diff mbox series

[1/6] net: stmmac: use correct DMA buffer size in the RX descriptor

Message ID 20190327203540.1884-2-aaro.koskinen@iki.fi
State Accepted
Delegated to: David Miller
Headers show
Series net: stmmac: fix handling of oversized frames | expand

Commit Message

Aaro Koskinen March 27, 2019, 8:35 p.m. UTC 
From: Aaro Koskinen <aaro.koskinen@nokia.com>

We always program the maximum DMA buffer size into the receive descriptor,
although the allocated size may be less. E.g. with the default MTU size
we allocate only 1536 bytes. If somebody sends us a bigger frame, then
memory may get corrupted.

Fix by using exact buffer sizes.

Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
---
 .../net/ethernet/stmicro/stmmac/descs_com.h   | 22 ++++++++++++-------
 .../ethernet/stmicro/stmmac/dwmac4_descs.c    |  2 +-
 .../ethernet/stmicro/stmmac/dwxgmac2_descs.c  |  2 +-
 .../net/ethernet/stmicro/stmmac/enh_desc.c    | 10 ++++++---
 drivers/net/ethernet/stmicro/stmmac/hwif.h    |  2 +-
 .../net/ethernet/stmicro/stmmac/norm_desc.c   | 10 ++++++---
 .../net/ethernet/stmicro/stmmac/stmmac_main.c |  6 +++--
 7 files changed, 35 insertions(+), 19 deletions(-)

Comments

Jose Abreu March 29, 2019, 10:02 a.m. UTC | #1 
On 3/27/2019 8:35 PM, Aaro Koskinen wrote:
> From: Aaro Koskinen <aaro.koskinen@nokia.com>
> 
> We always program the maximum DMA buffer size into the receive descriptor,
> although the allocated size may be less. E.g. with the default MTU size
> we allocate only 1536 bytes. If somebody sends us a bigger frame, then
> memory may get corrupted.
> 
> Fix by using exact buffer sizes.
> 
> Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>

So, I'm seeing that the maximum allowed buffer size that can be
put in the descriptor changes between enhanced descriptors to
normal descriptors (8KB vs. 2KB right ?).

Shouldn't stmmac_main know about this limit before trying to init
descriptors ?

We do limit the MTU according to HW version but I would rather
prefer not having to need to calculate min() values in the
descriptor code and just use the value as is ...

Thanks,
Jose Miguel Abreu
Aaro Koskinen March 29, 2019, 10:48 a.m. UTC | #2 
Hi,

On Fri, Mar 29, 2019 at 10:02:20AM +0000, Jose Abreu wrote:
> On 3/27/2019 8:35 PM, Aaro Koskinen wrote:
> > From: Aaro Koskinen <aaro.koskinen@nokia.com>
> > 
> > We always program the maximum DMA buffer size into the receive descriptor,
> > although the allocated size may be less. E.g. with the default MTU size
> > we allocate only 1536 bytes. If somebody sends us a bigger frame, then
> > memory may get corrupted.
> > 
> > Fix by using exact buffer sizes.
> > 
> > Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
> 
> So, I'm seeing that the maximum allowed buffer size that can be
> put in the descriptor changes between enhanced descriptors to
> normal descriptors (8KB vs. 2KB right ?).

There are two size fields, so it's 16KB vs 4 KB.

> Shouldn't stmmac_main know about this limit before trying to init
> descriptors ?

Yes, and that is not a problem.

> We do limit the MTU according to HW version but I would rather
> prefer not having to need to calculate min() values in the
> descriptor code and just use the value as is ...

I don't think the calculation can be avoided, as the passed value can
be bigger than a single field can hold, or less than the maximum.

A.
diff mbox series

Patch

diff --git a/drivers/net/ethernet/stmicro/stmmac/descs_com.h b/drivers/net/ethernet/stmicro/stmmac/descs_com.h
index 40d6356a7e73..3dfb07a78952 100644
--- a/drivers/net/ethernet/stmicro/stmmac/descs_com.h
+++ b/drivers/net/ethernet/stmicro/stmmac/descs_com.h
@@ -29,11 +29,13 @@ 
 /* Specific functions used for Ring mode */
 
 /* Enhanced descriptors */
-static inline void ehn_desc_rx_set_on_ring(struct dma_desc *p, int end)
+static inline void ehn_desc_rx_set_on_ring(struct dma_desc *p, int end,
+					   int bfsize)
 {
-	p->des1 |= cpu_to_le32((BUF_SIZE_8KiB
-			<< ERDES1_BUFFER2_SIZE_SHIFT)
-		   & ERDES1_BUFFER2_SIZE_MASK);
+	if (bfsize == BUF_SIZE_16KiB)
+		p->des1 |= cpu_to_le32((BUF_SIZE_8KiB
+				<< ERDES1_BUFFER2_SIZE_SHIFT)
+			   & ERDES1_BUFFER2_SIZE_MASK);
 
 	if (end)
 		p->des1 |= cpu_to_le32(ERDES1_END_RING);
@@ -59,11 +61,15 @@  static inline void enh_set_tx_desc_len_on_ring(struct dma_desc *p, int len)
 }
 
