Re: arch/mips/include/asm/timex.h:75:10: error: instruction requires a CPU feature not currently enabled

[Jiaxun Yang <jiaxun.yang@flygoat.com>]

> 2023年4月20日 00:18，Nathan Chancellor <nathan@kernel.org> 写道：
> 
> + Jiaxun, who has been looking into MIPS + LLVM issues recently and has
> been a big help :)

I think this patch[1] may fix the problem.

Thanks
- Jiaxun

[1]: https://patchwork.kernel.org/project/linux-mips/patch/20230411111225.55725-2-jiaxun.yang@flygoat.com/

> 
> On Thu, Apr 20, 2023 at 12:37:07AM +0200, Borislav Petkov wrote:
>> + Thomas.
>> 
>> On Mon, Apr 17, 2023 at 07:57:04AM +0800, kernel test robot wrote:
>>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>>> head:   6a8f57ae2eb07ab39a6f0ccad60c760743051026
>>> commit: aba5b397cad7d398b385aaf5029f99f41b690466 hamradio: baycom_epp: Do not use x86-specific rdtsc()
>>> date:   4 months ago
>>> config: mips-buildonly-randconfig-r001-20230417 (https://download.01.org/0day-ci/archive/20230417/202304170748.Fg9VIgGd-lkp@intel.com/config)
>>> compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project 9638da200e00bd069e6dd63604e14cbafede9324)
>> 
>> Where do I get clang 17?
> 
> I think they intend for you to get it via their make.cross script but
> this issue reproduces with clang 16.0.2 from
> https://mirrors.edge.kernel.org/pub/tools/llvm/ for me locally.
> 
>> In any case, this
>> 
>> "error: instruction requires a CPU feature not currently enabled"
>> 
>> sounds like clang is trying to generate invalid code for the wrong
>> target. .config issue?
> 
> I am far from a MIPS expert but this usually means that there is some
> assembler directive that we are missing to allow access to certain
> instructions in newer ISA versions than the one specified via '-march'.
> I have no idea if that is the case here or not but I do see the correct
> target flags when building with V=1, so it is not something obvious like
> that. I can double back to this later this week or next week if nobody
> else is able to.
> 
> Regardless, this seems like a pre-existing issue that was just exposed
> by your patch, not the root cause of it.
> 
> Cheers,
> Nathan
> 
>>> 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-mipsel-linux-gnu
>>>        # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=aba5b397cad7d398b385aaf5029f99f41b690466
>>>        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>>>        git fetch --no-tags linus master
>>>        git checkout aba5b397cad7d398b385aaf5029f99f41b690466
>>>        # save the config file
>>>        mkdir build_dir && cp config build_dir/.config
>>>        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=mips olddefconfig
>>>        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=mips SHELL=/bin/bash drivers/net/hamradio/
>>> 
>>> If you fix the issue, kindly add following tag where applicable
>>> | Reported-by: kernel test robot <lkp@intel.com>
>>> | Link: https://lore.kernel.org/oe-kbuild-all/202304170748.Fg9VIgGd-lkp@intel.com/
>>> 
>>> All errors (new ones prefixed by >>):
>>> 
>>>   In file included from drivers/net/hamradio/baycom_epp.c:29:
>>>   In file included from include/linux/module.h:13:
>>>   In file included from include/linux/stat.h:19:
>>>   In file included from include/linux/time.h:60:
>>>   In file included from include/linux/time32.h:13:
>>>   In file included from include/linux/timex.h:67:
>>>>> arch/mips/include/asm/timex.h:75:10: error: instruction requires a CPU feature not currently enabled
>>>                   return read_c0_count();
>>>                          ^
>>>   arch/mips/include/asm/mipsregs.h:1712:26: note: expanded from macro 'read_c0_count'
>>>   #define read_c0_count()         __read_32bit_c0_register($9, 0)
>>>                                   ^
>>>   arch/mips/include/asm/mipsregs.h:1453:2: note: expanded from macro '__read_32bit_c0_register'
>>>           ___read_32bit_c0_register(source, sel, __volatile__)
>>>           ^
>>>   arch/mips/include/asm/mipsregs.h:1419:4: note: expanded from macro '___read_32bit_c0_register'
>>>                           "mfc0\t%0, " #source "\n\t"                     \
>>>                           ^
>>>   <inline asm>:1:2: note: instantiated into assembly here
>>>           mfc0    $4, $9
>>>           ^
>>>   In file included from drivers/net/hamradio/baycom_epp.c:29:
>>>   In file included from include/linux/module.h:13:
>>>   In file included from include/linux/stat.h:19:
>>>   In file included from include/linux/time.h:60:
>>>   In file included from include/linux/time32.h:13:
>>>   In file included from include/linux/timex.h:67:
