[PATCH] net: pxa168_eth: avoid using signed char for bitops

Antoine Tenart
2014-10-03T15:07:03Z

On Fri, Oct 03, 2014 at 05:01:54PM +0200, Antoine Tenart wrote:
> Signedness bugs may occur when using signed char for bitops,
> depending on if the highest bit is ever used.
>
> Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
>
> Dan reported a static checker warning:
> http://marc.info/?l=kernel-janitors&m=141218246222535&w=2
>
> This patch fixes it. Instead of using sa->sa_data we now use
> dev->dev_addr (of type unsigned char *) to avoid possible
> signedness issues.

Well, this patch shouldn't be in this thread. I'm resending it.
Sorry for the noise.

Antoine

>
> drivers/net/ethernet/marvell/pxa168_eth.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/ethernet/marvell/pxa168_eth.c b/drivers/net/ethernet/marvell/pxa168_eth.c
> index 24de41231593..c3b209cd0660 100644
> --- a/drivers/net/ethernet/marvell/pxa168_eth.c
> +++ b/drivers/net/ethernet/marvell/pxa168_eth.c
> @@ -634,12 +634,12 @@ static int pxa168_eth_set_mac_address(struct net_device *dev, void *addr)
> memcpy(oldMac, dev->dev_addr, ETH_ALEN);
> memcpy(dev->dev_addr, sa->sa_data, ETH_ALEN);
>
> - mac_h = sa->sa_data[0] << 24;
> - mac_h |= sa->sa_data[1] << 16;
> - mac_h |= sa->sa_data[2] << 8;
> - mac_h |= sa->sa_data[3];
> - mac_l = sa->sa_data[4] << 8;
> - mac_l |= sa->sa_data[5];
> + mac_h = dev->dev_addr[0] << 24;
> + mac_h |= dev->dev_addr[1] << 16;
> + mac_h |= dev->dev_addr[2] << 8;
> + mac_h |= dev->dev_addr[3];
> + mac_l = dev->dev_addr[4] << 8;
> + mac_l |= dev->dev_addr[5];
> wrl(pep, MAC_ADDR_HIGH, mac_h);
> wrl(pep, MAC_ADDR_LOW, mac_l);
>
> --
> 1.9.1
>

--
Antoine T?nart, Free Electrons
Embedded Linux, Kernel and Android engineering