From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id CD2E047A0C4; Wed, 22 Jul 2026 15:32:42 +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=1784734364; cv=none; b=Jz6x4rYCK/TIU6kopsJteMNWaMMywhfHZPWrtD4DSX7XydqBD2HR5eVp3kM8O40H/xaehrFVfMTPFr68E17ldc7QIWgYaNWXucyP9XrJlKIjV2qvdFSzGBNarU7Bla5+ODiboegotMg6WsuE/oSPBc/kX6gBYXexhmtjW823/fc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784734364; c=relaxed/simple; bh=7Ae9Beb4KeYHYFDO2fuqF6aoTpqIj0FluLW/seeBxD4=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=RSDb7KwgKMYmybTz6qWy9GrCsD0VaOsNEezy7HgjLF2PPoLIqfwq0EGI20hvsHAhKAw6MUJdA3WI65KYhHiwUXDp1QDWWSTdZvovQ2FArHdc7ktVg35hGNbIRmf7CFqFu5dAAg7A6zG7SVGYu8CL17pmjENEGNCUevlQ9JNjqc4= 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; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=B0aehDdF; 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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="B0aehDdF" 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 EBCC7168F; Wed, 22 Jul 2026 08:32:37 -0700 (PDT) Received: from e129823.arm.com (e129823.arm.com [10.2.213.3]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 546693F66F; Wed, 22 Jul 2026 08:32:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1784734362; bh=7Ae9Beb4KeYHYFDO2fuqF6aoTpqIj0FluLW/seeBxD4=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=B0aehDdFvBfvBVIIp2zMH67Lgu5JuiYLh/bHJAAXod1jJVYAFkp5Bu1vG2YdKZCzM M0aFKyio40bPpN9seoAqUpmyTQoj/5ClQV8N33uLEYbIpsyIyeUsQ7VEjiJsJYIlX2 a0pvoqex/lEfvtzADdbbAoF90e4wmb3qWVHWRIYw= From: Yeoreum Yun Date: Wed, 22 Jul 2026 16:30:25 +0100 Subject: [PATCH RFC v2 17/20] mm/pgtable: disallow calling (pgd|p4d|pud)_page, pgd_page_vaddr() and (p4d|pud)_pgtable with dummy Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260722-dummy_ptxp3-v2-17-d9e4bad31e0a@arm.com> References: <20260722-dummy_ptxp3-v2-0-d9e4bad31e0a@arm.com> In-Reply-To: <20260722-dummy_ptxp3-v2-0-d9e4bad31e0a@arm.com> To: Russell King , Huacai Chen , WANG Xuerui , Thomas Bogendoerfer , Catalin Marinas , Will Deacon , Arnd Bergmann , Andrew Morton , Kairui Song , Qi Zheng , Shakeel Butt , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Johannes Weiner , David Hildenbrand , Michal Hocko , Lorenzo Stoakes , Tianrui Zhao , Bibo Mao , Anup Patel , Atish Patra , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonas Bonn , Stefan Kristiansson , Stafford Horne Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-openrisc@vger.kernel.org X-Mailer: b4 0.13.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2991; i=yeoreum.yun@arm.com; h=from:subject:message-id; bh=ZfOIqDcnxaLeCJmpu2GHcBUFS7H+BCZkr1Bq1FmACcE=; b=owEB7QES/pANAwAKAW3Vw9FaxTEzAcsmYgBqYOIXWFr4tS39OcpehK5ArSSuOGxsT8KERLcOY bFidb6RmOuJAbMEAAEKAB0WIQQtg+CS3QUzuFh1pJ1t1cPRWsUxMwUCamDiFwAKCRBt1cPRWsUx Mxl5C/4/Z1An+pql6k/RmbweehPJhZeYR2tquIfEoDvMBJSdPiyFbCFjDDF/KEPtFyRTltpsXmj nzAORhubLrsQB4dtTfHleQt6PMQdVMtlXRJulqNEPQ0lMVYC+Ja5vR6TgOM8Xt0xVRH9op3YXV6 XVFwxUasE+yRlaMndg/VFQoVgZ0KZVsEOU5OVbb884+BEebDjXZrWL6y9ayYhKEb1s/ASnpJ40c jpBwvMakWgRS20jzRBXxCWzNF7S9I33l9S8IpU7Vdc4xGcut0KxmytlqFLElSSrXBpBq3hZbef0 