Aligning the .bss section makes it trivial to use large operation
sizes for moving the initialized sections and clearing the .bss.
The alignment chosen (L1 cache) is somewhat arbitrary, but should be
large enough to avoid all known performance traps and small enough to
not cause troubles.

[ Impact: trivial performance enhancement, future patch prep	]
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Jesper reported that he saw following build issue:

 > ld:arch/x86/boot/compressed/vmlinux.lds:9: syntax error
 > make[2]: *** [arch/x86/boot/compressed/vmlinux] Error 1
 > make[1]: *** [arch/x86/boot/compressed/vmlinux] Error 2
 > make: *** [bzImage] Error 2

CPP defines the symbol "i386" to "1".
Undefine this to fix it.

[ Impact: build fix with certain tool chains ]
Reported-by: NJesper Dangaard Brouer <jdb@comx.dk>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <alpine.LFD.2.00.0904260958190.3101@localhost.localdomain>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Look at the:

	diff -u arch/x86/boot/compressed/vmlinux_*.lds

output and realize that they're basially exactly the same except for
trivial naming differences, and the fact that the 64-bit version has a
"pgtable" thing.

So unify them.

There's some trivial cleanup there (make the output format a Kconfig thing
rather than doing #ifdef's for it, and unify both 32-bit and 64-bit BSS
end to "_ebss", where 32-bit used to use the traditional "_end"), but
other than that it's really very mindless and straigt conversion.

For example, I think we should aim to remove "startup_32" vs "startup_64",
and just call it "startup", and get rid of one more difference. I didn't
do that.

Also, notice the comment in the unified vmlinux.lds.S talks about
"head_64" and "startup_32" which is an odd and incorrect mix, but that was
actually what the old 64-bit only lds file had, so the confusion isn't
new, and now that mixing is arguably more accurate thanks to the
vmlinux.lds.S file being shared between the two cases ;)

[ Impact: cleanup, unification ]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Acked-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

cleanup: change the _end in compressed vmlinux_64.lds.

also change _heap to _ebss that is not needed.
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

for bzImage, the vmlinux_64.lds still have s32 bit code, and startup_32
should be 0. fix the comment.
Signed-off-by: NYinghai Lu <yinghai.lu@sun.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

vmlinux_64 and vmlinux_32.scr are now identical

size shows an expected movement from .text to .rodata and 4 extra bytes
of padding.
Signed-off-by: NIan Campbell <ijc@hellion.org.uk>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

size reports no change in arch/x86/boot/compressed/vmlinux.
Signed-off-by: NIan Campbell <ijc@hellion.org.uk>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This patch modifies the x86_64 kernel so that it can be loaded and run
at any 2M aligned address, below 512G.  The technique used is to
compile the decompressor with -fPIC and modify it so the decompressor
is fully relocatable.  For the main kernel the page tables are
modified so the kernel remains at the same virtual address.  In
addition a variable phys_base is kept that holds the physical address
the kernel is loaded at.  __pa_symbol is modified to add that when
we take the address of a kernel symbol.

When loaded with a normal bootloader the decompressor will decompress
the kernel to 2M and it will run there.  This both ensures the
relocation code is always working, and makes it easier to use 2M
pages for the kernel and the cpu.

AK: changed to not make RELOCATABLE default in Kconfig
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>

This patch modifies the i386 kernel so that if CONFIG_RELOCATABLE is
selected it will be able to be loaded at any 4K aligned address below
1G.  The technique used is to compile the decompressor with -fPIC and
modify it so the decompressor is fully relocatable.  For the main
kernel relocations are generated.  Resulting in a kernel that is relocatable
with no runtime overhead and no need to modify the source code.

A reserved 32bit word in the parameters has been assigned
to serve as a stack so we figure out where are running.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>