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 efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
24 void *__image, void **__fh)
26 efi_file_io_interface_t *io;
27 efi_loaded_image_t *image = __image;
28 efi_file_handle_t *fh;
29 efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
31 void *handle = (void *)(unsigned long)image->device_handle;
33 status = sys_table_arg->boottime->handle_protocol(handle,
34 &fs_proto, (void **)&io);
35 if (status != EFI_SUCCESS) {
36 efi_printk(sys_table_arg, "Failed to handle fs_proto\n");
40 status = io->open_volume(io, &fh);
41 if (status != EFI_SUCCESS)
42 efi_printk(sys_table_arg, "Failed to open volume\n");
48 void efi_char16_printk(efi_system_table_t *sys_table_arg,
51 struct efi_simple_text_output_protocol *out;
53 out = (struct efi_simple_text_output_protocol *)sys_table_arg->con_out;
54 out->output_string(out, str);
57 static struct screen_info *setup_graphics(efi_system_table_t *sys_table_arg)
59 efi_guid_t gop_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
62 void **gop_handle = NULL;
63 struct screen_info *si = NULL;
66 status = efi_call_early(locate_handle, EFI_LOCATE_BY_PROTOCOL,
67 &gop_proto, NULL, &size, gop_handle);
68 if (status == EFI_BUFFER_TOO_SMALL) {
69 si = alloc_screen_info(sys_table_arg);
72 efi_setup_gop(sys_table_arg, si, &gop_proto, size);
78 * This function handles the architcture specific differences between arm and
79 * arm64 regarding where the kernel image must be loaded and any memory that
80 * must be reserved. On failure it is required to free all
81 * all allocations it has made.
83 efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
84 unsigned long *image_addr,
85 unsigned long *image_size,
86 unsigned long *reserve_addr,
87 unsigned long *reserve_size,
88 unsigned long dram_base,
89 efi_loaded_image_t *image);
91 * EFI entry point for the arm/arm64 EFI stubs. This is the entrypoint
92 * that is described in the PE/COFF header. Most of the code is the same
93 * for both archictectures, with the arch-specific code provided in the
94 * handle_kernel_image() function.
96 unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
97 unsigned long *image_addr)
99 efi_loaded_image_t *image;
101 unsigned long image_size = 0;
102 unsigned long dram_base;
103 /* addr/point and size pairs for memory management*/
104 unsigned long initrd_addr;
106 unsigned long fdt_addr = 0; /* Original DTB */
107 unsigned long fdt_size = 0;
108 char *cmdline_ptr = NULL;
109 int cmdline_size = 0;
110 unsigned long new_fdt_addr;
111 efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
112 unsigned long reserve_addr = 0;
113 unsigned long reserve_size = 0;
114 enum efi_secureboot_mode secure_boot;
115 struct screen_info *si;
117 /* Check if we were booted by the EFI firmware */
118 if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
121 pr_efi(sys_table, "Booting Linux Kernel...\n");
123 status = check_platform_features(sys_table);
124 if (status != EFI_SUCCESS)
128 * Get a handle to the loaded image protocol. This is used to get
129 * information about the running image, such as size and the command
132 status = sys_table->boottime->handle_protocol(handle,
133 &loaded_image_proto, (void *)&image);
134 if (status != EFI_SUCCESS) {
135 pr_efi_err(sys_table, "Failed to get loaded image protocol\n");
139 dram_base = get_dram_base(sys_table);
140 if (dram_base == EFI_ERROR) {
141 pr_efi_err(sys_table, "Failed to find DRAM base\n");
146 * Get the command line from EFI, using the LOADED_IMAGE
147 * protocol. We are going to copy the command line into the
148 * device tree, so this can be allocated anywhere.
150 cmdline_ptr = efi_convert_cmdline(sys_table, image, &cmdline_size);
152 pr_efi_err(sys_table, "getting command line via LOADED_IMAGE_PROTOCOL\n");
156 /* check whether 'nokaslr' was passed on the command line */
157 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
158 static const u8 default_cmdline[] = CONFIG_CMDLINE;
159 const u8 *str, *cmdline = cmdline_ptr;
161 if (IS_ENABLED(CONFIG_CMDLINE_FORCE))
162 cmdline = default_cmdline;
163 str = strstr(cmdline, "nokaslr");
164 if (str == cmdline || (str > cmdline && *(str - 1) == ' '))
168 si = setup_graphics(sys_table);
170 status = handle_kernel_image(sys_table, image_addr, &image_size,
174 if (status != EFI_SUCCESS) {
175 pr_efi_err(sys_table, "Failed to relocate kernel\n");
176 goto fail_free_cmdline;
179 status = efi_parse_options(cmdline_ptr);
180 if (status != EFI_SUCCESS)
181 pr_efi_err(sys_table, "Failed to parse EFI cmdline options\n");
183 secure_boot = efi_get_secureboot(sys_table);
186 * Unauthenticated device tree data is a security hazard, so ignore
187 * 'dtb=' unless UEFI Secure Boot is disabled. We assume that secure
188 * boot is enabled if we can't determine its state.
