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-rw-r--r--arch/x86/Kconfig64
1 files changed, 48 insertions, 16 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index e31001ec4c07..80636caee07c 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -937,13 +937,7 @@ config NR_CPUS
approximately eight kilobytes to the kernel image.
config SCHED_SMT
- bool "SMT (Hyperthreading) scheduler support"
- depends on SMP
- ---help---
- SMT scheduler support improves the CPU scheduler's decision making
- when dealing with Intel Pentium 4 chips with HyperThreading at a
- cost of slightly increased overhead in some places. If unsure say
- N here.
+ def_bool y if SMP
config SCHED_MC
def_bool y
@@ -1761,6 +1755,51 @@ config X86_INTEL_MEMORY_PROTECTION_KEYS
If unsure, say y.
+choice
+ prompt "TSX enable mode"
+ depends on CPU_SUP_INTEL
+ default X86_INTEL_TSX_MODE_OFF
+ help
+ Intel's TSX (Transactional Synchronization Extensions) feature
+ allows to optimize locking protocols through lock elision which
+ can lead to a noticeable performance boost.
+
+ On the other hand it has been shown that TSX can be exploited
+ to form side channel attacks (e.g. TAA) and chances are there
+ will be more of those attacks discovered in the future.
+
+ Therefore TSX is not enabled by default (aka tsx=off). An admin
+ might override this decision by tsx=on the command line parameter.
+ Even with TSX enabled, the kernel will attempt to enable the best
+ possible TAA mitigation setting depending on the microcode available
+ for the particular machine.
+
+ This option allows to set the default tsx mode between tsx=on, =off
+ and =auto. See Documentation/kernel-parameters.txt for more
+ details.
+
+ Say off if not sure, auto if TSX is in use but it should be used on safe
+ platforms or on if TSX is in use and the security aspect of tsx is not
+ relevant.
+
+config X86_INTEL_TSX_MODE_OFF
+ bool "off"
+ help
+ TSX is disabled if possible - equals to tsx=off command line parameter.
+
+config X86_INTEL_TSX_MODE_ON
+ bool "on"
+ help
+ TSX is always enabled on TSX capable HW - equals the tsx=on command
+ line parameter.
+
+config X86_INTEL_TSX_MODE_AUTO
+ bool "auto"
+ help
+ TSX is enabled on TSX capable HW that is believed to be safe against
+ side channel attacks- equals the tsx=auto command line parameter.
+endchoice
+
config EFI
bool "EFI runtime service support"
depends on ACPI
@@ -2051,14 +2090,8 @@ config RANDOMIZE_MEMORY_PHYSICAL_PADDING
If unsure, leave at the default value.
config HOTPLUG_CPU
- bool "Support for hot-pluggable CPUs"
+ def_bool y
depends on SMP
- ---help---
- Say Y here to allow turning CPUs off and on. CPUs can be
- controlled through /sys/devices/system/cpu.
- ( Note: power management support will enable this option
- automatically on SMP systems. )
- Say N if you want to disable CPU hotplug.
config BOOTPARAM_HOTPLUG_CPU0
bool "Set default setting of cpu0_hotpluggable"
@@ -2581,8 +2614,7 @@ config OLPC
config OLPC_XO1_PM
bool "OLPC XO-1 Power Management"
- depends on OLPC && MFD_CS5535 && PM_SLEEP
- select MFD_CORE
+ depends on OLPC && MFD_CS5535=y && PM_SLEEP
---help---
Add support for poweroff and suspend of the OLPC XO-1 laptop.