Merge tag 'x86-splitlock-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 splitlock updates from Ingo Molnar:

 - Add the "ratelimit:N" parameter to the split_lock_detect= boot
   option, to rate-limit the generation of bus-lock exceptions.

   This is both easier on system resources and kinder to offending
   applications than the current policy of outright killing them.

 - Document the split-lock detection feature and its parameters.

* tag 'x86-splitlock-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Documentation/x86: Add ratelimit in buslock.rst
  Documentation/admin-guide: Add bus lock ratelimit
  x86/bus_lock: Set rate limit for bus lock
  Documentation/x86: Add buslock.rst

1 files changed, 8 insertions, 0 deletions

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 1347b2c33451..34f5b30bcec8 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5278,6 +5278,14 @@
 				  exception. Default behavior is by #AC if
 				  both features are enabled in hardware.
 
+			ratelimit:N -
+				  Set system wide rate limit to N bus locks
+				  per second for bus lock detection.
+				  0 < N <= 1000.
+
+				  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"