x86: Enable Intel Indirect Branch Tracking (IBT)
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1874115
Enable Intel Indirect Branch Tracking (IBT) in the kernel, which is a security hardening feature which requires that all indirect branch targets have the ENDBR instruction.
Testing: Booted on Sapphire Rapids. The IBT selftest succeeded. Used 'gdb /proc/kcore' to verify that meminfo_proc_show() starts with an ENDBR, and other functions which don't have pointer references to them start with NOP.
Signed-off-by: Josh Poimboeuf jpoimboe@redhat.com
Edited by Josh Poimboeuf