Since #DB for bus lock detect changes the split_lock_detect parameter,
update the documentation for the changes.
Signed-off-by: Fenghua Yu <fenghua...@intel.com>
Reviewed-by: Tony Luck <tony.l...@intel.com>
---
.../admin-guide/kernel-parameters.txt | 47 +++++++++++++++----
1 file changed, 39 insertions(+), 8 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt
b/Documentation/admin-guide/kernel-parameters.txt
index 526d65d8573a..51312484c2b6 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5044,27 +5044,58 @@
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 an 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.
+ warn - Default mode.
- fatal - the kernel will send SIGBUS to applications
- that trigger the #AC exception.
+ If split lock detection is enabled in
+ hardware, the kernel will emit rate limited
+ warnings about applications triggering the #AC
+ exception.
+
+ If bus lock detection is enabled in hardware,
+ the kernel will emit rate limited warnings
+ about applications triggering the #DB
+ exception.
+
+ Default behavior is from bus lock detection
+ if both features are enabled in hardware.
+
+ fatal - If split lock detection is enabled in
+ hardware, the kernel will send SIGBUS to
+ applications that trigger the #AC exception.
+
+ If bus lock detection is enabled in hardware,
+ the kernel will send SIGBUS to application
+ that trigger the #DB exception.
+
+ Default behavior is from split lock detection
+ if both 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.
--
2.29.0
