x86/speculation: Add Kconfig option for GDS

mainline inclusion
from mainline-v6.5-rc6
commit 53cf5797
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7XLNT
CVE: CVE-2022-40982

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=53cf5797f114ba2bd86d23a862302119848eff19



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commit 53cf5797 upstream

Gather Data Sampling (GDS) is mitigated in microcode. However, on
systems that haven't received the updated microcode, disabling AVX
can act as a mitigation. Add a Kconfig option that uses the microcode
mitigation if available and disables AVX otherwise. Setting this
option has no effect on systems not affected by GDS. This is the
equivalent of setting gather_data_sampling=force.

Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zeng Heng <zengheng4@huawei.com>