From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f72.google.com (mail-pg0-f72.google.com [74.125.83.72]) by kanga.kvack.org (Postfix) with ESMTP id E6D5F6B0038 for ; Thu, 2 Nov 2017 15:38:06 -0400 (EDT) Received: by mail-pg0-f72.google.com with SMTP id v78so603949pgb.18 for ; Thu, 02 Nov 2017 12:38:06 -0700 (PDT) Received: from mga07.intel.com (mga07.intel.com. [134.134.136.100]) by mx.google.com with ESMTPS id w6si4122162pgb.291.2017.11.02.12.38.05 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 02 Nov 2017 12:38:05 -0700 (PDT) Subject: Re: [PATCH 00/23] KAISER: unmap most of the kernel from userspace page tables References: <20171031223146.6B47C861@viggo.jf.intel.com> <20171102190106.GC22263@arm.com> From: Dave Hansen Message-ID: <816a3491-3c2c-ec0a-810f-b593c25968f2@linux.intel.com> Date: Thu, 2 Nov 2017 12:38:05 -0700 MIME-Version: 1.0 In-Reply-To: <20171102190106.GC22263@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Will Deacon Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org On 11/02/2017 12:01 PM, Will Deacon wrote: > On Tue, Oct 31, 2017 at 03:31:46PM -0700, Dave Hansen wrote: >> KAISER makes it harder to defeat KASLR, but makes syscalls and >> interrupts slower. These patches are based on work from a team at >> Graz University of Technology posted here[1]. The major addition is >> support for Intel PCIDs which builds on top of Andy Lutomorski's PCID >> work merged for 4.14. PCIDs make KAISER's overhead very reasonable >> for a wide variety of use cases. > I just wanted to say that I've got a version of this up and running for > arm64. I'm still ironing out a few small details, but I hope to post it > after the merge window. We always use ASIDs, and the perf impact looks > like it aligns roughly with your findings for a PCID-enabled x86 system. Welcome to the party! I don't know if you've found anything different, but there been woefully little code that's really cross-architecture. The kernel task stack-mapping stuff _was_, but it's going away. The per-cpu-user-mapped section stuff might be common, I guess. Is there any other common infrastructure that we can or should be sharing? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org