Messages in this thread | | | Date | Tue, 26 Jul 2022 08:17:15 -0700 | From | Nathan Chancellor <> | 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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On Tue, Jul 26, 2022 at 10:07:09AM +0200, Andy Shevchenko wrote: > Seems yet another false positive from Clang.
This warning should not show up because it is disabled in the main Makefile. Unfortunately, a recent change in clang made '-mtune' warn when it is not supported in the backend, which is the case for ARM:
https://github.com/ClangBuiltLinux/linux/issues/1674
As a result, all subsequent cc-option calls fail, which was the root cause of this warning last time, just with MIPS:
https://lore.kernel.org/YenXz+RznXBuJMSR@dev-arch.archlinux-ax161/
Intel folks, could you update your version of clang or add this particular warning to your blocklist? It should be resolved with https://github.com/llvm/llvm-project/commit/1d23f6c5a4f6ebb101c282f8f506588fe4d9e92f.
Cheers, Nathan
> 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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