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epyc7002
linux_dsm_epyc7002/mm/debug_vm_pgtable.c
Anshuman Khandual 29ae2c9c9c mm/debug_vm_pgtable: ensure THP availability via has_transparent_hugepage() 
[ Upstream commit 65ac1a60a57e2c55f2ac37f27095f6b012295e81 ]

On certain platforms, THP support could not just be validated via the
build option CONFIG_TRANSPARENT_HUGEPAGE.  Instead
has_transparent_hugepage() also needs to be called upon to verify THP
runtime support.  Otherwise the debug test will just run into unusable THP
helpers like in the case of a 4K hash config on powerpc platform [1].
This just moves all pfn_pmd() and pfn_pud() after THP runtime validation
with has_transparent_hugepage() which prevents the mentioned problem.

[1] https://bugzilla.kernel.org/show_bug.cgi?id=213069

Link: https://lkml.kernel.org/r/1621397588-19211-1-git-send-email-anshuman.khandual@arm.com
Fixes: 787d563b86 ("mm/debug_vm_pgtable: fix kernel crash by checking for THP support")
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14 16:56:13 +02:00

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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>
*/
#define pr_fmt(fmt) "debug_vm_pgtable: [%-25s]: " fmt, __func__
#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>
#include <linux/pgtable.h>
#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>
#include <linux/io.h>
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
/*
* 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.
*/
#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
* have affect any other platform. Also avoid the 62nd bit on ppc64 that is
* used to mark a pte entry.
*/
#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)
#define RANDOM_NZVALUE GENMASK(7, 0)
static void __init pte_basic_tests(unsigned long pfn, int idx)
{
pgprot_t prot = protection_map[idx];
pte_t pte = pfn_pte(pfn, prot);
unsigned long val = idx, *ptr = &val;
pr_debug("Validating PTE basic (%pGv)\n", ptr);
/*
* 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)));
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))));
WARN_ON(pte_dirty(pte_wrprotect(pte_mkclean(pte))));
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)
{
pte_t pte = pfn_pte(pfn, prot);
/*
* Architectures optimize set_pte_at by avoiding TLB flush.
* This requires set_pte_at to be not used to update an
* existing pte entry. Clear pte before we do set_pte_at
*/
pr_debug("Validating PTE advanced\n");
pte = pfn_pte(pfn, prot);
set_pte_at(mm, vaddr, ptep, pte);
ptep_set_wrprotect(mm, vaddr, ptep);
pte = ptep_get(ptep);
WARN_ON(pte_write(pte));
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));
pte = pfn_pte(pfn, prot);
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);
if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
return;
pr_debug("Validating PTE saved write\n");
WARN_ON(!pte_savedwrite(pte_mk_savedwrite(pte_clear_savedwrite(pte))));
WARN_ON(pte_savedwrite(pte_clear_savedwrite(pte_mk_savedwrite(pte))));
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static void __init pmd_basic_tests(unsigned long pfn, int idx)
{
pgprot_t prot = protection_map[idx];
unsigned long val = idx, *ptr = &val;
pmd_t pmd;
if (!has_transparent_hugepage())
return;
pr_debug("Validating PMD basic (%pGv)\n", ptr);
pmd = pfn_pmd(pfn, prot);
/*
* 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)));
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))));
WARN_ON(pmd_dirty(pmd_wrprotect(pmd_mkclean(pmd))));
WARN_ON(!pmd_dirty(pmd_wrprotect(pmd_mkdirty(pmd))));
/*
* 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)));
}
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)
{
pmd_t pmd;
if (!has_transparent_hugepage())
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);
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));
pmd = pmd_mkhuge(pfn_pmd(pfn, prot));
pmd = pmd_mkyoung(pmd);
set_pmd_at(mm, vaddr, pmdp, pmd);
pmdp_test_and_clear_young(vma, vaddr, pmdp);
pmd = READ_ONCE(*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);
}
static void __init pmd_leaf_tests(unsigned long pfn, pgprot_t prot)
{
pmd_t pmd;
if (!has_transparent_hugepage())
return;
pr_debug("Validating PMD leaf\n");
pmd = pfn_pmd(pfn, prot);
/*
* PMD based THP is a leaf entry.
