On Fri, 27 Mar 2026 at 20:25, Oliver Smith-Denny via groups.io
<[email protected]> wrote:
>
> Hi AARCH64 maintainers,
>
> As I am reviewing https://github.com/tianocore/edk2/pull/12340
> and considering some of the efforts we've had to remove
> code from ArmPkg and ArmPlatformPkg
> (https://github.com/tianocore/edk2/issues/10289), I'm wondering
> if ArmLib should be largely (or completely) merged into BaseLib.
>
> Obviously, in most efforts moving code out of ArmPkg, we run
> into the ArmLib dependency and either need to add ArmPkg as
> a dependency of whatever package or give up on moving the code.
>
> ArmLib, as far as I can tell, was originally designed to be
> BaseLib for AARCH64 (its inf is even called ArmBaseLib.inf).
TBH, I think the name is more because of
MODULE_TYPE = BASE
> I haven't looked at each interface there, but the majority are
> interacting with registers, which is what other architectures
> use BaseLib for. E.g. ArmWriteVbar() is in ArmLib, x86's
> AsmWriteIdtr() is in BaseLib. I believe most of the functions
> would fall into this category of matching other architectures
> existing definitions in BaseLib.
>
> The definitions there may belong better in MdePkg/Include/AArch64;
> I need to look a little closer at those, but the page table defs
> for instance are there for x86.
>
> ArmLib only has a dependency on DebugLib and a quick test removing
> that dependency shows it isn't actually using it, which makes sense
> for inclusion in BaseLib.
>
> This does make BaseLib larger, of course, but also removes a special
> interface for AARCH64 only that all other architectures use BaseLib
> for.
>
> Thoughts?
I think here be dragons, but I fully agree with your ultimate goal.
I have a feeling non-x86 architectures will have more knobs to deal with,
resulting in the larger size as you identify. Ultimately I wonder if that means
some/much of what is in ArmLib today would better belong somewhere in
UefiCpuPkg than being included for ... effectively every single app or
driver. This might mean for consistency certain functions currently in
BaseLib for other architectures should also move.
But also, since we support LTO pretty much everywhere now, maybe much
of the bloat just gets eliminated?
> If we agree on this general path, I will take up the work to merge
> ArmLib into BaseLib (where appropriate). I will need to evaluate
> each function closer, but again, a quick review seems like most would
> be appropriate in BaseLib.
I vote yes.
Thanks!
/
Leif
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