[linux-block.git] / usr / Kconfig

#
# Configuration for initramfs
#

config INITRAMFS_SOURCE
	string "Initramfs source file(s)"
	default ""
	help
	  This can be either a single cpio archive with a .cpio suffix or a
	  space-separated list of directories and files for building the
	  initramfs image.  A cpio archive should contain a filesystem archive
	  to be used as an initramfs image.  Directories should contain a
	  filesystem layout to be included in the initramfs image.  Files
	  should contain entries according to the format described by the
	  "usr/gen_init_cpio" program in the kernel tree.

	  When multiple directories and files are specified then the
	  initramfs image will be the aggregate of all of them.

	  See <file:Documentation/early-userspace/README> for more details.

	  If you are not sure, leave it blank.

config INITRAMFS_FORCE
	bool "Ignore the initramfs passed by the bootloader"
	depends on CMDLINE_EXTEND || CMDLINE_FORCE
	help
	  This option causes the kernel to ignore the initramfs image
	  (or initrd image) passed to it by the bootloader. This is
	  analogous to CMDLINE_FORCE, which is found on some architectures,
	  and is useful if you cannot or don't want to change the image
	  your bootloader passes to the kernel.

config INITRAMFS_ROOT_UID
	int "User ID to map to 0 (user root)"
	depends on INITRAMFS_SOURCE!=""
	default "0"
	help
	  This setting is only meaningful if the INITRAMFS_SOURCE is
	  contains a directory.  Setting this user ID (UID) to something
	  other than "0" will cause all files owned by that UID to be
	  owned by user root in the initial ramdisk image.

	  If you are not sure, leave it set to "0".

config INITRAMFS_ROOT_GID
	int "Group ID to map to 0 (group root)"
	depends on INITRAMFS_SOURCE!=""
	default "0"
	help
	  This setting is only meaningful if the INITRAMFS_SOURCE is
	  contains a directory.  Setting this group ID (GID) to something
	  other than "0" will cause all files owned by that GID to be
	  owned by group root in the initial ramdisk image.

	  If you are not sure, leave it set to "0".

config RD_GZIP
	bool "Support initial ramdisks compressed using gzip"
	depends on BLK_DEV_INITRD
	default y
	select DECOMPRESS_GZIP
	help
	  Support loading of a gzip encoded initial ramdisk or cpio buffer.
	  If unsure, say Y.

config RD_BZIP2
	bool "Support initial ramdisks compressed using bzip2"
	default y
	depends on BLK_DEV_INITRD
	select DECOMPRESS_BZIP2
	help
	  Support loading of a bzip2 encoded initial ramdisk or cpio buffer
	  If unsure, say N.

config RD_LZMA
	bool "Support initial ramdisks compressed using LZMA"
	default y
	depends on BLK_DEV_INITRD
	select DECOMPRESS_LZMA
	help
	  Support loading of a LZMA encoded initial ramdisk or cpio buffer
	  If unsure, say N.

config RD_XZ
	bool "Support initial ramdisks compressed using XZ"
	depends on BLK_DEV_INITRD
	default y
	select DECOMPRESS_XZ
	help
	  Support loading of a XZ encoded initial ramdisk or cpio buffer.
	  If unsure, say N.

config RD_LZO
	bool "Support initial ramdisks compressed using LZO"
	default y
	depends on BLK_DEV_INITRD
	select DECOMPRESS_LZO
	help
	  Support loading of a LZO encoded initial ramdisk or cpio buffer
	  If unsure, say N.

config RD_LZ4
	bool "Support initial ramdisks compressed using LZ4"
	default y
	depends on BLK_DEV_INITRD
	select DECOMPRESS_LZ4
	help
	  Support loading of a LZ4 encoded initial ramdisk or cpio buffer
	  If unsure, say N.

choice
	prompt "Built-in initramfs compression mode"
	depends on INITRAMFS_SOURCE!=""
	optional
	help
	  This option allows you to decide by which algorithm the builtin
	  initramfs will be compressed.  Several compression algorithms are
	  available, which differ in efficiency, compression and
	  decompression speed.  Compression speed is only relevant
	  when building a kernel.  Decompression speed is relevant at
	  each boot. Also the memory usage during decompression may become
	  relevant on memory constrained systems. This is usually based on the
	  dictionary size of the algorithm with algorithms like XZ and LZMA
	  featuring large dictionary sizes.

	  High compression options are mostly useful for users who are
	  low on RAM, since it reduces the memory consumption during
	  boot.

	  Keep in mind that your build system needs to provide the appropriate
	  compression tool to compress the generated initram cpio file for
	  embedding.

