Hi Geert-san,
> From: Geert Uytterhoeven, Sent: Tuesday, October 25, 2022 12:28 AM
> To: kernel test robot <lkp@xxxxxxxxx>
> Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>; davem@xxxxxxxxxxxxx; edumazet@xxxxxxxxxx; kuba@xxxxxxxxxx;
> pabeni@xxxxxxxxxx; robh+dt@xxxxxxxxxx; krzysztof.kozlowski+dt@xxxxxxxxxx; kbuild-all@xxxxxxxxxxxx;
> netdev@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-renesas-soc@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v4 2/3] net: ethernet: renesas: Add Ethernet Switch driver
>
> On Wed, Oct 19, 2022 at 1:17 PM kernel test robot <lkp@xxxxxxxxx> wrote:
> > I love your patch! Perhaps something to improve:
> >
> > [auto build test WARNING on net-next/master]
> > [also build test WARNING on net/master robh/for-next linus/master v6.1-rc1 next-20221019]
> > [If your patch is applied to the wrong git tree, kindly drop us a note.
> > And when submitting patch, we suggest to use '--base' as documented in
> >
<snip>
> > git checkout f310f8cc37dfb090cfb06ae38530276327569464
> > # save the config file
> > mkdir build_dir && cp config build_dir/.config
> > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=m68k SHELL=/bin/bash
> drivers/net/
> >
> > If you fix the issue, kindly add following tag where applicable
> > | Reported-by: kernel test robot <lkp@xxxxxxxxx>
> >
> > All warnings (new ones prefixed by >>):
> >
> > drivers/net/ethernet/renesas/rswitch.c: In function 'rswitch_ext_desc_get_dptr':
> > >> drivers/net/ethernet/renesas/rswitch.c:355:71: warning: left shift count >= width of type [-Wshift-count-overflow]
> > 355 | return __le32_to_cpu(desc->dptrl) | (dma_addr_t)(desc->dptrh) << 32;
> > | ^~
> > drivers/net/ethernet/renesas/rswitch.c: In function 'rswitch_ext_ts_desc_get_dptr':
> > drivers/net/ethernet/renesas/rswitch.c:367:71: warning: left shift count >= width of type [-Wshift-count-overflow]
> > 367 | return __le32_to_cpu(desc->dptrl) | (dma_addr_t)(desc->dptrh) << 32;
> > | ^~
> >
> >
> > vim +355 drivers/net/ethernet/renesas/rswitch.c
> >
> > 352
> > 353 static dma_addr_t rswitch_ext_desc_get_dptr(struct rswitch_ext_desc *desc)
> > 354 {
> > > 355 return __le32_to_cpu(desc->dptrl) | (dma_addr_t)(desc->dptrh) << 32;
>
> A simple fix would be to replace the cast to "dma_addr_t" by a cast to "u64".
> A more convoluted fix would be:
>
> dma_addr_t dma;
>
> dma = __le32_to_cpu(desc->dptrl);
> if (IS_ENABLED(CONFIG_ARCH_DMA_ADDR_T_64BIT))
> dma |= (u64)desc->dptrh << 32;
> return dma;
>
> Looking at the gcc compiler output, the both cases are optimized to the
> exact same code, for both arm32 and arm64, so I'd go for the simple fix.
I got it. I'll fix this by a cast to "u64".
> BTW, if struct rswitch_ext_desc would just extend struct rswitch_desc,
> you could use rswitch_ext_desc_get_dptr() for both.
Yes, all rswitch_xxx_desc just extend struct rswitch_desc.
So, I'll modify this function like below:
---
/* All struct rswitch_xxx_desc just extend struct rswitch_desc, so that
* we can use rswitch_desc_get_dptr() for them.
*/
static dma_addr_t rswitch_desc_get_dptr(void *_desc)
{
struct rswitch_desc *desc = _desc;
return __le32_to_cpu(desc->dptrl) | (u64)(desc->dptrh) << 32;
}
---
Best regards,
Yoshihiro Shimoda
