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=-15.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 102B2C4361B for ; Mon, 14 Dec 2020 23:51:48 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B771120731 for ; Mon, 14 Dec 2020 23:51:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B771120731 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=1rNAhoOjQLOSsUTpzh3MyLwa0eNwYwYc17bgVcnr/WA=; b=rSzDSpdAKM3hwOGqnGC9YUOlR 6tABCHcctJQx/t1P1iSjTGvk/Kfgjg/DA1N2CrLxrlXINVpVcsy5h+wVTWG1S8wKpHKa96rvu/zF3 THa5wyOe6P3fg6JVCzEFfn2sWGE/N/BLGrZvH0D3JR851FrtKcoW/CKKLMiMJ2tkG/WSXI3VcUBaD g92KELkXXyZ1bU8DrQ2kgGMkvpdOo/Pja4fUw8ziKAZXKBzPuZly3XWYwYYnD87bO1eOwblA6lU2d X8+fE1JbRQ3q7tYcxARAVk9dwkvv+/6+7PacWGLPlStqQvvQ6yoZDCFgph/sURym/cWVEEyXPAvkq KTbTYnpag==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1koxbt-0006hp-OA; Mon, 14 Dec 2020 23:50:33 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1koxbr-0006hT-6G for linux-arm-kernel@lists.infradead.org; Mon, 14 Dec 2020 23:50:31 +0000 Date: Mon, 14 Dec 2020 23:50:24 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1607989830; bh=SJV+58ZVFlykR+8LRz85SA+mdMX5Zhf60lyRr0nr08Q=; h=From:To:Cc:Subject:References:In-Reply-To:From; b=noYICguQ2NPaSUjL8UbaTSj/fY6r5/rKVdP3h/Al4d6IRimcNzEwCphdZ7W0hnMVJ JbYUASrm8lG1k2c0p4w3Euoye4WedxrhjF6Mo7oS36wKTu49cqe50Eju+YVToOJsPD 8JPpfKkmvyYeWnrhvNegQ4GBFpPdivp24+r9MhUiY2ogVuA30uL47yVMYeDwvqqgTd szMVAuBqHFKc7f0ng+7AAVaSfC7qD4l1oA7Ewf/bdXDVapj9BzmlxjWZy1jctH0425 Ro/lNuCmbpco19I2MJbL4M2QigLTTX6sngbKyaLBLHe/HtxPlLfvwLl5UVJBa6SYoi duhngK04mmI2Q== From: Will Deacon To: Ard Biesheuvel Subject: Re: [PATCH] drm/amd/display: Revert "add DCN support for aarch64" Message-ID: <20201214235024.GB14575@willie-the-truck> References: <20201214175225.38975-1-ardb@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201214175225.38975-1-ardb@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201214_185031_310514_FBBE9C75 X-CRM114-Status: GOOD ( 17.86 ) 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: Rob Herring , Leo Li , Catalin Marinas , amd-gfx@lists.freedesktop.org, Christian =?iso-8859-1?Q?K=F6nig?= , David Airlie , dri-devel@lists.freedesktop.org, Daniel Vetter , Daniel Kolesa , Alex Deucher , Dave Martin , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Dec 14, 2020 at 06:52:25PM +0100, Ard Biesheuvel wrote: > This reverts commit c38d444e44badc557cf29fdfdfb823604890ccfa. > = > Simply disabling -mgeneral-regs-only left and right is risky, given that > the standard AArch64 ABI permits the use of FP/SIMD registers anywhere, > and GCC is known to use SIMD registers for spilling, and may invent > other uses of the FP/SIMD register file that have nothing to do with the > floating point code in question. Note that putting kernel_neon_begin() > and kernel_neon_end() around the code that does use FP is not sufficient > here, the problem is in all the other code that may be emitted with > references to SIMD registers in it. > = > So the only way to do this properly is to put all floating point code in > a separate compilation unit, and only compile that unit with > -mgeneral-regs-only. But perhaps the use of floating point here is > something that should be reconsidered entirely. > = > Cc: Catalin Marinas > Cc: Will Deacon > Cc: Dave Martin > Cc: Rob Herring > Cc: Leo Li > Cc: Alex Deucher > Cc: "Christian K=F6nig" > Cc: David Airlie > Cc: Daniel Vetter > Cc: Daniel Kolesa > Cc: amd-gfx@lists.freedesktop.org > Cc: dri-devel@lists.freedesktop.org > Signed-off-by: Ard Biesheuvel > --- > drivers/gpu/drm/amd/display/Kconfig | 2 +- > drivers/gpu/drm/amd/display/dc/calcs/Makefile | 7 -- > drivers/gpu/drm/amd/display/dc/clk_mgr/Makefile | 7 -- > drivers/gpu/drm/amd/display/dc/dcn10/Makefile | 7 -- > drivers/gpu/drm/amd/display/dc/dcn10/dcn10_resource.c | 81 ++++++++-----= ------- > drivers/gpu/drm/amd/display/dc/dcn20/Makefile | 4 - > drivers/gpu/drm/amd/display/dc/dcn21/Makefile | 4 - > drivers/gpu/drm/amd/display/dc/dml/Makefile | 13 ---- > drivers/gpu/drm/amd/display/dc/dsc/Makefile | 5 -- > drivers/gpu/drm/amd/display/dc/os_types.h | 4 - > 10 files changed, 32 insertions(+), 102 deletions(-) I didn't notice we'd enabled this for arm64, but I agree with the reasoning in the commit message, so: Acked-by: Will Deacon The long and short of it is that it is not safe to compile kernel C code without -mgeneral-regs-only on arm64. