powerpc/math-emu: Update macros from GCC

The add_ssaaaa, sub_ddmmss, umul_ppmm and udiv_qrnnd macros originate
from GCC's longlong.h which in turn was copied from GMP's longlong.h a
few decades ago.

This was found when compiling with clang:

arch/powerpc/math-emu/fnmsub.c:46:2: error: invalid use of a cast in a
inline asm context requiring an l-value: remove the cast or build with
-fheinous-gnu-extensions
FP_ADD_D(R, T, B);
^~~~~~~~~~~~~~~~~
...

./arch/powerpc/include/asm/sfp-machine.h:283:27: note: expanded from
macro 'sub_ddmmss'
: "=r" ((USItype)(sh)), \
~~~~~~~~~~^~~

Segher points out: this was fixed in GCC over 16 years ago
( https://gcc.gnu.org/r56600 ), and in GMP (where it comes from)
presumably before that.

Update the add_ssaaaa, sub_ddmmss, umul_ppmm and udiv_qrnnd macros to
the latest GCC version in order to git rid of the invalid casts. These
were taken as-is from GCC's longlong in order to make future syncs
obvious. Other parts of sfp-machine.h were left as-is as the file
contains more features than present in longlong.h.

Link: https://github.com/ClangBuiltLinux/linux/issues/260
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc: Put FP/VSX and VR state into structures

This creates new 'thread_fp_state' and 'thread_vr_state' structures
to store FP/VSX state (including FPSCR) and Altivec/VSX state
(including VSCR), and uses them in the thread_struct. In the
thread_fp_state, the FPRs and VSRs are represented as u64 rather
than double, since we rarely perform floating-point computations
on the values, and this will enable the structures to be used
in KVM code as well. Similarly FPSCR is now a u64 rather than
a structure of two 32-bit values.

This takes the offsets out of the macros such as SAVE_32FPRS,
REST_32FPRS, etc. This enables the same macros to be used for normal
and transactional state, enabling us to delete the transactional
versions of the macros. This also removes the unused do_load_up_fpu
and do_load_up_altivec, which were in fact buggy since they didn't
create large enough stack frames to account for the fact that
load_up_fpu and load_up_altivec are not designed to be called from C
and assume that their caller's stack frame is an interrupt frame.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Revert "endian: #define __BYTE_ORDER"

This reverts commit b3b77c8caef1750ebeea1054e39e358550ea9f55, which was
also totally broken (see commit 0d2daf5cc858 that reverted the crc32
version of it). As reported by Stephen Rothwell, it causes problems on
big-endian machines:

> In file included from fs/jfs/jfs_types.h:33,
> from fs/jfs/jfs_incore.h:26,
> from fs/jfs/file.c:22:
> fs/jfs/endian24.h:36:101: warning: "__LITTLE_ENDIAN" is not defined

The kernel has never had that crazy "__BYTE_ORDER == __LITTLE_ENDIAN"
model. It's not how we do things, and it isn't how we _should_ do
things. So don't go there.

Requested-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

endian: #define __BYTE_ORDER

Linux does not define __BYTE_ORDER in its endian header files which makes
some header files bend backwards to get at the current endian. Lets
#define __BYTE_ORDER in big_endian.h/litte_endian.h to make it easier for
header files that are used in user space too.

In userspace the convention is that

1. _both_ __LITTLE_ENDIAN and __BIG_ENDIAN are defined,
2. you have to test for e.g. __BYTE_ORDER == __BIG_ENDIAN.

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

powerpc/math-emu: Change types to work on ppc64

While normally we don't use the math emulation code on ppc64 it can be
useful for doing things like emulating the embedded FP instructions.

Since performance isn't critical in this scenario its easier to keep
the sizes of the various math-emu the same as on ppc32.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

powerpc: Add SPE/EFP math emulation for E500v1/v2 processors.

This patch add the handlers of SPE/EFP exceptions.
The code is used to emulate float point arithmetic,
when MSR(SPE) is enabled and receive EFP data interrupt or EFP round interrupt.

This patch has no conflict with or dependence on FP math-emu.

The code has been tested by TestFloat.

Now the code doesn't support SPE/EFP instructions emulation
(it won't be called when receive program interrupt),
but it could be easily added.

Signed-off-by: Liu Yu <yu.liu@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

powerpc/math-emu: Adopt new version of _FP_CHOOSENAN

Move to using the same macro definition for _FP_CHOOSENAN as s390,
sh, sparc32/64. The original author didn't understand this and
matched what sparc64 was doing and they have updated to this definition.

Signed-off-by: Liu Yu <yu.liu@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

powerpc/math-emu: Fix single float point division bug

PowerPC float point division emulation is derived from gcc.
I reported this problem on gcc maillist and got this reply:
http://gcc.gnu.org/ml/gcc/2008-03/msg00543.html

Since UDIV_NEEDS_NORMALIZATION is not used by kernel, we should use
_FP_DIV_MEAT_1_udiv_norm to make sure the single float point
is normalized before udiv_qrnnd.

Signed-off-by: Liu Yu <yu.liu@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

powerpc/math-emu: Use kernel generic math-emu code

The math emulation code is centered around a set of generic macros that
provide the core of the emulation that are shared by the various
architectures and other projects (like glibc). Each arch implements its
own sfp-machine.h to specific various arch specific details.

For historic reasons that are now lost the powerpc math-emu code had
its own version of the common headers. This moves us to using the
kernel generic version and thus getting fixes when those are updated.

Also cleaned up exception/error reporting from the FP emulation functions.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>