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Sun, 15 Nov 2026 13:36:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794749773; bh=9e6OmEAnqWbjzLHCKKsv84JklwVJ8NC6NYkY8/hHdTo=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=Snqw70srUBsDiPj0zDExRjLpznGGJOqGIBDMhIL+rlIy0RTHPt0RW0gen1S1uIXzD QTnCD4JXzQJh1r1+PPrgca3KW4gKyRYXQ+UAwLtnECG3ghBmfQLGrIf7RKGSI935gp EP4t0w7M8b/KEfLi5aITguxi416bR7NN4F84g+C3b89VMOI4IbHT/C2uhrE2r/W3H9 KwC7JnxPU8fdL/2ToRZlQsRkRHYQOj3vHa/D9sZu5311NqD1rRb5kPqFTWuTSRVfXW I7pAycrtkBGTnD2Ez9QpD+ZHMtOt3ohpsiJBVdyRUV1RXDC8lXPTtb4u4NMEPqfHFl W76a4v1WZmgrA== Date: Sun, 15 Nov 2026 21:15:54 +0800 From: Jisheng Zhang To: "Mike Rapoport (Microsoft)" Cc: Albert Ou , Palmer Dabbelt , Paul Walmsley , Alexandre Ghiti , linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH 2/2] riscv: mm: check the valid bit in kernel_page_present() Message-ID: References: <20261112-fixes-riscv-v1-0-1caac19897b5@kernel.org> <20261112-fixes-riscv-v1-2-1caac19897b5@kernel.org> X-Archived-By: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20261112-fixes-riscv-v1-2-1caac19897b5@kernel.org> X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" X-Spam-Status: No, score=-13.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Thu, Nov 12, 2026 at 03:42:19PM +0200, Mike Rapoport (Microsoft) wrote: > set_direct_map_invalid_noflush() clears _PAGE_PRESENT, but the kernel > mappings keep _PAGE_PROT_NONE set: it used to be _PAGE_READ and now it is > the same bit as _PAGE_GLOBAL. pte_present() and pmd_present() still > return true for the invalidated entry. kernel_page_present() then reports > that an unmapped page is mapped, and hibernation copies it without > remapping it first. > > Test _PAGE_PRESENT directly for PMD and PTE leaves. > > Fixes: 32a0de886eb3 ("arch, mm: make kernel_page_present() always available") > Signed-off-by: Mike Rapoport (Microsoft) > --- > arch/riscv/mm/pageattr.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/arch/riscv/mm/pageattr.c b/arch/riscv/mm/pageattr.c > index b138113755359..62fbcf7cf36b6 100644 > --- a/arch/riscv/mm/pageattr.c > +++ b/arch/riscv/mm/pageattr.c > @@ -453,8 +453,9 @@ bool kernel_page_present(struct page *page) > if (!pmd_present(pmdp_get(pmd))) > return false; > if (pmd_leaf(pmdp_get(pmd))) > - return true; > + return pmd_val(pmdp_get(pmd)) & _PAGE_PRESENT; so we call pmdp_get() up to 3 times, could we save its result and reuse it? > > + /* pte_present() is true for PAGE_KERNEL with _PAGE_PRESENT cleared */ > pte = pte_offset_kernel(pmd, addr); > - return pte_present(ptep_get(pte)); > + return pte_val(ptep_get(pte)) & _PAGE_PRESENT; > } > > -- > 2.53.0 > > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794749773; b=Ra8wpFiKw4EsHbm7fNk2qWrc+dcKvWAr0G4JQFqYf05+NYu/Ycxw2l/mkCIZYCUVIbJ+ FGperRymT1A1XcSufLrZdt2Uf3Z5B8FOeDOXujLc/sLxLk9W2lXul3eHqqAg4lweIFiM+ oG/FtHJO9yWr8hoKpWMfw5TO9jYL/n5l2JZXMMvjvNTNu1+RTp6r4RFC9ncwZev2cD8go