[PATCH v3 2/6] riscv: Rework kasan population functions

[kernel test robot]

Hi Alexandre,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v6.2-rc6 next-20230131]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Alexandre-Ghiti/riscv-Split-early-and-final-KASAN-population-functions/20230125-163113
patch link:    https://lore.kernel.org/r/20230125082333.1577572-3-alexghiti%40rivosinc.com
patch subject: [PATCH v3 2/6] riscv: Rework kasan population functions
config: riscv-randconfig-r006-20230201 (https://download.01.org/0day-ci/archive/20230201/202302010819.RAsjyv6V-lkp@intel.com/config)
compiler: riscv64-linux-gcc (GCC) 12.1.0
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/c18726e8d14edbd59ec19854b4eb06d83fff716f
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Alexandre-Ghiti/riscv-Split-early-and-final-KASAN-population-functions/20230125-163113
        git checkout c18726e8d14edbd59ec19854b4eb06d83fff716f
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=riscv olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash arch/riscv/mm/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp at intel.com>

All warnings (new ones prefixed by >>):

>> arch/riscv/mm/kasan_init.c:442:6: warning: no previous prototype for 'create_tmp_mapping' [-Wmissing-prototypes]
     442 | void create_tmp_mapping(void)
         |      ^~~~~~~~~~~~~~~~~~


vim +/create_tmp_mapping +442 arch/riscv/mm/kasan_init.c

   441	
 > 442	void create_tmp_mapping(void)
   443	{
   444		void *ptr;
   445		p4d_t *base_p4d;
   446	
   447		/*
   448		 * We need to clean the early mapping: this is hard to achieve "in-place",
   449		 * so install a temporary mapping like arm64 and x86 do.
   450		 */
   451		memcpy(tmp_pg_dir, swapper_pg_dir, sizeof(pgd_t) * PTRS_PER_PGD);
   452	
   453		/* Copy the last p4d since it is shared with the kernel mapping. */
   454		if (pgtable_l5_enabled) {
   455			ptr = (p4d_t *)pgd_page_vaddr(*pgd_offset_k(KASAN_SHADOW_END));
   456			memcpy(tmp_p4d, ptr, sizeof(p4d_t) * PTRS_PER_P4D);
   457			set_pgd(&tmp_pg_dir[pgd_index(KASAN_SHADOW_END)],
   458				pfn_pgd(PFN_DOWN(__pa(tmp_p4d)), PAGE_TABLE));
   459			base_p4d = tmp_p4d;
   460		} else {
   461			base_p4d = (p4d_t *)tmp_pg_dir;
   462		}
   463	
   464		/* Copy the last pud since it is shared with the kernel mapping. */
   465		if (pgtable_l4_enabled) {
   466			ptr = (pud_t *)p4d_page_vaddr(*(base_p4d + p4d_index(KASAN_SHADOW_END)));
   467			memcpy(tmp_pud, ptr, sizeof(pud_t) * PTRS_PER_PUD);
   468			set_p4d(&base_p4d[p4d_index(KASAN_SHADOW_END)],
   469				pfn_p4d(PFN_DOWN(__pa(tmp_pud)), PAGE_TABLE));
   470		}
   471	}
   472	

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