Re: [kbuild-all] Re: include/linux/atomic-arch-fallback.h:60:32: error: implicit declaration of function 'arch_cmpxchg64'; did you mean 'arch_cmpxchg'?

[Chen, Rong A]

On 7/12/2021 10:31 PM, Mark Rutland wrote:
> On Sun, Jul 11, 2021 at 06:44:47AM +0800, kernel test robot wrote:
> > Hi Mark,
> >
> > FYI, the error/warning still remains.
>
> I thought we'd already identified that this was an existing bug, and all that
> has changed is the specific error that manifests.

Hi Mark,

Thanks for the feedback, We won't report the error again.

Best Regards,
Rong Chen

> In v5.13 this would fail with:
>
> |   CC      drivers/iommu/io-pgtable-arm.o
> | In file included from ./include/linux/atomic.h:84,
> |                  from drivers/iommu/io-pgtable-arm.c:12:
> | drivers/iommu/io-pgtable-arm.c: In function 'arm_lpae_install_table':
> | ./include/linux/atomic-fallback.h:60:27: error: implicit declaration of function 'cmpxchg64'; did you mean 'cmpxchg'? [-Werror=implicit-function-declaration]
> |    60 | #define cmpxchg64_relaxed cmpxchg64
> |       |                           ^~~~~~~~~
> | drivers/iommu/io-pgtable-arm.c:320:8: note: in expansion of macro 'cmpxchg64_relaxed'
> |   320 |  old = cmpxchg64_relaxed(ptep, curr, new);
> |       |        ^~~~~~~~~~~~~~~~~
>
> ... which has the same underlying problem -- the architecture has not provided
> a cmpxchg64() implementation, but the IO pagetable code depends upon
> cmpxchg64().
>
> Thanks,
> Mark.
>
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > head:   1e16624d7b4376797ede36e3c955375cf0f23298
> > commit: bccf1ec369ac126b0997d01a6e1deae00e2cf6b3 locking/atomics: atomic-instrumented: simplify ifdeffery
> > date:   6 weeks ago
> > config: arc-allyesconfig (attached as .config)
> > compiler: arceb-elf-gcc (GCC) 9.3.0
> > reproduce (this is a W=1 build):
> >          wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> >          chmod +x ~/bin/make.cross
> >          # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=bccf1ec369ac126b0997d01a6e1deae00e2cf6b3
> >          git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> >          git fetch --no-tags linus master
> >          git checkout bccf1ec369ac126b0997d01a6e1deae00e2cf6b3
> >          # save the attached .config to linux build tree
> >          COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arc
> >
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> >
> > All errors (new ones prefixed by >>):
> >
> >     In file included from include/linux/atomic.h:80,
> >                      from drivers/iommu/io-pgtable-arm.c:12:
> >     drivers/iommu/io-pgtable-arm.c: In function 'arm_lpae_install_table':
> > > > include/linux/atomic-arch-fallback.h:60:32: error: implicit declaration of function 'arch_cmpxchg64'; did you mean 'arch_cmpxchg'? [-Werror=implicit-function-declaration]
> >        60 | #define arch_cmpxchg64_relaxed arch_cmpxchg64
> >           |                                ^~~~~~~~~~~~~~
> >     include/asm-generic/atomic-instrumented.h:1261:2: note: in expansion of macro 'arch_cmpxchg64_relaxed'
> >      1261 |  arch_cmpxchg64_relaxed(__ai_ptr, __VA_ARGS__); \
> >           |  ^~~~~~~~~~~~~~~~~~~~~~
> >     drivers/iommu/io-pgtable-arm.c:320:8: note: in expansion of macro 'cmpxchg64_relaxed'
> >       320 |  old = cmpxchg64_relaxed(ptep, curr, new);
> >           |        ^~~~~~~~~~~~~~~~~
> >     cc1: some warnings being treated as errors
> >
> >
> > vim +60 include/linux/atomic-arch-fallback.h
> >
> > 37f8173dd84936 Peter Zijlstra 2020-01-24  56
> > 37f8173dd84936 Peter Zijlstra 2020-01-24  57  #ifndef arch_cmpxchg64_relaxed
> > 37f8173dd84936 Peter Zijlstra 2020-01-24  58  #define arch_cmpxchg64_acquire arch_cmpxchg64
> > 37f8173dd84936 Peter Zijlstra 2020-01-24  59  #define arch_cmpxchg64_release arch_cmpxchg64
> > 29f006fdefe6f8 Peter Zijlstra 2020-08-29 @60  #define arch_cmpxchg64_relaxed arch_cmpxchg64
> > 37f8173dd84936 Peter Zijlstra 2020-01-24  61  #else /* arch_cmpxchg64_relaxed */
> > 37f8173dd84936 Peter Zijlstra 2020-01-24  62
> >
> > :::::: The code at line 60 was first introduced by commit
> > :::::: 29f006fdefe6f88abde973a0b0f20d2704e93fd4 asm-generic/atomic: Add try_cmpxchg() fallbacks
> >
> > :::::: TO: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> > :::::: CC: Ingo Molnar <mingo@xxxxxxxxxx>
> >
> > ---
> > 0-DAY CI Kernel Test Service, Intel Corporation
> > https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
>
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