/* * EFI stub implementation that is shared by arm and arm64 architectures. * This should be #included by the EFI stub implementation files. * * Copyright (C) 2013,2014 Linaro Limited * Roy Franz * * This file is part of the Linux kernel, and is made available under the * terms of the GNU General Public License version 2. * */ #include #include #include #include "efistub.h" /* * This is the base address at which to start allocating virtual memory ranges * for UEFI Runtime Services. This is in the low TTBR0 range so that we can use * any allocation we choose, and eliminate the risk of a conflict after kexec. * The value chosen is the largest non-zero power of 2 suitable for this purpose * both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can * be mapped efficiently. * Since 32-bit ARM could potentially execute with a 1G/3G user/kernel split, * map everything below 1 GB. (512 MB is a reasonable upper bound for the * entire footprint of the UEFI runtime services memory regions) */ #define EFI_RT_VIRTUAL_BASE SZ_512M #define EFI_RT_VIRTUAL_SIZE SZ_512M #ifdef CONFIG_ARM64 # define EFI_RT_VIRTUAL_LIMIT TASK_SIZE_64 #else # define EFI_RT_VIRTUAL_LIMIT TASK_SIZE #endif static u64 virtmap_base = EFI_RT_VIRTUAL_BASE; void efi_char16_printk(efi_system_table_t *sys_table_arg, efi_char16_t *str) { struct efi_simple_text_output_protocol *out; out = (struct efi_simple_text_output_protocol *)sys_table_arg->con_out; out->output_string(out, str); } static struct screen_info *setup_graphics(efi_system_table_t *sys_table_arg) { efi_guid_t gop_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID; efi_status_t status; unsigned long size; void **gop_handle = NULL; struct screen_info *si = NULL; size = 0; status = efi_call_early(locate_handle, EFI_LOCATE_BY_PROTOCOL, &gop_proto, NULL, &size, gop_handle); if (status == EFI_BUFFER_TOO_SMALL) { si = alloc_screen_info(sys_table_arg); if (!si) return NULL; efi_setup_gop(sys_table_arg, si, &gop_proto, size); } return si; } /* * This function handles the architcture specific differences between arm and * arm64 regarding where the kernel image must be loaded and any memory that * must be reserved. On failure it is required to free all * all allocations it has made. */ efi_status_t handle_kernel_image(efi_system_table_t *sys_table, 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); /* * EFI entry point for the arm/arm64 EFI stubs. This is the entrypoint * that is described in the PE/COFF header. Most of the code is the same * for both archictectures, with the arch-specific code provided in the * handle_kernel_image() function. */ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, unsigned long *image_addr) { efi_loaded_image_t *image; efi_status_t status; unsigned long image_size = 0; unsigned long dram_base; /* addr/point and size pairs for memory management*/ unsigned long initrd_addr; u64 initrd_size = 0; unsigned long fdt_addr = 0; /* Original DTB */ unsigned long fdt_size = 0; char *cmdline_ptr = NULL; int cmdline_size = 0; unsigned long new_fdt_addr; efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID; unsigned long reserve_addr = 0; unsigned long reserve_size = 0; enum efi_secureboot_mode secure_boot; struct screen_info *si; /* Check if we were booted by the EFI firmware */ if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) goto fail; status = check_platform_features(sys_table); if (status != EFI_SUCCESS) goto fail; /* * Get a handle to the loaded image protocol. This is used to get * information about the running image, such as size and the command * line. */ status = sys_table->boottime->handle_protocol(handle, &loaded_image_proto, (void *)&image); if (status != EFI_SUCCESS) { pr_efi_err(sys_table, "Failed to get loaded image protocol\n"); goto fail; } dram_base = get_dram_base(sys_table); if (dram_base == EFI_ERROR) { pr_efi_err(sys_table, "Failed to find DRAM base\n"); goto fail; } /* * Get the command line from EFI, using the LOADED_IMAGE * protocol. We are going to copy the command line into the * device tree, so this can be allocated anywhere. */ cmdline_ptr = efi_convert_cmdline(sys_table, image, &cmdline_size); if (!cmdline_ptr) { pr_efi_err(sys_table, "getting command line via LOADED_IMAGE_PROTOCOL\n"); goto fail; } if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) || IS_ENABLED(CONFIG_CMDLINE_FORCE) || cmdline_size == 0) efi_parse_options(CONFIG_CMDLINE); if (!IS_ENABLED(CONFIG_CMDLINE_FORCE) && cmdline_size > 0) efi_parse_options(cmdline_ptr); pr_efi(sys_table, "Booting Linux Kernel...\n"); si = setup_graphics(sys_table); status = handle_kernel_image(sys_table, image_addr, &image_size, &reserve_addr, &reserve_size, dram_base, image); if (status != EFI_SUCCESS) { pr_efi_err(sys_table, "Failed to relocate kernel\n"); goto fail_free_cmdline; } /* Ask the firmware to clear memory on unclean shutdown */ efi_enable_reset_attack_mitigation(sys_table); secure_boot = efi_get_secureboot(sys_table); /* * Unauthenticated device tree data is a security hazard, so ignore * 'dtb=' unless UEFI Secure Boot is disabled. We assume that secure * boot is enabled if we can't determine its state. */ if (!IS_ENABLED(CONFIG_EFI_ARMSTUB_DTB_LOADER) || secure_boot != efi_secureboot_mode_disabled) { if (strstr(cmdline_ptr, "dtb=")) pr_efi(sys_table, "Ignoring DTB from command line.\n"); } else { status = handle_cmdline_files(sys_table, image, cmdline_ptr, "dtb=", ~0UL, &fdt_addr, &fdt_size); if (status != EFI_SUCCESS) { pr_efi_err(sys_table, "Failed to load device tree!\n"); goto fail_free_image; } } if (fdt_addr) { pr_efi(sys_table, "Using DTB from command line\n"); } else { /* Look for a device tree configuration table entry. */ fdt_addr = (uintptr_t)get_fdt(sys_table, &fdt_size); if (fdt_addr) pr_efi(sys_table, "Using DTB from configuration table\n"); } if (!fdt_addr) pr_efi(sys_table, "Generating empty DTB\n"); status = handle_cmdline_files(sys_table, image, cmdline_ptr, "initrd=", efi_get_max_initrd_addr(dram_base, *image_addr), (unsigned long *)&initrd_addr, (unsigned long *)&initrd_size); if (status != EFI_SUCCESS) pr_efi_err(sys_table, "Failed initrd from command line!\n"); efi_random_get_seed(sys_table); /* hibernation expects the runtime regions to stay in the same place */ if (!IS_ENABLED(CONFIG_HIBERNATION) && !nokaslr()) { /* * Randomize the base of the UEFI runtime services region. * Preserve the 2 MB alignment of the region by taking a * shift of 21 bit positions into account when scaling * the headroom value using a 32-bit random value. */ static const u64 headroom = EFI_RT_VIRTUAL_LIMIT - EFI_RT_VIRTUAL_BASE - EFI_RT_VIRTUAL_SIZE; u32 rnd; status = efi_get_random_bytes(sys_table, sizeof(rnd), (u8 *)&rnd); if (status == EFI_SUCCESS) { virtmap_base = EFI_RT_VIRTUAL_BASE + (((headroom >> 21) * rnd) >> (32 - 21)); } } new_fdt_addr = fdt_addr; status = allocate_new_fdt_and_exit_boot(sys_table, handle, &new_fdt_addr, efi_get_max_fdt_addr(dram_base), initrd_addr, initrd_size, cmdline_ptr, fdt_addr, fdt_size); /* * If all went well, we need to return the FDT address to the * calling function so it can be passed to kernel as part of * the kernel boot protocol. */ if (status == EFI_SUCCESS) return