions need is the
> struct. In this way, the code is simplified and easier to be maintained.
> 
> Besides, set_xxx_at() could access the data on the corresponding pages
> in the page table modifying tests. So the accessed pages in the tests
> should have been allocated from buddy. Otherwise, we're accessing pages
> that aren't owned by us. This causes issues like page flag corruption
> or kernel crash on accessing unmapped page when CONFIG_DEBUG_PAGEALLOC
> is enabled.
> 
> This introduces "struct pgtable_debug_args". The struct is initialized
> and destroyed, but the information in the struct isn't used yet. It will
> be used in subsequent patches.
> 
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
>  mm/debug_vm_pgtable.c | 269 +++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 268 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
> index 1c922691aa61..6a825f0e7cd7 100644
> --- a/mm/debug_vm_pgtable.c
> +++ b/mm/debug_vm_pgtable.c
> @@ -58,6 +58,37 @@
>  #define RANDOM_ORVALUE (GENMASK(BITS_PER_LONG - 1, 0) & ~ARCH_SKIP_MASK)
>  #define RANDOM_NZVALUE	GENMASK(7, 0)
>  
> +struct pgtable_debug_args {
> +	struct mm_struct	*mm;
> +	struct vm_area_struct	*vma;
> +
> +	pgd_t			*pgdp;
> +	p4d_t			*p4dp;
> +	pud_t			*pudp;
> +	pmd_t			*pmdp;
> +	pte_t			*ptep;
> +
> +	p4d_t			*start_p4dp;
> +	pud_t			*start_pudp;
> +	pmd_t			*start_pmdp;
> +	pgtable_t		start_ptep;
> +
> +	unsigned long		vaddr;
> +	pgprot_t		page_prot;
> +	pgprot_t		page_prot_none;
> +
> +	bool			is_contiguous_page;
> +	unsigned long		pud_pfn;
> +	unsigned long		pmd_pfn;
> +	unsigned long		pte_pfn;
> +
> +	unsigned long		fixed_pgd_pfn;
> +	unsigned long		fixed_p4d_pfn;
> +	unsigned long		fixed_pud_pfn;
> +	unsigned long		fixed_pmd_pfn;
> +	unsigned long		fixed_pte_pfn;
> +};
> +
>  static void __init pte_basic_tests(unsigned long pfn, int idx)
>  {
>  	pgprot_t prot = protection_map[idx];
> @@ -955,8 +986,238 @@ static unsigned long __init get_random_vaddr(void)
>  	return random_vaddr;
>  }
>  
> +static void __init destroy_args(struct pgtable_debug_args *args)
> +{
> +	struct page *page = NULL;
> +
> +	/* Free (huge) page */
> +	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
> +	    IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) &&
> +	    has_transparent_hugepage() &&
> +	    args->pud_pfn != ULONG_MAX) {
> +		if (args->is_contiguous_page) {
> +			free_contig_range(args->pud_pfn,
> +					  (1 << (HPAGE_PUD_SHIFT - PAGE_SHIFT)));
> +		} else {
> +			page = pfn_to_page(args->pud_pfn);
> +			__free_pages(page, HPAGE_PUD_SHIFT - PAGE_SHIFT);
> +		}
> +
> +		args->pud_pfn = ULONG_MAX;
> +		args->pmd_pfn = ULONG_MAX;
> +		args->pte_pfn = ULONG_MAX;
> +	}
> +
> +	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
> +	    has_transparent_hugepage() &&
> +	    args->pmd_pfn != ULONG_MAX) {
> +		if (args->is_contiguous_page) {
> +			free_contig_range(args->pmd_pfn, (1 << HPAGE_PMD_ORDER));
> +		} else {
> +			page = pfn_to_page(args->pmd_pfn);
> +			__free_pages(page, HPAGE_PMD_ORDER);
> +		}
> +
> +		args->pmd_pfn = ULONG_MAX;
> +		args->pte_pfn = ULONG_MAX;
> +	}
> +
> +	if (args->pte_pfn != ULONG_MAX) {
> +		page = pfn_to_page(args->pte_pfn);
> +		__free_pages(page, 0);

		args->pte_pfn = ULONG_MAX ?

