x86/platform/uv/BAU: Add status mmr location fields to bau_control

The location of the ERROR and BUSY status bits depends on the descriptor
index, i.e. the CPU, of the message. Since this index does not change,
there is no need to calculate the mmr and index location during message
processing. The less work we do in the hot path the better.

Add status_mmr and status_index fields to bau_control and compute their
values during initialization. Add kerneldoc descriptions for the new
fields. Update uv*_wait_completion to use these fields rather than
receiving the information as parameters.

Signed-off-by: Andrew Banman <abanman@hpe.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Mike Travis <mike.travis@hpe.com>
Cc: sivanich@hpe.com
Cc: rja@hpe.com
Cc: akpm@linux-foundation.org
Link: http://lkml.kernel.org/r/1489077734-111753-5-git-send-email-abanman@hpe.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 8 insertions, 2 deletions

diff --git a/arch/x86/include/asm/uv/uv_bau.h b/arch/x86/include/asm/uv/uv_bau.h
index 695b873f4fd3..0ec7631ad651 100644
--- a/arch/x86/include/asm/uv/uv_bau.h
+++ b/arch/x86/include/asm/uv/uv_bau.h
@@ -601,8 +601,12 @@ struct uvhub_desc {
         struct socket_desc      socket[2];
 };
 
-/*
- * one per-cpu; to locate the software tables
+/**
+ * struct bau_control
+ * @status_mmr: location of status mmr, determined by uvhub_cpu
+ * @status_index: index of ERR|BUSY bits in status mmr, determined by uvhub_cpu
+ *
+ * Per-cpu control struct containing CPU topology information and BAU tuneables.
  */
 struct bau_control {
         struct bau_desc         *descriptor_base;
@@ -620,6 +624,8 @@ struct bau_control {
         int                     timeout_tries;
         int                     ipi_attempts;
         int                     conseccompletes;
+        u64                     status_mmr;
+        int                     status_index;
         bool                    nobau;
         short                   baudisabled;
         short                   cpu;