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>
23 static int efi_get_secureboot(efi_system_table_t *sys_table_arg)
25 static efi_char16_t const sb_var_name[] = {
26 'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0 };
27 static efi_char16_t const sm_var_name[] = {
28 'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0 };
30 efi_guid_t var_guid = EFI_GLOBAL_VARIABLE_GUID;
31 efi_get_variable_t *f_getvar = sys_table_arg->runtime->get_variable;
33 unsigned long size = sizeof(val);
36 status = f_getvar((efi_char16_t *)sb_var_name, (efi_guid_t *)&var_guid,
39 if (status != EFI_SUCCESS)
45 status = f_getvar((efi_char16_t *)sm_var_name, (efi_guid_t *)&var_guid,
48 if (status != EFI_SUCCESS)
60 case EFI_DEVICE_ERROR:
62 case EFI_SECURITY_VIOLATION:
69 efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
70 void *__image, void **__fh)
72 efi_file_io_interface_t *io;
73 efi_loaded_image_t *image = __image;
74 efi_file_handle_t *fh;
75 efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
77 void *handle = (void *)(unsigned long)image->device_handle;
79 status = sys_table_arg->boottime->handle_protocol(handle,
80 &fs_proto, (void **)&io);
81 if (status != EFI_SUCCESS) {
82 efi_printk(sys_table_arg, "Failed to handle fs_proto\n");
86 status = io->open_volume(io, &fh);
87 if (status != EFI_SUCCESS)
88 efi_printk(sys_table_arg, "Failed to open volume\n");
94 void efi_char16_printk(efi_system_table_t *sys_table_arg,
97 struct efi_simple_text_output_protocol *out;
99 out = (struct efi_simple_text_output_protocol *)sys_table_arg->con_out;
100 out->output_string(out, str);
103 static struct screen_info *setup_graphics(efi_system_table_t *sys_table_arg)
105 efi_guid_t gop_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
108 void **gop_handle = NULL;
109 struct screen_info *si = NULL;
112 status = efi_call_early(locate_handle, EFI_LOCATE_BY_PROTOCOL,
113 &gop_proto, NULL, &size, gop_handle);
114 if (status == EFI_BUFFER_TOO_SMALL) {
115 si = alloc_screen_info(sys_table_arg);
118 efi_setup_gop(sys_table_arg, si, &gop_proto, size);
124 * This function handles the architcture specific differences between arm and
125 * arm64 regarding where the kernel image must be loaded and any memory that
126 * must be reserved. On failure it is required to free all
127 * all allocations it has made.
129 efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
130 unsigned long *image_addr,
131 unsigned long *image_size,
132 unsigned long *reserve_addr,
133 unsigned long *reserve_size,
134 unsigned long dram_base,
135 efi_loaded_image_t *image);
137 * EFI entry point for the arm/arm64 EFI stubs. This is the entrypoint
138 * that is described in the PE/COFF header. Most of the code is the same
139 * for both archictectures, with the arch-specific code provided in the
140 * handle_kernel_image() function.
142 unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
143 unsigned long *image_addr)
145 efi_loaded_image_t *image;
147 unsigned long image_size = 0;
148 unsigned long dram_base;
149 /* addr/point and size pairs for memory management*/
150 unsigned long initrd_addr;
152 unsigned long fdt_addr = 0; /* Original DTB */
153 unsigned long fdt_size = 0;
154 char *cmdline_ptr = NULL;
155 int cmdline_size = 0;
156 unsigned long new_fdt_addr;
157 efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
158 unsigned long reserve_addr = 0;
159 unsigned long reserve_size = 0;
161 struct screen_info *si;
163 /* Check if we were booted by the EFI firmware */
164 if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
167 pr_efi(sys_table, "Booting Linux Kernel...\n");
169 status = check_platform_features(sys_table);
170 if (status != EFI_SUCCESS)
174 * Get a handle to the loaded image protocol. This is used to get
175 * information about the running image, such as size and the command
178 status = sys_table->boottime->handle_protocol(handle,
179 &loaded_image_proto, (void *)&image);
180 if (status != EFI_SUCCESS) {
181 pr_efi_err(sys_table, "Failed to get loaded image protocol\n");
185 dram_base = get_dram_base(sys_table);
186 if (dram_base == EFI_ERROR) {
187 pr_efi_err(sys_table, "Failed to find DRAM base\n");
192 * Get the command line from EFI, using the LOADED_IMAGE
193 * protocol. We are going to copy the command line into the
194 * device tree, so this can be allocated anywhere.
