Patch "powerpc: Fix VSX enabling/flushing to also test MSR_FP and MSR_VEC" has been added to the 4.12-stable tree

This is a note to let you know that I've just added the patch titled

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

to the 4.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
powerpc-fix-vsx-enabling-flushing-to-also-test-msr_fp-and-msr_vec.patch
and it can be found in the queue-4.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Benjamin Herrenschmidt <[email protected]>
Date: Wed, 16 Aug 2017 16:01:14 +1000
Subject: powerpc: Fix VSX enabling/flushing to also test MSR_FP and MSR_VEC

From: Benjamin Herrenschmidt <[email protected]>

commit 5a69aec945d27e78abac9fd032533d3aaebf7c1e upstream.

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.

---
 arch/powerpc/kernel/process.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

@@ -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_str
 {
 	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);
 		}

Patches currently in stable-queue which might be from [email protected] are

queue-4.12/powerpc-fix-vsx-enabling-flushing-to-also-test-msr_fp-and-msr_vec.patch