diff mbox

r8169: fix invalid register dump

Message ID 3465288.NFVErF5E7l@al
State Changes Requested, archived
Delegated to: David Miller
Headers show

Commit Message

Peter Wu Aug. 14, 2013, 1:12 p.m. UTC 
On Wednesday 14 August 2013 00:20:38 Francois Romieu wrote:
> > -     memcpy_fromio(p, tp->mmio_addr, regs->len);
> > +     for (i = 0; i < regs->len - 4; i += 4)
> > +             memcpy_fromio(bytes + i, tp->mmio_addr + i, 4);
> 
> regs->len is u32. regs->len - 4 should not underflow on normal situation but
> it's a bit sloppy.

Heh, I forgot about that case. Fixed it in the below patch. By the way,
have you observed similar behavior on other hardware?

Thanks,
Peter
--
From: Peter Wu <lekensteyn@gmail.com>

For some reason, my PCIe RTL8111E onboard NIC on a GA-Z68X-UD3H-B3
motherboard reads as FFs when reading from MMIO with a block size
larger than 7. Therefore change to reading blocks of four bytes.

Signed-off-by: Peter Wu <lekensteyn@gmail.com>
---
 drivers/net/ethernet/realtek/r8169.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

Comments

Francois Romieu Aug. 14, 2013, 7:58 p.m. UTC | #1 
Peter Wu <lekensteyn@gmail.com> :
[...]
> Heh, I forgot about that case. Fixed it in the below patch. By the way,
> have you observed similar behavior on other hardware?

Notwithstanding really old PCI adapters - sometimes - none that I remember of.

[...]
> diff --git a/drivers/net/ethernet/realtek/r8169.c b/drivers/net/ethernet/realtek/r8169.c
> index b5eb419..d367763 100644
> --- a/drivers/net/ethernet/realtek/r8169.c
> +++ b/drivers/net/ethernet/realtek/r8169.c
> @@ -1897,12 +1897,19 @@ static void rtl8169_get_regs(struct net_device *dev, struct ethtool_regs *regs,
>  			     void *p)
>  {
>  	struct rtl8169_private *tp = netdev_priv(dev);
> +	char *bytes = p;
> +	int i;
>  
>  	if (regs->len > R8169_REGS_SIZE)
>  		regs->len = R8169_REGS_SIZE;
>  
>  	rtl_lock_work(tp);
> -	memcpy_fromio(p, tp->mmio_addr, regs->len);
> +	if (regs->len >= 4) {
> +		for (i = 0; i < regs->len - 4; i += 4)
> +			memcpy_fromio(bytes + i, tp->mmio_addr + i, 4);
> +	}
> +	if (i < regs->len)

Comparison with random stack stuff when regs->len < 4. :o/
diff mbox

Patch

diff --git a/drivers/net/ethernet/realtek/r8169.c b/drivers/net/ethernet/realtek/r8169.c
index b5eb419..d367763 100644
--- a/drivers/net/ethernet/realtek/r8169.c
+++ b/drivers/net/ethernet/realtek/r8169.c
@@ -1897,12 +1897,19 @@  static void rtl8169_get_regs(struct net_device *dev, struct ethtool_regs *regs,
 			     void *p)
 {
 	struct rtl8169_private *tp = netdev_priv(dev);
+	char *bytes = p;
+	int i;
 
 	if (regs->len > R8169_REGS_SIZE)
 		regs->len = R8169_REGS_SIZE;
 
 	rtl_lock_work(tp);
-	memcpy_fromio(p, tp->mmio_addr, regs->len);
+	if (regs->len >= 4) {
+		for (i = 0; i < regs->len - 4; i += 4)
+			memcpy_fromio(bytes + i, tp->mmio_addr + i, 4);
+	}
+	if (i < regs->len)
+		memcpy_fromio(bytes + i, tp->mmio_addr + i, regs->len - i);
 	rtl_unlock_work(tp);
 }