ARM: support XZ compressed kernels

Conflicts:

	lib/xz/xz_dec_stream.c
ARM: zImage: don't define unused symbol initrd_phys

The only user of initrd_phys is arch/arm/boot/bootp/init.S which still
gets the value passed to.

Acked-by: Eric Miao <eric.miao@canonical.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
ARM: Remove unused PARAMS_PHYS from arch/arm/boot/compressed

The only reference in arch/arm/boot/compressed to PARAMS_PHYS is
params() in head.S, which can be directly converted to the exact
address as specified by arch/arm/mach-rpc/Makefile.boot.

Signed-off-by: Eric Miao <eric.miao@canonical.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
ARM: Auto calculate ZRELADDR and provide option for exceptions

As long as the zImage is placed within the 128MB range from the start of
memory, ZRELADDR (Address where the decompressed kernel will be placed,
usually == PHYS_OFFSET + TEXT_OFFSET) can be determined at run-time by
masking PC with 0xf80000000.

Running through all the Makefile.boot, all those zreladdr-y
addresses == 0x[0-f][08]00_0000 + TEXT_OFFSET can be determined at
run-time.

Option CONFIG_AUTO_ZRELADDR and CONFIG_ZRELADDR are introduced,
CONFIG_ZRELADDR _must_ be explicitly specified if:

- ((zreladdr-y - TEXT_OFFSET) & ~0xf8000000) != 0, which means
  masking PC with 0xf8000000 will result in an incorrect address.
  Currently this is only a problem on u300.

- or the assumption of the zImage being loaded by the bootloader within
  the first 128MB of RAM is incorrect

- or when ZBOOT_ROM is used, where the above assumption is usually wrong.

[ukleinek: changed mask from 0xf0000000 to 0xf8000000 for mx1 and shark
+ some review fixes from the mailing list]

Original-Idea-and-Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Eric Miao <eric.miao@canonical.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
ARM: Partially revert "Auto calculate ZRELADDR and provide option for exceptions"

Partially revert e69edc7, which introduced automatic zreladdr
support.  The change in the way the manual definition is defined
seems to be error and conflict prone.  Go back to the original way
we were handling this for the time being, while keeping the automatic
zreladdr facility.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: Fix build error when using KCONFIG_CONFIG

Jonathan Cameron reports that when using the environment
variable KCONFIG_CONFIG, he encounters this error:

make[2]: *** No rule to make target `.config', needed by `arch/arm/boot/compressed/vmlinux.lds'

Reported-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 6746/1: remove the 4x expansion presumption while decompressing the kernel

We currently presume a 4x expansion to guess the decompressed kernel size
in order to determine if the decompressed kernel is in conflict with
the location where zImage is loaded.  This guess may cause many issues
by overestimating the final kernel image size:

- This may force a needless relocation if the location of zImage was
  fine, wasting some precious microseconds of boot time.

- The relocation may be located way too far, possibly overwriting the
  initrd image in RAM.

- If the kernel image includes a large already-compressed initramfs image
  then the problem is even more exacerbated.

And if by some strange means the 4x guess is too low then we may overwrite
ourselves with the decompressed image.

So let's use the exact decompressed kernel image size instead.  For that
we need to rely on the stat command, but this is hardly a new build
dependency as the kernel already depends on many external commands
to be built provided by the coreutils package where stat is found.

Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 6778/1: compressed/head.S: make LDFLAGS_vmlinux into a recursively expanded variable

The simply expanded variable may be evaluated before the target file for
the stat command is up to date or even exists.  Switching to a recursively
expanded variable move the execution of the stat command to the location
where LDFLAGS_vmlinux is actually used, fixing the dependency issue
introduced by patch #6746/1.

Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
arm: change to new flag variables

Replace EXTRA_CFLAGS with ccflags-y and EXTRA_AFLAGS with asflags-y.

Signed-off-by: matt mooney <mfm@muteddisk.com>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
ARM: avoid marking decompressor .stack section as having contents

The .stack section doesn't contain any contents, and doesn't require
initialization either.  Rather than marking the output section with
'NOLOAD' but still having it exist in the object files, mark it with
%nobits which avoids the assembler marking the section with 'CONTENTS'.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>