> +	}
> +
> +	/* Free page table entries */
> +	if (args->start_ptep) {
> +		pte_free(args->mm, args->start_ptep);
> +		mm_dec_nr_ptes(args->mm);
> +	}
> +
> +	if (args->start_pmdp) {
> +		pmd_free(args->mm, args->start_pmdp);
> +		mm_dec_nr_pmds(args->mm);
> +	}
> +
> +	if (args->start_pudp) {
> +		pud_free(args->mm, args->start_pudp);
> +		mm_dec_nr_puds(args->mm);
> +	}
> +
> +	if (args->start_p4dp)
> +		p4d_free(args->mm, args->start_p4dp);
> +
> +	/* Free vma and mm struct */
> +	if (args->vma)
> +		vm_area_free(args->vma);
> +
> +	if (args->mm)
> +		mmdrop(args->mm);
> +}
> +
> +static struct page * __init debug_vm_pgtable_alloc_huge_page(
> +				struct pgtable_debug_args *args, int order)

Small nit, formatting like below would have been better. But dont change yet
unless there is a respin.

static struct page * __init
debug_vm_pgtable_alloc_huge_page(struct pgtable_debug_args *args, int order)

> +{
> +	struct page *page = NULL;
> +
> +#ifdef CONFIG_CONTIG_ALLOC
> +	if (order >= MAX_ORDER) {
> +		page = alloc_contig_pages((1 << order), GFP_KERNEL,
> +					  first_online_node, NULL);
> +		if (page) {
> +			args->is_contiguous_page = true;
> +			return page;
> +		}
> +	}
> +#endif
> +
> +	if (order < MAX_ORDER)
> +		page = alloc_pages(GFP_KERNEL, order);
> +
> +	return page;
> +}
> +
> +static int __init init_args(struct pgtable_debug_args *args)
> +{
> +	struct page *page = NULL;
> +	phys_addr_t phys;
> +	int ret = 0;
> +
> +	/*
> +	 * Initialize the debugging data.
> +	 *
> +	 * __P000 (or even __S000) will help create page table entries with
> +	 * PROT_NONE permission as required for pxx_protnone_tests().
> +	 */
> +	memset(args, 0, sizeof(*args));
> +	args->vaddr              = get_random_vaddr();
> +	args->page_prot          = vm_get_page_prot(VMFLAGS);
> +	args->page_prot_none     = __P000;
> +	args->is_contiguous_page = false;
> +	args->pud_pfn            = ULONG_MAX;
> +	args->pmd_pfn            = ULONG_MAX;
> +	args->pte_pfn            = ULONG_MAX;
> +	args->fixed_pgd_pfn      = ULONG_MAX;
> +	args->fixed_p4d_pfn      = ULONG_MAX;
> +	args->fixed_pud_pfn      = ULONG_MAX;
> +	args->fixed_pmd_pfn      = ULONG_MAX;
> +	args->fixed_pte_pfn      = ULONG_MAX;
> +
> +	/* Allocate mm and vma */
> +	args->mm = mm_alloc();
> +	if (!args->mm) {
> +		pr_err("Failed to allocate mm struct\n");
> +		ret = -ENOMEM;
> +		goto error;
> +	}
> +
> +	args->vma = vm_area_alloc(args->mm);
> +	if (!args->vma) {
> +		pr_err("Failed to allocate vma\n");
> +		ret = -ENOMEM;
> +		goto error;
> +	}
> +
> +	/*
> +	 * Allocate page table entries. They will be modified in the tests.
> +	 * Lets save the page table entries so that they can be released
> +	 * when the tests are completed.
> +	 */
> +	args->pgdp = pgd_offset(args->mm, args->vaddr);
> +	args->p4dp = p4d_alloc(args->mm, args->pgdp, args->vaddr);
> +	args->start_p4dp = p4d_offset(args->pgdp, 0UL);
> +	WARN_ON(!args->start_p4dp);
> +	if (!args->p4dp) {
> +		pr_err("Failed to allocate p4d entries\n");
> +		ret = -ENOMEM;
> +		goto error;
> +	}

