On Wed, Jul 20, 2022 at 09:50:10PM +0100, Mark Brown wrote: > Currently our SVE syscall ABI documentation does not reflect the actual > implemented ABI, it says that register state not shared with FPSIMD > becomes undefined on syscall when in reality we always clear it. Since > changing this would cause a change in the observed kernel behaviour > there is a substantial desire to avoid taking advantage of the > documented ABI so instead let's document what we actually do so it's > clear that it is in reality an ABI. > > There has been some pushback on tightening the documentation in the past > but it is hard to see who that helps, it makes the implementation > decisions less clear and makes it harder for people to discover and make > use of the actual ABI. The main practical concern is that qemu's user > mode does not currently flush the registers. > > Mark Brown (3): > kselftest/arm64: Correct buffer allocation for SVE Z registers > arm64/sve: Document our actual ABI for clearing registers on syscall > kselftest/arm64: Enforce actual ABI for SVE syscalls For the series: Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
