linux-kernel - [PATCH v9 15/17] x86/split_lock: Add documentation for split lock detection interface

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Date:   Tue, 18 Jun 2019 15:41:17 -0700
From:   Fenghua Yu <fenghua.yu@...el.com>
To:     "Thomas Gleixner" <tglx@...utronix.de>,
        "Ingo Molnar" <mingo@...hat.com>, "Borislav Petkov" <bp@...en8.de>,
        "H Peter Anvin" <hpa@...or.com>,
        "Peter Zijlstra" <peterz@...radead.org>,
        "Andrew Morton" <akpm@...ux-foundation.org>,
        "Dave Hansen" <dave.hansen@...el.com>,
        "Paolo Bonzini" <pbonzini@...hat.com>,
        "Radim Krcmar" <rkrcmar@...hat.com>,
        "Christopherson Sean J" <sean.j.christopherson@...el.com>,
        "Ashok Raj" <ashok.raj@...el.com>,
        "Tony Luck" <tony.luck@...el.com>,
        "Dan Williams" <dan.j.williams@...el.com>,
        "Xiaoyao Li " <xiaoyao.li@...el.com>,
        "Sai Praneeth Prakhya" <sai.praneeth.prakhya@...el.com>,
        "Ravi V Shankar" <ravi.v.shankar@...el.com>
Cc:     "linux-kernel" <linux-kernel@...r.kernel.org>,
        "x86" <x86@...nel.org>, kvm@...r.kernel.org,
        Fenghua Yu <fenghua.yu@...el.com>
Subject: [PATCH v9 15/17] x86/split_lock: Add documentation for split lock detection interface

It is useful for development and debugging to document the new debugfs
interface /sys/kernel/debug/x86/split_lock_detect.

A new debugfs documentation is created to describe the split lock detection
interface. In the future, more entries may be added in the documentation to
describe other interfaces under /sys/kernel/debug/x86 directory.

Signed-off-by: Fenghua Yu <fenghua.yu@...el.com>
---
 Documentation/ABI/testing/debugfs-x86 | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 Documentation/ABI/testing/debugfs-x86

diff --git a/Documentation/ABI/testing/debugfs-x86 b/Documentation/ABI/testing/debugfs-x86
new file mode 100644
index 000000000000..17a1e9ed6712
--- /dev/null
+++ b/Documentation/ABI/testing/debugfs-x86
@@ -0,0 +1,21 @@
+What:		/sys/kernel/debugfs/x86/split_lock_detect
+Date:		May 2019
+Contact:	Linux kernel mailing list <linux-kernel@...r.kernel.org>
+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.
-- 
2.19.1