2 * Common EFI (Extensible Firmware Interface) support functions
3 * Based on Extensible Firmware Interface Specification version 1.0
5 * Copyright (C) 1999 VA Linux Systems
6 * Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
7 * Copyright (C) 1999-2002 Hewlett-Packard Co.
8 * David Mosberger-Tang <davidm@hpl.hp.com>
9 * Stephane Eranian <eranian@hpl.hp.com>
10 * Copyright (C) 2005-2008 Intel Co.
11 * Fenghua Yu <fenghua.yu@intel.com>
12 * Bibo Mao <bibo.mao@intel.com>
13 * Chandramouli Narayanan <mouli@linux.intel.com>
14 * Huang Ying <ying.huang@intel.com>
15 * Copyright (C) 2013 SuSE Labs
16 * Borislav Petkov <bp@suse.de> - runtime services VA mapping
18 * Copied from efi_32.c to eliminate the duplicated code between EFI
19 * 32/64 support code. --ying 2007-10-26
21 * All EFI Runtime Services are not implemented yet as EFI only
22 * supports physical mode addressing on SoftSDV. This is to be fixed
23 * in a future version. --drummond 1999-07-20
25 * Implemented EFI runtime services and virtual mode calls. --davidm
27 * Goutham Rao: <goutham.rao@intel.com>
28 * Skip non-WB memory and ignore empty memory ranges.
31 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
33 #include <linux/kernel.h>
34 #include <linux/init.h>
35 #include <linux/efi.h>
36 #include <linux/efi-bgrt.h>
37 #include <linux/export.h>
38 #include <linux/bootmem.h>
39 #include <linux/slab.h>
40 #include <linux/memblock.h>
41 #include <linux/spinlock.h>
42 #include <linux/uaccess.h>
43 #include <linux/time.h>
45 #include <linux/reboot.h>
46 #include <linux/bcd.h>
48 #include <asm/setup.h>
51 #include <asm/cacheflush.h>
52 #include <asm/tlbflush.h>
53 #include <asm/x86_init.h>
55 #include <asm/uv/uv.h>
59 struct efi_memory_map memmap
;
61 static struct efi efi_phys __initdata
;
62 static efi_system_table_t efi_systab __initdata
;
64 static efi_config_table_type_t arch_tables
[] __initdata
= {
66 {UV_SYSTEM_TABLE_GUID
, "UVsystab", &efi
.uv_systab
},
68 {NULL_GUID
, NULL
, NULL
},
71 u64 efi_setup
; /* efi setup_data physical address */
74 EXPORT_SYMBOL(add_efi_memmap
);
76 static int __init
setup_add_efi_memmap(char *arg
)
81 early_param("add_efi_memmap", setup_add_efi_memmap
);
83 static efi_status_t __init
phys_efi_set_virtual_address_map(
84 unsigned long memory_map_size
,
85 unsigned long descriptor_size
,
86 u32 descriptor_version
,
87 efi_memory_desc_t
*virtual_map
)
91 efi_call_phys_prelog();
92 status
= efi_call_phys(efi_phys
.set_virtual_address_map
,
93 memory_map_size
, descriptor_size
,
94 descriptor_version
, virtual_map
);
95 efi_call_phys_epilog();
99 void efi_get_time(struct timespec
*now
)
105 status
= efi
.get_time(&eft
, &cap
);
106 if (status
!= EFI_SUCCESS
)
107 pr_err("Oops: efitime: can't read time!\n");
109 now
->tv_sec
= mktime(eft
.year
, eft
.month
, eft
.day
, eft
.hour
,
110 eft
.minute
, eft
.second
);
115 * Tell the kernel about the EFI memory map. This might include
116 * more than the max 128 entries that can fit in the e820 legacy
117 * (zeropage) memory map.
