Commit ebca1770 authored by Fenghua Yu's avatar Fenghua Yu Committed by Thomas Gleixner
Browse files

Documentation/admin-guide: Change doc for split_lock_detect parameter 



Since #DB for bus lock detect changes the split_lock_detect parameter,
update the documentation for the changes.

Signed-off-by: default avatarFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarTony Luck <tony.luck@intel.com>
Acked-by: default avatarRandy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20210322135325.682257-4-fenghua.yu@intel.com
parent ebb1064e

Documentation/admin-guide/kernel-parameters.txt

+16 −6
Original line number Diff line number Diff line
@@ -5100,27 +5100,37 @@ 
	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

			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.

				  exception or the #DB exception. This mode is

				  the default on CPUs that support split lock

				  detection or bus lock detection. Default

				  behavior is by #AC if both features are

				  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 by #AC if

				  both features are enabled in hardware.



			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.