From patchwork Mon Jan 25 11:45:02 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 60347 Delivered-To: patch@linaro.org Received: by 10.112.130.2 with SMTP id oa2csp1301797lbb; Mon, 25 Jan 2016 03:50:39 -0800 (PST) X-Received: by 10.66.100.198 with SMTP id fa6mr25495738pab.123.1453722636547; Mon, 25 Jan 2016 03:50:36 -0800 (PST) Return-Path: Received: from bombadil.infradead.org (bombadil.infradead.org. [2001:1868:205::9]) by mx.google.com with ESMTPS id m65si33275720pfi.251.2016.01.25.03.50.36 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 25 Jan 2016 03:50:36 -0800 (PST) Received-SPF: pass (google.com: domain of linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org designates 2001:1868:205::9 as permitted sender) client-ip=2001:1868:205::9; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org designates 2001:1868:205::9 as permitted sender) smtp.mailfrom=linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1aNfeJ-0000Yp-Lj; Mon, 25 Jan 2016 11:49:35 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1aNfbb-0006PW-My for linux-arm-kernel@lists.infradead.org; Mon, 25 Jan 2016 11:46:53 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8BC975F5; Mon, 25 Jan 2016 03:45:49 -0800 (PST) Received: from leverpostej.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 715D33F246; Mon, 25 Jan 2016 03:46:28 -0800 (PST) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com Subject: [PATCHv3 08/18] arm64: kasan: avoid TLB conflicts Date: Mon, 25 Jan 2016 11:45:02 +0000 Message-Id: <1453722312-23076-9-git-send-email-mark.rutland@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1453722312-23076-1-git-send-email-mark.rutland@arm.com> References: <1453722312-23076-1-git-send-email-mark.rutland@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160125_034648_101069_38C047B3 X-CRM114-Status: GOOD ( 10.71 ) X-Spam-Score: -6.9 (------) X-Spam-Report: SpamAssassin version 3.4.0 on bombadil.infradead.org summary: Content analysis details: (-6.9 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at http://www.dnswl.org/, high trust [217.140.101.70 listed in list.dnswl.org] -0.0 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -0.0 SPF_PASS SPF: sender matches SPF record -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, lorenzo.pieralisi@arm.com, arnd@arndb.de, ard.biesheuvel@linaro.org, will.deacon@arm.com, jeremy.linton@arm.com, ryabinin.a.a@gmail.com, labbott@fedoraproject.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org The page table modification performed during the KASAN init risks the allocation of conflicting TLB entries, as it swaps a set of valid global entries for another without suitable TLB maintenance. The presence of conflicting TLB entries can result in the delivery of synchronous TLB conflict aborts, or may result in the use of erroneous data being returned in response to a TLB lookup. This can affect explicit data accesses from software as well as translations performed asynchronously (e.g. as part of page table walks or speculative I-cache fetches), and can therefore result in a wide variety of problems. To avoid this, use cpu_replace_ttbr1 to swap the page tables. This ensures that when the new tables are installed there are no stale entries from the old tables which may conflict. As all updates are made to the tables while they are not active, the updates themselves are safe. At the same time, add the missing barrier to ensure that the tmp_pg_dir entries updated via memcpy are visible to the page table walkers at the point the tmp_pg_dir is installed. All other page table updates made as part of KASAN initialisation have the requisite barriers due to the use of the standard page table accessors. Signed-off-by: Mark Rutland Reviewed-by: Catalin Marinas Cc: Andrey Ryabinin Tested-by: Ard Biesheuvel Reviewed-by: Ard Biesheuvel Cc: Jeremy Linton Cc: Laura Abbott Cc: Will Deacon --- arch/arm64/mm/kasan_init.c | 17 ++++------------- 1 file changed, 4 insertions(+), 13 deletions(-) -- 1.9.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c index cf038c7..3e3d280 100644 --- a/arch/arm64/mm/kasan_init.c +++ b/arch/arm64/mm/kasan_init.c @@ -16,6 +16,7 @@ #include #include +#include #include #include #include @@ -108,15 +109,6 @@ static void __init clear_pgds(unsigned long start, set_pgd(pgd_offset_k(start), __pgd(0)); } -static void __init cpu_set_ttbr1(unsigned long ttbr1) -{ - asm( - " msr ttbr1_el1, %0\n" - " isb" - : - : "r" (ttbr1)); -} - void __init kasan_init(void) { struct memblock_region *reg; @@ -129,8 +121,8 @@ void __init kasan_init(void) * setup will be finished. */ memcpy(tmp_pg_dir, swapper_pg_dir, sizeof(tmp_pg_dir)); - cpu_set_ttbr1(__pa(tmp_pg_dir)); - flush_tlb_all(); + dsb(ishst); + cpu_replace_ttbr1(tmp_pg_dir); clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END); @@ -156,8 +148,7 @@ void __init kasan_init(void) } memset(kasan_zero_page, 0, PAGE_SIZE); - cpu_set_ttbr1(__pa(swapper_pg_dir)); - flush_tlb_all(); + cpu_replace_ttbr1(swapper_pg_dir); /* At this point kasan is fully initialized. Enable error messages */ init_task.kasan_depth = 0;