Expected like this instead. 'args->start_p4dp' should not be evaluated
unless 'args->p4dp' allocation succeeds. Otherwise on the error path,
it would call p4d_free(args->mm, args->start_p4dp) freeing up a page
table page which was never allocated !

	args->pgdp = pgd_offset(args->mm, args->vaddr);
	args->p4dp = p4d_alloc(args->mm, args->pgdp, args->vaddr);
	if (!args->p4dp) {
		pr_err("Failed to allocate p4d entries\n");
		ret = -ENOMEM;
		goto error;
	}
	args->start_p4dp = p4d_offset(args->pgdp, 0UL);
	WARN_ON(!args->start_p4dp);

I had requested just to move these two sentences into the previous code
block, without changing any order. This is also applicable for all other
page table levels below.

> +
> +	args->pudp = pud_alloc(args->mm, args->p4dp, args->vaddr);
> +	args->start_pudp = pud_offset(args->p4dp, 0UL);
> +	WARN_ON(!args->start_pudp);
> +	if (!args->pudp) {
> +		pr_err("Failed to allocate pud entries\n");
> +		ret = -ENOMEM;
> +		goto error;
> +	}
> +
> +	args->pmdp = pmd_alloc(args->mm, args->pudp, args->vaddr);
> +	args->start_pmdp = pmd_offset(args->pudp, 0UL);
> +	WARN_ON(!args->start_pmdp);
> +	if (!args->pmdp) {
> +		pr_err("Failed to allocate pmd entries\n");
> +		ret = -ENOMEM;
> +		goto error;
> +	}
> +
> +	args->ptep = pte_alloc_map(args->mm, args->pmdp, args->vaddr);
> +	args->start_ptep = pmd_pgtable(READ_ONCE(*args->pmdp));
> +	WARN_ON(!args->start_ptep);
> +	if (!args->ptep) {
> +		pr_err("Failed to allocate pte entries\n");
> +		ret = -ENOMEM;
> +		goto error;
> +	}
> +
> +	/*
> +	 * PFN for mapping at PTE level is determined from a standard kernel
> +	 * text symbol. But pfns for higher page table levels are derived by
> +	 * masking lower bits of this real pfn. These derived pfns might not
> +	 * exist on the platform but that does not really matter as pfn_pxx()
> +	 * helpers will still create appropriate entries for the test. This
> +	 * helps avoid large memory block allocations to be used for mapping
> +	 * at higher page table levels in some of the tests.
> +	 */
> +	phys = __pa_symbol(&start_kernel);
> +	args->fixed_pgd_pfn = __phys_to_pfn(phys & PGDIR_MASK);
> +	args->fixed_p4d_pfn = __phys_to_pfn(phys & P4D_MASK);
> +	args->fixed_pud_pfn = __phys_to_pfn(phys & PUD_MASK);
> +	args->fixed_pmd_pfn = __phys_to_pfn(phys & PMD_MASK);
> +	args->fixed_pte_pfn = __phys_to_pfn(phys & PAGE_MASK);
> +	WARN_ON(!pfn_valid(args->fixed_pte_pfn));
> +
> +	/*
> +	 * Allocate (huge) pages because some of the tests need to access
> +	 * the data in the pages. The corresponding tests will be skipped
> +	 * if we fail to allocate (huge) pages.
> +	 */
> +	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
> +	    IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) &&
> +	    has_transparent_hugepage()) {
> +		page = debug_vm_pgtable_alloc_huge_page(args,
> +				HPAGE_PUD_SHIFT - PAGE_SHIFT);
> +		if (page) {
> +			args->pud_pfn = page_to_pfn(page);
> +			args->pmd_pfn = args->pud_pfn;
> +			args->pte_pfn = args->pud_pfn;
> +			return 0;
> +		}
> +	}
> +
> +	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
> +	    has_transparent_hugepage()) {
> +		page = debug_vm_pgtable_alloc_huge_page(args, HPAGE_PMD_ORDER);
> +		if (page) {
> +			args->pmd_pfn = page_to_pfn(page);
> +			args->pte_pfn = args->pmd_pfn;
> +			return 0;
> +		}
> +	}
> +
> +	page = alloc_pages(GFP_KERNEL, 0);
> +	if (page)
> +		args->pte_pfn = page_to_pfn(page);
> +
> +	return 0;
> +
> +error:
> +	destroy_args(args);
> +	return ret;
> +}
> +
>  static int __init debug_vm_pgtable(void)
>  {
> +	struct pgtable_debug_args args;
>  	struct vm_area_struct *vma;
>  	struct mm_struct *mm;
>  	pgd_t *pgdp;
> @@ -970,9 +1231,13 @@ static int __init debug_vm_pgtable(void)
>  	unsigned long vaddr, pte_aligned, pmd_aligned;
>  	unsigned long pud_aligned, p4d_aligned, pgd_aligned;
>  	spinlock_t *ptl = NULL;
> -	int idx;
> +	int idx, ret;
>  
>  	pr_info("Validating architecture page table helpers\n");
> +	ret = init_args(&args);
> +	if (ret)
> +		return ret;
> +
>  	prot = vm_get_page_prot(VMFLAGS);
>  	vaddr = get_random_vaddr();
>  	mm = mm_alloc();
> @@ -1127,6 +1392,8 @@ static int __init debug_vm_pgtable(void)
>  	mm_dec_nr_pmds(mm);
>  	mm_dec_nr_ptes(mm);
>  	mmdrop(mm);
> +
> +	destroy_args(&args);
>  	return 0;
>  }
>  late_initcall(debug_vm_pgtable);
> 

