s390/fpu: signals vs. floating point control register

s390/fpu: signals vs. floating point control register

commit 1b17cb796f5d40ffa239c6926385abd83a77a49b upstream.

git commit 904818e2f229f3d94ec95f6932a6358c81e73d78
"s390/kernel: introduce fpu-internal.h with fpu helper functions"
introduced the fpregs_store / fp_regs_load helper. These function
fail to save and restore the floating pointer control registers.

The effect is that the FPC is not correctly handled on signal
delivery and signal return.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>