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>,
"Tony Luck" <tony.luck@intel.com>,
"Randy Dunlap" <rdunlap@infradead.org>,
"Xiaoyao Li " <xiaoyao.li@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 v4 4/4] Documentation/admin-guide: Change doc for split_lock_detect parameter
Date: Tue, 24 Nov 2020 20:52:45 +0000 [thread overview]
Message-ID: <20201124205245.4164633-5-fenghua.yu@intel.com> (raw)
In-Reply-To: <20201124205245.4164633-1-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>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
---
Change Log:
v4:
- Fix a ratelimit wording issue in the doc (Randy).
- Patch 4 is acked by Randy (Randy).
v3:
- Enable Bus Lock Detection when fatal to handle bus lock from non-WB
(PeterZ).
v1:
- Fix a few wording issues (Randy).
RFC v2:
- Simplify the documentation (Randy).
.../admin-guide/kernel-parameters.txt | 30 +++++++++++++++----
1 file changed, 24 insertions(+), 6 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 44fde25bb221..28228539b02a 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5051,27 +5051,45 @@
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
+ 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 support split lock
+ detection or bus lock detection. Default
+ behavior is by #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. If both features are enabled in
+ hardware, split lock triggers #AC and bus
+ lock from non-WB triggers #DB.
+
+ ratelimit:N -
+ Set rate limit to N bus locks per second
+ for bus lock detection. 0 < N <= HZ/2.
+ Only applied to non-root users.
+
+ 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.
--
2.29.2
next prev parent reply other threads:[~2020-11-24 20:53 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-24 20:52 [PATCH v4 0/4] x86/bus_lock: Enable bus lock detection Fenghua Yu
2020-11-24 20:52 ` [PATCH v4 1/4] x86/cpufeatures: Enumerate #DB for " Fenghua Yu
2021-01-27 21:13 ` Thomas Gleixner
2021-01-27 22:39 ` Yu, Fenghua
2021-01-27 23:23 ` Thomas Gleixner
2020-11-24 20:52 ` [PATCH v4 2/4] x86/bus_lock: Handle warn and fatal in #DB for bus lock Fenghua Yu
2021-01-27 21:16 ` Thomas Gleixner
2020-11-24 20:52 ` [PATCH v4 3/4] x86/bus_lock: Set rate limit " Fenghua Yu
2021-01-27 21:57 ` Thomas Gleixner
2020-11-24 20:52 ` Fenghua Yu [this message]
2021-01-27 22:09 ` [PATCH v4 4/4] Documentation/admin-guide: Change doc for split_lock_detect parameter Thomas Gleixner
2020-12-02 20:36 ` [PATCH v4 0/4] x86/bus_lock: Enable bus lock detection Yu, Fenghua
2021-01-04 19:42 ` Fenghua Yu
2021-01-25 19:27 ` Fenghua Yu
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