Re: [PATCH v5 01/12] mm/debug_vm_pgtable: Introduce struct pgtable_debug_args

[Gavin Shan]

Hi Anshuman,

On 8/3/21 2:42 PM, Anshuman Khandual wrote:
> On 8/2/21 11:34 AM, Gavin Shan wrote:
>> In debug_vm_pgtable(), there are many local variables introduced to
>> track the needed information and they are passed to the functions for
>> various test cases. It'd better to introduce a struct as place holder
>> for these information. With it, what the tests functions need is the
>> struct. In this way, the code is simplified and easier to be maintained.
>>
>> Besides, set_xxx_at() could access the data on the corresponding pages
>> in the page table modifying tests. So the accessed pages in the tests
>> should have been allocated from buddy. Otherwise, we're accessing pages
>> that aren't owned by us. This causes issues like page flag corruption
>> or kernel crash on accessing unmapped page when CONFIG_DEBUG_PAGEALLOC
>> is enabled.
>>
>> This introduces "struct pgtable_debug_args". The struct is initialized
>> and destroyed, but the information in the struct isn't used yet. It will
>> be used in subsequent patches.
>>
>> Signed-off-by: Gavin Shan <gshan@redhat.com>
>> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
>> ---
>>   mm/debug_vm_pgtable.c | 269 +++++++++++++++++++++++++++++++++++++++++-
>>   1 file changed, 268 insertions(+), 1 deletion(-)
>>
>> diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
>> index 1c922691aa61..6a825f0e7cd7 100644
>> --- a/mm/debug_vm_pgtable.c
>> +++ b/mm/debug_vm_pgtable.c
>> @@ -58,6 +58,37 @@
>>   #define RANDOM_ORVALUE (GENMASK(BITS_PER_LONG - 1, 0) & ~ARCH_SKIP_MASK)
>>   #define RANDOM_NZVALUE	GENMASK(7, 0)
>>   
>> +struct pgtable_debug_args {
>> +	struct mm_struct	*mm;
>> +	struct vm_area_struct	*vma;
>> +
>> +	pgd_t			*pgdp;
>> +	p4d_t			*p4dp;
>> +	pud_t			*pudp;
>> +	pmd_t			*pmdp;
>> +	pte_t			*ptep;
>> +
>> +	p4d_t			*start_p4dp;
>> +	pud_t			*start_pudp;
>> +	pmd_t			*start_pmdp;
>> +	pgtable_t		start_ptep;
>> +
>> +	unsigned long		vaddr;
>> +	pgprot_t		page_prot;
>> +	pgprot_t		page_prot_none;
>> +
>> +	bool			is_contiguous_page;
>> +	unsigned long		pud_pfn;
>> +	unsigned long		pmd_pfn;
>> +	unsigned long		pte_pfn;
>> +
>> +	unsigned long		fixed_pgd_pfn;
>> +	unsigned long		fixed_p4d_pfn;
>> +	unsigned long		fixed_pud_pfn;
>> +	unsigned long		fixed_pmd_pfn;
>> +	unsigned long		fixed_pte_pfn;
>> +};
>> +
>>   static void __init pte_basic_tests(unsigned long pfn, int idx)
>>   {
