debug_vm_pgtable.c 30.5 KB
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// SPDX-License-Identifier: GPL-2.0-only
/*
 * This kernel test validates architecture page table helpers and
 * accessors and helps in verifying their continued compliance with
 * expected generic MM semantics.
 *
 * Copyright (C) 2019 ARM Ltd.
 *
 * Author: Anshuman Khandual <anshuman.khandual@arm.com>
 */
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#define pr_fmt(fmt) "debug_vm_pgtable: [%-25s]: " fmt, __func__
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#include <linux/gfp.h>
#include <linux/highmem.h>
#include <linux/hugetlb.h>
#include <linux/kernel.h>
#include <linux/kconfig.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/mm_types.h>
#include <linux/module.h>
#include <linux/pfn_t.h>
#include <linux/printk.h>
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#include <linux/pgtable.h>
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#include <linux/random.h>
#include <linux/spinlock.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/start_kernel.h>
#include <linux/sched/mm.h>
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#include <linux/io.h>
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#include <asm/pgalloc.h>
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#include <asm/tlbflush.h>
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/*
 * Please refer Documentation/vm/arch_pgtable_helpers.rst for the semantics
 * expectations that are being validated here. All future changes in here
 * or the documentation need to be in sync.
 */

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#define VMFLAGS	(VM_READ|VM_WRITE|VM_EXEC)

/*
 * On s390 platform, the lower 4 bits are used to identify given page table
 * entry type. But these bits might affect the ability to clear entries with
 * pxx_clear() because of how dynamic page table folding works on s390. So
 * while loading up the entries do not change the lower 4 bits. It does not
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 * have affect any other platform. Also avoid the 62nd bit on ppc64 that is
 * used to mark a pte entry.
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 */
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#define S390_SKIP_MASK		GENMASK(3, 0)
#if __BITS_PER_LONG == 64
#define PPC64_SKIP_MASK		GENMASK(62, 62)
#else
#define PPC64_SKIP_MASK		0x0
#endif
#define ARCH_SKIP_MASK (S390_SKIP_MASK | PPC64_SKIP_MASK)
#define RANDOM_ORVALUE (GENMASK(BITS_PER_LONG - 1, 0) & ~ARCH_SKIP_MASK)
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#define RANDOM_NZVALUE	GENMASK(7, 0)

static void __init pte_basic_tests(unsigned long pfn, pgprot_t prot)
{
	pte_t pte = pfn_pte(pfn, prot);

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	pr_debug("Validating PTE basic\n");
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	/*
	 * This test needs to be executed after the given page table entry
	 * is created with pfn_pte() to make sure that protection_map[idx]
	 * does not have the dirty bit enabled from the beginning. This is
	 * important for platforms like arm64 where (!PTE_RDONLY) indicate
	 * dirty bit being set.
	 */
	WARN_ON(pte_dirty(pte_wrprotect(pte)));

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	WARN_ON(!pte_same(pte, pte));
	WARN_ON(!pte_young(pte_mkyoung(pte_mkold(pte))));
	WARN_ON(!pte_dirty(pte_mkdirty(pte_mkclean(pte))));
	WARN_ON(!pte_write(pte_mkwrite(pte_wrprotect(pte))));
	WARN_ON(pte_young(pte_mkold(pte_mkyoung(pte))));
	WARN_ON(pte_dirty(pte_mkclean(pte_mkdirty(pte))));
	WARN_ON(pte_write(pte_wrprotect(pte_mkwrite(pte))));
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	WARN_ON(pte_dirty(pte_wrprotect(pte_mkclean(pte))));
	WARN_ON(!pte_dirty(pte_wrprotect(pte_mkdirty(pte))));
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}

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static void __init pte_advanced_tests(struct mm_struct *mm,
				      struct vm_area_struct *vma, pte_t *ptep,
				      unsigned long pfn, unsigned long vaddr,
				      pgprot_t prot)
{
	pte_t pte = pfn_pte(pfn, prot);

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	/*
	 * 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
	 */

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	pr_debug("Validating PTE advanced\n");
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	pte = pfn_pte(pfn, prot);
	set_pte_at(mm, vaddr, ptep, pte);
	ptep_set_wrprotect(mm, vaddr, ptep);
	pte = ptep_get(ptep);
	WARN_ON(pte_write(pte));
	ptep_get_and_clear(mm, vaddr, ptep);
	pte = ptep_get(ptep);
	WARN_ON(!pte_none(pte));

	pte = pfn_pte(pfn, prot);
	pte = pte_wrprotect(pte);
	pte = pte_mkclean(pte);
	set_pte_at(mm, vaddr, ptep, pte);
	pte = pte_mkwrite(pte);
	pte = pte_mkdirty(pte);
	ptep_set_access_flags(vma, vaddr, ptep, pte, 1);
	pte = ptep_get(ptep);
	WARN_ON(!(pte_write(pte) && pte_dirty(pte)));
	ptep_get_and_clear_full(mm, vaddr, ptep, 1);
	pte = ptep_get(ptep);
	WARN_ON(!pte_none(pte));