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel 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=-15.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 BFB7DC2BB48 for ; Mon, 14 Dec 2020 23:50:33 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 783B820731 for ; Mon, 14 Dec 2020 23:50:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 783B820731 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id D52EA89F2A; Mon, 14 Dec 2020 23:50:31 +0000 (UTC) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2D95B89EB4; Mon, 14 Dec 2020 23:50:30 +0000 (UTC) Date: Mon, 14 Dec 2020 23:50:24 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1607989830; bh=SJV+58ZVFlykR+8LRz85SA+mdMX5Zhf60lyRr0nr08Q=; h=From:To:Cc:Subject:References:In-Reply-To:From; b=noYICguQ2NPaSUjL8UbaTSj/fY6r5/rKVdP3h/Al4d6IRimcNzEwCphdZ7W0hnMVJ JbYUASrm8lG1k2c0p4w3Euoye4WedxrhjF6Mo7oS36wKTu49cqe50Eju+YVToOJsPD 8JPpfKkmvyYeWnrhvNegQ4GBFpPdivp24+r9MhUiY2ogVuA30uL47yVMYeDwvqqgTd szMVAuBqHFKc7f0ng+7AAVaSfC7qD4l1oA7Ewf/bdXDVapj9BzmlxjWZy1jctH0425 Ro/lNuCmbpco19I2MJbL4M2QigLTTX6sngbKyaLBLHe/HtxPlLfvwLl5UVJBa6SYoi duhngK04mmI2Q== From: Will Deacon To: Ard Biesheuvel Subject: Re: [PATCH] drm/amd/display: Revert "add DCN support for aarch64" Message-ID: <20201214235024.GB14575@willie-the-truck> References: <20201214175225.38975-1-ardb@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201214175225.38975-1-ardb@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Leo Li , Catalin Marinas , amd-gfx@lists.freedesktop.org, Christian =?iso-8859-1?Q?K=F6nig?= , David Airlie , dri-devel@lists.freedesktop.org, Daniel Kolesa , Alex Deucher , Dave Martin , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Mon, Dec 14, 2020 at 06:52:25PM +0100, Ard Biesheuvel wrote: > This reverts commit c38d444e44badc557cf29fdfdfb823604890ccfa. > = > Simply disabling -mgeneral-regs-only left and right is risky, given that > the standard AArch64 ABI permits the use of FP/SIMD registers anywhere, > and GCC is known to use SIMD registers for spilling, and may invent > other uses of the FP/SIMD register file that have nothing to do with the > floating point code in question. Note that putting kernel_neon_begin() > and kernel_neon_end() around the code that does use FP is not sufficient > here, the problem is in all the other code that may be emitted with > references to SIMD registers in it. > = > So the only way to do this properly is to put all floating point code in > a separate compilation unit, and only compile that unit with > -mgeneral-regs-only. But perhaps the use of floating point here is > something that should be reconsidered entirely. > = > Cc: Catalin Marinas > Cc: Will Deacon > Cc: Dave Martin > Cc: Rob Herring > Cc: Leo Li > Cc: Alex Deucher > Cc: "Christian K=F6nig" > Cc: David Airlie > Cc: Daniel Vetter > Cc: Daniel Kolesa > Cc: amd-gfx@lists.freedesktop.org > Cc: dri-devel@lists.freedesktop.org > Signed-off-by: Ard Biesheuvel > --- > drivers/gpu/drm/amd/display/Kconfig | 2 +- > drivers/gpu/drm/amd/display/dc/calcs/Makefile | 7 -- > drivers/gpu/drm/amd/display/dc/clk_mgr/Makefile | 7 -- > drivers/gpu/drm/amd/display/dc/dcn10/Makefile | 7 -- > drivers/gpu/drm/amd/display/dc/dcn10/dcn10_resource.c | 81 ++++++++-----= ------- > drivers/gpu/drm/amd/display/dc/dcn20/Makefile | 4 - > drivers/gpu/drm/amd/display/dc/dcn21/Makefile | 4 - > drivers/gpu/drm/amd/display/dc/dml/Makefile | 13 ---- > drivers/gpu/drm/amd/display/dc/dsc/Makefile | 5 -- > drivers/gpu/drm/amd/display/dc/os_types.h | 4 - > 10 files changed, 32 insertions(+), 102 deletions(-) I didn't notice we'd enabled this for arm64, but I agree with the reasoning in the commit message, so: Acked-by: Will Deacon The long and short of it is that it is not safe to compile kernel C code without -mgeneral-regs-only on arm64. Will _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel 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=-15.