	  If in doubt, select 'None'

config INITRAMFS_COMPRESSION_NONE
	bool "None"
	help
	  Do not compress the built-in initramfs at all. This may sound wasteful
	  in space, but, you should be aware that the built-in initramfs will be
	  compressed at a later stage anyways along with the rest of the kernel,
	  on those architectures that support this. However, not compressing the
	  initramfs may lead to slightly higher memory consumption during a
	  short time at boot, while both the cpio image and the unpacked
	  filesystem image will be present in memory simultaneously

config INITRAMFS_COMPRESSION_GZIP
	bool "Gzip"
	depends on RD_GZIP
	help
	  Use the old and well tested gzip compression algorithm. Gzip provides
	  a good balance between compression ratio and decompression speed and
	  has a reasonable compression speed. It is also more likely to be
	  supported by your build system as the gzip tool is present by default
	  on most distros.

config INITRAMFS_COMPRESSION_BZIP2
	bool "Bzip2"
	depends on RD_BZIP2
	help
	  It's compression ratio and speed is intermediate. Decompression speed
	  is slowest among the choices. The initramfs size is about 10% smaller
	  with bzip2, in comparison to gzip. Bzip2 uses a large amount of
	  memory. For modern kernels you will need at least 8MB RAM or more for
	  booting.

	  If you choose this, keep in mind that you need to have the bzip2 tool
	  available to be able to compress the initram.

config INITRAMFS_COMPRESSION_LZMA
	bool "LZMA"
	depends on RD_LZMA
	help
	  This algorithm's compression ratio is best but has a large dictionary
	  size which might cause issues in memory constrained systems.
	  Decompression speed is between the other choices. Compression is
	  slowest. The initramfs size is about 33% smaller with LZMA in
	  comparison to gzip.

	  If you choose this, keep in mind that you may need to install the xz
	  or lzma tools to be able to compress the initram.

config INITRAMFS_COMPRESSION_XZ
	bool "XZ"
	depends on RD_XZ
	help
	  XZ uses the LZMA2 algorithm and has a large dictionary which may cause
	  problems on memory constrained systems. The initramfs size is about
	  30% smaller with XZ in comparison to gzip. Decompression speed is
	  better than that of bzip2 but worse than gzip and LZO. Compression is
	  slow.

	  If you choose this, keep in mind that you may need to install the xz
	  tool to be able to compress the initram.

config INITRAMFS_COMPRESSION_LZO
	bool "LZO"
	depends on RD_LZO
	help
	  It's compression ratio is the second poorest amongst the choices. The
	  kernel size is about 10% bigger than gzip. Despite that, it's
	  decompression speed is the second fastest and it's compression speed
	  is quite fast too.

	  If you choose this, keep in mind that you may need to install the lzop
	  tool to be able to compress the initram.

config INITRAMFS_COMPRESSION_LZ4
	bool "LZ4"
	depends on RD_LZ4
	help
	  It's compression ratio is the poorest amongst the choices. The kernel
	  size is about 15% bigger than gzip; however its decompression speed
	  is the fastest.

	  If you choose this, keep in mind that most distros don't provide lz4
	  by default which could cause a build failure.

