The current lazy saving of the VFP registers is no longer possible
with thread migration on SMP. This patch implements a per-CPU
vfp-state pointer and the saving of the VFP registers at every context
switch. The registers restoring is still performed in a lazy way.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

When we install the handlers for context switching, we must enable
VFP on all CPU cores, otherwise undefined (and random) effects
occur.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Don't set HWCAP_VFP in the processor support file; not only does it
depend on the processor features, but it also depends on the support
code being present.  Therefore, only set it if the support code
detects that we have a VFP coprocessor attached.

Also, move the VFP handling of the coprocessor access register into
the VFP support code.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The SIGFPE signal should be generated if Division by Zero exception is detected.
Signed-off-by: NTakashi Ohmasa <ohmasa.takashi@jp.panasonic.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The common case for the thread notifier is a context switch.  Tell
gcc that this is the most likely condition so it can optimise the
function for this case.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Daniel Jacobowitz

The recent fix to hide VFP_NAN_FLAG broke the check in vfp_raise_exceptions;
it would attempt to deliver an exception mask of 0xfffffeff instead of reporting
a serious error condition using printk.  Define a safe constant to use for
an invalid exception maskm, and use it at both ends.
Signed-off-by: NDaniel Jacobowitz <dan@codesourcery.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NJörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>

Some machine classes need to allow VFP support to be built into the
kernel, but still allow the kernel to run even though VFP isn't
present.  Unfortunately, the kernel hard-codes VFP instructions
into the thread switch, which prevents this being run-time selectable.

Solve this by introducing a notifier which things such as VFP can
hook into to be informed of events which affect the VFP subsystem
(eg, creation and destruction of threads, switches between threads.)
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from George G. Davis

The ARM VFP FPSCR register is corrupted when a condition flags modifying
VFP instruction is followed by a non-condition flags modifying VFP
instruction and both instructions raise exceptions.  The fix is to
read the current FPSCR in between emulation of these two instructions
and use the current FPSCR value when handling the second exception.
Signed-off-by: NGeorge G. Davis <gdavis@mvista.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The VFP code can leak VFP_NAN_FLAG into the FPSCR. It doesn't correspond
to any real FPSCR bit (and overlaps one of the exception flags).

Bug report from Daniel Jacobowitz
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

We were forcing SIGFPE on to a user program for no good reason.
Use send_sig_info() instead.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

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!