120 static void __init
do_add_efi_memmap(void)
124 for (p
= memmap
.map
; p
< memmap
.map_end
; p
+= memmap
.desc_size
) {
125 efi_memory_desc_t
*md
= p
;
126 unsigned long long start
= md
->phys_addr
;
127 unsigned long long size
= md
->num_pages
<< EFI_PAGE_SHIFT
;
131 case EFI_LOADER_CODE
:
132 case EFI_LOADER_DATA
:
133 case EFI_BOOT_SERVICES_CODE
:
134 case EFI_BOOT_SERVICES_DATA
:
135 case EFI_CONVENTIONAL_MEMORY
:
136 if (md
->attribute
& EFI_MEMORY_WB
)
137 e820_type
= E820_RAM
;
139 e820_type
= E820_RESERVED
;
141 case EFI_ACPI_RECLAIM_MEMORY
:
142 e820_type
= E820_ACPI
;
144 case EFI_ACPI_MEMORY_NVS
:
145 e820_type
= E820_NVS
;
147 case EFI_UNUSABLE_MEMORY
:
148 e820_type
= E820_UNUSABLE
;
152 * EFI_RESERVED_TYPE EFI_RUNTIME_SERVICES_CODE
153 * EFI_RUNTIME_SERVICES_DATA EFI_MEMORY_MAPPED_IO
154 * EFI_MEMORY_MAPPED_IO_PORT_SPACE EFI_PAL_CODE
156 e820_type
= E820_RESERVED
;
159 e820_add_region(start
, size
, e820_type
);
161 sanitize_e820_map(e820
.map
, ARRAY_SIZE(e820
.map
), &e820
.nr_map
);
164 int __init
efi_memblock_x86_reserve_range(void)
166 struct efi_info
*e
= &boot_params
.efi_info
;
169 if (efi_enabled(EFI_PARAVIRT
))
173 /* Can't handle data above 4GB at this time */
174 if (e
->efi_memmap_hi
) {
175 pr_err("Memory map is above 4GB, disabling EFI.\n");
178 pmap
= e
->efi_memmap
;
180 pmap
= (e
->efi_memmap
| ((__u64
)e
->efi_memmap_hi
<< 32));
182 memmap
.phys_map
= (void *)pmap
;
183 memmap
.nr_map
= e
->efi_memmap_size
/
185 memmap
.desc_size
= e
->efi_memdesc_size
;
186 memmap
.desc_version
= e
->efi_memdesc_version
;
188 memblock_reserve(pmap
, memmap
.nr_map
* memmap
.desc_size
);
190 efi
.memmap
= &memmap
;
195 static void __init
print_efi_memmap(void)
198 efi_memory_desc_t
*md
;
202 for (p
= memmap
.map
, i
= 0;
204 p
+= memmap
.desc_size
, i
++) {
206 pr_info("mem%02u: type=%u, attr=0x%llx, range=[0x%016llx-0x%016llx) (%lluMB)\n",
207 i
, md
->type
, md
->attribute
, md
->phys_addr
,
208 md
->phys_addr
+ (md
->num_pages
<< EFI_PAGE_SHIFT
),
209 (md
->num_pages
>> (20 - EFI_PAGE_SHIFT
)));
211 #endif /* EFI_DEBUG */
214 void __init
efi_unmap_memmap(void)
216 clear_bit(EFI_MEMMAP
, &efi
.flags
);
218 early_memunmap(memmap
.map
, memmap
.nr_map
* memmap
.desc_size
);
223 static int __init
efi_systab_init(void *phys
)
225 if (efi_enabled(EFI_64BIT
)) {
226 efi_system_table_64_t
*systab64
;
227 struct efi_setup_data
*data
= NULL
;
231 data
= early_memremap(efi_setup
, sizeof(*data
));
235 systab64
= early_memremap((unsigned long)phys
,
237 if (systab64
== NULL
) {
238 pr_err("Couldn't map the system table!\n");
240 early_memunmap(data
, sizeof(*data
));
244 efi_systab
.hdr
= systab64
->hdr
;
245 efi_systab
.fw_vendor
= data
? (unsigned long)data
->fw_vendor
:
247 tmp
|= data
? data
->fw_vendor
: systab64
->fw_vendor
;
248 efi_systab
.fw_revision
= systab64
->fw_revision
;
249 efi_systab
.con_in_handle
= systab64
->con_in_handle
;
250 tmp
|= systab64
->con_in_handle
;
251 efi_systab
.con_in
= systab64
->con_in
;
252 tmp
|= systab64
->con_in
;
253 efi_systab
.con_out_handle
= systab64
->con_out_handle
;
254 tmp
|= systab64
->con_out_handle
;
255 efi_systab
.con_out
= systab64
->con_out
;
256 tmp
|= systab64
->con_out
;
257 efi_systab
.stderr_handle
= systab64
->stderr_handle
;
258 tmp
|= systab64
->stderr_handle
;
259 efi_systab
.stderr
= systab64
->stderr
;
260 tmp
|= systab64
->stderr
;
261 efi_systab
.runtime
= data
?
