From nobody Sun Feb 8 19:55:00 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 4877DC6FD1D for ; Mon, 20 Mar 2023 16:50:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232373AbjCTQuS (ORCPT ); Mon, 20 Mar 2023 12:50:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46100 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232034AbjCTQt1 (ORCPT ); Mon, 20 Mar 2023 12:49:27 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DDB8E1630B; Mon, 20 Mar 2023 09:41:55 -0700 (PDT) Date: Mon, 20 Mar 2023 16:39:25 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1679330366; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=xGipKE+chYK8KeU0SCLx+62PG4srK5cXRSyRvcj12Mw=; b=Kimqu0HmPy23CqNNiFwgxkHuHAFZo641Sz7cfjv0y8w2OfrkjceZIty9igB0n02mjIOS3R bak4U+5NtTfJCZX4uvk6TNcEGC04BD92usMuyLCEwbRz9thwQ0D4jD5V7ohR5oNbAlkRzO vK7WzHUZ/liLoR+WQ1l+Hb7WmM2kGh2BBlEwGuzKS2PDsUHWGA+CvJCKPL8Au9SDU87N9Z 1PqvfdUn6mRpXDdvb1ajEmLiPwuYvpTmJtNvtfbIK6Fa5c/PpVZBeGT9RxCXyzEVfF+PCC h10AaqMSKPTzpXBlx1burXgQWfmeFzk4Zh7Wbr9C0q62JxFrCop97GJMJ9lS7g== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1679330366; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=xGipKE+chYK8KeU0SCLx+62PG4srK5cXRSyRvcj12Mw=; b=gbSCVNZuIV/aQSQruKJCZOwfwitoUyBGbd3s+C2A+kxBQqNL9777AVxAsptMlfyFwz5Z/p RzeFWaJzMNIs7HCg== From: "tip-bot2 for Rick Edgecombe" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/shstk] x86/mm: Teach pte_mkwrite() about stack memory Cc: Rick Edgecombe , Dave Hansen , "Borislav Petkov (AMD)" , Kees Cook , "Mike Rapoport (IBM)" , Deepak Gupta , Pengfei Xu , John Allen , x86@kernel.org, linux-kernel@vger.kernel.org MIME-Version: 1.0 Message-ID: <167933036578.5837.829340269312083950.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/shstk branch of tip: Commit-ID: a1d44091f03ed23e7e137eaeea3424996c7d72eb Gitweb: https://git.kernel.org/tip/a1d44091f03ed23e7e137eaeea3424996= c7d72eb Author: Rick Edgecombe AuthorDate: Sat, 18 Mar 2023 17:15:15 -07:00 Committer: Dave Hansen CommitterDate: Mon, 20 Mar 2023 09:01:10 -07:00 x86/mm: Teach pte_mkwrite() about stack memory If a VMA has the VM_SHADOW_STACK flag, it is shadow stack memory. So when it is made writable with pte_mkwrite(), it should create shadow stack memory, not conventionally writable memory. Now that all the places where shadow stack memory might be created pass a VMA into pte_mkwrite(), it can know when it should do this. So make pte_mkwrite() create shadow stack memory when the VMA has the VM_SHADOW_STACK flag. Do the same thing for pmd_mkwrite(). This requires referencing VM_SHADOW_STACK in these functions, which are currently defined in pgtable.h, however mm.h (where VM_SHADOW_STACK is located) can't be pulled in without causing problems for files that reference pgtable.h. So also move pte/pmd_mkwrite() into pgtable.c, where they can safely reference VM_SHADOW_STACK. Signed-off-by: Rick Edgecombe Signed-off-by: Dave Hansen Reviewed-by: Borislav Petkov (AMD) Reviewed-by: Kees Cook Acked-by: Mike Rapoport (IBM) Acked-by: Deepak Gupta Tested-by: Pengfei Xu Tested-by: John Allen Tested-by: Kees Cook Link: https://lore.kernel.org/all/20230319001535.23210-21-rick.p.edgecombe%= 40intel.com --- arch/x86/include/asm/pgtable.h | 20 ++------------------ arch/x86/mm/pgtable.c | 26 ++++++++++++++++++++++++++ 2 files changed, 28 insertions(+), 18 deletions(-) diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 05dfdbd..d81e7ec 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -456,15 +456,7 @@ static inline pte_t pte_mkwrite_kernel(pte_t pte) =20 struct vm_area_struct; =20 -static inline pte_t pte_mkwrite(pte_t pte, struct vm_area_struct *vma) -{ - pte =3D pte_mkwrite_kernel(pte); - - if (pte_dirty(pte)) - pte =3D pte_clear_saveddirty(pte); - - return pte; -} +pte_t pte_mkwrite(pte_t pte, struct vm_area_struct *vma); =20 static inline pte_t pte_mkhuge(pte_t pte) { @@ -601,15 +593,7 @@ static inline pmd_t pmd_mkyoung(pmd_t pmd) return pmd_set_flags(pmd, _PAGE_ACCESSED); } =20 -static inline pmd_t pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) -{ - pmd =3D pmd_set_flags(pmd, _PAGE_RW); - - if (pmd_dirty(pmd)) - pmd =3D pmd_clear_saveddirty(pmd); - - return pmd; -} +pmd_t pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma); =20 static inline pud_t pud_set_flags(pud_t pud, pudval_t set) { diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index e4f499e..98856bc 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -880,3 +880,29 @@ int pmd_free_pte_page(pmd_t *pmd, unsigned long addr) =20 #endif /* CONFIG_X86_64 */ #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */ + +pte_t pte_mkwrite(pte_t pte, struct vm_area_struct *vma) +{ + if (vma->vm_flags & VM_SHADOW_STACK) + return pte_mkwrite_shstk(pte); + + pte =3D pte_mkwrite_kernel(pte); + + if (pte_dirty(pte)) + pte =3D pte_clear_saveddirty(pte); + + return pte; +} + +pmd_t pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) +{ + if (vma->vm_flags & VM_SHADOW_STACK) + return pmd_mkwrite_shstk(pmd); + + pmd =3D pmd_set_flags(pmd, _PAGE_RW); + + if (pmd_dirty(pmd)) + pmd =3D pmd_clear_saveddirty(pmd); + + return pmd; +}