>>   	pgprot_t prot = protection_map[idx];
>> @@ -955,8 +986,238 @@ static unsigned long __init get_random_vaddr(void)
>>   	return random_vaddr;
>>   }
>>   
>> +static void __init destroy_args(struct pgtable_debug_args *args)
>> +{
>> +	struct page *page = NULL;
>> +
>> +	/* Free (huge) page */
>> +	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
>> +	    IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) &&
>> +	    has_transparent_hugepage() &&
>> +	    args->pud_pfn != ULONG_MAX) {
>> +		if (args->is_contiguous_page) {
>> +			free_contig_range(args->pud_pfn,
>> +					  (1 << (HPAGE_PUD_SHIFT - PAGE_SHIFT)));
>> +		} else {
>> +			page = pfn_to_page(args->pud_pfn);
>> +			__free_pages(page, HPAGE_PUD_SHIFT - PAGE_SHIFT);
>> +		}
>> +
>> +		args->pud_pfn = ULONG_MAX;
>> +		args->pmd_pfn = ULONG_MAX;
>> +		args->pte_pfn = ULONG_MAX;
>> +	}
>> +
>> +	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
>> +	    has_transparent_hugepage() &&
>> +	    args->pmd_pfn != ULONG_MAX) {
>> +		if (args->is_contiguous_page) {
>> +			free_contig_range(args->pmd_pfn, (1 << HPAGE_PMD_ORDER));
>> +		} else {
>> +			page = pfn_to_page(args->pmd_pfn);
>> +			__free_pages(page, HPAGE_PMD_ORDER);
>> +		}
>> +
>> +		args->pmd_pfn = ULONG_MAX;
>> +		args->pte_pfn = ULONG_MAX;
>> +	}
>> +
>> +	if (args->pte_pfn != ULONG_MAX) {
>> +		page = pfn_to_page(args->pte_pfn);
>> +		__free_pages(page, 0);
> 
> 		args->pte_pfn = ULONG_MAX ?
> 

I was thinking of this. It doesn't matter to set @pte_pfn to
ULONG_MAX as it's not used afterwards. However, I will add this
in v6 for consistency.

>> +	}
>> +
>> +	/* Free page table entries */
>> +	if (args->start_ptep) {
>> +		pte_free(args->mm, args->start_ptep);
>> +		mm_dec_nr_ptes(args->mm);
>> +	}
>> +
>> +	if (args->start_pmdp) {
>> +		pmd_free(args->mm, args->start_pmdp);
>> +		mm_dec_nr_pmds(args->mm);
>> +	}
>> +
>> +	if (args->start_pudp) {
>> +		pud_free(args->mm, args->start_pudp);
>> +		mm_dec_nr_puds(args->mm);
>> +	}
>> +
>> +	if (args->start_p4dp)
>> +		p4d_free(args->mm, args->start_p4dp);
>> +
>> +	/* Free vma and mm struct */
>> +	if (args->vma)
>> +		vm_area_free(args->vma);
>> +
>> +	if (args->mm)
>> +		mmdrop(args->mm);
>> +}
>> +
>> +static struct page * __init debug_vm_pgtable_alloc_huge_page(
>> +				struct pgtable_debug_args *args, int order)
> 
> Small nit, formatting like below would have been better. But dont change yet
> unless there is a respin.
> 

Yes, will fix in v6.

