From nobody Sun Feb 8 18:32:28 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 30E0CC7618A for ; Mon, 20 Mar 2023 16:50:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232156AbjCTQuK (ORCPT ); Mon, 20 Mar 2023 12:50:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231978AbjCTQsf (ORCPT ); Mon, 20 Mar 2023 12:48:35 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B261123118; Mon, 20 Mar 2023 09:41:44 -0700 (PDT) Date: Mon, 20 Mar 2023 16:39:28 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1679330369; 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=E8uckkRhYtGhjYgD1zxfWIMgKATVGBDK2ETEdaGxUl8=; b=iom8daLrTSr6bGyT733yF1WW3ZkKl6gpr7ipm8IMfanapBxhZF6E3TykcPlGjZ8ba1VFmt k5zdAhbjTTJbEE4J5k4P/RUOQZgGNuYtRyrfbMCp3cBWyBRvbzVdKpWR9GB7tp+bnbiWH9 ZDFGwhiuub77hfatWVwVkszVcSHkSEZmNagwLeq91yOPpiyV8gsaB5BOrvVWNE62eroDEx e7HjIysSrZhZGK9Ux3Q7KFGhXTHXyjZ1/dO1C8o1vr64hgTaly+fXE6d50TgRVAcaH6w01 TQ/BE36iR7sNrErzP4rfUgKKgJ7VEqpj4yOj8eljBkgQSoWlqNz/kZ4z++iRuQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1679330369; 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=E8uckkRhYtGhjYgD1zxfWIMgKATVGBDK2ETEdaGxUl8=; b=QUN+yvHDSYewW3b4Z75nIXZQm1lvvTmz+4ZKUzfyHyF6n9QSNvptqA/MuVBb6+YzhGIK8s s5yRM5imlv9yc7Dw== 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] mm: Introduce pte_mkwrite_kernel() Cc: David Hildenbrand , 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: <167933036855.5837.3392895917684573434.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: 2cdecd5f4a15cb5896ea2ca5a8f9408ceb3653db Gitweb: https://git.kernel.org/tip/2cdecd5f4a15cb5896ea2ca5a8f9408ce= b3653db Author: Rick Edgecombe AuthorDate: Sat, 18 Mar 2023 17:15:06 -07:00 Committer: Dave Hansen CommitterDate: Mon, 20 Mar 2023 09:01:09 -07:00 mm: Introduce pte_mkwrite_kernel() 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. One of these changes is to allow for pte_mkwrite() to create different types of writable memory (the existing conventionally writable type and also the new shadow stack type). Future patches will convert pte_mkwrite() to take a VMA in order to facilitate this, however there are places in the kernel where pte_mkwrite() is called outside of the context of a VMA. These are for kernel memory. So create a new variant called pte_mkwrite_kernel() and switch the kernel users over to it. Have pte_mkwrite() and pte_mkwrite_kernel() be the same for now. Future patches will introduce changes to make pte_mkwrite() take a VMA. Only do this for architectures that need it because they call pte_mkwrite() in arch code without an associated VMA. Since it will only currently be used in arch code, so do not include it in arch_pgtable_helpers.rst. Suggested-by: David Hildenbrand 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: David Hildenbrand Acked-by: Deepak Gupta Tested-by: Pengfei Xu Tested-by: John Allen Tested-by: Kees Cook Link: https://lore.kernel.org/lkml/0e29a2d0-08d8-bcd6-ff26-4bea0e4037b0@red= hat.com/ Link: https://lore.kernel.org/all/20230319001535.23210-12-rick.p.edgecombe%= 40intel.com --- arch/arm64/include/asm/pgtable.h | 7 ++++++- arch/arm64/mm/trans_pgd.c | 4 ++-- arch/s390/include/asm/pgtable.h | 7 ++++++- arch/s390/mm/pageattr.c | 2 +- arch/x86/include/asm/pgtable.h | 7 ++++++- arch/x86/xen/mmu_pv.c | 2 +- 6 files changed, 22 insertions(+), 7 deletions(-) diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgta= ble.h index b6ba466..cccf888 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -180,13 +180,18 @@ static inline pmd_t set_pmd_bit(pmd_t pmd, pgprot_t p= rot) return pmd; } =20 -static inline pte_t pte_mkwrite(pte_t pte) +static inline pte_t pte_mkwrite_kernel(pte_t pte) { pte =3D set_pte_bit(pte, __pgprot(PTE_WRITE)); pte =3D clear_pte_bit(pte, __pgprot(PTE_RDONLY)); return pte; } =20 +static inline pte_t pte_mkwrite(pte_t pte) +{ + return pte_mkwrite_kernel(pte); +} + static inline pte_t pte_mkclean(pte_t pte) { pte =3D clear_pte_bit(pte, __pgprot(PTE_DIRTY)); diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c index 4ea2eef..5c07e68 100644 --- a/arch/arm64/mm/trans_pgd.c +++ b/arch/arm64/mm/trans_pgd.c @@ -40,7 +40,7 @@ static void _copy_pte(pte_t *dst_ptep, pte_t *src_ptep, u= nsigned long addr) * read only (code, rodata). Clear the RDONLY bit from * the temporary mappings we use during restore. */ - set_pte(dst_ptep, pte_mkwrite(pte)); + set_pte(dst_ptep, pte_mkwrite_kernel(pte)); } else if (debug_pagealloc_enabled() && !pte_none(pte)) { /* * debug_pagealloc will removed the PTE_VALID bit if @@ -53,7 +53,7 @@ static void _copy_pte(pte_t *dst_ptep, pte_t *src_ptep, u= nsigned long addr) */ BUG_ON(!pfn_valid(pte_pfn(pte))); =20 - set_pte(dst_ptep, pte_mkpresent(pte_mkwrite(pte))); + set_pte(dst_ptep, pte_mkpresent(pte_mkwrite_kernel(pte))); } } =20 diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtabl= e.h index 2c70b4d..d4943f2 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -1005,7 +1005,7 @@ static inline pte_t pte_wrprotect(pte_t pte) return set_pte_bit(pte, __pgprot(_PAGE_PROTECT)); } =20 -static inline pte_t pte_mkwrite(pte_t pte) +static inline pte_t pte_mkwrite_kernel(pte_t pte) { pte =3D set_pte_bit(pte, __pgprot(_PAGE_WRITE)); if (pte_val(pte) & _PAGE_DIRTY) @@ -1013,6 +1013,11 @@ static inline pte_t pte_mkwrite(pte_t pte) return pte; } =20 +static inline pte_t pte_mkwrite(pte_t pte) +{ + return pte_mkwrite_kernel(pte); +} + static inline pte_t pte_mkclean(pte_t pte) { pte =3D clear_pte_bit(pte, __pgprot(_PAGE_DIRTY)); diff --git a/arch/s390/mm/pageattr.c b/arch/s390/mm/pageattr.c index 85195c1..4ee5fe5 100644 --- a/arch/s390/mm/pageattr.c +++ b/arch/s390/mm/pageattr.c @@ -96,7 +96,7 @@ static int walk_pte_level(pmd_t *pmdp, unsigned long addr= , unsigned long end, if (flags & SET_MEMORY_RO) new =3D pte_wrprotect(new); else if (flags & SET_MEMORY_RW) - new =3D pte_mkwrite(pte_mkdirty(new)); + new =3D pte_mkwrite_kernel(pte_mkdirty(new)); if (flags & SET_MEMORY_NX) new =3D set_pte_bit(new, __pgprot(_PAGE_NOEXEC)); else if (flags & SET_MEMORY_X) diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 56eea96..3607f25 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -364,11 +364,16 @@ static inline pte_t pte_mkyoung(pte_t pte) return pte_set_flags(pte, _PAGE_ACCESSED); } =20 -static inline pte_t pte_mkwrite(pte_t pte) +static inline pte_t pte_mkwrite_kernel(pte_t pte) { return pte_set_flags(pte, _PAGE_RW); } =20 +static inline pte_t pte_mkwrite(pte_t pte) +{ + return pte_mkwrite_kernel(pte); +} + static inline pte_t pte_mkhuge(pte_t pte) { return pte_set_flags(pte, _PAGE_PSE); diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c index ee29fb5..a23f042 100644 --- a/arch/x86/xen/mmu_pv.c +++ b/arch/x86/xen/mmu_pv.c @@ -150,7 +150,7 @@ void make_lowmem_page_readwrite(void *vaddr) if (pte =3D=3D NULL) return; /* vaddr missing */ =20 - ptev =3D pte_mkwrite(*pte); + ptev =3D pte_mkwrite_kernel(*pte); =20 if (HYPERVISOR_update_va_mapping(address, ptev, 0)) BUG();