On Tue, 18 Jun 2019, Fenghua Yu wrote: > It is useful for development and debugging to document the new debugfs > interface /sys/kernel/debug/x86/split_lock_detect. > > A new debugfs documentation is created to describe the split lock detection > interface. In the future, more entries may be added in the documentation to > describe other interfaces under /sys/kernel/debug/x86 directory. > > Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx> > --- > Documentation/ABI/testing/debugfs-x86 | 21 +++++++++++++++++++++ > 1 file changed, 21 insertions(+) > create mode 100644 Documentation/ABI/testing/debugfs-x86 > > diff --git a/Documentation/ABI/testing/debugfs-x86 b/Documentation/ABI/testing/debugfs-x86 > new file mode 100644 > index 000000000000..17a1e9ed6712 > --- /dev/null > +++ b/Documentation/ABI/testing/debugfs-x86 > @@ -0,0 +1,21 @@ > +What: /sys/kernel/debugfs/x86/split_lock_detect > +Date: May 2019 > +Contact: Linux kernel mailing list <linux-kernel@xxxxxxxxxxxxxxx> > +Description: (RW) Control split lock detection on Intel Tremont and > + future CPUs > + > + Reads return split lock detection status: > + 0: disabled > + 1: enabled > + > + Writes enable or disable split lock detection: > + The first character is one of 'Nn0' or [oO][fF] for off > + disables the feature. > + The first character is one of 'Yy1' or [oO][nN] for on > + enables the feature. > + > + Please note the interface only shows or controls global setting. > + During run time, split lock detection on one CPU may be > + disabled if split lock operation in kernel code happens on > + the CPU. The interface doesn't show or control split lock > + detection on individual CPU. But it should show that the debug output for the kernel has been globally disabled instead of merily stating 'enabled' while it's already disabled on a bunch on CPUs. I fundamentally despise inconsistent information. Even in debugfs files inconsistency is a pain because it make debugging via mail/ bugzille etc. unnecessarily cumbersome. Thanks, tglx
