1 #define pr_fmt(fmt) "efi: " fmt
3 #include <linux/init.h>
4 #include <linux/kernel.h>
5 #include <linux/string.h>
6 #include <linux/time.h>
7 #include <linux/types.h>
9 #include <linux/slab.h>
10 #include <linux/memblock.h>
11 #include <linux/bootmem.h>
12 #include <linux/acpi.h>
13 #include <linux/dmi.h>
15 #include <asm/e820/api.h>
17 #include <asm/uv/uv.h>
19 #define EFI_MIN_RESERVE 5120
21 #define EFI_DUMMY_GUID \
22 EFI_GUID(0x4424ac57, 0xbe4b, 0x47dd, 0x9e, 0x97, 0xed, 0x50, 0xf0, 0x9f, 0x92, 0xa9)
24 static efi_char16_t efi_dummy_name
[6] = { 'D', 'U', 'M', 'M', 'Y', 0 };
26 static bool efi_no_storage_paranoia
;
29 * Some firmware implementations refuse to boot if there's insufficient
30 * space in the variable store. The implementation of garbage collection
31 * in some FW versions causes stale (deleted) variables to take up space
32 * longer than intended and space is only freed once the store becomes
33 * almost completely full.
35 * Enabling this option disables the space checks in
36 * efi_query_variable_store() and forces garbage collection.
38 * Only enable this option if deleting EFI variables does not free up
39 * space in your variable store, e.g. if despite deleting variables
40 * you're unable to create new ones.
42 static int __init
setup_storage_paranoia(char *arg
)
44 efi_no_storage_paranoia
= true;
47 early_param("efi_no_storage_paranoia", setup_storage_paranoia
);
50 * Deleting the dummy variable which kicks off garbage collection
52 void efi_delete_dummy_variable(void)
54 efi
.set_variable(efi_dummy_name
, &EFI_DUMMY_GUID
,
55 EFI_VARIABLE_NON_VOLATILE
|
56 EFI_VARIABLE_BOOTSERVICE_ACCESS
|
57 EFI_VARIABLE_RUNTIME_ACCESS
,
62 * In the nonblocking case we do not attempt to perform garbage
63 * collection if we do not have enough free space. Rather, we do the
64 * bare minimum check and give up immediately if the available space
65 * is below EFI_MIN_RESERVE.
67 * This function is intended to be small and simple because it is
68 * invoked from crash handler paths.
71 query_variable_store_nonblocking(u32 attributes
, unsigned long size
)
74 u64 storage_size
, remaining_size
, max_size
;
76 status
= efi
.query_variable_info_nonblocking(attributes
, &storage_size
,
79 if (status
!= EFI_SUCCESS
)
82 if (remaining_size
- size
< EFI_MIN_RESERVE
)
83 return EFI_OUT_OF_RESOURCES
;
89 * Some firmware implementations refuse to boot if there's insufficient space
90 * in the variable store. Ensure that we never use more than a safe limit.
92 * Return EFI_SUCCESS if it is safe to write 'size' bytes to the variable
95 efi_status_t
efi_query_variable_store(u32 attributes
, unsigned long size
,
99 u64 storage_size
, remaining_size
, max_size
;
101 if (!(attributes
& EFI_VARIABLE_NON_VOLATILE
))
105 return query_variable_store_nonblocking(attributes
, size
);
107 status
= efi
.query_variable_info(attributes
, &storage_size
,
108 &remaining_size
, &max_size
);
109 if (status
!= EFI_SUCCESS
)
113 * We account for that by refusing the write if permitting it would
114 * reduce the available space to under 5KB. This figure was provided by
115 * Samsung, so should be safe.
117 if ((remaining_size
- size
< EFI_MIN_RESERVE
) &&
118 !efi_no_storage_paranoia
) {
121 * Triggering garbage collection may require that the firmware
122 * generate a real EFI_OUT_OF_RESOURCES error. We can force
123 * that by attempting to use more space than is available.
125 unsigned long dummy_size
= remaining_size
+ 1024;
126 void *dummy
= kzalloc(dummy_size
, GFP_ATOMIC
);
129 return EFI_OUT_OF_RESOURCES
;
131 status
= efi
.set_variable(efi_dummy_name
, &EFI_DUMMY_GUID
,
132 EFI_VARIABLE_NON_VOLATILE
|
133 EFI_VARIABLE_BOOTSERVICE_ACCESS
|
134 EFI_VARIABLE_RUNTIME_ACCESS
,
137 if (status
== EFI_SUCCESS
) {
139 * This should have failed, so if it didn't make sure
140 * that we delete it...
