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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: linux-mm@kvack.org, akpm@linux-foundation.org
Cc: mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Subject: [PATCH v2 01/13] powerpc/mm: Add DEBUG_VM WARN for pmd_clear
Date: Wed, 19 Aug 2020 18:30:55 +0530	[thread overview]
Message-ID: <20200819130107.478414-2-aneesh.kumar@linux.ibm.com> (raw)
In-Reply-To: <20200819130107.478414-1-aneesh.kumar@linux.ibm.com>

With the hash page table, the kernel should not use pmd_clear for clearing
huge pte entries. Add a DEBUG_VM WARN to catch the wrong usage.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
 arch/powerpc/include/asm/book3s/64/pgtable.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 6de56c3b33c4..079211968987 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -868,6 +868,13 @@ static inline bool pte_ci(pte_t pte)
 
 static inline void pmd_clear(pmd_t *pmdp)
 {
+	if (IS_ENABLED(CONFIG_DEBUG_VM) && !radix_enabled()) {
+		/*
+		 * Don't use this if we can possibly have a hash page table
+		 * entry mapping this.
+		 */
+		WARN_ON((pmd_val(*pmdp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE));
+	}
 	*pmdp = __pmd(0);
 }
 
@@ -916,6 +923,13 @@ static inline int pmd_bad(pmd_t pmd)
 
 static inline void pud_clear(pud_t *pudp)
 {
+	if (IS_ENABLED(CONFIG_DEBUG_VM) && !radix_enabled()) {
+		/*
+		 * Don't use this if we can possibly have a hash page table
+		 * entry mapping this.
+		 */
+		WARN_ON((pud_val(*pudp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE));
+	}
 	*pudp = __pud(0);
 }
 
-- 
2.26.2



WARNING: multiple messages have this Message-ID (diff)
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: linux-mm@kvack.org, akpm@linux-foundation.org
Cc: linuxppc-dev@lists.ozlabs.org,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
	Anshuman Khandual <anshuman.khandual@arm.com>
Subject: [PATCH v2 01/13] powerpc/mm: Add DEBUG_VM WARN for pmd_clear
Date: Wed, 19 Aug 2020 18:30:55 +0530	[thread overview]
Message-ID: <20200819130107.478414-2-aneesh.kumar@linux.ibm.com> (raw)
In-Reply-To: <20200819130107.478414-1-aneesh.kumar@linux.ibm.com>

With the hash page table, the kernel should not use pmd_clear for clearing
huge pte entries. Add a DEBUG_VM WARN to catch the wrong usage.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
 arch/powerpc/include/asm/book3s/64/pgtable.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 6de56c3b33c4..079211968987 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -868,6 +868,13 @@ static inline bool pte_ci(pte_t pte)
 
 static inline void pmd_clear(pmd_t *pmdp)
 {
+	if (IS_ENABLED(CONFIG_DEBUG_VM) && !radix_enabled()) {
+		/*
+		 * Don't use this if we can possibly have a hash page table
+		 * entry mapping this.
+		 */
+		WARN_ON((pmd_val(*pmdp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE));
+	}
 	*pmdp = __pmd(0);
 }
 
@@ -916,6 +923,13 @@ static inline int pmd_bad(pmd_t pmd)
 
 static inline void pud_clear(pud_t *pudp)
 {
+	if (IS_ENABLED(CONFIG_DEBUG_VM) && !radix_enabled()) {
+		/*
+		 * Don't use this if we can possibly have a hash page table
+		 * entry mapping this.
+		 */
+		WARN_ON((pud_val(*pudp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE));
+	}
 	*pudp = __pud(0);
 }
 
-- 
2.26.2


  reply	other threads:[~2020-08-19 13:02 UTC|newest]