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	pte = pfn_pte(pfn, prot);
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	pte = pte_mkyoung(pte);
	set_pte_at(mm, vaddr, ptep, pte);
	ptep_test_and_clear_young(vma, vaddr, ptep);
	pte = ptep_get(ptep);
	WARN_ON(pte_young(pte));
}

static void __init pte_savedwrite_tests(unsigned long pfn, pgprot_t prot)
{
	pte_t pte = pfn_pte(pfn, prot);

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	if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
		return;

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	pr_debug("Validating PTE saved write\n");
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	WARN_ON(!pte_savedwrite(pte_mk_savedwrite(pte_clear_savedwrite(pte))));
	WARN_ON(pte_savedwrite(pte_clear_savedwrite(pte_mk_savedwrite(pte))));
}
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#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot)
{
	pmd_t pmd = pfn_pmd(pfn, prot);

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	if (!has_transparent_hugepage())
		return;

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	pr_debug("Validating PMD basic\n");
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	/*
	 * This test needs to be executed after the given page table entry
	 * is created with pfn_pmd() to make sure that protection_map[idx]
	 * does not have the dirty bit enabled from the beginning. This is
	 * important for platforms like arm64 where (!PTE_RDONLY) indicate
	 * dirty bit being set.
	 */
	WARN_ON(pmd_dirty(pmd_wrprotect(pmd)));


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	WARN_ON(!pmd_same(pmd, pmd));
	WARN_ON(!pmd_young(pmd_mkyoung(pmd_mkold(pmd))));
	WARN_ON(!pmd_dirty(pmd_mkdirty(pmd_mkclean(pmd))));
	WARN_ON(!pmd_write(pmd_mkwrite(pmd_wrprotect(pmd))));
	WARN_ON(pmd_young(pmd_mkold(pmd_mkyoung(pmd))));
	WARN_ON(pmd_dirty(pmd_mkclean(pmd_mkdirty(pmd))));
	WARN_ON(pmd_write(pmd_wrprotect(pmd_mkwrite(pmd))));
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	WARN_ON(pmd_dirty(pmd_wrprotect(pmd_mkclean(pmd))));
	WARN_ON(!pmd_dirty(pmd_wrprotect(pmd_mkdirty(pmd))));
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	/*
	 * A huge page does not point to next level page table
	 * entry. Hence this must qualify as pmd_bad().
	 */
	WARN_ON(!pmd_bad(pmd_mkhuge(pmd)));
}

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static void __init pmd_advanced_tests(struct mm_struct *mm,
				      struct vm_area_struct *vma, pmd_t *pmdp,
				      unsigned long pfn, unsigned long vaddr,
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				      pgprot_t prot, pgtable_t pgtable)
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{
	pmd_t pmd = pfn_pmd(pfn, prot);

	if (!has_transparent_hugepage())
		return;

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	pr_debug("Validating PMD advanced\n");
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	/* Align the address wrt HPAGE_PMD_SIZE */
	vaddr = (vaddr & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE;

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	pgtable_trans_huge_deposit(mm, pmdp, pgtable);

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	pmd = pfn_pmd(pfn, prot);
	set_pmd_at(mm, vaddr, pmdp, pmd);
	pmdp_set_wrprotect(mm, vaddr, pmdp);
	pmd = READ_ONCE(*pmdp);
	WARN_ON(pmd_write(pmd));
	pmdp_huge_get_and_clear(mm, vaddr, pmdp);
	pmd = READ_ONCE(*pmdp);
	WARN_ON(!pmd_none(pmd));

	pmd = pfn_pmd(pfn, prot);
	pmd = pmd_wrprotect(pmd);
	pmd = pmd_mkclean(pmd);
	set_pmd_at(mm, vaddr, pmdp, pmd);
	pmd = pmd_mkwrite(pmd);
	pmd = pmd_mkdirty(pmd);
	pmdp_set_access_flags(vma, vaddr, pmdp, pmd, 1);
	pmd = READ_ONCE(*pmdp);
	WARN_ON(!(pmd_write(pmd) && pmd_dirty(pmd)));
	pmdp_huge_get_and_clear_full(vma, vaddr, pmdp, 1);
	pmd = READ_ONCE(*pmdp);
	WARN_ON(!pmd_none(pmd));

