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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>,
	linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org,
	linux-snps-arc@lists.infradead.org, x86@kernel.org,
	linux-arch@vger.kernel.org,
	Gerald Schaefer <gerald.schaefer@de.ibm.com>,
	Christophe Leroy <christophe.leroy@c-s.fr>,
	Vineet Gupta <vgupta@synopsys.com>,
	Mike Rapoport <rppt@linux.ibm.com>, Qian Cai <cai@lca.pw>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Subject: [PATCH v3 01/13] powerpc/mm: Add DEBUG_VM WARN for pmd_clear
Date: Thu, 27 Aug 2020 13:34:26 +0530	[thread overview]
Message-ID: <20200827080438.315345-2-aneesh.kumar@linux.ibm.com> (raw)
In-Reply-To: <20200827080438.315345-1-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:[~2020-08-27  8:05 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-27  8:04 [PATCH v3 00/13] mm/debug_vm_pgtable fixes Aneesh Kumar K.V
2020-08-27  8:04 ` Aneesh Kumar K.V [this message]
2020-09-01  3:12   ` [PATCH v3 01/13] powerpc/mm: Add DEBUG_VM WARN for pmd_clear Anshuman Khandual
2020-08-27  8:04 ` [PATCH v3 02/13] powerpc/mm: Move setting pte specific flags to pfn_pte Aneesh Kumar K.V
2020-09-01  3:13   ` Anshuman Khandual
2020-08-27  8:04 ` [PATCH v3 03/13] mm/debug_vm_pgtable/ppc64: Avoid setting top bits in radom value Aneesh Kumar K.V
2020-09-01  3:15   ` Anshuman Khandual
2020-09-01  6:21     ` Aneesh Kumar K.V
2020-09-01  7:32       ` Anshuman Khandual
2020-09-01  7:36         ` Aneesh Kumar K.V
2020-09-01  7:46           ` Anshuman Khandual
2020-09-01  7:55             ` Aneesh Kumar K.V
2020-09-02  3:45               ` Anshuman Khandual
2020-08-27  8:04 ` [PATCH v3 04/13] mm/debug_vm_pgtables/hugevmap: Use the arch helper to identify huge vmap support Aneesh Kumar K.V
2020-09-01  3:16   ` Anshuman Khandual
2020-08-27  8:04 ` [PATCH v3 05/13] mm/debug_vm_pgtable/savedwrite: Enable savedwrite test with CONFIG_NUMA_BALANCING Aneesh Kumar K.V
2020-09-01  3:18   ` Anshuman Khandual
2020-08-27  8:04 ` [PATCH v3 06/13] mm/debug_vm_pgtable/THP: Mark the pte entry huge before using set_pmd/pud_at Aneesh Kumar K.V
2020-09-01  3:21   ` Anshuman Khandual
2020-09-01  6:23     ` Aneesh Kumar K.V
2020-08-27  8:04 ` [PATCH v3 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
2020-08-27  8:04 ` [PATCH v3 08/13] mm/debug_vm_pgtable/thp: Use page table depost/withdraw with THP Aneesh Kumar K.V
2020-09-01  3:22   ` Anshuman Khandual
2020-09-01  6:25     ` Aneesh Kumar K.V
2020-09-01  6:50       ` Christophe Leroy
2020-09-01  7:40         ` Aneesh Kumar K.V
2020-09-01  7:51           ` Christophe Leroy
2020-09-02  3:45             ` Anshuman Khandual
2020-08-27  8:04 ` [PATCH v3 09/13] mm/debug_vm_pgtable/locks: Move non page table modifying test together Aneesh Kumar K.V
2020-09-01  3:41   ` Anshuman Khandual
2020-09-01  6:38     ` Aneesh Kumar K.V
2020-09-01  9:33       ` Anshuman Khandual
2020-09-01  9:36         ` Aneesh Kumar K.V
2020-09-01  9:58           ` Anshuman Khandual
2020-08-27  8:04 ` [PATCH v3 10/13] mm/debug_vm_pgtable/locks: Take correct page table lock Aneesh Kumar K.V
2020-09-01  3:44   ` Anshuman Khandual
2020-08-27  8:04 ` [PATCH v3 11/13] mm/debug_vm_pgtable/pmd_clear: Don't use pmd/pud_clear on pte entries Aneesh Kumar K.V
2020-08-27  8:04 ` [PATCH v3 12/13] mm/debug_vm_pgtable/hugetlb: Disable hugetlb test on ppc64 Aneesh Kumar K.V
2020-09-01  4:03   ` Anshuman Khandual
2020-09-01  6:30     ` Aneesh Kumar K.V
2020-09-01  7:59       ` Christophe Leroy
2020-09-02 13:05       ` Anshuman Khandual
2020-09-02 13:20         ` Aneesh Kumar K.V
2020-08-27  8:04 ` [PATCH v3 13/13] mm/debug_vm_pgtable: populate a pte entry before fetching it Aneesh Kumar K.V
2020-08-27 12:17   ` kernel test robot
2020-09-01  3:25   ` Anshuman Khandual
2020-09-01  6:37     ` Aneesh Kumar K.V
2020-09-01  7:38       ` Anshuman Khandual
2020-09-01  9:58         ` Aneesh Kumar K.V
2020-09-02  3:49           ` Anshuman Khandual
2020-09-02  3:58             ` Aneesh Kumar K.V

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