Schism: Splitting RV32 from `arch/riscv` - - We Could Both... "Ruinland"
summary
Proposal splits arch/riscv32 and arch/riscv64 so 32-bit RISC‑V can carry different code, backed by a minimal RV32 profile ("B" profile) that drops the A (atomic) requirement, restores HIGHMEM for 2–4+ GB boards, and keeps kernel-provided user helpers (kuser-style) plus libgcc intrinsics (libgcc/atomic.c, libconfig) to emulate atomics on no‑MMU devices. Proof‑of‑concept is copy‑paste plus Makefile fixes; patches are being cleaned for upstreaming; vendors with HPMicro/Allwinner silicon intend to maintain the new arch but maintenance and ABI sync remain open.
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chapters (8)
- 0:00Introduction to schism
- 1:27Why split RV32 from arch/riscv
- 4:18Proposed RV32 profile details
- 7:57Maintenance and responsibility plans
- 15:21Motivation for code separation
- 18:54Community feedback and concerns
- 25:41Future synchronization challenges
- 28:09Q&A and closing remarks
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