ARM: Spectre-BHB workaround

[sfrench/cifs-2.6.git] / arch / arm / mm / Kconfig

diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index 850329ea9bf8117ac3bf2e2bb4f63ae2c0e46620..9724c16e907671b83cdb2454cef76a0917a26366 100644 (file)
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -851,6 +851,16 @@ config HARDEN_BRANCH_PREDICTOR
 
           If unsure, say Y.
 
+config HARDEN_BRANCH_HISTORY
+       bool "Harden Spectre style attacks against branch history" if EXPERT
+       depends on CPU_SPECTRE
+       default y
+       help
+         Speculation attacks against some high-performance processors can
+         make use of branch history to influence future speculation. When
+         taking an exception, a sequence of branches overwrites the branch
+         history, or branch history is invalidated.
+
 config TLS_REG_EMUL
        bool
        select NEED_KUSER_HELPERS