On Wed, 15 Jun 2011 20:11:55 +1000 Benjamin Herrenschmidt <b...@kernel.crashing.org> wrote:
> On Wed, 2011-06-15 at 11:43 +0530, Suzuki Poulose wrote: > > On 06/14/11 17:34, Michal Simek wrote: > > > Hi, > > > > > > have someone tried to support RELOCATABLE kernel on ppc44x? > > As Josh, mentioned, I will be working on this. In fact I was trying a > > couple of > > patches towards this on PPC440x. But, I am stuck in debugging the hang that > > I am > > experiencing with the changes. I am setting up a RISCWatch processor probe > > to > > debug the same. > > > > Here is some information that I wanted to share : > > > > The PPC440X currently uses 256M TLB entries to pin the lowmem. When we go > > for a > > relocatable kernel we have to : > > > > 1) Restrict the kernel load address to be 256M aligned > > Wait a minute ... :-) > > There's a difference between having the kernel run from any address and > mapping the linear mapping not starting at 0. > > Those are completely orthogonal. > > I don't see why off hand you are changing the way the TLB is used. The > only possible change needed is to make sure the initial bolted entry set > by the asm code properly covers the kernel in whatever it's "current" > location is. The rest is a matter of fixing up the relocations... Changing where the linear mapping points to is useful for AMP configurations where you're supposed to be considering your memory to be a subset of the real memory. This is implemented on e500 as CONFIG_RELOCATABLE, though it should have been called something different since it's not really building a relocatable kernel (unlike what 64-bit does with CONFIG_RELOCATABLE). -Scott _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev