[ Upstream commit f71e1d2ff8e6a183bd4004bc97c453ba527b7dc6 ] The SYSCALL instruction cannot really be disabled in compatibility mode. The best that can be done is to configure the CSTAR msr to point to a minimal handler. Currently this handler has a rather misleading name - ignore_sysret() as it's not really doing anything with sysret. Give it a more descriptive name. Signed-off-by: Nikolay Borisov <nik.borisov@suse.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20230623111409.3047467-3-nik.borisov@suse.com Stable-dep-of: ac8b270b61d4 ("x86/bhi: Avoid warning in #DB handler due to BHI mitigation") Signed-off-by: Sasha Levin <sashal@kernel.org>