> static struct page * __init
> debug_vm_pgtable_alloc_huge_page(struct pgtable_debug_args *args, int order)
> 
>> +{
>> +	struct page *page = NULL;
>> +
>> +#ifdef CONFIG_CONTIG_ALLOC
>> +	if (order >= MAX_ORDER) {
>> +		page = alloc_contig_pages((1 << order), GFP_KERNEL,
>> +					  first_online_node, NULL);
>> +		if (page) {
>> +			args->is_contiguous_page = true;
>> +			return page;
>> +		}
>> +	}
>> +#endif
>> +
>> +	if (order < MAX_ORDER)
>> +		page = alloc_pages(GFP_KERNEL, order);
>> +
>> +	return page;
>> +}
>> +
>> +static int __init init_args(struct pgtable_debug_args *args)
>> +{
>> +	struct page *page = NULL;
>> +	phys_addr_t phys;
>> +	int ret = 0;
>> +
>> +	/*
>> +	 * Initialize the debugging data.
>> +	 *
>> +	 * __P000 (or even __S000) will help create page table entries with
>> +	 * PROT_NONE permission as required for pxx_protnone_tests().
>> +	 */
>> +	memset(args, 0, sizeof(*args));
>> +	args->vaddr              = get_random_vaddr();
>> +	args->page_prot          = vm_get_page_prot(VMFLAGS);
>> +	args->page_prot_none     = __P000;
>> +	args->is_contiguous_page = false;
>> +	args->pud_pfn            = ULONG_MAX;
>> +	args->pmd_pfn            = ULONG_MAX;
>> +	args->pte_pfn            = ULONG_MAX;
>> +	args->fixed_pgd_pfn      = ULONG_MAX;
>> +	args->fixed_p4d_pfn      = ULONG_MAX;
>> +	args->fixed_pud_pfn      = ULONG_MAX;
>> +	args->fixed_pmd_pfn      = ULONG_MAX;
>> +	args->fixed_pte_pfn      = ULONG_MAX;
>> +
>> +	/* Allocate mm and vma */
>> +	args->mm = mm_alloc();
>> +	if (!args->mm) {
>> +		pr_err("Failed to allocate mm struct\n");
>> +		ret = -ENOMEM;
>> +		goto error;
>> +	}
>> +
>> +	args->vma = vm_area_alloc(args->mm);
>> +	if (!args->vma) {
>> +		pr_err("Failed to allocate vma\n");
>> +		ret = -ENOMEM;
>> +		goto error;
>> +	}
>> +
>> +	/*
>> +	 * Allocate page table entries. They will be modified in the tests.
>> +	 * Lets save the page table entries so that they can be released
>> +	 * when the tests are completed.
>> +	 */
>> +	args->pgdp = pgd_offset(args->mm, args->vaddr);
>> +	args->p4dp = p4d_alloc(args->mm, args->pgdp, args->vaddr);
>> +	args->start_p4dp = p4d_offset(args->pgdp, 0UL);
>> +	WARN_ON(!args->start_p4dp);
>> +	if (!args->p4dp) {
>> +		pr_err("Failed to allocate p4d entries\n");
>> +		ret = -ENOMEM;
>> +		goto error;
>> +	}
> 
> Expected like this instead. 'args->start_p4dp' should not be evaluated
> unless 'args->p4dp' allocation succeeds. Otherwise on the error path,
> it would call p4d_free(args->mm, args->start_p4dp) freeing up a page
> table page which was never allocated !
> 
> 	args->pgdp = pgd_offset(args->mm, args->vaddr);
> 	args->p4dp = p4d_alloc(args->mm, args->pgdp, args->vaddr);
> 	if (!args->p4dp) {
> 		pr_err("Failed to allocate p4d entries\n");
> 		ret = -ENOMEM;
> 		goto error;
> 	}
> 	args->start_p4dp = p4d_offset(args->pgdp, 0UL);
> 	WARN_ON(!args->start_p4dp);
> 
> I had requested just to move these two sentences into the previous code
> block, without changing any order. This is also applicable for all other
> page table levels below.
> 

Yeah, I misunderstood your comments on v5 series. I wrongly thought
NULL is returned from p4d_offset() if p4d_alloc() fails, without
checking the implementation of p4d_offset() closely. I will fix
it in v6. However, I will hold posting v6 to see if there are
more comments on v5.