>>>>> arch/mips/include/asm/timex.h:75:10: error: instruction requires a CPU feature not currently enabled
>>>                   return read_c0_count();
>>>                          ^
>>>   arch/mips/include/asm/mipsregs.h:1712:26: note: expanded from macro 'read_c0_count'
>>>   #define read_c0_count()         __read_32bit_c0_register($9, 0)
>>>                                   ^
>>>   arch/mips/include/asm/mipsregs.h:1453:2: note: expanded from macro '__read_32bit_c0_register'
>>>           ___read_32bit_c0_register(source, sel, __volatile__)
>>>           ^
>>>   arch/mips/include/asm/mipsregs.h:1419:4: note: expanded from macro '___read_32bit_c0_register'
>>>                           "mfc0\t%0, " #source "\n\t"                     \
>>>                           ^
>>>   <inline asm>:1:2: note: instantiated into assembly here
>>>           mfc0    $2, $9
>>>           ^
>>>   In file included from drivers/net/hamradio/baycom_epp.c:29:
>>>   In file included from include/linux/module.h:13:
>>>   In file included from include/linux/stat.h:19:
>>>   In file included from include/linux/time.h:60:
>>>   In file included from include/linux/time32.h:13:
>>>   In file included from include/linux/timex.h:67:
>>>>> arch/mips/include/asm/timex.h:75:10: error: instruction requires a CPU feature not currently enabled
>>>                   return read_c0_count();
>>>                          ^
>>>   arch/mips/include/asm/mipsregs.h:1712:26: note: expanded from macro 'read_c0_count'
>>>   #define read_c0_count()         __read_32bit_c0_register($9, 0)
>>>                                   ^
>>>   arch/mips/include/asm/mipsregs.h:1453:2: note: expanded from macro '__read_32bit_c0_register'
>>>           ___read_32bit_c0_register(source, sel, __volatile__)
>>>           ^
>>>   arch/mips/include/asm/mipsregs.h:1419:4: note: expanded from macro '___read_32bit_c0_register'
>>>                           "mfc0\t%0, " #source "\n\t"                     \
>>>                           ^
>>>   <inline asm>:1:2: note: instantiated into assembly here
>>>           mfc0    $2, $9
>>>           ^
>>>   In file included from drivers/net/hamradio/baycom_epp.c:29:
>>>   In file included from include/linux/module.h:13:
>>>   In file included from include/linux/stat.h:19:
>>>   In file included from include/linux/time.h:60:
>>>   In file included from include/linux/time32.h:13:
>>>   In file included from include/linux/timex.h:67:
>>>>> arch/mips/include/asm/timex.h:75:10: error: instruction requires a CPU feature not currently enabled
>>>                   return read_c0_count();
>>>                          ^
>>>   arch/mips/include/asm/mipsregs.h:1712:26: note: expanded from macro 'read_c0_count'
>>>   #define read_c0_count()         __read_32bit_c0_register($9, 0)
>>>                                   ^
>>>   arch/mips/include/asm/mipsregs.h:1453:2: note: expanded from macro '__read_32bit_c0_register'
>>>           ___read_32bit_c0_register(source, sel, __volatile__)
>>>           ^
>>>   arch/mips/include/asm/mipsregs.h:1419:4: note: expanded from macro '___read_32bit_c0_register'
>>>                           "mfc0\t%0, " #source "\n\t"                     \
>>>                           ^
>>>   <inline asm>:1:2: note: instantiated into assembly here
>>>           mfc0    $2, $9
>>>           ^
>>>   4 errors generated.
>>> 
>>> 
>>> vim +75 arch/mips/include/asm/timex.h
>>> 
>>> 9c9b415c50bc29 Ralf Baechle       2013-09-12  71  
>>> 06947aaaf9bf7d Maciej W. Rozycki  2014-04-06  72  static inline cycles_t get_cycles(void)
>>> 06947aaaf9bf7d Maciej W. Rozycki  2014-04-06  73  {
>>> 06947aaaf9bf7d Maciej W. Rozycki  2014-04-06  74   if (can_use_mips_counter(read_c0_prid()))
>>> 9c9b415c50bc29 Ralf Baechle       2013-09-12 @75   return read_c0_count();
>>> 06947aaaf9bf7d Maciej W. Rozycki  2014-04-06  76   else
>>> 06947aaaf9bf7d Maciej W. Rozycki  2014-04-06  77   return 0; /* no usable counter */
>>> 9c9b415c50bc29 Ralf Baechle       2013-09-12  78  }
>>> 1c99c6a7c3c599 Jason A. Donenfeld 2022-04-08  79  #define get_cycles get_cycles
>>> 9c9b415c50bc29 Ralf Baechle       2013-09-12  80  
>>> 
>>> :::::: The code at line 75 was first introduced by commit
>>> :::::: 9c9b415c50bc298ac61412dff856eae2f54889ee MIPS: Reimplement get_cycles().
>>> 
>>> :::::: TO: Ralf Baechle <ralf@linux-mips.org>
>>> :::::: CC: Ralf Baechle <ralf@linux-mips.org>
>>> 
>>> -- 
>>> 0-DAY CI Kernel Test Service
>>> https://github.com/intel/lkp-tests
>> 
>> -- 
>> Regards/Gruss,
>>    Boris.
>> 
>> https://people.kernel.org/tglx/notes-about-netiquette