drivers/input/touchscreen/ads7846.c:705:24: warning: taking address of packed member 'data' of class or structure 'ads7846_buf' may result in an unaligned pointer value

[kernel test robot <lkp@intel.com>]

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tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   5e321ded302da4d8c5d5dd953423d9b748ab3775
commit: 6965eece2a89c3f1d00881c6052ee1e987870c08 Input: ads7846 - convert to one message
date:   3 months ago
config: mips-randconfig-r026-20210504 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 8f5a2a5836cc8e4c1def2bdeb022e7b496623439)
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
        # install mips cross compiling tool for clang build
        # apt-get install binutils-mips-linux-gnu
        # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6965eece2a89c3f1d00881c6052ee1e987870c08
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout 6965eece2a89c3f1d00881c6052ee1e987870c08
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=mips 

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

All warnings (new ones prefixed by >>):

   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from drivers/input/touchscreen/ads7846.c:20:
   In file included from include/linux/sched.h:12:
   In file included from ./arch/mips/include/generated/asm/current.h:1:
   In file included from include/asm-generic/current.h:5:
   In file included from include/linux/thread_info.h:38:
   In file included from arch/mips/include/asm/thread_info.h:16:
   In file included from arch/mips/include/asm/processor.h:14:
   In file included from include/linux/atomic.h:7:
   arch/mips/include/asm/atomic.h:257:1: warning: converting the result of '<<' to a boolean always evaluates to true [-Wtautological-constant-compare]
   ATOMIC_SIP_OP(atomic, int, subu, ll, sc)
   ^
   arch/mips/include/asm/atomic.h:251:7: note: expanded from macro 'ATOMIC_SIP_OP'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro '__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from drivers/input/touchscreen/ads7846.c:20:
   In file included from include/linux/sched.h:12:
   In file included from ./arch/mips/include/generated/asm/current.h:1:
   In file included from include/asm-generic/current.h:5:
   In file included from include/linux/thread_info.h:38:
   In file included from arch/mips/include/asm/thread_info.h:16:
   In file included from arch/mips/include/asm/processor.h:14:
   In file included from include/linux/atomic.h:7:
   arch/mips/include/asm/atomic.h:261:1: warning: converting the result of '<<' to a boolean always evaluates to true [-Wtautological-constant-compare]
   ATOMIC_SIP_OP(atomic64, s64, dsubu, lld, scd)
   ^
   arch/mips/include/asm/atomic.h:251:7: note: expanded from macro 'ATOMIC_SIP_OP'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro '__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from drivers/input/touchscreen/ads7846.c:20:
   In file included from include/linux/sched.h:14:
   In file included from include/linux/pid.h:5:
   In file included from include/linux/rculist.h:11:
   In file included from include/linux/rcupdate.h:29:
   In file included from include/linux/lockdep.h:14:
   In file included from include/linux/smp.h:15:
   In file included from include/linux/smp_types.h:5:
   include/linux/llist.h:222:9: warning: converting the result of '<<' to a boolean always evaluates to true [-Wtautological-constant-compare]
           return xchg(&head->first, NULL);
                  ^
   arch/mips/include/asm/cmpxchg.h:102:7: note: expanded from macro 'xchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro '__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from drivers/input/touchscreen/ads7846.c:20:
   In file included from include/linux/sched.h:14:
   In file included from include/linux/pid.h:5:
   In file included from include/linux/rculist.h:11:
   In file included from include/linux/rcupdate.h:29:
   In file included from include/linux/lockdep.h:27:
   include/linux/debug_locks.h:17:9: warning: converting the result of '<<' to a boolean always evaluates to true [-Wtautological-constant-compare]
           return xchg(&debug_locks, 0);
                  ^
   arch/mips/include/asm/cmpxchg.h:102:7: note: expanded from macro 'xchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro '__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from drivers/input/touchscreen/ads7846.c:31:
   In file included from include/linux/spi/spi.h:14:
   In file included from include/linux/scatterlist.h:8:
   In file included from include/linux/mm.h:33:
   In file included from include/linux/pgtable.h:6:
   arch/mips/include/asm/pgtable.h:210:3: warning: converting the result of '<<' to a boolean always evaluates to true [-Wtautological-constant-compare]
                   cmpxchg64(&buddy->pte, 0, _PAGE_GLOBAL);
                   ^
   arch/mips/include/asm/cmpxchg.h:220:2: note: expanded from macro 'cmpxchg64'
           cmpxchg((ptr), (o), (n));                                       \
           ^
   arch/mips/include/asm/cmpxchg.h:194:7: note: expanded from macro 'cmpxchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro '__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
   In file included from drivers/input/touchscreen/ads7846.c:31:
   In file included from include/linux/spi/spi.h:14:
   In file included from include/linux/scatterlist.h:8:
   In file included from include/linux/mm.h:33:
   In file included from include/linux/pgtable.h:6:
   arch/mips/include/asm/pgtable.h:210:3: warning: converting the result of '<<' to a boolean always evaluates to true [-Wtautological-constant-compare]
   arch/mips/include/asm/cmpxchg.h:220:2: note: expanded from macro 'cmpxchg64'
           cmpxchg((ptr), (o), (n));                                       \
           ^
   arch/mips/include/asm/cmpxchg.h:204:7: note: expanded from macro 'cmpxchg'
           if (!__SYNC_loongson3_war)                                      \
                ^
   arch/mips/include/asm/sync.h:147:34: note: expanded from macro '__SYNC_loongson3_war'
   # define __SYNC_loongson3_war   (1 << 31)
                                      ^
>> drivers/input/touchscreen/ads7846.c:705:24: warning: taking address of packed member 'data' of class or structure 'ads7846_buf' may result in an unaligned pointer value [-Waddress-of-packed-member]
           value = be16_to_cpup(&buf->data);
                                 ^~~~~~~~~
   13 warnings generated.


vim +705 drivers/input/touchscreen/ads7846.c

   700	
   701	static int ads7846_get_value(struct ads7846_buf *buf)
   702	{
   703		int value;
   704	
 > 705		value = be16_to_cpup(&buf->data);
   706	
   707		/* enforce ADC output is 12 bits width */
   708		return (value >> 3) & 0xfff;
   709	}
   710	

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

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