On 10/28/20 1:28 PM, Fenghua Yu wrote: > 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. > +
Hi, This appears to have quite a bit of duplicated lines.... > + 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. > -- ~Randy
