powerpc: keep the VSX halves of the FPRs across back-to-back signalsHEADmain

grab_mcontext() only put the second halves of vs0-31 into the context
while the thread owned the VSX unit, but sigreturn(2) gives ownership
up so that the next use reloads the registers lazily. A signal that
arrives right after a sigreturn, like one the handler's mask was
holding back, got a context without them and its own sigreturn then
zeroed them in the PCB.

The halves saved in the PCB are current whenever the FP state is, since
VSX instructions can't run without PCB_VSX and save_fpu() stores them
in that case, so export them together with the FP registers.

Reviewed by:	jhibbits
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D60754

0 files changed, 0 insertions, 0 deletions