Replace incorrect matching constraint that caused the error with an alternative
that still has the required constraints on the inline assembly.

This is the error message reported by clang:
arch/mips/include/asm/checksum.h:285:27: error: unsupported inline asm: input with type '__be32' (aka 'unsigned int') matching output with type 'unsigned short'
          "0" (htonl(len)), "1" (htonl(proto)), "r" (sum));
                                 ^~~~~~~~~~~~

The changed code can be compiled successfully by both gcc and clang.
Signed-off-by: NDaniel Sanders <daniel.sanders@imgtec.com>
Signed-off-by: NToma Tabacu <toma.tabacu@imgtec.com>
Suggested-by: NMaciej W. Rozycki <macro@linux-mips.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/9313/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

The following instructions have been removed from MIPS R6

ulw, ulh, swl, lwr, lwl, swr.

However, all of them are used in the MIPS specific checksum implementation.
As a result of which, we will use the generic checksum on MIPS R6
Signed-off-by: NMarkos Chandras <markos.chandras@imgtec.com>

Its implementation is identical to MIPS.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Right now the MIPS <asm/checksum.h> still overrides all functions.  This
will change in the future.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

This isn't only short and easier to read and fully portable but also
shrinks a Malta kernel's by 160 bytes.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

A MIPS specific csum_and_copy_from_user function is necessary because
the generic one from include/net/checksum.h will not work for EVA.
This is because the generic one will link to symbols from lib/checksum.c
which are not EVA aware.
Signed-off-by: NLeonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: NMarkos Chandras <markos.chandras@imgtec.com>

In EVA mode, different instructions need to be used to read/write
from kernel and userland. In non-EVA mode, there is no functional
difference. The current address limit is checked to decide the
type of operation that will be performed.
Signed-off-by: NLeonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: NMarkos Chandras <markos.chandras@imgtec.com>

The 'copy_user' symbol can be used to copy from or to
userland so we will use two different symbols for these
operations. This makes no difference in the existing code,
but when the core is operating in EVA mode, different instructions
need to be used to read and write to userland address space.
The old function has also been renamed to 'copy_kernel' to denote
that it is suitable for copy data to and from kernel space.
Signed-off-by: NMarkos Chandras <markos.chandras@imgtec.com>

Having received another series of whitespace patches I decided to do this
once and for all rather than dealing with this kind of patches trickling
in forever.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

I've traced down an off-by-one TCP checksum calculation error under
the following conditions:

1) The TCP code needs to split a full-sized packet due to a reduced
   MSS (typically due to the addition of TCP options mid-stream like
   SACK).
   _AND_
2) The checksum of the 2nd fragment is larger than the checksum of the
   original packet.  After subtraction this results in a checksum for
   the 1st fragment with bits 16..31 set to 1. (this is ok)
   _AND_
3) The checksum of the 1st fragment's TCP header plus the previously
   32bit checksum of the 1st fragment DOES NOT cause a 32bit overflow
   when added together.  This results in a checksum of the TCP header
   plus TCP data that still has the upper 16 bits as 1's.
   _THEN_
4) The TCP+data checksum is added to the checksum of the pseudo IP
   header with csum_tcpudp_nofold() incorrectly (the bug).
    
The problem is the checksum of the TCP+data is passed to
csum_tcpudp_nofold() as an 32bit unsigned value, however the assembly
code acts on it as if it is a 64bit unsigned value.

This causes an incorrect 32->64bit extension if the sum has bit 31
set.  The resulting checksum is off by one.
    
This problems is data and TCP header dependent due to #2 and #3
above so it doesn't occur on every TCP packet split.
Signed-off-by: NDave Johnson <djohnson+linux-mips@sw.starentnetworks.com>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

The commit 8e3d8433 ([NET]: MIPS
checksum annotations and cleanups) broke 64-bit MIPS.

The problem is the commit replaces some unsigned long with __be32.  On
64bit MIPS, a __be32 (i.e. unsigned int) value is represented as a
sign-extented 32-bit value in a 64-bit argument register.  So the
address 192.168.0.1 (0xc0a80001) is passed as 0xffffffffc0a80001 to
csum_tcpudp_nofold() but the asm code in the function expects
0x00000000c0a80001, therefore it returns a wrong checksum.  Explicit
cast to unsigned long is needed to drop high 32bit.
Signed-off-by: NAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Implement optimized asm version of csum_partial_copy_nocheck,
csum_partial_copy_from_user and csum_and_copy_to_user which can do
calculate and copy in parallel, based on memcpy.S.
Signed-off-by: NAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

* sanitize prototypes, annotate
* kill shift-by-16 in checksum calculations
* htons->shift in l-e checksum calculations
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

to it in an asm() block, and we're running on a system with 64-bit
registers, it is vitally important that we sign extend it correctly before
returning to C.  Otherwise the stray high bits will be preserved into
csum_fold, and on the SB-1 processor, 32-bit arithmetic on a non
sign-extended register will yield surprising results.
    
This caused incorrect checksums in some UDP packets for NFS root.  The
problem was mild when using a 10.0.1.x IP address, but severe when
using 192.168.1.x.
Signed-off-by: NDaniel Jacobowitz <dan@codesourcery.com>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
Signed-off-by: NThiemo Seufer <ths@networkno.de>

Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Start cleaning 32-bit vs. 64-bit configuration.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

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!