| /* |
| * 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 <roy.franz@linaro.org |
| * Copyright (C) 2013 Red Hat, Inc. |
| * Mark Salter <msalter@redhat.com> |
| * |
| * This file is part of the Linux kernel, and is made available under the |
| * terms of the GNU General Public License version 2. |
| * |
| */ |
| |
| #include <linux/efi.h> |
| #include <linux/sort.h> |
| #include <asm/efi.h> |
| |
| #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; |
| |
| /* |
| * 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; |
| } |
| } |