The majority of this patch was created by the following script:

***
ASM=arch/sparc/include/asm
mkdir -p $ASM
git mv include/asm-sparc64/ftrace.h $ASM
git rm include/asm-sparc64/*
git mv include/asm-sparc/* $ASM
sed -ie 's/asm-sparc64/asm/g' $ASM/*
sed -ie 's/asm-sparc/asm/g' $ASM/*
***

The rest was an update of the top-level Makefile to use sparc
for header files when sparc64 is being build.
And a small fixlet to pick up the correct unistd.h from
sparc64 code.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Used the following script to copy the files:
cd include
set -e
SPARC64=`ls asm-sparc64`
for FILE in ${SPARC64}; do
	if [ -f asm-sparc/$FILE ]; then
		echo $FILE exist in asm-sparc
	else
		git mv asm-sparc64/$FILE asm-sparc/$FILE
		printf "#include <asm-sparc/$FILE>\n" > asm-sparc64/$FILE
		git add asm-sparc64/$FILE
	fi
done
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Doing a 'flushw' every stack trace capture creates so much overhead
that it makes lockdep next to unusable.

We only care about the frame pointer chain and the function caller
program counters, so flush those by hand to the stack frame.

This is significantly more efficient than a 'flushw' because:

1) We only save 16 bytes per active register window to the stack.

2) This doesn't push the entire register window context of the current
   call chain out of the cpu, forcing register window fill traps as we
   return back down.

Note that we can't use 'restore' and 'save' instructions to move
around the register windows because that wouldn't work on Niagara
processors.  They optimize 'save' into a new register window by
simply clearing out the registers instead of pulling them in from
the on-chip register window backing store.

Based upon a report by Tom Callaway.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>