From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King - ARM Linux Subject: Re: [PATCH] Extract initrd free logic from arch-specific code. Date: Thu, 29 Mar 2018 16:27:49 +0100 Message-ID: <20180329152749.GC16141@n2100.armlinux.org.uk> References: <20180325221853.10839-1-shea@shealevy.com> <20180328152714.6103-1-shea@shealevy.com> <05620fee-e8b5-0668-77b8-da073dc78c40@landley.net> <20180328164813.GA3888@n2100.armlinux.org.uk> <20180328221401.GA14084@n2100.armlinux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.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=LGDg/QOAAJpsDz9revNXwfQoBOf1buk3Pn/Qsaw7at0=; b=kyNHtjXZHbMcW6 /01BFBSLKKXFn4DpjznZPnI0fKMDJwk83WlVRhZRN4+QbkMbeWFMNkbWGDWHit9DHmpS+x+1UM1Hy IDGzx/hKLegTMEaUVqyaMvdi2M86MRywL8O8bcoJwr94GFV1uERVkbTP96QOjA3OIfqklY+8lw55d aoRhROKlc9UXyNzrbDigzMqMBY3CZ25+1fXYYN9ZdWoStslr1/cxteHIqQBglBI/nmlGUl2v/I8T3 ItFIQJkgZUmq/v85kIwAcXOn8vUIGwRF+DiS2ZJO96grmPQ1lEFlEd6hagZUEOL3HTJshllGQQnBi V4d0x8/7qY6/cjOdjdOQ==; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2014; h=Sender:In-Reply-To:Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date; bh=tszDhZ36qEhT+cbTS7MjWHFiFTBM6apHylUvgVhpCDU=; b=ePCJ3cfQtbtO22sc7en39ZLcmdH6emq7dEEGhg8fX1MiI/9AhxLwBaq+AYg6OMAKCFubi1fxiKN2DQnIkFutq/xQEwTsmyb/8OGs3gV/QxEUBhhthVlav3Q4rZ7ZJnSA+UawAPxOjnrdYrWzXt2cauVD3gcKrBe2An01ICmGxzI=; Content-Disposition: inline In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-snps-arc" Errors-To: linux-snps-arc-bounces+gla-linux-snps-arc=m.gmane.org@lists.infradead.org To: Oliver Cc: linux-mips@linux-mips.org, linux-sh@vger.kernel.org, Benjamin Herrenschmidt , Linus Walleij , Will Deacon , Paul Mackerras , Michael Ellerman , "James E.J. Bottomley" , Christoph Hellwig , Geert Uytterhoeven , Catalin Marinas , Matt Turner , Eugeniy Paltsev , uclinux-h8-devel@lists.sourceforge.jp, Vladimir Murzin , Marc Zyngier , adi-buildroot-devel@lists.sourceforge.net, Nicholas Piggin , Al Viro , Thomas Gleixner , Richard Henderson , linux-cris-kernel@axis.com, Greg Kroah-Hartman On Thu, Mar 29, 2018 at 09:37:52AM +1100, Oliver wrote: > On Thu, Mar 29, 2018 at 9:14 AM, Russell King - ARM Linux > wrote: > > On Wed, Mar 28, 2018 at 02:04:22PM -0500, Rob Landley wrote: > >> > >> > >> On 03/28/2018 11:48 AM, Russell King - ARM Linux wrote: > >> > On Wed, Mar 28, 2018 at 10:58:51AM -0500, Rob Landley wrote: > >> >> On 03/28/2018 10:26 AM, Shea Levy wrote: > >> >>> Now only those architectures that have custom initrd free requirements > >> >>> need to define free_initrd_mem. > >> >> ... > >> >>> --- a/arch/arc/mm/init.c > >> >>> +++ b/arch/arc/mm/init.c > >> >>> @@ -229,10 +229,3 @@ void __ref free_initmem(void) > >> >>> { > >> >>> free_initmem_default(-1); > >> >>> } > >> >>> - > >> >>> -#ifdef CONFIG_BLK_DEV_INITRD > >> >>> -void __init free_initrd_mem(unsigned long start, unsigned long end) > >> >>> -{ > >> >>> - free_reserved_area((void *)start, (void *)end, -1, "initrd"); > >> >>> -} > >> >>> -#endif > >> >>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > >> >>> index 3f972e83909b..19d1c5594e2d 100644 > >> >>> --- a/arch/arm/Kconfig > >> >>> +++ b/arch/arm/Kconfig > >> >>> @@ -47,6 +47,7 @@ config ARM > >> >>> select HARDIRQS_SW_RESEND > >> >>> select HAVE_ARCH_AUDITSYSCALL if (AEABI && !OABI_COMPAT) > >> >>> select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6 > >> >>> + select HAVE_ARCH_FREE_INITRD_MEM > >> >>> select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU > >> >>> select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU > >> >>> select