On Thu, 10 Feb 2022, Casey Bowman <casey.g.bowman@xxxxxxxxx> wrote: > In this RFC I would like to ask the community their thoughts > on how we can best handle splitting architecture-specific > calls. > > I would like to address the following: > > 1. How do we want to split architecture calls? Different object files > per platform? Separate function calls within the same object file? > > 2. How do we address dummy functions? If we have a function call that is > used for one or more platforms, but is not used in another, what should > we do for this case? > > I've given an example of splitting an architecture call > in my patch with run_as_guest() being split into different > implementations for x86 and arm64 in separate object files, sharing > a single header. > > Another suggestion from Michael (michael.cheng@xxxxxxxxx) involved > using a single object file, a single header, and splitting various > functions calls via ifdefs in the header file. > > I would appreciate any input on how we can avoid scaling issues when > including multiple architectures and multiple functions (as the number > of function calls will inevitably increase with more architectures). > > v2: Revised to use kernel's platform-splitting scheme. I think this is overengineering. Just add different implementations of the functions per architecture next to where they are now, like I suggested before. If we need to split them better later, it'll be a trivial undertaking, and we'll be in a better position to do it because we'll know how many functions there'll be and where they are and what they do. Adding a bunch of overhead from the start seems like the wrong thing to do. BR, Jani. > > Casey Bowman (1): > i915/drm: Split out x86 and arm64 functionality > > drivers/gpu/drm/i915/Makefile | 3 +++ > drivers/gpu/drm/i915/i915_drv.h | 7 ++----- > drivers/gpu/drm/i915/platforms/Makefile | 8 ++++++++ > .../arm64/include/platform/i915_hypervisor.h | 11 +++++++++++ > .../platforms/x86/include/platform/i915_hypervisor.h | 9 +++++++++ > 5 files changed, 33 insertions(+), 5 deletions(-) > create mode 100644 drivers/gpu/drm/i915/platforms/Makefile > create mode 100644 drivers/gpu/drm/i915/platforms/arm64/include/platform/i915_hypervisor.h > create mode 100644 drivers/gpu/drm/i915/platforms/x86/include/platform/i915_hypervisor.h -- Jani Nikula, Intel Open Source Graphics Center
