[Xen-devel,v3,11/13] xen/arm: Kconfig: Move HARDEN_BRANCH_PREDICTOR under "Architecture features"

Message ID 20180612113643.32020-12-julien.grall@arm.com
State New
Headers show
Series
  • xen/arm: SSBD (aka Spectre-v4) mitigation (XSA-263)
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Commit Message

Julien Grall June 12, 2018, 11:36 a.m.
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>

---
    Changes in v2:
        - Add Stefano's reviewed-by
---
 xen/arch/arm/Kconfig | 34 +++++++++++++++++-----------------
 1 file changed, 17 insertions(+), 17 deletions(-)

Patch

diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index 0e2d027060..4212c58171 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -83,6 +83,23 @@  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"
@@ -197,23 +214,6 @@  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