Report the exact number of bytes which have not been successfully
copied when an exception occurs, using the running remaining length.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The fixup helper function mechanism for handling user copy fault
handling is not %100 accurrate, and can never be made so.

We are going to transition the code to return the running return
return length, which is always kept track in one or more registers
of each of these routines.

In order to convert them one by one, we have to allow the existing
behavior to continue functioning.

Therefore make all the copy code that wants the fixup helper to be
used return negative one.

After all of the user copy routines have been converted, this logic
and the fixup helpers themselves can be removed completely.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This is based upon a report from Chris Torek and his initial patch.
From Chris's report:

--------------------
This came up in testing kgdb, using the built-in tests -- turn
on CONFIG_KGDB_TESTS, then

    echo V1 > /sys/module/kgdbts/parameters/kgdbts

-- but it would affect using kgdb if you were debugging and looking
at bad pointers.
--------------------

When we get a copy_{from,to}_user() request and the %asi is set to
something other than ASI_AIUS (which is userspace) then we branch off
to a routine called memcpy_user_stub().  It just does a straight
memcpy since we are copying from kernel to kernel in this case.

The logic was that since source and destination are both kernel
pointers we don't need to have exception checks.

But for what probe_kernel_{read,write}() is trying to do, we have to
have the checks, otherwise things like kgdb bad kernel pointer
accesses don't do the right thing.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is an implementation of a suggestion made by Chris Torek:
--------------------
Something else I noticed in passing: the EX and EX_LD/EX_ST macros
scattered throughout the various .S files make a fair bit of .fixup
code, all of which does the same thing.  At the cost of one symbol
in copy_in_user.S, you could just have one common two-instruction
retl-and-mov-1 fixup that they all share.
--------------------

The following is with a defconfig build:

   text	   data	    bss	    dec	    hex	filename
3972767	 344024	 584449	4901240	 4ac978	vmlinux.orig
39688877	 344024	 584449	4897360	 4aba50	vmlinux
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

o Renamed files in sparc64 to <name>_64.S when identical
  to sparc32 files.
o iomap.c were equal for sparc32 and sparc64
o adjusted sparc/Makefile now we have only one lib/
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We must use the "a" (allocate) attribute every time we
emit an entry into the __ex_table section.

For consistency, use "a" instead of #alloc which is some
Solaris compat cruft GNU as provides on Sparc.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!