Re: [PATCH v5 3/5] arm64: libstub: Move KASLR handling functions to kaslr.c

[kernel test robot]

Hi Alexandre,

kernel test robot noticed the following build warnings:

[auto build test WARNING on linus/master]
[also build test WARNING on v6.5-rc2 next-20230721]
[cannot apply to efi/next]
[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-Introduce-virtual-kernel-mapping-KASLR/20230721-155554
base:   linus/master
patch link:    https://lore.kernel.org/r/20230721074850.310644-4-alexghiti%40rivosinc.com
patch subject: [PATCH v5 3/5] arm64: libstub: Move KASLR handling functions to kaslr.c
config: i386-randconfig-i002-20230721 (https://download.01.org/0day-ci/archive/20230722/202307220545.aNYBwGqt-lkp@xxxxxxxxx/config)
compiler: clang version 15.0.7 (https://github.com/llvm/llvm-project.git 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a)
reproduce: (https://download.01.org/0day-ci/archive/20230722/202307220545.aNYBwGqt-lkp@xxxxxxxxx/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202307220545.aNYBwGqt-lkp@xxxxxxxxx/

All warnings (new ones prefixed by >>):

>> drivers/firmware/efi/libstub/kaslr.c:113:23: warning: call to undeclared function 'efi_get_kimg_min_align'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
           u64 min_kimg_align = efi_get_kimg_min_align();
                                ^
>> drivers/firmware/efi/libstub/kaslr.c:155:2: warning: call to undeclared function 'efi_icache_sync'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
           efi_icache_sync(*image_addr, *image_addr + kernel_codesize);
           ^
   2 warnings generated.


vim +/efi_get_kimg_min_align +113 drivers/firmware/efi/libstub/kaslr.c

    87	
    88	/**
    89	 * efi_kaslr_relocate_kernel() - Relocate the kernel (random if KASLR enabled)
    90	 * @image_addr: Pointer to the current kernel location
    91	 * @reserve_addr:	Pointer to the relocated kernel location
    92	 * @reserve_size:	Size of the relocated kernel
    93	 * @kernel_size:	Size of the text + data
    94	 * @kernel_codesize:	Size of the text
    95	 * @kernel_memsize:	Size of the text + data + bss
    96	 * @phys_seed:		Random seed used for the relocation
    97	 *
    98	 * If KASLR is not enabled, this function relocates the kernel to a fixed
    99	 * address (or leave it as its current location). If KASLR is enabled, the
   100	 * kernel physical location is randomized using the seed in parameter.
   101	 *
   102	 * Return:	status code, EFI_SUCCESS if relocation is successful
   103	 */
   104	efi_status_t efi_kaslr_relocate_kernel(unsigned long *image_addr,
   105					       unsigned long *reserve_addr,
   106					       unsigned long *reserve_size,
   107					       unsigned long kernel_size,
   108					       unsigned long kernel_codesize,
   109					       unsigned long kernel_memsize,
   110					       u32 phys_seed)
   111	{
   112		efi_status_t status;
 > 113		u64 min_kimg_align = efi_get_kimg_min_align();
   114	
   115		if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && phys_seed != 0) {
   116			/*
   117			 * If KASLR is enabled, and we have some randomness available,
   118			 * locate the kernel at a randomized offset in physical memory.
   119			 */
   120			status = efi_random_alloc(*reserve_size, min_kimg_align,
   121						  reserve_addr, phys_seed,
   122						  EFI_LOADER_CODE);
   123			if (status != EFI_SUCCESS)
   124				efi_warn("efi_random_alloc() failed: 0x%lx\n", status);
   125		} else {
   126			status = EFI_OUT_OF_RESOURCES;
   127		}
   128	
   129		if (status != EFI_SUCCESS) {
   130			if (!check_image_region(*image_addr, kernel_memsize)) {
   131				efi_err("FIRMWARE BUG: Image BSS overlaps adjacent EFI memory region\n");
   132			} else if (IS_ALIGNED(*image_addr, min_kimg_align) &&
   133				   (u64)_end < EFI_ALLOC_LIMIT) {
   134				/*
   135				 * Just execute from wherever we were loaded by the
   136				 * UEFI PE/COFF loader if the placement is suitable.
   137				 */
   138				*reserve_size = 0;
   139				return EFI_SUCCESS;
   140			}
   141	
   142			status = efi_allocate_pages_aligned(*reserve_size, reserve_addr,
   143							    ULONG_MAX, min_kimg_align,
   144							    EFI_LOADER_CODE);
   145	
   146			if (status != EFI_SUCCESS) {
   147				efi_err("Failed to relocate kernel\n");
   148				*reserve_size = 0;
   149				return status;
   150			}
   151		}
   152	
   153		memcpy((void *)*reserve_addr, (void *)*image_addr, kernel_size);
   154		*image_addr = *reserve_addr;
 > 155		efi_icache_sync(*image_addr, *image_addr + kernel_codesize);

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