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// SPDX-License-Identifier: GPL-2.0
/*
* Extensible Firmware Interface
*
* Copyright (C) 2020 Western Digital Corporation or its affiliates.
*
* Based on Extensible Firmware Interface Specification version 2.4
* Adapted from drivers/firmware/efi/arm-runtime.c
*
*/
#include <linux/dmi.h>
#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 <linux/pgtable.h>
#include <asm/cacheflush.h>
#include <asm/efi.h>
#include <asm/mmu.h>
#include <asm/pgalloc.h>
static bool __init efi_virtmap_init(void)
{
efi_memory_desc_t *md;
efi_mm.pgd = pgd_alloc(&efi_mm);
mm_init_cpumask(&efi_mm);
init_new_context(NULL, &efi_mm);
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 == U64_MAX)
return false;
ret = efi_create_mapping(&efi_mm, md);
if (ret) {
pr_warn(" EFI remap %pa: failed to create mapping (%d)\n",
&phys, ret);
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 riscv_enable_runtime_services(void)
{
u64 mapsize;
if (!efi_enabled(EFI_BOOT)) {
pr_info("EFI services will not be available.\n");
return 0;
}
efi_memmap_unmap();
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 0;
}
if (efi_soft_reserve_enabled()) {
efi_memory_desc_t *md;
for_each_efi_memory_desc(md) {
u64 md_size = md->num_pages << EFI_PAGE_SHIFT;
struct resource *res;
if (!(md->attribute & EFI_MEMORY_SP))
continue;
res = kzalloc(sizeof(*res), GFP_KERNEL);
if (WARN_ON(!res))
break;
res->start = md->phys_addr;
res->end = md->phys_addr + md_size - 1;
res->name = "Soft Reserved";
res->flags = IORESOURCE_MEM;
res->desc = IORES_DESC_SOFT_RESERVED;
insert_resource(&iomem_resource, res);
}
}
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");
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(riscv_enable_runtime_services);
static void efi_virtmap_load(void)
{
preempt_disable();
switch_mm(current->active_mm, &efi_mm, NULL);
}
static void efi_virtmap_unload(void)
{
switch_mm(&efi_mm, current->active_mm, NULL);
preempt_enable();
}
void arch_efi_call_virt_setup(void)
{
sync_kernel_mappings(efi_mm.pgd);
efi_virtmap_load();
}
void arch_efi_call_virt_teardown(void)
{
efi_virtmap_unload();
}
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