[mirror_ubuntu-jammy-kernel.git] / arch / x86 / Kconfig.debug

menu "Kernel hacking"

config TRACE_IRQFLAGS_SUPPORT
	def_bool y

source "lib/Kconfig.debug"

config EARLY_PRINTK
	bool "Early printk" if EMBEDDED && DEBUG_KERNEL
	default y
	depends on X86_32
	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 && HIBERNATION
	depends on X86_32

config DEBUG_PAGEALLOC
	bool "Debug page memory allocations"
	depends on DEBUG_KERNEL && !HIBERNATION && !HUGETLBFS
	depends on X86_32
	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
	depends on X86_32
	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
	def_bool y
	depends on X86_LOCAL_APIC || X86_VOYAGER
	depends on X86_32

config X86_MPPARSE
	def_bool y
	depends on X86_LOCAL_APIC && !X86_VISWS
	depends on X86_32

config DOUBLEFAULT
	default y
	bool "Enable doublefault exception handler" if EMBEDDED
	depends on X86_32
	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.

config IOMMU_DEBUG
	bool "Enable IOMMU debugging"
	depends on IOMMU && DEBUG_KERNEL
	depends on X86_64
	help
	  Force the IOMMU to on even when you have less than 4GB of
	  memory and add debugging code. On overflow always panic. And
	  allow to enable IOMMU leak tracing. Can be disabled at boot
	  time with iommu=noforce. This will also enable scatter gather
	  list merging.  Currently not recommended for production
	  code. When you use it make sure you have a big enough
	  IOMMU/AGP aperture.  Most of the options enabled by this can
	  be set more finegrained using the iommu= command line
	  options. See Documentation/x86_64/boot-options.txt for more
	  details.

config IOMMU_LEAK
	bool "IOMMU leak tracing"
	depends on DEBUG_KERNEL
	depends on IOMMU_DEBUG
	help
	  Add a simple leak tracer to the IOMMU code. This is useful when you
	  are debugging a buggy device driver that leaks IOMMU mappings.

#config X86_REMOTE_DEBUG
#	bool "kgdb debugging stub"

endmenu
Commit	Line	Data
1da177e4 LT	1	menu "Kernel hacking"
1da177e4 LT	2
55f327fa	3	config TRACE_IRQFLAGS_SUPPORT
d013a27c	4	def_bool y
55f327fa	5
1da177e4 LT	6	source "lib/Kconfig.debug"
	7
	8	config EARLY_PRINTK
	9	bool "Early printk" if EMBEDDED && DEBUG_KERNEL
	10	default y
d013a27c	11	depends on X86_32
1da177e4 LT	12	help
	13	Write kernel log output directly into the VGA buffer or to a serial
	14	port.
	15
	16	This is useful for kernel debugging when your machine crashes very
	17	early before the console code is initialized. For normal operation
	18	it is not recommended because it looks ugly and doesn't cooperate
	19	with klogd/syslogd or the X server. You should normally N here,
	20	unless you want to debug such a crash.
	21
	22	config DEBUG_STACKOVERFLOW
	23	bool "Check for stack overflows"
	24	depends on DEBUG_KERNEL
dab175f3 AB	25	help
	26	This option will cause messages to be printed if free stack space
	27	drops below a certain limit.
1da177e4	28
1da177e4 LT	29	config DEBUG_STACK_USAGE
	30	bool "Stack utilization instrumentation"
	31	depends on DEBUG_KERNEL
	32	help
	33	Enables the display of the minimum amount of free stack which each
	34	task has ever had available in the sysrq-T and sysrq-P debug output.
	35
	36	This option will slow down process creation somewhat.
	37
	38	comment "Page alloc debug is incompatible with Software Suspend on i386"
b0cb1a19	39	depends on DEBUG_KERNEL && HIBERNATION
d013a27c	40	depends on X86_32
1da177e4 LT	41
1da177e4 LT	42	config DEBUG_PAGEALLOC
4a2f0acf	43	bool "Debug page memory allocations"
b0cb1a19	44	depends on DEBUG_KERNEL && !HIBERNATION && !HUGETLBFS
d013a27c	45	depends on X86_32
1da177e4 LT	46	help
	47	Unmap pages from the kernel linear mapping after free_pages().
	48	This results in a large slowdown, but helps to find certain types
	49	of memory corruptions.
	50
63aaf308 AV	51	config DEBUG_RODATA
	52	bool "Write protect kernel read-only data structures"
	53	depends on DEBUG_KERNEL
	54	help
	55	Mark the kernel read-only data as write-protected in the pagetables,
	56	in order to catch accidental (and incorrect) writes to such const
	57	data. This option may have a slight performance impact because a
	58	portion of the kernel code won't be covered by a 2MB TLB anymore.
	59	If in doubt, say "N".
	60
1da177e4 LT	61	config 4KSTACKS
	62	bool "Use 4Kb for kernel stacks instead of 8Kb"
	63	depends on DEBUG_KERNEL
d013a27c	64	depends on X86_32
1da177e4 LT	65	help
	66	If you say Y here the kernel will use a 4Kb stacksize for the
	67	kernel stack attached to each process/thread. This facilitates
	68	running more threads on a system and also reduces the pressure
	69	on the VM subsystem for higher order allocations. This option
	70	will also use IRQ stacks to compensate for the reduced stackspace.
	71
	72	config X86_FIND_SMP_CONFIG
d013a27c	73	def_bool y
1da177e4	74	depends on X86_LOCAL_APIC \|\| X86_VOYAGER
d013a27c	75	depends on X86_32
1da177e4 LT	76
1da177e4 LT	77	config X86_MPPARSE
d013a27c	78	def_bool y
1da177e4	79	depends on X86_LOCAL_APIC && !X86_VISWS
d013a27c	80	depends on X86_32
1da177e4	81
102e41fd AK	82	config DOUBLEFAULT
	83	default y
	84	bool "Enable doublefault exception handler" if EMBEDDED
d013a27c RD	85	depends on X86_32
	86	help
	87	This option allows trapping of rare doublefault exceptions that
	88	would otherwise cause a system to silently reboot. Disabling this
	89	option saves about 4k and might cause you much additional grey
	90	hair.
	91
	92	config IOMMU_DEBUG
	93	bool "Enable IOMMU debugging"
	94	depends on IOMMU && DEBUG_KERNEL
	95	depends on X86_64
102e41fd	96	help
d013a27c RD	97	Force the IOMMU to on even when you have less than 4GB of
	98	memory and add debugging code. On overflow always panic. And
	99	allow to enable IOMMU leak tracing. Can be disabled at boot
	100	time with iommu=noforce. This will also enable scatter gather
	101	list merging. Currently not recommended for production
	102	code. When you use it make sure you have a big enough
	103	IOMMU/AGP aperture. Most of the options enabled by this can
	104	be set more finegrained using the iommu= command line
	105	options. See Documentation/x86_64/boot-options.txt for more
	106	details.
	107
	108	config IOMMU_LEAK
	109	bool "IOMMU leak tracing"
	110	depends on DEBUG_KERNEL
	111	depends on IOMMU_DEBUG
	112	help
	113	Add a simple leak tracer to the IOMMU code. This is useful when you
	114	are debugging a buggy device driver that leaks IOMMU mappings.
	115
	116	#config X86_REMOTE_DEBUG
	117	# bool "kgdb debugging stub"
102e41fd	118
1da177e4	119	endmenu