ARM: zImage: don't hard code the stack size twice

Acked-by: Eric Miao <eric.miao@canonical.com>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
ARM: zImage: some comments for __armv3_mpu_cache_on

__armv3_mpu_cache_on seems broken.  As there is noone around who knows
about these machines just keep the code as is but point out the strange
things.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
ARM: zImage: __armv3_mpu_cache_flush: respect should-be-zero specification

Probably the register content for cache operations is "don't care" in
practice, but as r1 is explicitly zeroed, use that one.

Acked-by: Eric Miao <eric.miao@canonical.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
ARM: zImage: fix comments for cache_on, cache_off and cache_clean_flush

This adds missing registers to the list of corrupted registers and
removes a wrong comment about r9 on entry

While at it the formatting of the comment to cache_off is changed to
resemble the other two.

Acked-by: Eric Miao <eric.miao@canonical.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
ARM: zImage: annotate debug functions about corrupted registers

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
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>