[linux-2.6-block.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 STRICT_DEVMEM
	bool "Filter access to /dev/mem"
	depends on MMU
	help
	  If this option is disabled, you allow userspace (root) access to all
	  of memory, including kernel and userspace memory. Accidental
	  access to this is obviously disastrous, but specific access can
	  be used by people debugging the kernel.

	  If this option is switched on, the /dev/mem file only allows
	  userspace access to memory mapped peripherals.

	  If in doubt, say Y.

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"
	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. Additionally splits rodata from kernel
	  text so it can be made explicitly non-executable.

          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
d253b440 LA	17	config STRICT_DEVMEM
	18	bool "Filter access to /dev/mem"
	19	depends on MMU
	20	help
	21	If this option is disabled, you allow userspace (root) access to all
	22	of memory, including kernel and userspace memory. Accidental
	23	access to this is obviously disastrous, but specific access can
	24	be used by people debugging the kernel.
	25
	26	If this option is switched on, the /dev/mem file only allows
	27	userspace access to memory mapped peripherals.
	28
	29	If in doubt, say Y.
	30
ec45d1cf WD	31	config PID_IN_CONTEXTIDR
	32	bool "Write the current PID to the CONTEXTIDR register"
	33	help
	34	Enabling this option causes the kernel to write the current PID to
	35	the CONTEXTIDR register, at the expense of some additional
	36	instructions during context switch. Say Y here only if you are
	37	planning to use hardware trace tools with this kernel.
	38
da57a369 MR	39	config ARM64_RANDOMIZE_TEXT_OFFSET
	40	bool "Randomize TEXT_OFFSET at build time"
	41	help
	42	Say Y here if you want the image load offset (AKA TEXT_OFFSET)
	43	of the kernel to be randomized at build-time. When selected,
	44	this option will cause TEXT_OFFSET to be randomized upon any
	45	build of the kernel, and the offset will be reflected in the
	46	text_offset field of the resulting Image. This can be used to
	47	fuzz-test bootloaders which respect text_offset.
	48
	49	This option is intended for bootloader and/or kernel testing
	50	only. Bootloaders must make no assumptions regarding the value
	51	of TEXT_OFFSET and platforms must not require a specific
	52	value.
	53
11d91a77 LA	54	config DEBUG_SET_MODULE_RONX
	55	bool "Set loadable kernel module data as NX and text as RO"
	56	depends on MODULES
	57	help
	58	This option helps catch unintended modifications to loadable
	59	kernel module's text and read-only data. It also prevents execution
	60	of module data. Such protection may interfere with run-time code
	61	patching and dynamic kernel tracing - and they might also protect
	62	against certain classes of kernel exploits.
	63	If in doubt, say "N".
	64
da141706 LA	65	config DEBUG_RODATA
	66	bool "Make kernel text and rodata read-only"
	67	help
	68	If this is set, kernel text and rodata will be made read-only. This
	69	is to help catch accidental or malicious attempts to change the
	70	kernel's executable code. Additionally splits rodata from kernel
	71	text so it can be made explicitly non-executable.
	72
	73	If in doubt, say Y
	74
	75	config DEBUG_ALIGN_RODATA
755e70b7	76	depends on DEBUG_RODATA && ARM64_4K_PAGES
da141706 LA	77	bool "Align linker sections up to SECTION_SIZE"
	78	help
	79	If this option is enabled, sections that may potentially be marked as
	80	read only or non-executable will be aligned up to the section size of
	81	the kernel. This prevents sections from being split into pages and
	82	avoids a potential TLB penalty. The downside is an increase in
	83	alignment and potentially wasted space. Turn on this option if
	84	performance is more important than memory pressure.
	85
	86	If in doubt, say N
	87
01081f5a	88	source "drivers/hwtracing/coresight/Kconfig"
3288731e	89
8c2c3df3	90	endmenu