xen/arm: Kconfig: Move HARDEN_BRANCH_PREDICTOR under "Architecture features"

At the moment, HARDEN_BRANCH_PREDICTOR is not in any section making
impossible for the user to unselect it.

Also, it looks like we require to use 'expert = "y"' for showing the
option in expert mode.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index 2cbe9dd43bd636c87b44fffe4514b6a0c1b1204e..06ba4a4d6eb87f6d3675f4c3e7f5ec9d718f804d 100644 (file)
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -81,6 +81,23 @@ config ARM_SSBD
 
          If unsure, say Y.
 
+config HARDEN_BRANCH_PREDICTOR
+       bool "Harden the branch predictor against aliasing attacks" if EXPERT = "y"
+       default y
+       help
+         Speculation attacks against some high-performance processors rely on
+         being able to manipulate the branch predictor for a victim context by
+         executing aliasing branches in the attacker context.  Such attacks
+         can be partially mitigated against by clearing internal branch
+         predictor state and limiting the prediction logic in some situations.
+
+         This config option will take CPU-specific actions to harden the
+         branch predictor against aliasing attacks and may rely on specific
+         instruction sequences or control bits being set by the system
+         firmware.
+
+         If unsure, say Y.
+
 endmenu
 
 menu "ARM errata workaround via the alternative framework"
@@ -195,23 +212,6 @@ config ARM64_ERRATUM_834220
 
 endmenu
 
-config HARDEN_BRANCH_PREDICTOR
-       bool "Harden the branch predictor against aliasing attacks" if EXPERT
-       default y
-       help
-         Speculation attacks against some high-performance processors rely on
-         being able to manipulate the branch predictor for a victim context by
-         executing aliasing branches in the attacker context.  Such attacks
-         can be partially mitigated against by clearing internal branch
-         predictor state and limiting the prediction logic in some situations.
-
-         This config option will take CPU-specific actions to harden the
-         branch predictor against aliasing attacks and may rely on specific
-         instruction sequences or control bits being set by the system
-         firmware.
-
-         If unsure, say Y.
-
 config ARM64_HARDEN_BRANCH_PREDICTOR
     def_bool y if ARM_64 && HARDEN_BRANCH_PREDICTOR