[mirror_ubuntu-artful-kernel.git] / arch / arm64 / Kconfig.debug

menu "Kernel hacking"

source "lib/Kconfig.debug"

config ARM64_PTDUMP
	bool "Export kernel pagetable layout to userspace via debugfs"
	depends on DEBUG_KERNEL
	select DEBUG_FS
        help
	  Say Y here if you want to show the kernel pagetable layout in a
	  debugfs file. This information is only useful for kernel developers
	  who are working in architecture specific areas of the kernel.
	  It is probably not a good idea to enable this feature in a production
	  kernel.
	  If in doubt, say "N"

config PID_IN_CONTEXTIDR
	bool "Write the current PID to the CONTEXTIDR register"
	help
	  Enabling this option causes the kernel to write the current PID to
	  the CONTEXTIDR register, at the expense of some additional
	  instructions during context switch. Say Y here only if you are
	  planning to use hardware trace tools with this kernel.

config ARM64_RANDOMIZE_TEXT_OFFSET
	bool "Randomize TEXT_OFFSET at build time"
	help
	  Say Y here if you want the image load offset (AKA TEXT_OFFSET)
	  of the kernel to be randomized at build-time. When selected,
	  this option will cause TEXT_OFFSET to be randomized upon any
	  build of the kernel, and the offset will be reflected in the
	  text_offset field of the resulting Image. This can be used to
	  fuzz-test bootloaders which respect text_offset.

	  This option is intended for bootloader and/or kernel testing
	  only. Bootloaders must make no assumptions regarding the value
	  of TEXT_OFFSET and platforms must not require a specific
	  value.

config DEBUG_SET_MODULE_RONX
        bool "Set loadable kernel module data as NX and text as RO"
        depends on MODULES
        help
          This option helps catch unintended modifications to loadable
          kernel module's text and read-only data. It also prevents execution
          of module data. Such protection may interfere with run-time code
          patching and dynamic kernel tracing - and they might also protect
          against certain classes of kernel exploits.
          If in doubt, say "N".

config DEBUG_RODATA
	bool "Make kernel text and rodata read-only"
	default y
	help
	  If this is set, kernel text and rodata will be made read-only. This
	  is to help catch accidental or malicious attempts to change the
	  kernel's executable code.

	  If in doubt, say Y

config DEBUG_ALIGN_RODATA
	depends on DEBUG_RODATA && ARM64_4K_PAGES
	bool "Align linker sections up to SECTION_SIZE"
	help
	  If this option is enabled, sections that may potentially be marked as
	  read only or non-executable will be aligned up to the section size of
	  the kernel. This prevents sections from being split into pages and
	  avoids a potential TLB penalty. The downside is an increase in
	  alignment and potentially wasted space. Turn on this option if
	  performance is more important than memory pressure.

	  If in doubt, say N

source "drivers/hwtracing/coresight/Kconfig"

endmenu
Commit	Line	Data
8c2c3df3 CM	1	menu "Kernel hacking"
	2
	3	source "lib/Kconfig.debug"
	4
c9465b4e LA	5	config ARM64_PTDUMP
	6	bool "Export kernel pagetable layout to userspace via debugfs"
	7	depends on DEBUG_KERNEL
	8	select DEBUG_FS
	9	help
	10	Say Y here if you want to show the kernel pagetable layout in a
	11	debugfs file. This information is only useful for kernel developers
	12	who are working in architecture specific areas of the kernel.
	13	It is probably not a good idea to enable this feature in a production
	14	kernel.
	15	If in doubt, say "N"
	16
ec45d1cf WD	17	config PID_IN_CONTEXTIDR
	18	bool "Write the current PID to the CONTEXTIDR register"
	19	help
	20	Enabling this option causes the kernel to write the current PID to
	21	the CONTEXTIDR register, at the expense of some additional
	22	instructions during context switch. Say Y here only if you are
	23	planning to use hardware trace tools with this kernel.
	24
da57a369 MR	25	config ARM64_RANDOMIZE_TEXT_OFFSET
	26	bool "Randomize TEXT_OFFSET at build time"
	27	help
	28	Say Y here if you want the image load offset (AKA TEXT_OFFSET)
	29	of the kernel to be randomized at build-time. When selected,
	30	this option will cause TEXT_OFFSET to be randomized upon any
	31	build of the kernel, and the offset will be reflected in the
	32	text_offset field of the resulting Image. This can be used to
	33	fuzz-test bootloaders which respect text_offset.
	34
	35	This option is intended for bootloader and/or kernel testing
	36	only. Bootloaders must make no assumptions regarding the value
	37	of TEXT_OFFSET and platforms must not require a specific
	38	value.
	39
11d91a77 LA	40	config DEBUG_SET_MODULE_RONX
	41	bool "Set loadable kernel module data as NX and text as RO"
	42	depends on MODULES
	43	help
	44	This option helps catch unintended modifications to loadable
	45	kernel module's text and read-only data. It also prevents execution
	46	of module data. Such protection may interfere with run-time code
	47	patching and dynamic kernel tracing - and they might also protect
	48	against certain classes of kernel exploits.
	49	If in doubt, say "N".
	50
da141706 LA	51	config DEBUG_RODATA
da141706 LA	52	bool "Make kernel text and rodata read-only"
57efac2f	53	default y
da141706 LA	54	help
	55	If this is set, kernel text and rodata will be made read-only. This
	56	is to help catch accidental or malicious attempts to change the
57efac2f	57	kernel's executable code.
da141706	58
57efac2f	59	If in doubt, say Y
da141706 LA	60
da141706 LA	61	config DEBUG_ALIGN_RODATA
755e70b7	62	depends on DEBUG_RODATA && ARM64_4K_PAGES
da141706 LA	63	bool "Align linker sections up to SECTION_SIZE"
	64	help
	65	If this option is enabled, sections that may potentially be marked as
	66	read only or non-executable will be aligned up to the section size of
	67	the kernel. This prevents sections from being split into pages and
	68	avoids a potential TLB penalty. The downside is an increase in
	69	alignment and potentially wasted space. Turn on this option if
	70	performance is more important than memory pressure.
	71
	72	If in doubt, say N
	73
01081f5a	74	source "drivers/hwtracing/coresight/Kconfig"
3288731e	75
8c2c3df3	76	endmenu