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authorLinus Torvalds <torvalds@linux-foundation.org>2020-06-03 14:57:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-03 14:57:03 -0700
commitf1e455352b6f503532eb3637d0a6d991895e7856 (patch)
tree6a417c2068e0108d36fdbde03112d10578801707 /Documentation/admin-guide
parent38696e33e2bdf91cbbc7a2291dc6db862d9dfd42 (diff)
parentc893de12e1ef17b581eb2cf8fc9018ec0cbd07df (diff)
Merge tag 'kgdb-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux
Pull kgdb updates from Daniel Thompson: "By far the biggest change in this cycle are the changes that allow much earlier debug of systems that are hooked up via UART by taking advantage of the earlycon framework to implement the kgdb I/O hooks before handing over to the regular polling I/O drivers once they are available. When discussing Doug's work we also found and fixed an broken raw_smp_processor_id() sequence in in_dbg_master(). Also included are a collection of much smaller fixes and tweaks: a couple of tweaks to ged rid of doc gen or coccicheck warnings, future proof some internal calculations that made implicit power-of-2 assumptions and eliminate some rather weird handling of magic environment variables in kdb" * tag 'kgdb-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux: kdb: Remove the misfeature 'KDBFLAGS' kdb: Cleanup math with KDB_CMD_HISTORY_COUNT serial: amba-pl011: Support kgdboc_earlycon serial: 8250_early: Support kgdboc_earlycon serial: qcom_geni_serial: Support kgdboc_earlycon serial: kgdboc: Allow earlycon initialization to be deferred Documentation: kgdboc: Document new kgdboc_earlycon parameter kgdb: Don't call the deinit under spinlock kgdboc: Disable all the early code when kgdboc is a module kgdboc: Add kgdboc_earlycon to support early kgdb using boot consoles kgdboc: Remove useless #ifdef CONFIG_KGDB_SERIAL_CONSOLE in kgdboc kgdb: Prevent infinite recursive entries to the debugger kgdb: Delay "kgdbwait" to dbg_late_init() by default kgdboc: Use a platform device to handle tty drivers showing up late Revert "kgdboc: disable the console lock when in kgdb" kgdb: Disable WARN_CONSOLE_UNLOCKED for all kgdb kgdb: Return true in kgdb_nmi_poll_knock() kgdb: Drop malformed kernel doc comment kgdb: Fix spurious true from in_dbg_master()
Diffstat (limited to 'Documentation/admin-guide')
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt20
1 files changed, 20 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index f793951a8e53..52e63f3c8b07 100644
--- 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.