endchoice

config INITRAMFS_COMPRESSION
	depends on INITRAMFS_SOURCE!=""
	string
	default ""      if INITRAMFS_COMPRESSION_NONE
	default ".gz"   if INITRAMFS_COMPRESSION_GZIP
	default ".bz2"  if INITRAMFS_COMPRESSION_BZIP2
	default ".lzma" if INITRAMFS_COMPRESSION_LZMA
	default ".xz"   if INITRAMFS_COMPRESSION_XZ
	default ".lzo"  if INITRAMFS_COMPRESSION_LZO
	default ".lz4"  if INITRAMFS_COMPRESSION_LZ4
	default ".gz"   if RD_GZIP
	default ".lz4"  if RD_LZ4
	default ".lzo"  if RD_LZO
	default ".xz"   if RD_XZ
	default ".lzma" if RD_LZMA
	default ".bz2"  if RD_BZIP2
	default ""
Commit	Line	Data
dbec4866 SR	1	#
	2	# Configuration for initramfs
	3	#
	4
	5	config INITRAMFS_SOURCE
	6	string "Initramfs source file(s)"
	7	default ""
	8	help
	9	This can be either a single cpio archive with a .cpio suffix or a
	10	space-separated list of directories and files for building the
	11	initramfs image. A cpio archive should contain a filesystem archive
	12	to be used as an initramfs image. Directories should contain a
	13	filesystem layout to be included in the initramfs image. Files
	14	should contain entries according to the format described by the
	15	"usr/gen_init_cpio" program in the kernel tree.
	16
	17	When multiple directories and files are specified then the
	18	initramfs image will be the aggregate of all of them.
	19
0979f378	20	See <file:Documentation/early-userspace/README> for more details.
dbec4866 SR	21
	22	If you are not sure, leave it blank.
	23
cff75e0b DT	24	config INITRAMFS_FORCE
	25	bool "Ignore the initramfs passed by the bootloader"
	26	depends on CMDLINE_EXTEND \|\| CMDLINE_FORCE
	27	help
	28	This option causes the kernel to ignore the initramfs image
	29	(or initrd image) passed to it by the bootloader. This is
	30	analogous to CMDLINE_FORCE, which is found on some architectures,
	31	and is useful if you cannot or don't want to change the image
	32	your bootloader passes to the kernel.
	33
dbec4866 SR	34	config INITRAMFS_ROOT_UID
	35	int "User ID to map to 0 (user root)"
	36	depends on INITRAMFS_SOURCE!=""
	37	default "0"
	38	help
	39	This setting is only meaningful if the INITRAMFS_SOURCE is
	40	contains a directory. Setting this user ID (UID) to something
	41	other than "0" will cause all files owned by that UID to be
	42	owned by user root in the initial ramdisk image.
	43
	44	If you are not sure, leave it set to "0".
	45
	46	config INITRAMFS_ROOT_GID
	47	int "Group ID to map to 0 (group root)"
	48	depends on INITRAMFS_SOURCE!=""
	49	default "0"
	50	help
	51	This setting is only meaningful if the INITRAMFS_SOURCE is
	52	contains a directory. Setting this group ID (GID) to something
	53	other than "0" will cause all files owned by that GID to be
	54	owned by group root in the initial ramdisk image.
	55
	56	If you are not sure, leave it set to "0".
fb9a4ca9 PA	57
fb9a4ca9 PA	58	config RD_GZIP
ec72c666	59	bool "Support initial ramdisks compressed using gzip"
73d8a12f	60	depends on BLK_DEV_INITRD
ec72c666	61	default y
fb9a4ca9 PA	62	select DECOMPRESS_GZIP
	63	help
	64	Support loading of a gzip encoded initial ramdisk or cpio buffer.
	65	If unsure, say Y.
	66
	67	config RD_BZIP2
ec72c666 AK	68	bool "Support initial ramdisks compressed using bzip2"
ec72c666 AK	69	default y
73d8a12f	70	depends on BLK_DEV_INITRD
fb9a4ca9 PA	71	select DECOMPRESS_BZIP2
	72	help
	73	Support loading of a bzip2 encoded initial ramdisk or cpio buffer
	74	If unsure, say N.
	75
	76	config RD_LZMA
ec72c666 AK	77	bool "Support initial ramdisks compressed using LZMA"
ec72c666 AK	78	default y
73d8a12f	79	depends on BLK_DEV_INITRD
fb9a4ca9 PA	80	select DECOMPRESS_LZMA
fb9a4ca9 PA	81	help
55d1d26f	82	Support loading of a LZMA encoded initial ramdisk or cpio buffer
fb9a4ca9	83	If unsure, say N.
ab76f3d7	84
3ebe1243	85	config RD_XZ
ec72c666	86	bool "Support initial ramdisks compressed using XZ"
3ebe1243	87	depends on BLK_DEV_INITRD
ec72c666	88	default y
3ebe1243 LC	89	select DECOMPRESS_XZ
	90	help
	91	Support loading of a XZ encoded initial ramdisk or cpio buffer.
	92	If unsure, say N.
	93
cacb246f	94	config RD_LZO
ec72c666 AK	95	bool "Support initial ramdisks compressed using LZO"
ec72c666 AK	96	default y
cacb246f AT	97	depends on BLK_DEV_INITRD
	98	select DECOMPRESS_LZO
	99	help
	100	Support loading of a LZO encoded initial ramdisk or cpio buffer
	101	If unsure, say N.
	102
e76e1fdf	103	config RD_LZ4
ec72c666 AK	104	bool "Support initial ramdisks compressed using LZ4"
ec72c666 AK	105	default y
e76e1fdf KL	106	depends on BLK_DEV_INITRD
	107	select DECOMPRESS_LZ4
	108	help
	109	Support loading of a LZ4 encoded initial ramdisk or cpio buffer
	110	If unsure, say N.
35e669e1	111
db2aa7fd FBIR	112	choice
	113	prompt "Built-in initramfs compression mode"
	114	depends on INITRAMFS_SOURCE!=""
	115	optional
	116	help
	117	This option allows you to decide by which algorithm the builtin
	118	initramfs will be compressed. Several compression algorithms are