>> +
>> +	args->pudp = pud_alloc(args->mm, args->p4dp, args->vaddr);
>> +	args->start_pudp = pud_offset(args->p4dp, 0UL);
>> +	WARN_ON(!args->start_pudp);
>> +	if (!args->pudp) {
>> +		pr_err("Failed to allocate pud entries\n");
>> +		ret = -ENOMEM;
>> +		goto error;
>> +	}
>> +
>> +	args->pmdp = pmd_alloc(args->mm, args->pudp, args->vaddr);
>> +	args->start_pmdp = pmd_offset(args->pudp, 0UL);
>> +	WARN_ON(!args->start_pmdp);
>> +	if (!args->pmdp) {
>> +		pr_err("Failed to allocate pmd entries\n");
>> +		ret = -ENOMEM;
>> +		goto error;
>> +	}
>> +
>> +	args->ptep = pte_alloc_map(args->mm, args->pmdp, args->vaddr);
>> +	args->start_ptep = pmd_pgtable(READ_ONCE(*args->pmdp));
>> +	WARN_ON(!args->start_ptep);
>> +	if (!args->ptep) {
>> +		pr_err("Failed to allocate pte entries\n");
>> +		ret = -ENOMEM;
>> +		goto error;
>> +	}
>> +
>> +	/*
>> +	 * PFN for mapping at PTE level is determined from a standard kernel
>> +	 * text symbol. But pfns for higher page table levels are derived by
>> +	 * masking lower bits of this real pfn. These derived pfns might not
>> +	 * exist on the platform but that does not really matter as pfn_pxx()
>> +	 * helpers will still create appropriate entries for the test. This
>> +	 * helps avoid large memory block allocations to be used for mapping
>> +	 * at higher page table levels in some of the tests.
>> +	 */
>> +	phys = __pa_symbol(&start_kernel);
>> +	args->fixed_pgd_pfn = __phys_to_pfn(phys & PGDIR_MASK);
>> +	args->fixed_p4d_pfn = __phys_to_pfn(phys & P4D_MASK);
>> +	args->fixed_pud_pfn = __phys_to_pfn(phys & PUD_MASK);
>> +	args->fixed_pmd_pfn = __phys_to_pfn(phys & PMD_MASK);
>> +	args->fixed_pte_pfn = __phys_to_pfn(phys & PAGE_MASK);
>> +	WARN_ON(!pfn_valid(args->fixed_pte_pfn));
>> +
>> +	/*
>> +	 * Allocate (huge) pages because some of the tests need to access
>> +	 * the data in the pages. The corresponding tests will be skipped
>> +	 * if we fail to allocate (huge) pages.
>> +	 */
>> +	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
>> +	    IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) &&
>> +	    has_transparent_hugepage()) {
>> +		page = debug_vm_pgtable_alloc_huge_page(args,
>> +				HPAGE_PUD_SHIFT - PAGE_SHIFT);
>> +		if (page) {
>> +			args->pud_pfn = page_to_pfn(page);
>> +			args->pmd_pfn = args->pud_pfn;
>> +			args->pte_pfn = args->pud_pfn;
>> +			return 0;
>> +		}
>> +	}
>> +
>> +	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
>> +	    has_transparent_hugepage()) {
>> +		page = debug_vm_pgtable_alloc_huge_page(args, HPAGE_PMD_ORDER);
>> +		if (page) {
>> +			args->pmd_pfn = page_to_pfn(page);
>> +			args->pte_pfn = args->pmd_pfn;
>> +			return 0;
>> +		}
>> +	}
>> +
>> +	page = alloc_pages(GFP_KERNEL, 0);
>> +	if (page)
>> +		args->pte_pfn = page_to_pfn(page);
>> +
>> +	return 0;
>> +
>> +error:
>> +	destroy_args(args);
>> +	return ret;
>> +}
>> +
>>   static int __init debug_vm_pgtable(void)
>>   {
>> +	struct pgtable_debug_args args;
>>   	struct vm_area_struct *vma;
>>   	struct mm_struct *mm;
>>   	pgd_t *pgdp;
>> @@ -970,9 +1231,13 @@ static int __init debug_vm_pgtable(void)
>>   	unsigned long vaddr, pte_aligned, pmd_aligned;
>>   	unsigned long pud_aligned, p4d_aligned, pgd_aligned;
>>   	spinlock_t *ptl = NULL;
>> -	int idx;
>> +	int idx, ret;
>>   
>>   	pr_info("Validating architecture page table helpers\n");
>> +	ret = init_args(&args);
>> +	if (ret)
>> +		return ret;
>> +
>>   	prot = vm_get_page_prot(VMFLAGS);
>>   	vaddr = get_random_vaddr();
>>   	mm = mm_alloc();
>> @@ -1127,6 +1392,8 @@ static int __init debug_vm_pgtable(void)
>>   	mm_dec_nr_pmds(mm);
>>   	mm_dec_nr_ptes(mm);
>>   	mmdrop(mm);
>> +
>> +	destroy_args(&args);
>>   	return 0;
>>   }
>>   late_initcall(debug_vm_pgtable);
>>

