Re: sparse false-positive ? (was [linux-next:master 3256/8744] drivers/platform/x86/apple-gmux.c:224:48: sparse: sparse: incorrect type in argument 1 (different address spaces))

[Dan Carpenter <error27@gmail.com>]

On Tue, Apr 04, 2023 at 11:50:17AM +0200, Hans de Goede wrote:
> Dan,
> 
> Can you perhaps help me understand the following sparse warnings,
> they seem like false-positives to me. But I'm not used to
> sparse giving false-positives so I think I might be missing something
> here ?
> 
> On 4/3/23 22:39, kernel test robot wrote:
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> > head:   31bd35b66249699343d2416658f57e97314a433a
> > commit: 0c18184de990e63f708b090bcb9fc6c0fbc427cd [3256/8744] platform/x86: apple-gmux: support MMIO gmux on T2 Macs
> > config: x86_64-randconfig-s023-20230403 (https://download.01.org/0day-ci/archive/20230404/202304040401.IMxt7Ubi-lkp@intel.com/config)
> > compiler: gcc-11 (Debian 11.3.0-8) 11.3.0
> > reproduce:
> >         # apt-get install sparse
> >         # sparse version: v0.6.4-39-gce1a6720-dirty
> >         # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=0c18184de990e63f708b090bcb9fc6c0fbc427cd
> >         git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
> >         git fetch --no-tags linux-next master
> >         git checkout 0c18184de990e63f708b090bcb9fc6c0fbc427cd
> >         # save the config file
> >         mkdir build_dir && cp config build_dir/.config
> >         make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=x86_64 olddefconfig
> >         make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/platform/x86/
> > 
> > If you fix the issue, kindly add following tag where applicable
> > | Reported-by: kernel test robot <lkp@intel.com>
> > | Link: https://lore.kernel.org/oe-kbuild-all/202304040401.IMxt7Ubi-lkp@intel.com/
> > 
> > sparse warnings: (new ones prefixed by >>)
> >>> drivers/platform/x86/apple-gmux.c:224:48: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected void const [noderef] __iomem * @@     got unsigned char [usertype] * @@
> >    drivers/platform/x86/apple-gmux.c:224:48: sparse:     expected void const [noderef] __iomem *
> >    drivers/platform/x86/apple-gmux.c:224:48: sparse:     got unsigned char [usertype] *
> 
> So apple-gmux.c:224 for the commit these sparse warnings are about reads:
> 
> 	u8 gwr = ioread8(gmux_data->iomem_base + GMUX_MMIO_COMMAND_SEND);
> 
> Where gmux_data is a "struct apple_gmux_data *" and the iomem_base member is:
> 
> 	u8 *__iomem iomem_base;
> 

The __iomem should go before the *.

	u8 __iomem *iomem_base;

regards,
dan carpenter