On Thu, Feb 04, 2021 at 03:41:59PM -0800, Yu, Yu-cheng wrote: > On 2/4/2021 12:35 PM, Kees Cook wrote: > > On Wed, Feb 03, 2021 at 02:55:46PM -0800, Yu-cheng Yu wrote: > > > arch_prctl(ARCH_X86_CET_STATUS, u64 *args) > > > Get CET feature status. > > > > > > The parameter 'args' is a pointer to a user buffer. The kernel returns > > > the following information: > > > > > > *args = shadow stack/IBT status > > > *(args + 1) = shadow stack base address > > > *(args + 2) = shadow stack size > > > > What happens if this needs to grow in the future? Should the first u64 > > contain the array size? > > > > Otherwise, looks sensible. > > > > -Kees > > > > The first item is a bitmap, and there are two possible bits. Should there > be a need, we can then do things about it. My thought at the moment is, we > may not meet the situation. Can we keep this for now? Ah, good point. Yes, since that's a bitmap it ends up describing what follows. This is fine as-is. Thanks! Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> -- Kees Cook
