diff options
| -rw-r--r-- | drivers/firmware/efi/libstub/arm64-stub.c | 49 |
1 files changed, 48 insertions, 1 deletions
diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c index 7bf0a7acae5e..3698c1ce2940 100644 --- a/drivers/firmware/efi/libstub/arm64-stub.c +++ b/drivers/firmware/efi/libstub/arm64-stub.c @@ -35,6 +35,51 @@ efi_status_t check_platform_features(void) } /* + * Distro versions of GRUB may ignore the BSS allocation entirely (i.e., fail + * to provide space, and fail to zero it). Check for this condition by double + * checking that the first and the last byte of the image are covered by the + * same EFI memory map entry. + */ +static bool check_image_region(u64 base, u64 size) +{ + unsigned long map_size, desc_size, buff_size; + efi_memory_desc_t *memory_map; + struct efi_boot_memmap map; + efi_status_t status; + bool ret = false; + int map_offset; + + map.map = &memory_map; + map.map_size = &map_size; + map.desc_size = &desc_size; + map.desc_ver = NULL; + map.key_ptr = NULL; + map.buff_size = &buff_size; + + status = efi_get_memory_map(&map); + if (status != EFI_SUCCESS) + return false; + + for (map_offset = 0; map_offset < map_size; map_offset += desc_size) { + efi_memory_desc_t *md = (void *)memory_map + map_offset; + u64 end = md->phys_addr + md->num_pages * EFI_PAGE_SIZE; + + /* + * Find the region that covers base, and return whether + * it covers base+size bytes. + */ + if (base >= md->phys_addr && base < end) { + ret = (base + size) <= end; + break; + } + } + + efi_bs_call(free_pool, memory_map); + + return ret; +} + +/* * Although relocatable kernels can fix up the misalignment with respect to * MIN_KIMG_ALIGN, the resulting virtual text addresses are subtly out of * sync with those recorded in the vmlinux when kaslr is disabled but the @@ -92,7 +137,9 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, } if (status != EFI_SUCCESS) { - if (IS_ALIGNED((u64)_text, min_kimg_align())) { + if (!check_image_region((u64)_text, kernel_memsize)) { + efi_err("FIRMWARE BUG: Image BSS overlaps adjacent EFI memory region\n"); + } else if (IS_ALIGNED((u64)_text, min_kimg_align())) { /* * Just execute from wherever we were loaded by the * UEFI PE/COFF loader if the alignment is suitable. |