[Skiboot] [PATCH] FSP: Add check to detect FSP R/R inside fsp_sync_msg()

[Vasant Hegde]

OPAL sends MBOX message to FSP and updates message state from fsp_msg_queued
-> fsp_msg_sent. fsp_sync_msg() queues message and waits until we get response
from FSP. During FSP R/R we move outstanding MBOX messages from msgq to rr_queue
including inflight message (fsp_reset_cmdclass()). But we are not resetting
inflight message state.

In extreme croner case where we sent message to FSP via fsp_sync_msg() path
and FSP R/R happens before getting respose from FSP, then we will endup waiting
in fsp_sync_msg() until everything becomes normal.

This patch adds fsp_in_rr() check to fsp_sync_msg() and return error to caller
if FSP is in R/R.

CC: Ananth N Mavinakayanahalli <ananth at linux.vnet.ibm.com>
Signed-off-by: Vasant Hegde <hegdevasant at linux.vnet.ibm.com>
---
 hw/fsp/fsp.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/hw/fsp/fsp.c b/hw/fsp/fsp.c
index 4c888c8..4d17397 100644
--- a/hw/fsp/fsp.c
+++ b/hw/fsp/fsp.c
@@ -282,9 +282,8 @@ void fsp_cancelmsg(struct fsp_msg *msg)
 {
 	bool need_unlock = false;
 	struct fsp_cmdclass* cmdclass = fsp_get_cmdclass(msg);
-	struct fsp *fsp = fsp_get_active();
 
-	if (fsp->state != fsp_mbx_rr) {
+	if (!fsp_in_rr()) {
 		prerror("FSP: Message cancel allowed only when"
 						"FSP is in reset\n");
 		return;
@@ -1745,6 +1744,11 @@ int fsp_sync_msg(struct fsp_msg *msg, bool autofree)
 		goto bail;
 
 	while(fsp_msg_busy(msg)) {
+		if (fsp_in_rr()) {
+			fsp_cancelmsg(msg);
+			rc = -1;
+			goto bail;
+		}
 		cpu_relax();
 		opal_run_pollers();
 	}
@@ -2033,6 +2037,11 @@ int fsp_fatal_msg(struct fsp_msg *msg)
 		return rc;
 
 	while(fsp_msg_busy(msg)) {
+		if (fsp_in_rr()) {
+			fsp_cancelmsg(msg);
+			return -1;
+		}
+
 		cpu_relax();
 		fsp_opal_poll(NULL);
 	}
-- 
2.9.3