Re: [akpm-mm:mm-unstable 93/173] drivers/clk/clk-fixed-mmio.c:33:2: error: call to undeclared function 'iounmap'; ISO C99 and later do not support implicit function declarations

["Liu, Yujie" <yujie.liu@intel.com>]

Hi Baoquan,

On Fri, 2023-07-14 at 07:59 +0800, Baoquan He wrote:
> > 
> > In file included from ./include/linux/io.h:13,
> >                  from drivers/clk/clk-fixed-mmio.c:13:
> > drivers/clk/clk-fixed-mmio.c: In function 'fixed_mmio_clk_setup':
> > ./arch/s390/include/asm/io.h:29:17: error: implicit declaration of function 'iounmap'; did you mean 'vunmap'? [-Werror=implicit-function-declaration]
> >    29 | #define iounmap iounmap
> >       |                 ^~~~~~~
> > drivers/clk/clk-fixed-mmio.c:33:9: note: in expansion of macro 'iounmap'
> >    33 |         iounmap(base);
> >       |         ^~~~~~~
> 
> These iorempa/iounmap not defined or declared are not related to my
> patches. S390 could set CONFIG_PCI=n, however its ioremap/iounmap code
> are all defined in arch/s390/pci/pci.c. Means its ioremap/iounmap code
> depends on CONFIG_PCI enabling. So those drivers invoking iomem
> functions, (e.g ioremap(), devm_ioremap(), etc) all will be failed to
> build if CONFIG_PCI=n on s390.
> 
> All these errors have been fixed in my another patchset.
> 
> https://lore.kernel.org/all/20230707135852.24292-1-bhe@redhat.com/T/#u

Sorry for the duplicate reports and late reply.

We searched the log of kernel test robot and got the following clues
for this case:

This is a randconfig build test, so the kconfig happened to set
CONFIG_PCI=n and CONFIG_COMMON_CLK_FIXED_MMIO=y, and it is good to
build the clk-fixed-mmio driver in such case before, but it raises a
build error after applying your patches, so the bot thought that a new
build error was introduced and sent reports to you.

== without the patches (v6.5-rc1 as example) ==

$ git checkout v6.5-rc1
HEAD is now at 06c2afb862f9 Linux 6.5-rc1

$ grep -e CONFIG_PCI -e CONFIG_COMMON_CLK_FIXED_MMIO .config
# CONFIG_PCI is not set
CONFIG_COMMON_CLK_FIXED_MMIO=y

$ COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross LLVM_IAS=1 W=1 ARCH=s390 drivers/clk/clk-fixed-mmio.o
...

$ file drivers/clk/clk-fixed-mmio.o
drivers/clk/clk-fixed-mmio.o: ELF 64-bit MSB relocatable, IBM S/390, version 1 (SYSV), not stripped

== with the patches ==

$ git checkout b0f683e34a5b
HEAD is now at b0f683e34a5b s390: mm: convert to GENERIC_IOREMAP

$ grep -e CONFIG_PCI -e CONFIG_COMMON_CLK_FIXED_MMIO .config
# CONFIG_PCI is not set
CONFIG_COMMON_CLK_FIXED_MMIO=y

$ COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ./make.cross LLVM_IAS=1 W=1 ARCH=s390 drivers/clk/clk-fixed-mmio.o
...
drivers/clk/clk-fixed-mmio.c:33:2: error: call to undeclared function 'iounmap'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
   33 |         iounmap(base);
      |         ^
./arch/s390/include/asm/io.h:29:17: note: expanded from macro 'iounmap'
   29 | #define iounmap iounmap
      |                 ^
drivers/clk/clk-fixed-mmio.c:33:2: note: did you mean 'vunmap'?
./arch/s390/include/asm/io.h:29:17: note: expanded from macro 'iounmap'
   29 | #define iounmap iounmap
      |                 ^
./include/linux/vmalloc.h:167:13: note: 'vunmap' declared here
  167 | extern void vunmap(const void *addr);
      |             ^
12 warnings and 1 error generated.
make[4]: *** [scripts/Makefile.build:243: drivers/clk/clk-fixed-mmio.o] Error 1
make[3]: *** [scripts/Makefile.build:477: drivers/clk] Error 2
make[3]: Target 'drivers/clk/clk-fixed-mmio.o' not remade because of errors.
make[2]: *** [scripts/Makefile.build:477: drivers] Error 2
make[2]: Target 'drivers/clk/clk-fixed-mmio.o' not remade because of errors.
make[1]: *** [/home/yujie/linux/Makefile:2020: .] Error 2
make[1]: Target 'drivers/clk/clk-fixed-mmio.o' not remade because of errors.
make: *** [Makefile:234: __sub-make] Error 2
make: Target 'drivers/clk/clk-fixed-mmio.o' not remade because of errors.


After applying the patchset at
https://lore.kernel.org/all/20230707135852.24292-1-bhe@redhat.com,
above situation cannot happen anymore because CONFIG_PCI and
CONFIG_COMMON_CLK_FIXED_MMIO can only be both enabled or both disabled,
so the issue has been resolved.

Best Regards,
Yujie