Intel: x86/insn-eval: Add support for 64-bit kernel mode

mainline inclusion
from mainline-v5.6-rc1
commit 7be44127
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I47H3V


CVE: NA

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

commit 7be44127 upstream
Backport summary: Backport to kernel 4.19.57 to enhance MCA-R for copyin

To support evaluating 64-bit kernel mode instructions:

* Replace existing checks for user_64bit_mode() with a new helper that
checks whether code is being executed in either 64-bit kernel mode or
64-bit user mode.

* Select the GS base depending on whether the instruction is being
evaluated in kernel mode.

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: kasan-dev@googlegroups.com
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20191218231150.12139-1-jannh@google.com


Signed-off-by: Youquan Song <youquan.song@intel.com>
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>