The Multi-MSI interrupt handler doesn't clear the DMA error interrupts, and this leads to interrupt storms when one of these interrupts starts firing : - The RBU (rx buff unav) which triggers under high traffic load This triggers easily with iperf3 and small udp packets, and shows when running the netpoll kselftest - The RPS (rx process stop) which triggers when we stop the DMA RX. This one shows when restarting the RX logic without doing a down/up cycle, like when attaching an XDP program. The XSK kselftests triggers it. Let's make sure we clear these interrupts for multi-MSI cases, and call stmmac_global_err() upon tx_hard_error to avoid possible races with other interrupts/napi. For that introduce an "ERR" DMA dir, as we don't want to touch the RI/TI bits when handling these interrupts. Both of the above storms have been found on dwmac-motorcomm (YT6801), and are triggered by the xdp.py, xsk_reconfig.py, xdp_features.py, ring_reconfig.py and netpoll_basic kernel selftests. This seems to only affect dwmac4, there's no multi-msi mode on dwmac1000, and on dwxgmac these interrupts are masked as of today. Fixes: 6ccf12ae111e ("net: stmmac: use interrupt mode INTM=1 for multi-MSI") Signed-off-by: Maxime Chevallier --- V2: - Dropped reviews/tested tags as the implementation has substantially changed, sorry :( - Discarded the helper, call directly stmmac_dma_interrupt_status on all chans and use stmmac_global_err() for TX hard errors, following sashiko's review. drivers/net/ethernet/stmicro/stmmac/common.h | 1 + .../net/ethernet/stmicro/stmmac/dwmac4_dma.h | 5 +++++ .../net/ethernet/stmicro/stmmac/dwmac4_lib.c | 2 ++ .../net/ethernet/stmicro/stmmac/stmmac_main.c | 19 +++++++++++++++++++ 4 files changed, 27 insertions(+) diff --git a/drivers/net/ethernet/stmicro/stmmac/common.h b/drivers/net/ethernet/stmicro/stmmac/common.h index c74bc7c9750e..a972bee66504 100644 --- a/drivers/net/ethernet/stmicro/stmmac/common.h +++ b/drivers/net/ethernet/stmicro/stmmac/common.h @@ -382,6 +382,7 @@ enum dma_irq_dir { DMA_DIR_RX = 0x1, DMA_DIR_TX = 0x2, DMA_DIR_RXTX = 0x3, + DMA_DIR_ERR = 0x4, }; enum request_irq_err { diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h index 43b036d4e95b..a7caac3c98e6 100644 --- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h @@ -173,6 +173,11 @@ static inline u32 dma_chanx_base_addr(const struct dwmac4_addrs *addrs, DMA_CHAN_STATUS_TI | \ DMA_CHAN_STATUS_MSK_COMMON) +#define DMA_CHAN_STATUS_MSK_ERR (DMA_CHAN_STATUS_AIS | \ + DMA_CHAN_STATUS_FBE | \ + DMA_CHAN_STATUS_RPS | \ + DMA_CHAN_STATUS_RBU) + int dwmac4_dma_reset(void __iomem *ioaddr); void dwmac4_enable_dma_irq(struct stmmac_priv *priv, void __iomem *ioaddr, u32 chan, bool rx, bool tx); diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_lib.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_lib.c index a0249715fafa..02aa1a3dd1e2 100644 --- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_lib.c +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_lib.c @@ -150,6 +150,8 @@ int dwmac4_dma_interrupt(struct stmmac_priv *priv, void __iomem *ioaddr, intr_status &= DMA_CHAN_STATUS_MSK_RX; else if (dir == DMA_DIR_TX) intr_status &= DMA_CHAN_STATUS_MSK_TX; + else if (dir == DMA_DIR_ERR) + intr_status &= DMA_CHAN_STATUS_MSK_ERR; /* ABNORMAL interrupts */ if (unlikely(intr_status & DMA_CHAN_STATUS_AIS)) { diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index 7ffed295eb14..6360605ef5ea 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -3145,6 +3145,22 @@ static int stmmac_napi_check(struct stmmac_priv *priv, u32 chan, u32 dir) return status; } +static void stmmac_dma_err_interrupt(struct stmmac_priv *priv) +{ + u8 channels_to_check = max(priv->plat->rx_queues_to_use, + priv->plat->tx_queues_to_use); + int status; + u8 chan; + + for (chan = 0; chan < channels_to_check; chan++) { + status = stmmac_dma_interrupt_status(priv, priv->ioaddr, + &priv->xstats, chan, + DMA_DIR_ERR); + if (unlikely(status & tx_hard_error)) + stmmac_global_err(priv); + } +} + /** * stmmac_dma_interrupt - DMA ISR * @priv: driver private structure @@ -6494,6 +6510,9 @@ static irqreturn_t stmmac_mac_interrupt(int irq, void *dev_id) /* To handle Common interrupts */ stmmac_common_interrupt(priv); + if (priv->plat->core_type == DWMAC_CORE_GMAC4) + stmmac_dma_err_interrupt(priv); + return IRQ_HANDLED; } -- 2.56.0