kgdb, powerpc: arch specific powerpc kgdb support

This patch removes the old kgdb reminants from ARCH=powerpc and
implements the new style arch specific stub for the common kgdb core
interface.

It is possible to have xmon and kgdb in the same kernel, but you
cannot use both at the same time because there is only one set of
debug hooks.

The arch specific kgdb implementation saves the previous state of the
debug hooks and restores them if you unconfigure the kgdb I/O driver.
Kgdb should have no impact on a kernel that has no kgdb I/O driver
configured.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>

arch/powerpc/Kconfig

@@ -112,6 +112,7 @@ config PPC
 	select HAVE_FTRACE
 	select HAVE_IDE
 	select HAVE_KPROBES
+	select HAVE_ARCH_KGDB
 	select HAVE_KRETPROBES
 	select HAVE_LMB
 	select HAVE_DMA_ATTRS if PPC64

arch/powerpc/Kconfig.debug

@@ -41,22 +41,6 @@ config HCALL_STATS
 	  This option will add a small amount of overhead to all hypervisor
 	  calls.
 
-config DEBUGGER
-	bool "Enable debugger hooks"
-	depends on DEBUG_KERNEL
-	help
-	  Include in-kernel hooks for kernel debuggers. Unless you are
-	  intending to debug the kernel, say N here.
-
-config KGDB
-	bool "Include kgdb kernel debugger"
-	depends on DEBUGGER && (BROKEN || PPC_GEN550 || 4xx)
-	select DEBUG_INFO
-	help
-	  Include in-kernel hooks for kgdb, the Linux kernel source level
-	  debugger.  See <http://kgdb.sourceforge.net/> for more information.
-	  Unless you are intending to debug the kernel, say N here.
-
 config CODE_PATCHING_SELFTEST
 	bool "Run self-tests of the code-patching code."
 	depends on DEBUG_KERNEL
@@ -67,36 +51,9 @@ config FTR_FIXUP_SELFTEST
 	depends on DEBUG_KERNEL
 	default n
 
-choice
-	prompt "Serial Port"
-	depends on KGDB
-	default KGDB_TTYS1
-
-config KGDB_TTYS0
-	bool "ttyS0"
-
-config KGDB_TTYS1
-	bool "ttyS1"
-
-config KGDB_TTYS2
-	bool "ttyS2"
-
-config KGDB_TTYS3
-	bool "ttyS3"
-
-endchoice
-
-config KGDB_CONSOLE
-	bool "Enable serial console thru kgdb port"
-	depends on KGDB && 8xx || CPM2
-	help
-	  If you enable this, all serial console messages will be sent
-	  over the gdb stub.
-	  If unsure, say N.
-
 config XMON
 	bool "Include xmon kernel debugger"
-	depends on DEBUGGER
+	depends on DEBUG_KERNEL
 	help
 	  Include in-kernel hooks for the xmon kernel monitor/debugger.
 	  Unless you are intending to debug the kernel, say N here.
@@ -126,6 +83,11 @@ config XMON_DISASSEMBLY
 	  to say Y here, unless you're building for a memory-constrained
 	  system.
 
+config DEBUGGER
+	bool
+	depends on KGDB || XMON
+	default y
+
 config IRQSTACKS
 	bool "Use separate kernel stacks when processing interrupts"
 	help

arch/powerpc/kernel/Makefile

@@ -74,6 +74,7 @@ obj-y				+= time.o prom.o traps.o setup-common.o \
 				   misc_$(CONFIG_WORD_SIZE).o
 obj-$(CONFIG_PPC32)		+= entry_32.o setup_32.o
 obj-$(CONFIG_PPC64)		+= dma_64.o iommu.o
+obj-$(CONFIG_KGDB)		+= kgdb.o
 obj-$(CONFIG_PPC_MULTIPLATFORM)	+= prom_init.o
 obj-$(CONFIG_MODULES)		+= ppc_ksyms.o
 obj-$(CONFIG_BOOTX_TEXT)	+= btext.o