Module Name: src
Committed By: riastradh
Date: Sun Feb 27 14:17:10 UTC 2022
Modified Files:
src/sys/arch/alpha/alpha: cpu.c
Log Message:
alpha: Fix placement of membar for sending ICCB message.
While here, reduce it to membar_exit -- it's obviously not needed for
store-before-load here (although alpha doesn't have anything weaker
than the full sequential consistency `mb'), and although we do need a
store-before-load (and load-before-load) to spin waiting for the CPU
to wake up, that already happens a few lines below with alpha_mb in
the loop anyway. So no need for membar_sync, which is just `mb'
under the hood -- deleting the membar_sync in this place can't hurt.
The membar_sync had been inserted automatically when converting from
an older style of atomic_ops(3) API.
To generate a diff of this commit:
cvs rdiff -u -r1.104 -r1.105 src/sys/arch/alpha/alpha/cpu.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/alpha/alpha/cpu.c
diff -u src/sys/arch/alpha/alpha/cpu.c:1.104 src/sys/arch/alpha/alpha/cpu.c:1.105
--- src/sys/arch/alpha/alpha/cpu.c:1.104 Wed May 5 03:54:16 2021
+++ src/sys/arch/alpha/alpha/cpu.c Sun Feb 27 14:17:10 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: cpu.c,v 1.104 2021/05/05 03:54:16 thorpej Exp $ */
+/* $NetBSD: cpu.c,v 1.105 2022/02/27 14:17:10 riastradh Exp $ */
/*-
* Copyright (c) 1998, 1999, 2000, 2001, 2020 The NetBSD Foundation, Inc.
@@ -59,7 +59,7 @@
#include <sys/cdefs.h> /* RCS ID & Copyright macro defns */
-__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.104 2021/05/05 03:54:16 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.105 2022/02/27 14:17:10 riastradh Exp $");
#include "opt_ddb.h"
#include "opt_multiprocessor.h"
@@ -882,12 +882,13 @@ cpu_iccb_send(long cpu_id, const char *m
/*
* Copy the message into the ICCB, and tell the secondary console
- * that it's there.
+ * that it's there. Ensure the buffer is initialized before we
+ * set the rxrdy bits, as a store-release.
*/
strcpy(pcsp->pcs_iccb.iccb_rxbuf, msg);
pcsp->pcs_iccb.iccb_rxlen = strlen(msg);
+ membar_exit();
atomic_or_ulong(&hwrpb->rpb_rxrdy, cpumask);
- membar_sync();
/* Wait for the message to be received. */
for (timeout = 10000; timeout != 0; timeout--) {
