Messages in this thread | | | From | Andy Shevchenko <> | Date | Tue, 26 Jul 2022 10:07:09 +0200 | Subject | Re: drivers/iio/adc/ti-tsc2046.c:242:62: warning: taking address of packed member 'data' of class or structure 'tsc2046_adc_atom' may result in an unaligned pointer value |
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Seems yet another false positive from Clang.
On Mon, Jul 25, 2022 at 5:55 AM kernel test robot <lkp@intel.com> wrote: > > Hi Oleksij, > > FYI, the error/warning still remains. > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master > head: e0dccc3b76fb35bb257b4118367a883073d7390e > commit: 9374e8f5a38defe90bc65b2decf317c1c62d91dd iio: adc: add ADC driver for the TI TSC2046 controller > date: 1 year, 2 months ago > config: arm-randconfig-r025-20220724 (https://download.01.org/0day-ci/archive/20220725/202207251140.M7YAqoLC-lkp@intel.com/config) > compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 9e88cbcc403bdf82f29259ad60ff60a8fc4434a1) > 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 arm cross compiling tool for clang build > # apt-get install binutils-arm-linux-gnueabi > # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9374e8f5a38defe90bc65b2decf317c1c62d91dd > git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > git fetch --no-tags linus master > git checkout 9374e8f5a38defe90bc65b2decf317c1c62d91dd > # save the config file > mkdir build_dir && cp config build_dir/.config > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash drivers/iio/adc/ drivers/staging/ fs/ > > If you fix the issue, kindly add following tag where applicable > Reported-by: kernel test robot <lkp@intel.com> > > All warnings (new ones prefixed by >>): > > >> drivers/iio/adc/ti-tsc2046.c:242:62: warning: taking address of packed member 'data' of class or structure 'tsc2046_adc_atom' may result in an unaligned pointer value [-Waddress-of-packed-member]
What the heck? The get_unaligned_*() is exactly to get unaligned data.
> return FIELD_GET(TI_TSC2046_DATA_12BIT, get_unaligned_be16(&buf->data)); > ^~~~~~~~~ > include/linux/bitfield.h:108:27: note: expanded from macro 'FIELD_GET' > __BF_FIELD_CHECK(_mask, _reg, 0U, "FIELD_GET: "); \ > ^~~~ > include/linux/bitfield.h:52:38: note: expanded from macro '__BF_FIELD_CHECK' > BUILD_BUG_ON_MSG((_mask) > (typeof(_reg))~0ull, \ > ^~~~ > include/linux/build_bug.h:39:58: note: expanded from macro 'BUILD_BUG_ON_MSG' > #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) > ^~~~ > note: (skipping 2 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all) > include/linux/compiler_types.h:308:9: note: expanded from macro '__compiletime_assert' > if (!(condition)) \ > ^~~~~~~~~ > include/linux/compiler.h:56:47: note: expanded from macro 'if' > #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) ) > ^~~~ > include/linux/compiler.h:58:52: note: expanded from macro '__trace_if_var' > #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond)) > ^~~~ > >> drivers/iio/adc/ti-tsc2046.c:242:62: warning: taking address of packed member 'data' of class or structure 'tsc2046_adc_atom' may result in an unaligned pointer value [-Waddress-of-packed-member] > return FIELD_GET(TI_TSC2046_DATA_12BIT, get_unaligned_be16(&buf->data)); > ^~~~~~~~~ > include/linux/bitfield.h:108:27: note: expanded from macro 'FIELD_GET' > __BF_FIELD_CHECK(_mask, _reg, 0U, "FIELD_GET: "); \ > ^~~~ > include/linux/bitfield.h:52:38: note: expanded from macro '__BF_FIELD_CHECK' > BUILD_BUG_ON_MSG((_mask) > (typeof(_reg))~0ull, \ > ^~~~ > include/linux/build_bug.h:39:58: note: expanded from macro 'BUILD_BUG_ON_MSG' > #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) > ^~~~ > note: (skipping 2 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all) > include/linux/compiler_types.h:308:9: note: expanded from macro '__compiletime_assert' > if (!(condition)) \ > ^~~~~~~~~ > include/linux/compiler.h:56:47: note: expanded from macro 'if' > #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) ) > ^~~~ > include/linux/compiler.h:58:61: note: expanded from macro '__trace_if_var' > #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond)) > ^~~~ > >> drivers/iio/adc/ti-tsc2046.c:242:62: warning: taking address of packed member 'data' of class or structure 'tsc2046_adc_atom' may result in an unaligned pointer value [-Waddress-of-packed-member] > return FIELD_GET(TI_TSC2046_DATA_12BIT, get_unaligned_be16(&buf->data)); > ^~~~~~~~~ > include/linux/bitfield.h:108:27: note: expanded from macro 'FIELD_GET' > __BF_FIELD_CHECK(_mask, _reg, 0U, "FIELD_GET: "); \ > ^~~~ > include/linux/bitfield.h:52:38: note: expanded from macro '__BF_FIELD_CHECK' > BUILD_BUG_ON_MSG((_mask) > (typeof(_reg))~0ull, \ > ^~~~ > include/linux/build_bug.h:39:58: note: expanded from macro 'BUILD_BUG_ON_MSG' > #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) > ^~~~ > note: (skipping 3 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all) > include/linux/compiler.h:56:47: note: expanded from macro 'if' > #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) ) > ^~~~ > include/linux/compiler.h:58:86: note: expanded from macro '__trace_if_var' > #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond)) > ^~~~ > include/linux/compiler.h:69:3: note: expanded from macro '__trace_if_value' > (cond) ? \ > ^~~~ > 3 warnings generated. > > > vim +242 drivers/iio/adc/ti-tsc2046.c > > 239 > 240 static u16 tsc2046_adc_get_value(struct tsc2046_adc_atom *buf) > 241 { > > 242 return FIELD_GET(TI_TSC2046_DATA_12BIT, get_unaligned_be16(&buf->data)); > 243 }
-- With Best Regards, Andy Shevchenko
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