linux-kernel - [ammarfaizi2-block:dhowells/linux-fs/afs-testing 44/44] include/asm-generic/cmpxchg.h:35:39: sparse: sparse: cast truncates bits from constant value (5e5ee5e5 becomes e5)

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Date:   Sat, 26 Mar 2022 09:50:50 +0800
From:   kernel test robot <lkp@...el.com>
To:     David Howells <dhowells@...hat.com>
Cc:     kbuild-all@...ts.01.org,
        GNU/Weeb Mailing List <gwml@...r.gnuweeb.org>,
        linux-kernel@...r.kernel.org
Subject: [ammarfaizi2-block:dhowells/linux-fs/afs-testing 44/44]
 include/asm-generic/cmpxchg.h:35:39: sparse: sparse: cast truncates bits
 from constant value (5e5ee5e5 becomes e5)

tree:   https://github.com/ammarfaizi2/linux-block dhowells/linux-fs/afs-testing
head:   1eba43e7cea9100a3767c5a7212ec5f1db4db4fd
commit: 1eba43e7cea9100a3767c5a7212ec5f1db4db4fd [44/44] Check for dead timer
config: nios2-randconfig-s032-20220324 (https://download.01.org/0day-ci/archive/20220326/202203260941.OiKX28fM-lkp@intel.com/config)
compiler: nios2-linux-gcc (GCC) 11.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.4-dirty
        # https://github.com/ammarfaizi2/linux-block/commit/1eba43e7cea9100a3767c5a7212ec5f1db4db4fd
        git remote add ammarfaizi2-block https://github.com/ammarfaizi2/linux-block
        git fetch --no-tags ammarfaizi2-block dhowells/linux-fs/afs-testing
        git checkout 1eba43e7cea9100a3767c5a7212ec5f1db4db4fd
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=nios2 SHELL=/bin/bash kernel/time/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@...el.com>


sparse warnings: (new ones prefixed by >>)
   kernel/time/timer.c: note: in included file (through arch/nios2/include/generated/asm/cmpxchg.h, include/asm-generic/atomic.h, arch/nios2/include/generated/asm/atomic.h, ...):
>> include/asm-generic/cmpxchg.h:35:39: sparse: sparse: cast truncates bits from constant value (5e5ee5e5 becomes e5)
>> include/asm-generic/cmpxchg.h:46:40: sparse: sparse: cast truncates bits from constant value (5e5ee5e5 becomes e5e5)

vim +35 include/asm-generic/cmpxchg.h

b4816afa3986704 David Howells 2012-03-28  22  
b4816afa3986704 David Howells 2012-03-28  23  static inline
82b993e8249ae3c Mark Rutland  2021-05-25  24  unsigned long __generic_xchg(unsigned long x, volatile void *ptr, int size)
b4816afa3986704 David Howells 2012-03-28  25  {
b4816afa3986704 David Howells 2012-03-28  26  	unsigned long ret, flags;
b4816afa3986704 David Howells 2012-03-28  27  
b4816afa3986704 David Howells 2012-03-28  28  	switch (size) {
b4816afa3986704 David Howells 2012-03-28  29  	case 1:
b4816afa3986704 David Howells 2012-03-28  30  #ifdef __xchg_u8
b4816afa3986704 David Howells 2012-03-28  31  		return __xchg_u8(x, ptr);
b4816afa3986704 David Howells 2012-03-28  32  #else
b4816afa3986704 David Howells 2012-03-28  33  		local_irq_save(flags);
b4816afa3986704 David Howells 2012-03-28  34  		ret = *(volatile u8 *)ptr;
b4816afa3986704 David Howells 2012-03-28 @35  		*(volatile u8 *)ptr = x;
b4816afa3986704 David Howells 2012-03-28  36  		local_irq_restore(flags);
b4816afa3986704 David Howells 2012-03-28  37  		return ret;
b4816afa3986704 David Howells 2012-03-28  38  #endif /* __xchg_u8 */
b4816afa3986704 David Howells 2012-03-28  39  
b4816afa3986704 David Howells 2012-03-28  40  	case 2:
b4816afa3986704 David Howells 2012-03-28  41  #ifdef __xchg_u16
b4816afa3986704 David Howells 2012-03-28  42  		return __xchg_u16(x, ptr);
b4816afa3986704 David Howells 2012-03-28  43  #else
b4816afa3986704 David Howells 2012-03-28  44  		local_irq_save(flags);
b4816afa3986704 David Howells 2012-03-28  45  		ret = *(volatile u16 *)ptr;
b4816afa3986704 David Howells 2012-03-28 @46  		*(volatile u16 *)ptr = x;
b4816afa3986704 David Howells 2012-03-28  47  		local_irq_restore(flags);
b4816afa3986704 David Howells 2012-03-28  48  		return ret;
b4816afa3986704 David Howells 2012-03-28  49  #endif /* __xchg_u16 */
b4816afa3986704 David Howells 2012-03-28  50  
b4816afa3986704 David Howells 2012-03-28  51  	case 4:
b4816afa3986704 David Howells 2012-03-28  52  #ifdef __xchg_u32
b4816afa3986704 David Howells 2012-03-28  53  		return __xchg_u32(x, ptr);
b4816afa3986704 David Howells 2012-03-28  54  #else
b4816afa3986704 David Howells 2012-03-28  55  		local_irq_save(flags);
b4816afa3986704 David Howells 2012-03-28  56  		ret = *(volatile u32 *)ptr;
b4816afa3986704 David Howells 2012-03-28  57  		*(volatile u32 *)ptr = x;
b4816afa3986704 David Howells 2012-03-28  58  		local_irq_restore(flags);
b4816afa3986704 David Howells 2012-03-28  59  		return ret;
b4816afa3986704 David Howells 2012-03-28  60  #endif /* __xchg_u32 */
b4816afa3986704 David Howells 2012-03-28  61  

:::::: The code at line 35 was first introduced by commit
:::::: b4816afa3986704d1404fc48e931da5135820472 Move the asm-generic/system.h xchg() implementation to asm-generic/cmpxchg.h

:::::: TO: David Howells <dhowells@...hat.com>
:::::: CC: David Howells <dhowells@...hat.com>

-- 
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https://01.org/lkp