On Mon, 2011-04-18 at 17:30 -0500, Kumar Gala wrote: > > On Mon, 2011-04-18 at 07:42 -0500, Kumar Gala wrote: > >> Let's rename this function to something 'linear_map'. As on FSL > >> Book-E 64 we do things a bit differently and have more covered in > >> linear map than 1G > > > > It's not quite linear_map. It's whatever can be accessed without > taking > > exceptions. IE. What is bolted. > > > > It should probably go into a variable initialized by the mm code > tho. > > > > Cheers, > > Ben. > > Is this 'ppc64_rma_size' ?
Not quite either :-) The RMA (on server) is the amount of memory that is accessible in real mode (with MMU off). SLB0 is segment 0, which is 256M or 1T depending on what segment size we use, and is a bolted segment in Linux. Thus all accesses to SLB0 are guaranteed to not generate an SLB miss fault. Since on server our linear mapping is bolted in the hash, what that means is that any access to memory in segment 0 is guaranteed to not take an exception (ie not clobber SRR0/1 for example). We re-use the SLB0 concept on BookE to represent the bolted portion of the linear mapping since it has the same characteristics, ie, accesses will not cause an exception that can clobber SRR0/1. The patch Michael posted is indeed a bit gross (it's my code btw :-) and we'll need to clean it up, my idea is to have a global set by the platform, but maybe we can have some generic code that performs a TLB search for IPROT entries :-) Cheers, Ben. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
