Re: git: a60e7e6ff0ec - main - stand: compile ia32 EFI loader with -malign-double
Date: Sun, 15 Feb 2026 14:27:42 UTC
On Sun Feb 15, 2026 at 4:02 PM +0200, Jessica Clarke wrote: > On 15 Feb 2026, at 13:56, Ahmad Khalifa <vexeduxr@FreeBSD.org> wrote: >> >> The branch main has been updated by vexeduxr: >> >> URL: https://cgit.FreeBSD.org/src/commit/?id=a60e7e6ff0ec1fdd66c2568ac6c03b843dbb3c9d >> >> commit a60e7e6ff0ec1fdd66c2568ac6c03b843dbb3c9d >> Author: Ahmad Khalifa <vexeduxr@FreeBSD.org> >> AuthorDate: 2026-02-15 12:23:26 +0000 >> Commit: Ahmad Khalifa <vexeduxr@FreeBSD.org> >> CommitDate: 2026-02-15 13:30:06 +0000 >> >> stand: compile ia32 EFI loader with -malign-double >> >> The UEFI spec says: >>> Structures are aligned on boundaries equal to the largest internal >>> datum of the structure and internal data are implicitly padded to >>> achieve natural alignment. >> >> By default, structs containing members of type "long long" have 4 byte >> alignment on i386. This caused some EFI structures to be subtly wrong. >> >> Fix this by compiling the ia32 EFI loader with -malign-double, which >> bumps the alignment up to 8 if such members are present. > > This seems like a dangerously big hammer. Are there any types shared > with libsa or the kernel itself that would change layout? (I suppose > for the latter they already need to be aligned as the kernel is 64-bit?) For the kernel, any shared types would have already needed to be aligned, yes. I didn't consider shared types with either libsa or libefi though, I'll look into it now. Nice catch. > > Annotating just the EFI types would seem more appropriate, like how we > annotate function pointers to use the Microsoft calling convention. They're all under contrib unfortunately. Not sure if we want to introduce that big of a diff with upstream. > > Jessica