From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: kernel test robot <lkp@intel.com>
Cc: llvm@lists.linux.dev, kbuild-all@lists.01.org,
linux-kernel@vger.kernel.org,
Michael Ellerman <mpe@ellerman.id.au>
Subject: Re: [linuxppc:next-test 71/141] drivers/net/ethernet/sfc/falcon/farch.c:994:10: warning: shift count is negative
Date: Wed, 1 Sep 2021 15:20:47 +0200 [thread overview]
Message-ID: <f96f87e8-1a9c-a43c-82ef-787de35deef2@csgroup.eu> (raw)
In-Reply-To: <202109011018.QFMpsm0d-lkp@intel.com>
Le 01/09/2021 à 04:54, kernel test robot a écrit :
> tree: https://github.com/linuxppc/linux next-test
> head: c7dee506ec3450717e84518ab3a6a3f2ce755cf6
> commit: 1e688dd2a3d6759d416616ff07afc4bb836c4213 [71/141] powerpc/bug: Provide better flexibility to WARN_ON/__WARN_FLAGS() with asm goto
> config: powerpc-randconfig-r031-20210901 (attached as .config)
> compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 4b1fde8a2b681dad2ce0c082a5d6422caa06b0bc)
Apparently a clang problem. This doesn't happen with GCC.
> 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 powerpc cross compiling tool for clang build
> # apt-get install binutils-powerpc64-linux-gnu
> # https://github.com/linuxppc/linux/commit/1e688dd2a3d6759d416616ff07afc4bb836c4213
> git remote add linuxppc https://github.com/linuxppc/linux
> git fetch --no-tags linuxppc next-test
> git checkout 1e688dd2a3d6759d416616ff07afc4bb836c4213
> # save the attached .config to linux build tree
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc
>
> 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 >>):
>
>>> drivers/net/ethernet/sfc/falcon/farch.c:994:10: warning: shift count is negative [-Wshift-count-negative]
> WARN_ON(EF4_QWORD_FIELD(*event, FSF_AZ_RX_EV_Q_LABEL) !=
> ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/net/ethernet/sfc/falcon/bitfield.h:222:26: note: expanded from macro 'EF4_QWORD_FIELD'
> #define EF4_QWORD_FIELD EF4_QWORD_FIELD64
> ^
> drivers/net/ethernet/sfc/falcon/bitfield.h:173:2: note: expanded from macro 'EF4_QWORD_FIELD64'
> EF4_EXTRACT_QWORD64(qword, EF4_LOW_BIT(field), \
> ^
> drivers/net/ethernet/sfc/falcon/bitfield.h:149:3: note: expanded from macro 'EF4_EXTRACT_QWORD64'
> (EF4_EXTRACT64((qword).u64[0], 0, 63, low, high) & \
> ^
> note: (skipping 2 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
> arch/powerpc/include/asm/bug.h:122:30: note: expanded from macro 'WARN_ON'
> __label_warn_on, "r" (x)); \
> ~~~~~~~~~~~~~~~~~~~~~~^~~
> arch/powerpc/include/asm/bug.h:75:7: note: expanded from macro 'WARN_ENTRY'
> ##__VA_ARGS__ : : label)
> ~~^~~~~~~~~~~~~~~~~~~~~~
> include/linux/compiler_types.h:254:42: note: expanded from macro 'asm_volatile_goto'
> #define asm_volatile_goto(x...) asm goto(x)
> ^
> 1 warning generated.
Complete with -fmacro-backtrace-limit=0 :
CC drivers/net/ethernet/sfc/falcon/farch.o
drivers/net/ethernet/sfc/falcon/farch.c:994:10: warning: shift count is
negative [-Wshift-count-negative]
WARN_ON(EF4_QWORD_FIELD(*event, FSF_AZ_RX_EV_Q_LABEL) !=
~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/ethernet/sfc/falcon/bitfield.h:222:26: note: expanded from
macro 'EF4_QWORD_FIELD'
#define EF4_QWORD_FIELD EF4_QWORD_FIELD64
^
drivers/net/ethernet/sfc/falcon/bitfield.h:173:2: note: expanded from
macro 'EF4_QWORD_FIELD64'
EF4_EXTRACT_QWORD64(qword, EF4_LOW_BIT(field), \
^
drivers/net/ethernet/sfc/falcon/bitfield.h:149:3: note: expanded from
macro 'EF4_EXTRACT_QWORD64'
(EF4_EXTRACT64((qword).u64[0], 0, 63, low, high) & \
^
drivers/net/ethernet/sfc/falcon/bitfield.h:134:2: note: expanded from
macro 'EF4_EXTRACT64'
EF4_EXTRACT_NATIVE(le64_to_cpu(element), min, max, low, high)
^
drivers/net/ethernet/sfc/falcon/bitfield.h:127:20: note: expanded from
macro 'EF4_EXTRACT_NATIVE'
(native_element) << ((min) - (low)))
^
./arch/powerpc/include/asm/bug.h:122:30: note: expanded from macro 'WARN_ON'
__label_warn_on, "r" (x)); \
~~~~~~~~~~~~~~~~~~~~~~^~~
./arch/powerpc/include/asm/bug.h:75:7: note: expanded from macro
'WARN_ENTRY'
##__VA_ARGS__ : : label)
~~^~~~~~~~~~~~~~~~~~~~~~
./include/linux/compiler_types.h:254:42: note: expanded from macro
'asm_volatile_goto'
#define asm_volatile_goto(x...) asm goto(x)
^
1 warning generated.
The warning makes no sense because this part of the macro is as follows
so there is no way the shift can be negative.
(low) > (min) ? \
(native_element) >> ((low) - (min)) : \
(native_element) << ((min) - (low)))
Christophe
prev parent reply other threads:[~2021-09-01 13:20 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-01 2:54 [linuxppc:next-test 71/141] drivers/net/ethernet/sfc/falcon/farch.c:994:10: warning: shift count is negative kernel test robot
2021-09-01 13:20 ` Christophe Leroy [this message]
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