1/*
  2 * Extensible Firmware Interface
  3 *
  4 * Based on Extensible Firmware Interface Specification version 2.4
  5 *
  6 * Copyright (C) 2013, 2014 Linaro Ltd.
  7 *
  8 * This program is free software; you can redistribute it and/or modify
  9 * it under the terms of the GNU General Public License version 2 as
 10 * published by the Free Software Foundation.
 11 *
 12 */
 13
 14#include <linux/dmi.h>
 15#include <linux/efi.h>
 16#include <linux/io.h>
 17#include <linux/memblock.h>
 18#include <linux/mm_types.h>
 19#include <linux/preempt.h>
 20#include <linux/rbtree.h>
 21#include <linux/rwsem.h>
 22#include <linux/sched.h>
 23#include <linux/slab.h>
 24#include <linux/spinlock.h>
 25
 26#include <asm/cacheflush.h>
 27#include <asm/efi.h>
 28#include <asm/mmu.h>
 29#include <asm/pgalloc.h>
 30#include <asm/pgtable.h>
 31
 32extern u64 efi_system_table;
 33
 34#ifdef CONFIG_ARM64_PTDUMP_DEBUGFS
 35#include <asm/ptdump.h>
 36
 37static struct ptdump_info efi_ptdump_info = {
 38	.mm		= &efi_mm,
 39	.markers	= (struct addr_marker[]){
 40		{ 0,		"UEFI runtime start" },
 41		{ TASK_SIZE_64,	"UEFI runtime end" }
 42	},
 43	.base_addr	= 0,
 44};
 45
 46static int __init ptdump_init(void)
 47{
 48	if (!efi_enabled(EFI_RUNTIME_SERVICES))
 49		return 0;
 50
 51	return ptdump_debugfs_register(&efi_ptdump_info, "efi_page_tables");
 52}
 53device_initcall(ptdump_init);
 54
 55#endif
 56
 57static bool __init efi_virtmap_init(void)
 58{
 59	efi_memory_desc_t *md;
 60	bool systab_found;
 61
 62	efi_mm.pgd = pgd_alloc(&efi_mm);
 63	mm_init_cpumask(&efi_mm);
 64	init_new_context(NULL, &efi_mm);
 65
 66	systab_found = false;
 67	for_each_efi_memory_desc(md) {
 68		phys_addr_t phys = md->phys_addr;
 69		int ret;
 70
 71		if (!(md->attribute & EFI_MEMORY_RUNTIME))
 72			continue;
 73		if (md->virt_addr == 0)
 74			return false;
 75
 76		ret = efi_create_mapping(&efi_mm, md);
 77		if (ret) {
 78			pr_warn("  EFI remap %pa: failed to create mapping (%d)\n",
 79				&phys, ret);
 80			return false;
 81		}
 82		/*
 83		 * If this entry covers the address of the UEFI system table,
 84		 * calculate and record its virtual address.
 85		 */
 86		if (efi_system_table >= phys &&
 87		    efi_system_table < phys + (md->num_pages * EFI_PAGE_SIZE)) {
 88			efi.systab = (void *)(unsigned long)(efi_system_table -
 89							     phys + md->virt_addr);
 90			systab_found = true;
 91		}
 92	}
 93	if (!systab_found) {
 94		pr_err("No virtual mapping found for the UEFI System Table\n");
 95		return false;
 96	}
 97
 98	if (efi_memattr_apply_permissions(&efi_mm, efi_set_mapping_permissions))
 99		return false;
100
101	return true;
102}
103
104/*
105 * Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,
106 * non-early mapping of the UEFI system table and virtual mappings for all
107 * EFI_MEMORY_RUNTIME regions.
108 */
109static int __init arm_enable_runtime_services(void)
110{
111	u64 mapsize;
112
113	if (!efi_enabled(EFI_BOOT)) {
114		pr_info("EFI services will not be available.\n");
115		return 0;
116	}
117
118	if (efi_runtime_disabled()) {
119		pr_info("EFI runtime services will be disabled.\n");
120		return 0;
121	}
122
123	if (efi_enabled(EFI_RUNTIME_SERVICES)) {
124		pr_info("EFI runtime services access via paravirt.\n");
125		return 0;
126	}
127
128	pr_info("Remapping and enabling EFI services.\n");
129
130	mapsize = efi.memmap.desc_size * efi.memmap.nr_map;
131
132	if (efi_memmap_init_late(efi.memmap.phys_map, mapsize)) {
133		pr_err("Failed to remap EFI memory map\n");
134		return -ENOMEM;
135	}
136
137	if (!efi_virtmap_init()) {
138		pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n");
139		return -ENOMEM;
140	}
141
142	/* Set up runtime services function pointers */
143	efi_native_runtime_setup();
144	set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
145
146	return 0;
147}
148early_initcall(arm_enable_runtime_services);
149
150void efi_virtmap_load(void)
151{
152	preempt_disable();
153	efi_set_pgd(&efi_mm);
154}
155
156void efi_virtmap_unload(void)
157{
158	efi_set_pgd(current->active_mm);
159	preempt_enable();
160}
161
162
163static int __init arm_dmi_init(void)
164{
165	/*
166	 * On arm64/ARM, DMI depends on UEFI, and dmi_scan_machine() needs to
167	 * be called early because dmi_id_init(), which is an arch_initcall
168	 * itself, depends on dmi_scan_machine() having been called already.
169	 */
170	dmi_scan_machine();
171	if (dmi_available)
172		dmi_set_dump_stack_arch_desc();
173	return 0;
174}
175core_initcall(arm_dmi_init);