On Mon, Mar 29, 2021 at 08:01:41PM +0800, Guo Ren wrote: > u32 a = 0x55aa66bb; > u16 *ptr = &a; > > CPU0 CPU1 > ========= ========= > xchg16(ptr, new) while(1) > WRITE_ONCE(*(ptr + 1), x); > > When we use lr.w/sc.w implement xchg16, it'll cause CPU0 deadlock. Then I think your LL/SC is broken. That also means you really don't want to build super complex locking primitives on top, because that live-lock will percolate through. Step 1 would be to get your architecute fixed such that it can provide fwd progress guarantees for LL/SC. Otherwise there's absolutely no point in building complex systems with it.
