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: NKumar Gala <galak@kernel.crashing.org>

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

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

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

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: NKumar Gala <galak@kernel.crashing.org>

Towards the goal of having arch/powerpc not build anything over in arch/ppc
move math-emu over.  Also, killed some references to arch/ppc/ in the
arch/powerpc Makefile which should belong in drivers/ when the particular
sub-arch's move over to arch/powerpc.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

The recent merge of fpu.S broken the handling of fpscr for
ARCH=powerpc and CONFIG_PPC64=y.  FP registers could be corrupted,
leading to strange random application crashes.

The confusion arises, because the thread_struct has (and requires) a
64-bit area to save the fpscr, because we use load/store double
instructions to get it in to/out of the FPU.  However, only the low
32-bits are actually used, so we want to treat it as a 32-bit quantity
when manipulating its bits to avoid extra load/stores on 32-bit.  This
patch replaces the current definition with a structure of two 32-bit
quantities (pad and val), to clarify things as much as is possible.
The 'val' field is used when manipulating bits, the structure itself
is used when obtaining the address for loading/unloading the value
from the FPU.

While we're at it, consolidate the 4 (!) almost identical versions of
cvt_fd() and cvt_df() (arch/ppc/kernel/misc.S,
arch/ppc64/kernel/misc.S, arch/powerpc/kernel/misc_32.S,
arch/powerpc/kernel/misc_64.S) into a single version in fpu.S.  The
new version takes a pointer to thread_struct and applies the correct
offset itself, rather than a pointer to the fpscr field itself, again
to avoid confusion as to which is the correct field to use.

Finally, this patch makes ARCH=ppc64 also use the consolidated fpu.S
code, which it previously did not.

Built for G5 (ARCH=ppc64 and ARCH=powerpc), 32-bit powermac (ARCH=ppc
and ARCH=powerpc) and Walnut (ARCH=ppc, CONFIG_MATH_EMULATION=y).
Booted on G5 (ARCH=powerpc) and things which previously fell over no
longer do.
Signed-off-by: NDavid Gibson <dwg@au1.ibm.com>
Signed-off-by: NPaul Mackerras <paulus@samba.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!