From nobody Tue Apr 7 19:54:17 2026 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id BF0D936E49F; Fri, 27 Feb 2026 17:57:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772215057; cv=none; b=JWz8Nj7KtrtJuNfn1LGS45c+mQddftzTJ9IuNlmgXa+MCETRrs8WYHQKhneq5hV25/wzEltLXylxw5sqO2xwLZOWXgBHQaVaUTu8JhvTQmbLvytUAiC9Ha3RBDl+bTZurUto9aMWkXEf6cEgSq0JjzoZHktFm2HRxgWRKaOVWgc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772215057; c=relaxed/simple; bh=P8IDTj4yF6qDQuR+pa/KMXIkjNEeYrDKFCKpXqXY1Pk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pSiRtG/ZtIhi7x0HWaYUwhcZwOP7dVeTQhcjaQBkOH6Hb+pP3HwEYO1zAizvax+6jR/SEyUMvSP3gRBZjMBa91aNNwr6/MXHV90Blq1B46dq0aHtsDcxVXljsH8Z+tbkFq8q8a29o5rnkTB0BiN/kZLqt6+irl4yrTMMi8uQq4w= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CE7E41516; Fri, 27 Feb 2026 09:57:29 -0800 (PST) Received: from e123572-lin.arm.com (e123572-lin.cambridge.arm.com [10.1.194.54]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B8C363F73B; Fri, 27 Feb 2026 09:57:31 -0800 (PST) From: Kevin Brodsky To: linux-hardening@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Kevin Brodsky , Andrew Morton , Andy Lutomirski , Catalin Marinas , Dave Hansen , David Hildenbrand , Ira Weiny , Jann Horn , Jeff Xu , Joey Gouly , Kees Cook , Linus Walleij , Lorenzo Stoakes , Marc Zyngier , Mark Brown , Matthew Wilcox , Maxwell Bland , "Mike Rapoport (IBM)" , Peter Zijlstra , Pierre Langlois , Quentin Perret , Rick Edgecombe , Ryan Roberts , Thomas Gleixner , Vlastimil Babka , Will Deacon , Yang Shi , Yeoreum Yun , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, x86@kernel.org Subject: [PATCH v6 24/30] arm64: kpkeys: Handle splitting of linear map Date: Fri, 27 Feb 2026 17:55:12 +0000 Message-ID: <20260227175518.3728055-25-kevin.brodsky@arm.com> X-Mailer: git-send-email 2.51.2 In-Reply-To: <20260227175518.3728055-1-kevin.brodsky@arm.com> References: <20260227175518.3728055-1-kevin.brodsky@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" When the kpkeys_hardened_pgtables feature is enabled, special care is required when allocating page table pages while splitting the linear map. Indicate that such pages are being allocated by passing __GFP_PGTABLE_SPLIT and use the appropriate interface to prepare the kpkeys_hardened_pgtables allocator in split_kernel_leaf_mapping(). Signed-off-by: Kevin Brodsky --- arch/arm64/mm/mmu.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index ea1cb1875257..2cee0b7f8a56 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -707,7 +707,7 @@ static int split_kernel_leaf_mapping_locked(unsigned lo= ng addr) if (!pud_present(pud)) goto out; if (pud_leaf(pud)) { - ret =3D split_pud(pudp, pud, GFP_PGTABLE_KERNEL, true); + ret =3D split_pud(pudp, pud, GFP_PGTABLE_KERNEL | __GFP_PGTABLE_SPLIT, t= rue); if (ret) goto out; } @@ -732,7 +732,7 @@ static int split_kernel_leaf_mapping_locked(unsigned lo= ng addr) */ if (ALIGN_DOWN(addr, PMD_SIZE) =3D=3D addr) goto out; - ret =3D split_pmd(pmdp, pmd, GFP_PGTABLE_KERNEL, true); + ret =3D split_pmd(pmdp, pmd, GFP_PGTABLE_KERNEL | __GFP_PGTABLE_SPLIT, t= rue); if (ret) goto out; } @@ -800,7 +800,18 @@ int split_kernel_leaf_mapping(unsigned long start, uns= igned long end) if (start !=3D PAGE_ALIGN(start) || end !=3D PAGE_ALIGN(end)) return -EINVAL; =20 +kpkeys_retry: + ret =3D kpkeys_prepare_direct_map_split(); + if (ret) + return ret; + mutex_lock(&pgtable_split_lock); + + if (!kpkeys_ready_for_direct_map_split()) { + mutex_unlock(&pgtable_split_lock); + goto kpkeys_retry; + } + lazy_mmu_mode_enable(); =20 /* --=20 2.51.2