Module Name: src
Committed By: riastradh
Date: Sat Aug 6 15:38:42 UTC 2022
Modified Files:
src/sys/dev/pci: if_sip.c
Log Message:
sip(4): Tidy up DMA syncs.
- No membar_producer in sip_init_rxdesc -- use bus_dmamap_sync with
BUS_DMASYNC_PREWRITE to order updates to the DMA descriptors.
- Omit needless membar_producer in sip_init_txdesc -- the hardware
will not look at any of these descriptors until we set CMDSTS_OWN
on the first one in the sequence, which is done later in the
caller, sipcom_start.
- In gsip_rxintr, make sure to read cmdsts _before_ extsts, by
separating them with BUS_DMASYNC_PREREAD. Otherwise, the CPU might
reorder the loads and read a stale extsts first before witnessing
an updated cmdsts with the CMDSTS_OWN bit that transfers ownership
of the rx packet to us.
To generate a diff of this commit:
cvs rdiff -u -r1.186 -r1.187 src/sys/dev/pci/if_sip.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/dev/pci/if_sip.c
diff -u src/sys/dev/pci/if_sip.c:1.186 src/sys/dev/pci/if_sip.c:1.187
--- src/sys/dev/pci/if_sip.c:1.186 Tue May 24 20:50:19 2022
+++ src/sys/dev/pci/if_sip.c Sat Aug 6 15:38:42 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: if_sip.c,v 1.186 2022/05/24 20:50:19 andvar Exp $ */
+/* $NetBSD: if_sip.c,v 1.187 2022/08/06 15:38:42 riastradh Exp $ */
/*-
* Copyright (c) 2001, 2002 The NetBSD Foundation, Inc.
@@ -73,7 +73,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_sip.c,v 1.186 2022/05/24 20:50:19 andvar Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_sip.c,v 1.187 2022/08/06 15:38:42 riastradh Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -569,7 +569,6 @@ sip_init_txdesc(struct sip_softc *sc, in
sipd->sipd_words[sc->sc_bufptr_idx] = htole32(bufptr);
}
sipd->sipd_words[sc->sc_extsts_idx] = 0;
- membar_producer();
sipd->sipd_words[sc->sc_cmdsts_idx] = htole32(cmdsts);
/* sip_cdtxsync() will be done later. */
}
@@ -596,7 +595,7 @@ sip_init_rxdesc(struct sip_softc *sc, in
htole32(rxs->rxs_dmamap->dm_segs[0].ds_addr);
}
sipd->sipd_words[sc->sc_extsts_idx] = 0;
- membar_producer();
+ sip_cdrxsync(sc, x, BUS_DMASYNC_PREWRITE);
sipd->sipd_words[sc->sc_cmdsts_idx] =
htole32(CMDSTS_INTR | (sc->sc_parm->p_rxbuf_len &
sc->sc_bits.b_cmdsts_size_mask));
@@ -2126,9 +2125,6 @@ gsip_rxintr(struct sip_softc *sc)
cmdsts =
le32toh(sc->sc_rxdescs[i].sipd_words[sc->sc_cmdsts_idx]);
- extsts =
- le32toh(sc->sc_rxdescs[i].sipd_words[sc->sc_extsts_idx]);
- len = CMDSTS_SIZE(sc, cmdsts);
/*
* NOTE: OWN is set if owned by _consumer_. We're the
@@ -2142,6 +2138,12 @@ gsip_rxintr(struct sip_softc *sc)
break;
}
+ sip_cdrxsync(sc, i, BUS_DMASYNC_POSTREAD);
+
+ extsts =
+ le32toh(sc->sc_rxdescs[i].sipd_words[sc->sc_extsts_idx]);
+ len = CMDSTS_SIZE(sc, cmdsts);
+
if (__predict_false(sc->sc_rxdiscard)) {
sip_init_rxdesc(sc, i);
if ((cmdsts & CMDSTS_MORE) == 0) {
