On Feb 26, 2020, at 6:11 PM, H.J. Lu [off-list ref] wrote:

On Wed, Feb 26, 2020 at 5:16 PM Dave Hansen [off-list ref] wrote:

quoted

On 2/26/20 5:02 PM, H.J. Lu wrote:

quoted

quoted

That way everybody with old toolchains can still build the kernel (and
run/test code with your config option on, btw...).

CET requires a complete new OS image from kernel, toolchain, run-time.
CET enabled kernel without the rest of updated OS won't give you CET
at all.

If you require a new toolchain, nobody even builds your fancy feature.
Probably including 0day and all of the lazy maintainers with crufty old
distros.

GCC 8 or above is needed since vDSO must be compiled with
--fcf-protection=branch.

Fair enough. I don’t particularly want to carry a gross hack to add the ENDBRANCHes without compiler support.