powerpc: Fix VSX enabling/flushing to also test MSR_FP and MSR_VEC

VSX uses a combination of the old vector registers, the old FP
registers and new "second halves" of the FP registers.

Thus when we need to see the VSX state in the thread struct
(flush_vsx_to_thread()) or when we'll use the VSX in the kernel
(enable_kernel_vsx()) we need to ensure they are all flushed into
the thread struct if either of them is individually enabled.

Unfortunately we only tested if the whole VSX was enabled, not if they
were individually enabled.

Fixes: 72cd7b44bc99 ("powerpc: Uncomment and make enable_kernel_vsx() routine available")
Cc: stable@vger.kernel.org # v4.3+
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index ec480966f9bf55f17184537f64e7d10c40c723c0..1f0fd361e09b9415f81242d67d9b939f36fd63ba 100644 (file)
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -362,7 +362,8 @@ void enable_kernel_vsx(void)
 
        cpumsr = msr_check_and_set(MSR_FP|MSR_VEC|MSR_VSX);
 
-       if (current->thread.regs && (current->thread.regs->msr & MSR_VSX)) {
+       if (current->thread.regs &&
+           (current->thread.regs->msr & (MSR_VSX|MSR_VEC|MSR_FP))) {
                check_if_tm_restore_required(current);
                /*
                 * If a thread has already been reclaimed then the
@@ -386,7 +387,7 @@ void flush_vsx_to_thread(struct task_struct *tsk)
 {
        if (tsk->thread.regs) {
                preempt_disable();
-               if (tsk->thread.regs->msr & MSR_VSX) {
+               if (tsk->thread.regs->msr & (MSR_VSX|MSR_VEC|MSR_FP)) {
                        BUG_ON(tsk != current);
                        giveup_vsx(tsk);
                }