HAVE_ARCH_MMAP_RND_BITS if MMU > >> >> > >> >> Isn't this why weak symbols were invented? > >> > > >> > Weak symbols means that we end up with both the weakly-referenced code > >> > and the arch code in the kernel image. That's fine if the weak code > >> > is small. > >> > >> The kernel's been able to build with link time garbage collection since 2016: > >> > >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b67067f1176d > >> > >> Wouldn't that remove the unused one? > > > > Probably, if anyone bothered to use that, which they don't. > > > > LD_DEAD_CODE_DATA_ELIMINATION is a symbol without a prompt, and from > > what I can see, nothing selects it. Therefore, the symbol is always > > disabled, and so the feature never gets used in mainline kernels. > > > > Brings up the obvious question - why is it there if it's completely > > unused? (Maybe to cause confusion, and allowing a justification > > for __weak ?) > > IIRC Nick had some patches to do the arch enablement for powerpc, but > I'm not sure what happened to them though. I suspect it just fell down > Nick's ever growing TODO list. I've given it a go on ARM, marking every linker-built table with KEEP() and comparing the System.map files. The resulting kernel is around 150k smaller, which seems good. However, it doesn't boot - and I don't know why. Booting the kernel under kvmtool in a VM using virtio-console, I can find no way to get any kernel messages out of it. Using lkvm debug, I can see that the PC is stuck inside die(), and that's the only information I have. It dies before bringing up the other CPUs, so it's a very early death. I don't think other console types are available under ARM64. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up According to speedtest.net: 8.21Mbps down 510kbps up From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Thu, 29 Mar 2018 17:29:37 +0200 (CEST) Received: from pandora.armlinux.org.uk ([IPv6:2001:4d48:ad52:3201:214:fdff:fe10:1be6]:46070 "EHLO pandora.armlinux.org.uk" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S23990408AbeC2P33aHPxE (ORCPT ); Thu, 29 Mar 2018 17:29:29 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2014; h=Sender:In-Reply-To:Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date; bh=tszDhZ36qEhT+cbTS7MjWHFiFTBM6apHylUvgVhpCDU=; b=ePCJ3cfQtbtO22sc7en39ZLcmdH6emq7dEEGhg8fX1MiI/9AhxLwBaq+AYg6OMAKCFubi1fxiKN2DQnIkFutq/xQEwTsmyb/8OGs3gV/QxEUBhhthVlav3Q4rZ7ZJnSA+UawAPxOjnrdYrWzXt2cauVD3gcKrBe2An01ICmGxzI=; Received: from n2100.armlinux.org.uk ([2002:4e20:1eda:1:214:fdff:fe10:4f86]:55809) by pandora.armlinux.org.uk with esmtpsa (TLSv1.2:AES128-GCM-SHA256:128) (Exim 4.82_1-5b7a7c0-XX) (envelope-from ) id 1f1ZSz-0008NJ-DD; Thu, 29 Mar 2018 16:27:53 +0100 Received: from linux by n2100.armlinux.org.uk with local (Exim 4.82_1-5b7a7c0-XX) (envelope-from ) id 1f1ZSw-0005aR-49; Thu, 29 Mar 2018 16:27:50 +0100 Date: Thu, 29 Mar 2018 16:27:49 +0100 From: Russell King - ARM Linux To: Oliver Cc: Rob Landley , Shea Levy , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Christoph Hellwig , Richard Henderson , Ivan Kokshaysky , Matt Turner , Vineet Gupta , Catalin Marinas , Will Deacon , Mark Salter , Aurelien Jacquiot , Mikael Starvik , Jesper Nilsson , Yoshinori Sato , Richard Kuo , Tony Luck , Fenghua Yu , Geert Uytterhoeven , James Hogan , Michal Simek , Ralf Baechle , David Howells , Ley Foon Tan , Jonas Bonn , Stefan Kristiansson , Stafford Horne , "James E.J. Bottomley" , Helge Deller , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Palmer