new_fdt_addr; pr_efi_err(sys_table, "Failed to update FDT and exit boot services\n"); efi_free(sys_table, initrd_size, initrd_addr); efi_free(sys_table, fdt_size, fdt_addr); fail_free_image: efi_free(sys_table, image_size, *image_addr); efi_free(sys_table, reserve_size, reserve_addr); fail_free_cmdline: free_screen_info(sys_table, si); efi_free(sys_table, cmdline_size, (unsigned long)cmdline_ptr); fail: return EFI_ERROR; } static int cmp_mem_desc(const void *l, const void *r) { const efi_memory_desc_t *left = l, *right = r; return (left->phys_addr > right->phys_addr) ? 1 : -1; } /* * Returns whether region @left ends exactly where region @right starts, * or false if either argument is NULL. */ static bool regions_are_adjacent(efi_memory_desc_t *left, efi_memory_desc_t *right) { u64 left_end; if (left == NULL || right == NULL) return false; left_end = left->phys_addr + left->num_pages * EFI_PAGE_SIZE; return left_end == right->phys_addr; } /* * Returns whether region @left and region @right have compatible memory type * mapping attributes, and are both EFI_MEMORY_RUNTIME regions. */ static bool regions_have_compatible_memory_type_attrs(efi_memory_desc_t *left, efi_memory_desc_t *right) { static const u64 mem_type_mask = EFI_MEMORY_WB | EFI_MEMORY_WT | EFI_MEMORY_WC | EFI_MEMORY_UC | EFI_MEMORY_RUNTIME; return ((left->attribute ^ right->attribute) & mem_type_mask) == 0; } /* * efi_get_virtmap() - create a virtual mapping for the EFI memory map * * This function populates the virt_addr fields of all memory region descriptors * in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors * are also copied to @runtime_map, and their total count is returned in @count. */ void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size, unsigned long desc_size, efi_memory_desc_t *runtime_map, int *count) { u64 efi_virt_base = virtmap_base; efi_memory_desc_t *in, *prev = NULL, *out = runtime_map; int l; /* * To work around potential issues with the Properties Table feature * introduced in UEFI 2.5, which may split PE/COFF executable images * in memory into several RuntimeServicesCode and RuntimeServicesData * regions, we need to preserve the relative offsets between adjacent * EFI_MEMORY_RUNTIME regions with the same memory type attributes. * The easiest way to find adjacent regions is to sort the memory map * before traversing it. */ if (IS_ENABLED(CONFIG_ARM64)) sort(memory_map, map_size / desc_size, desc_size, cmp_mem_desc, NULL); for (l = 0; l < map_size; l += desc_size, prev = in) { u64 paddr, size; in = (void *)memory_map + l; if (!(in->attribute & EFI_MEMORY_RUNTIME)) continue; paddr = in->phys_addr; size = in->num_pages * EFI_PAGE_SIZE; if (novamap()) { in->virt_addr = in->phys_addr; continue; } /* * Make the mapping compatible with 64k pages: this allows * a 4k page size kernel to kexec a 64k page size kernel and * vice versa. */ if ((IS_ENABLED(CONFIG_ARM64) && !regions_are_adjacent(prev, in)) || !regions_have_compatible_memory_type_attrs(prev, in)) { paddr = round_down(in->phys_addr, SZ_64K); size += in->phys_addr - paddr; /* * Avoid wasting memory on PTEs by choosing a virtual * base that is compatible with section mappings if this * region has the appropriate size and physical * alignment. (Sections are 2 MB on 4k granule kernels) */ if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M) efi_virt_base = round_up(efi_virt_base, SZ_2M); else efi_virt_base = round_up(efi_virt_base, SZ_64K); } in->virt_addr = efi_virt_base + in->phys_addr - paddr; efi_virt_base += size; memcpy(out, in, desc_size); out = (void *)out + desc_size; ++*count; } }