196 cmdline_ptr = efi_convert_cmdline(sys_table, image, &cmdline_size);
198 pr_efi_err(sys_table, "getting command line via LOADED_IMAGE_PROTOCOL\n");
202 /* check whether 'nokaslr' was passed on the command line */
203 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
204 static const u8 default_cmdline[] = CONFIG_CMDLINE;
205 const u8 *str, *cmdline = cmdline_ptr;
207 if (IS_ENABLED(CONFIG_CMDLINE_FORCE))
208 cmdline = default_cmdline;
209 str = strstr(cmdline, "nokaslr");
210 if (str == cmdline || (str > cmdline && *(str - 1) == ' '))
214 si = setup_graphics(sys_table);
216 status = handle_kernel_image(sys_table, image_addr, &image_size,
220 if (status != EFI_SUCCESS) {
221 pr_efi_err(sys_table, "Failed to relocate kernel\n");
222 goto fail_free_cmdline;
225 status = efi_parse_options(cmdline_ptr);
226 if (status != EFI_SUCCESS)
227 pr_efi_err(sys_table, "Failed to parse EFI cmdline options\n");
229 secure_boot = efi_get_secureboot(sys_table);
231 pr_efi(sys_table, "UEFI Secure Boot is enabled.\n");
233 if (secure_boot < 0) {
234 pr_efi_err(sys_table,
235 "could not determine UEFI Secure Boot status.\n");
239 * Unauthenticated device tree data is a security hazard, so
240 * ignore 'dtb=' unless UEFI Secure Boot is disabled.
242 if (secure_boot != 0 && strstr(cmdline_ptr, "dtb=")) {
243 pr_efi(sys_table, "Ignoring DTB from command line.\n");
245 status = handle_cmdline_files(sys_table, image, cmdline_ptr,
247 ~0UL, &fdt_addr, &fdt_size);
249 if (status != EFI_SUCCESS) {
250 pr_efi_err(sys_table, "Failed to load device tree!\n");
251 goto fail_free_image;
256 pr_efi(sys_table, "Using DTB from command line\n");
258 /* Look for a device tree configuration table entry. */
259 fdt_addr = (uintptr_t)get_fdt(sys_table, &fdt_size);
261 pr_efi(sys_table, "Using DTB from configuration table\n");
265 pr_efi(sys_table, "Generating empty DTB\n");
267 status = handle_cmdline_files(sys_table, image, cmdline_ptr,
268 "initrd=", dram_base + SZ_512M,
269 (unsigned long *)&initrd_addr,
270 (unsigned long *)&initrd_size);
271 if (status != EFI_SUCCESS)
272 pr_efi_err(sys_table, "Failed initrd from command line!\n");
274 efi_random_get_seed(sys_table);
276 new_fdt_addr = fdt_addr;
277 status = allocate_new_fdt_and_exit_boot(sys_table, handle,
278 &new_fdt_addr, dram_base + MAX_FDT_OFFSET,
279 initrd_addr, initrd_size, cmdline_ptr,
283 * If all went well, we need to return the FDT address to the
284 * calling function so it can be passed to kernel as part of
285 * the kernel boot protocol.
287 if (status == EFI_SUCCESS)
290 pr_efi_err(sys_table, "Failed to update FDT and exit boot services\n");
292 efi_free(sys_table, initrd_size, initrd_addr);
293 efi_free(sys_table, fdt_size, fdt_addr);
296 efi_free(sys_table, image_size, *image_addr);
297 efi_free(sys_table, reserve_size, reserve_addr);
299 free_screen_info(sys_table, si);
300 efi_free(sys_table, cmdline_size, (unsigned long)cmdline_ptr);
306 * This is the base address at which to start allocating virtual memory ranges
307 * for UEFI Runtime Services. This is in the low TTBR0 range so that we can use
308 * any allocation we choose, and eliminate the risk of a conflict after kexec.
