Hi Suzuki,

I love your patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on next-20210226]
[cannot apply to kvmarm/next arm64/for-next/core tip/perf/core v5.11]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Suzuki-K-Poulose/arm64-coresight-Add-support-for-ETE-and-TRBE/20210226-035447
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 6fbd6cf85a3be127454a1ad58525a3adcf8612ab
config: arm64-allyesconfig (attached as .config)
compiler: aarch64-linux-gcc (GCC) 9.3.0
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
        # https://github.com/0day-ci/linux/commit/66c402c1fecfcacd92971f7c4ef6ee17f8243745
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Suzuki-K-Poulose/arm64-coresight-Add-support-for-ETE-and-TRBE/20210226-035447
        git checkout 66c402c1fecfcacd92971f7c4ef6ee17f8243745
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm64 

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/hwtracing/coresight/coresight-etm4x-core.c:118:5: warning: no previous prototype for 'ete_sysreg_read' [-Wmissing-prototypes]
     118 | u64 ete_sysreg_read(u32 offset, bool _relaxed, bool _64bit)
         |     ^~~~~~~~~~~~~~~
>> drivers/hwtracing/coresight/coresight-etm4x-core.c:135:6: warning: no previous prototype for 'ete_sysreg_write' [-Wmissing-prototypes]
     135 | void ete_sysreg_write(u64 val, u32 offset, bool _relaxed, bool _64bit)
         |      ^~~~~~~~~~~~~~~~


vim +/ete_sysreg_read +118 drivers/hwtracing/coresight/coresight-etm4x-core.c

   117	
 > 118	u64 ete_sysreg_read(u32 offset, bool _relaxed, bool _64bit)
   119	{
   120		u64 res = 0;
   121	
   122		switch (offset) {
   123		ETE_READ_CASES(res)
   124		default :
   125			pr_warn_ratelimited("ete: trying to read unsupported register @%x\n",
   126					    offset);
   127		}
   128	
   129		if (!_relaxed)
   130			__iormb(res);	/* Imitate the !relaxed I/O helpers */
   131	
   132		return res;
   133	}
   134	
 > 135	void ete_sysreg_write(u64 val, u32 offset, bool _relaxed, bool _64bit)
   136	{
   137		if (!_relaxed)
   138			__iowmb();	/* Imitate the !relaxed I/O helpers */
   139		if (!_64bit)
   140			val &= GENMASK(31, 0);
   141	
   142		switch (offset) {
   143		ETE_WRITE_CASES(val)
   144		default :
   145			pr_warn_ratelimited("ete: trying to write to unsupported register @%x\n",
   146					    offset);
   147		}
   148	}
   149	

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