142 efi_delete_dummy_variable();
148 * The runtime code may now have triggered a garbage collection
149 * run, so check the variable info again
151 status
= efi
.query_variable_info(attributes
, &storage_size
,
152 &remaining_size
, &max_size
);
154 if (status
!= EFI_SUCCESS
)
158 * There still isn't enough room, so return an error
160 if (remaining_size
- size
< EFI_MIN_RESERVE
)
161 return EFI_OUT_OF_RESOURCES
;
166 EXPORT_SYMBOL_GPL(efi_query_variable_store
);
169 * The UEFI specification makes it clear that the operating system is
170 * free to do whatever it wants with boot services code after
171 * ExitBootServices() has been called. Ignoring this recommendation a
172 * significant bunch of EFI implementations continue calling into boot
173 * services code (SetVirtualAddressMap). In order to work around such
174 * buggy implementations we reserve boot services region during EFI
175 * init and make sure it stays executable. Then, after
176 * SetVirtualAddressMap(), it is discarded.
178 * However, some boot services regions contain data that is required
179 * by drivers, so we need to track which memory ranges can never be
180 * freed. This is done by tagging those regions with the
181 * EFI_MEMORY_RUNTIME attribute.
183 * Any driver that wants to mark a region as reserved must use
184 * efi_mem_reserve() which will insert a new EFI memory descriptor
185 * into efi.memmap (splitting existing regions if necessary) and tag
186 * it with EFI_MEMORY_RUNTIME.
188 void __init
efi_arch_mem_reserve(phys_addr_t addr
, u64 size
)
190 phys_addr_t new_phys
, new_size
;
191 struct efi_mem_range mr
;
192 efi_memory_desc_t md
;
196 if (efi_mem_desc_lookup(addr
, &md
)) {
197 pr_err("Failed to lookup EFI memory descriptor for %pa\n", &addr
);
201 if (addr
+ size
> md
.phys_addr
+ (md
.num_pages
<< EFI_PAGE_SHIFT
)) {
202 pr_err("Region spans EFI memory descriptors, %pa\n", &addr
);
206 /* No need to reserve regions that will never be freed. */
207 if (md
.attribute
& EFI_MEMORY_RUNTIME
)
210 size
+= addr
% EFI_PAGE_SIZE
;
211 size
= round_up(size
, EFI_PAGE_SIZE
);
212 addr
= round_down(addr
, EFI_PAGE_SIZE
);
214 mr
.range
.start
= addr
;
215 mr
.range
.end
= addr
+ size
- 1;
216 mr
.attribute
= md
.attribute
| EFI_MEMORY_RUNTIME
;
218 num_entries
= efi_memmap_split_count(&md
, &mr
.range
);
219 num_entries
+= efi
.memmap
.nr_map
;
221 new_size
= efi
.memmap
.desc_size
* num_entries
;
223 new_phys
= efi_memmap_alloc(num_entries
);
225 pr_err("Could not allocate boot services memmap\n");
229 new = early_memremap(new_phys
, new_size
);
231 pr_err("Failed to map new boot services memmap\n");
235 efi_memmap_insert(&efi
.memmap
, new, &mr
);
236 early_memunmap(new, new_size
);
238 efi_memmap_install(new_phys
, num_entries
);
242 * Helper function for efi_reserve_boot_services() to figure out if we
243 * can free regions in efi_free_boot_services().
245 * Use this function to ensure we do not free regions owned by somebody
246 * else. We must only reserve (and then free) regions:
248 * - Not within any part of the kernel
249 * - Not the BIOS reserved area (E820_TYPE_RESERVED, E820_TYPE_NVS, etc)
251 static bool can_free_region(u64 start
, u64 size
)
253 if (start
+ size
> __pa_symbol(_text
) && start
<= __pa_symbol(_end
))
256 if (!e820__mapped_all(start
, start
+size
, E820_TYPE_RAM
))
262 void __init
efi_reserve_boot_services(void)
264 efi_memory_desc_t
*md
;
266 for_each_efi_memory_desc(md
) {
267 u64 start
= md
->phys_addr
;
268 u64 size
= md
->num_pages
<< EFI_PAGE_SHIFT
;
269 bool already_reserved
;
271 if (md
->type
!= EFI_BOOT_SERVICES_CODE
&&
272 md
->type
!= EFI_BOOT_SERVICES_DATA
)
275 already_reserved
= memblock_is_region_reserved(start
, size
);
278 * Because the following memblock_reserve() is paired
279 * with free_bootmem_late() for this region in
280 * efi_free_boot_services(), we must be extremely
281 * careful not to reserve, and subsequently free,
282 * critical regions of memory (like the kernel image) or
283 * those regions that somebody else has already
286 * A good example of a critical region that must not be
287 * freed is page zero (first 4Kb of memory), which may
288 * contain boot services code/data but is marked
289 * E820_TYPE_RESERVED by trim_bios_range().
291 if (!already_reserved
) {
292 memblock_reserve(start
, size
);
295 * If we are the first to reserve the region, no
296 * one else cares about it. We own it and can
299 if (can_free_region(start
, size
))
304 * We don't own the region. We must not free it.
306 * Setting this bit for a boot services region really
307 * doesn't make sense as far as the firmware is
308 * concerned, but it does provide us with a way to tag
309 * those regions that must not be paired with
310 * free_bootmem_late().