Dabbelt , Albert Ou , Martin Schwidefsky , Heiko Carstens , Chen Liqin , Lennox Wu , Rich Felker , "David S. Miller" , Jeff Dike , Richard Weinberger , Guan Xuetao , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Chris Zankel , Max Filippov , Kate Stewart , Greg Kroah-Hartman , Philippe Ombredanne , Eugeniy Paltsev , Al Viro , Vladimir Murzin , Linus Walleij , Michal Hocko , Andrew Morton , Sudip Mukherjee , Marc Zyngier , Rob Herring , Kees Cook , Vlastimil Babka , Balbir Singh , Christophe Leroy , Joe Perches , Dan Williams , Wei Yang , Christian =?iso-8859-1?Q?K=F6nig?= , Arnd Bergmann , Deepa Dinamani , Daniel Thompson , Florian Fainelli , linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, adi-buildroot-devel@lists.sourceforge.net, linux-c6x-dev@linux-c6x.org, linux-cris-kernel@axis.com, uclinux-h8-devel@lists.sourceforge.jp, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-metag@vger.kernel.org, linux-mips@linux-mips.org, linux-am33-list@redhat.com, nios2-dev@lists.rocketboards.org, openrisc@lists.librecores.org, linux-parisc@vger.kernel.org, linuxppc-dev , linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net, linux-xtensa@linux-xtensa.org, Nicholas Piggin Subject: Re: [PATCH] Extract initrd free logic from arch-specific code. Message-ID: <20180329152749.GC16141@n2100.armlinux.org.uk> References: <20180325221853.10839-1-shea@shealevy.com> <20180328152714.6103-1-shea@shealevy.com> <05620fee-e8b5-0668-77b8-da073dc78c40@landley.net> <20180328164813.GA3888@n2100.armlinux.org.uk> <20180328221401.GA14084@n2100.armlinux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 63338 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: linux@armlinux.org.uk Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips On Thu, Mar 29, 2018 at 09:37:52AM +1100, Oliver wrote: > On Thu, Mar 29, 2018 at 9:14 AM, Russell King - ARM Linux > wrote: > > On Wed, Mar 28, 2018 at 02:04:22PM -0500, Rob Landley wrote: > >> > >> > >> On 03/28/2018 11:48 AM, Russell King - ARM Linux wrote: > >> > On Wed, Mar 28, 2018 at 10:58:51AM -0500, Rob Landley wrote: > >> >> On 03/28/2018 10:26 AM, Shea Levy wrote: > >> >>> Now only those architectures that have custom initrd free requirements > >> >>> need to define free_initrd_mem. > >> >> ... > >> >>> --- a/arch/arc/mm/init.c > >> >>> +++ b/arch/arc/mm/init.c > >> >>> @@ -229,10 +229,3 @@ void __ref free_initmem(void) > >> >>> { > >> >>> free_initmem_default(-1); > >> >>> } > >> >>> - > >> >>> -#ifdef CONFIG_BLK_DEV_INITRD > >> >>> -void __init free_initrd_mem(unsigned long start, unsigned long end) > >> >>> -{ > >> >>> - free_reserved_area((void *)start, (void *)end, -1, "initrd"); > >> >>> -} > >> >>> -#endif > >> >>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > >> >>> index 3f972e83909b..19d1c5594e2d 100644 > >> >>> --- a/arch/arm/Kconfig > >> >>> +++ b/arch/arm/Kconfig > >> >>> @@ -47,6 +47,7 @@ config ARM > >> >>> select HARDIRQS_SW_RESEND > >> >>> select HAVE_ARCH_AUDITSYSCALL if (AEABI && !OABI_COMPAT) > >> >>> select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6 > >> >>> + select HAVE_ARCH_FREE_INITRD_MEM > >> >>> select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU > >> >>> select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU > >> >>> select HAVE_ARCH_MMAP_RND_BITS if MMU > >> >> > >> >> Isn't this why weak symbols were invented? > >> > > >> > Weak symbols means that we end up with both the weakly-referenced code > >> > and the arch code in the kernel image. That's fine if the weak code > >> > is