From ebca17707e38f2050b188d837bd4646b29a1b0c2 Mon Sep 17 00:00:00 2001 From: Fenghua Yu Date: Mon, 22 Mar 2021 13:53:25 +0000 Subject: [PATCH] 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: Fenghua Yu Signed-off-by: Thomas Gleixner Reviewed-by: Tony Luck Acked-by: Randy Dunlap Link: https://lore.kernel.org/r/20210322135325.682257-4-fenghua.yu@intel.com --- Documentation/admin-guide/kernel-parameters.txt | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 0454572..aef927c 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -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. -- 2.7.4