Commit 65ac1a60 authored by Anshuman Khandual's avatar Anshuman Khandual Committed by Linus Torvalds
Browse files

mm/debug_vm_pgtable: ensure THP availability via has_transparent_hugepage() 

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: 787d563b ("mm/debug_vm_pgtable: fix kernel crash by checking for THP support")
Signed-off-by: default avatarAnshuman 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 85f29cd6

mm/debug_vm_pgtable.c

+51 −12
Original line number Diff line number Diff line
@@ -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
@@ -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;
@@ -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.

	 */
@@ -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))));

}
@@ -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
@@ -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;
@@ -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);
@@ -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.

	 */
@@ -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));

}
@@ -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 */
@@ -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)));

}
@@ -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);