// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2013 Linaro Ltd; */ #include #include #include "efistub.h" efi_status_t check_platform_features(void) { int block; /* non-LPAE kernels can run anywhere */ if (!IS_ENABLED(CONFIG_ARM_LPAE)) return EFI_SUCCESS; /* LPAE kernels need compatible hardware */ block = cpuid_feature_extract(CPUID_EXT_MMFR0, 0); if (block < 5) { pr_efi_err("This LPAE kernel is not supported by your CPU\n"); return EFI_UNSUPPORTED; } return EFI_SUCCESS; } static efi_guid_t screen_info_guid = LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID; struct screen_info *alloc_screen_info(void) { struct screen_info *si; efi_status_t status; /* * Unlike on arm64, where we can directly fill out the screen_info * structure from the stub, we need to allocate a buffer to hold * its contents while we hand over to the kernel proper from the * decompressor. */ status = efi_bs_call(allocate_pool, EFI_RUNTIME_SERVICES_DATA, sizeof(*si), (void **)&si); if (status != EFI_SUCCESS) return NULL; status = efi_bs_call(install_configuration_table, &screen_info_guid, si); if (status == EFI_SUCCESS) return si; efi_bs_call(free_pool, si); return NULL; } void free_screen_info(struct screen_info *si) { if (!si) return; efi_bs_call(install_configuration_table, &screen_info_guid, NULL); efi_bs_call(free_pool, si); } static efi_status_t reserve_kernel_base(unsigned long dram_base, unsigned long *reserve_addr, unsigned long *reserve_size) { efi_physical_addr_t alloc_addr; efi_memory_desc_t *memory_map; unsigned long nr_pages, map_size, desc_size, buff_size; efi_status_t status; unsigned long l; struct efi_boot_memmap map = { .map = &memory_map, .map_size = &map_size, .desc_size = &desc_size, .desc_ver = NULL, .key_ptr = NULL, .buff_size = &buff_size, }; /* * Reserve memory for the uncompressed kernel image. This is * all that prevents any future allocations from conflicting * with the kernel. Since we can't tell from the compressed * image how much DRAM the kernel actually uses (due to BSS * size uncertainty) we allocate the maximum possible size. * Do this very early, as prints can cause memory allocations * that may conflict with this. */ alloc_addr = dram_base + MAX_UNCOMP_KERNEL_SIZE; nr_pages = MAX_UNCOMP_KERNEL_SIZE / EFI_PAGE_SIZE; status = efi_bs_call(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS, EFI_BOOT_SERVICES_DATA, nr_pages, &alloc_addr); if (status == EFI_SUCCESS) { if (alloc_addr == dram_base) { *reserve_addr = alloc_addr; *reserve_size = MAX_UNCOMP_KERNEL_SIZE; return EFI_SUCCESS; } /* * If we end up here, the allocation succeeded but starts below * dram_base. This can only occur if the real base of DRAM is * not a multiple of 128 MB, in which case dram_base will have * been rounded up. Since this implies that a part of the region * was already occupied, we need to fall through to the code * below to ensure that the existing allocations don't conflict. * For this reason, we use EFI_BOOT_SERVICES_DATA above and not * EFI_LOADER_DATA, which we wouldn't able to distinguish from * allocations that we want to disallow. */ } /* * If the allocation above failed, we may still be able to proceed: * if the only allocations in the region are of types that will be * released to the OS after ExitBootServices(), the decompressor can * safely overwrite them. */ status = efi_get_memory_map(&map); if (status != EFI_SUCCESS) { pr_efi_err("reserve_kernel_base(): Unable to retrieve memory map.\n"); return status; } for (l = 0; l < map_size; l += desc_size) { efi_memory_desc_t *desc; u64 start, end; desc = (void *)memory_map + l; start = desc->phys_addr; end = start + desc->num_pages * EFI_PAGE_SIZE; /* Skip if entry does not intersect with region */ if (start >= dram_base + MAX_UNCOMP_KERNEL_SIZE || end <= dram_base) continue; switch (desc->type) { case EFI_BOOT_SERVICES_CODE: case EFI_BOOT_SERVICES_DATA: /* Ignore types that are released to the OS anyway */ continue; case EFI_CONVENTIONAL_MEMORY: /* Skip soft reserved conventional memory */ if (efi_soft_reserve_enabled() && (desc->attribute & EFI_MEMORY_SP)) continue; /* * Reserve the intersection between this entry and the * region. */ start = max(start, (u64)dram_base); end = min(end, (u64)dram_base + MAX_UNCOMP_KERNEL_SIZE); status = efi_bs_call(allocate_pages, EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA, (end - start) / EFI_PAGE_SIZE, &start); if (status != EFI_SUCCESS) { pr_efi_err("reserve_kernel_base(): alloc failed.\n"); goto out; } break; case EFI_LOADER_CODE: case EFI_LOADER_DATA: /* * These regions may be released and reallocated for * another purpose (including EFI_RUNTIME_SERVICE_DATA) * at any time during the execution of the OS loader, * so we cannot consider them as safe. */ default: /* * Treat any other allocation in the region as unsafe */ status = EFI_OUT_OF_RESOURCES; goto out; } } status = EFI_SUCCESS; out: efi_bs_call(free_pool, memory_map); return status; } efi_status_t handle_kernel_image(unsigned long *image_addr, unsigned long *image_size, unsigned long *reserve_addr, unsigned long *reserve_size, unsigned long dram_base, efi_loaded_image_t *image) { unsigned long kernel_base; efi_status_t status; /* use a 16 MiB aligned base for the decompressed kernel */ kernel_base = round_up(dram_base, SZ_16M) + TEXT_OFFSET; /* * Note that some platforms (notably, the Raspberry Pi 2) put * spin-tables and other pieces of firmware at the base of RAM, * abusing the fact that the window of TEXT_OFFSET bytes at the * base of the kernel image is only partially used at the moment. * (Up to 5 pages are used for the swapper page tables) */ status = reserve_kernel_base(kernel_base - 5 * PAGE_SIZE, reserve_addr, reserve_size); if (status != EFI_SUCCESS) { pr_efi_err("Unable to allocate memory for uncompressed kernel.\n"); return status; } *image_addr = kernel_base; *image_size = 0; return EFI_SUCCESS; }