gs4aydPtHMT10TgywBMlMG9y4ro3t6MgPtPJsTIfLOUSskSWiteKRi2w5I+xDtT72BXcC YqX2B+lOHUkZlvgDHhywNlIVluIONPaLKYGqqlrsWko0exwAQR5pmr4hG6sEVFfoiEQ== ARC-Message-Signature: i=1; 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Sun, 15 Nov 2026 13:36:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Snqw70sr Received: by smtp.kernel.org (Postfix) with ESMTPSA id 24EF01F000C4; Sun, 15 Nov 2026 13:36:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794749773; bh=9e6OmEAnqWbjzLHCKKsv84JklwVJ8NC6NYkY8/hHdTo=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=Snqw70srUBsDiPj0zDExRjLpznGGJOqGIBDMhIL+rlIy0RTHPt0RW0gen1S1uIXzD QTnCD4JXzQJh1r1+PPrgca3KW4gKyRYXQ+UAwLtnECG3ghBmfQLGrIf7RKGSI935gp EP4t0w7M8b/KEfLi5aITguxi416bR7NN4F84g+C3b89VMOI4IbHT/C2uhrE2r/W3H9 KwC7JnxPU8fdL/2ToRZlQsRkRHYQOj3vHa/D9sZu5311NqD1rRb5kPqFTWuTSRVfXW I7pAycrtkBGTnD2Ez9QpD+ZHMtOt3ohpsiJBVdyRUV1RXDC8lXPTtb4u4NMEPqfHFl W76a4v1WZmgrA== Date: Sun, 15 Nov 2026 21:15:54 +0800 From: Jisheng Zhang To: "Mike Rapoport (Microsoft)" Cc: Albert Ou , Palmer Dabbelt , Paul Walmsley , Alexandre Ghiti , linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH 2/2] riscv: mm: check the valid bit in kernel_page_present() Message-ID: References: <20261112-fixes-riscv-v1-0-1caac19897b5@kernel.org> <20261112-fixes-riscv-v1-2-1caac19897b5@kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20261112-fixes-riscv-v1-2-1caac19897b5@kernel.org> On Thu, Nov 12, 2026 at 03:42:19PM +0200, Mike Rapoport (Microsoft) wrote: > set_direct_map_invalid_noflush() clears _PAGE_PRESENT, but the kernel > mappings keep _PAGE_PROT_NONE set: it used to be _PAGE_READ and now it is > the same bit as _PAGE_GLOBAL. pte_present() and pmd_present() still > return true for the invalidated entry. kernel_page_present() then reports > that an unmapped page is mapped, and hibernation copies it without > remapping it first. > > Test _PAGE_PRESENT directly for PMD and PTE leaves. > > Fixes: 32a0de886eb3 ("arch, mm: make kernel_page_present() always available") > Signed-off-by: Mike Rapoport (Microsoft) > --- > arch/riscv/mm/pageattr.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/arch/riscv/mm/pageattr.c b/arch/riscv/mm/pageattr.c > index b138113755359..62fbcf7cf36b6 100644 > --- a/arch/riscv/mm/pageattr.c > +++ b/arch/riscv/mm/pageattr.c > @@ -453,8 +453,9 @@ bool kernel_page_present(struct page *page) > if (!pmd_present(pmdp_get(pmd))) > return false; > if (pmd_leaf(pmdp_get(pmd))) > - return true; > + return pmd_val(pmdp_get(pmd)) & _PAGE_PRESENT; so we call pmdp_get() up to 3 times, could we save its result and reuse it? > > + /* pte_present() is true for PAGE_KERNEL with _PAGE_PRESENT cleared */ > pte = pte_offset_kernel(pmd, addr); > - return pte_present(ptep_get(pte)); > + return pte_val(ptep_get(pte)) & _PAGE_PRESENT; > } > > -- > 2.53.0 > > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv