sfc: Validate IRQ moderation parameters in efx_init_irq_moderation()

Add a range check, and move the check that RX and TX are consistent
from efx_ethtool_set_coalesce().

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 34 insertions, 15 deletions

diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
index e0157c03d313..76dcadfaaa43 100644
--- a/drivers/net/ethernet/sfc/efx.c
+++ b/drivers/net/ethernet/sfc/efx.c
@@ -1357,7 +1357,8 @@ static int efx_probe_nic(struct efx_nic *efx)
         netif_set_real_num_rx_queues(efx->net_dev, efx->n_rx_channels);
 
         /* Initialise the interrupt moderation settings */
-        efx_init_irq_moderation(efx, tx_irq_mod_usec, rx_irq_mod_usec, true);
+        efx_init_irq_moderation(efx, tx_irq_mod_usec, rx_irq_mod_usec, true,
+                                true);
 
         return 0;
 
@@ -1566,8 +1567,9 @@ static unsigned int irq_mod_ticks(unsigned int usecs, unsigned int resolution)
 }
 
 /* Set interrupt moderation parameters */
-void efx_init_irq_moderation(struct efx_nic *efx, unsigned int tx_usecs,
-                             unsigned int rx_usecs, bool rx_adaptive)
+int efx_init_irq_moderation(struct efx_nic *efx, unsigned int tx_usecs,
+                            unsigned int rx_usecs, bool rx_adaptive,
+                            bool rx_may_override_tx)
 {
         struct efx_channel *channel;
         unsigned tx_ticks = irq_mod_ticks(tx_usecs, EFX_IRQ_MOD_RESOLUTION);
@@ -1575,6 +1577,16 @@ void efx_init_irq_moderation(struct efx_nic *efx, unsigned int tx_usecs,
 
         EFX_ASSERT_RESET_SERIALISED(efx);
 
+        if (tx_ticks > EFX_IRQ_MOD_MAX || rx_ticks > EFX_IRQ_MOD_MAX)
+                return -EINVAL;
+
+        if (tx_ticks != rx_ticks && efx->tx_channel_offset == 0 &&
+            !rx_may_override_tx) {
+                netif_err(efx, drv, efx->net_dev, "Channels are shared. "
+                          "RX and TX IRQ moderation must be equal\n");
+                return -EINVAL;
+        }
+
         efx->irq_rx_adaptive = rx_adaptive;
         efx->irq_rx_moderation = rx_ticks;
         efx_for_each_channel(channel, efx) {
@@ -1583,6 +1595,8 @@ void efx_init_irq_moderation(struct efx_nic *efx, unsigned int tx_usecs,
                 else if (efx_channel_has_tx_queues(channel))
                         channel->irq_moderation = tx_ticks;
         }
+
+        return 0;
 }
 
 void efx_get_irq_moderation(struct efx_nic *efx, unsigned int *tx_usecs,
diff --git a/drivers/net/ethernet/sfc/efx.h b/drivers/net/ethernet/sfc/efx.h
index 8ca68631fce5..442f4d0c247d 100644
--- a/drivers/net/ethernet/sfc/efx.h
+++ b/drivers/net/ethernet/sfc/efx.h
@@ -111,8 +111,9 @@ extern int efx_reset_up(struct efx_nic *efx, enum reset_type method, bool ok);
 
 /* Global */
 extern void efx_schedule_reset(struct efx_nic *efx, enum reset_type type);
-extern void efx_init_irq_moderation(struct efx_nic *efx, unsigned int tx_usecs,
-                                    unsigned int rx_usecs, bool rx_adaptive);
+extern int efx_init_irq_moderation(struct efx_nic *efx, unsigned int tx_usecs,
+                                   unsigned int rx_usecs, bool rx_adaptive,
+                                   bool rx_may_override_tx);
 extern void efx_get_irq_moderation(struct efx_nic *efx, unsigned int *tx_usecs,
                                    unsigned int *rx_usecs, bool *rx_adaptive);
 
