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 X-Spam-Level: X-Spam-Status: No, score=-11.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 82E0DC43457 for ; Mon, 19 Oct 2020 12:23:36 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BC3A422276 for ; Mon, 19 Oct 2020 12:23:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="KNNb2quR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BC3A422276 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id D226E6B0068; Mon, 19 Oct 2020 08:23:34 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CFA306B006C; Mon, 19 Oct 2020 08:23:34 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C36A66B006E; Mon, 19 Oct 2020 08:23:34 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0225.hostedemail.com [216.40.44.225]) by kanga.kvack.org (Postfix) with ESMTP id 987DA6B0068 for ; Mon, 19 Oct 2020 08:23:34 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 1E2B0824CD84 for ; Mon, 19 Oct 2020 12:23:34 +0000 (UTC) X-FDA: 77388590748.30.watch83_280580627237 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin30.hostedemail.com (Postfix) with ESMTP id F0324180B3AA7 for ; Mon, 19 Oct 2020 12:23:33 +0000 (UTC) X-HE-Tag: watch83_280580627237 X-Filterd-Recvd-Size: 4079 Received: from mail-oo1-f66.google.com (mail-oo1-f66.google.com [209.85.161.66]) by imf07.hostedemail.com (Postfix) with ESMTP for ; Mon, 19 Oct 2020 12:23:33 +0000 (UTC) Received: by mail-oo1-f66.google.com with SMTP id f19so2745932oot.4 for ; Mon, 19 Oct 2020 05:23:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=dQ/xkg0nub+4PWvL+CKk+B6D0YwCVYzzs73TSH8kNVQ=; b=KNNb2quRNLavZKnbq84BN09PddtCjLDKY8l1PyePqN5qML8laC3nwaT4NBr6GPVvbT m5hi+ylV5PTV+5yC10AJBXvrs12rCkXvCytqYOrw/J/9HaXCMhs4eCxjzU4NlfxV8OeW cT/aBDM00HfqE4piZMdL3Q+G5PdL6mNzRsJK/DPeHuHnZPWgT6veGAueDDLkhswiVsaS jdi1wuddVSNiBQFt+EDXt7rX5X/BAJ3eSgnp7hR8du7ENJkT2sdHDVfJvkJtZyvOIXda t3PodY9tjcaBiQSD0P3dlMjWpPmRdatAeK8xBAf3ATrED/JrpF04RRRg++k9JCpoiazV Em/g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=dQ/xkg0nub+4PWvL+CKk+B6D0YwCVYzzs73TSH8kNVQ=; b=gWHa26YtHIKS+/BngqU4OsSwZr/mKzoLxZuhbgD5qnwVnFwYD788CsLWznv7e6TKSL gl6hMtGWwx30x02D8EQi8xHLc49+zq1Mi5IJoDEimSNykATpLpMuEqX+smIaKkbmpc3q lLd1KRJTqxA1CRCJ5o7sHJMVSvz+jU16ayWQB6sd6eyDE7YkaX+g9Gzjq2MEpbnDzpgz 9Z2poKCq7HBq+Obty5i5Z+peR8er0kNnglp2qpMHp+1OqaeAZRJQ59hNxllxAPPNmq9L ASrpcFNJJbzNLFj0//o0jVHeeyXyp4jvfjmnKILrXxBGH1Atow7DV5x+4eYqrfnUPTvt uLEQ== X-Gm-Message-State: AOAM5330eei1Mqsv/5F3gTkwlBCwhiKr1Tcryumi9s1ipW1Y2kbBbXNr m8FCawjzDc0GTD/5FuBffCDD6mZNrjSsY+UtFsjo0w== X-Google-Smtp-Source: ABdhPJyzrJGEyTNn3o7Z/7yYsS4rCx6vGVxAMJ4aeGbENvimZAAEsHrHYujEbgneVgAi5nthk0tr5Wqrq/EUItPn75c= X-Received: by 2002:a4a:b28b:: with SMTP id k11mr11874415ooo.54.1603110212494; Mon, 19 Oct 2020 05:23:32 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Marco Elver Date: Mon, 19 Oct 2020 14:23:20 +0200 Message-ID: Subject: Re: [PATCH RFC 0/8] kasan: hardware tag-based mode for production use on arm64 To: Andrey Konovalov Cc: Catalin Marinas , Will Deacon , Vincenzo Frascino , Dmitry Vyukov , Alexander Potapenko , Evgenii Stepanov , Andrey Ryabinin , Elena Petrova , Branislav Rankov , Kevin Brodsky , Andrew Morton , kasan-dev , Linux ARM , Linux Memory Management List , LKML , Serban Constantinescu , Kostya Serebryany Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, 14 Oct 2020 at 22:44, Andrey Konovalov wrote: [...] > A question to KASAN maintainers: what would be the best way to support the > "off" mode? I see two potential approaches: add a check into each kasan > callback (easier to implement, but we still call kasan callbacks, even > though they immediately return), or add inline header wrappers that do the > same. This is tricky, because we don't know how bad the performance will be if we keep them as calls. We'd have to understand the performance impact of keeping them as calls, and if the performance impact is acceptable or not. Without understanding the performance impact, the only viable option I see is to add __always_inline kasan_foo() wrappers, which use the static branch to guard calls to __kasan_foo(). Thanks, -- Marco