On 12.02.2013, at 03:00, David Gibson wrote: > The target-ppc code supports CPUs with a number of different MMU > types: there's both the 32-bit and 64-bit versions of the "classic" > hash page table based powerpc mmu and there's also the BookE and 40x > MMUs. > > Currently handling of all these has a roughly shared path in > mmu_helper.c. Although code sharing is usually a good idea, in this > case the MMUs really aren't similar enough for this to be useful. > Instead it results in checking and behaving differently at many, many > different points in the path leading to an unreadable tangle of code. > > This patch series is a first step to cleaning this up, moving to a > model where we have a single switch on the MMU family at the top-level > entry points, then have a simpler, clearer separate code path for each > MMU type. More specifically, it disentangles the path for the 64-bit > classic hash MMU into its own new file. The other MMU types keep the > existing code (minus 64-bit hash specific conditionals) for now. > Disentangling those as well would be a good idea, but would be best > done by someone with more resources to test those other platforms than > I have. > > For now, the resulting 64-bit hash path retains the same structure as > the original shared code, just the obvious conditionals on other mmu > types are removed. This path is fairly ugly in itself, but cleaning > that up is a later step, now much simpler without the other MMU types > to deal with at the same time.
Looks like a nice and long overdue cleanup. A few points I'd like to see addressed: - Instead of exporting common helper functions, put them into a new mmu-hash.h as static inline. That way things can get optimized a lot better. - Please extract the 32bit hash functions into a separate file as well. You're touching all that code anyways, so I'm sure you can test it :). - QOM'ify things please :). Just make your mmu type specific function calls function pointers in the class and invoke them from there instead of the switchery. Alex