*/
pmd = pmd_mkhuge(pmd);
WARN_ON(!pmd_leaf(pmd));
}
#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot)
{
pmd_t pmd;
if (!arch_ioremap_pmd_supported())
return;
pr_debug("Validating PMD huge\n");
/*
* 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));
}
#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 */
static void __init pmd_savedwrite_tests(unsigned long pfn, pgprot_t prot)
{
pmd_t pmd;
if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
return;
if (!has_transparent_hugepage())
return;
pr_debug("Validating PMD saved write\n");
pmd = pfn_pmd(pfn, prot);
WARN_ON(!pmd_savedwrite(pmd_mk_savedwrite(pmd_clear_savedwrite(pmd))));
WARN_ON(pmd_savedwrite(pmd_clear_savedwrite(pmd_mk_savedwrite(pmd))));
}
#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
static void __init pud_basic_tests(struct mm_struct *mm, unsigned long pfn, int idx)
{
pgprot_t prot = protection_map[idx];
unsigned long val = idx, *ptr = &val;
pud_t pud;
if (!has_transparent_hugepage())
return;
pr_debug("Validating PUD basic (%pGv)\n", ptr);
pud = pfn_pud(pfn, prot);
/*
* 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)));
WARN_ON(!pud_same(pud, pud));
WARN_ON(!pud_young(pud_mkyoung(pud_mkold(pud))));
WARN_ON(!pud_dirty(pud_mkdirty(pud_mkclean(pud))));
WARN_ON(pud_dirty(pud_mkclean(pud_mkdirty(pud))));
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))));
WARN_ON(pud_dirty(pud_wrprotect(pud_mkclean(pud))));
WARN_ON(!pud_dirty(pud_wrprotect(pud_mkdirty(pud))));
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)));
}
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;
if (!has_transparent_hugepage())
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);
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)));
#ifndef __PAGETABLE_PMD_FOLDED
pudp_huge_get_and_clear_full(mm, vaddr, pudp, 1);
pud = READ_ONCE(*pudp);
WARN_ON(!pud_none(pud));
#endif /* __PAGETABLE_PMD_FOLDED */
pud = pfn_pud(pfn, prot);
pud = pud_mkyoung(pud);
set_pud_at(mm, vaddr, pudp, pud);
pudp_test_and_clear_young(vma, vaddr, pudp);
pud = READ_ONCE(*pudp);
WARN_ON(pud_young(pud));
pudp_huge_get_and_clear(mm, vaddr, pudp);
}
static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot)
{
pud_t pud;
if (!has_transparent_hugepage())
return;
pr_debug("Validating PUD leaf\n");
pud = pfn_pud(pfn, prot);
/*
* PUD based THP is a leaf entry.
*/
pud = pud_mkhuge(pud);
WARN_ON(!pud_leaf(pud));
}
#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
{
pud_t pud;
if (!arch_ioremap_pud_supported())
return;
pr_debug("Validating PUD huge\n");
/*
* X86 defined pud_set_huge() verifies that the given
* PUD is not a populated non-leaf entry.
