x86/platform/UV: Remove Obsolete GRU MMR address translation

Use no-op messages in place of cross-partition interrupts when nacking a
put message in the GRU.  This allows us to remove MMR's as a destination
from the GRU driver.

Tested-by: John Estabrook <estabrook@sgi.com>
Tested-by: Gary Kroening <gfk@sgi.com>
Tested-by: Nathan Zimmer <nzimmer@sgi.com>
Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Andrew Banman <abanman@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
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: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russ Anderson <rja@sgi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160429215406.012228480@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 22 insertions, 26 deletions

diff --git a/arch/x86/include/asm/uv/uv_hub.h b/arch/x86/include/asm/uv/uv_hub.h
index ae979f7740f7..097b80c989c4 100644
--- a/arch/x86/include/asm/uv/uv_hub.h
+++ b/arch/x86/include/asm/uv/uv_hub.h
@@ -647,16 +647,6 @@ static inline unsigned long uv_read_global_mmr64(int pnode, unsigned long offset
         return readq(uv_global_mmr64_address(pnode, offset));
 }
 
-/*
- * Global MMR space addresses when referenced by the GRU. (GRU does
- * NOT use socket addressing).
- */
-static inline unsigned long uv_global_gru_mmr_address(int pnode, unsigned long offset)
-{
-        return UV_GLOBAL_GRU_MMR_BASE | offset |
-                ((unsigned long)pnode << uv_hub_info->m_val);
-}
-
 static inline void uv_write_global_mmr8(int pnode, unsigned long offset, unsigned char val)
 {
         writeb(val, uv_global_mmr64_address(pnode, offset));
diff --git a/drivers/misc/sgi-gru/grukservices.c b/drivers/misc/sgi-gru/grukservices.c
index 967b9dd24fe9..030769018461 100644
--- a/drivers/misc/sgi-gru/grukservices.c
+++ b/drivers/misc/sgi-gru/grukservices.c
@@ -718,8 +718,8 @@ cberr:
 static int send_message_put_nacked(void *cb, struct gru_message_queue_desc *mqd,
                         void *mesg, int lines)
 {
-        unsigned long m, *val = mesg, gpa, save;
-        int ret;
+        unsigned long m;
+        int ret, loops = 200;   /* experimentally determined */
 
         m = mqd->mq_gpa + (gru_get_amo_value_head(cb) << 6);
         if (lines == 2) {
@@ -735,22 +735,28 @@ static int send_message_put_nacked(void *cb, struct gru_message_queue_desc *mqd,
                 return MQE_OK;
 
         /*
-         * Send a cross-partition interrupt to the SSI that contains the target
-         * message queue. Normally, the interrupt is automatically delivered by
-         * hardware but some error conditions require explicit delivery.
-         * Use the GRU to deliver the interrupt. Otherwise partition failures
+         * Send a noop message in order to deliver a cross-partition interrupt
+         * to the SSI that contains the target message queue. Normally, the
+         * interrupt is automatically delivered by hardware following mesq
+         * operations, but some error conditions require explicit delivery.
+         * The noop message will trigger delivery. Otherwise partition failures
          * could cause unrecovered errors.
          */
-        gpa = uv_global_gru_mmr_address(mqd->interrupt_pnode, UVH_IPI_INT);
-        save = *val;
-        *val = uv_hub_ipi_value(mqd->interrupt_apicid, mqd->interrupt_vector,
-                                dest_Fixed);
-        gru_vstore_phys(cb, gpa, gru_get_tri(mesg), IAA_REGISTER, IMA);
-        ret = gru_wait(cb);
-        *val = save;
-        if (ret != CBS_IDLE)
-                return MQE_UNEXPECTED_CB_ERR;
-        return MQE_OK;
+        do {
+                ret = send_noop_message(cb, mqd, mesg);
+        } while ((ret == MQIE_AGAIN || ret == MQE_CONGESTION) && (loops-- > 0));
+
+        if (ret == MQIE_AGAIN || ret == MQE_CONGESTION) {
+                /*
+                 * Don't indicate to the app to resend the message, as it's
+                 * already been successfully sent.  We simply send an OK
+                 * (rather than fail the send with MQE_UNEXPECTED_CB_ERR),
+                 * assuming that the other side is receiving enough
+                 * interrupts to get this message processed anyway.
+                 */
+                ret = MQE_OK;
+        }
+        return ret;
 }
 
 /*