+CC Thomas, Peter On Friday 15 January 2016 04:19 PM, Alexey Brodkin wrote: > Hi Felix, > > On Fri, 2016-01-15 at 11:45 +0100, Felix Fietkau wrote: >> On 2016-01-15 00:12, Alexey Brodkin wrote: >>> Given those patches are relevant to any ARC platform and even >>> ISA version it makes perfect sense for patches to exist >>> in one place instead of being duplicated for each new ARC-based ASIC. >>> >>> Note this is a prerequisite for upstreaming of ARC HS38 support in >>> OpenWRT. >>> >>> Signed-off-by: Alexey Brodkin <abrodkin at synopsys.com> >>> Cc: Felix Fietkau <nbd at openwrt.org> >>> Cc: Jo-Philipp Wich <jow at openwrt.org> >>> Cc: Jonas Gorski <jogo at openwrt.org> >>> --- /dev/null >>> +++ b/target/linux/generic/patches-4.4/331-arc-remove-dependency-on-DEVTMPFS.patch >>> @@ -0,0 +1,36 @@ >>> +From adfbf9e6cad93281cffceab078e7f6f2a8e094f9 Mon Sep 17 00:00:00 2001 >>> +From: Alexey Brodkin <abrodkin at synopsys.com> >>> +Date: Thu, 13 Aug 2015 01:56:02 +0300 >>> +Subject: [PATCH 1/2] openwrt: arc - remove dependency on DEVTMPFS >>> + >>> +OpenWRT builds initramfs so that it doesn't require DEVTMPFS so dropping >>> +this dependency. Really ? AFAIKR (circa 2012) DEVTMPFS was *needed* for dynamic device nodes and that included the common case of initramfs NOT having static device nodes. So back then I added the code in question to kernel Kconfig because initramfs was my primary workflow and occassionally I would fail to include DEVTMPFS causing userspace boot to go bonkers (FWIW I was using the buildroot trick of a pre-init script which would automount devtmpfs before exec'ing the real init) Now arguably I can add DEVTMPFS to defconfigs, but then we don't need the kconfig dependency framework at all. Another idea is to add DEVTMPFS unconditionally to Kconfig, but I fail to remember why I didn't do it at the time. Does anyone know if it interferes with real rootfs backed by real devices ? >>> That helps to escape 2 separate kernel rebuilds with >>> +and without initramfs. >>> + >>> +2 builds happen because OpenWRT first builds kernel and later modules. >>> +When building entire kernel with simple "make" INITRAMFS sets to a real >>> +value and so was triggering DEVTMPFS selection. Then when building only >>> +modules with "make modules" command INITRAMFS is zeroed and so kernel >>> +config was changing that lead to full kernel rebuild. Just curious, why does make module zero out INITRAMFS - to save a bit of build time ? -Vineet >>> + >>> +Signed-off-by: Alexey Brodkin <abrodkin at synopsys.com> >>> +--- >>> + arch/arc/Kconfig | 2 -- >>> + 1 file changed, 2 deletions(-) >>> + >>> +diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig >>> +index 6312f60..a95bab3 100644 >>> +--- a/arch/arc/Kconfig >>> ++++ b/arch/arc/Kconfig >>> +@@ -12,8 +12,6 @@ config ARC >>> + select BUILDTIME_EXTABLE_SORT >>> + select COMMON_CLK >>> + select CLONE_BACKWARDS >>> +- # ARC Busybox based initramfs absolutely relies on DEVTMPFS for /dev >>> +- select DEVTMPFS if !INITRAMFS_SOURCE="" >>> + select GENERIC_ATOMIC64 >>> + select GENERIC_CLOCKEVENTS >>> + select GENERIC_FIND_FIRST_BIT >> Could you please send this one upstream as well? > Adding Vineet so he may comment if that change makes sense upstream. > > -Alexey
