[viro-vfs:headers.unaligned 2/2] include/linux/unaligned.h:119:16: sparse: sparse: cast truncates bits from constant value (aa01a0 becomes a0)

[viro-vfs:headers.unaligned 2/2] include/linux/unaligned.h:119:16: sparse: sparse: cast truncates bits from constant value (aa01a0 becomes a0)

[kernel test robot]

Hi Al,

FYI, the error/warning was bisected to this commit, please ignore it if it's irrelevant.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git headers.unaligned
head:   959598f725aa7721a4bad53c2e997c7255ff32dc
commit: 959598f725aa7721a4bad53c2e997c7255ff32dc [2/2] move asm/unaligned.h to linux/unaligned.h
config: x86_64-randconfig-123-20231214 (https://download.01.org/0day-ci/archive/20231214/202312140955.cqLj4SLn-lkp@intel.com/config)
compiler: clang version 16.0.4 (https://github.com/llvm/llvm-project.git ae42196bc493ffe877a7e3dff8be32035dea4d07)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231214/202312140955.cqLj4SLn-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202312140955.cqLj4SLn-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
   drivers/input/touchscreen/hynitron_cstxxx.c: note: in included file:
>> include/linux/unaligned.h:119:16: sparse: sparse: cast truncates bits from constant value (aa01a0 becomes a0)
>> include/linux/unaligned.h:120:20: sparse: sparse: cast truncates bits from constant value (aa01 becomes 1)
>> include/linux/unaligned.h:119:16: sparse: sparse: cast truncates bits from constant value (ab00d0 becomes d0)
>> include/linux/unaligned.h:120:20: sparse: sparse: cast truncates bits from constant value (ab00 becomes 0)

vim +119 include/linux/unaligned.h

803f4e1eab7a89 include/asm-generic/unaligned.h Arnd Bergmann 2021-05-08  116  
803f4e1eab7a89 include/asm-generic/unaligned.h Arnd Bergmann 2021-05-08  117  static inline void __put_unaligned_le24(const u32 val, u8 *p)
803f4e1eab7a89 include/asm-generic/unaligned.h Arnd Bergmann 2021-05-08  118  {
803f4e1eab7a89 include/asm-generic/unaligned.h Arnd Bergmann 2021-05-08 @119  	*p++ = val;
803f4e1eab7a89 include/asm-generic/unaligned.h Arnd Bergmann 2021-05-08 @120  	*p++ = val >> 8;
803f4e1eab7a89 include/asm-generic/unaligned.h Arnd Bergmann 2021-05-08  121  	*p++ = val >> 16;
803f4e1eab7a89 include/asm-generic/unaligned.h Arnd Bergmann 2021-05-08  122  }
803f4e1eab7a89 include/asm-generic/unaligned.h Arnd Bergmann 2021-05-08  123  

:::::: The code at line 119 was first introduced by commit
:::::: 803f4e1eab7a8938ba3a3c30dd4eb5e9eeef5e63 asm-generic: simplify asm/unaligned.h

:::::: TO: Arnd Bergmann <arnd@arndb.de>
:::::: CC: Arnd Bergmann <arnd@arndb.de>

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [viro-vfs:headers.unaligned 2/2] include/linux/unaligned.h:119:16: sparse: sparse: cast truncates bits from constant value (aa01a0 becomes a0)

[Al Viro]

On Thu, Dec 14, 2023 at 09:25:30AM +0800, kernel test robot wrote:
> Hi Al,
> 
> FYI, the error/warning was bisected to this commit, please ignore it if it's irrelevant.

It is, unless the mainline does *not* have equivalent warnings refering
include/asm-generic/unaligned.h instead of include/linux/unaligned.h