1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Extensible Firmware Interface
  4 *
  5 * Copyright (C) 2020 Western Digital Corporation or its affiliates.
  6 *
  7 * Based on Extensible Firmware Interface Specification version 2.4
  8 * Adapted from drivers/firmware/efi/arm-runtime.c
  9 *
 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 all
 64 * 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 to
160	 * be called early because dmi_id_init(), which is an arch_initcall
161	 * itself, depends on dmi_scan_machine() having been called already.
162	 */
163	dmi_setup();
164
165	return 0;
166}
167core_initcall(riscv_dmi_init);