Since we pass flags to the compiler to control code generation based
on the least capable selected CPU, if we want to include VFP support,
we must tweak the assembler flags to allow the VFP instructions.
Moreover, we must not use the mrrc/mcrr versions since these will not
be recognised by the assembler.
We do not convert all instructions to the VFP-equivalent (yet) since
binutils appears to barf on "fmrx rn, fpinst" and doesn't provide any
other way (other than using the mrc equivalent) to encode this
instruction - which is rather a problem when you have a VFP
implementation which requires these instructions.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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: Russell 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: George G. Davis <gdavis@mvista.com>
Signed-off-by: Russell 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: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Catalin Marinas
This patch changes the double registers numbering to 0-15 from even 0-30,
in preparation for future VFP extensions. It also fixes the VFP_REG_ZERO
bug (value 16 actually represents the 8th double register with the original
numbering).
The original mcrr/mrrc on CP10 were generating FMRRS/FMSRR instead of
FMRRD/FMDRR. The patch changes to CP11 for the correct instructions.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Catalin Marinas
The NaN case was dealed with by the "exponent >= ... + 32" condition but it
was not setting the value "d" to 0.
Signed-off-by: Ken'ichi Kuromusha <musha@aplix.co.jp>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Catalin Marinas
The current VFP code corrupts the VFP registers (including the control
ones) if more than one floating point application is executed at the same
time. This patch fixes the updating of the load/store base addresses for
the VFP registers.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
5d25ac038a broke VFP builds due to
enable_irq not being defined as an assembly macro. Move it to
assembler.h so everyone can use it.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Allow the individual coprocessor handlers to decide when to enable
interrupts, rather than unconditionally enabling them.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Catalin Marinas
The IEEE 754 standard specifies that the result of (x - x), where x is
a valid number, should be -0 if the rounding mode is towards minus
infinity or +0 otherwise.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
VFP used __divdi3 64-bit division needlessly. Convert it to use
our 64-bit by 32-bit division instead.
Signed-off-by: Russell 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!
Russell King