[gerg-m68knommu:dt 12/14] arch/m68k/kernel/setup_mm.c:211:35: error: '__dtb_start' undeclared; did you mean '__bss_start'?

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu.git dt
head:   3173490642db7ab3c9f15b139b19a633a2ac2d5e
commit: c9921b3e98eab8277d9aa71cc084cc821fd14213 [12/14] m68k: implement a builtin devicetree for mm targets
config: m68k-randconfig-r051-20260519 (https://download.01.org/0day-ci/archive/20260519/[email protected]/config)
compiler: m68k-linux-gcc (GCC) 8.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260519/[email protected]/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 <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/

All errors (new ones prefixed by >>):

   In file included from arch/m68k/kernel/setup.c:3:
   arch/m68k/kernel/setup_mm.c: In function 'm68k_setup_fdt':
>> arch/m68k/kernel/setup_mm.c:211:35: error: '__dtb_start' undeclared (first use in this function); did you mean '__bss_start'?
     phys_addr_t fdt = (phys_addr_t) &__dtb_start;
                                      ^~~~~~~~~~~
                                      __bss_start
   arch/m68k/kernel/setup_mm.c:211:35: note: each undeclared identifier is reported only once for each function it appears in

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for OF_EARLY_FLATTREE
   Depends on [n]: OF [=n]
   Selected by [y]:
   - BUILTIN_DTB [=y]


vim +211 arch/m68k/kernel/setup_mm.c

   207	
   208	#ifdef CONFIG_BUILTIN_DTB
   209	static void __init m68k_setup_fdt(void)
   210	{
 > 211		phys_addr_t fdt = (phys_addr_t) &__dtb_start;
   212	
   213		pr_info("m68k generic DT machine support, FDT blob at 0x%08x\n", fdt);
   214		if (!early_init_dt_verify(__va(fdt), fdt)) {
   215			pr_err("FDT blob is bad?!\n");
   216			return;
   217		}
   218		early_init_dt_scan_nodes();
   219		unflatten_device_tree();
   220	}
   221