CVE-2024-40944

In the Linux kernel, the following vulnerability has been resolved:

x86/kexec: Fix bug with call depth tracking

The call to cc_platform_has() triggers a fault and system crash if call depth
tracking is active because the GS segment has been reset by load_segments() and
GS_BASE is now 0 but call depth tracking uses per-CPU variables to operate.

Call cc_platform_has() earlier in the function when GS is still valid.

[ bp: Massage. ]