1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Extensible Firmware Interface
4 *
5 * Based on Extensible Firmware Interface Specification version 1.0
6 *
7 * Copyright (C) 1999 VA Linux Systems
8 * Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
9 * Copyright (C) 1999-2002 Hewlett-Packard Co.
10 * David Mosberger-Tang <davidm@hpl.hp.com>
11 * Stephane Eranian <eranian@hpl.hp.com>
12 *
13 * All EFI Runtime Services are not implemented yet as EFI only
14 * supports physical mode addressing on SoftSDV. This is to be fixed
15 * in a future version. --drummond 1999-07-20
16 *
17 * Implemented EFI runtime services and virtual mode calls. --davidm
18 *
19 * Goutham Rao: <goutham.rao@intel.com>
20 * Skip non-WB memory and ignore empty memory ranges.
21 */
22
23#include <linux/kernel.h>
24#include <linux/types.h>
25#include <linux/ioport.h>
26#include <linux/efi.h>
27#include <linux/pgtable.h>
28
29#include <asm/io.h>
30#include <asm/desc.h>
31#include <asm/page.h>
32#include <asm/set_memory.h>
33#include <asm/tlbflush.h>
34#include <asm/efi.h>
35
36void __init efi_map_region(efi_memory_desc_t *md)
37{
38 u64 start_pfn, end_pfn, end;
39 unsigned long size;
40 void *va;
41
42 start_pfn = PFN_DOWN(md->phys_addr);
43 size = md->num_pages << PAGE_SHIFT;
44 end = md->phys_addr + size;
45 end_pfn = PFN_UP(end);
46
47 if (pfn_range_is_mapped(start_pfn, end_pfn)) {
48 va = __va(md->phys_addr);
49
50 if (!(md->attribute & EFI_MEMORY_WB))
51 set_memory_uc(addr: (unsigned long)va, numpages: md->num_pages);
52 } else {
53 va = ioremap_cache(offset: md->phys_addr, size);
54 }
55
56 md->virt_addr = (unsigned long)va;
57 if (!va)
58 pr_err("ioremap of 0x%llX failed!\n", md->phys_addr);
59}
60
61/*
62 * To make EFI call EFI runtime service in physical addressing mode we need
63 * prolog/epilog before/after the invocation to claim the EFI runtime service
64 * handler exclusively and to duplicate a memory mapping in low memory space,
65 * say 0 - 3G.
66 */
67
68int __init efi_alloc_page_tables(void)
69{
70 return 0;
71}
72
73void efi_sync_low_kernel_mappings(void) {}
74
75void __init efi_dump_pagetable(void)
76{
77#ifdef CONFIG_EFI_PGT_DUMP
78 ptdump_walk_pgd_level(NULL, mm: &init_mm);
79#endif
80}
81
82int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
83{
84 return 0;
85}
86
87void __init efi_map_region_fixed(efi_memory_desc_t *md) {}
88void __init parse_efi_setup(u64 phys_addr, u32 data_len) {}
89
90efi_status_t efi_call_svam(efi_runtime_services_t * const *,
91 u32, u32, u32, void *, u32);
92
93efi_status_t __init efi_set_virtual_address_map(unsigned long memory_map_size,
94 unsigned long descriptor_size,
95 u32 descriptor_version,
96 efi_memory_desc_t *virtual_map,
97 unsigned long systab_phys)
98{
99 const efi_system_table_t *systab = (efi_system_table_t *)systab_phys;
100 struct desc_ptr gdt_descr;
101 efi_status_t status;
102 unsigned long flags;
103 pgd_t *save_pgd;
104
105 /* Current pgd is swapper_pg_dir, we'll restore it later: */
106 save_pgd = swapper_pg_dir;
107 load_cr3(pgdir: initial_page_table);
108 __flush_tlb_all();
109
110 gdt_descr.address = get_cpu_gdt_paddr(cpu: 0);
111 gdt_descr.size = GDT_SIZE - 1;
112 load_gdt(dtr: &gdt_descr);
113
114 /* Disable interrupts around EFI calls: */
115 local_irq_save(flags);
116 status = efi_call_svam(&systab->runtime,
117 memory_map_size, descriptor_size,
118 descriptor_version, virtual_map,
119 __pa(&efi.runtime));
120 local_irq_restore(flags);
121
122 load_fixmap_gdt(0);
123 load_cr3(pgdir: save_pgd);
124 __flush_tlb_all();
125
126 return status;
127}
128
129void __init efi_runtime_update_mappings(void)
130{
131 if (__supported_pte_mask & _PAGE_NX) {
132 efi_memory_desc_t *md;
133
134 /* Make EFI runtime service code area executable */
135 for_each_efi_memory_desc(md) {
136 if (md->type != EFI_RUNTIME_SERVICES_CODE)
137 continue;
138
139 set_memory_x(addr: md->virt_addr, numpages: md->num_pages);
140 }
141 }
142}
143
144void arch_efi_call_virt_setup(void)
145{
146 efi_fpu_begin();
147 firmware_restrict_branch_speculation_start();
148}
149
150void arch_efi_call_virt_teardown(void)
151{
152 firmware_restrict_branch_speculation_end();
153 efi_fpu_end();
154}
155

source code of linux/arch/x86/platform/efi/efi_32.c