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: Wed, 28 Mar 2018 23:14:01 +0100 Message-ID: <20180328221401.GA14084@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> 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=im6eBNoLN8sJoeINblQuxwBG+MYWEvTDfpP356YKkAY=; b=tGsVYspHaAVDjH 1X7QYBH2N0/yozSsAXExCY5sT6ud5sipnsl44MyaZFv29tkEVg6cxjeTkWxpy7Sp9mRCUvP5tirFw i/6LyvO3MHg4B7LTK0sauRoRzV1nqPa/XBB5twPleUUiOEeoqPpuzKvm7lK+ATGUl6PZcWX3mFpVf 0RhISQS6bzAMQ1l76CJ8oSi/CW6vj5YcuVTmlPmq8vL17RdQ2ZM4EJGBkGYKddje30WyEI8eUvLu1 Lwm/JclmfxO6bCcCHmE3R2gDHqctmrYcEhoUQ8pe92K7Jd45Ij0Z0xgaHfmV7OylKE7ftQMA7pHIa 0ECnItYdcLsNP3Y2G6pA==; 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=R6l9I6PvsGbX3NE2xRpmi4yASMm+0pIHUA/D+Vv+P84=; b=gbjR2kk0bv40X9QfjiyNwJUX+5CjStVha/r8BvT9SY4wV5HUGisePY5s6tPYBYEm0VGPJySPFzIPt/PqVBHN/X6+NGAqj7OwAN0i64GlJcfzglZnIuB0Z9JyJv4qZwv6GBbe2N1ntc/rREwqT2LeBvoTBHZ0VqO3lC+PdYPTz7k=; 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: Rob Landley 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, Al Viro , Thomas Gleixner , Richard Henderson , linux-cris-kernel@axis.com, Greg Kroah-Hartman , linux-kernel@vger.kerne 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 ?) -- 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 00:15:58 +0200 (CEST) Received: from pandora.armlinux.org.uk ([IPv6:2001:4d48:ad52:3201:214:fdff:fe10:1be6]:34262 "EHLO pandora.armlinux.org.uk" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S23994591AbeC1WPuzqPzM (ORCPT ); Thu, 29 Mar 2018 00:15:50 +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=R6l9I6PvsGbX3NE2xRpmi4yASMm+0pIHUA/D+Vv+P84=; b=gbjR2kk0bv40X9QfjiyNwJUX+5CjStVha/r8BvT9SY4wV5HUGisePY5s6tPYBYEm0VGPJySPFzIPt/PqVBHN/X6+NGAqj7OwAN0i64GlJcfzglZnIuB0Z9JyJv4qZwv6GBbe2N1ntc/rREwqT2LeBvoTBHZ0VqO3lC+PdYPTz7k=; Received: from n2100.armlinux.org.uk ([2001:4d48:ad52:3201:214:fdff:fe10:4f86]:58110) by pandora.armlinux.org.uk with esmtpsa (TLSv1.2:AES128-GCM-SHA256:128) (Exim 4.82_1-5b7a7c0-XX) (envelope-from ) id 1f1JKe-00047U-9W; Wed, 28 Mar 2018 23:14:12 +0100 Received: from linux by n2100.armlinux.org.uk with local (Exim 4.82_1-5b7a7c0-XX) (envelope-from ) id 1f1JKW-0004AT-2Q; Wed, 28 Mar 2018 23:14:04 +0100 Date: Wed, 28 Mar 2018 23:14:01 +0100 From: Russell King - ARM Linux To: Rob Landley Cc: 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 , Oliver O'Halloran , 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@lists.ozlabs.org, 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 Subject: Re: [PATCH] Extract initrd free logic from arch-specific code. Message-ID: <20180328221401.GA14084@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> 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: 63321 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 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 ?) -- 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: Wed, 28 Mar 2018 23:14:01 +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> Message-ID: <20180328221401.GA14084@n2100.armlinux.org.uk> To: linux-riscv@lists.infradead.org List-Id: linux-riscv.lists.infradead.org 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 ?) -- 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: Wed, 28 Mar 2018 23:14:01 +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> List-ID: Message-ID: <20180328221401.GA14084@n2100.armlinux.org.uk> To: linux-snps-arc@lists.infradead.org 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 ?) -- 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: Wed, 28 Mar 2018 23:14:01 +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> Message-ID: <20180328221401.GA14084@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 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 ?) -- 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