small. > >> > >> The kernel's been able to build with link time garbage collection since 2016: > >> > >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b67067f1176d > >> > >> Wouldn't that remove the unused one? > > > > Probably, if anyone bothered to use that, which they don't. > > > > LD_DEAD_CODE_DATA_ELIMINATION is a symbol without a prompt, and from > > what I can see, nothing selects it. Therefore, the symbol is always > > disabled, and so the feature never gets used in mainline kernels. > > > > Brings up the obvious question - why is it there if it's completely > > unused? (Maybe to cause confusion, and allowing a justification > > for __weak ?) > > IIRC Nick had some patches to do the arch enablement for powerpc, but > I'm not sure what happened to them though. I suspect it just fell down > Nick's ever growing TODO list. I've given it a go on ARM, marking every linker-built table with KEEP() and comparing the System.map files. The resulting kernel is around 150k smaller, which seems good. However, it doesn't boot - and I don't know why. Booting the kernel under kvmtool in a VM using virtio-console, I can find no way to get any kernel messages out of it. Using lkvm debug, I can see that the PC is stuck inside die(), and that's the only information I have. It dies before bringing up the other CPUs, so it's a very early death. I don't think other console types are available under ARM64. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up According to speedtest.net: 8.21Mbps down 510kbps up From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King - ARM Linux Subject: Re: [PATCH] Extract initrd free logic from arch-specific code. Date: Thu, 29 Mar 2018 16:27:49 +0100 Message-ID: <20180329152749.GC16141@n2100.armlinux.org.uk> References: <20180325221853.10839-1-shea@shealevy.com> <20180328152714.6103-1-shea@shealevy.com> <05620fee-e8b5-0668-77b8-da073dc78c40@landley.net> <20180328164813.GA3888@n2100.armlinux.org.uk> <20180328221401.GA14084@n2100.armlinux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: linux-mips@linux-mips.org, linux-sh@vger.kernel.org, Benjamin Herrenschmidt , Linus Walleij , Will Deacon , Paul Mackerras , Michael Ellerman , "James E.J. Bottomley" , Christoph Hellwig , Geert Uytterhoeven , Catalin Marinas , Matt Turner , Eugeniy Paltsev , uclinux-h8-devel@lists.sourceforge.jp, Vladimir Murzin , Marc Zyngier , adi-buildroot-devel@lists.sourceforge.net, Nicholas Piggin , Al Viro , Thomas Gleixner , Richard Henderson , linux-cris-kernel@axis.com, Greg Kroah-Hartman Return-path: In-Reply-To: List-Id: Linux on Synopsys ARC Processors List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-snps-arc-bounces+gla-linux-snps-arc=m.gmane.org@lists.infradead.org On Thu, Mar 29, 2018 at 09:37:52AM +1100, Oliver wrote: > On Thu, Mar 29, 2018 at 9:14 AM, Russell King - ARM Linux > wrote: > > On Wed, Mar 28, 2018 at 02:04:22PM -0500, Rob Landley wrote: > >> > >> > >> On 03/28/2018 11:48 AM, Russell King - ARM Linux wrote: > >> > On Wed, Mar 28, 2018 at 10:58:51AM -0500, Rob Landley wrote: > >> >> On 03/28/2018 10:26 AM, Shea Levy wrote: > >> >>> Now only those architectures that have custom initrd free requirements > >> >>> need to define free_initrd_mem. > >> >> ... > >> >>> --- a/arch/arc/mm/init.c > >> >>> +++ b/arch/arc/mm/init.c > >> >>> @@ -229,10 +229,3 @@ void __ref free_initmem(void) > >> >>> { > >> >>> free_initmem_default(-1); > >> >>> } > >> >>> - > >> >>> -#ifdef CONFIG_BLK_DEV_INITRD > >> >>> -void __init free_initrd_mem(unsigned long start, unsigned long end) > >> >>> -{ > >> >>> - free_reserved_area((void *)start, (void *)end, -1, "initrd"); > >> >>> -} > >> >>> -#endif > >> >>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > >> >>> index 3f972e83909b..19d1c5594e2d 100644 > >> >>> --- a/arch/arm/Kconfig > >> >>> +++ b/arch/arm/Kconfig > >> >>> @@ -47,6 +47,7 @@ config ARM > >> >>> select HARDIRQS_SW_RESEND > >> >>> select HAVE_ARCH_AUDITSYSCALL if (AEABI && !OABI_COMPAT) > >> >>> select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6 > >> >>> + select HAVE_ARCH_FREE_INITRD_MEM > >> >>> select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU > >> >>> select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU > >> >>> select HAVE_ARCH_MMAP_RND_BITS if MMU > >> >> > >> >> Isn't this why weak symbols were invented? > >> > > >> > Weak symbols means that we end up with both the weakly-referenced code > >> > and the arch code in the kernel image. That's fine if the weak code > >> > is small. > >> > >> The kernel's been able to build with link time garbage collection since 2016: > >> > >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b67067f1176d > >> > >> Wouldn't that remove the unused one? > > > > Probably, if anyone bothered to use that, which they don't. > > > > LD_DEAD_CODE_DATA_ELIMINATION is a symbol without a prompt, and from > > what I can see, nothing selects it. Therefore, the symbol is always > > disabled, and so the feature never gets used in mainline kernels. > > > > Brings up the obvious question - why is it there if it's completely > > unused? (Maybe to cause confusion, and allowing a justification > > for __weak ?) > > IIRC Nick had some patches to do the arch enablement for powerpc, but > I'm not sure what happened to them though. I suspect it just fell down > Nick's ever growing TODO list. I've given it a go on ARM, marking every linker-built table with KEEP() and comparing the System.map files. The resulting kernel is around 150k smaller, which seems good. However, it doesn't boot - and I don't know why. Booting the kernel under kvmtool in a VM using virtio-console, I can find no way to get any kernel messages out of it. Using lkvm debug, I can see that the PC is stuck inside die(), and that's the only information I have. It dies before bringing up the other CPUs, so it's a very early death. I don't think other console types are available under ARM64. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up According to speedtest.net: 8.21Mbps down 510kbps up From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@armlinux.org.uk (Russell King - ARM Linux) Date: Thu, 29 Mar 2018 16:27:49 +0100 Subject: [PATCH] Extract initrd free logic from arch-specific code. In-Reply-To: References: <20180325221853.10839-1-shea@shealevy.com> <20180328152714.6103-1-shea@shealevy.com> <05620fee-e8b5-0668-77b8-da073dc78c40@landley.net> <20180328164813.GA3888@n2100.armlinux.org.uk> <20180328221401.GA14084@n2100.armlinux.org.uk> Message-ID: <20180329152749.GC16141@n2100.armlinux.org.uk> To: linux-riscv@lists.infradead.org List-Id: linux-riscv.lists.infradead.org On Thu, Mar 29, 2018 at 09:37:52AM +1100, Oliver wrote: > On Thu, Mar 29, 2018 at 9:14 AM, Russell King - ARM Linux > wrote: > > On Wed, Mar 28, 2018 at 02:04:22PM -0500, Rob Landley wrote: > >> > >> > >> On 03/28/2018 11:48 AM, Russell King - ARM Linux wrote: > >> > On Wed, Mar 28, 2018 at 10:58:51AM -0500, Rob Landley wrote: > >> >> On 03/28/2018 10:26 AM, Shea Levy wrote: > >> >>> Now only those architectures that have custom initrd free