Re: [PATCH v1 2/3] firmware: coreboot: loader for Linux-owned SMI handler

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

Hi Michal,

kernel test robot noticed the following build errors:

[auto build test ERROR on chrome-platform/for-next]
[also build test ERROR on chrome-platform/for-firmware-next linus/master v6.16-rc1 next-20250612]
[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/Michal-Gorlas/firmware-coreboot-support-for-parsing-SMM-related-informations-from-coreboot-tables/20250612-221612
base:   https://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux.git for-next
patch link:    https://lore.kernel.org/r/6cfb5bae79c153c54da298c396adb8a28b5e785a.1749734094.git.michal.gorlas%409elements.com
patch subject: [PATCH v1 2/3] firmware: coreboot: loader for Linux-owned SMI handler
config: sh-allmodconfig (https://download.01.org/0day-ci/archive/20250613/202506131541.RxswGh7u-lkp@intel.com/config)
compiler: sh4-linux-gcc (GCC) 15.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250613/202506131541.RxswGh7u-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/202506131541.RxswGh7u-lkp@intel.com/

All errors (new ones prefixed by >>):

   drivers/firmware/google/mm_loader.c: In function 'place_handler':
>> drivers/firmware/google/mm_loader.c:105:9: error: implicit declaration of function 'wbinvd' [-Wimplicit-function-declaration]
     105 |         wbinvd();
         |         ^~~~~~


vim +/wbinvd +105 drivers/firmware/google/mm_loader.c

    84	
    85	static u32 __init place_handler(void)
    86	{
    87		/*
    88		 * The handler (aka MM blob) has to be placed in low 4GB of the memory.
    89		 * This is because we can not assume that coreboot will be in long mode
    90		 * while trying to copy the blob to SMRAM. Even if so, (can be checked by
    91		 * reading cb_data->mm_info.requires_long_mode_call), it would make our life
    92		 * way too complicated (e.g. no need for shared page table).
    93		 */
    94		size_t entry32_offset;
    95		size_t entry64_offset;
    96		u16 real_mode_seg;
    97		const u32 *rel;
    98		u32 count;
    99		unsigned long phys_base;
   100	
   101		blob_size = mm_payload_size_needed();
   102		shared_buffer = (void *)__get_free_pages(GFP_DMA32, get_order(blob_size));
   103	
   104		memcpy(shared_buffer, mm_blob, blob_size);
 > 105		wbinvd();
   106	
   107		/*
   108		 * Based on arch/x86/realmode/init.c
   109		 * The sole purpose of doing relocations is to be able to calculate the offsets
   110		 * for entry points. While the absolute addresses are not valid anymore after the
   111		 * blob is copied to SMRAM, the distances between sections stay the same, so we
   112		 * can still calculate the correct entry point based on coreboot's bitness.
   113		 */
   114		phys_base = __pa(shared_buffer);
   115		real_mode_seg = phys_base >> 4;
   116		rel = (u32 *)mm_relocs;
   117	
   118		/* 16-bit segment relocations. */
   119		count = *rel++;
   120		while (count--) {
   121			u16 *seg = (u16 *)(shared_buffer + *rel++);
   122			*seg = real_mode_seg;
   123		}
   124	
   125		/* 32-bit linear relocations. */
   126		count = *rel++;
   127		while (count--) {
   128			u32 *ptr = (u32 *)(shared_buffer + *rel++);
   129			*ptr += phys_base;
   130		}
   131	
   132		mm_header =  (struct mm_header *)shared_buffer;
   133	
   134		mm_header->mm_signature = REALMODE_END_SIGNATURE;
   135		mm_header->mm_blob_size = mm_payload_size_needed();
   136	
   137		/* At this point relocations are done and we can do some cool
   138		 * pointer arithmetics to help coreboot determine correct entry
   139		 * point based on offsets.
   140		 */
   141		entry32_offset = mm_header->mm_entry_32 - (unsigned long)shared_buffer;
   142		entry64_offset = mm_header->mm_entry_64 - (unsigned long)shared_buffer;
   143	
   144		mm_header->mm_entry_32 = entry32_offset;
   145		mm_header->mm_entry_64 = entry64_offset;
   146	
   147		return (unsigned long)shared_buffer;
   148	}
   149	

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