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	pmd = pmd_mkhuge(pfn_pmd(pfn, prot));
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	pmd = pmd_mkyoung(pmd);
	set_pmd_at(mm, vaddr, pmdp, pmd);
	pmdp_test_and_clear_young(vma, vaddr, pmdp);
	pmd = READ_ONCE(*pmdp);
	WARN_ON(pmd_young(pmd));
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	/*  Clear the pte entries  */
	pmdp_huge_get_and_clear(mm, vaddr, pmdp);
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	pgtable = pgtable_trans_huge_withdraw(mm, pmdp);
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}

static void __init pmd_leaf_tests(unsigned long pfn, pgprot_t prot)
{
	pmd_t pmd = pfn_pmd(pfn, prot);

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	pr_debug("Validating PMD leaf\n");
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	/*
	 * PMD based THP is a leaf entry.
	 */
	pmd = pmd_mkhuge(pmd);
	WARN_ON(!pmd_leaf(pmd));
}

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#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
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static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot)
{
	pmd_t pmd;

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	if (!arch_ioremap_pmd_supported())
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		return;
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	pr_debug("Validating PMD huge\n");
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	/*
	 * X86 defined pmd_set_huge() verifies that the given
	 * PMD is not a populated non-leaf entry.
	 */
	WRITE_ONCE(*pmdp, __pmd(0));
	WARN_ON(!pmd_set_huge(pmdp, __pfn_to_phys(pfn), prot));
	WARN_ON(!pmd_clear_huge(pmdp));
	pmd = READ_ONCE(*pmdp);
	WARN_ON(!pmd_none(pmd));
}
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#else /* CONFIG_HAVE_ARCH_HUGE_VMAP */
static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot) { }
#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
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static void __init pmd_savedwrite_tests(unsigned long pfn, pgprot_t prot)
{
	pmd_t pmd = pfn_pmd(pfn, prot);

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	if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
		return;

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	pr_debug("Validating PMD saved write\n");
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	WARN_ON(!pmd_savedwrite(pmd_mk_savedwrite(pmd_clear_savedwrite(pmd))));
	WARN_ON(pmd_savedwrite(pmd_clear_savedwrite(pmd_mk_savedwrite(pmd))));
}

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#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot)
{
	pud_t pud = pfn_pud(pfn, prot);

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	if (!has_transparent_hugepage())
		return;

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	pr_debug("Validating PUD basic\n");
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	/*
	 * This test needs to be executed after the given page table entry
	 * is created with pfn_pud() to make sure that protection_map[idx]
	 * does not have the dirty bit enabled from the beginning. This is
	 * important for platforms like arm64 where (!PTE_RDONLY) indicate
	 * dirty bit being set.
	 */
	WARN_ON(pud_dirty(pud_wrprotect(pud)));

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	WARN_ON(!pud_same(pud, pud));
	WARN_ON(!pud_young(pud_mkyoung(pud_mkold(pud))));
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	WARN_ON(!pud_dirty(pud_mkdirty(pud_mkclean(pud))));
	WARN_ON(pud_dirty(pud_mkclean(pud_mkdirty(pud))));
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	WARN_ON(!pud_write(pud_mkwrite(pud_wrprotect(pud))));
	WARN_ON(pud_write(pud_wrprotect(pud_mkwrite(pud))));
	WARN_ON(pud_young(pud_mkold(pud_mkyoung(pud))));
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	WARN_ON(pud_dirty(pud_wrprotect(pud_mkclean(pud))));
	WARN_ON(!pud_dirty(pud_wrprotect(pud_mkdirty(pud))));
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	if (mm_pmd_folded(mm))
		return;

	/*
	 * A huge page does not point to next level page table
	 * entry. Hence this must qualify as pud_bad().
	 */
	WARN_ON(!pud_bad(pud_mkhuge(pud)));
}
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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)
{
	pud_t pud = pfn_pud(pfn, prot);

	if (!has_transparent_hugepage())
		return;

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	pr_debug("Validating PUD advanced\n");
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	/* Align the address wrt HPAGE_PUD_SIZE */
	vaddr = (vaddr & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE;

	set_pud_at(mm, vaddr, pudp, pud);
	pudp_set_wrprotect(mm, vaddr, pudp);
	pud = READ_ONCE(*pudp);
	WARN_ON(pud_write(pud));

