lib: add weak clz/ctz functions

Some architectures need __c[lt]z[sd]i2() for __builtin_c[lt]z[ll] and
that causes a build failure.  They can be implemented using the
fls()/__ffs() and overridden by linking arch-specific versions may not
be implemented yet.

This is required by "lib: add lz4 compressor module".

Reference: https://lkml.org/lkml/2013/4/18/603

Signed-off-by: Chanho Min <chanho.min@lge.com>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "Darrick J. Wong" <djwong@us.ibm.com>
Cc: Bob Pearson <rpearson@systemfabricworks.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Herbert Xu <herbert@gondor.hengli.com.au>
Cc: Yann Collet <yann.collet.73@gmail.com>
Cc: Kyungsik Lee <kyungsik.lee@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>

Conflicts:
	lib/Makefile

Change-Id: I0126c72d6faf8c0e71f9052bb2706df710650a7e
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
initramfs: read CONFIG_RD_ variables for initramfs compression

When expert configuration option(CONFIG_EXPERT) is enabled, menuconfig
offers a choice of compression algorithm to compress initial ramfs image;
This choice is stored into CONFIG_RD_* variables.  But usr/Makefile uses
earlier INITRAMFS_COMPRESSION_* macros to build initial ramfs file.  Since
none of them is defined, resulting 'initramfs_data.cpio' file remains
un-compressed.

This patch updates the Makefile to use CONFIG_RD_* variables and adds
support for LZ4 compression algorithm.  Also updates the
'gen_initramfs_list.sh' script to check whether a selected compression
command is accessible or not.  And fall-back to default gzip(1)
compression when it is not.

Change-Id: I32aca0c8ccea3f25e65247195ba2d7f576c41fd4
Signed-off-by: P J P <prasad@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
scripts/gen_initramfs_list.sh: fix flags for initramfs LZ4 compression

LZ4 as implemented in the kernel differs from the default method now
used by the reference implementation of LZ4.  Until the in-kernel method
is updated to support the new default, passing the legacy flag (-l) to
the compressor is necessary.  Without this flag the kernel-generated,
LZ4-compressed initramfs is junk.

Kyungsik said:

: It seems that lz4 supports legacy format with the same option as lz4c
: does.  Just looking at the first few bytes of lz4 compressed image, we can
: see whether it is new format or not.
:
: It shows new format magic number without this patch.  New format magic
: number is 0x184d2204.
:
: $ hexdump -C ./initramfs_data.cpio.lz4 |more
: 00000000  04 22 4d 18 64 70 b9 69 (Little Endian)
: ...
:
: Currently kernel supports legacy format only.

Change-Id: I93df5bcf5db593a7f7e6c09b00b29bd7df98cd68
Signed-off-by: Daniel M. Weeks <dan@danweeks.net>
Cc: Michal Marek <mmarek@suse.cz>
Acked-by: Kyungsik Lee <kyungsik.lee@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
kconfig: update compression algorithm info

There have been new compression algorithms added without updating nearby
relevant descriptive text that refers to (a) the number of compression
algorithms and (b) the most recent one.  Fix these inconsistencies.

Change-Id: I8da8c534cb205d1e2fa6888ea5411dc5f816f6e6
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Reported-by: <qasdfgtyuiop@gmail.com>
Cc: Lasse Collin <lasse.collin@tukaani.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Alain Knaff <alain@knaff.lu>
Cc: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
initramfs: remove "compression mode" choice

Commit 9ba4bcb64589 ("initramfs: read CONFIG_RD_ variables for initramfs
compression") removed the users of the various INITRAMFS_COMPRESSION_*
Kconfig symbols.  So since v3.13 the entire "Built-in initramfs
compression mode" choice is a set of knobs connected to nothing.  The
entire choice can safely be removed.

Change-Id: If7412a7183751985a1bfad540ba83dd88866f7dd
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Cc: P J P <ppandit@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
sched/cpuidle: reduce IPI store. Backport upstream 3.16 scheduler updates

Signed-off-by: Paul Reioux <reioux@gmail.com>