262 (void *)(unsigned long)data
->runtime
:
263 (void *)(unsigned long)systab64
->runtime
;
264 tmp
|= data
? data
->runtime
: systab64
->runtime
;
265 efi_systab
.boottime
= (void *)(unsigned long)systab64
->boottime
;
266 tmp
|= systab64
->boottime
;
267 efi_systab
.nr_tables
= systab64
->nr_tables
;
268 efi_systab
.tables
= data
? (unsigned long)data
->tables
:
270 tmp
|= data
? data
->tables
: systab64
->tables
;
272 early_memunmap(systab64
, sizeof(*systab64
));
274 early_memunmap(data
, sizeof(*data
));
277 pr_err("EFI data located above 4GB, disabling EFI.\n");
282 efi_system_table_32_t
*systab32
;
284 systab32
= early_memremap((unsigned long)phys
,
286 if (systab32
== NULL
) {
287 pr_err("Couldn't map the system table!\n");
291 efi_systab
.hdr
= systab32
->hdr
;
292 efi_systab
.fw_vendor
= systab32
->fw_vendor
;
293 efi_systab
.fw_revision
= systab32
->fw_revision
;
294 efi_systab
.con_in_handle
= systab32
->con_in_handle
;
295 efi_systab
.con_in
= systab32
->con_in
;
296 efi_systab
.con_out_handle
= systab32
->con_out_handle
;
297 efi_systab
.con_out
= systab32
->con_out
;
298 efi_systab
.stderr_handle
= systab32
->stderr_handle
;
299 efi_systab
.stderr
= systab32
->stderr
;
300 efi_systab
.runtime
= (void *)(unsigned long)systab32
->runtime
;
301 efi_systab
.boottime
= (void *)(unsigned long)systab32
->boottime
;
302 efi_systab
.nr_tables
= systab32
->nr_tables
;
303 efi_systab
.tables
= systab32
->tables
;
305 early_memunmap(systab32
, sizeof(*systab32
));
308 efi
.systab
= &efi_systab
;
311 * Verify the EFI Table
313 if (efi
.systab
->hdr
.signature
!= EFI_SYSTEM_TABLE_SIGNATURE
) {
314 pr_err("System table signature incorrect!\n");
317 if ((efi
.systab
->hdr
.revision
>> 16) == 0)
318 pr_err("Warning: System table version %d.%02d, expected 1.00 or greater!\n",
319 efi
.systab
->hdr
.revision
>> 16,
320 efi
.systab
->hdr
.revision
& 0xffff);
322 set_bit(EFI_SYSTEM_TABLES
, &efi
.flags
);
327 static int __init
efi_runtime_init32(void)
329 efi_runtime_services_32_t
*runtime
;
331 runtime
= early_memremap((unsigned long)efi
.systab
->runtime
,
332 sizeof(efi_runtime_services_32_t
));
334 pr_err("Could not map the runtime service table!\n");
339 * We will only need *early* access to the following two
340 * EFI runtime services before set_virtual_address_map
343 efi_phys
.set_virtual_address_map
=
344 (efi_set_virtual_address_map_t
*)
345 (unsigned long)runtime
->set_virtual_address_map
;
346 early_memunmap(runtime
, sizeof(efi_runtime_services_32_t
));
351 static int __init
efi_runtime_init64(void)
353 efi_runtime_services_64_t
*runtime
;
355 runtime
= early_memremap((unsigned long)efi
.systab
->runtime
,
356 sizeof(efi_runtime_services_64_t
));
358 pr_err("Could not map the runtime service table!\n");
363 * We will only need *early* access to the following two
364 * EFI runtime services before set_virtual_address_map
367 efi_phys
.set_virtual_address_map
=
368 (efi_set_virtual_address_map_t
*)
369 (unsigned long)runtime
->set_virtual_address_map
;
370 early_memunmap(runtime
, sizeof(efi_runtime_services_64_t
));
375 static int __init
efi_runtime_init(void)
380 * Check out the runtime services table. We need to map
381 * the runtime services table so that we can grab the physical
382 * address of several of the EFI runtime functions, needed to
383 * set the firmware into virtual mode.
385 * When EFI_PARAVIRT is in force then we could not map runtime
386 * service memory region because we do not have direct access to it.
387 * However, runtime services are available through proxy functions
388 * (e.g. in case of Xen dom0 EFI implementation they call special
389 * hypercall which executes relevant EFI functions) and that is why
390 * they are always enabled.
393 if (!efi_enabled(EFI_PARAVIRT
)) {
394 if (efi_enabled(EFI_64BIT
))
395 rv
= efi_runtime_init64();
397 rv
= efi_runtime_init32();
403 set_bit(EFI_RUNTIME_SERVICES
, &efi
.flags
);
408 static int __init
efi_memmap_init(void)
410 if (efi_enabled(EFI_PARAVIRT
))
413 /* Map the EFI memory map */
414 memmap
.map
= early_memremap((unsigned long)memmap
.phys_map
,
415 memmap
.nr_map
* memmap
.desc_size
);
416 if (memmap
.map
== NULL
) {
417 pr_err("Could not map the memory map!\n");
420 memmap
.map_end
= memmap
.map
+ (memmap
.nr_map
* memmap
.desc_size
);
425 set_bit(EFI_MEMMAP
, &efi
.flags
);
430 void __init
efi_init(void)
433 char vendor
[100] = "unknown";
438 if (boot_params
.efi_info
.efi_systab_hi
||
439 boot_params
.efi_info
.efi_memmap_hi
) {
440 pr_info("Table located above 4GB, disabling EFI.\n");
443 efi_phys
.systab
= (efi_system_table_t
*)boot_params
.efi_info
.efi_systab
;
445 efi_phys
.systab
= (efi_system_table_t
*)
446 (boot_params
.efi_info
.efi_systab
|
447 ((__u64
)boot_params
.efi_info
.efi_systab_hi
<<32));
450 if (efi_systab_init(efi_phys
.systab
))
453 efi
.config_table
= (unsigned long)efi
.systab
->tables
;
454 efi
.fw_vendor
= (unsigned long)efi
.systab
->fw_vendor
;
455 efi
.runtime
= (unsigned long)efi
.systab
->runtime
;
458 * Show what we know for posterity
460 c16
= tmp
= early_memremap(efi
.systab
->fw_vendor
, 2);
462 for (i
= 0; i
< sizeof(vendor
) - 1 && *c16
; ++i
)
466 pr_err("Could not map the firmware vendor!\n");
467 early_memunmap(tmp
, 2);
469 pr_info("EFI v%u.%.02u by %s\n",
470 efi
.systab
->hdr
.revision
>> 16,
471 efi
.systab
->hdr
.revision
& 0xffff, vendor
);
473 if (efi_reuse_config(efi
.systab
->tables
, efi
.systab
->nr_tables
))
476 if (efi_config_init(arch_tables
))
480 * Note: We currently don't support runtime services on an EFI
481 * that doesn't match the kernel 32/64-bit mode.
484 if (!efi_runtime_supported())
485 pr_info("No EFI runtime due to 32/64-bit mismatch with kernel\n");
487 if (efi_runtime_disabled() || efi_runtime_init())
490 if (efi_memmap_init())
496 void __init
efi_late_init(void)
501 void __init
efi_set_executable(efi_memory_desc_t
*md
, bool executable
)
505 addr
= md
->virt_addr
;
506 npages
= md
->num_pages
;
508 memrange_efi_to_native(&addr
, &npages
);
511 set_memory_x(addr
, npages
);
513 set_memory_nx(addr
, npages
);
516 void __init
runtime_code_page_mkexec(void)
518 efi_memory_desc_t
*md
;
521 /* Make EFI runtime service code area executable */
522 for (p
= memmap
.map
; p
< memmap
.map_end
; p
+= memmap
.desc_size
) {
525 if (md
->type
!= EFI_RUNTIME_SERVICES_CODE
)
528 efi_set_executable(md
, true);
532 void efi_memory_uc(u64 addr
, unsigned long size
)
534 unsigned long page_shift
= 1UL << EFI_PAGE_SHIFT
;
537 npages
= round_up(size
, page_shift
) / page_shift
;
538 memrange_efi_to_native(&addr
, &npages
);
539 set_memory_uc(addr
, npages
);
542 void __init
old_map_region(efi_memory_desc_t
*md
)
544 u64 start_pfn
, end_pfn
, end
;
548 start_pfn
= PFN_DOWN(md
->phys_addr
);
549 size
= md
->num_pages
<< PAGE_SHIFT
;
550 end
= md
->phys_addr
+ size
;
551 end_pfn
= PFN_UP(end
);
553 if (pfn_range_is_mapped(start_pfn
, end_pfn
)) {
554 va
= __va(md
->phys_addr
);
556 if (!(md
->attribute
& EFI_MEMORY_WB
))
557 efi_memory_uc((u64
)(unsigned long)va
, size
);
559 va
= efi_ioremap(md
->phys_addr
, size
,
560 md
->type
, md
->attribute
);
562 md
->virt_addr
= (u64
) (unsigned long) va
;
564 pr_err("ioremap of 0x%llX failed!\n",
565 (unsigned long long)md
->phys_addr
);
568 /* Merge contiguous regions of the same type and attribute */
569 static void __init
efi_merge_regions(void)
572 efi_memory_desc_t
*md
, *prev_md
= NULL
;
574 for (p
= memmap
.map
; p
< memmap
.map_end
; p
+= memmap
.desc_size
) {
583 if (prev_md
->type
!= md
->type
||
584 prev_md
->attribute
!= md
->attribute
) {
589 prev_size
= prev_md
->num_pages
<< EFI_PAGE_SHIFT
;
591 if (md
->phys_addr
== (prev_md
->phys_addr
+ prev_size
)) {
592 prev_md
->num_pages
+= md
->num_pages
;
593 md
->type
= EFI_RESERVED_TYPE
;
601 static void __init
get_systab_virt_addr(efi_memory_desc_t
*md
)
606 size
= md
->num_pages
<< EFI_PAGE_SHIFT
;
607 end
= md
->phys_addr
+ size
;
608 systab
= (u64
)(unsigned long)efi_phys
.systab
;
609 if (md
->phys_addr
<= systab
&& systab
< end
) {
610 systab
+= md
->virt_addr
- md
->phys_addr
;
611 efi
.systab
= (efi_system_table_t
*)(unsigned long)systab
;
615 static void __init
save_runtime_map(void)
618 efi_memory_desc_t
*md
;
619 void *tmp
, *p
, *q
= NULL
;
622 if (efi_enabled(EFI_OLD_MEMMAP
))
625 for (p
= memmap
.map
; p
< memmap
.map_end
; p
+= memmap
.desc_size
) {
628 if (!(md
->attribute
& EFI_MEMORY_RUNTIME
) ||
629 (md
->type
== EFI_BOOT_SERVICES_CODE
) ||
630 (md
->type
== EFI_BOOT_SERVICES_DATA
))
632 tmp
= krealloc(q
, (count
+ 1) * memmap
.desc_size
, GFP_KERNEL
);
637 memcpy(q
+ count
* memmap
.desc_size
, md
, memmap
.desc_size
);
641 efi_runtime_map_setup(q
, count
, memmap
.desc_size
);
646 pr_err("Error saving runtime map, efi runtime on kexec non-functional!!\n");
650 static void *realloc_pages(void *old_memmap
, int old_shift
)
654 ret
= (void *)__get_free_pages(GFP_KERNEL
, old_shift
+ 1);
659 * A first-time allocation doesn't have anything to copy.
