From: Fenghua Yu <fenghua.yu@intel.com>
To: "Thomas Gleixner" <tglx@linutronix.de>,
"Borislav Petkov" <bp@alien8.de>,
"Ingo Molnar" <mingo@redhat.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Randy Dunlap" <rdunlap@infradead.org>,
"Tony Luck" <tony.luck@intel.com>,
"Christopherson Sean J" <sean.j.christopherson@intel.com>,
"Ashok Raj" <ashok.raj@intel.com>,
"Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "linux-kernel" <linux-kernel@vger.kernel.org>,
"x86" <x86@kernel.org>, Fenghua Yu <fenghua.yu@intel.com>
Subject: [PATCH RFC v3 4/4] Documentation/admin-guide: Change doc for split_lock_detect parameter
Date: Sat, 31 Oct 2020 00:27:14 +0000 [thread overview]
Message-ID: <20201031002714.3649728-5-fenghua.yu@intel.com> (raw)
In-Reply-To: <20201031002714.3649728-1-fenghua.yu@intel.com>
Since #DB for bus lock detect changes the split_lock_detect parameter,
update the documentation for the changes.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
---
Change Log:
- Simplify the documentation (Randy).
.../admin-guide/kernel-parameters.txt | 28 +++++++++++++++----
1 file changed, 23 insertions(+), 5 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 526d65d8573a..ee419ce659f5 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5044,27 +5044,45 @@
spia_peddr=
split_lock_detect=
- [X86] Enable split lock detection
+ [X86] Enable split lock detection or bus lock detection
When enabled (and if hardware support is present), atomic
instructions that access data across cache line
- boundaries will result in an alignment check exception.
+ boundaries will result in an alignment check exception
+ for split lock detection or a debug exception for
+ bus lock detection.
off - not enabled
warn - the kernel will emit rate limited warnings
about applications triggering the #AC
- exception. This mode is the default on CPUs
- that supports split lock detection.
+ exception or the #DB exception. This mode is
+ the default on CPUs that supports split lock
+ detection or bus lock detection. Default
+ behavior is from #DB if both features are
+ enabled in hardware.
fatal - the kernel will send SIGBUS to applications
- that trigger the #AC exception.
+ that trigger the #AC exception or the #DB
+ exception. Default behavior is from #AC
+ if both features are enabled in hardware.
+
+ ratelimit:N -
+ Set rate limit to N bus locks per second
+ for bus lock detection. 0 < N <= HZ/2 and
+ N is approximate. Only applied to non root
+ user.
+
+ N/A for split lock detection.
If an #AC exception is hit in the kernel or in
firmware (i.e. not while executing in user mode)
the kernel will oops in either "warn" or "fatal"
mode.
+ #DB exception for bus lock is triggered only when
+ CPL > 0.
+
srbds= [X86,INTEL]
Control the Special Register Buffer Data Sampling
(SRBDS) mitigation.
--
2.29.1
next prev parent reply other threads:[~2020-10-31 0:27 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-31 0:27 [PATCH RFC v3 0/4] x86/bus_lock: Enable bus lock detection Fenghua Yu
2020-10-31 0:27 ` [PATCH RFC v3 1/4] x86/cpufeatures: Enumerate #DB for " Fenghua Yu
2020-10-31 0:27 ` [PATCH RFC v3 2/4] x86/bus_lock: Handle warn and fatal in #DB for bus lock Fenghua Yu
2020-11-03 12:15 ` Xiaoyao Li
2020-11-06 20:31 ` Fenghua Yu
2020-10-31 0:27 ` [PATCH RFC v3 3/4] x86/bus_lock: Set rate limit " Fenghua Yu
2020-10-31 0:27 ` Fenghua Yu [this message]
2020-10-31 3:14 ` [PATCH RFC v3 4/4] Documentation/admin-guide: Change doc for split_lock_detect parameter Randy Dunlap
2020-11-02 17:03 ` Fenghua Yu
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