From af042c457db07db4bc1baa5c22d089cab69cfc5b Mon Sep 17 00:00:00 2001 From: Alexandre Ghiti Date: Sun, 3 Nov 2024 15:51:42 +0100 Subject: [PATCH] riscv: Do not fail to build on byte/halfword operations with Zawrs riscv does not have lr instructions on byte and halfword but the qspinlock implementation actually uses such atomics provided by the Zabha extension, so those sizes are legitimate. Then instead of failing to build, just fallback to the !Zawrs path. Signed-off-by: Alexandre Ghiti Reviewed-by: Andrew Jones Reviewed-by: Andrea Parri Link: https://lore.kernel.org/r/20241103145153.105097-3-alexghiti@rivosinc.com Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/cmpxchg.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/riscv/include/asm/cmpxchg.h b/arch/riscv/include/asm/cmpxchg.h index ebbce134917cc..ac1d7df898ef4 100644 --- a/arch/riscv/include/asm/cmpxchg.h +++ b/arch/riscv/include/asm/cmpxchg.h @@ -245,6 +245,11 @@ static __always_inline void __cmpwait(volatile void *ptr, : : : : no_zawrs); switch (size) { + case 1: + fallthrough; + case 2: + /* RISC-V doesn't have lr instructions on byte and half-word. */ + goto no_zawrs; case 4: asm volatile( " lr.w %0, %1\n"