[PATCH v2 resend 2/3] arm64: mm: Don't defer reserve_crashkernel() with dma_force_32bit

[Kefeng Wang]

On 2022/4/1 0:14, kernel test robot wrote:
> Hi Kefeng,
>
> Thank you for the patch! Perhaps something to improve:
>
> [auto build test WARNING on next-20220330]
> [cannot apply to arm64/for-next/core v5.17 v5.17-rc8 v5.17-rc7 v5.17]
> [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/intel-lab-lkp/linux/commits/Kefeng-Wang/arm64-mm-Do-not-defer-reserve_crashkernel/20220331-152839
> base:    a67ba3cf9551f8c92d5ec9d7eae1aadbb9127b57
> config: arm64-buildonly-randconfig-r001-20220331 (https://download.01.org/0day-ci/archive/20220401/202204010040.RUk6NuNS-lkp@intel.com/config)
> compiler: aarch64-linux-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/intel-lab-lkp/linux/commit/970ec526bd69287a4eb9838600aaf66c46fde350
>          git remote add linux-review https://github.com/intel-lab-lkp/linux
>          git fetch --no-tags linux-review Kefeng-Wang/arm64-mm-Do-not-defer-reserve_crashkernel/20220331-152839
>          git checkout 970ec526bd69287a4eb9838600aaf66c46fde350
>          # save the config file to linux build tree
>          mkdir build_dir
>          COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=arm64 SHELL=/bin/bash arch/arm64/mm/
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp at intel.com>
>
> All warnings (new ones prefixed by >>):
>
>>> arch/arm64/mm/init.c:108:13: warning: no previous prototype for 'crashkernel_could_early_reserve' [-Wmissing-prototypes]
>       108 | bool __init crashkernel_could_early_reserve(void)
>           |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Let's wait for some feedback, add <asm/kexec.h> into init.c could 
silence the warning.

thanks.

>
> vim +/crashkernel_could_early_reserve +108 arch/arm64/mm/init.c
>
>     107	
>   > 108	bool __init crashkernel_could_early_reserve(void)
>     109	{
>     110		if (!IS_ENABLED(CONFIG_ZONE_DMA))
>     111			return true;
>     112		if (arm64_dma_force_32bit)
>     113			return true;
>     114		return false;
>     115	}
>     116	
>