Subject: Re: [PATCH 2/2] powerpc/watchpoint: Workaround P10 DD1 issue with VSX-32 byte instructions

From: kernel test robot <[email-masked]>
Date: Tue, 20 Oct 2020 15:53:13 +0800

Hi Ravi,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on powerpc/next]
[also build test WARNING on v5.9 next-20201016]
[cannot apply to mpe/next scottwood/next]
[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/Ravi-Bangoria/powerpc-Introduce-POWER10_DD1-feature/20201020-134813
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc-allmodconfig (attached as .config)
compiler: powerpc64-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/a873a50e35b4c881b6bb53f48ae8ef7bb3e576eb
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Ravi-Bangoria/powerpc-Introduce-POWER10_DD1-feature/20201020-134813
        git checkout a873a50e35b4c881b6bb53f48ae8ef7bb3e576eb
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=powerpc 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email-masked]>

All warnings (new ones prefixed by >>):

   arch/powerpc/kernel/hw_breakpoint.c: In function 'handle_p10dd1_spurious_exception':
>> arch/powerpc/kernel/hw_breakpoint.c:561:16: warning: variable 'hw_start_addr' set but not used [-Wunused-but-set-variable]
     561 |  unsigned long hw_start_addr;
         |                ^~~~~~~~~~~~~

vim +/hw_start_addr +561 arch/powerpc/kernel/hw_breakpoint.c

   556	
   557	static void handle_p10dd1_spurious_exception(struct arch_hw_breakpoint **info,
   558						     int *hit, unsigned long ea)
   559	{
   560		int i;
 > 561		unsigned long hw_start_addr;
   562		unsigned long hw_end_addr;
   563	
   564		/*
   565		 * Handle spurious exception only when any bp_per_reg is set.
   566		 * Otherwise this might be created by xmon and not actually a
   567		 * spurious exception.
   568		 */
   569		for (i = 0; i < nr_wp_slots(); i++) {
   570			if (!info[i])
   571				continue;
   572	
   573			hw_start_addr = ALIGN_DOWN(info[i]->address, HW_BREAKPOINT_SIZE);
   574			hw_end_addr = ALIGN(info[i]->address + info[i]->len, HW_BREAKPOINT_SIZE);
   575	
   576			/*
   577			 * Ending address of DAWR range is less than starting
   578			 * address of op.
   579			 */
   580			if ((hw_end_addr - 1) >= ea)
   581				continue;
   582	
   583			/*
   584			 * Those addresses need to be in the same or in two
   585			 * consecutive 512B blocks;
   586			 */
   587			if (((hw_end_addr - 1) >> 10) != (ea >> 10))
   588				continue;
   589	
   590			/*
   591			 * 'op address + 64B' generates an address that has a
   592			 * carry into bit 52 (crosses 2K boundary).
   593			 */
   594			if ((ea & 0x800) == ((ea + 64) & 0x800))
   595				continue;
   596	
   597			break;
   598		}
   599	
   600		if (i == nr_wp_slots())
   601			return;
   602	
   603		for (i = 0; i < nr_wp_slots(); i++) {
   604			if (info[i]) {
   605				hit[i] = 1;
   606				info[i]->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ;
   607			}
   608		}
   609	}
   610	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email-masked]