mirror of
https://github.com/FEX-Emu/linux.git
synced 2025-02-23 14:06:06 +00:00

In long mode the %cs is largely a relic. However there are a few cases like iret where it matters that we have a valid value. Without this patch it is possible to enter the kernel in startup_64 without setting %cs to a valid value. With this patch we don't care what %cs value we enter the kernel with, so long as the cs shadow register indicates it is a privileged code segment. Thanks to Magnus Damm for finding this problem and posting the first workable patch. I have moved the jump to set %cs down a few instructions so we don't need to take an extra jump. Which keeps the code simpler. Signed-of-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andi Kleen <ak@suse.de>