[linux-2.6-block.git] / arch / i386 / Kconfig.debug

menu "Kernel hacking"

source "lib/Kconfig.debug"

config EARLY_PRINTK
	bool "Early printk" if EMBEDDED && DEBUG_KERNEL
	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 DEBUG_STACKOVERFLOW
	bool "Check for stack overflows"
	depends on DEBUG_KERNEL
	help
	  This option will cause messages to be printed if free stack space
	  drops below a certain limit.

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.

comment "Page alloc debug is incompatible with Software Suspend on i386"
	depends on DEBUG_KERNEL && SOFTWARE_SUSPEND

config DEBUG_PAGEALLOC
	bool "Debug page memory allocations"
	depends on DEBUG_KERNEL && !SOFTWARE_SUSPEND && !HUGETLBFS
	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_RODATA
	bool "Write protect kernel read-only data structures"
	depends on DEBUG_KERNEL
	help
	  Mark the kernel read-only data as write-protected in the pagetables,
	  in order to catch accidental (and incorrect) writes to such const
	  data. This option may have a slight performance impact because a
	  portion of the kernel code won't be covered by a 2MB TLB anymore.
	  If in doubt, say "N".

config 4KSTACKS
	bool "Use 4Kb for kernel stacks instead of 8Kb"
	depends on DEBUG_KERNEL
	help
	  If you say Y here the kernel will use a 4Kb stacksize for the
	  kernel stack attached to each process/thread. This facilitates
	  running more threads on a system and also reduces the pressure
	  on the VM subsystem for higher order allocations. This option
	  will also use IRQ stacks to compensate for the reduced stackspace.

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

config DOUBLEFAULT
	default y
	bool "Enable doublefault exception handler" if EMBEDDED
	help
          This option allows trapping of rare doublefault exceptions that
          would otherwise cause a system to silently reboot. Disabling this
          option saves about 4k and might cause you much additional grey
          hair.

endmenu
Commit	Line	Data
1da177e4 LT	1	menu "Kernel hacking"
	2
	3	source "lib/Kconfig.debug"
	4
	5	config EARLY_PRINTK
	6	bool "Early printk" if EMBEDDED && DEBUG_KERNEL
	7	default y
	8	help
	9	Write kernel log output directly into the VGA buffer or to a serial
	10	port.
	11
	12	This is useful for kernel debugging when your machine crashes very
	13	early before the console code is initialized. For normal operation
	14	it is not recommended because it looks ugly and doesn't cooperate
	15	with klogd/syslogd or the X server. You should normally N here,
	16	unless you want to debug such a crash.
	17
	18	config DEBUG_STACKOVERFLOW
	19	bool "Check for stack overflows"
	20	depends on DEBUG_KERNEL
dab175f3 AB	21	help
	22	This option will cause messages to be printed if free stack space
	23	drops below a certain limit.
1da177e4	24
1da177e4 LT	25	config DEBUG_STACK_USAGE
	26	bool "Stack utilization instrumentation"
	27	depends on DEBUG_KERNEL
	28	help
	29	Enables the display of the minimum amount of free stack which each
	30	task has ever had available in the sysrq-T and sysrq-P debug output.
	31
	32	This option will slow down process creation somewhat.
	33
	34	comment "Page alloc debug is incompatible with Software Suspend on i386"
	35	depends on DEBUG_KERNEL && SOFTWARE_SUSPEND
	36
	37	config DEBUG_PAGEALLOC
4a2f0acf	38	bool "Debug page memory allocations"
a7d06ca7	39	depends on DEBUG_KERNEL && !SOFTWARE_SUSPEND && !HUGETLBFS
1da177e4 LT	40	help
	41	Unmap pages from the kernel linear mapping after free_pages().
	42	This results in a large slowdown, but helps to find certain types
	43	of memory corruptions.
	44
63aaf308 AV	45	config DEBUG_RODATA
	46	bool "Write protect kernel read-only data structures"
	47	depends on DEBUG_KERNEL
	48	help
	49	Mark the kernel read-only data as write-protected in the pagetables,
	50	in order to catch accidental (and incorrect) writes to such const
	51	data. This option may have a slight performance impact because a
	52	portion of the kernel code won't be covered by a 2MB TLB anymore.
	53	If in doubt, say "N".
	54
1da177e4 LT	55	config 4KSTACKS
	56	bool "Use 4Kb for kernel stacks instead of 8Kb"
	57	depends on DEBUG_KERNEL
	58	help
	59	If you say Y here the kernel will use a 4Kb stacksize for the
	60	kernel stack attached to each process/thread. This facilitates
	61	running more threads on a system and also reduces the pressure
	62	on the VM subsystem for higher order allocations. This option
	63	will also use IRQ stacks to compensate for the reduced stackspace.
	64
	65	config X86_FIND_SMP_CONFIG
	66	bool
	67	depends on X86_LOCAL_APIC \|\| X86_VOYAGER
	68	default y
	69
	70	config X86_MPPARSE
	71	bool
	72	depends on X86_LOCAL_APIC && !X86_VISWS
	73	default y
	74
102e41fd AK	75	config DOUBLEFAULT
	76	default y
	77	bool "Enable doublefault exception handler" if EMBEDDED
	78	help
	79	This option allows trapping of rare doublefault exceptions that
	80	would otherwise cause a system to silently reboot. Disabling this
	81	option saves about 4k and might cause you much additional grey
	82	hair.
	83
1da177e4	84	endmenu