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>
22 static int efi_get_secureboot(efi_system_table_t *sys_table_arg)
24 static efi_char16_t const sb_var_name[] = {
25 'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0 };
26 static efi_char16_t const sm_var_name[] = {
27 'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0 };
29 efi_guid_t var_guid = EFI_GLOBAL_VARIABLE_GUID;
30 efi_get_variable_t *f_getvar = sys_table_arg->runtime->get_variable;
32 unsigned long size = sizeof(val);
35 status = f_getvar((efi_char16_t *)sb_var_name, (efi_guid_t *)&var_guid,
38 if (status != EFI_SUCCESS)
44 status = f_getvar((efi_char16_t *)sm_var_name, (efi_guid_t *)&var_guid,
47 if (status != EFI_SUCCESS)
59 case EFI_DEVICE_ERROR:
61 case EFI_SECURITY_VIOLATION:
68 efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
69 void *__image, void **__fh)
71 efi_file_io_interface_t *io;
72 efi_loaded_image_t *image = __image;
73 efi_file_handle_t *fh;
74 efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
76 void *handle = (void *)(unsigned long)image->device_handle;
78 status = sys_table_arg->boottime->handle_protocol(handle,
79 &fs_proto, (void **)&io);
80 if (status != EFI_SUCCESS) {
81 efi_printk(sys_table_arg, "Failed to handle fs_proto\n");
85 status = io->open_volume(io, &fh);
86 if (status != EFI_SUCCESS)
87 efi_printk(sys_table_arg, "Failed to open volume\n");
93 efi_status_t efi_file_close(void *handle)
95 efi_file_handle_t *fh = handle;
97 return fh->close(handle);
101 efi_file_read(void *handle, unsigned long *size, void *addr)
103 efi_file_handle_t *fh = handle;
105 return fh->read(handle, size, addr);
110 efi_file_size(efi_system_table_t *sys_table_arg, void *__fh,
111 efi_char16_t *filename_16, void **handle, u64 *file_sz)
113 efi_file_handle_t *h, *fh = __fh;
114 efi_file_info_t *info;
116 efi_guid_t info_guid = EFI_FILE_INFO_ID;
117 unsigned long info_sz;
119 status = fh->open(fh, &h, filename_16, EFI_FILE_MODE_READ, (u64)0);
120 if (status != EFI_SUCCESS) {
121 efi_printk(sys_table_arg, "Failed to open file: ");
122 efi_char16_printk(sys_table_arg, filename_16);
123 efi_printk(sys_table_arg, "\n");
130 status = h->get_info(h, &info_guid, &info_sz, NULL);
131 if (status != EFI_BUFFER_TOO_SMALL) {
132 efi_printk(sys_table_arg, "Failed to get file info size\n");
137 status = sys_table_arg->boottime->allocate_pool(EFI_LOADER_DATA,
138 info_sz, (void **)&info);
139 if (status != EFI_SUCCESS) {
140 efi_printk(sys_table_arg, "Failed to alloc mem for file info\n");
144 status = h->get_info(h, &info_guid, &info_sz,
146 if (status == EFI_BUFFER_TOO_SMALL) {
147 sys_table_arg->boottime->free_pool(info);
151 *file_sz = info->file_size;
152 sys_table_arg->boottime->free_pool(info);
154 if (status != EFI_SUCCESS)
155 efi_printk(sys_table_arg, "Failed to get initrd info\n");
162 void efi_char16_printk(efi_system_table_t *sys_table_arg,
165 struct efi_simple_text_output_protocol *out;
167 out = (struct efi_simple_text_output_protocol *)sys_table_arg->con_out;
168 out->output_string(out, str);
171 static struct screen_info *setup_graphics(efi_system_table_t *sys_table_arg)
173 efi_guid_t gop_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
176 void **gop_handle = NULL;
177 struct screen_info *si = NULL;
180 status = efi_call_early(locate_handle, EFI_LOCATE_BY_PROTOCOL,
181 &gop_proto, NULL, &size, gop_handle);
182 if (status == EFI_BUFFER_TOO_SMALL) {
183 si = alloc_screen_info(sys_table_arg);
186 efi_setup_gop(sys_table_arg, si, &gop_proto, size);
192 * This function handles the architcture specific differences between arm and
193 * arm64 regarding where the kernel image must be loaded and any memory that
194 * must be reserved. On failure it is required to free all
195 * all allocations it has made.
