menu "Kernel hacking"

source "lib/Kconfig.debug"

config EARLY_PRINTK
	bool "Early printk" if EMBEDDED
	default y
	help
	  Write kernel log output directly into the VGA buffer or to a serial
	  port.

	  This is useful for kernel debugging when your machine crashes very
	  early before the console code is initialized. For normal operation
	  it is not recommended because it looks ugly and doesn't cooperate
	  with klogd/syslogd or the X server. You should normally N here,
	  unless you want to debug such a crash.

config KPROBES
	bool "Kprobes"
	depends on DEBUG_KERNEL
	help
	  Kprobes allows you to trap at almost any kernel address and
	  execute a callback function.  register_kprobe() establishes
	  a probepoint and specifies the callback.  Kprobes is useful
	  for kernel debugging, non-intrusive instrumentation and testing.
	  If in doubt, say "N".

config DEBUG_PAGEALLOC
	bool "Page alloc debugging"
	depends on DEBUG_KERNEL
	help
	  Unmap pages from the kernel linear mapping after free_pages().
	  This results in a large slowdown, but helps to find certain types
	  of memory corruptions.

config DEBUG_STACKOVERFLOW
	bool "Check for stack overflows"
	depends on DEBUG_KERNEL

config DEBUG_STACK_USAGE
	bool "Stack utilization instrumentation"
	depends on DEBUG_KERNEL
	help
	  Enables the display of the minimum amount of free stack which each
	  task has ever had available in the sysrq-T and sysrq-P debug output.

	  This option will slow down process creation somewhat.

config IRQSTACKS
	bool "Use separate IRQ stacks"
	help
	This option subsumes the IRQ stack implementation of the orig. 4KSTACK
	support.  You must use this if you select 4KB stacks! 

config STACK_SIZE_SHIFT
	int "Kernel stack size (12 => 4KB, 13 => 8KB, 14 => 16KB)"
	range 12 14
	default 12 if IRQSTACKS
	default 13
	help
	Select kernel stack size.  4KB stacks are best as they let
	the system scale further.  Use 8KB stacks if you have an 
	experimental kernel where a stack overlow with a 4KB stack
	might occur.  Use 16KB stacks if you want to safely support
	Windows device drivers using either Linuxant or ndiswrapper.

config STACK_WARN
	int "Print stack trace when stack grows beyond specified bytes"
	default 4096 if IRQSTACKS
	default 4096
	help
	The kernel will print a stack trace when the current stack exceeds
	the specified size.

config X86_STACK_CHECK
	bool "Aggressively check for stack overflows"
	default n
	help
	Say Y here to have the kernel attempt to detect when the per-task
	kernel stack overflows.

	Some older versions of gcc don't handle the -p option correctly.
	Kernprof is affected by the same problem, which is described here:
	http://oss.sgi.com/projects/kernprof/faq.html#Q9

	Basically, if you get oopses in __free_pages_ok during boot when
	you have this turned on, you need to fix gcc. The Redhat 2.96
	version and gcc-3.x seem to work.

	If not debugging a stack overflow problem, say N

config STACK_PANIC
	int "Panic when stack approaches with specified bytes of the stack limit"
	depends on X86_STACK_CHECK
	default 512 if IRQSTACKS
	default 512
	help
	Panic if the stack grows to within specified byte range.

config DEBUG_PAGEALLOC
	bool "Page alloc debugging"
	depends on DEBUG_KERNEL
	help
	  Unmap pages from the kernel linear mapping after free_pages().
	  This results in a large slowdown, but helps to find certain types
	  of memory corruptions.

config X86_FIND_SMP_CONFIG
	bool
	depends on X86_LOCAL_APIC || X86_VOYAGER
	default y

config X86_MPPARSE
	bool
	depends on X86_LOCAL_APIC && !X86_VISWS
	default y

endmenu