arm-stub.c 12.2 KB
Newer Older
M
Mark Salter 已提交
1 2 3 4 5 6 7 8 9 10 11 12 13 14
/*
 * 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.
 *
 */

15
#include <linux/efi.h>
16
#include <linux/sort.h>
17 18 19 20
#include <asm/efi.h>

#include "efistub.h"

21 22
bool __nokaslr;

23
static int efi_get_secureboot(efi_system_table_t *sys_table_arg)
24
{
25
	static efi_char16_t const sb_var_name[] = {
26
		'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0 };
27 28
	static efi_char16_t const sm_var_name[] = {
		'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0 };
29

30
	efi_guid_t var_guid = EFI_GLOBAL_VARIABLE_GUID;
31 32
	efi_get_variable_t *f_getvar = sys_table_arg->runtime->get_variable;
	u8 val;
33 34
	unsigned long size = sizeof(val);
	efi_status_t status;
35

36
	status = f_getvar((efi_char16_t *)sb_var_name, (efi_guid_t *)&var_guid,
37 38
			  NULL, &size, &val);

39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56
	if (status != EFI_SUCCESS)
		goto out_efi_err;

	if (val == 0)
		return 0;

	status = f_getvar((efi_char16_t *)sm_var_name, (efi_guid_t *)&var_guid,
			  NULL, &size, &val);

	if (status != EFI_SUCCESS)
		goto out_efi_err;

	if (val == 1)
		return 0;

	return 1;

out_efi_err:
57 58 59
	switch (status) {
	case EFI_NOT_FOUND:
		return 0;
60 61 62 63
	case EFI_DEVICE_ERROR:
		return -EIO;
	case EFI_SECURITY_VIOLATION:
		return -EACCES;
64
	default:
65
		return -EINVAL;
66 67 68
	}
}

69 70
efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
			     void *__image, void **__fh)
M
Mark Salter 已提交
71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92
{
	efi_file_io_interface_t *io;
	efi_loaded_image_t *image = __image;
	efi_file_handle_t *fh;
	efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
	efi_status_t status;
	void *handle = (void *)(unsigned long)image->device_handle;

	status = sys_table_arg->boottime->handle_protocol(handle,
				 &fs_proto, (void **)&io);
	if (status != EFI_SUCCESS) {
		efi_printk(sys_table_arg, "Failed to handle fs_proto\n");
		return status;
	}

	status = io->open_volume(io, &fh);
	if (status != EFI_SUCCESS)
		efi_printk(sys_table_arg, "Failed to open volume\n");

	*__fh = fh;
	return status;
}
93 94

void efi_char16_printk(efi_system_table_t *sys_table_arg,
M
Mark Salter 已提交
95 96 97 98 99 100 101 102
			      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);
}

103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121
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;
}
M
Mark Salter 已提交
122 123 124 125 126 127 128

/*
 * 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.
 */
129 130 131 132 133 134 135
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);
M
Mark Salter 已提交
136 137 138 139 140 141
/*
 * 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.
 */
142
unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
M
Mark Salter 已提交
143 144 145 146 147 148 149 150 151
			       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;
152
	unsigned long fdt_addr = 0;  /* Original DTB */
153
	unsigned long fdt_size = 0;
M
Mark Salter 已提交
154 155 156 157 158 159
	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;
160
	int secure_boot = 0;
161
	struct screen_info *si;
M
Mark Salter 已提交
162 163 164 165 166 167 168

	/* Check if we were booted by the EFI firmware */
	if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
		goto fail;

	pr_efi(sys_table, "Booting Linux Kernel...\n");

169 170 171 172
	status = check_platform_features(sys_table);
	if (status != EFI_SUCCESS)
		goto fail;

M
Mark Salter 已提交
173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198
	/*
	 * 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");
199 200 201 202 203 204 205 206 207 208 209 210 211 212 213
		goto fail;
	}

	/* check whether 'nokaslr' was passed on the command line */
	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
		static const u8 default_cmdline[] = CONFIG_CMDLINE;
		const u8 *str, *cmdline = cmdline_ptr;

		if (IS_ENABLED(CONFIG_CMDLINE_FORCE))
			cmdline = default_cmdline;
		str = strstr(cmdline, "nokaslr");
		if (str == cmdline || (str > cmdline && *(str - 1) == ' '))
			__nokaslr = true;
	}

214 215
	si = setup_graphics(sys_table);