197 efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
198 unsigned long *image_addr,
199 unsigned long *image_size,
200 unsigned long *reserve_addr,
201 unsigned long *reserve_size,
202 unsigned long dram_base,
203 efi_loaded_image_t *image);
205 * EFI entry point for the arm/arm64 EFI stubs. This is the entrypoint
206 * that is described in the PE/COFF header. Most of the code is the same
207 * for both archictectures, with the arch-specific code provided in the
208 * handle_kernel_image() function.
210 unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
211 unsigned long *image_addr)
213 efi_loaded_image_t *image;
215 unsigned long image_size = 0;
216 unsigned long dram_base;
217 /* addr/point and size pairs for memory management*/
218 unsigned long initrd_addr;
220 unsigned long fdt_addr = 0; /* Original DTB */
221 unsigned long fdt_size = 0;
222 char *cmdline_ptr = NULL;
223 int cmdline_size = 0;
224 unsigned long new_fdt_addr;
225 efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
226 unsigned long reserve_addr = 0;
227 unsigned long reserve_size = 0;
229 struct screen_info *si;
231 /* Check if we were booted by the EFI firmware */
232 if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
235 pr_efi(sys_table, "Booting Linux Kernel...\n");
237 status = check_platform_features(sys_table);
238 if (status != EFI_SUCCESS)
242 * Get a handle to the loaded image protocol. This is used to get
243 * information about the running image, such as size and the command
246 status = sys_table->boottime->handle_protocol(handle,
247 &loaded_image_proto, (void *)&image);
248 if (status != EFI_SUCCESS) {
249 pr_efi_err(sys_table, "Failed to get loaded image protocol\n");
253 dram_base = get_dram_base(sys_table);
254 if (dram_base == EFI_ERROR) {
255 pr_efi_err(sys_table, "Failed to find DRAM base\n");
260 * Get the command line from EFI, using the LOADED_IMAGE
261 * protocol. We are going to copy the command line into the
262 * device tree, so this can be allocated anywhere.
264 cmdline_ptr = efi_convert_cmdline(sys_table, image, &cmdline_size);
266 pr_efi_err(sys_table, "getting command line via LOADED_IMAGE_PROTOCOL\n");
270 si = setup_graphics(sys_table);
272 status = handle_kernel_image(sys_table, image_addr, &image_size,
276 if (status != EFI_SUCCESS) {
277 pr_efi_err(sys_table, "Failed to relocate kernel\n");
278 goto fail_free_cmdline;
281 if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) ||
282 IS_ENABLED(CONFIG_CMDLINE_FORCE) ||
284 efi_parse_options(CONFIG_CMDLINE);
286 if (!IS_ENABLED(CONFIG_CMDLINE_FORCE) && cmdline_size > 0)
287 efi_parse_options(cmdline_ptr);
289 secure_boot = efi_get_secureboot(sys_table);
291 pr_efi(sys_table, "UEFI Secure Boot is enabled.\n");
293 if (secure_boot < 0) {
294 pr_efi_err(sys_table,
295 "could not determine UEFI Secure Boot status.\n");
299 * Unauthenticated device tree data is a security hazard, so
300 * ignore 'dtb=' unless UEFI Secure Boot is disabled.
302 if (secure_boot != 0 && strstr(cmdline_ptr, "dtb=")) {
303 pr_efi(sys_table, "Ignoring DTB from command line.\n");
305 status = handle_cmdline_files(sys_table, image, cmdline_ptr,
307 ~0UL, &fdt_addr, &fdt_size);
309 if (status != EFI_SUCCESS) {
310 pr_efi_err(sys_table, "Failed to load device tree!\n");
311 goto fail_free_image;
316 pr_efi(sys_table, "Using DTB from command line\n");
318 /* Look for a device tree configuration table entry. */
319 fdt_addr = (uintptr_t)get_fdt(sys_table, &fdt_size);
321 pr_efi(sys_table, "Using DTB from configuration table\n");
325 pr_efi(sys_table, "Generating empty DTB\n");
327 status = handle_cmdline_files(sys_table, image, cmdline_ptr,
328 "initrd=", dram_base + SZ_512M,
329 (unsigned long *)&initrd_addr,
330 (unsigned long *)&initrd_size);
331 if (status != EFI_SUCCESS)
332 pr_efi_err(sys_table, "Failed initrd from command line!\n");
334 new_fdt_addr = fdt_addr;
335 status = allocate_new_fdt_and_exit_boot(sys_table, handle,
336 &new_fdt_addr, dram_base + MAX_FDT_OFFSET,
337 initrd_addr, initrd_size, cmdline_ptr,
341 * If all went well, we need to return the FDT address to the
342 * calling function so it can be passed to kernel as part of
343 * the kernel boot protocol.
