[PATCH v7 16/21] x86/split_lock: Document the new sysfs file for split lock detection

[Fenghua Yu]

Add an ABI document entry for /sys/devices/system/cpu/split_lock_detect.

Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
---
 .../ABI/testing/sysfs-devices-system-cpu      | 22 +++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 9605dbd4b5b5..aad7b1698065 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -67,6 +67,28 @@ Description:	Discover NUMA node a CPU belongs to
 		/sys/devices/system/cpu/cpu42/node2 -> ../../node/node2
 
 
+What:		/sys/devices/system/cpu/split_lock_detect
+Date:		March 2019
+Contact:	Linux kernel mailing list <linux-kernel@xxxxxxxxxxxxxxx>
+Description:	(RW) Control split lock detection on Intel Tremont and
+		future CPUs
+
+		Reads return split lock detection status:
+			0: disabled
+			1: enabled
+
+		Writes enable or disable split lock detection:
+			The first character is one of 'Nn0' or [oO][fF] for off
+			disables the feature.
+			The first character is one of 'Yy1' or [oO][nN] for on
+			enables the feature.
+
+		Please note the interface only shows or controls global setting.
+		During run time, split lock detection on one CPU may be
+		disabled if split lock operation in kernel code happens on
+		the CPU. The interface doesn't show or control split lock
+		detection on individual CPU.
+
 What:		/sys/devices/system/cpu/cpu#/topology/core_id
 		/sys/devices/system/cpu/cpu#/topology/core_siblings
 		/sys/devices/system/cpu/cpu#/topology/core_siblings_list
-- 
2.19.1