x86/bugs: Group MDS, TAA & Processor MMIO Stale Data mitigations

stable inclusion
from stable-v4.19.248
commit 54974c8714283feb5bf64df3bfe0f44267db5a3c
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I5D5RS


CVE: CVE-2022-21123,CVE-2022-21125,CVE-2022-21166

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

commit e5925fb8 upstream

MDS, TAA and Processor MMIO Stale Data mitigations rely on clearing CPU
buffers. Moreover, status of these mitigations affects each other.
During boot, it is important to maintain the order in which these
mitigations are selected. This is especially true for
md_clear_update_mitigation() that needs to be called after MDS, TAA and
Processor MMIO Stale Data mitigation selection is done.

Introduce md_clear_select_mitigation(), and select all these mitigations
from there. This reflects relationships between these mitigations and
ensures proper ordering.

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yipeng Zou <zouyipeng@huawei.com>
Reviewed-by: Zhang Jianhua <chris.zjh@huawei.com>
Reviewed-by: Liao Chang <liaochang1@huawei.com>
Reviewed-by: Liao Chang <liaochang1@huawei.com>
Reviewed-by: Liao Chang <liaochang1@huawei.com>
Reviewed-by: Liao Chang <liaochang1@huawei.com>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>