#ifndef __PAGETABLE_PMD_FOLDED
	pudp_huge_get_and_clear(mm, vaddr, pudp);
	pud = READ_ONCE(*pudp);
	WARN_ON(!pud_none(pud));
#endif /* __PAGETABLE_PMD_FOLDED */
	pud = pfn_pud(pfn, prot);
	pud = pud_wrprotect(pud);
	pud = pud_mkclean(pud);
	set_pud_at(mm, vaddr, pudp, pud);
	pud = pud_mkwrite(pud);
	pud = pud_mkdirty(pud);
	pudp_set_access_flags(vma, vaddr, pudp, pud, 1);
	pud = READ_ONCE(*pudp);
	WARN_ON(!(pud_write(pud) && pud_dirty(pud)));

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#ifndef __PAGETABLE_PMD_FOLDED
	pudp_huge_get_and_clear_full(mm, vaddr, pudp, 1);
	pud = READ_ONCE(*pudp);
	WARN_ON(!pud_none(pud));
#endif /* __PAGETABLE_PMD_FOLDED */

	pud = pfn_pud(pfn, prot);
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	pud = pud_mkyoung(pud);
	set_pud_at(mm, vaddr, pudp, pud);
	pudp_test_and_clear_young(vma, vaddr, pudp);
	pud = READ_ONCE(*pudp);
	WARN_ON(pud_young(pud));
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	pudp_huge_get_and_clear(mm, vaddr, pudp);
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}

static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot)
{
	pud_t pud = pfn_pud(pfn, prot);

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	pr_debug("Validating PUD leaf\n");
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	/*
	 * PUD based THP is a leaf entry.
	 */
	pud = pud_mkhuge(pud);
	WARN_ON(!pud_leaf(pud));
}

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#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
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static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
{
	pud_t pud;

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	if (!arch_ioremap_pud_supported())
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		return;
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	pr_debug("Validating PUD huge\n");
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	/*
	 * X86 defined pud_set_huge() verifies that the given
	 * PUD is not a populated non-leaf entry.
	 */
	WRITE_ONCE(*pudp, __pud(0));
	WARN_ON(!pud_set_huge(pudp, __pfn_to_phys(pfn), prot));
	WARN_ON(!pud_clear_huge(pudp));
	pud = READ_ONCE(*pudp);
	WARN_ON(!pud_none(pud));
}
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#else /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot) { }
#endif /* !CONFIG_HAVE_ARCH_HUGE_VMAP */

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#else  /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot) { }
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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_leaf_tests(unsigned long pfn, pgprot_t prot) { }
static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
{
}
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#endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
#else  /* !CONFIG_TRANSPARENT_HUGEPAGE */
static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot) { }
static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot) { }
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static void __init pmd_advanced_tests(struct mm_struct *mm,
				      struct vm_area_struct *vma, pmd_t *pmdp,
				      unsigned long pfn, unsigned long vaddr,
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				      pgprot_t prot, pgtable_t pgtable)
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{
}
static void __init pud_advanced_tests(struct mm_struct *mm,
				      struct vm_area_struct *vma, pud_t *pudp,
				      unsigned long pfn, unsigned long vaddr,
				      pgprot_t prot)
{
}
static void __init pmd_leaf_tests(unsigned long pfn, pgprot_t prot) { }
static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot) { }
static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot)
{
}
static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
{
}
static void __init pmd_savedwrite_tests(unsigned long pfn, pgprot_t prot) { }
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#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

static void __init p4d_basic_tests(unsigned long pfn, pgprot_t prot)
{
	p4d_t p4d;

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	pr_debug("Validating P4D basic\n");
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	memset(&p4d, RANDOM_NZVALUE, sizeof(p4d_t));
	WARN_ON(!p4d_same(p4d, p4d));
}

static void __init pgd_basic_tests(unsigned long pfn, pgprot_t prot)
{
	pgd_t pgd;

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	pr_debug("Validating PGD basic\n");
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	memset(&pgd, RANDOM_NZVALUE, sizeof(pgd_t));
	WARN_ON(!pgd_same(pgd, pgd));
}

#ifndef __PAGETABLE_PUD_FOLDED
static void __init pud_clear_tests(struct mm_struct *mm, pud_t *pudp)
{
	pud_t pud = READ_ONCE(*pudp);

	if (mm_pmd_folded(mm))
		return;

