2 * EFI stub implementation that is shared by arm and arm64 architectures.
3 * This should be #included by the EFI stub implementation files.
5 * Copyright (C) 2013,2014 Linaro Limited
6 * Roy Franz <roy.franz@linaro.org
7 * Copyright (C) 2013 Red Hat, Inc.
8 * Mark Salter <msalter@redhat.com>
10 * This file is part of the Linux kernel, and is made available under the
11 * terms of the GNU General Public License version 2.
15 #include <linux/efi.h>
16 #include <linux/sort.h>
21 efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
22 void *__image, void **__fh)
24 efi_file_io_interface_t *io;
25 efi_loaded_image_t *image = __image;
26 efi_file_handle_t *fh;
27 efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
29 void *handle = (void *)(unsigned long)image->device_handle;
31 status = sys_table_arg->boottime->handle_protocol(handle,
32 &fs_proto, (void **)&io);
33 if (status != EFI_SUCCESS) {
34 efi_printk(sys_table_arg, "Failed to handle fs_proto\n");
38 status = io->open_volume(io, &fh);
39 if (status != EFI_SUCCESS)
40 efi_printk(sys_table_arg, "Failed to open volume\n");
46 void efi_char16_printk(efi_system_table_t *sys_table_arg,
49 struct efi_simple_text_output_protocol *out;
51 out = (struct efi_simple_text_output_protocol *)sys_table_arg->con_out;
52 out->output_string(out, str);
55 static struct screen_info *setup_graphics(efi_system_table_t *sys_table_arg)
57 efi_guid_t gop_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
60 void **gop_handle = NULL;
61 struct screen_info *si = NULL;
64 status = efi_call_early(locate_handle, EFI_LOCATE_BY_PROTOCOL,
65 &gop_proto, NULL, &size, gop_handle);
66 if (status == EFI_BUFFER_TOO_SMALL) {
67 si = alloc_screen_info(sys_table_arg);
70 efi_setup_gop(sys_table_arg, si, &gop_proto, size);
76 * This function handles the architcture specific differences between arm and
77 * arm64 regarding where the kernel image must be loaded and any memory that
78 * must be reserved. On failure it is required to free all
79 * all allocations it has made.
81 efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
82 unsigned long *image_addr,
83 unsigned long *image_size,
84 unsigned long *reserve_addr,
85 unsigned long *reserve_size,
86 unsigned long dram_base,
87 efi_loaded_image_t *image);
89 * EFI entry point for the arm/arm64 EFI stubs. This is the entrypoint
90 * that is described in the PE/COFF header. Most of the code is the same
91 * for both archictectures, with the arch-specific code provided in the
92 * handle_kernel_image() function.
94 unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
95 unsigned long *image_addr)
97 efi_loaded_image_t *image;
99 unsigned long image_size = 0;
100 unsigned long dram_base;
101 /* addr/point and size pairs for memory management*/
102 unsigned long initrd_addr;
104 unsigned long fdt_addr = 0; /* Original DTB */
105 unsigned long fdt_size = 0;
106 char *cmdline_ptr = NULL;
107 int cmdline_size = 0;
108 unsigned long new_fdt_addr;
109 efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
110 unsigned long reserve_addr = 0;
111 unsigned long reserve_size = 0;
112 enum efi_secureboot_mode secure_boot;
113 struct screen_info *si;
115 /* Check if we were booted by the EFI firmware */
116 if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
119 pr_efi(sys_table, "Booting Linux Kernel...\n");
121 status = check_platform_features(sys_table);
122 if (status != EFI_SUCCESS)
126 * Get a handle to the loaded image protocol. This is used to get
127 * information about the running image, such as size and the command
130 status = sys_table->boottime->handle_protocol(handle,
131 &loaded_image_proto, (void *)&image);
132 if (status != EFI_SUCCESS) {
133 pr_efi_err(sys_table, "Failed to get loaded image protocol\n");
137 dram_base = get_dram_base(sys_table);
138 if (dram_base == EFI_ERROR) {
139 pr_efi_err(sys_table, "Failed to find DRAM base\n");
144 * Get the command line from EFI, using the LOADED_IMAGE
145 * protocol. We are going to copy the command line into the
146 * device tree, so this can be allocated anywhere.
148 cmdline_ptr = efi_convert_cmdline(sys_table, image, &cmdline_size);
150 pr_efi_err(sys_table, "getting command line via LOADED_IMAGE_PROTOCOL\n");
154 si = setup_graphics(sys_table);
156 status = handle_kernel_image(sys_table, image_addr, &image_size,
160 if (status != EFI_SUCCESS) {
161 pr_efi_err(sys_table, "Failed to relocate kernel\n");
162 goto fail_free_cmdline;
165 if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) ||
166 IS_ENABLED(CONFIG_CMDLINE_FORCE) ||
168 efi_parse_options(CONFIG_CMDLINE);
170 if (!IS_ENABLED(CONFIG_CMDLINE_FORCE) && cmdline_size > 0)
171 efi_parse_options(cmdline_ptr);
173 secure_boot = efi_get_secureboot(sys_table);
176 * Unauthenticated device tree data is a security hazard, so ignore
177 * 'dtb=' unless UEFI Secure Boot is disabled. We assume that secure
178 * boot is enabled if we can't determine its state.