190 if (secure_boot != efi_secureboot_mode_disabled &&
191 strstr(cmdline_ptr, "dtb=")) {
192 pr_efi(sys_table, "Ignoring DTB from command line.\n");
194 status = handle_cmdline_files(sys_table, image, cmdline_ptr,
196 ~0UL, &fdt_addr, &fdt_size);
198 if (status != EFI_SUCCESS) {
199 pr_efi_err(sys_table, "Failed to load device tree!\n");
200 goto fail_free_image;
205 pr_efi(sys_table, "Using DTB from command line\n");
207 /* Look for a device tree configuration table entry. */
208 fdt_addr = (uintptr_t)get_fdt(sys_table, &fdt_size);
210 pr_efi(sys_table, "Using DTB from configuration table\n");
214 pr_efi(sys_table, "Generating empty DTB\n");
216 status = handle_cmdline_files(sys_table, image, cmdline_ptr,
217 "initrd=", dram_base + SZ_512M,
218 (unsigned long *)&initrd_addr,
219 (unsigned long *)&initrd_size);
220 if (status != EFI_SUCCESS)
221 pr_efi_err(sys_table, "Failed initrd from command line!\n");
223 efi_random_get_seed(sys_table);
225 new_fdt_addr = fdt_addr;
226 status = allocate_new_fdt_and_exit_boot(sys_table, handle,
227 &new_fdt_addr, dram_base + MAX_FDT_OFFSET,
228 initrd_addr, initrd_size, cmdline_ptr,
232 * If all went well, we need to return the FDT address to the
233 * calling function so it can be passed to kernel as part of
234 * the kernel boot protocol.
236 if (status == EFI_SUCCESS)
239 pr_efi_err(sys_table, "Failed to update FDT and exit boot services\n");
241 efi_free(sys_table, initrd_size, initrd_addr);
242 efi_free(sys_table, fdt_size, fdt_addr);
245 efi_free(sys_table, image_size, *image_addr);
246 efi_free(sys_table, reserve_size, reserve_addr);
248 free_screen_info(sys_table, si);
249 efi_free(sys_table, cmdline_size, (unsigned long)cmdline_ptr);
255 * This is the base address at which to start allocating virtual memory ranges
256 * for UEFI Runtime Services. This is in the low TTBR0 range so that we can use
257 * any allocation we choose, and eliminate the risk of a conflict after kexec.
258 * The value chosen is the largest non-zero power of 2 suitable for this purpose
259 * both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can
260 * be mapped efficiently.
261 * Since 32-bit ARM could potentially execute with a 1G/3G user/kernel split,
262 * map everything below 1 GB.
264 #define EFI_RT_VIRTUAL_BASE SZ_512M
266 static int cmp_mem_desc(const void *l, const void *r)
268 const efi_memory_desc_t *left = l, *right = r;
270 return (left->phys_addr > right->phys_addr) ? 1 : -1;
274 * Returns whether region @left ends exactly where region @right starts,
275 * or false if either argument is NULL.
277 static bool regions_are_adjacent(efi_memory_desc_t *left,
278 efi_memory_desc_t *right)
282 if (left == NULL || right == NULL)
285 left_end = left->phys_addr + left->num_pages * EFI_PAGE_SIZE;
287 return left_end == right->phys_addr;
291 * Returns whether region @left and region @right have compatible memory type
292 * mapping attributes, and are both EFI_MEMORY_RUNTIME regions.
294 static bool regions_have_compatible_memory_type_attrs(efi_memory_desc_t *left,
295 efi_memory_desc_t *right)
297 static const u64 mem_type_mask = EFI_MEMORY_WB | EFI_MEMORY_WT |
298 EFI_MEMORY_WC | EFI_MEMORY_UC |
301 return ((left->attribute ^ right->attribute) & mem_type_mask) == 0;
305 * efi_get_virtmap() - create a virtual mapping for the EFI memory map
307 * This function populates the virt_addr fields of all memory region descriptors
308 * in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors
309 * are also copied to @runtime_map, and their total count is returned in @count.
311 void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
312 unsigned long desc_size, efi_memory_desc_t *runtime_map,
315 u64 efi_virt_base = EFI_RT_VIRTUAL_BASE;
316 efi_memory_desc_t *in, *prev = NULL, *out = runtime_map;
320 * To work around potential issues with the Properties Table feature
321 * introduced in UEFI 2.5, which may split PE/COFF executable images
322 * in memory into several RuntimeServicesCode and RuntimeServicesData
323 * regions, we need to preserve the relative offsets between adjacent
324 * EFI_MEMORY_RUNTIME regions with the same memory type attributes.
325 * The easiest way to find adjacent regions is to sort the memory map
326 * before traversing it.
328 sort(memory_map, map_size / desc_size, desc_size, cmp_mem_desc, NULL);
330 for (l = 0; l < map_size; l += desc_size, prev = in) {
333 in = (void *)memory_map + l;
334 if (!(in->attribute & EFI_MEMORY_RUNTIME))
337 paddr = in->phys_addr;
338 size = in->num_pages * EFI_PAGE_SIZE;
341 * Make the mapping compatible with 64k pages: this allows
342 * a 4k page size kernel to kexec a 64k page size kernel and
345 if (!regions_are_adjacent(prev, in) ||
346 !regions_have_compatible_memory_type_attrs(prev, in)) {
348 paddr = round_down(in->phys_addr, SZ_64K);
349 size += in->phys_addr - paddr;
352 * Avoid wasting memory on PTEs by choosing a virtual
353 * base that is compatible with section mappings if this
354 * region has the appropriate size and physical
355 * alignment. (Sections are 2 MB on 4k granule kernels)
357 if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M)
358 efi_virt_base = round_up(efi_virt_base, SZ_2M);
360 efi_virt_base = round_up(efi_virt_base, SZ_64K);
363 in->virt_addr = efi_virt_base + in->phys_addr - paddr;
364 efi_virt_base += size;
366 memcpy(out, in, desc_size);
367 out = (void *)out + desc_size;