From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932929AbdKQSuV (ORCPT ); Fri, 17 Nov 2017 13:50:21 -0500 Received: from mail-io0-f181.google.com ([209.85.223.181]:33962 "EHLO mail-io0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756447AbdKQSuA (ORCPT ); Fri, 17 Nov 2017 13:50:00 -0500 X-Google-Smtp-Source: AGs4zMaNjjtXqpX4YizAt0fjP0EGfGpdy2gRjHxUA0ncXWmJKgCEE4ysA0XpksJH7+aEoD+7zxTWtA== Date: Fri, 17 Nov 2017 10:49:55 -0800 From: Sami Tolvanen To: Ard Biesheuvel Cc: Will Deacon , Mark Rutland , Andi Kleen , Kees Cook , linux-kbuild@vger.kernel.org, Nick Desaulniers , "linux-kernel@vger.kernel.org" , Greg Hackmann , Masahiro Yamada , Michal Marek , Yury Norov , Alex Matveev , Matthias Kaehlcke , "linux-arm-kernel@lists.infradead.org" , Maxim Kuvyrkov Subject: Re: [PATCH v2 08/18] arm64: don't disable ADR_PREL_PG_HI21* with ARM64_ERRATUM_843419 Message-ID: <20171117184955.GA39391@samitolvanen.mtv.corp.google.com> References: <20171116114406.GB9361@arm.com> <20171116163132.GC94341@samitolvanen.mtv.corp.google.com> <20171116213702.GA10616@samitolvanen.mtv.corp.google.com> <20171116230939.GA38360@samitolvanen.mtv.corp.google.com> <20171116235019.GA55530@samitolvanen.mtv.corp.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 17, 2017 at 09:54:48AM +0000, Ard Biesheuvel wrote: > OK, so all IR objects are converted into a single .o file > encapsulating the module image. Does this give the same benefits as > LTO linking IR objects to a fully linked executable? Yes, it does. > Even if it does, partial linking is not something the toolchain > people are usually crazy about, so it would be nice to have some > confirmation that this is a usage model that is fully supported. I confirmed with our LLVM developers that while this is less common, it's fully supported. I will also drop this patch in v3 as passing code model to LLVMgold fixes the issue with LTO. Sami From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f182.google.com ([209.85.223.182]:42520 "EHLO mail-io0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756444AbdKQSuA (ORCPT ); Fri, 17 Nov 2017 13:50:00 -0500 Received: by mail-io0-f182.google.com with SMTP id u42so9715386ioi.9 for ; Fri, 17 Nov 2017 10:50:00 -0800 (PST) Date: Fri, 17 Nov 2017 10:49:55 -0800 From: Sami Tolvanen Subject: Re: [PATCH v2 08/18] arm64: don't disable ADR_PREL_PG_HI21* with ARM64_ERRATUM_843419 Message-ID: <20171117184955.GA39391@samitolvanen.mtv.corp.google.com> References: <20171116114406.GB9361@arm.com> <20171116163132.GC94341@samitolvanen.mtv.corp.google.com> <20171116213702.GA10616@samitolvanen.mtv.corp.google.com> <20171116230939.GA38360@samitolvanen.mtv.corp.google.com> <20171116235019.GA55530@samitolvanen.mtv.corp.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kbuild-owner@vger.kernel.org List-ID: To: Ard Biesheuvel Cc: Will Deacon , Mark Rutland , Andi Kleen , Kees Cook , linux-kbuild@vger.kernel.org, Nick Desaulniers , "linux-kernel@vger.kernel.org" , Greg Hackmann , Masahiro Yamada , Michal Marek , Yury Norov , Alex Matveev , Matthias Kaehlcke , "linux-arm-kernel@lists.infradead.org" , Maxim Kuvyrkov On Fri, Nov 17, 2017 at 09:54:48AM +0000, Ard Biesheuvel wrote: > OK, so all IR objects are converted into a single .o file > encapsulating the module image. Does this give the same benefits as > LTO linking IR objects to a fully linked executable? Yes, it does. > Even if it does, partial linking is not something the toolchain > people are usually crazy about, so it would be nice to have some > confirmation that this is a usage model that is fully supported. I confirmed with our LLVM developers that while this is less common, it's fully supported. I will also drop this patch in v3 as passing code model to LLVMgold fixes the issue with LTO. Sami From mboxrd@z Thu Jan 1 00:00:00 1970 From: samitolvanen@google.com (Sami Tolvanen) Date: Fri, 17 Nov 2017 10:49:55 -0800 Subject: [PATCH v2 08/18] arm64: don't disable ADR_PREL_PG_HI21* with ARM64_ERRATUM_843419 In-Reply-To: References: <20171116114406.GB9361@arm.com> <20171116163132.GC94341@samitolvanen.mtv.corp.google.com> <20171116213702.GA10616@samitolvanen.mtv.corp.google.com> <20171116230939.GA38360@samitolvanen.mtv.corp.google.com> <20171116235019.GA55530@samitolvanen.mtv.corp.google.com> Message-ID: <20171117184955.GA39391@samitolvanen.mtv.corp.google.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Nov 17, 2017 at 09:54:48AM +0000, Ard Biesheuvel wrote: > OK, so all IR objects are converted into a single .o file > encapsulating the module image. Does this give the same benefits as > LTO linking IR objects to a fully linked executable? Yes, it does. > Even if it does, partial linking is not something the toolchain > people are usually crazy about, so it would be nice to have some > confirmation that this is a usage model that is fully supported. I confirmed with our LLVM developers that while this is less common, it's fully supported. I will also drop this patch in v3 as passing code model to LLVMgold fixes the issue with LTO. Sami