180 if (secure_boot != efi_secureboot_mode_disabled &&
181 strstr(cmdline_ptr, "dtb=")) {
182 pr_efi(sys_table, "Ignoring DTB from command line.\n");
184 status = handle_cmdline_files(sys_table, image, cmdline_ptr,
186 ~0UL, &fdt_addr, &fdt_size);
188 if (status != EFI_SUCCESS) {
189 pr_efi_err(sys_table, "Failed to load device tree!\n");
190 goto fail_free_image;
195 pr_efi(sys_table, "Using DTB from command line\n");
197 /* Look for a device tree configuration table entry. */
198 fdt_addr = (uintptr_t)get_fdt(sys_table, &fdt_size);
200 pr_efi(sys_table, "Using DTB from configuration table\n");
204 pr_efi(sys_table, "Generating empty DTB\n");
206 status = handle_cmdline_files(sys_table, image, cmdline_ptr, "initrd=",
207 efi_get_max_initrd_addr(dram_base,
209 (unsigned long *)&initrd_addr,
210 (unsigned long *)&initrd_size);
211 if (status != EFI_SUCCESS)
212 pr_efi_err(sys_table, "Failed initrd from command line!\n");
214 efi_random_get_seed(sys_table);
216 new_fdt_addr = fdt_addr;
217 status = allocate_new_fdt_and_exit_boot(sys_table, handle,
218 &new_fdt_addr, efi_get_max_fdt_addr(dram_base),
219 initrd_addr, initrd_size, cmdline_ptr,
223 * If all went well, we need to return the FDT address to the
224 * calling function so it can be passed to kernel as part of
225 * the kernel boot protocol.
227 if (status == EFI_SUCCESS)
230 pr_efi_err(sys_table, "Failed to update FDT and exit boot services\n");
232 efi_free(sys_table, initrd_size, initrd_addr);
233 efi_free(sys_table, fdt_size, fdt_addr);
236 efi_free(sys_table, image_size, *image_addr);
237 efi_free(sys_table, reserve_size, reserve_addr);
239 free_screen_info(sys_table, si);
240 efi_free(sys_table, cmdline_size, (unsigned long)cmdline_ptr);
246 * This is the base address at which to start allocating virtual memory ranges
247 * for UEFI Runtime Services. This is in the low TTBR0 range so that we can use
248 * any allocation we choose, and eliminate the risk of a conflict after kexec.
249 * The value chosen is the largest non-zero power of 2 suitable for this purpose
250 * both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can
251 * be mapped efficiently.
252 * Since 32-bit ARM could potentially execute with a 1G/3G user/kernel split,
253 * map everything below 1 GB.
255 #define EFI_RT_VIRTUAL_BASE SZ_512M
257 static int cmp_mem_desc(const void *l, const void *r)
259 const efi_memory_desc_t *left = l, *right = r;
261 return (left->phys_addr > right->phys_addr) ? 1 : -1;
265 * Returns whether region @left ends exactly where region @right starts,
266 * or false if either argument is NULL.
268 static bool regions_are_adjacent(efi_memory_desc_t *left,
269 efi_memory_desc_t *right)
273 if (left == NULL || right == NULL)
276 left_end = left->phys_addr + left->num_pages * EFI_PAGE_SIZE;
278 return left_end == right->phys_addr;
282 * Returns whether region @left and region @right have compatible memory type
283 * mapping attributes, and are both EFI_MEMORY_RUNTIME regions.
285 static bool regions_have_compatible_memory_type_attrs(efi_memory_desc_t *left,
286 efi_memory_desc_t *right)
288 static const u64 mem_type_mask = EFI_MEMORY_WB | EFI_MEMORY_WT |
289 EFI_MEMORY_WC | EFI_MEMORY_UC |
292 return ((left->attribute ^ right->attribute) & mem_type_mask) == 0;
296 * efi_get_virtmap() - create a virtual mapping for the EFI memory map
298 * This function populates the virt_addr fields of all memory region descriptors
299 * in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors
300 * are also copied to @runtime_map, and their total count is returned in @count.
302 void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
303 unsigned long desc_size, efi_memory_desc_t *runtime_map,
306 u64 efi_virt_base = EFI_RT_VIRTUAL_BASE;
307 efi_memory_desc_t *in, *prev = NULL, *out = runtime_map;
311 * To work around potential issues with the Properties Table feature
312 * introduced in UEFI 2.5, which may split PE/COFF executable images
313 * in memory into several RuntimeServicesCode and RuntimeServicesData
314 * regions, we need to preserve the relative offsets between adjacent
315 * EFI_MEMORY_RUNTIME regions with the same memory type attributes.
316 * The easiest way to find adjacent regions is to sort the memory map
317 * before traversing it.
319 sort(memory_map, map_size / desc_size, desc_size, cmp_mem_desc, NULL);
321 for (l = 0; l < map_size; l += desc_size, prev = in) {
324 in = (void *)memory_map + l;
325 if (!(in->attribute & EFI_MEMORY_RUNTIME))
328 paddr = in->phys_addr;
329 size = in->num_pages * EFI_PAGE_SIZE;
332 * Make the mapping compatible with 64k pages: this allows
333 * a 4k page size kernel to kexec a 64k page size kernel and
336 if (!regions_are_adjacent(prev, in) ||
337 !regions_have_compatible_memory_type_attrs(prev, in)) {
339 paddr = round_down(in->phys_addr, SZ_64K);
340 size += in->phys_addr - paddr;
343 * Avoid wasting memory on PTEs by choosing a virtual
344 * base that is compatible with section mappings if this
345 * region has the appropriate size and physical
346 * alignment. (Sections are 2 MB on 4k granule kernels)
348 if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M)
349 efi_virt_base = round_up(efi_virt_base, SZ_2M);
351 efi_virt_base = round_up(efi_virt_base, SZ_64K);
354 in->virt_addr = efi_virt_base + in->phys_addr - paddr;
355 efi_virt_base += size;
357 memcpy(out, in, desc_size);
358 out = (void *)out + desc_size;