Aaron Durbin has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/37368 )
Change subject: arch/x86/car: Remove runtime stack alignment enforcing ......................................................................
Patch Set 2: Code-Review-1
Patch Set 2: Code-Review-2
These sequences are for ensuring the compiler's ABI is met when getting into C code. The expectation is that the stack is aligned to 16-byte boundary at the time of the call.
I see this alignment was directly after using _ecar_stack symbol and reliant upon the previous patch. I'm not sure we gain much but saving a few bytes of instruction with the linker assertion. To me it reads better keeping the code there. If you really want to keep save an instruction please annotate the usage of _ecar_stack with a comment indicating you are reliant upon that symbol being 16-byte aligned. As the patch currently stands we've lost all knowledge of the assumptions and intention.