664 memcpy(ret
, old_memmap
, PAGE_SIZE
<< old_shift
);
667 free_pages((unsigned long)old_memmap
, old_shift
);
672 * Map the efi memory ranges of the runtime services and update new_mmap with
675 static void * __init
efi_map_regions(int *count
, int *pg_shift
)
677 void *p
, *new_memmap
= NULL
;
678 unsigned long left
= 0;
679 efi_memory_desc_t
*md
;
681 for (p
= memmap
.map
; p
< memmap
.map_end
; p
+= memmap
.desc_size
) {
683 if (!(md
->attribute
& EFI_MEMORY_RUNTIME
)) {
685 if (md
->type
!= EFI_BOOT_SERVICES_CODE
&&
686 md
->type
!= EFI_BOOT_SERVICES_DATA
)
692 get_systab_virt_addr(md
);
694 if (left
< memmap
.desc_size
) {
695 new_memmap
= realloc_pages(new_memmap
, *pg_shift
);
699 left
+= PAGE_SIZE
<< *pg_shift
;
703 memcpy(new_memmap
+ (*count
* memmap
.desc_size
), md
,
706 left
-= memmap
.desc_size
;
713 static void __init
kexec_enter_virtual_mode(void)
716 efi_memory_desc_t
*md
;
722 * We don't do virtual mode, since we don't do runtime services, on
725 if (!efi_is_native()) {
731 * Map efi regions which were passed via setup_data. The virt_addr is a
732 * fixed addr which was used in first kernel of a kexec boot.
734 for (p
= memmap
.map
; p
< memmap
.map_end
; p
+= memmap
.desc_size
) {
736 efi_map_region_fixed(md
); /* FIXME: add error handling */
737 get_systab_virt_addr(md
);
744 efi_sync_low_kernel_mappings();
747 * Now that EFI is in virtual mode, update the function
748 * pointers in the runtime service table to the new virtual addresses.
750 * Call EFI services through wrapper functions.
752 efi
.runtime_version
= efi_systab
.hdr
.revision
;
754 efi_native_runtime_setup();
756 efi
.set_virtual_address_map
= NULL
;
758 if (efi_enabled(EFI_OLD_MEMMAP
) && (__supported_pte_mask
& _PAGE_NX
))
759 runtime_code_page_mkexec();
761 /* clean DUMMY object */
762 efi_delete_dummy_variable();
767 * This function will switch the EFI runtime services to virtual mode.
768 * Essentially, we look through the EFI memmap and map every region that
769 * has the runtime attribute bit set in its memory descriptor into the
770 * ->trampoline_pgd page table using a top-down VA allocation scheme.
772 * The old method which used to update that memory descriptor with the
773 * virtual address obtained from ioremap() is still supported when the
774 * kernel is booted with efi=old_map on its command line. Same old
775 * method enabled the runtime services to be called without having to
776 * thunk back into physical mode for every invocation.
778 * The new method does a pagetable switch in a preemption-safe manner
779 * so that we're in a different address space when calling a runtime
780 * function. For function arguments passing we do copy the PGDs of the
781 * kernel page table into ->trampoline_pgd prior to each call.
783 * Specially for kexec boot, efi runtime maps in previous kernel should
784 * be passed in via setup_data. In that case runtime ranges will be mapped
785 * to the same virtual addresses as the first kernel, see
786 * kexec_enter_virtual_mode().
