On Mon, 2022-10-10 at 12:56 +0200, Florian Weimer wrote: > > + /* Only support enabling/disabling one feature at a time. */ > > + if (hweight_long(features) > 1) > > + return -EINVAL; > > This means we'll soon need three extra system calls for x86-64 > process > start: SHSTK, IBT, and switching off vsyscall emulation. (The latter > does not need any special CPU support.) > > Maybe we can do something else instead to make the strace output a > little bit cleaner? In previous versions it supported enabling multiple features in a single syscall. Thomas Gleixner pointed out that (this was on the LAM patchset that shared the interface at the time) it makes the behavior of what to do when one feature fails to enable complicated: https://lore.kernel.org/lkml/87zgjjqico.ffs@tglx/
