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1// SPDX-License-Identifier: GPL-2.02/*3 * Extensible Firmware Interface4 *5 * Copyright (C) 2020 Western Digital Corporation or its affiliates.6 *7 * Based on Extensible Firmware Interface Specification version 2.48 * Adapted from drivers/firmware/efi/arm-runtime.c9 *10 */11 12#include <linux/dmi.h>13#include <linux/efi.h>14#include <linux/io.h>15#include <linux/memblock.h>16#include <linux/mm_types.h>17#include <linux/preempt.h>18#include <linux/rbtree.h>19#include <linux/rwsem.h>20#include <linux/sched.h>21#include <linux/slab.h>22#include <linux/spinlock.h>23#include <linux/pgtable.h>24 25#include <asm/cacheflush.h>26#include <asm/efi.h>27#include <asm/mmu.h>28#include <asm/pgalloc.h>29 30static bool __init efi_virtmap_init(void)31{32 efi_memory_desc_t *md;33 34 efi_mm.pgd = pgd_alloc(&efi_mm);35 mm_init_cpumask(&efi_mm);36 init_new_context(NULL, &efi_mm);37 38 for_each_efi_memory_desc(md) {39 phys_addr_t phys = md->phys_addr;40 int ret;41 42 if (!(md->attribute & EFI_MEMORY_RUNTIME))43 continue;44 if (md->virt_addr == U64_MAX)45 return false;46 47 ret = efi_create_mapping(&efi_mm, md);48 if (ret) {49 pr_warn(" EFI remap %pa: failed to create mapping (%d)\n",50 &phys, ret);51 return false;52 }53 }54 55 if (efi_memattr_apply_permissions(&efi_mm, efi_set_mapping_permissions))56 return false;57 58 return true;59}60 61/*62 * Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,63 * non-early mapping of the UEFI system table and virtual mappings for all64 * EFI_MEMORY_RUNTIME regions.65 */66static int __init riscv_enable_runtime_services(void)67{68 u64 mapsize;69 70 if (!efi_enabled(EFI_BOOT)) {71 pr_info("EFI services will not be available.\n");72 return 0;73 }74 75 efi_memmap_unmap();76 77 mapsize = efi.memmap.desc_size * efi.memmap.nr_map;78 79 if (efi_memmap_init_late(efi.memmap.phys_map, mapsize)) {80 pr_err("Failed to remap EFI memory map\n");81 return 0;82 }83 84 if (efi_soft_reserve_enabled()) {85 efi_memory_desc_t *md;86 87 for_each_efi_memory_desc(md) {88 u64 md_size = md->num_pages << EFI_PAGE_SHIFT;89 struct resource *res;90 91 if (!(md->attribute & EFI_MEMORY_SP))92 continue;93 94 res = kzalloc(sizeof(*res), GFP_KERNEL);95 if (WARN_ON(!res))96 break;97 98 res->start = md->phys_addr;99 res->end = md->phys_addr + md_size - 1;100 res->name = "Soft Reserved";101 res->flags = IORESOURCE_MEM;102 res->desc = IORES_DESC_SOFT_RESERVED;103 104 insert_resource(&iomem_resource, res);105 }106 }107 108 if (efi_runtime_disabled()) {109 pr_info("EFI runtime services will be disabled.\n");110 return 0;111 }112 113 if (efi_enabled(EFI_RUNTIME_SERVICES)) {114 pr_info("EFI runtime services access via paravirt.\n");115 return 0;116 }117 118 pr_info("Remapping and enabling EFI services.\n");119 120 if (!efi_virtmap_init()) {121 pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n");122 return -ENOMEM;123 }124 125 /* Set up runtime services function pointers */126 efi_native_runtime_setup();127 set_bit(EFI_RUNTIME_SERVICES, &efi.flags);128 129 return 0;130}131early_initcall(riscv_enable_runtime_services);132 133static void efi_virtmap_load(void)134{135 preempt_disable();136 switch_mm(current->active_mm, &efi_mm, NULL);137}138 139static void efi_virtmap_unload(void)140{141 switch_mm(&efi_mm, current->active_mm, NULL);142 preempt_enable();143}144 145void arch_efi_call_virt_setup(void)146{147 sync_kernel_mappings(efi_mm.pgd);148 efi_virtmap_load();149}150 151void arch_efi_call_virt_teardown(void)152{153 efi_virtmap_unload();154}155 156static int __init riscv_dmi_init(void)157{158 /*159 * On riscv, DMI depends on UEFI, and dmi_setup() needs to160 * be called early because dmi_id_init(), which is an arch_initcall161 * itself, depends on dmi_scan_machine() having been called already.162 */163 dmi_setup();164 165 return 0;166}167core_initcall(riscv_dmi_init);168