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From: James Houghton <jthoughton@google.com>
To: Steve Capper <steve.capper@arm.com>,
	Will Deacon <will@kernel.org>,
	 Andrew Morton <akpm@linux-foundation.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>,
	Muchun Song <songmuchun@bytedance.com>,
	 Anshuman Khandual <anshuman.khandual@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	 Ryan Roberts <ryan.roberts@arm.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	 James Houghton <jthoughton@google.com>
Subject: [PATCH 2/2] arm64: mm: Always make sw-dirty PTEs hw-dirty in pte_modify
Date: Mon,  4 Dec 2023 17:26:46 +0000	[thread overview]
Message-ID: <20231204172646.2541916-3-jthoughton@google.com> (raw)
In-Reply-To: <20231204172646.2541916-1-jthoughton@google.com>

Make it impossible to create a sw-dirty, hw-clean PTE with pte_modify.
Such a PTE should be impossible to create, and there may be places that
assume that pte_dirty() implies pte_hw_dirty().

Signed-off-by: James Houghton <jthoughton@google.com>

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index b19a8aee684c..79ce70fbb751 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -834,6 +834,12 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 		pte = set_pte_bit(pte, __pgprot(PTE_DIRTY));
 
 	pte_val(pte) = (pte_val(pte) & ~mask) | (pgprot_val(newprot) & mask);
+	/*
+	 * If we end up clearing hw dirtiness for a sw-dirty PTE, set hardware
+	 * dirtiness again.
+	 */
+	if (pte_sw_dirty(pte))
+		pte = pte_mkdirty(pte);
 	return pte;
 }
 
-- 
2.43.0.rc2.451.g8631bc7472-goog



  parent reply	other threads:[~2023-12-04 17:27 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-04 17:26 [PATCH 0/2] arm64: hugetlb: Fix page fault loop for sw-dirty/hw-clean contiguous PTEs James Houghton
2023-12-04 17:26 ` [PATCH 1/2] arm64: hugetlb: Distinguish between hw and sw dirtiness in __cont_access_flags_changed James Houghton
2023-12-04 17:26 ` James Houghton [this message]
2023-12-06 10:26   ` [PATCH 2/2] arm64: mm: Always make sw-dirty PTEs hw-dirty in pte_modify Ryan Roberts
2023-12-11 18:42   ` Will Deacon
2023-12-11 19:01     ` James Houghton
2023-12-05 14:43 ` [PATCH 0/2] arm64: hugetlb: Fix page fault loop for sw-dirty/hw-clean contiguous PTEs Ryan Roberts
2023-12-05 17:54   ` James Houghton
2023-12-06 10:24     ` Ryan Roberts
2023-12-06 21:01       ` James Houghton
2023-12-12 17:22 ` (subset) " Catalin Marinas

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