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	pr_debug("Validating PUD clear\n");
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	pud = __pud(pud_val(pud) | RANDOM_ORVALUE);
	WRITE_ONCE(*pudp, pud);
	pud_clear(pudp);
	pud = READ_ONCE(*pudp);
	WARN_ON(!pud_none(pud));
}

static void __init pud_populate_tests(struct mm_struct *mm, pud_t *pudp,
				      pmd_t *pmdp)
{
	pud_t pud;

	if (mm_pmd_folded(mm))
		return;
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	pr_debug("Validating PUD populate\n");
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	/*
	 * 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);
	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)
{
}
#endif /* PAGETABLE_PUD_FOLDED */

#ifndef __PAGETABLE_P4D_FOLDED
static void __init p4d_clear_tests(struct mm_struct *mm, p4d_t *p4dp)
{
	p4d_t p4d = READ_ONCE(*p4dp);

	if (mm_pud_folded(mm))
		return;

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	pr_debug("Validating P4D clear\n");
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	p4d = __p4d(p4d_val(p4d) | RANDOM_ORVALUE);
	WRITE_ONCE(*p4dp, p4d);
	p4d_clear(p4dp);
	p4d = READ_ONCE(*p4dp);
	WARN_ON(!p4d_none(p4d));
}

static void __init p4d_populate_tests(struct mm_struct *mm, p4d_t *p4dp,
				      pud_t *pudp)
{
	p4d_t p4d;

	if (mm_pud_folded(mm))
		return;

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	pr_debug("Validating P4D populate\n");
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	/*
	 * 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);
	WARN_ON(p4d_bad(p4d));
}

static void __init pgd_clear_tests(struct mm_struct *mm, pgd_t *pgdp)
{
	pgd_t pgd = READ_ONCE(*pgdp);

	if (mm_p4d_folded(mm))
		return;

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	pr_debug("Validating PGD clear\n");
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	pgd = __pgd(pgd_val(pgd) | RANDOM_ORVALUE);
	WRITE_ONCE(*pgdp, pgd);
	pgd_clear(pgdp);
	pgd = READ_ONCE(*pgdp);
	WARN_ON(!pgd_none(pgd));
}

static void __init pgd_populate_tests(struct mm_struct *mm, pgd_t *pgdp,
				      p4d_t *p4dp)
{
	pgd_t pgd;

	if (mm_p4d_folded(mm))
		return;

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	pr_debug("Validating PGD populate\n");
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	/*
	 * 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);
	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)
{
}
#endif /* PAGETABLE_P4D_FOLDED */

static void __init pte_clear_tests(struct mm_struct *mm, pte_t *ptep,
582 583
				   unsigned long pfn, unsigned long vaddr,
				   pgprot_t prot)
584
{
585
	pte_t pte = pfn_pte(pfn, prot);
586

587
	pr_debug("Validating PTE clear\n");
588
#ifndef CONFIG_RISCV
589
	pte = __pte(pte_val(pte) | RANDOM_ORVALUE);
590
#endif
591 592 593
	set_pte_at(mm, vaddr, ptep, pte);
	barrier();
	pte_clear(mm, vaddr, ptep);
594
	pte = ptep_get(ptep);
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	WARN_ON(!pte_none(pte));
}

static void __init pmd_clear_tests(struct mm_struct *mm, pmd_t *pmdp)
{
	pmd_t pmd = READ_ONCE(*pmdp);

602
	pr_debug("Validating PMD clear\n");
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	pmd = __pmd(pmd_val(pmd) | RANDOM_ORVALUE);
	WRITE_ONCE(*pmdp, pmd);
	pmd_clear(pmdp);
	pmd = READ_ONCE(*pmdp);
	WARN_ON(!pmd_none(pmd));
}

static void __init pmd_populate_tests(struct mm_struct *mm, pmd_t *pmdp,
				      pgtable_t pgtable)
{
	pmd_t pmd;

615
	pr_debug("Validating PMD populate\n");
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	/*
	 * 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);
	WARN_ON(pmd_bad(pmd));
}

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static void __init pte_special_tests(unsigned long pfn, pgprot_t prot)
{
	pte_t pte = pfn_pte(pfn, prot);

	if (!IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL))
		return;

632
	pr_debug("Validating PTE special\n");
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	WARN_ON(!pte_special(pte_mkspecial(pte)));
}

static void __init pte_protnone_tests(unsigned long pfn, pgprot_t prot)
{
	pte_t pte = pfn_pte(pfn, prot);

	if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
		return;

643
	pr_debug("Validating PTE protnone\n");
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	WARN_ON(!pte_protnone(pte));
	WARN_ON(!pte_present(pte));
}

