From mboxrd@z Thu Jan 1 00:00:00 1970 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 77B10C28CF5 for ; Wed, 26 Jan 2022 17:30:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243727AbiAZRaf (ORCPT ); Wed, 26 Jan 2022 12:30:35 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:58282 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243708AbiAZRae (ORCPT ); Wed, 26 Jan 2022 12:30:34 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 798C561B14 for ; Wed, 26 Jan 2022 17:30:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A5052C340E7; Wed, 26 Jan 2022 17:30:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1643218233; bh=pO2QvUUsV5L71fd/N5ug5v8ZnpkBMeHmPsJTXFD+MSg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=h4mWX3z03gi8sHlG0EWbH3tBlmtzj7tvg3DWAos6nt50rpnSz+y4Eo/8029jByzvN 1QS6bxsqkew7z6/g9AMZR9VyY1rGyCZIpSGhsDL6MXG2ly75+IVJGMwbP5qQNQmnc5 niDLO7NXIvS8SW/sS+Iu9RE0rgtq1yAVtlynnyHMK3kjdKVHWSzzxx/9fq5DpWQKYu uFouCpefIDGbxSjJ6uLwAvPlD+k/rnpTUE5yE4RTjHp/v/t7Y/50IOKA0+6mcFKqkS bDbWFaatfMikrY8xjz63C104GtDmitiWGq6t64sFVO6JZD8B1suaQ4ed7Ix0FOkLFJ ZqUY+QNom/i5Q== From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org Cc: kvmarm@lists.cs.columbia.edu, linux-hardening@vger.kernel.org, Ard Biesheuvel , Will Deacon , Marc Zyngier , Fuad Tabba , Quentin Perret , Mark Rutland , James Morse , Catalin Marinas Subject: [RFC PATCH 05/12] arm64: mm: remap PUD pages r/o in linear region Date: Wed, 26 Jan 2022 18:30:04 +0100 Message-Id: <20220126173011.3476262-6-ardb@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220126173011.3476262-1-ardb@kernel.org> References: <20220126173011.3476262-1-ardb@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2436; h=from:subject; bh=pO2QvUUsV5L71fd/N5ug5v8ZnpkBMeHmPsJTXFD+MSg=; b=owEB7QES/pANAwAKAcNPIjmS2Y8kAcsmYgBh8YUVOOEJY4XVWRP3L+tY2Fd1rYmhhe86Q8f7AUSQ xXjIo1iJAbMEAAEKAB0WIQT72WJ8QGnJQhU3VynDTyI5ktmPJAUCYfGFFQAKCRDDTyI5ktmPJM0SC/ 9TJASSXr7BX76TnGrR6DVfOMgm4ePZMcUwkFtSUNvrQSheHkJ5Dhpn+wTwQ4G4uEaCrIvhsyhtOJXn gIAqHwx4C2T9W1b3QHf9d5i2c6OXAwWavoJbXb8Hc6W5hBuUylZ+Sb0Aksn1COSPDrNZKn8uB8hGIC /Qea52bWHMwHQdXM1FX2hlKl0SgwrSoyI5HhgMYMQSZJAm8smM6XDsjvXKXwerEg6thIIg3owWG3lp NDAgAmCQu7Se96JZUEYEQoTpGuVBpz4Z2RpNgEMGOCLwfvDDRV9g6cdh9xx+09jia6i0HYga3glYgY AkYpFuapogYWP+/BG6trhpDrEoW8nGh94AxbjdrhxuodEwdGEVg/uE4n4b7ytd6I6UmU5Uq2mUl6PC fhsWIcI82knyV4QIBwfu020onGbyrADdPL9XzuLKgXlr2lVwZmxWs342yn7MxpTq/Y6K5LZqFL6php ii5PZEXG/T7oY+AlBemmzo9R20Bdx0Xcgthq3RHGGaox4= X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org Implement the arch specific PUD alloc/free helpers by wrapping the generic code, and remapping the page read-only on allocation and read-write on free. Signed-off-by: Ard Biesheuvel --- arch/arm64/include/asm/pgalloc.h | 5 +++++ arch/arm64/include/asm/tlb.h | 2 ++ arch/arm64/mm/mmu.c | 20 ++++++++++++++++++++ 3 files changed, 27 insertions(+) diff --git a/arch/arm64/include/asm/pgalloc.h b/arch/arm64/include/asm/pgalloc.h index d54ac9f8d6c7..737e9f32b199 100644 --- a/arch/arm64/include/asm/pgalloc.h +++ b/arch/arm64/include/asm/pgalloc.h @@ -14,6 +14,8 @@ #include #define __HAVE_ARCH_PGD_FREE +#define __HAVE_ARCH_PUD_ALLOC_ONE +#define __HAVE_ARCH_PUD_FREE #include #define PGD_SIZE (PTRS_PER_PGD * sizeof(pgd_t)) @@ -45,6 +47,9 @@ static inline void __pud_populate(pud_t *pudp, phys_addr_t pmdp, pudval_t prot) #if CONFIG_PGTABLE_LEVELS > 3 +pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr); +void pud_free(struct mm_struct *mm, pud_t *pud); + static inline void __p4d_populate(p4d_t *p4dp, phys_addr_t pudp, p4dval_t prot) { set_p4d(p4dp, __p4d(__phys_to_p4d_val(pudp) | prot)); diff --git a/arch/arm64/include/asm/tlb.h b/arch/arm64/include/asm/tlb.h index c995d1f4594f..6557626752fc 100644 --- a/arch/arm64/include/asm/tlb.h +++ b/arch/arm64/include/asm/tlb.h @@ -94,6 +94,8 @@ static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp, static inline void __pud_free_tlb(struct mmu_gather *tlb, pud_t *pudp, unsigned long addr) { + if (page_tables_are_ro()) + set_pgtable_rw(pudp); tlb_remove_table(tlb, virt_to_page(pudp)); } #endif diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index a52c3162beae..03d77c4c3570 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1645,3 +1645,23 @@ static int __init prevent_bootmem_remove_init(void) } early_initcall(prevent_bootmem_remove_init); #endif + +#ifndef __PAGETABLE_PUD_FOLDED +pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr) +{ + pud_t *pud = __pud_alloc_one(mm, addr); + + if (!pud) + return NULL; + if (page_tables_are_ro()) + set_pgtable_ro(pud); + return pud; +} + +void pud_free(struct mm_struct *mm, pud_t *pud) +{ + if (page_tables_are_ro()) + set_pgtable_rw(pud); + free_page((u64)pud); +} +#endif -- 2.30.2