345 if (status == EFI_SUCCESS)
348 pr_efi_err(sys_table, "Failed to update FDT and exit boot services\n");
350 efi_free(sys_table, initrd_size, initrd_addr);
351 efi_free(sys_table, fdt_size, fdt_addr);
354 efi_free(sys_table, image_size, *image_addr);
355 efi_free(sys_table, reserve_size, reserve_addr);
357 free_screen_info(sys_table, si);
358 efi_free(sys_table, cmdline_size, (unsigned long)cmdline_ptr);
364 * This is the base address at which to start allocating virtual memory ranges
365 * for UEFI Runtime Services. This is in the low TTBR0 range so that we can use
366 * any allocation we choose, and eliminate the risk of a conflict after kexec.
367 * The value chosen is the largest non-zero power of 2 suitable for this purpose
368 * both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can
369 * be mapped efficiently.
370 * Since 32-bit ARM could potentially execute with a 1G/3G user/kernel split,
371 * map everything below 1 GB.
373 #define EFI_RT_VIRTUAL_BASE SZ_512M
375 static int cmp_mem_desc(const void *l, const void *r)
377 const efi_memory_desc_t *left = l, *right = r;
379 return (left->phys_addr > right->phys_addr) ? 1 : -1;
383 * Returns whether region @left ends exactly where region @right starts,
384 * or false if either argument is NULL.
386 static bool regions_are_adjacent(efi_memory_desc_t *left,
387 efi_memory_desc_t *right)
391 if (left == NULL || right == NULL)
394 left_end = left->phys_addr + left->num_pages * EFI_PAGE_SIZE;
396 return left_end == right->phys_addr;
400 * Returns whether region @left and region @right have compatible memory type
401 * mapping attributes, and are both EFI_MEMORY_RUNTIME regions.
403 static bool regions_have_compatible_memory_type_attrs(efi_memory_desc_t *left,
404 efi_memory_desc_t *right)
406 static const u64 mem_type_mask = EFI_MEMORY_WB | EFI_MEMORY_WT |
407 EFI_MEMORY_WC | EFI_MEMORY_UC |
410 return ((left->attribute ^ right->attribute) & mem_type_mask) == 0;
414 * efi_get_virtmap() - create a virtual mapping for the EFI memory map
416 * This function populates the virt_addr fields of all memory region descriptors
417 * in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors
418 * are also copied to @runtime_map, and their total count is returned in @count.
420 void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
421 unsigned long desc_size, efi_memory_desc_t *runtime_map,
424 u64 efi_virt_base = EFI_RT_VIRTUAL_BASE;
425 efi_memory_desc_t *in, *prev = NULL, *out = runtime_map;
429 * To work around potential issues with the Properties Table feature
430 * introduced in UEFI 2.5, which may split PE/COFF executable images
431 * in memory into several RuntimeServicesCode and RuntimeServicesData
432 * regions, we need to preserve the relative offsets between adjacent
433 * EFI_MEMORY_RUNTIME regions with the same memory type attributes.
434 * The easiest way to find adjacent regions is to sort the memory map
435 * before traversing it.
437 sort(memory_map, map_size / desc_size, desc_size, cmp_mem_desc, NULL);
439 for (l = 0; l < map_size; l += desc_size, prev = in) {
442 in = (void *)memory_map + l;
443 if (!(in->attribute & EFI_MEMORY_RUNTIME))
446 paddr = in->phys_addr;
447 size = in->num_pages * EFI_PAGE_SIZE;
450 * Make the mapping compatible with 64k pages: this allows
451 * a 4k page size kernel to kexec a 64k page size kernel and
454 if (!regions_are_adjacent(prev, in) ||
455 !regions_have_compatible_memory_type_attrs(prev, in)) {
457 paddr = round_down(in->phys_addr, SZ_64K);
458 size += in->phys_addr - paddr;
461 * Avoid wasting memory on PTEs by choosing a virtual
462 * base that is compatible with section mappings if this
463 * region has the appropriate size and physical
464 * alignment. (Sections are 2 MB on 4k granule kernels)
466 if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M)
467 efi_virt_base = round_up(efi_virt_base, SZ_2M);
469 efi_virt_base = round_up(efi_virt_base, SZ_64K);
472 in->virt_addr = efi_virt_base + in->phys_addr - paddr;
473 efi_virt_base += size;
475 memcpy(out, in, desc_size);
476 out = (void *)out + desc_size;