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

["bhe@redhat.com" <bhe@redhat.com>]

On 07/17/23 at 07:05am, Liu, Yujie wrote:
> 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.

No, your process may need be improved.

On linus's master branch, you can pass compiling on
drivers/clk/clk-fixed-mmio.o, but you absolutely will fail during linking
stage. As I have explained, ioremap()/iounmap()/ioremap_xx() are all
defined in arch/s390/pci/pci.c. Setting CONFIG_PCI=n will make you not
be able to find the implementation of ioremap()/iounmap(). Don't you
finish the whole building process of kernel image and modules?

Please see below building log, the linking is failed. I got a new s390x
machine, and git clone linus's tree and build with randconfig from this
lkp report. 

When I made below patch and tested, I also only git clone linus's latest
kernel tree. I didn't apply any patch. The current lkp report and your
checking could be misleading.

[PATCH 0/8] Make several Kconfig options depend on HAS_IOMEM
https://lore.kernel.org/all/20230707135852.24292-1-bhe@redhat.com,

=====
  AR      drivers/iio/built-in.a
  AR      drivers/built-in.a
  AR      built-in.a
  AR      vmlinux.a
  LD      vmlinux.o
  OBJCOPY modules.builtin.modinfo
  GEN     modules.builtin
  MODPOST vmlinux.symvers
  UPD     include/generated/utsversion.h
  CC      init/version-timestamp.o
  LD      .tmp_vmlinux.kallsyms1
ld: drivers/clk/clk-fixed-mmio.o: in function `fixed_mmio_clk_setup':
clk-fixed-mmio.c:(.text+0x44): undefined reference to `of_iomap'
ld: clk-fixed-mmio.c:(.text+0x9c): undefined reference to `iounmap'
ld: drivers/pcmcia/cistpl.o: in function `set_cis_map':
cistpl.c:(.text+0x52a): undefined reference to `ioremap'
ld: cistpl.c:(.text+0x602): undefined reference to `iounmap'
ld: cistpl.c:(.text+0x650): undefined reference to `iounmap'
ld: cistpl.c:(.text+0x668): undefined reference to `ioremap'
ld: drivers/pcmcia/cistpl.o: in function `release_cis_mem':
cistpl.c:(.text+0x85c): undefined reference to `iounmap'
make[2]: *** [scripts/Makefile.vmlinux:36: vmlinux] Error 1
make[1]: *** [/root/linux/Makefile:1238: vmlinux] Error 2
make: *** [Makefile:234: __sub-make] Error 2