216 217 218 219 220 221 222
	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;
M
Mark Salter 已提交
223 224
	}

225 226 227 228
	status = efi_parse_options(cmdline_ptr);
	if (status != EFI_SUCCESS)
		pr_efi_err(sys_table, "Failed to parse EFI cmdline options\n");

229 230 231 232 233 234 235 236 237
	secure_boot = efi_get_secureboot(sys_table);
	if (secure_boot > 0)
		pr_efi(sys_table, "UEFI Secure Boot is enabled.\n");

	if (secure_boot < 0) {
		pr_efi_err(sys_table,
			"could not determine UEFI Secure Boot status.\n");
	}

238 239 240 241
	/*
	 * Unauthenticated device tree data is a security hazard, so
	 * ignore 'dtb=' unless UEFI Secure Boot is disabled.
	 */
242 243
	if (secure_boot != 0 && strstr(cmdline_ptr, "dtb=")) {
		pr_efi(sys_table, "Ignoring DTB from command line.\n");
244
	} else {
M
Mark Salter 已提交
245 246
		status = handle_cmdline_files(sys_table, image, cmdline_ptr,
					      "dtb=",
247
					      ~0UL, &fdt_addr, &fdt_size);
M
Mark Salter 已提交
248 249 250

		if (status != EFI_SUCCESS) {
			pr_efi_err(sys_table, "Failed to load device tree!\n");
251
			goto fail_free_image;
M
Mark Salter 已提交
252 253
		}
	}
254 255 256 257

	if (fdt_addr) {
		pr_efi(sys_table, "Using DTB from command line\n");
	} else {
258
		/* Look for a device tree configuration table entry. */
259
		fdt_addr = (uintptr_t)get_fdt(sys_table, &fdt_size);
260 261 262 263 264 265
		if (fdt_addr)
			pr_efi(sys_table, "Using DTB from configuration table\n");
	}

	if (!fdt_addr)
		pr_efi(sys_table, "Generating empty DTB\n");
M
Mark Salter 已提交
266 267 268 269 270 271 272 273

	status = handle_cmdline_files(sys_table, image, cmdline_ptr,
				      "initrd=", dram_base + SZ_512M,
				      (unsigned long *)&initrd_addr,
				      (unsigned long *)&initrd_size);
	if (status != EFI_SUCCESS)
		pr_efi_err(sys_table, "Failed initrd from command line!\n");

274 275
	efi_random_get_seed(sys_table);

M
Mark Salter 已提交
276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297
	new_fdt_addr = fdt_addr;
	status = allocate_new_fdt_and_exit_boot(sys_table, handle,
				&new_fdt_addr, dram_base + MAX_FDT_OFFSET,
				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);
298
fail_free_cmdline:
299
	free_screen_info(sys_table, si);
300
	efi_free(sys_table, cmdline_size, (unsigned long)cmdline_ptr);
M
Mark Salter 已提交
301 302 303
fail:
	return EFI_ERROR;
}
304 305 306 307 308 309 310 311

/*
 * 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.
R
Roy Franz 已提交
312 313
 * Since 32-bit ARM could potentially execute with a 1G/3G user/kernel split,
 * map everything below 1 GB.
314
 */
R
Roy Franz 已提交
315
#define EFI_RT_VIRTUAL_BASE	SZ_512M
316

317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354
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;
}

355 356 357 358 359 360 361 362 363 364 365 366
/*
 * 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 = EFI_RT_VIRTUAL_BASE;
367
	efi_memory_desc_t *in, *prev = NULL, *out = runtime_map;
368 369
	int l;

370 371 372 373 374 375 376 377 378 379 380 381
	/*
	 * 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.
	 */
	sort(memory_map, map_size / desc_size, desc_size, cmp_mem_desc, NULL);

	for (l = 0; l < map_size; l += desc_size, prev = in) {
382 383
		u64 paddr, size;

384
		in = (void *)memory_map + l;
385 386 387
		if (!(in->attribute & EFI_MEMORY_RUNTIME))
			continue;

388 389 390
		paddr = in->phys_addr;
		size = in->num_pages * EFI_PAGE_SIZE;

391 392 393 394 395
		/*
		 * Make the mapping compatible with 64k pages: this allows
		 * a 4k page size kernel to kexec a 64k page size kernel and
		 * vice versa.
		 */
396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412
		if (!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);
		}
413 414 415 416 417 418 419 420 421

		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;
	}
}