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static void __init pmd_protnone_tests(unsigned long pfn, pgprot_t prot)
{
	pmd_t pmd = pmd_mkhuge(pfn_pmd(pfn, prot));

	if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
		return;

656
	pr_debug("Validating PMD protnone\n");
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	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) { }
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

#ifdef CONFIG_ARCH_HAS_PTE_DEVMAP
static void __init pte_devmap_tests(unsigned long pfn, pgprot_t prot)
{
	pte_t pte = pfn_pte(pfn, prot);

669
	pr_debug("Validating PTE devmap\n");
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	WARN_ON(!pte_devmap(pte_mkdevmap(pte)));
}

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static void __init pmd_devmap_tests(unsigned long pfn, pgprot_t prot)
{
	pmd_t pmd = pfn_pmd(pfn, prot);

678
	pr_debug("Validating PMD devmap\n");
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	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)
{
	pud_t pud = pfn_pud(pfn, prot);

687
	pr_debug("Validating PUD devmap\n");
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	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) { }
#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) { }
#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) { }
#endif /* CONFIG_ARCH_HAS_PTE_DEVMAP */

static void __init pte_soft_dirty_tests(unsigned long pfn, pgprot_t prot)
{
	pte_t pte = pfn_pte(pfn, prot);

	if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY))
		return;

710
	pr_debug("Validating PTE soft dirty\n");
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	WARN_ON(!pte_soft_dirty(pte_mksoft_dirty(pte)));
	WARN_ON(pte_soft_dirty(pte_clear_soft_dirty(pte)));
}

static void __init pte_swap_soft_dirty_tests(unsigned long pfn, pgprot_t prot)
{
	pte_t pte = pfn_pte(pfn, prot);

	if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY))
		return;

722
	pr_debug("Validating PTE swap soft dirty\n");
723 724 725 726 727 728 729 730 731 732 733 734
	WARN_ON(!pte_swp_soft_dirty(pte_swp_mksoft_dirty(pte)));
	WARN_ON(pte_swp_soft_dirty(pte_swp_clear_soft_dirty(pte)));
}

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static void __init pmd_soft_dirty_tests(unsigned long pfn, pgprot_t prot)
{
	pmd_t pmd = pfn_pmd(pfn, prot);

	if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY))
		return;

735
	pr_debug("Validating PMD soft dirty\n");
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	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)
{
	pmd_t pmd = pfn_pmd(pfn, prot);

	if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY) ||
		!IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION))
		return;

748
	pr_debug("Validating PMD swap soft dirty\n");
749 750 751 752 753 754 755 756 757 758 759 760 761 762 763
	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_ARCH_HAS_PTE_DEVMAP */
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)
{
}
#endif /* CONFIG_ARCH_HAS_PTE_DEVMAP */

static void __init pte_swap_tests(unsigned long pfn, pgprot_t prot)
{
	swp_entry_t swp;
	pte_t pte;

764
	pr_debug("Validating PTE swap\n");
765 766 767 768 769 770 771 772 773 774 775 776
	pte = pfn_pte(pfn, prot);
	swp = __pte_to_swp_entry(pte);
	pte = __swp_entry_to_pte(swp);
	WARN_ON(pfn != pte_pfn(pte));
}

#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
static void __init pmd_swap_tests(unsigned long pfn, pgprot_t prot)
{
	swp_entry_t swp;
	pmd_t pmd;

777
	pr_debug("Validating PMD swap\n");
778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793
	pmd = pfn_pmd(pfn, prot);
	swp = __pmd_to_swp_entry(pmd);
	pmd = __swp_entry_to_pmd(swp);
	WARN_ON(pfn != pmd_pfn(pmd));
}
#else  /* !CONFIG_ARCH_ENABLE_THP_MIGRATION */
static void __init pmd_swap_tests(unsigned long pfn, pgprot_t prot) { }
#endif /* CONFIG_ARCH_ENABLE_THP_MIGRATION */

static void __init swap_migration_tests(void)
{
	struct page *page;
	swp_entry_t swp;

	if (!IS_ENABLED(CONFIG_MIGRATION))
		return;
794 795

	pr_debug("Validating swap migration\n");
796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834
	/*
	 * 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.
	 */
	page = alloc_page(GFP_KERNEL);
	if (!page) {
		pr_err("page allocation failed\n");
		return;
	}