diff --git a/drivers/net/ethernet/sfc/ethtool.c b/drivers/net/ethernet/sfc/ethtool.c
index 1cb6ed0a255c..98b363bb4a75 100644
--- a/drivers/net/ethernet/sfc/ethtool.c
+++ b/drivers/net/ethernet/sfc/ethtool.c
@@ -623,7 +623,8 @@ static int efx_ethtool_set_coalesce(struct net_device *net_dev,
         struct efx_nic *efx = netdev_priv(net_dev);
         struct efx_channel *channel;
         unsigned int tx_usecs, rx_usecs;
-        bool adaptive;
+        bool adaptive, rx_may_override_tx;
+        int rc;
 
         if (coalesce->use_adaptive_tx_coalesce)
                 return -EINVAL;
@@ -642,16 +643,14 @@ static int efx_ethtool_set_coalesce(struct net_device *net_dev,
         /* If channels are shared, TX IRQ moderation can be quietly
          * overridden unless it is changed from its old value.
          */
-        if (efx->tx_channel_offset == 0 &&
-            coalesce->tx_coalesce_usecs_irq != tx_usecs &&
-            coalesce->tx_coalesce_usecs_irq != rx_usecs) {
-                netif_err(efx, drv, efx->net_dev, "Channels are shared. "
-                          "RX and TX IRQ moderation must be equal\n");
-                return -EINVAL;
-        }
+        rx_may_override_tx = coalesce->tx_coalesce_usecs_irq == tx_usecs;
         tx_usecs = coalesce->tx_coalesce_usecs_irq;
 
-        efx_init_irq_moderation(efx, tx_usecs, rx_usecs, adaptive);
+        rc = efx_init_irq_moderation(efx, tx_usecs, rx_usecs, adaptive,
+                                     rx_may_override_tx);
+        if (rc != 0)
+                return rc;
+
         efx_for_each_channel(channel, efx)
                 efx->type->push_irq_moderation(channel);
 
diff --git a/drivers/net/ethernet/sfc/falcon.c b/drivers/net/ethernet/sfc/falcon.c
index 94bf4aaf984d..4dd1748a19c6 100644
--- a/drivers/net/ethernet/sfc/falcon.c
+++ b/drivers/net/ethernet/sfc/falcon.c
@@ -104,6 +104,8 @@ static void falcon_push_irq_moderation(struct efx_channel *channel)
         efx_dword_t timer_cmd;
         struct efx_nic *efx = channel->efx;
 
+        BUILD_BUG_ON(EFX_IRQ_MOD_MAX > (1 << FRF_AB_TC_TIMER_VAL_WIDTH));
+
         /* Set timer register */
         if (channel->irq_moderation) {
                 EFX_POPULATE_DWORD_2(timer_cmd,
diff --git a/drivers/net/ethernet/sfc/nic.h b/drivers/net/ethernet/sfc/nic.h
index 4bd1f2839dfe..b5b288628c6b 100644
--- a/drivers/net/ethernet/sfc/nic.h
+++ b/drivers/net/ethernet/sfc/nic.h
@@ -204,7 +204,8 @@ extern irqreturn_t efx_nic_fatal_interrupt(struct efx_nic *efx);
 extern irqreturn_t falcon_legacy_interrupt_a1(int irq, void *dev_id);
 extern void falcon_irq_ack_a1(struct efx_nic *efx);
 
-#define EFX_IRQ_MOD_RESOLUTION 5
+#define EFX_IRQ_MOD_RESOLUTION  5
+#define EFX_IRQ_MOD_MAX         0x1000
 
 /* Global Resources */
 extern int efx_nic_flush_queues(struct efx_nic *efx);
diff --git a/drivers/net/ethernet/sfc/siena.c b/drivers/net/ethernet/sfc/siena.c
index 5735e84c69de..4fdd148747b2 100644
--- a/drivers/net/ethernet/sfc/siena.c
+++ b/drivers/net/ethernet/sfc/siena.c
@@ -36,6 +36,8 @@ static void siena_push_irq_moderation(struct efx_channel *channel)
 {
         efx_dword_t timer_cmd;
 
+        BUILD_BUG_ON(EFX_IRQ_MOD_MAX > (1 << FRF_CZ_TC_TIMER_VAL_WIDTH));
+
         if (channel->irq_moderation)
                 EFX_POPULATE_DWORD_2(timer_cmd,
                                      FRF_CZ_TC_TIMER_MODE,