requirements > >> >>> need to define free_initrd_mem. > >> >> ... > >> >>> --- a/arch/arc/mm/init.c > >> >>> +++ b/arch/arc/mm/init.c > >> >>> @@ -229,10 +229,3 @@ void __ref free_initmem(void) > >> >>> { > >> >>> free_initmem_default(-1); > >> >>> } > >> >>> - > >> >>> -#ifdef CONFIG_BLK_DEV_INITRD > >> >>> -void __init free_initrd_mem(unsigned long start, unsigned long end) > >> >>> -{ > >> >>> - free_reserved_area((void *)start, (void *)end, -1, "initrd"); > >> >>> -} > >> >>> -#endif > >> >>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > >> >>> index 3f972e83909b..19d1c5594e2d 100644 > >> >>> --- a/arch/arm/Kconfig > >> >>> +++ b/arch/arm/Kconfig > >> >>> @@ -47,6 +47,7 @@ config ARM > >> >>> select HARDIRQS_SW_RESEND > >> >>> select HAVE_ARCH_AUDITSYSCALL if (AEABI && !OABI_COMPAT) > >> >>> select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6 > >> >>> + select HAVE_ARCH_FREE_INITRD_MEM > >> >>> select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU > >> >>> select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU > >> >>> select HAVE_ARCH_MMAP_RND_BITS if MMU > >> >> > >> >> Isn't this why weak symbols were invented? > >> > > >> > Weak symbols means that we end up with both the weakly-referenced code > >> > and the arch code in the kernel image. That's fine if the weak code > >> > is small. > >> > >> The kernel's been able to build with link time garbage collection since 2016: > >> > >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b67067f1176d > >> > >> Wouldn't that remove the unused one? > > > > Probably, if anyone bothered to use that, which they don't. > > > > LD_DEAD_CODE_DATA_ELIMINATION is a symbol without a prompt, and from > > what I can see, nothing selects it. Therefore, the symbol is always > > disabled, and so the feature never gets used in mainline kernels. > > > > Brings up the obvious question - why is it there if it's completely > > unused? (Maybe to cause confusion, and allowing a justification > > for __weak ?) > > IIRC Nick had some patches to do the arch enablement for powerpc, but > I'm not sure what happened to them though. I suspect it just fell down > Nick's ever growing TODO list. I've given it a go on ARM, marking every linker-built table with KEEP() and comparing the System.map files. The resulting kernel is around 150k smaller, which seems good. However, it doesn't boot - and I don't know why. Booting the kernel under kvmtool in a VM using virtio-console, I can find no way to get any kernel messages out of it. Using lkvm debug, I can see that the PC is stuck inside die(), and that's the only information I have. It dies before bringing up the other CPUs, so it's a very early death. I don't think other console types are available under ARM64. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up According to speedtest.net: 8.21Mbps down 510kbps up From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@armlinux.org.uk (Russell King - ARM Linux) Date: Thu, 29 Mar 2018 16:27:49 +0100 Subject: [PATCH] Extract initrd free logic from arch-specific code. In-Reply-To: References: <20180325221853.10839-1-shea@shealevy.com> <20180328152714.6103-1-shea@shealevy.com> <05620fee-e8b5-0668-77b8-da073dc78c40@landley.net> <20180328164813.GA3888@n2100.armlinux.org.uk> <20180328221401.GA14084@n2100.armlinux.org.uk> List-ID: Message-ID: <20180329152749.GC16141@n2100.armlinux.org.uk> To: linux-snps-arc@lists.infradead.org On Thu, Mar 29, 2018@09:37:52AM +1100, Oliver wrote: > On Thu, Mar 29, 2018 at 9:14 AM, Russell King - ARM