x86/platform/uv/BAU: Fix HUB errors by remove initial write to sw-ack register

[ Upstream commit 1b17c6df85 ]

Writing to the software acknowledge clear register when there are no
pending messages causes a HUB error to assert. The original intent of this
write was to clear the pending bits before start of operation, but this is
an incorrect method and has been determined to be unnecessary.

Signed-off-by: Andrew Banman <abanman@hpe.com>
Acked-by: Mike Travis <mike.travis@hpe.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akpm@linux-foundation.org
Cc: rja@hpe.com
Cc: sivanich@hpe.com
Link: http://lkml.kernel.org/r/1487351269-181133-1-git-send-email-abanman@hpe.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/x86/platform/uv/tlb_uv.c

@@ -1848,7 +1848,6 @@ static void pq_init(int node, int pnode)
 
 	ops.write_payload_first(pnode, first);
 	ops.write_payload_last(pnode, last);
-	ops.write_g_sw_ack(pnode, 0xffffUL);
 
 	/* in effect, all msg_type's are set to MSG_NOOP */
 	memset(pqp, 0, sizeof(struct bau_pq_entry) * DEST_Q_SIZE);