	/*
	 * make_migration_entry() expects given page to be
	 * locked, otherwise it stumbles upon a BUG_ON().
	 */
	__SetPageLocked(page);
	swp = make_migration_entry(page, 1);
	WARN_ON(!is_migration_entry(swp));
	WARN_ON(!is_write_migration_entry(swp));

	make_migration_entry_read(&swp);
	WARN_ON(!is_migration_entry(swp));
	WARN_ON(is_write_migration_entry(swp));

	swp = make_migration_entry(page, 0);
	WARN_ON(!is_migration_entry(swp));
	WARN_ON(is_write_migration_entry(swp));
	__ClearPageLocked(page);
	__free_page(page);
}

#ifdef CONFIG_HUGETLB_PAGE
static void __init hugetlb_basic_tests(unsigned long pfn, pgprot_t prot)
{
	struct page *page;
	pte_t pte;

835
	pr_debug("Validating HugeTLB basic\n");
836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864
	/*
	 * 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);

	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);

	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) { }
#endif /* CONFIG_HUGETLB_PAGE */

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static void __init pmd_thp_tests(unsigned long pfn, pgprot_t prot)
{
	pmd_t pmd;

	if (!has_transparent_hugepage())
		return;

865
	pr_debug("Validating PMD based THP\n");
866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893
	/*
	 * pmd_trans_huge() and pmd_present() must return positive after
	 * MMU invalidation with pmd_mkinvalid(). This behavior is an
	 * optimization for transparent huge page. pmd_trans_huge() must
	 * be true if pmd_page() returns a valid THP to avoid taking the
	 * pmd_lock when others walk over non transhuge pmds (i.e. there
	 * are no THP allocated). Especially when splitting a THP and
	 * removing the present bit from the pmd, pmd_trans_huge() still
	 * needs to return true. pmd_present() should be true whenever
	 * pmd_trans_huge() returns true.
	 */
	pmd = pfn_pmd(pfn, prot);
	WARN_ON(!pmd_trans_huge(pmd_mkhuge(pmd)));

#ifndef __HAVE_ARCH_PMDP_INVALIDATE
	WARN_ON(!pmd_trans_huge(pmd_mkinvalid(pmd_mkhuge(pmd))));
	WARN_ON(!pmd_present(pmd_mkinvalid(pmd_mkhuge(pmd))));
#endif /* __HAVE_ARCH_PMDP_INVALIDATE */
}

#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
static void __init pud_thp_tests(unsigned long pfn, pgprot_t prot)
{
	pud_t pud;

	if (!has_transparent_hugepage())
		return;

894
	pr_debug("Validating PUD based THP\n");
895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913
	pud = pfn_pud(pfn, prot);
	WARN_ON(!pud_trans_huge(pud_mkhuge(pud)));

	/*
	 * pud_mkinvalid() has been dropped for now. Enable back
	 * these tests when it comes back with a modified pud_present().
	 *
	 * WARN_ON(!pud_trans_huge(pud_mkinvalid(pud_mkhuge(pud))));
	 * WARN_ON(!pud_present(pud_mkinvalid(pud_mkhuge(pud))));
	 */
}
#else  /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
static void __init pud_thp_tests(unsigned long pfn, pgprot_t prot) { }
#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) { }
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

914 915 916 917 918 919 920 921 922 923 924 925 926 927
static unsigned long __init get_random_vaddr(void)
{
	unsigned long random_vaddr, random_pages, total_user_pages;

	total_user_pages = (TASK_SIZE - FIRST_USER_ADDRESS) / PAGE_SIZE;

	random_pages = get_random_long() % total_user_pages;
	random_vaddr = FIRST_USER_ADDRESS + random_pages * PAGE_SIZE;

	return random_vaddr;
}

static int __init debug_vm_pgtable(void)
{
928
	struct vm_area_struct *vma;
929 930 931 932 933 934 935
	struct mm_struct *mm;
	pgd_t *pgdp;
	p4d_t *p4dp, *saved_p4dp;
	pud_t *pudp, *saved_pudp;
	pmd_t *pmdp, *saved_pmdp, pmd;
	pte_t *ptep;
	pgtable_t saved_ptep;
936
	pgprot_t prot, protnone;
937 938 939
	phys_addr_t paddr;
	unsigned long vaddr, pte_aligned, pmd_aligned;
	unsigned long pud_aligned, p4d_aligned, pgd_aligned;
940
	spinlock_t *ptl = NULL;
941 942 943 944 945 946 947 948 949 950

	pr_info("Validating architecture page table helpers\n");
	prot = vm_get_page_prot(VMFLAGS);
	vaddr = get_random_vaddr();
	mm = mm_alloc();
	if (!mm) {
		pr_err("mm_struct allocation failed\n");
		return 1;
	}

