From: Palmer Dabbelt <palmer@xxxxxxxxxxxx> We're stuck supporting scalar misaligned loads in userspace because they were part of the ISA at the time we froze the uABI. That wasn't the case for vector misaligned accesses, so depending on them unconditionally is a userspace bug. All extant vector hardware traps on these misaligned accesses. Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx> --- Documentation/arch/riscv/uabi.rst | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/Documentation/arch/riscv/uabi.rst b/Documentation/arch/riscv/uabi.rst index 54d199dce78b..2b420bab0527 100644 --- a/Documentation/arch/riscv/uabi.rst +++ b/Documentation/arch/riscv/uabi.rst @@ -65,4 +65,6 @@ the extension, or may have deliberately removed it from the listing. Misaligned accesses ------------------- -Misaligned accesses are supported in userspace, but they may perform poorly. +Misaligned scalar accesses are supported in userspace, but they may perform +poorly. Misaligned vector accesses are only supported if the Zicclsm extension +is supported. -- 2.45.0