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 5D882C4361B for ; Mon, 14 Dec 2020 23:50:32 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 18C6F2074B for ; Mon, 14 Dec 2020 23:50:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 18C6F2074B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=amd-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id AE7D689EB4; Mon, 14 Dec 2020 23:50:31 +0000 (UTC) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2D95B89EB4; Mon, 14 Dec 2020 23:50:30 +0000 (UTC) Date: Mon, 14 Dec 2020 23:50:24 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1607989830; bh=SJV+58ZVFlykR+8LRz85SA+mdMX5Zhf60lyRr0nr08Q=; h=From:To:Cc:Subject:References:In-Reply-To:From; b=noYICguQ2NPaSUjL8UbaTSj/fY6r5/rKVdP3h/Al4d6IRimcNzEwCphdZ7W0hnMVJ JbYUASrm8lG1k2c0p4w3Euoye4WedxrhjF6Mo7oS36wKTu49cqe50Eju+YVToOJsPD 8JPpfKkmvyYeWnrhvNegQ4GBFpPdivp24+r9MhUiY2ogVuA30uL47yVMYeDwvqqgTd szMVAuBqHFKc7f0ng+7AAVaSfC7qD4l1oA7Ewf/bdXDVapj9BzmlxjWZy1jctH0425 Ro/lNuCmbpco19I2MJbL4M2QigLTTX6sngbKyaLBLHe/HtxPlLfvwLl5UVJBa6SYoi duhngK04mmI2Q== From: Will Deacon To: Ard Biesheuvel Subject: Re: [PATCH] drm/amd/display: Revert "add DCN support for aarch64" Message-ID: <20201214235024.GB14575@willie-the-truck> References: <20201214175225.38975-1-ardb@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201214175225.38975-1-ardb@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-BeenThere: amd-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion list for AMD gfx List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Rob Herring , Leo Li , Catalin Marinas , amd-gfx@lists.freedesktop.org, Christian =?iso-8859-1?Q?K=F6nig?= , David Airlie , dri-devel@lists.freedesktop.org, Daniel Vetter , Daniel Kolesa , Alex Deucher , Dave Martin , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Errors-To: amd-gfx-bounces@lists.freedesktop.org Sender: "amd-gfx" On Mon, Dec 14, 2020 at 06:52:25PM +0100, Ard Biesheuvel wrote: > This reverts commit c38d444e44badc557cf29fdfdfb823604890ccfa. > = > Simply disabling -mgeneral-regs-only left and right is risky, given that > the standard AArch64 ABI permits the use of FP/SIMD registers anywhere, > and GCC is known to use SIMD registers for spilling, and may invent > other uses of the FP/SIMD register file that have nothing to do with the > floating point code in question. Note that putting kernel_neon_begin() > and kernel_neon_end() around the code that does use FP is not sufficient > here, the problem is in all the other code that may be emitted with > references to SIMD registers in it. > = > So the only way to do this properly is to put all floating point code in > a separate compilation unit, and only compile that unit with > -mgeneral-regs-only. But perhaps the use of floating point here is > something that should be reconsidered entirely. > = > Cc: Catalin Marinas > Cc: Will Deacon > Cc: Dave Martin > Cc: Rob Herring > Cc: Leo Li > Cc: Alex Deucher > Cc: "Christian K=F6nig" > Cc: David Airlie > Cc: Daniel Vetter > Cc: Daniel Kolesa > Cc: amd-gfx@lists.freedesktop.org > Cc: dri-devel@lists.freedesktop.org > Signed-off-by: Ard Biesheuvel > --- > drivers/gpu/drm/amd/display/Kconfig | 2 +- > drivers/gpu/drm/amd/display/dc/calcs/Makefile | 7 -- > drivers/gpu/drm/amd/display/dc/clk_mgr/Makefile | 7 -- > drivers/gpu/drm/amd/display/dc/dcn10/Makefile | 7 -- > drivers/gpu/drm/amd/display/dc/dcn10/dcn10_resource.c | 81 ++++++++-----= ------- > drivers/gpu/drm/amd/display/dc/dcn20/Makefile | 4 - > drivers/gpu/drm/amd/display/dc/dcn21/Makefile | 4 - > drivers/gpu/drm/amd/display/dc/dml/Makefile | 13 ---- > drivers/gpu/drm/amd/display/dc/dsc/Makefile | 5 -- > drivers/gpu/drm/amd/display/dc/os_types.h | 4 - > 10 files changed, 32 insertions(+), 102 deletions(-) I didn't notice we'd enabled this for arm64, but I agree with the reasoning in the commit message, so: Acked-by: Will Deacon The long and short of it is that it is not safe to compile kernel C code without -mgeneral-regs-only on arm64. Will _______________________________________________ amd-gfx mailing list amd-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/amd-gfx