312 md
->attribute
|= EFI_MEMORY_RUNTIME
;
316 void __init
efi_free_boot_services(void)
318 phys_addr_t new_phys
, new_size
;
319 efi_memory_desc_t
*md
;
323 for_each_efi_memory_desc(md
) {
324 unsigned long long start
= md
->phys_addr
;
325 unsigned long long size
= md
->num_pages
<< EFI_PAGE_SHIFT
;
328 if (md
->type
!= EFI_BOOT_SERVICES_CODE
&&
329 md
->type
!= EFI_BOOT_SERVICES_DATA
) {
334 /* Do not free, someone else owns it: */
335 if (md
->attribute
& EFI_MEMORY_RUNTIME
) {
341 * Nasty quirk: if all sub-1MB memory is used for boot
342 * services, we can get here without having allocated the
343 * real mode trampoline. It's too late to hand boot services
344 * memory back to the memblock allocator, so instead
345 * try to manually allocate the trampoline if needed.
347 * I've seen this on a Dell XPS 13 9350 with firmware
348 * 1.4.4 with SGX enabled booting Linux via Fedora 24's
349 * grub2-efi on a hard disk. (And no, I don't know why
350 * this happened, but Linux should still try to boot rather
353 rm_size
= real_mode_size_needed();
354 if (rm_size
&& (start
+ rm_size
) < (1<<20) && size
>= rm_size
) {
355 set_real_mode_mem(start
, rm_size
);
360 free_bootmem_late(start
, size
);
363 new_size
= efi
.memmap
.desc_size
* num_entries
;
364 new_phys
= efi_memmap_alloc(num_entries
);
366 pr_err("Failed to allocate new EFI memmap\n");
370 new = memremap(new_phys
, new_size
, MEMREMAP_WB
);
372 pr_err("Failed to map new EFI memmap\n");
377 * Build a new EFI memmap that excludes any boot services
378 * regions that are not tagged EFI_MEMORY_RUNTIME, since those
379 * regions have now been freed.
382 for_each_efi_memory_desc(md
) {
383 if (!(md
->attribute
& EFI_MEMORY_RUNTIME
) &&
384 (md
->type
== EFI_BOOT_SERVICES_CODE
||
385 md
->type
== EFI_BOOT_SERVICES_DATA
))
388 memcpy(new_md
, md
, efi
.memmap
.desc_size
);
389 new_md
+= efi
.memmap
.desc_size
;
394 if (efi_memmap_install(new_phys
, num_entries
)) {
395 pr_err("Could not install new EFI memmap\n");
401 * A number of config table entries get remapped to virtual addresses
402 * after entering EFI virtual mode. However, the kexec kernel requires
403 * their physical addresses therefore we pass them via setup_data and
404 * correct those entries to their respective physical addresses here.
406 * Currently only handles smbios which is necessary for some firmware
409 int __init
efi_reuse_config(u64 tables
, int nr_tables
)
413 struct efi_setup_data
*data
;
418 if (!efi_enabled(EFI_64BIT
))
421 data
= early_memremap(efi_setup
, sizeof(*data
));
430 sz
= sizeof(efi_config_table_64_t
);
432 p
= tablep
= early_memremap(tables
, nr_tables
* sz
);
434 pr_err("Could not map Configuration table!\n");
439 for (i
= 0; i
< efi
.systab
->nr_tables
; i
++) {
442 guid
= ((efi_config_table_64_t
*)p
)->guid
;
444 if (!efi_guidcmp(guid
, SMBIOS_TABLE_GUID
))
445 ((efi_config_table_64_t
*)p
)->table
= data
->smbios
;
448 early_memunmap(tablep
, nr_tables
* sz
);
451 early_memunmap(data
, sizeof(*data
));
456 static const struct dmi_system_id sgi_uv1_dmi
[] = {
458 { DMI_MATCH(DMI_PRODUCT_NAME
, "Stoutland Platform"),
459 DMI_MATCH(DMI_PRODUCT_VERSION
, "1.0"),
460 DMI_MATCH(DMI_BIOS_VENDOR
, "SGI.COM"),
463 { } /* NULL entry stops DMI scanning */
466 void __init
efi_apply_memmap_quirks(void)
469 * Once setup is done earlier, unmap the EFI memory map on mismatched
470 * firmware/kernel architectures since there is no support for runtime
473 if (!efi_runtime_supported()) {
474 pr_info("Setup done, disabling due to 32/64-bit mismatch\n");
478 /* UV2+ BIOS has a fix for this issue. UV1 still needs the quirk. */
479 if (dmi_check_system(sgi_uv1_dmi
))
480 set_bit(EFI_OLD_MEMMAP
, &efi
.flags
);
484 * For most modern platforms the preferred method of powering off is via
485 * ACPI. However, there are some that are known to require the use of
486 * EFI runtime services and for which ACPI does not work at all.
488 * Using EFI is a last resort, to be used only if no other option
491 bool efi_reboot_required(void)
493 if (!acpi_gbl_reduced_hardware
)
496 efi_reboot_quirk_mode
= EFI_RESET_WARM
;
500 bool efi_poweroff_required(void)
502 return acpi_gbl_reduced_hardware
|| acpi_no_s5
;