Merge tag 'kgdb-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt...

[tomoyo/tomoyo-test1.git] / Documentation / admin-guide / kernel-parameters.txt

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 4379c6a..52e63f3 100644 (file)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1190,6 +1190,11 @@
                        This is designed to be used in conjunction with
                        the boot argument: earlyprintk=vga
 
+                       This parameter works in place of the kgdboc parameter
+                       but can only be used if the backing tty is available
+                       very early in the boot process. For early debugging
+                       via a serial port see kgdboc_earlycon instead.
+
        edd=            [EDD]
                        Format: {"off" | "on" | "skip[mbr]"}
 
@@ -2112,6 +2117,21 @@
                         kms, kbd format: kms,kbd
                         kms, kbd and serial format: kms,kbd,<ser_dev>[,baud]
 
+       kgdboc_earlycon=        [KGDB,HW]
+                       If the boot console provides the ability to read
+                       characters and can work in polling mode, you can use
+                       this parameter to tell kgdb to use it as a backend
+                       until the normal console is registered. Intended to
+                       be used together with the kgdboc parameter which
+                       specifies the normal console to transition to.
+
+                       The name of the early console should be specified
+                       as the value of this parameter. Note that the name of
+                       the early console might be different than the tty
+                       name passed to kgdboc. It's OK to leave the value
+                       blank and the first boot console that implements
+                       read() will be picked.
+
        kgdbwait        [KGDB] Stop kernel execution and enter the
                        kernel debugger at the earliest opportunity.
 
@@ -5093,6 +5113,12 @@
                        interruptions from clocksource watchdog are not
                        acceptable).
 
+       tsc_early_khz=  [X86] Skip early TSC calibration and use the given
+                       value instead. Useful when the early TSC frequency discovery
+                       procedure is not reliable, such as on overclocked systems
+                       with CPUID.16h support and partial CPUID.15h support.
+                       Format: <unsigned int>
+
        tsx=            [X86] Control Transactional Synchronization
                        Extensions (TSX) feature in Intel processors that
                        support TSX control.