951 952 953 954 955 956
	/*
	 * __P000 (or even __S000) will help create page table entries with
	 * PROT_NONE permission as required for pxx_protnone_tests().
	 */
	protnone = __P000;

957 958 959 960 961 962
	vma = vm_area_alloc(mm);
	if (!vma) {
		pr_err("vma allocation failed\n");
		return 1;
	}

963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984
	/*
	 * 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);

	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);
	p4dp = p4d_alloc(mm, pgdp, vaddr);
	pudp = pud_alloc(mm, p4dp, vaddr);
	pmdp = pmd_alloc(mm, pudp, vaddr);
985 986 987 988 989 990 991
	/*
	 * Allocate pgtable_t
	 */
	if (pte_alloc(mm, pmdp)) {
		pr_err("pgtable allocation failed\n");
		return 1;
	}
992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010

	/*
	 * 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_p4dp = p4d_offset(pgdp, 0UL);
	saved_pudp = pud_offset(p4dp, 0UL);
	saved_pmdp = pmd_offset(pudp, 0UL);
	saved_ptep = pmd_pgtable(pmd);

	pte_basic_tests(pte_aligned, prot);
	pmd_basic_tests(pmd_aligned, prot);
	pud_basic_tests(pud_aligned, prot);
	p4d_basic_tests(p4d_aligned, prot);
	pgd_basic_tests(pgd_aligned, prot);

1011 1012 1013
	pmd_leaf_tests(pmd_aligned, prot);
	pud_leaf_tests(pud_aligned, prot);

1014 1015
	pte_savedwrite_tests(pte_aligned, protnone);
	pmd_savedwrite_tests(pmd_aligned, protnone);
1016

1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037
	pte_special_tests(pte_aligned, prot);
	pte_protnone_tests(pte_aligned, protnone);
	pmd_protnone_tests(pmd_aligned, protnone);

	pte_devmap_tests(pte_aligned, prot);
	pmd_devmap_tests(pmd_aligned, prot);
	pud_devmap_tests(pud_aligned, prot);

	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_swap_tests(pte_aligned, prot);
	pmd_swap_tests(pmd_aligned, prot);

	swap_migration_tests();

	pmd_thp_tests(pmd_aligned, prot);
	pud_thp_tests(pud_aligned, prot);

1038 1039
	hugetlb_basic_tests(pte_aligned, prot);

1040 1041 1042 1043
	/*
	 * Page table modifying tests. They need to hold
	 * proper page table lock.
	 */
1044

1045
	ptep = pte_offset_map_lock(mm, pmdp, vaddr, &ptl);
1046
	pte_clear_tests(mm, ptep, pte_aligned, vaddr, prot);
1047
	pte_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
1048
	pte_unmap_unlock(ptep, ptl);
1049

1050 1051
	ptl = pmd_lock(mm, pmdp);
	pmd_clear_tests(mm, pmdp);
1052
	pmd_advanced_tests(mm, vma, pmdp, pmd_aligned, vaddr, prot, saved_ptep);
1053
	pmd_huge_tests(pmdp, pmd_aligned, prot);
1054 1055 1056 1057 1058 1059
	pmd_populate_tests(mm, pmdp, saved_ptep);
	spin_unlock(ptl);

	ptl = pud_lock(mm, pudp);
	pud_clear_tests(mm, pudp);
	pud_advanced_tests(mm, vma, pudp, pud_aligned, vaddr, prot);
1060
	pud_huge_tests(pudp, pud_aligned, prot);
1061 1062
	pud_populate_tests(mm, pudp, saved_pmdp);
	spin_unlock(ptl);
1063

1064 1065 1066
	spin_lock(&mm->page_table_lock);
	p4d_clear_tests(mm, p4dp);
	pgd_clear_tests(mm, pgdp);
1067 1068
	p4d_populate_tests(mm, p4dp, saved_pudp);
	pgd_populate_tests(mm, pgdp, saved_p4dp);
1069
	spin_unlock(&mm->page_table_lock);
1070

1071 1072 1073 1074 1075
	p4d_free(mm, saved_p4dp);
	pud_free(mm, saved_pudp);
	pmd_free(mm, saved_pmdp);
	pte_free(mm, saved_ptep);

1076
	vm_area_free(vma);
1077 1078 1079 1080 1081 1082 1083
	mm_dec_nr_puds(mm);
	mm_dec_nr_pmds(mm);
	mm_dec_nr_ptes(mm);
	mmdrop(mm);
	return 0;
}
late_initcall(debug_vm_pgtable);