On Sun, Jun 11, 2023 at 9:34 AM Marek Vasut <marek.vasut@xxxxxxxxxxx> wrote: > > On 6/9/23 15:48, Adam Ford wrote: > > I was wondering if anyone has ever attempted to build a 32-bit kernel > > to run on an RZ/G2 or RCAR3 SoC. > > Not me > > > I have a variant with than 2GB of RAM, and I want to run some > > experiments to measure RAM utilization and performance to see if it's > > worth trying to run in 32-bit mode to save a little RAM. > > It might be worth looking at arm64 ilp32 too, that retains you the > armv8a instructions, i.e. you get the 32bit pointers without the armv7a > opcodes downsides. > > > It looks like U-Boot supports AARCH32, but most of the stuff I can > > find when searching has people building applications in 32-bit space > > running on a 64-bit kernel, but I am hoping to try everything in > > 32-bit mode. I have build the multi_v7 kernel with an ARMv7 compiler, > > but attempts to boot that kernel cause a crash. I am guessing I need > > to enable some additional flag somewhere, or somehow tell U-Boot it's > > a 32-bit kernel. > > Maybe look at what RPi does, I think they run 32bit OR 64bit kernel on > RPi3 built from the same source and using the same DT . Thanks for the tip! I'll check that out. adam
