been a couple of months, but finally got around to reporting that rust doesnt work on armv7 if u only specify LLVM=1 on Linux. if u specify LLVM=1 and CC+=gcc, only then it will work
figured this out ~1 month ago because adrianyyy@chaos.social fixed linux-next to only use LLVM (whereas before it was using LLVM and gcc). this seemed to break my setup, and confirmed what was happening when i was externally building the kernel
https://gitlab.postmarketos.org/postmarketOS/pmbootstrap/-/issues/2635#note_520266