Messages in this thread Patch in this message | | | From | Fenghua Yu <> | Subject | [PATCH RFC v2 4/4] Documentation: Change doc for split_lock_detect parameter | Date | Wed, 28 Oct 2020 20:28:04 +0000 |
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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> --- .../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
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