Re: [PATCH] lib/crc: x86: rewrite crc32c_x86_3way() in C with inline asm

[kernel test robot <lkp@intel.com>]

Hi Qu,

kernel test robot noticed the following build errors:

[auto build test ERROR on ebiggers/crc-next]
[also build test ERROR on linus/master v7.4-rc2 next-20261109]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Qu-Wenruo/lib-crc-x86-rewrite-crc32c_x86_3way-in-C-with-inline-asm/20261110-102248
base:   https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux.git crc-next
patch link:    https://lore.kernel.org/r/090c5f6603b1102c877c8649f7a6569f362bfe61.1794268279.git.wqu%40suse.com
patch subject: [PATCH] lib/crc: x86: rewrite crc32c_x86_3way() in C with inline asm
config: x86_64-rhel-9.4 (https://download.01.org/0day-ci/archive/20261110/202611102233.Xe1YmTvH-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20261110/202611102233.Xe1YmTvH-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202611102233.Xe1YmTvH-lkp@intel.com/

All errors (new ones prefixed by >>):

   In function 'crc32c_fold_lanes',
       inlined from 'crc32c_x86_3way' at lib/crc/x86/crc32c-3way.c:285:12:
>> lib/crc/x86/crc32c-3way.c:217:9: error: the register 'xmm2' cannot be clobbered in 'asm' for the current target
     217 |         asm("pmovzxdq   %[k], %%xmm0\n\t"       /* 2 consts: K2:K1 */
         |         ^~~


vim +217 lib/crc/x86/crc32c-3way.c

   208	
   209	/*
   210	 * Fold the CRCs of lane 0 and lane 1 into a single 64-bit value, which is to be
   211	 * XOR'ed into the last qword of lane 2 before being CRC'ed.
   212	 */
   213	static __always_inline u64 crc32c_fold_lanes(u32 crc0, u32 crc1, const u32 *k)
   214	{
   215		u64 res;
   216	
 > 217		asm("pmovzxdq	%[k], %%xmm0\n\t"	/* 2 consts: K2:K1 */
   218		    "movq	%[crc0], %%xmm1\n\t"	/* CRC for lane 0 */
   219		    "pclmulqdq	$0x00, %%xmm0, %%xmm1\n\t" /* Multiply by K2 */
   220		    "movq	%[crc1], %%xmm2\n\t"	/* CRC for lane 1 */
   221		    "pclmulqdq	$0x10, %%xmm0, %%xmm2\n\t" /* Multiply by K1 */
   222		    "pxor	%%xmm2, %%xmm1\n\t"
   223		    "movq	%%xmm1, %[res]"
   224		    : [res] "=r" (res)
   225		    : [crc0] "r" ((u64)crc0), [crc1] "r" ((u64)crc1),
   226		      [k] "m" (*(const u64 *)k)
   227		    : "xmm0", "xmm1", "xmm2");
   228		return res;
   229	}
   230	

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