309 * The value chosen is the largest non-zero power of 2 suitable for this purpose
310 * both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can
311 * be mapped efficiently.
312 * Since 32-bit ARM could potentially execute with a 1G/3G user/kernel split,
313 * map everything below 1 GB.
315 #define EFI_RT_VIRTUAL_BASE SZ_512M
317 static int cmp_mem_desc(const void *l, const void *r)
319 const efi_memory_desc_t *left = l, *right = r;
321 return (left->phys_addr > right->phys_addr) ? 1 : -1;
325 * Returns whether region @left ends exactly where region @right starts,
326 * or false if either argument is NULL.
328 static bool regions_are_adjacent(efi_memory_desc_t *left,
329 efi_memory_desc_t *right)
333 if (left == NULL || right == NULL)
336 left_end = left->phys_addr + left->num_pages * EFI_PAGE_SIZE;
338 return left_end == right->phys_addr;
342 * Returns whether region @left and region @right have compatible memory type
343 * mapping attributes, and are both EFI_MEMORY_RUNTIME regions.
345 static bool regions_have_compatible_memory_type_attrs(efi_memory_desc_t *left,
346 efi_memory_desc_t *right)
348 static const u64 mem_type_mask = EFI_MEMORY_WB | EFI_MEMORY_WT |
349 EFI_MEMORY_WC | EFI_MEMORY_UC |
352 return ((left->attribute ^ right->attribute) & mem_type_mask) == 0;
356 * efi_get_virtmap() - create a virtual mapping for the EFI memory map
358 * This function populates the virt_addr fields of all memory region descriptors
359 * in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors
360 * are also copied to @runtime_map, and their total count is returned in @count.
362 void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
363 unsigned long desc_size, efi_memory_desc_t *runtime_map,
366 u64 efi_virt_base = EFI_RT_VIRTUAL_BASE;
367 efi_memory_desc_t *in, *prev = NULL, *out = runtime_map;
371 * To work around potential issues with the Properties Table feature
372 * introduced in UEFI 2.5, which may split PE/COFF executable images
373 * in memory into several RuntimeServicesCode and RuntimeServicesData
374 * regions, we need to preserve the relative offsets between adjacent
375 * EFI_MEMORY_RUNTIME regions with the same memory type attributes.
376 * The easiest way to find adjacent regions is to sort the memory map
377 * before traversing it.
379 sort(memory_map, map_size / desc_size, desc_size, cmp_mem_desc, NULL);
381 for (l = 0; l < map_size; l += desc_size, prev = in) {
384 in = (void *)memory_map + l;
385 if (!(in->attribute & EFI_MEMORY_RUNTIME))
388 paddr = in->phys_addr;
389 size = in->num_pages * EFI_PAGE_SIZE;
392 * Make the mapping compatible with 64k pages: this allows
393 * a 4k page size kernel to kexec a 64k page size kernel and
396 if (!regions_are_adjacent(prev, in) ||
397 !regions_have_compatible_memory_type_attrs(prev, in)) {
399 paddr = round_down(in->phys_addr, SZ_64K);
400 size += in->phys_addr - paddr;
403 * Avoid wasting memory on PTEs by choosing a virtual
404 * base that is compatible with section mappings if this
405 * region has the appropriate size and physical
406 * alignment. (Sections are 2 MB on 4k granule kernels)
408 if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M)
409 efi_virt_base = round_up(efi_virt_base, SZ_2M);
411 efi_virt_base = round_up(efi_virt_base, SZ_64K);
414 in->virt_addr = efi_virt_base + in->phys_addr - paddr;
415 efi_virt_base += size;
417 memcpy(out, in, desc_size);
418 out = (void *)out + desc_size;