From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [PATCH v2 0/2] arm64: Cut rebuild time when changing CONFIG_BLK_DEV_INITRD Date: Thu, 25 Oct 2018 08:15:15 -0500 Message-ID: References: <20181024193256.23734-1-f.fainelli@gmail.com> <20181025093833.GA23607@rapoport-lnx> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: In-Reply-To: <20181025093833.GA23607@rapoport-lnx> Sender: linux-kernel-owner@vger.kernel.org To: rppt@linux.ibm.com, Ard Biesheuvel Cc: Florian Fainelli , "linux-kernel@vger.kernel.org" , Catalin Marinas , Will Deacon , Arnd Bergmann , Greg Kroah-Hartman , Marc Zyngier , Olof Johansson , linux-alpha@vger.kernel.org, arcml , "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" , linux-c6x-dev@linux-c6x.org, "moderated list:H8/300 ARCHITECTURE" , linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, Linux-MIPS , nios2-dev@lists. List-Id: linux-arch.vger.kernel.org +Ard On Thu, Oct 25, 2018 at 4:38 AM Mike Rapoport wrote: > > On Wed, Oct 24, 2018 at 02:55:17PM -0500, Rob Herring wrote: > > On Wed, Oct 24, 2018 at 2:33 PM Florian Fainelli wrote: > > > > > > Hi all, > > > > > > While investigating why ARM64 required a ton of objects to be rebuilt > > > when toggling CONFIG_DEV_BLK_INITRD, it became clear that this was > > > because we define __early_init_dt_declare_initrd() differently and we do > > > that in arch/arm64/include/asm/memory.h which gets included by a fair > > > amount of other header files, and translation units as well. > > > > I scratch my head sometimes as to why some config options rebuild so > > much stuff. One down, ? to go. :) > > > > > Changing the value of CONFIG_DEV_BLK_INITRD is a common thing with build > > > systems that generate two kernels: one with the initramfs and one > > > without. buildroot is one of these build systems, OpenWrt is also > > > another one that does this. > > > > > > This patch series proposes adding an empty initrd.h to satisfy the need > > > for drivers/of/fdt.c to unconditionally include that file, and moves the > > > custom __early_init_dt_declare_initrd() definition away from > > > asm/memory.h > > > > > > This cuts the number of objects rebuilds from 1920 down to 26, so a > > > factor 73 approximately. > > > > > > Apologies for the long CC list, please let me know how you would go > > > about merging that and if another approach would be preferable, e.g: > > > introducing a CONFIG_ARCH_INITRD_BELOW_START_OK Kconfig option or > > > something like that. > > > > There may be a better way as of 4.20 because bootmem is now gone and > > only memblock is used. This should unify what each arch needs to do > > with initrd early. We need the physical address early for memblock > > reserving. Then later on we need the virtual address to access the > > initrd. Perhaps we should just change initrd_start and initrd_end to > > physical addresses (or add 2 new variables would be less invasive and > > allow for different translation than __va()). The sanity checks and > > memblock reserve could also perhaps be moved to a common location. > > > > Alternatively, given arm64 is the only oddball, I'd be fine with an > > "if (IS_ENABLED(CONFIG_ARM64))" condition in the default > > __early_init_dt_declare_initrd as long as we have a path to removing > > it like the above option. > > I think arm64 does not have to redefine __early_init_dt_declare_initrd(). > Something like this might be just all we need (completely untested, > probably it won't even compile): > > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > index 9d9582c..e9ca238 100644 > --- a/arch/arm64/mm/init.c > +++ b/arch/arm64/mm/init.c > @@ -62,6 +62,9 @@ s64 memstart_addr __ro_after_init = -1; > phys_addr_t arm64_dma_phys_limit __ro_after_init; > > #ifdef CONFIG_BLK_DEV_INITRD > + > +static phys_addr_t initrd_start_phys, initrd_end_phys; > + > static int __init early_initrd(char *p) > { > unsigned long start, size; > @@ -71,8 +74,8 @@ static int __init early_initrd(char *p) > if (*endp == ',') { > size = memparse(endp + 1, NULL); > > - initrd_start = start; > - initrd_end = start + size; > + initrd_start_phys = start; > + initrd_end_phys = end; > } > return 0; > } > @@ -407,14 +410,27 @@ void __init arm64_memblock_init(void) > memblock_add(__pa_symbol(_text), (u64)(_end - _text)); > } > > - if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && initrd_start) { > + if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && > + (initrd_start || initrd_start_phys)) { > + /* > + * FIXME: ensure proper precendence between > + * early_initrd and DT when both are present Command line takes precedence, so just reverse the order. > + */ > + if (initrd_start) { > + initrd_start_phys = __phys_to_virt(initrd_start); > + initrd_end_phys = __phys_to_virt(initrd_end); AIUI, the original issue was doing the P2V translation was happening too early and the VA could be wrong if the linear range is adjusted. So I don't think this would work. I suppose you could convert the VA back to a PA before any adjustments and then back to a VA again after. But that's kind of hacky. 2 wrongs making a right. > + } else if (initrd_start_phys) { > + initrd_start = __va(initrd_start_phys); > + initrd_end = __va(initrd_start_phys); > + } > + > /* > * Add back the memory we just removed if it results in the > * initrd to become inaccessible via the linear mapping. > * Otherwise, this is a no-op > */ > - u64 base = initrd_start & PAGE_MASK; > - u64 size = PAGE_ALIGN(initrd_end) - base; > + u64 base = initrd_start_phys & PAGE_MASK; > + u64 size = PAGE_ALIGN(initrd_end_phys) - base; > > /* > * We can only add back the initrd memory if we don't end up > @@ -458,7 +474,7 @@ void __init arm64_memblock_init(void) > * pagetables with memblock. > */ > memblock_reserve(__pa_symbol(_text), _end - _text); > -#ifdef CONFIG_BLK_DEV_INITRD > +#if 0 > if (initrd_start) { > memblock_reserve(initrd_start, initrd_end - initrd_start); > > > > Rob > > > > -- > Sincerely yours, > Mike. > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:55122 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727365AbeJYVsL (ORCPT ); Thu, 25 Oct 2018 17:48:11 -0400 MIME-Version: 1.0 References: <20181024193256.23734-1-f.fainelli@gmail.com> <20181025093833.GA23607@rapoport-lnx> In-Reply-To: <20181025093833.GA23607@rapoport-lnx> From: Rob Herring Date: Thu, 25 Oct 2018 08:15:15 -0500 Message-ID: Subject: Re: [PATCH v2 0/2] arm64: Cut rebuild time when changing CONFIG_BLK_DEV_INITRD Content-Type: text/plain; charset="UTF-8" Sender: linux-arch-owner@vger.kernel.org List-ID: To: rppt@linux.ibm.com, Ard Biesheuvel Cc: Florian Fainelli , "linux-kernel@vger.kernel.org" , Catalin Marinas , Will Deacon , Arnd Bergmann , Greg Kroah-Hartman , Marc Zyngier , Olof Johansson , linux-alpha@vger.kernel.org, arcml , "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" , linux-c6x-dev@linux-c6x.org, "moderated list:H8/300 ARCHITECTURE" , linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, Linux-MIPS , nios2-dev@lists.rocketboards.org, Openrisc , linux-parisc@vger.kernel.org, linuxppc-dev , linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, SH-Linux , sparclinux@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, devicetree@vger.kernel.org, "open list:GENERIC INCLUDE/ASM HEADER FILES" Message-ID: <20181025131515.F9n5Yz7Vg6iiKsxq6ROduS_LqWtpDM0wtqFwOpxDl_4@z> +Ard On Thu, Oct 25, 2018 at 4:38 AM Mike Rapoport wrote: > > On Wed, Oct 24, 2018 at 02:55:17PM -0500, Rob Herring wrote: > > On Wed, Oct 24, 2018 at 2:33 PM Florian Fainelli wrote: > > > > > > Hi all, > > > > > > While investigating why ARM64 required a ton of objects to be rebuilt > > > when toggling CONFIG_DEV_BLK_INITRD, it became clear that this was > > > because we define __early_init_dt_declare_initrd() differently and we do > > > that in arch/arm64/include/asm/memory.h which gets included by a fair > > > amount of other header files, and translation units as well. > > > > I scratch my head sometimes as to why some config options rebuild so > > much stuff. One down, ? to go. :) > > > > > Changing the value of CONFIG_DEV_BLK_INITRD is a common thing with build > > > systems that generate two kernels: one with the initramfs and one > > > without. buildroot is one of these build systems, OpenWrt is also > > > another one that does this. > > > > > > This patch series proposes adding an empty initrd.h to satisfy the need > > > for drivers/of/fdt.c to unconditionally include that file, and moves the > > > custom __early_init_dt_declare_initrd() definition away from > > > asm/memory.h > > > > > > This cuts the number of objects rebuilds from 1920 down to 26, so a > > > factor 73 approximately. > > > > > > Apologies for the long CC list, please let me know how you would go > > > about merging that and if another approach would be preferable, e.g: > > > introducing a CONFIG_ARCH_INITRD_BELOW_START_OK Kconfig option or > > > something like that. > > > > There may be a better way as of 4.20 because bootmem is now gone and > > only memblock is used. This should unify what each arch needs to do > > with initrd early. We need the physical address early for memblock > > reserving. Then later on we need the virtual address to access the > > initrd. Perhaps we should just change initrd_start and initrd_end to > > physical addresses (or add 2 new variables would be less invasive and > > allow for different translation than __va()). The sanity checks and > > memblock reserve could also perhaps be moved to a common location. > > > > Alternatively, given arm64 is the only oddball, I'd be fine with an > > "if (IS_ENABLED(CONFIG_ARM64))" condition in the default > > __early_init_dt_declare_initrd as long as we have a path to removing > > it like the above option. > > I think arm64 does not have to redefine __early_init_dt_declare_initrd(). > Something like this might be just all we need (completely untested, > probably it won't even compile): > > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > index 9d9582c..e9ca238 100644 > --- a/arch/arm64/mm/init.c > +++ b/arch/arm64/mm/init.c > @@ -62,6 +62,9 @@ s64 memstart_addr __ro_after_init = -1; > phys_addr_t arm64_dma_phys_limit __ro_after_init; > > #ifdef CONFIG_BLK_DEV_INITRD > + > +static phys_addr_t initrd_start_phys, initrd_end_phys; > + > static int __init early_initrd(char *p) > { > unsigned long start, size; > @@ -71,8 +74,8 @@ static int __init early_initrd(char *p) > if (*endp == ',') { > size = memparse(endp + 1, NULL); > > - initrd_start = start; > - initrd_end = start + size; > + initrd_start_phys = start; > + initrd_end_phys = end; > } > return 0; > } > @@ -407,14 +410,27 @@ void __init arm64_memblock_init(void) > memblock_add(__pa_symbol(_text), (u64)(_end - _text)); > } > > - if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && initrd_start) { > + if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && > + (initrd_start || initrd_start_phys)) { > + /* > + * FIXME: ensure proper precendence between > + * early_initrd and DT when both are present Command line takes precedence, so just reverse the order. > + */ > + if (initrd_start) { > + initrd_start_phys = __phys_to_virt(initrd_start); > + initrd_end_phys = __phys_to_virt(initrd_end); AIUI, the original issue was doing the P2V translation was happening too early and the VA could be wrong if the linear range is adjusted. So I don't think this would work. I suppose you could convert the VA back to a PA before any adjustments and then back to a VA again after. But that's kind of hacky. 2 wrongs making a right. > + } else if (initrd_start_phys) { > + initrd_start = __va(initrd_start_phys); > + initrd_end = __va(initrd_start_phys); > + } > + > /* > * Add back the memory we just removed if it results in the > * initrd to become inaccessible via the linear mapping. > * Otherwise, this is a no-op > */ > - u64 base = initrd_start & PAGE_MASK; > - u64 size = PAGE_ALIGN(initrd_end) - base; > + u64 base = initrd_start_phys & PAGE_MASK; > + u64 size = PAGE_ALIGN(initrd_end_phys) - base; > > /* > * We can only add back the initrd memory if we don't end up > @@ -458,7 +474,7 @@ void __init arm64_memblock_init(void) > * pagetables with memblock. > */ > memblock_reserve(__pa_symbol(_text), _end - _text); > -#ifdef CONFIG_BLK_DEV_INITRD > +#if 0 > if (initrd_start) { > memblock_reserve(initrd_start, initrd_end - initrd_start); > > > > Rob > > > > -- > Sincerely yours, > Mike. >