Thanks,
Gavin

Re: [PATCH v5 00/12] mm/debug_vm_pgtable: Enhancements

[Anshuman Khandual]

On 8/2/21 11:34 AM, Gavin Shan wrote:
> There are couple of issues with current implementations and this series
> tries to resolve the issues:
> 
>   (a) All needed information are scattered in variables, passed to various
>       test functions. The code is organized in pretty much relaxed fashion.
> 
>   (b) The page isn't allocated from buddy during page table entry modifying
>       tests. The page can be invalid, conflicting to the implementations
>       of set_xxx_at() on ARM64. The target page is accessed so that the
>       iCache can be flushed when execution permission is given on ARM64.
>       Besides, the target page can be unmapped and accessing to it causes
>       kernel crash.
> 
> "struct pgtable_debug_args" is introduced to address issue (a). For issue
> (b), the used page is allocated from buddy in page table entry modifying
> tests. The corresponding tets will be skipped if we fail to allocate the
> (huge) page. For other test cases, the original page around to kernel
> symbol (@start_kernel) is still used.
> 
> The patches are organized as below. PATCH[2-10] could be combined to one
> patch, but it will make the review harder:
> 
>   PATCH[1] introduces "struct pgtable_debug_args" as place holder of all
>            needed information. With it, the old and new implementation
>            can coexist.
>   PATCH[2-10] uses "struct pgtable_debug_args" in various test functions.
>   PATCH[11] removes the unused code for old implementation.
>   PATCH[12] fixes the issue of corrupted page flag for ARM64
> 
> Changelog
> =========
> v5:
>    * Pick r-bs from Anshuman and rebase to 5.14.rc4          (Gavin)
>    * Use args->start_p4dp to free p4d entries                (Anshuman)
>    * Introduce helper to allocate huge page in init_arg()    (Anshuman)
>    * Bail early if the allocated page doesn't exist in
>      swap_migration_tests() and correct the comments         (Anshuman)
>    * Add fixes tag to PATCH[v4 12/12]                        (Christophe)
>    * Address misc comments                                   (Anshuman)

Apart from the proposed changes discussed for the first patch [PATCH 1/12],
this series overall looks good now. It clears build tests on all supported
platforms. I was able to test this on arm64 and x86 platforms with various
functional config combinations. It would be still great if others can take
a look as well.

- Anshuman