*/
WRITE_ONCE(*pudp, __pud(0));
WARN_ON(!pud_set_huge(pudp, __pfn_to_phys(pfn), prot));
WARN_ON(!pud_clear_huge(pudp));
pud = READ_ONCE(*pudp);
WARN_ON(!pud_none(pud));
}
#else /* !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 */
#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_advanced_tests(struct mm_struct *mm,
struct vm_area_struct *vma, pud_t *pudp,
unsigned long pfn, unsigned long vaddr,
pgprot_t prot)
{
}
static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot) { }
static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
{
}
#endif /* 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_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 pud_advanced_tests(struct mm_struct *mm,
struct vm_area_struct *vma, pud_t *pudp,
unsigned long pfn, unsigned long vaddr,
pgprot_t prot)
{
}
static void __init pmd_leaf_tests(unsigned long pfn, pgprot_t prot) { }
static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot) { }
static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot)
{
}
static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
{
}
static void __init pmd_savedwrite_tests(unsigned long pfn, pgprot_t prot) { }
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
static void __init p4d_basic_tests(unsigned long pfn, pgprot_t prot)
{
p4d_t p4d;
pr_debug("Validating P4D basic\n");
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;
pr_debug("Validating PGD basic\n");
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;
pr_debug("Validating PUD clear\n");
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;
pr_debug("Validating PUD populate\n");
/*
* 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;
pr_debug("Validating P4D clear\n");
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;
pr_debug("Validating P4D populate\n");
/*
* 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;
pr_debug("Validating PGD clear\n");
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;
pr_debug("Validating PGD populate\n");
/*
* 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,
unsigned long pfn, unsigned long vaddr,
pgprot_t prot)
{
pte_t pte = pfn_pte(pfn, prot);
pr_debug("Validating PTE clear\n");
#ifndef CONFIG_RISCV
pte = __pte(pte_val(pte) | RANDOM_ORVALUE);
#endif
set_pte_at(mm, vaddr, ptep, pte);
barrier();
pte_clear(mm, vaddr, ptep);
pte = ptep_get(ptep);
WARN_ON(!pte_none(pte));
}
static void __init pmd_clear_tests(struct mm_struct *mm, pmd_t *pmdp)
{
pmd_t pmd = READ_ONCE(*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);
WARN_ON(!pmd_none(pmd));
}
static void __init pmd_populate_tests(struct mm_struct *mm, pmd_t *pmdp,
pgtable_t pgtable)
{
pmd_t pmd;
pr_debug("Validating PMD populate\n");
/*
* 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));
}
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;
pr_debug("Validating PTE special\n");
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;
pr_debug("Validating PTE protnone\n");
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;
if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
return;
if (!has_transparent_hugepage())
return;
pr_debug("Validating PMD protnone\n");
pmd = pmd_mkhuge(pfn_pmd(pfn, prot));
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);
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)
{
pmd_t pmd;
if (!has_transparent_hugepage())
return;
pr_debug("Validating PMD devmap\n");
pmd = pfn_pmd(pfn, 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)
{
pud_t pud;
if (!has_transparent_hugepage())
return;
pr_debug("Validating PUD devmap\n");
pud = pfn_pud(pfn, 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) { }
#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;
pr_debug("Validating PTE soft dirty\n");
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;
pr_debug("Validating PTE swap soft dirty\n");
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;
if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY))
return;
if (!has_transparent_hugepage())
return;
pr_debug("Validating PMD soft dirty\n");
pmd = pfn_pmd(pfn, 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)
{
pmd_t pmd;
if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY) ||
!IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION))
return;
if (!has_transparent_hugepage())
return;
pr_debug("Validating PMD swap soft dirty\n");
pmd = pfn_pmd(pfn, 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_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;
pr_debug("Validating PTE swap\n");
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;
if (!has_transparent_hugepage())
return;
pr_debug("Validating PMD swap\n");
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;
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.
*/
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;
pr_debug("Validating HugeTLB basic\n");
/*
* 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;
pr_debug("Validating PMD based THP\n");
/*
* 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;
pr_debug("Validating PUD based THP\n");
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 */
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)
{
struct vm_area_struct *vma;
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;
pgprot_t prot, protnone;
phys_addr_t paddr;
unsigned long vaddr, pte_aligned, pmd_aligned;
unsigned long pud_aligned, p4d_aligned, pgd_aligned;
spinlock_t *ptl = NULL;
int idx;
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;
}
/*
* __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");
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);
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);
/*
* 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_p4dp = p4d_offset(pgdp, 0UL);
saved_pudp = pud_offset(p4dp, 0UL);
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
* true irrespective of the starting protection value for a
* 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);
}
/*
* Both P4D and PGD level tests are very basic which do not
* involve creating page table entries from the protection
* value and the given pfn. Hence just keep them out from
* the above iteration for now to save some test execution
* time.
*/
p4d_basic_tests(p4d_aligned, prot);
pgd_basic_tests(pgd_aligned, prot);
pmd_leaf_tests(pmd_aligned, prot);
pud_leaf_tests(pud_aligned, prot);
pte_savedwrite_tests(pte_aligned, protnone);
pmd_savedwrite_tests(pmd_aligned, protnone);
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);
hugetlb_basic_tests(pte_aligned, prot);
/*
* Page table modifying tests. They need to hold
* 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);
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);
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);
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);
p4d_free(mm, saved_p4dp);
pud_free(mm, saved_pudp);
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);
return 0;
}
late_initcall(debug_vm_pgtable);
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