788 static void __init
__efi_enter_virtual_mode(void)
790 int count
= 0, pg_shift
= 0;
791 void *new_memmap
= NULL
;
797 new_memmap
= efi_map_regions(&count
, &pg_shift
);
799 pr_err("Error reallocating memory, EFI runtime non-functional!\n");
807 if (efi_setup_page_tables(__pa(new_memmap
), 1 << pg_shift
))
810 efi_sync_low_kernel_mappings();
811 efi_dump_pagetable();
813 if (efi_is_native()) {
814 status
= phys_efi_set_virtual_address_map(
815 memmap
.desc_size
* count
,
818 (efi_memory_desc_t
*)__pa(new_memmap
));
820 status
= efi_thunk_set_virtual_address_map(
821 efi_phys
.set_virtual_address_map
,
822 memmap
.desc_size
* count
,
825 (efi_memory_desc_t
*)__pa(new_memmap
));
828 if (status
!= EFI_SUCCESS
) {
829 pr_alert("Unable to switch EFI into virtual mode (status=%lx)!\n",
831 panic("EFI call to SetVirtualAddressMap() failed!");
835 * Now that EFI is in virtual mode, update the function
836 * pointers in the runtime service table to the new virtual addresses.
838 * Call EFI services through wrapper functions.
840 efi
.runtime_version
= efi_systab
.hdr
.revision
;
843 efi_native_runtime_setup();
845 efi_thunk_runtime_setup();
847 efi
.set_virtual_address_map
= NULL
;
849 efi_runtime_mkexec();
852 * We mapped the descriptor array into the EFI pagetable above but we're
853 * not unmapping it here. Here's why:
855 * We're copying select PGDs from the kernel page table to the EFI page
856 * table and when we do so and make changes to those PGDs like unmapping
857 * stuff from them, those changes appear in the kernel page table and we
860 * From setup_real_mode():
863 * trampoline_pgd[0] = init_level4_pgt[pgd_index(__PAGE_OFFSET)].pgd;
865 * In this particular case, our allocation is in PGD 0 of the EFI page
866 * table but we've copied that PGD from PGD[272] of the EFI page table:
868 * pgd_index(__PAGE_OFFSET = 0xffff880000000000) = 272
870 * where the direct memory mapping in kernel space is.
872 * new_memmap's VA comes from that direct mapping and thus clearing it,
873 * it would get cleared in the kernel page table too.
875 * efi_cleanup_page_tables(__pa(new_memmap), 1 << pg_shift);
877 free_pages((unsigned long)new_memmap
, pg_shift
);
879 /* clean DUMMY object */
880 efi_delete_dummy_variable();
883 void __init
efi_enter_virtual_mode(void)
885 if (efi_enabled(EFI_PARAVIRT
))
889 kexec_enter_virtual_mode();
891 __efi_enter_virtual_mode();
895 * Convenience functions to obtain memory types and attributes
897 u32
efi_mem_type(unsigned long phys_addr
)
899 efi_memory_desc_t
*md
;
902 if (!efi_enabled(EFI_MEMMAP
))
905 for (p
= memmap
.map
; p
< memmap
.map_end
; p
+= memmap
.desc_size
) {
907 if ((md
->phys_addr
<= phys_addr
) &&
908 (phys_addr
< (md
->phys_addr
+
909 (md
->num_pages
<< EFI_PAGE_SHIFT
))))
915 u64
efi_mem_attributes(unsigned long phys_addr
)
917 efi_memory_desc_t
*md
;
920 if (!efi_enabled(EFI_MEMMAP
))
923 for (p
= memmap
.map
; p
< memmap
.map_end
; p
+= memmap
.desc_size
) {
925 if ((md
->phys_addr
<= phys_addr
) &&
926 (phys_addr
< (md
->phys_addr
+
927 (md
->num_pages
<< EFI_PAGE_SHIFT
))))
928 return md
->attribute
;
933 static int __init
arch_parse_efi_cmdline(char *str
)
935 if (parse_option_str(str
, "old_map"))
936 set_bit(EFI_OLD_MEMMAP
, &efi
.flags
);
940 early_param("efi", arch_parse_efi_cmdline
);