The meaning of CONFIG_EMBEDDED has long since been obsoleted; the option
is used to configure any non-standard kernel with a much larger scope than
only small devices.

This patch renames the option to CONFIG_EXPERT in init/Kconfig and fixes
references to the option throughout the kernel.  A new CONFIG_EMBEDDED
option is added that automatically selects CONFIG_EXPERT when enabled and
can be used in the future to isolate options that should only be
considered for embedded systems (RISC architectures, SLOB, etc).

Calling the option "EXPERT" more accurately represents its intention: only
expert users who understand the impact of the configuration changes they
are making should enable it.
Reviewed-by: NIngo Molnar <mingo@elte.hu>
Acked-by: NDavid Woodhouse <david.woodhouse@intel.com>
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Cc: Greg KH <gregkh@suse.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Robin Holt <holt@sgi.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This implements the API defined in <linux/decompress/generic.h> which is
used for kernel, initramfs, and initrd decompression.  This patch together
with the first patch is enough for XZ-compressed initramfs and initrd;
XZ-compressed kernel will need arch-specific changes.

The buffering requirements described in decompress_unxz.c are stricter
than with gzip, so the relevant changes should be done to the
arch-specific code when adding support for XZ-compressed kernel.
Similarly, the heap size in arch-specific pre-boot code may need to be
increased (30 KiB is enough).

The XZ decompressor needs memmove(), memeq() (memcmp() == 0), and
memzero() (memset(ptr, 0, size)), which aren't available in all
arch-specific pre-boot environments.  I'm including simple versions in
decompress_unxz.c, but a cleaner solution would naturally be nicer.
Signed-off-by: NLasse Collin <lasse.collin@tukaani.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alain Knaff <alain@knaff.lu>
Cc: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Cc: Phillip Lougher <phillip@lougher.demon.co.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Deleted a word which apeared twice.
Signed-off-by: NStephan Sperber <sperberstephan@googlemail.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Signed-off-by: NAlbin Tonnerre <albin.tonnerre@free-electrons.com>
Tested-by: NWu Zhangjin <wuzhangjin@gmail.com>
Acked-by: N"H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Tested-by: NRussell King <rmk@arm.linux.org.uk>
Acked-by: NRussell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Impact: quiet Kconfig warning

It appears that Kconfig simply has no way to provide defaults for
entries that exist inside a conditionalized choice block.
Fortunately, it turns out we don't actually ever use
CONFIG_INITRAMFS_COMPRESSION_NONE, so we can just drop it for
everything outside the choice block.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: Kconfig noise reduction, documentation

The default initramfs is so small that it makes no sense to worry
about the additional memory taken by not double-compressing it.
Therefore, don't bug the user with it.

Also, improve the description of the option, which was downright
incorrect.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: message formatting

Consistently spell LZMA in all capitals, since it (unlike gzip or
bzip2) is an acronym.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: Kconfig clarification

Make it clear that the CONFIG_RD_* options are about what formats are
supported, not about what formats are actually being used.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: reduce Kconfig noise

Move the options that control possible initramfs/initrd compressions
underneath CONFIG_EMBEDDED.  The only impact of leaving these options
set to y is additional code in the init section of the kernel; there
is no reason to burden non-embedded users with these options.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: Avoids silent environment dependency

Make builtin initramfs compression an explicit configurable.  The
previous version would pick a compression based on the binaries which
were installed on the system, which could lead to unexpected results.
It is now explicitly configured, and not having the appropriate
binaries installed on the build host is simply an error.
Signed-off-by: NAlain Knaff <alain@knaff.lu>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Impact: Partial resolution of build failure

Move the initrd/initramfs configuration options from
drivers/block/Kconfig to usr/Kconfig, since they do not and should not
depend on CONFIG_BLK_DEV.  This fixes builds when CONFIG_BLK_DEV=n.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Signed-off-by: Alexander E. Patrakov
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Move initramfs options from Device Drivers | Block Drivers to General Setup
This is a more natural place for this option.

Furthermore separate out intramfs options to usr/Kconfig
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>