Hi Nicholas,

I love your patch! Yet something to improve:

[auto build test ERROR on powerpc/next]
[also build test ERROR on arm64/for-next/core v5.11-rc6]
[cannot apply to hnaz-linux-mm/master next-20210125]
[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/Nicholas-Piggin/huge-vmalloc-mappings/20210202-190833
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc-mpc834x_mds_defconfig (attached as .config)
compiler: powerpc-linux-gcc (GCC) 9.3.0
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://github.com/0day-ci/linux/commit/ba7c3aca8bdba641f1cc3cd3da5c19da2b5f721a
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Nicholas-Piggin/huge-vmalloc-mappings/20210202-190833
        git checkout ba7c3aca8bdba641f1cc3cd3da5c19da2b5f721a
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=powerpc 

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

All errors (new ones prefixed by >>):

   In file included from arch/powerpc/include/asm/book3s/pgtable.h:8,
                    from arch/powerpc/include/asm/pgtable.h:18,
                    from include/linux/pgtable.h:6,
                    from arch/powerpc/include/asm/kup.h:50,
                    from arch/powerpc/include/asm/uaccess.h:9,
                    from include/linux/uaccess.h:11,
                    from arch/powerpc/kernel/module.c:13:
   arch/powerpc/kernel/module.c: In function 'module_alloc':

quoted

arch/powerpc/include/asm/book3s/32/pgtable.h:189:32: error: 'high_memory' undeclared (first use in this function)

     189 | #define VMALLOC_START ((((long)high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1)))
         |                                ^~~~~~~~~~~
   arch/powerpc/kernel/module.c:92:24: note: in expansion of macro 'VMALLOC_START'
      92 |  unsigned long start = VMALLOC_START;
         |                        ^~~~~~~~~~~~~
   arch/powerpc/include/asm/book3s/32/pgtable.h:189:32: note: each undeclared identifier is reported only once for each function it appears in
     189 | #define VMALLOC_START ((((long)high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1)))
         |                                ^~~~~~~~~~~
   arch/powerpc/kernel/module.c:92:24: note: in expansion of macro 'VMALLOC_START'
      92 |  unsigned long start = VMALLOC_START;
         |                        ^~~~~~~~~~~~~


vim +/high_memory +189 arch/powerpc/include/asm/book3s/32/pgtable.h

63b2bc619565ef Christophe Leroy 2019-02-21  188  
3dfcb315d81e66 Aneesh Kumar K.V 2015-12-01 @189  #define VMALLOC_START ((((long)high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1)))
3d4247fcc938d0 Christophe Leroy 2020-01-14  190  

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