forked from Minki/linux
dca0f971ea
Drivers need a way to access the EFI memory map at runtime. ARM and arm64 currently provide this by remapping the EFI memory map into the vmalloc space before setting up the EFI virtual mappings. x86 does not provide this functionality which has resulted in the code in efi_mem_desc_lookup() where it will manually map individual EFI memmap entries if the memmap has already been torn down on x86, /* * If a driver calls this after efi_free_boot_services, * ->map will be NULL, and the target may also not be mapped. * So just always get our own virtual map on the CPU. * */ md = early_memremap(p, sizeof (*md)); There isn't a good reason for not providing a permanent EFI memory map for runtime queries, especially since the EFI regions are not mapped into the standard kernel page tables. Tested-by: Dave Young <dyoung@redhat.com> [kexec/kdump] Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> [arm] Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Leif Lindholm <leif.lindholm@linaro.org> Cc: Peter Jones <pjones@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
148 lines
3.4 KiB
C
148 lines
3.4 KiB
C
/*
|
|
* Extensible Firmware Interface
|
|
*
|
|
* Based on Extensible Firmware Interface Specification version 2.4
|
|
*
|
|
* Copyright (C) 2013, 2014 Linaro Ltd.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
*/
|
|
|
|
#include <linux/efi.h>
|
|
#include <linux/io.h>
|
|
#include <linux/memblock.h>
|
|
#include <linux/mm_types.h>
|
|
#include <linux/preempt.h>
|
|
#include <linux/rbtree.h>
|
|
#include <linux/rwsem.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/spinlock.h>
|
|
|
|
#include <asm/cacheflush.h>
|
|
#include <asm/efi.h>
|
|
#include <asm/mmu.h>
|
|
#include <asm/pgalloc.h>
|
|
#include <asm/pgtable.h>
|
|
|
|
extern u64 efi_system_table;
|
|
|
|
static struct mm_struct efi_mm = {
|
|
.mm_rb = RB_ROOT,
|
|
.mm_users = ATOMIC_INIT(2),
|
|
.mm_count = ATOMIC_INIT(1),
|
|
.mmap_sem = __RWSEM_INITIALIZER(efi_mm.mmap_sem),
|
|
.page_table_lock = __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock),
|
|
.mmlist = LIST_HEAD_INIT(efi_mm.mmlist),
|
|
};
|
|
|
|
static bool __init efi_virtmap_init(void)
|
|
{
|
|
efi_memory_desc_t *md;
|
|
bool systab_found;
|
|
|
|
efi_mm.pgd = pgd_alloc(&efi_mm);
|
|
init_new_context(NULL, &efi_mm);
|
|
|
|
systab_found = false;
|
|
for_each_efi_memory_desc(md) {
|
|
phys_addr_t phys = md->phys_addr;
|
|
int ret;
|
|
|
|
if (!(md->attribute & EFI_MEMORY_RUNTIME))
|
|
continue;
|
|
if (md->virt_addr == 0)
|
|
return false;
|
|
|
|
ret = efi_create_mapping(&efi_mm, md);
|
|
if (!ret) {
|
|
pr_info(" EFI remap %pa => %p\n",
|
|
&phys, (void *)(unsigned long)md->virt_addr);
|
|
} else {
|
|
pr_warn(" EFI remap %pa: failed to create mapping (%d)\n",
|
|
&phys, ret);
|
|
return false;
|
|
}
|
|
/*
|
|
* If this entry covers the address of the UEFI system table,
|
|
* calculate and record its virtual address.
|
|
*/
|
|
if (efi_system_table >= phys &&
|
|
efi_system_table < phys + (md->num_pages * EFI_PAGE_SIZE)) {
|
|
efi.systab = (void *)(unsigned long)(efi_system_table -
|
|
phys + md->virt_addr);
|
|
systab_found = true;
|
|
}
|
|
}
|
|
if (!systab_found) {
|
|
pr_err("No virtual mapping found for the UEFI System Table\n");
|
|
return false;
|
|
}
|
|
|
|
if (efi_memattr_apply_permissions(&efi_mm, efi_set_mapping_permissions))
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,
|
|
* non-early mapping of the UEFI system table and virtual mappings for all
|
|
* EFI_MEMORY_RUNTIME regions.
|
|
*/
|
|
static int __init arm_enable_runtime_services(void)
|
|
{
|
|
u64 mapsize;
|
|
|
|
if (!efi_enabled(EFI_BOOT)) {
|
|
pr_info("EFI services will not be available.\n");
|
|
return 0;
|
|
}
|
|
|
|
if (efi_runtime_disabled()) {
|
|
pr_info("EFI runtime services will be disabled.\n");
|
|
return 0;
|
|
}
|
|
|
|
if (efi_enabled(EFI_RUNTIME_SERVICES)) {
|
|
pr_info("EFI runtime services access via paravirt.\n");
|
|
return 0;
|
|
}
|
|
|
|
pr_info("Remapping and enabling EFI services.\n");
|
|
|
|
mapsize = efi.memmap.desc_size * efi.memmap.nr_map;
|
|
|
|
if (efi_memmap_init_late(efi.memmap.phys_map, mapsize)) {
|
|
pr_err("Failed to remap EFI memory map\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
if (!efi_virtmap_init()) {
|
|
pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/* Set up runtime services function pointers */
|
|
efi_native_runtime_setup();
|
|
set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
|
|
|
|
return 0;
|
|
}
|
|
early_initcall(arm_enable_runtime_services);
|
|
|
|
void efi_virtmap_load(void)
|
|
{
|
|
preempt_disable();
|
|
efi_set_pgd(&efi_mm);
|
|
}
|
|
|
|
void efi_virtmap_unload(void)
|
|
{
|
|
efi_set_pgd(current->active_mm);
|
|
preempt_enable();
|
|
}
|