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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=+EYduUcDZi5305eYv3iFGbrJoeNChzA396oztTfjBXU=; b=Ie3E4tpJungX61H9n7UkQgKV3nPGzmxw46bDArgdquOZoCeJt2exuWseNWuWOOEI6f jSeOupW2Sc26wcZTCZAKoE/2jYwKlArd03YwvMAfeUH3nA+D4OfGgO/f+LVQeZW3jR/p RCGzMIW+fN8GgWMcwHl45ph5A1whzvqFvLc2CPA1pQfABvQE64xfsrEG+kkyLsy63o28 +JSofIFh1aZxm28WUnMSPwI/0jhfe/t5lSF0ebDALNnrl/X4siReNrOnUkZPnx5mqe+b dzhdcI9A7xSCeNetEQXPDna1hiYPFks7drpy4L+Y8JNnHSWqPjx9nwnt+rwsJCZJAbYy Fzsg== X-Gm-Message-State: APjAAAUE3Pw2TLisBT1QuQuxwqx3AwFlO4UWJWCmbQUt+hekdVftkK99 tPGG2fXtuzhW01N40yn3QWgomBwJpcHz8/sxUAWNr6BnioM= X-Google-Smtp-Source: APXvYqxP7jBF9PnXnDysL/SrUBCGW3Lv4EcU5tUKWTw5jUIPDgtI/jqhKpKkKz3Y5IvwtOULGC1TyfC1kP6l9kY7Leo= X-Received: by 2002:a5d:4984:: with SMTP id r4mr13660823wrq.137.1576260322155; Fri, 13 Dec 2019 10:05:22 -0800 (PST) MIME-Version: 1.0 References: <20191211184027.20130-1-catalin.marinas@arm.com> In-Reply-To: <20191211184027.20130-1-catalin.marinas@arm.com> From: Peter Collingbourne Date: Fri, 13 Dec 2019 10:05:10 -0800 Message-ID: Subject: Re: [PATCH 00/22] arm64: Memory Tagging Extension user-space support To: Catalin Marinas X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191213_100526_398331_E5404941 X-CRM114-Status: GOOD ( 11.85 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch@vger.kernel.org, Richard Earnshaw , Kostya Kortchinsky , Kostya Serebryany , Szabolcs Nagy , Marc Zyngier , Kevin Brodsky , linux-mm@kvack.org, Evgenii Stepanov , Andrey Konovalov , Vincenzo Frascino , Will Deacon , Linux ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Dec 11, 2019 at 10:40 AM Catalin Marinas wrote: > Hi, > > This series proposes the initial user-space support for the ARMv8.5 > Memory Tagging Extension [1]. Thanks for sending out this series. I have been testing it on Android with the FVP model and my in-development scudo changes that add memory tagging support [1], and have not noticed any problems so far. > - Clarify whether mmap(tagged_addr, PROT_MTE) pre-tags the memory with > the tag given in the tagged_addr hint. Strong justification is > required for this as it would force arm64 to disable the zero page. We would like to use this feature in scudo to tag large (>128KB on Android) allocations, which are currently allocated via mmap rather than from an allocation pool. Otherwise we would need to pay the cost (perf and RSS) of faulting all of their pages at allocation time instead of on demand, if we want to tag them. If we could disable the zero page for tagged mappings only and let the pages be faulted as they are read, that would work for us. Peter [1] https://reviews.llvm.org/D70762 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel