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()

lib/Kconfig.kgdb

@@ -124,4 +124,22 @@ config KDB_CONTINUE_CATASTROPHIC
 	  CONFIG_KDB_CONTINUE_CATASTROPHIC == 2. KDB forces a reboot.
 	  If you are not sure, say 0.
 
+config ARCH_HAS_EARLY_DEBUG
+	bool
+	default n
+	help
+	  If an architecture can definitely handle entering the debugger
+	  when early_param's are parsed then it select this config.
+	  Otherwise, if "kgdbwait" is passed on the kernel command line it
+	  won't actually be processed until dbg_late_init() just after the
+	  call to kgdb_arch_late() is made.
+
+	  NOTE: Even if this isn't selected by an architecture we will
+	  still try to register kgdb to handle breakpoints and crashes
+	  when early_param's are parsed, we just won't act on the
+	  "kgdbwait" parameter until dbg_late_init().  If you get a
+	  crash and try to drop into kgdb somewhere between these two
+	  places you might or might not end up being able to use kgdb
+	  depending on exactly how far along the architecture has initted.
+
 endif # KGDB