arch/sparc/include/asm/cmpxchg_64.h:161:55: sparse: sparse: cast truncates bits from constant value (ffffffffe0f510cc becomes cc)

From: kernel test robot
Date: Tue Aug 11 2020 - 21:50:20 EST


tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: fb893de323e2d39f7a1f6df425703a2edbdf56ea
commit: 47e4937a4a7ca4184fd282791dfee76c6799966a erofs: move erofs out of staging
date: 12 months ago
config: sparc64-randconfig-s032-20200812 (attached as .config)
compiler: sparc64-linux-gcc (GCC) 9.3.0
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: v0.6.2-168-g9554805c-dirty
git checkout 47e4937a4a7ca4184fd282791dfee76c6799966a
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=sparc64

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


sparse warnings: (new ones prefixed by >>)

fs/erofs/utils.c: note: in included file (through arch/sparc/include/asm/cmpxchg.h, arch/sparc/include/asm/atomic_64.h, arch/sparc/include/asm/atomic.h, ...):
>> arch/sparc/include/asm/cmpxchg_64.h:161:55: sparse: sparse: cast truncates bits from constant value (ffffffffe0f510cc becomes cc)
--
fs/erofs/zdata.c: note: in included file (through arch/sparc/include/asm/cmpxchg.h, arch/sparc/include/asm/atomic_64.h, arch/sparc/include/asm/atomic.h, ...):
>> arch/sparc/include/asm/cmpxchg_64.h:161:55: sparse: sparse: cast truncates bits from constant value (ffffffffe0f510cc becomes cc)
arch/sparc/include/asm/cmpxchg_64.h:161:50: sparse: sparse: cast truncates bits from constant value (5f0ecafe becomes fe)
arch/sparc/include/asm/cmpxchg_64.h:161:50: sparse: sparse: cast truncates bits from constant value (5f0ecafe becomes fe)
arch/sparc/include/asm/cmpxchg_64.h:161:55: sparse: sparse: cast truncates bits from constant value (5f0edead becomes ad)

vim +161 arch/sparc/include/asm/cmpxchg_64.h

d550bbd40c0e10 David Howells 2012-03-28 155
d550bbd40c0e10 David Howells 2012-03-28 156 static inline unsigned long
d550bbd40c0e10 David Howells 2012-03-28 157 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
d550bbd40c0e10 David Howells 2012-03-28 158 {
d550bbd40c0e10 David Howells 2012-03-28 159 switch (size) {
a12ee2349312d7 Babu Moger 2017-05-24 160 case 1:
a12ee2349312d7 Babu Moger 2017-05-24 @161 return __cmpxchg_u8(ptr, old, new);
d550bbd40c0e10 David Howells 2012-03-28 162 case 4:
d550bbd40c0e10 David Howells 2012-03-28 163 return __cmpxchg_u32(ptr, old, new);
d550bbd40c0e10 David Howells 2012-03-28 164 case 8:
d550bbd40c0e10 David Howells 2012-03-28 165 return __cmpxchg_u64(ptr, old, new);
d550bbd40c0e10 David Howells 2012-03-28 166 }
d550bbd40c0e10 David Howells 2012-03-28 167 __cmpxchg_called_with_bad_pointer();
d550bbd40c0e10 David Howells 2012-03-28 168 return old;
d550bbd40c0e10 David Howells 2012-03-28 169 }
d550bbd40c0e10 David Howells 2012-03-28 170

:::::: The code at line 161 was first introduced by commit
:::::: a12ee2349312d7112b9b7c6ac2e70c5ec2ca334e arch/sparc: Introduce cmpxchg_u8 SPARC

:::::: TO: Babu Moger <babu.moger@xxxxxxxxxx>
:::::: CC: David S. Miller <davem@xxxxxxxxxxxxx>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx

Attachment: .config.gz
Description: application/gzip