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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 01/16] powerpc/mm: Add DEBUG_VM WARN for pmd_clear
Date: Wed, 12 Aug 2020 12:03:43 +0530	[thread overview]
Message-ID: <20200812063358.369514-1-aneesh.kumar@linux.ibm.com> (raw)

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:[~2020-08-12  6:36 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-12  6:33 Aneesh Kumar K.V [this message]
2020-08-12  6:33 ` [PATCH 02/16] debug_vm_pgtable/ppc64: Avoid setting top bits in radom value Aneesh Kumar K.V
2020-08-12  6:40   ` Christophe Leroy
2020-08-12  6:43     ` Aneesh Kumar K.V
2020-08-12  8:12   ` Anshuman Khandual
2020-08-12  8:25     ` Aneesh Kumar K.V
2020-08-12  6:33 ` [PATCH 03/16] debug_vm_pgtable/set_pte: Don't use set_pte_at to update an existing pte entry Aneesh Kumar K.V
2020-08-12  9:12   ` Anshuman Khandual
2020-08-12  9:22     ` Aneesh Kumar K.V
2020-08-12  6:33 ` [PATCH 04/16] debug_vm_pgtables/hugevmap: Use the arch helper to identify huge vmap support Aneesh Kumar K.V
2020-08-12 10:30   ` Anshuman Khandual
2020-08-12  6:33 ` [PATCH 05/16] debug_vm_pgtable/savedwrite: Enable savedwrite test with CONFIG_NUMA_BALANCING Aneesh Kumar K.V
2020-08-12 11:24   ` Anshuman Khandual
2020-08-12  6:33 ` [PATCH 06/16] debug_vm_pgtable/THP: Mark the pte entry huge before using set_pmd_at Aneesh Kumar K.V
2020-08-12  6:33 ` [PATCH 07/16] debug_vm_pgtable/THP: Mark the pte entry huge before using set_pud_at Aneesh Kumar K.V
2020-08-12 11:49   ` Anshuman Khandual
2020-08-12  6:33 ` [PATCH 08/16] debug_vm_pgtable/set_pmd: Don't use set_pmd_at to update an existing pmd entry Aneesh Kumar K.V
2020-08-12 12:46   ` Anshuman Khandual
2020-08-12  6:33 ` [PATCH 09/16] debug_vm_pgtable/set_pud: Don't use set_pud_at to update an existing pud entry Aneesh Kumar K.V
2020-08-12 12:46   ` Anshuman Khandual
2020-08-12  6:33 ` [PATCH 10/16] debug_vm_pgtable/thp: Use page table depost/withdraw with THP Aneesh Kumar K.V
2020-08-13  5:25   ` Anshuman Khandual
2020-08-13  6:38     ` Aneesh Kumar K.V
2020-08-12  6:33 ` [PATCH 11/16] debug_vm_pgtable/locks: Move non page table modifying test together Aneesh Kumar K.V
2020-08-12  6:33 ` [PATCH 12/16] debug_vm_pgtable/locks: Take correct page table lock Aneesh Kumar K.V
2020-08-12  6:33 ` [PATCH 13/16] debug_vm_pgtable/pmd_clear: Don't use pmd/pud_clear on pte entries Aneesh Kumar K.V
2020-08-13  5:27   ` Anshuman Khandual
2020-08-13  8:45     ` Aneesh Kumar K.V
2020-08-12  6:33 ` [PATCH 14/16] debug_vm_pgtable/hugetlb: Disable hugetlb test on ppc64 Aneesh Kumar K.V
2020-08-12 13:03   ` Anshuman Khandual
2020-08-12 13:16     ` Aneesh Kumar K.V
2020-08-12 13:34       ` Anshuman Khandual
2020-08-12 13:52         ` Aneesh Kumar K.V
2020-08-14  8:43           ` Anshuman Khandual
2020-08-19  6:54             ` Aneesh Kumar K.V
2020-08-12  6:33 ` [PATCH 15/16] debug_vm_pgtable/savedwrite: Use savedwrite test with protnone ptes Aneesh Kumar K.V
2020-08-12 13:06   ` Anshuman Khandual
2020-08-12  6:33 ` [PATCH 16/16] debug_vm_pgtable/ppc64: Add a variant of pfn_pte/pmd Aneesh Kumar K.V
2020-08-13  5:30   ` Anshuman Khandual
2020-08-13  6:37     ` Aneesh Kumar K.V
2020-08-14  8:29       ` Anshuman Khandual
2020-08-12  7:46 ` [PATCH 01/16] powerpc/mm: Add DEBUG_VM WARN for pmd_clear Anshuman Khandual
2020-08-12  8:27   ` Aneesh Kumar K.V

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