On Wed, Aug 04, 2004 at 12:36:56PM -0400, Dan Malek wrote: > > On Aug 4, 2004, at 7:49 AM, Josh Boyer wrote: > > > Maybe pinning a read-only TLB entry for most of the text pages for > > however large you can get would work... or maybe not. > > The problem is BATs and pinned TLBs require alignment restrictions > that don't allow this. > > > .....But when someone is writing new drivers, randomly poking > > holes in the kernel text pages and then executing instructions from > > there leads to some strange panics. Although, the new driver should be > > suspect in that case anyway :). > > Then, on MPC8xx don't select pinned TLBs to cover the kernel > space, and on traditional PPC MMUs select the 'nobat' option > on the command line. This will write protect the kernel text pages. > However, if you select something like CONFIG_KGDB, this will > allow writing of the text pages to set breakpoints. You will need > to use a debugger like the BDI2000 and use hardware breakpoints > to do your debugging. When you are done, you can enable the > performance TLB options again. I thought the 4xx allowed > something like this as well. If not, it could and probably should.
We eagerly await your patch. ;) -Matt ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
