* Mark Brown:

On Mon, Jun 12, 2023 at 05:10:49PM -0700, Rick Edgecombe wrote:

quoted

+Enabling arch_prctl()'s
+=======================
+
+Elf features should be enabled by the loader using the below arch_prctl's. They
+are only supported in 64 bit user applications. These operate on the features
+on a per-thread basis. The enablement status is inherited on clone, so if the
+feature is enabled on the first thread, it will propagate to all the thread's
+in an app.

I appreciate it's very late in the development of this series but given
that there are very similar features on both arm64 and riscv would it
make sense to make these just regular prctl()s, arch_prctl() isn't used
on other architectures and it'd reduce the amount of arch specific work
that userspace needs to do if the interface is shared.

Has the Arm feature been fully disclosed?

I would expect the integration with stack switching and unwinding
differs between architectures even if the core mechanism is similar.
It's probably tempting to handle shadow stack placement differently,
too.

Thanks,
Florian