Hi,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on arm/for-next]
[also build test ERROR on xilinx-xlnx/master soc/for-next rockchip/for-next arm64/for-next/core shawnguo/for-next clk/clk-next kvmarm/next linus/master keystone/next v5.15-rc7 next-20211029]
[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/quanyang-wang-windriver-com/ARM-add-BUILD_BUG_ON-to-check-if-fixmap-range-spans-multiple-pmds/20211020-135145
base:   git://git.armlinux.org.uk/~rmk/linux-arm.git for-next
config: arm-defconfig (attached as .config)
compiler: arm-linux-gnueabi-gcc (GCC) 11.2.0
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/54649c5c19414a00a548a13dd596037c5e50a241
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review quanyang-wang-windriver-com/ARM-add-BUILD_BUG_ON-to-check-if-fixmap-range-spans-multiple-pmds/20211020-135145
        git checkout 54649c5c19414a00a548a13dd596037c5e50a241
        # save the attached .config to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=arm SHELL=/bin/bash

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

All errors (new ones prefixed by >>):

   arch/arm/mm/mmu.c:118:13: warning: no previous prototype for 'init_default_cache_policy' [-Wmissing-prototypes]
     118 | void __init init_default_cache_policy(unsigned long pmd)
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~
   arch/arm/mm/mmu.c:1158:13: warning: no previous prototype for 'adjust_lowmem_bounds' [-Wmissing-prototypes]
    1158 | void __init adjust_lowmem_bounds(void)
         |             ^~~~~~~~~~~~~~~~~~~~
   arch/arm/mm/mmu.c:1724:13: warning: no previous prototype for 'paging_init' [-Wmissing-prototypes]
    1724 | void __init paging_init(const struct machine_desc *mdesc)
         |             ^~~~~~~~~~~
   arch/arm/mm/mmu.c:1757:13: warning: no previous prototype for 'early_mm_init' [-Wmissing-prototypes]
    1757 | void __init early_mm_init(const struct machine_desc *mdesc)
         |             ^~~~~~~~~~~~~
   In file included from <command-line>:
   arch/arm/mm/mmu.c: In function 'early_fixmap_init':

quoted

include/linux/compiler_types.h:322:45: error: call to '__compiletime_assert_295' declared with attribute error: BUILD_BUG_ON failed: (__fix_to_virt(__end_of_fixmap_region) >> PMD_SHIFT) != FIXADDR_TOP >> PMD_SHIFT

     322 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
         |                                             ^
   include/linux/compiler_types.h:303:25: note: in definition of macro '__compiletime_assert'
     303 |                         prefix ## suffix();                             \
         |                         ^~~~~~
   include/linux/compiler_types.h:322:9: note: in expansion of macro '_compiletime_assert'
     322 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
         |         ^~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
      39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
         |                                     ^~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:50:9: note: in expansion of macro 'BUILD_BUG_ON_MSG'
      50 |         BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
         |         ^~~~~~~~~~~~~~~~
   arch/arm/mm/mmu.c:372:9: note: in expansion of macro 'BUILD_BUG_ON'
     372 |         BUILD_BUG_ON((__fix_to_virt(__end_of_fixmap_region) >> PMD_SHIFT)
         |         ^~~~~~~~~~~~


vim +/__compiletime_assert_295 +322 include/linux/compiler_types.h

eb5c2d4b45e3d2 Will Deacon 2020-07-21  308  
eb5c2d4b45e3d2 Will Deacon 2020-07-21  309  #define _compiletime_assert(condition, msg, prefix, suffix) \
eb5c2d4b45e3d2 Will Deacon 2020-07-21  310  	__compiletime_assert(condition, msg, prefix, suffix)
eb5c2d4b45e3d2 Will Deacon 2020-07-21  311  
eb5c2d4b45e3d2 Will Deacon 2020-07-21  312  /**
eb5c2d4b45e3d2 Will Deacon 2020-07-21  313   * compiletime_assert - break build and emit msg if condition is false
eb5c2d4b45e3d2 Will Deacon 2020-07-21  314   * @condition: a compile-time constant condition to check
eb5c2d4b45e3d2 Will Deacon 2020-07-21  315   * @msg:       a message to emit if condition is false
eb5c2d4b45e3d2 Will Deacon 2020-07-21  316   *
eb5c2d4b45e3d2 Will Deacon 2020-07-21  317   * In tradition of POSIX assert, this macro will break the build if the
eb5c2d4b45e3d2 Will Deacon 2020-07-21  318   * supplied condition is *false*, emitting the supplied error message if the
eb5c2d4b45e3d2 Will Deacon 2020-07-21  319   * compiler has support to do so.
eb5c2d4b45e3d2 Will Deacon 2020-07-21  320   */
eb5c2d4b45e3d2 Will Deacon 2020-07-21  321  #define compiletime_assert(condition, msg) \
eb5c2d4b45e3d2 Will Deacon 2020-07-21 @322  	_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
eb5c2d4b45e3d2 Will Deacon 2020-07-21  323  

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