2 files changed, 9 insertions, 1 deletions

diff --git a/Documentation/x86/x86_64/boot-options.txt b/Documentation/x86/x86_64/boot-options.txt
index 63fca718256e..0ee5e3b212f3 100644
--- a/Documentation/x86/x86_64/boot-options.txt
+++ b/Documentation/x86/x86_64/boot-options.txt
@@ -15,13 +15,17 @@ Machine check
                in a reboot. On Intel systems it is enabled by default.
    mce=nobootlog
                 Disable boot machine check logging.
-   mce=tolerancelevel (number)
+   mce=tolerancelevel[,monarchtimeout] (number,number)
+                tolerance levels:
                 0: always panic on uncorrected errors, log corrected errors
                 1: panic or SIGBUS on uncorrected errors, log corrected errors
                 2: SIGBUS or log uncorrected errors, log corrected errors
                 3: never panic or SIGBUS, log all errors (for testing only)
                 Default is 1
                 Can be also set using sysfs which is preferable.
+                monarchtimeout:
+                Sets the time in us to wait for other CPUs on machine checks. 0
+                to disable.
 
    nomce (for compatibility with i386): same as mce=off
 
diff --git a/Documentation/x86/x86_64/machinecheck b/Documentation/x86/x86_64/machinecheck
index a4fdb25446e0..b1fb30273286 100644
--- a/Documentation/x86/x86_64/machinecheck
+++ b/Documentation/x86/x86_64/machinecheck
@@ -69,6 +69,10 @@ trigger
         Program to run when a machine check event is detected.
         This is an alternative to running mcelog regularly from cron
         and allows to detect events faster.
+monarch_timeout
+        How long to wait for the other CPUs to machine check too on a
+        exception. 0 to disable waiting for other CPUs.
+        Unit: us
 
 TBD document entries for AMD threshold interrupt configuration