Hi Andrew,

First bad commit (maybe != root cause):

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   d8079fac168168b25677dc16c00ffaf9fb7df723
commit: 529d1fdf9719c2ca6b35c24e88e0e7dd62a9a172 net: mdio: octeon: Select MDIO_DEVRES
date:   10 months ago
config: xtensa-randconfig-r036-20210725 (attached as .config)
compiler: xtensa-linux-gcc (GCC) 10.3.0
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://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=529d1fdf9719c2ca6b35c24e88e0e7dd62a9a172
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout 529d1fdf9719c2ca6b35c24e88e0e7dd62a9a172
        # save the attached .config to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-10.3.0 make.cross O=build_dir ARCH=xtensa SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   arch/xtensa/boot/boot-elf/bootstrap.S: Assembler messages:
>> arch/xtensa/boot/boot-elf/bootstrap.S:56: Error: invalid register 'atomctl' for 'wsr' instruction
   arch/xtensa/boot/boot-elf/bootstrap.S:66: Warning: value 0x1a0003000 truncated to 0xa0003000


vim +56 arch/xtensa/boot/boot-elf/bootstrap.S

e85e335f8ff615 Max Filippov 2012-12-03  42  
e85e335f8ff615 Max Filippov 2012-12-03  43  	.align  4
e85e335f8ff615 Max Filippov 2012-12-03  44  _SetupMMU:
e85e335f8ff615 Max Filippov 2012-12-03  45  	movi	a0, 0
e85e335f8ff615 Max Filippov 2012-12-03  46  	wsr	a0, windowbase
e85e335f8ff615 Max Filippov 2012-12-03  47  	rsync
e85e335f8ff615 Max Filippov 2012-12-03  48  	movi	a0, 1
e85e335f8ff615 Max Filippov 2012-12-03  49  	wsr	a0, windowstart
e85e335f8ff615 Max Filippov 2012-12-03  50  	rsync
e85e335f8ff615 Max Filippov 2012-12-03  51  	movi	a0, 0x1F
e85e335f8ff615 Max Filippov 2012-12-03  52  	wsr	a0, ps
e85e335f8ff615 Max Filippov 2012-12-03  53  	rsync
e85e335f8ff615 Max Filippov 2012-12-03  54  
e85e335f8ff615 Max Filippov 2012-12-03  55  #ifndef CONFIG_INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
e85e335f8ff615 Max Filippov 2012-12-03 @56  	initialize_mmu

:::::: The code at line 56 was first introduced by commit
:::::: e85e335f8ff615f74e29e09cc2599f095600114b xtensa: add MMU v3 support

:::::: TO: Max Filippov <jcmvbkbc@gmail.com>
:::::: CC: Chris Zankel <chris@zankel.net>

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