x86/amd: Use IBPB for firmware calls

stable inclusion
from stable-v5.10.134
commit b7b9e5cc8b24d6c800b2b7f8bba44c5914bd6c8f
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5ZVR7

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b7b9e5cc8b24d6c800b2b7f8bba44c5914bd6c8f



--------------------------------

commit 28a99e95 upstream.

On AMD IBRS does not prevent Retbleed; as such use IBPB before a
firmware call to flush the branch history state.

And because in order to do an EFI call, the kernel maps a whole lot of
the kernel page table into the EFI page table, do an IBPB just in case
in order to prevent the scenario of poisoning the BTB and causing an EFI
call using the unprotected RET there.

  [ bp: Massage. ]

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220715194550.793957-1-cascardo@canonical.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>

 Conflicts:
	arch/x86/include/asm/cpufeatures.h
Reviewed-by: Wei Li <liwei391@huawei.com>