From nobody Sun Feb 8 22:06:41 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B544BCA9EA3 for ; Tue, 13 Jun 2023 00:12:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238657AbjFMAMl (ORCPT ); Mon, 12 Jun 2023 20:12:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51900 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237807AbjFMAMW (ORCPT ); Mon, 12 Jun 2023 20:12:22 -0400 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B9A6A19F; Mon, 12 Jun 2023 17:12:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1686615133; x=1718151133; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=HsIyEUzZjyBgsbaXIFC6qpwhsPOWh1g+KPlkVPDuH8M=; b=U8wH8LhsGtKZUHBcEkduZ4nQxDxYGp/RRA3NNcR0f538h25SL7Kazd8w W1LeUkIXENSJmrPyyf4P6GPVl4Nvr7mlFLUAQ4ENyzwhEK0QKP4GHEnbx duiqB68RpY9NYuyBMPKn8eOVu7k1axQoe0+lINjv7xq0re9LIYB5CMASC YNjB4pSNEUWN3DgYyaZXSBb+6eRTjA8TDAx0MIQ9hvBEH4KM25KaHrLXC jck7ynSAZwsWBoOpIEIOx+4M8VaeN3tmAAqRrCna8Z1DMFuzGGCv9xQDN eUnd7gK8NlW20M06T0Qj6VGl5rHUh2kD/yn33VZ/BTS+CFdUJKPYTa9Kn A==; X-IronPort-AV: E=McAfee;i="6600,9927,10739"; a="361556752" X-IronPort-AV: E=Sophos;i="6.00,238,1681196400"; d="scan'208";a="361556752" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jun 2023 17:12:10 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10739"; a="835670984" X-IronPort-AV: E=Sophos;i="6.00,238,1681196400"; d="scan'208";a="835670984" Received: from almeisch-mobl1.amr.corp.intel.com (HELO rpedgeco-desk4.amr.corp.intel.com) ([10.209.42.242]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jun 2023 17:12:09 -0700 From: Rick Edgecombe To: x86@kernel.org, "H . Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H . J . Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , Weijiang Yang , "Kirill A . Shutemov" , John Allen , kcc@google.com, eranian@google.com, rppt@kernel.org, jamorris@linux.microsoft.com, dethoma@microsoft.com, akpm@linux-foundation.org, Andrew.Cooper3@citrix.com, christina.schimpe@intel.com, david@redhat.com, debug@rivosinc.com, szabolcs.nagy@arm.com, torvalds@linux-foundation.org, broonie@kernel.org Cc: rick.p.edgecombe@intel.com, Yu-cheng Yu , Axel Rasmussen , Peter Xu , Pengfei Xu Subject: [PATCH v9 05/42] mm: Move VM_UFFD_MINOR_BIT from 37 to 38 Date: Mon, 12 Jun 2023 17:10:31 -0700 Message-Id: <20230613001108.3040476-6-rick.p.edgecombe@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230613001108.3040476-1-rick.p.edgecombe@intel.com> References: <20230613001108.3040476-1-rick.p.edgecombe@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Yu-cheng Yu The x86 Control-flow Enforcement Technology (CET) feature includes a new type of memory called shadow stack. This shadow stack memory has some unusual properties, which requires some core mm changes to function properly. Future patches will introduce a new VM flag VM_SHADOW_STACK that will be VM_HIGH_ARCH_BIT_5. VM_HIGH_ARCH_BIT_1 through VM_HIGH_ARCH_BIT_4 are bits 32-36, and bit 37 is the unrelated VM_UFFD_MINOR_BIT. For the sake of order, make all VM_HIGH_ARCH_BITs stay together by moving VM_UFFD_MINOR_BIT from 37 to 38. This will allow VM_SHADOW_STACK to be introduced as 37. Signed-off-by: Yu-cheng Yu Co-developed-by: Rick Edgecombe Signed-off-by: Rick Edgecombe Reviewed-by: Borislav Petkov (AMD) Reviewed-by: Kees Cook Reviewed-by: Axel Rasmussen Acked-by: Mike Rapoport (IBM) Acked-by: Peter Xu Tested-by: Pengfei Xu Tested-by: John Allen Tested-by: Kees Cook Reviewed-by: David Hildenbrand --- include/linux/mm.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 9ec20cbb20c1..6f52c1e7c640 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -370,7 +370,7 @@ extern unsigned int kobjsize(const void *objp); #endif =20 #ifdef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR -# define VM_UFFD_MINOR_BIT 37 +# define VM_UFFD_MINOR_BIT 38 # define VM_UFFD_MINOR BIT(VM_UFFD_MINOR_BIT) /* UFFD minor faults */ #else /* !CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */ # define VM_UFFD_MINOR VM_NONE --=20 2.34.1