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-19 13:00 [PATCH v2 00/13] mm/debug_vm_pgtable fixes Aneesh Kumar K.V
2020-08-19 13:00 ` Aneesh Kumar K.V
2020-08-19 13:00 ` Aneesh Kumar K.V [this message]
2020-08-19 13:00   ` [PATCH v2 01/13] powerpc/mm: Add DEBUG_VM WARN for pmd_clear Aneesh Kumar K.V
2020-08-19 13:00 ` [PATCH v2 02/13] powerpc/mm: Move setting pte specific flags to pfn_pte Aneesh Kumar K.V
2020-08-19 13:00   ` Aneesh Kumar K.V
2020-08-19 13:00 ` [PATCH v2 03/13] mm/debug_vm_pgtable/ppc64: Avoid setting top bits in radom value Aneesh Kumar K.V
2020-08-19 13:00   ` Aneesh Kumar K.V
2020-08-19 13:00 ` [PATCH v2 04/13] mm/debug_vm_pgtables/hugevmap: Use the arch helper to identify huge vmap support Aneesh Kumar K.V
2020-08-19 13:00   ` Aneesh Kumar K.V
2020-08-19 16:29   ` kernel test robot
2020-08-19 16:29     ` kernel test robot
2020-08-19 16:29     ` kernel test robot
2020-08-20  5:31     ` Aneesh Kumar K.V
2020-08-20  5:31       ` Aneesh Kumar K.V
2020-08-21  8:38   ` Anshuman Khandual
2020-08-21  8:38     ` Anshuman Khandual
2020-08-19 13:00 ` [PATCH v2 05/13] mm/debug_vm_pgtable/savedwrite: Enable savedwrite test with CONFIG_NUMA_BALANCING Aneesh Kumar K.V
2020-08-19 13:00   ` Aneesh Kumar K.V
2020-08-19 13:01 ` [PATCH v2 06/13] mm/debug_vm_pgtable/THP: Mark the pte entry huge before using set_pmd/pud_at Aneesh Kumar K.V
2020-08-19 13:01   ` Aneesh Kumar K.V
2020-08-19 13:01 ` [PATCH v2 07/13] mm/debug_vm_pgtable/set_pte/pmd/pud: Don't use set_*_at to update an existing pte entry Aneesh Kumar K.V
2020-08-19 13:01   ` Aneesh Kumar K.V
2020-08-20 14:32   ` Christophe Leroy
2020-08-21  7:14     ` Aneesh Kumar K.V
2020-08-21  8:20       ` Anshuman Khandual
2020-08-19 13:01 ` [PATCH v2 08/13] mm/debug_vm_pgtable/thp: Use page table depost/withdraw with THP Aneesh Kumar K.V
2020-08-19 13:01   ` Aneesh Kumar K.V
2020-08-19 13:01 ` [PATCH v2 09/13] mm/debug_vm_pgtable/locks: Move non page table modifying test together Aneesh Kumar K.V
2020-08-19 13:01   ` Aneesh Kumar K.V
2020-08-19 13:01 ` [PATCH v2 10/13] mm/debug_vm_pgtable/locks: Take correct page table lock Aneesh Kumar K.V
2020-08-19 13:01   ` Aneesh Kumar K.V
2020-08-21  8:03   ` Anshuman Khandual
2020-08-21  8:03     ` Anshuman Khandual
2020-08-21  8:08     ` Aneesh Kumar K.V
2020-08-21  8:08       ` Aneesh Kumar K.V
2020-08-19 13:01 ` [PATCH v2 11/13] mm/debug_vm_pgtable/pmd_clear: Don't use pmd/pud_clear on pte entries Aneesh Kumar K.V
2020-08-19 13:01   ` Aneesh Kumar K.V
2020-08-19 13:01 ` [PATCH v2 12/13] mm/debug_vm_pgtable/hugetlb: Disable hugetlb test on ppc64 Aneesh Kumar K.V
2020-08-19 13:01   ` Aneesh Kumar K.V
2020-08-19 13:01 ` [PATCH v2 13/13] mm/debug_vm_pgtable: populate a pte entry before fetching it Aneesh Kumar K.V
2020-08-19 13:01   ` Aneesh Kumar K.V
2020-08-19 13:45 ` [PATCH v2 00/13] mm/debug_vm_pgtable fixes Aneesh Kumar K.V
2020-08-19 13:45   ` Aneesh Kumar K.V
2020-08-21  3:33   ` Anshuman Khandual
2020-08-21  3:33     ` Anshuman Khandual
2020-08-21  4:20     ` Anshuman Khandual
2020-08-21  4:20       ` Anshuman Khandual
2020-08-21  6:53     ` Aneesh Kumar K.V
2020-08-21  6:53       ` Aneesh Kumar K.V
2020-08-21  8:01       ` Anshuman Khandual
2020-08-21  8:01         ` Anshuman Khandual
2020-08-21  8:10         ` Aneesh Kumar K.V
2020-08-21  8:10           ` Aneesh Kumar K.V
2020-08-21  8:50           ` Aneesh Kumar K.V
2020-08-21  8:50             ` Aneesh Kumar K.V
2020-08-21  9:09             ` Anshuman Khandual
2020-08-21  9:09               ` Anshuman Khandual
2020-08-21  8:51 ` Anshuman Khandual
2020-08-21  8:51   ` Anshuman Khandual
2020-08-21  8:51   ` Anshuman Khandual
2020-08-21  8:51   ` Anshuman Khandual
2020-08-21  8:51   ` Anshuman Khandual
2020-09-01  8:03   ` Christophe Leroy
2020-09-01  8:03     ` Christophe Leroy
2020-09-01  8:03     ` Christophe Leroy
2020-09-01  8:03     ` Christophe Leroy
2020-09-01  8:03     ` Christophe Leroy
2020-09-01  9:11     ` Anshuman Khandual
2020-09-01  9:11       ` Anshuman Khandual
2020-09-01  9:11       ` Anshuman Khandual
2020-09-01  9:11       ` Anshuman Khandual
2020-09-01  9:11       ` Anshuman Khandual

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