R3UlALA31tYedWIXhixSSbGujT4BeJDB6W/iKmmZCGoUR71JyBQyljLM+dNRMWR81Cc8kdEGno/ RRj1wyhyGYC1/hC07KPBcGES4CJ9xA0DCuprgpOcy2/x7Fh6vYNpcPWpse086hcBs731SXQJzI1 RubKkCaWr4hOc32pd3WmnGvIsyxbARqJAr5JzesTLBpGF4nd4m0X533vaNfqsfo8IK0d4= X-Developer-Key: i=yeoreum.yun@arm.com; a=openpgp; fpr=2D83E092DD0533B85875A49D6DD5C3D15AC53133 From: "David Hildenbrand (Arm)" These helpers that silently fallback to the folded level are dangerous, especially with some upcoming changes. Make all code compile-out any calls to these helpers with dummy value. So let's make the compiler complain if these helpers are abused with dummy pXdp value. Signed-off-by: David Hildenbrand (Arm) --- include/asm-generic/pgtable-nop4d.h | 8 ++++++-- include/asm-generic/pgtable-nopmd.h | 8 ++++++-- include/asm-generic/pgtable-nopud.h | 8 ++++++-- 3 files changed, 18 insertions(+), 6 deletions(-) diff --git a/include/asm-generic/pgtable-nop4d.h b/include/asm-generic/pgtable-nop4d.h index 9e9e4557761d..05c3acc0884b 100644 --- a/include/asm-generic/pgtable-nop4d.h +++ b/include/asm-generic/pgtable-nop4d.h @@ -70,8 +70,12 @@ static __always_inline p4d_t *__p4d_offset_lockless(pgd_t *pgdp, pgd_t pgd, #define p4d_val(x) (pgd_val((x).pgd)) #define __p4d(x) ((p4d_t) { __pgd(x) }) -#define pgd_page(pgd) (p4d_page((p4d_t){ pgd })) -#define pgd_page_vaddr(pgd) ((unsigned long)(p4d_pgtable((p4d_t){ pgd }))) +#define pgd_page(pgd) ({ BUILD_BUG(); (struct page *)NULL; }) +#define pgd_page_vaddr(pgd) \ +({ \ + pgd_check_dummy(pgd); \ + (unsigned long)p4d_pgtable((p4d_t) { pgd }); \ +}) /* * allocating and freeing a p4d is trivial: the 1-entry p4d is diff --git a/include/asm-generic/pgtable-nopmd.h b/include/asm-generic/pgtable-nopmd.h index f92ddcea444f..aa4902f63c0e 100644 --- a/include/asm-generic/pgtable-nopmd.h +++ b/include/asm-generic/pgtable-nopmd.h @@ -80,8 +80,12 @@ static __always_inline pmd_t *__pmd_offset_lockless(pud_t *pudp, pud_t pud, #define pmd_val(x) (pud_val((x).pud)) #define __pmd(x) ((pmd_t) { __pud(x) } ) -#define pud_page(pud) (pmd_page((pmd_t){ pud })) -#define pud_pgtable(pud) ((pmd_t *)(pmd_page_vaddr((pmd_t){ pud }))) +#define pud_page(pud) ({ BUILD_BUG(); (struct page *)NULL; }) +#define pud_pgtable(pud) \ +({ \ + pud_check_dummy(pud); \ + ((pmd_t *)(pmd_page_vaddr((pmd_t) { pud }))); \ +}) /* * allocating and freeing a pmd is trivial: the 1-entry pmd is diff --git a/include/asm-generic/pgtable-nopud.h b/include/asm-generic/pgtable-nopud.h index 7475d0bd0f2e..3264673c0c38 100644 --- a/include/asm-generic/pgtable-nopud.h +++ b/include/asm-generic/pgtable-nopud.h @@ -77,8 +77,12 @@ static __always_inline pud_t *__pud_offset_lockless(p4d_t *p4dp, p4d_t p4d, #define pud_val(x) (p4d_val((x).p4d)) #define __pud(x) ((pud_t) { __p4d(x) }) -#define p4d_page(p4d) (pud_page((pud_t){ p4d })) -#define p4d_pgtable(p4d) ((pud_t *)(pud_pgtable((pud_t){ p4d }))) +#define p4d_page(p4d) ({ BUILD_BUG(); (struct page *)NULL; }) +#define p4d_pgtable(p4d) \ +({ \ + p4d_check_dummy(p4d); \ + ((pud_t *)(pud_pgtable((pud_t) { p4d }))); \ +}) /* * allocating and freeing a pud is trivial: the 1-entry pud is -- 2.43.0