Linux > wrote: > > On Wed, Mar 28, 2018@02:04:22PM -0500, Rob Landley wrote: > >> > >> > >> On 03/28/2018 11:48 AM, Russell King - ARM Linux wrote: > >> > On Wed, Mar 28, 2018@10:58:51AM -0500, Rob Landley wrote: > >> >> On 03/28/2018 10:26 AM, Shea Levy wrote: > >> >>> Now only those architectures that have custom initrd free requirements > >> >>> need to define free_initrd_mem. > >> >> ... > >> >>> --- a/arch/arc/mm/init.c > >> >>> +++ b/arch/arc/mm/init.c > >> >>> @@ -229,10 +229,3 @@ void __ref free_initmem(void) > >> >>> { > >> >>> free_initmem_default(-1); > >> >>> } > >> >>> - > >> >>> -#ifdef CONFIG_BLK_DEV_INITRD > >> >>> -void __init free_initrd_mem(unsigned long start, unsigned long end) > >> >>> -{ > >> >>> - free_reserved_area((void *)start, (void *)end, -1, "initrd"); > >> >>> -} > >> >>> -#endif > >> >>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > >> >>> index 3f972e83909b..19d1c5594e2d 100644 > >> >>> --- a/arch/arm/Kconfig > >> >>> +++ b/arch/arm/Kconfig > >> >>> @@ -47,6 +47,7 @@ config ARM > >> >>> select HARDIRQS_SW_RESEND > >> >>> select HAVE_ARCH_AUDITSYSCALL if (AEABI && !OABI_COMPAT) > >> >>> select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6 > >> >>> + select HAVE_ARCH_FREE_INITRD_MEM > >> >>> select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU > >> >>> select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU > >> >>> select HAVE_ARCH_MMAP_RND_BITS if MMU > >> >> > >> >> Isn't this why weak symbols were invented? > >> > > >> > Weak symbols means that we end up with both the weakly-referenced code > >> > and the arch code in the kernel image. That's fine if the weak code > >> > is small. > >> > >> The kernel's been able to build with link time garbage collection since 2016: > >> > >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b67067f1176d > >> > >> Wouldn't that remove the unused one? > > > > Probably, if anyone bothered to use that, which they don't. > > > > LD_DEAD_CODE_DATA_ELIMINATION is a symbol without a prompt, and from > > what I can see, nothing selects it. Therefore, the symbol is always > > disabled, and so the feature never gets used in mainline kernels. > > > > Brings up the obvious question - why is it there if it's completely > > unused? (Maybe to cause confusion, and allowing a justification > > for __weak ?) > > IIRC Nick had some patches to do the arch enablement for powerpc, but > I'm not sure what happened to them though. I suspect it just fell down > Nick's ever growing TODO list. I've given it a go on ARM, marking every linker-built table with KEEP() and comparing the System.map files. The resulting kernel is around 150k smaller, which seems good. However, it doesn't boot - and I don't know why. Booting the kernel under kvmtool in a VM using virtio-console, I can find no way to get any kernel messages out of it. Using lkvm debug, I can see that the PC is stuck inside die(), and that's the only information I have. It dies before bringing up the other CPUs, so it's a very early death. I don't think other console types are available under ARM64. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up According to speedtest.net: 8.21Mbps down 510kbps up From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King - ARM Linux Date: Thu, 29 Mar 2018 16:27:49 +0100 Subject: [OpenRISC] [PATCH] Extract initrd free logic from arch-specific code. In-Reply-To: References: <20180325221853.10839-1-shea@shealevy.com> <20180328152714.6103-1-shea@shealevy.com> <05620fee-e8b5-0668-77b8-da073dc78c40@landley.net> <20180328164813.GA3888@n2100.armlinux.org.uk> <20180328221401.GA14084@n2100.armlinux.org.uk> Message-ID: <20180329152749.GC16141@n2100.armlinux.org.uk> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: openrisc@lists.librecores.org On Thu, Mar 29, 2018 at 09:37:52AM +1100, Oliver wrote: > On Thu, Mar 29, 2018 at 9:14 AM, Russell King - ARM Linux > wrote: > > On Wed, Mar 28, 2018 at 02:04:22PM -0500, Rob Landley wrote: > >> > >> > >> On 03/28/2018 11:48 AM, Russell King - ARM Linux wrote: > >> > On Wed, Mar 28, 2018 at 10:58:51AM -0500, Rob Landley wrote: > >> >> On 03/28/2018 10:26 AM, Shea Levy wrote: > >> >>> Now only those architectures that have custom initrd free requirements > >> >>> need to define free_initrd_mem. > >> >> ... > >> >>> --- a/arch/arc/mm/init.c > >> >>> +++ b/arch/arc/mm/init.c > >> >>> @@ -229,10 +229,3 @@ void __ref free_initmem(void) > >> >>> { > >> >>> free_initmem_default(-1); > >> >>> } > >> >>> - > >> >>> -#ifdef CONFIG_BLK_DEV_INITRD > >> >>> -void __init free_initrd_mem(unsigned long start, unsigned long end) > >> >>> -{ > >> >>> - free_reserved_area((void *)start, (void *)end, -1, "initrd"); > >> >>> -} > >> >>> -#endif > >> >>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > >> >>> index 3f972e83909b..19d1c5594e2d 100644 > >> >>> --- a/arch/arm/Kconfig > >> >>> +++ b/arch/arm/Kconfig > >> >>> @@ -47,6 +47,7 @@ config ARM > >> >>> select HARDIRQS_SW_RESEND > >> >>> select HAVE_ARCH_AUDITSYSCALL if (AEABI && !OABI_COMPAT) > >> >>> select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6 > >> >>> + select HAVE_ARCH_FREE_INITRD_MEM > >> >>> select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU > >> >>> select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU > >> >>> select HAVE_ARCH_MMAP_RND_BITS if MMU > >> >> > >> >> Isn't this why weak symbols were invented? > >> > > >> > Weak symbols means that we end up with both the weakly-referenced code > >> > and the arch code in the kernel image. That's fine if the weak code > >> > is small. > >> > >> The kernel's been able to build with link time garbage collection since 2016: > >> > >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b67067f1176d > >> > >> Wouldn't that remove the unused one? > > > > Probably, if anyone bothered to use that, which they don't. > > > > LD_DEAD_CODE_DATA_ELIMINATION is a symbol without a prompt, and from > > what I can see, nothing selects it. Therefore, the symbol is always > > disabled, and so the feature never gets used in mainline kernels. > > > > Brings up the obvious question - why is it there if it's completely > > unused? (Maybe to cause confusion, and allowing a justification > > for __weak ?) > > IIRC Nick had some patches to do the arch enablement for powerpc, but > I'm not sure what happened to them though. I suspect it just fell down > Nick's ever growing TODO list. I've given it a go on ARM, marking every linker-built table with KEEP() and comparing the System.map files. The resulting kernel is around 150k smaller, which seems good. However, it doesn't boot - and I don't know why. Booting the kernel under kvmtool in a VM using virtio-console, I can find no way to get any kernel messages out of it. Using lkvm debug, I can see that the PC is stuck inside die(), and that's the only information I have. It dies before bringing up the other CPUs, so it's a very early death. I don't think other console types are available under ARM64. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up According to speedtest.net: 8.21Mbps down 510kbps up