	119	available, which differ in efficiency, compression and
	120	decompression speed. Compression speed is only relevant
	121	when building a kernel. Decompression speed is relevant at
	122	each boot. Also the memory usage during decompression may become
	123	relevant on memory constrained systems. This is usually based on the
	124	dictionary size of the algorithm with algorithms like XZ and LZMA
	125	featuring large dictionary sizes.
	126
	127	High compression options are mostly useful for users who are
	128	low on RAM, since it reduces the memory consumption during
	129	boot.
	130
	131	Keep in mind that your build system needs to provide the appropriate
	132	compression tool to compress the generated initram cpio file for
	133	embedding.
	134
	135	If in doubt, select 'None'
	136
	137	config INITRAMFS_COMPRESSION_NONE
	138	bool "None"
	139	help
	140	Do not compress the built-in initramfs at all. This may sound wasteful
	141	in space, but, you should be aware that the built-in initramfs will be
	142	compressed at a later stage anyways along with the rest of the kernel,
	143	on those architectures that support this. However, not compressing the
	144	initramfs may lead to slightly higher memory consumption during a
	145	short time at boot, while both the cpio image and the unpacked
	146	filesystem image will be present in memory simultaneously
	147
	148	config INITRAMFS_COMPRESSION_GZIP
	149	bool "Gzip"
	150	depends on RD_GZIP
	151	help
	152	Use the old and well tested gzip compression algorithm. Gzip provides
	153	a good balance between compression ratio and decompression speed and
	154	has a reasonable compression speed. It is also more likely to be
	155	supported by your build system as the gzip tool is present by default
	156	on most distros.
	157
	158	config INITRAMFS_COMPRESSION_BZIP2
	159	bool "Bzip2"
	160	depends on RD_BZIP2
	161	help
	162	It's compression ratio and speed is intermediate. Decompression speed
	163	is slowest among the choices. The initramfs size is about 10% smaller
	164	with bzip2, in comparison to gzip. Bzip2 uses a large amount of
	165	memory. For modern kernels you will need at least 8MB RAM or more for
	166	booting.
	167
	168	If you choose this, keep in mind that you need to have the bzip2 tool
	169	available to be able to compress the initram.
	170
	171	config INITRAMFS_COMPRESSION_LZMA
	172	bool "LZMA"
	173	depends on RD_LZMA
	174	help
	175	This algorithm's compression ratio is best but has a large dictionary
176	size which might cause issues in memory constrained systems.
177	Decompression speed is between the other choices. Compression is
178	slowest. The initramfs size is about 33% smaller with LZMA in
179	comparison to gzip.
180
181	If you choose this, keep in mind that you may need to install the xz
182	or lzma tools to be able to compress the initram.
183
184	config INITRAMFS_COMPRESSION_XZ
185	bool "XZ"
186	depends on RD_XZ
187	help
188	XZ uses the LZMA2 algorithm and has a large dictionary which may cause
189	problems on memory constrained systems. The initramfs size is about
190	30% smaller with XZ in comparison to gzip. Decompression speed is
191	better than that of bzip2 but worse than gzip and LZO. Compression is
192	slow.
193
194	If you choose this, keep in mind that you may need to install the xz
195	tool to be able to compress the initram.
196
197	config INITRAMFS_COMPRESSION_LZO
198	bool "LZO"
199	depends on RD_LZO
200	help
201	It's compression ratio is the second poorest amongst the choices. The
202	kernel size is about 10% bigger than gzip. Despite that, it's
203	decompression speed is the second fastest and it's compression speed
204	is quite fast too.
205
206	If you choose this, keep in mind that you may need to install the lzop
207	tool to be able to compress the initram.
208
209	config INITRAMFS_COMPRESSION_LZ4
210	bool "LZ4"
211	depends on RD_LZ4
212	help
213	It's compression ratio is the poorest amongst the choices. The kernel
214	size is about 15% bigger than gzip; however its decompression speed
215	is the fastest.
216
217	If you choose this, keep in mind that most distros don't provide lz4
218	by default which could cause a build failure.
219
220	endchoice
221
35e669e1	222	config INITRAMFS_COMPRESSION
57ddfdaa	223	depends on INITRAMFS_SOURCE!=""
35e669e1	224	string
db2aa7fd FBIR	225	default "" if INITRAMFS_COMPRESSION_NONE
	226	default ".gz" if INITRAMFS_COMPRESSION_GZIP
	227	default ".bz2" if INITRAMFS_COMPRESSION_BZIP2
	228	default ".lzma" if INITRAMFS_COMPRESSION_LZMA
	229	default ".xz" if INITRAMFS_COMPRESSION_XZ
	230	default ".lzo" if INITRAMFS_COMPRESSION_LZO
	231	default ".lz4" if INITRAMFS_COMPRESSION_LZ4
35e669e1 FBIR	232	default ".gz" if RD_GZIP
	233	default ".lz4" if RD_LZ4
	234	default ".lzo" if RD_LZO
	235	default ".xz" if RD_XZ
	236	default ".lzma" if RD_LZMA
	237	default ".bz2" if RD_BZIP2
	238	default ""