On Fri, Jun 19, 2020 at 11:38:59AM +0300, Andy Shevchenko wrote:

On Fri, Jun 19, 2020 at 10:02 AM Syed Nayyar Waris [off-list ref] wrote:

...

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config: sparc64-randconfig-s032-20200615 (attached as .config)
compiler: sparc64-linux-gcc (GCC) 9.3.0
reproduce:
        # apt-get install sparse
        # sparse version: v0.6.2-rc1-3-g55607964-dirty
        # save the attached .config to linux build tree
        make W=1 C=1 ARCH=sparc64 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__'

...

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sparse warnings: (new ones prefixed by >>)

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include/linux/bitmap.h:639:45: sparse: sparse: shift too big (64) for type unsigned long
include/linux/bitmap.h:639:45: sparse: sparse: shift too big (64) for type unsigned long

   include/linux/bitmap.h:594:63: sparse: sparse: shift too big (64) for type unsigned long

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include/linux/bitmap.h:639:45: sparse: sparse: shift too big (64) for type unsigned long
include/linux/bitmap.h:638:17: sparse: sparse: invalid access past the end of 'old' (8 8)

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It seems to me that to reproduce this warning, I have to use the
sparc64 compiler. I have installed 'sparc64-linux-gnu-gcc' on my
computer.

Sparse is not a compiler.

On x86_64:

  CHECK   drivers/gpio/gpio-xilinx.c
  include/linux/bitmap.h:639:45: warning: shift too big (64) for type unsigned long
  include/linux/bitmap.h:639:45: warning: shift too big (64) for type unsigned long
  include/linux/bitmap.h:594:63: warning: shift too big (64) for type unsigned long
  include/linux/bitmap.h:639:45: warning: shift too big (64) for type unsigned long
  include/linux/bitmap.h:638:17: warning: invalid access past the end of 'old' (8 8)

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I have to specify that this compiler needs to be used for build
process. How/ Where do I specify this?

I have downloaded the config.gz (has config file) and placed it at the
root of the linux kernel project tree. But the Makefile STILL has
'gcc' as the compiler. When I build, it is the 'gcc' compiler being
used and not 'sparc64-linux-gnu-gcc'. I know I can manually change the
Makefile to use sparc64 compiler, but I think there must be some more
elegant way to do this, perhaps using make menuconfig?

If you wish to run a compilation, download a compiler from [1], and,
after adding its bin/ folder to PATH, run
make CROSS_COMPILE=sparc64-linux- ARCH=sparc64 ... # first generate .config

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Kindly illuminate as to how shall I reproduce the compiler warning.

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803024b6c8a375 Syed Nayyar Waris      2020-06-15 @638           map[index + 1] &= ~BITMAP_LAST_WORD_MASK(start + nbits);
803024b6c8a375 Syed Nayyar Waris      2020-06-15 @639           map[index + 1] |= (value >> space);

Hmm... I think I sent a reply [2] where I explained how space can be
64. Do you agree with analysis?

[1]: https://mirrors.edge.kernel.org/pub/tools/crosstool/
[2]: https://lore.kernel.org/lkml/20200616081428.GP2428291@smile.fi.intel.com/ (local)

-- 
With Best Regards,
Andy Shevchenko



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