Messages in this thread | | | Subject | Re: [PATCH RFC v3 4/4] Documentation/admin-guide: Change doc for split_lock_detect parameter | From | Randy Dunlap <> | Date | Fri, 30 Oct 2020 20:14:15 -0700 |
| |
Hi,
On 10/30/20 5:27 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.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
rate-limited
> 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
support
> + detection or bus lock detection. Default > + behavior is from #DB if both features are
I would say is by #DB
> + 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
and is by #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
non-root
> + user.
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. > +
thanks. -- ~Randy
| |