netdev - [PATCH net 8/8] net: mscc: ocelot: report ndo_get_stats64 from the wraparound-resistant ocelot->stats

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 16 Aug 2022 16:53:52 +0300
From:   Vladimir Oltean <vladimir.oltean@....com>
To:     netdev@...r.kernel.org
Cc:     Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Claudiu Manoil <claudiu.manoil@....com>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        UNGLinuxDriver@...rochip.com,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Colin Foster <colin.foster@...advantage.com>,
        Maxim Kochetkov <fido_max@...ox.ru>
Subject: [PATCH net 8/8] net: mscc: ocelot: report ndo_get_stats64 from the wraparound-resistant ocelot->stats

Rather than reading the stats64 counters directly from the 32-bit
hardware, it's better to rely on the output produced by the periodic
ocelot_port_update_stats().

It would be even better to call ocelot_port_update_stats() right from
ocelot_get_stats64() to make sure we report the current values rather
than the ones from 2 seconds ago. But we need to export
ocelot_port_update_stats() from the switch lib towards the switchdev
driver for that, and future work will largely undo that.

There are more ocelot-based drivers waiting to be introduced, an example
of which is the SPI-controlled VSC7512. In that driver's case, it will
be impossible to call ocelot_port_update_stats() from ndo_get_stats64
context, since the latter is atomic, and reading the stats over SPI is
sleepable. So the compromise taken here, which will also hold going
forward, is to report 64-bit counters to stats64, which are not 100% up
to date.

Fixes: a556c76adc05 ("net: mscc: Add initial Ocelot switch support")
Signed-off-by: Vladimir Oltean <vladimir.oltean@....com>
---
 drivers/net/ethernet/mscc/ocelot_net.c | 53 +++++++++++++-------------
 1 file changed, 26 insertions(+), 27 deletions(-)

diff --git a/drivers/net/ethernet/mscc/ocelot_net.c b/drivers/net/ethernet/mscc/ocelot_net.c
index 6b9d37138844..330d30841cdc 100644
--- a/drivers/net/ethernet/mscc/ocelot_net.c
+++ b/drivers/net/ethernet/mscc/ocelot_net.c
@@ -725,41 +725,40 @@ static void ocelot_get_stats64(struct net_device *dev,
 	struct ocelot_port_private *priv = netdev_priv(dev);
 	struct ocelot *ocelot = priv->port.ocelot;
 	int port = priv->port.index;
+	u64 *s;
 
 	spin_lock(&ocelot->stats_lock);
 
-	/* Configure the port to read the stats from */
-	ocelot_write(ocelot, SYS_STAT_CFG_STAT_VIEW(port),
-		     SYS_STAT_CFG);
+	s = &ocelot->stats[port * OCELOT_NUM_STATS];
 
 	/* Get Rx stats */
-	stats->rx_bytes = ocelot_read(ocelot, SYS_COUNT_RX_OCTETS);
-	stats->rx_packets = ocelot_read(ocelot, SYS_COUNT_RX_SHORTS) +
-			    ocelot_read(ocelot, SYS_COUNT_RX_FRAGMENTS) +
-			    ocelot_read(ocelot, SYS_COUNT_RX_JABBERS) +
-			    ocelot_read(ocelot, SYS_COUNT_RX_LONGS) +
-			    ocelot_read(ocelot, SYS_COUNT_RX_64) +
-			    ocelot_read(ocelot, SYS_COUNT_RX_65_127) +
-			    ocelot_read(ocelot, SYS_COUNT_RX_128_255) +
-			    ocelot_read(ocelot, SYS_COUNT_RX_256_511) +
-			    ocelot_read(ocelot, SYS_COUNT_RX_512_1023) +
-			    ocelot_read(ocelot, SYS_COUNT_RX_1024_1526) +
-			    ocelot_read(ocelot, SYS_COUNT_RX_1527_MAX);
-	stats->multicast = ocelot_read(ocelot, SYS_COUNT_RX_MULTICAST);
+	stats->rx_bytes = s[OCELOT_STAT_RX_OCTETS];
+	stats->rx_packets = s[OCELOT_STAT_RX_SHORTS] +
+			    s[OCELOT_STAT_RX_FRAGMENTS] +
+			    s[OCELOT_STAT_RX_JABBERS] +
+			    s[OCELOT_STAT_RX_LONGS] +
+			    s[OCELOT_STAT_RX_64] +
+			    s[OCELOT_STAT_RX_65_127] +
+			    s[OCELOT_STAT_RX_128_255] +
+			    s[OCELOT_STAT_RX_256_511] +
+			    s[OCELOT_STAT_RX_512_1023] +
+			    s[OCELOT_STAT_RX_1024_1526] +
+			    s[OCELOT_STAT_RX_1527_MAX];
+	stats->multicast = s[OCELOT_STAT_RX_MULTICAST];
 	stats->rx_dropped = dev->stats.rx_dropped;
 
 	/* Get Tx stats */
-	stats->tx_bytes = ocelot_read(ocelot, SYS_COUNT_TX_OCTETS);
-	stats->tx_packets = ocelot_read(ocelot, SYS_COUNT_TX_64) +
-			    ocelot_read(ocelot, SYS_COUNT_TX_65_127) +
-			    ocelot_read(ocelot, SYS_COUNT_TX_128_255) +
-			    ocelot_read(ocelot, SYS_COUNT_TX_256_511) +
-			    ocelot_read(ocelot, SYS_COUNT_TX_512_1023) +
-			    ocelot_read(ocelot, SYS_COUNT_TX_1024_1526) +
-			    ocelot_read(ocelot, SYS_COUNT_TX_1527_MAX);
-	stats->tx_dropped = ocelot_read(ocelot, SYS_COUNT_TX_DROPS) +
-			    ocelot_read(ocelot, SYS_COUNT_TX_AGING);
-	stats->collisions = ocelot_read(ocelot, SYS_COUNT_TX_COLLISION);
+	stats->tx_bytes = s[OCELOT_STAT_TX_OCTETS];
+	stats->tx_packets = s[OCELOT_STAT_TX_64] +
+			    s[OCELOT_STAT_TX_65_127] +
+			    s[OCELOT_STAT_TX_128_255] +
+			    s[OCELOT_STAT_TX_256_511] +
+			    s[OCELOT_STAT_TX_512_1023] +
+			    s[OCELOT_STAT_TX_1024_1526] +
+			    s[OCELOT_STAT_TX_1527_MAX];
+	stats->tx_dropped = s[OCELOT_STAT_TX_DROPS] +
+			    s[OCELOT_STAT_TX_AGED];
+	stats->collisions = s[OCELOT_STAT_TX_COLLISION];
 
 	spin_unlock(&ocelot->stats_lock);
 }
-- 
2.34.1