[linux-2.6-block.git] / arch / arm64 / Kconfig.debug

# SPDX-License-Identifier: GPL-2.0-only

config ARM64_PTDUMP_CORE
	def_bool n

config ARM64_PTDUMP_DEBUGFS
	bool "Export kernel pagetable layout to userspace via debugfs"
	depends on DEBUG_KERNEL
	select ARM64_PTDUMP_CORE
	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_WX
	bool "Warn on W+X mappings at boot"
	select ARM64_PTDUMP_CORE
	---help---
	  Generate a warning if any W+X mappings are found at boot.

	  This is useful for discovering cases where the kernel is leaving
	  W+X mappings after applying NX, as such mappings are a security risk.
	  This check also includes UXN, which should be set on all kernel
	  mappings.

	  Look for a message in dmesg output like this:

	    arm64/mm: Checked W+X mappings: passed, no W+X pages found.

	  or like this, if the check failed:

	    arm64/mm: Checked W+X mappings: FAILED, <N> W+X pages found.

	  Note that even if the check fails, your kernel is possibly
	  still fine, as W+X mappings are not a security hole in
	  themselves, what they do is that they make the exploitation
	  of other unfixed kernel bugs easier.

	  There is no runtime or memory usage effect of this option
	  once the kernel has booted up - it's a one time check.

	  If in doubt, say "Y".

config DEBUG_ALIGN_RODATA
	depends on STRICT_KERNEL_RWX
	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.

config DEBUG_EFI
	depends on EFI && DEBUG_INFO
	bool "UEFI debugging"
	help
	  Enable this option to include EFI specific debugging features into
	  the kernel that are only useful when using a debug build of the
	  UEFI firmware

config ARM64_RELOC_TEST
	depends on m
	tristate "Relocation testing module"

source "drivers/hwtracing/coresight/Kconfig"
Commit	Line	Data
ec8f24b7	1	# SPDX-License-Identifier: GPL-2.0-only
8c2c3df3	2
4ddb9bf8 LA	3	config ARM64_PTDUMP_CORE
	4	def_bool n
	5
	6	config ARM64_PTDUMP_DEBUGFS
c9465b4e LA	7	bool "Export kernel pagetable layout to userspace via debugfs"
c9465b4e LA	8	depends on DEBUG_KERNEL
4ddb9bf8	9	select ARM64_PTDUMP_CORE
c9465b4e LA	10	select DEBUG_FS
	11	help
	12	Say Y here if you want to show the kernel pagetable layout in a
	13	debugfs file. This information is only useful for kernel developers
	14	who are working in architecture specific areas of the kernel.
	15	It is probably not a good idea to enable this feature in a production
	16	kernel.
604c8e67 MR	17
604c8e67 MR	18	If in doubt, say N.
c9465b4e	19
ec45d1cf WD	20	config PID_IN_CONTEXTIDR
	21	bool "Write the current PID to the CONTEXTIDR register"
	22	help
	23	Enabling this option causes the kernel to write the current PID to
	24	the CONTEXTIDR register, at the expense of some additional
	25	instructions during context switch. Say Y here only if you are
	26	planning to use hardware trace tools with this kernel.
	27
da57a369 MR	28	config ARM64_RANDOMIZE_TEXT_OFFSET
	29	bool "Randomize TEXT_OFFSET at build time"
	30	help
	31	Say Y here if you want the image load offset (AKA TEXT_OFFSET)
	32	of the kernel to be randomized at build-time. When selected,
	33	this option will cause TEXT_OFFSET to be randomized upon any
	34	build of the kernel, and the offset will be reflected in the
	35	text_offset field of the resulting Image. This can be used to
	36	fuzz-test bootloaders which respect text_offset.
	37
	38	This option is intended for bootloader and/or kernel testing
	39	only. Bootloaders must make no assumptions regarding the value
	40	of TEXT_OFFSET and platforms must not require a specific
	41	value.
	42
1404d6f1 LA	43	config DEBUG_WX
	44	bool "Warn on W+X mappings at boot"
	45	select ARM64_PTDUMP_CORE
	46	---help---
	47	Generate a warning if any W+X mappings are found at boot.
	48
	49	This is useful for discovering cases where the kernel is leaving
	50	W+X mappings after applying NX, as such mappings are a security risk.
	51	This check also includes UXN, which should be set on all kernel
	52	mappings.
	53
	54	Look for a message in dmesg output like this:
	55
	56	arm64/mm: Checked W+X mappings: passed, no W+X pages found.
	57
	58	or like this, if the check failed:
	59
	60	arm64/mm: Checked W+X mappings: FAILED, <N> W+X pages found.
	61
	62	Note that even if the check fails, your kernel is possibly
	63	still fine, as W+X mappings are not a security hole in
	64	themselves, what they do is that they make the exploitation
	65	of other unfixed kernel bugs easier.
	66
	67	There is no runtime or memory usage effect of this option
	68	once the kernel has booted up - it's a one time check.
	69
	70	If in doubt, say "Y".
	71
da141706	72	config DEBUG_ALIGN_RODATA
0f5bf6d0	73	depends on STRICT_KERNEL_RWX
da141706 LA	74	bool "Align linker sections up to SECTION_SIZE"
	75	help
	76	If this option is enabled, sections that may potentially be marked as
	77	read only or non-executable will be aligned up to the section size of
	78	the kernel. This prevents sections from being split into pages and
	79	avoids a potential TLB penalty. The downside is an increase in
	80	alignment and potentially wasted space. Turn on this option if
	81	performance is more important than memory pressure.
	82
604c8e67	83	If in doubt, say N.
da141706	84
757b435a AB	85	config DEBUG_EFI
	86	depends on EFI && DEBUG_INFO
	87	bool "UEFI debugging"
	88	help
	89	Enable this option to include EFI specific debugging features into
	90	the kernel that are only useful when using a debug build of the
	91	UEFI firmware
	92
214fad55 AB	93	config ARM64_RELOC_TEST
	94	depends on m
	95	tristate "Relocation testing module"
	96
01081f5a	97	source "drivers/hwtracing/coresight/Kconfig"