x86/speculation: Include unprivileged eBPF status in Spectre v2 mitigation reporting

stable inclusion
from stable-v4.19.234
commit 995629e1d8e6751936c6e2b738f70b392b0461de
category: bugfix
bugzilla: 186453, https://gitee.com/src-openeuler/kernel/issues/I50WBM


CVE: CVE-2022-0001

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

commit 44a3918c8245ab10c6c9719dd12e7a8d291980d8 upstream.

With unprivileged eBPF enabled, eIBRS (without retpoline) is vulnerable
to Spectre v2 BHB-based attacks.

When both are enabled, print a warning message and report it in the
'spectre_v2' sysfs vulnerabilities file.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
[fllinden@amazon.com: backported to 4.19]
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Conflicts:
    kernel/sysctl.c

Signed-off-by: Chen Jiahao <chenjiahao16@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Reviewed-by: Liao Chang <liaochang1@huawei.com>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>