On Wed, 2009-08-05 at 18:47 -0500, Scott Wood wrote: > On Thu, Aug 06, 2009 at 12:49:45AM +0200, Kenneth Johansson wrote: > > On Wed, 2009-08-05 at 01:06 +0200, Sebastian Andrzej Siewior wrote: > > > I've tried kexec on e300 core which should be easy since it is possible > > > to disable the MMU on that core. However it does not work. > > > > Is it not possible to disable the mmu on all cpu's that have one ?? > > No, on e500 for example it is always on. You can use large pages with > identity maps to make it seem like it's off, though.
why do something like that ? > > Before you turn off the cache you need to flush out all dirty data. best > > done by simply reading in 32kb of crap from somewhere. otherwise you are > > sure to loose at least the stack and you do not want that. > > 32KiB is usually not sufficient -- depending on the initial state, an > 8-way 32KiB cache with PLRU (such as in e300) can require up to 52KiB of > data (13 loads per set) to fully flush if you simply load+dcbf (in > separate passes) an arbitrary chunk of data which may already be in the > cache. if you have int crap[1024*32/4] __attribute__((aligned(32))) What will happen with the cache if you just load data into a register from that array ?? Wont it force out everything else in the cache to make room for the crap ? _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