 /* Normal descriptors */
-static inline void ndesc_rx_set_on_ring(struct dma_desc *p, int end)
+static inline void ndesc_rx_set_on_ring(struct dma_desc *p, int end, int bfsize)
 {
-	p->des1 |= cpu_to_le32(((BUF_SIZE_2KiB - 1)
-				<< RDES1_BUFFER2_SIZE_SHIFT)
-		    & RDES1_BUFFER2_SIZE_MASK);
+	if (bfsize >= BUF_SIZE_2KiB) {
+		int bfsize2;
+
+		bfsize2 = min(bfsize - BUF_SIZE_2KiB + 1, BUF_SIZE_2KiB - 1);
+		p->des1 |= cpu_to_le32((bfsize2 << RDES1_BUFFER2_SIZE_SHIFT)
+			    & RDES1_BUFFER2_SIZE_MASK);
+	}
 
 	if (end)
 		p->des1 |= cpu_to_le32(RDES1_END_RING);
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
index 7fbb6a4dbf51..e061e9f5fad7 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
@@ -296,7 +296,7 @@  static int dwmac4_wrback_get_rx_timestamp_status(void *desc, void *next_desc,
 }
 
 static void dwmac4_rd_init_rx_desc(struct dma_desc *p, int disable_rx_ic,
-				   int mode, int end)
+				   int mode, int end, int bfsize)
 {
 	dwmac4_set_rx_owner(p, disable_rx_ic);
 }
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_descs.c b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_descs.c
index 1d858fdec997..98fa471da7c0 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_descs.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_descs.c
@@ -123,7 +123,7 @@  static int dwxgmac2_get_rx_timestamp_status(void *desc, void *next_desc,
 }
 
 static void dwxgmac2_init_rx_desc(struct dma_desc *p, int disable_rx_ic,
-				  int mode, int end)
+				  int mode, int end, int bfsize)
 {
 	dwxgmac2_set_rx_owner(p, disable_rx_ic);
 }
diff --git a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c
index 5ef91a790f9d..e8855e6adb48 100644
--- a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c
@@ -259,15 +259,19 @@  static int enh_desc_get_rx_status(void *data, struct stmmac_extra_stats *x,
 }
 
 static void enh_desc_init_rx_desc(struct dma_desc *p, int disable_rx_ic,
-				  int mode, int end)
+				  int mode, int end, int bfsize)
 {
+	int bfsize1;
+
 	p->des0 |= cpu_to_le32(RDES0_OWN);
-	p->des1 |= cpu_to_le32(BUF_SIZE_8KiB & ERDES1_BUFFER1_SIZE_MASK);
+
+	bfsize1 = min(bfsize, BUF_SIZE_8KiB);
+	p->des1 |= cpu_to_le32(bfsize1 & ERDES1_BUFFER1_SIZE_MASK);
 
 	if (mode == STMMAC_CHAIN_MODE)
 		ehn_desc_rx_set_on_chain(p);
 	else
-		ehn_desc_rx_set_on_ring(p, end);
+		ehn_desc_rx_set_on_ring(p, end, bfsize);
 
 	if (disable_rx_ic)
 		p->des1 |= cpu_to_le32(ERDES1_DISABLE_IC);
diff --git a/drivers/net/ethernet/stmicro/stmmac/hwif.h b/drivers/net/ethernet/stmicro/stmmac/hwif.h
index 92b8944f26e3..5bb00234d961 100644
--- a/drivers/net/ethernet/stmicro/stmmac/hwif.h
+++ b/drivers/net/ethernet/stmicro/stmmac/hwif.h
@@ -33,7 +33,7 @@  struct dma_extended_desc;
 struct stmmac_desc_ops {
 	/* DMA RX descriptor ring initialization */
 	void (*init_rx_desc)(struct dma_desc *p, int disable_rx_ic, int mode,
-			int end);
+			int end, int bfsize);
 	/* DMA TX descriptor ring initialization */
 	void (*init_tx_desc)(struct dma_desc *p, int mode, int end);
 	/* Invoked by the xmit function to prepare the tx descriptor */
diff --git a/drivers/net/ethernet/stmicro/stmmac/norm_desc.c b/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
index de65bb29feba..c55a9815b394 100644
--- a/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
@@ -135,15 +135,19 @@  static int ndesc_get_rx_status(void *data, struct stmmac_extra_stats *x,
 }
 
 static void ndesc_init_rx_desc(struct dma_desc *p, int disable_rx_ic, int mode,
-			       int end)
+			       int end, int bfsize)
 {
+	int bfsize1;
+
 	p->des0 |= cpu_to_le32(RDES0_OWN);
-	p->des1 |= cpu_to_le32((BUF_SIZE_2KiB - 1) & RDES1_BUFFER1_SIZE_MASK);
+
+	bfsize1 = min(bfsize, BUF_SIZE_2KiB - 1);
+	p->des1 |= cpu_to_le32(bfsize & RDES1_BUFFER1_SIZE_MASK);
 
 	if (mode == STMMAC_CHAIN_MODE)
 		ndesc_rx_set_on_chain(p, end);
 	else
-		ndesc_rx_set_on_ring(p, end);
+		ndesc_rx_set_on_ring(p, end, bfsize);
 
 	if (disable_rx_ic)
 		p->des1 |= cpu_to_le32(RDES1_DISABLE_IC);
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 6a2e1031a62a..4e496cf655f2 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1136,11 +1136,13 @@  static void stmmac_clear_rx_descriptors(struct stmmac_priv *priv, u32 queue)
 		if (priv->extend_desc)
 			stmmac_init_rx_desc(priv, &rx_q->dma_erx[i].basic,
 					priv->use_riwt, priv->mode,
-					(i == DMA_RX_SIZE - 1));
+					(i == DMA_RX_SIZE - 1),
+					priv->dma_buf_sz);
 		else
 			stmmac_init_rx_desc(priv, &rx_q->dma_rx[i],
 					priv->use_riwt, priv->mode,
-					(i == DMA_RX_SIZE - 1));
+					(i == DMA_RX_SIZE - 1),
+					priv->dma_buf_sz);
 }
 
 /**