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mm/debug_vm_pgtable: ensure THP availability via has_transparent_huge…
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[ Upstream commit 65ac1a6 ]

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: 787d563 ("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>
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@gregkh
Anshuman Khandual authored and gregkh committed Jul 14, 2021
1 parent a537268 commit 9b0add9
Showing 1 changed file with 51 additions and 12 deletions.
63 changes: 51 additions & 12 deletions mm/debug_vm_pgtable.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -146,13 +146,14 @@ static void __init pte_savedwrite_tests(unsigned long pfn, pgprot_t prot)
static void __init pmd_basic_tests(unsigned long pfn, int idx)
{
pgprot_t prot = protection_map[idx];
pmd_t pmd = pfn_pmd(pfn, prot);
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
Expand Down Expand Up @@ -185,7 +186,7 @@ static void __init pmd_advanced_tests(struct mm_struct *mm,
unsigned long pfn, unsigned long vaddr,
pgprot_t prot, pgtable_t pgtable)
{
pmd_t pmd = pfn_pmd(pfn, prot);
pmd_t pmd;

if (!has_transparent_hugepage())
return;
Expand Down Expand Up @@ -232,9 +233,14 @@ static void __init pmd_advanced_tests(struct mm_struct *mm,

static void __init pmd_leaf_tests(unsigned long pfn, pgprot_t prot)
{
pmd_t pmd = pfn_pmd(pfn, 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.
*/
Expand Down Expand Up @@ -267,12 +273,16 @@ static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot)

static void __init pmd_savedwrite_tests(unsigned long pfn, pgprot_t prot)
{
pmd_t pmd = pfn_pmd(pfn, 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))));
}
Expand All @@ -281,13 +291,14 @@ static void __init pmd_savedwrite_tests(unsigned long pfn, pgprot_t prot)
static void __init pud_basic_tests(struct mm_struct *mm, unsigned long pfn, int idx)
{
pgprot_t prot = protection_map[idx];
pud_t pud = pfn_pud(pfn, prot);
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
Expand Down Expand Up @@ -323,7 +334,7 @@ static void __init pud_advanced_tests(struct mm_struct *mm,
unsigned long pfn, unsigned long vaddr,
pgprot_t prot)
{
pud_t pud = pfn_pud(pfn, prot);
pud_t pud;

if (!has_transparent_hugepage())
return;
Expand All @@ -332,6 +343,7 @@ static void __init pud_advanced_tests(struct mm_struct *mm,
/* 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);
Expand Down Expand Up @@ -370,9 +382,13 @@ static void __init pud_advanced_tests(struct mm_struct *mm,

static void __init pud_leaf_tests(unsigned long pfn, pgprot_t prot)
{
pud_t pud = pfn_pud(pfn, 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.
*/
Expand Down Expand Up @@ -654,12 +670,16 @@ 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)
{
pmd_t pmd = pmd_mkhuge(pfn_pmd(pfn, 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));
}
Expand All @@ -679,18 +699,26 @@ static void __init pte_devmap_tests(unsigned long pfn, pgprot_t prot)
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static void __init pmd_devmap_tests(unsigned long pfn, pgprot_t prot)
{
pmd_t pmd = pfn_pmd(pfn, 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 = pfn_pud(pfn, 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 */
Expand Down Expand Up @@ -733,25 +761,33 @@ 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)
{
pmd_t pmd = pfn_pmd(pfn, 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 = pfn_pmd(pfn, 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)));
}
Expand Down Expand Up @@ -780,6 +816,9 @@ 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);
Expand Down

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