xref: /linux/arch/x86/platform/efi/efi_32.c (revision 03c11eb3b16dc0058589751dfd91f254be2be613)
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 
efi_map_region(efi_memory_desc_t * md)36 void __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((unsigned long)va, md->num_pages);
52 	} else {
53 		va = ioremap_cache(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 
efi_alloc_page_tables(void)68 int __init efi_alloc_page_tables(void)
69 {
70 	return 0;
71 }
72 
efi_sync_low_kernel_mappings(void)73 void efi_sync_low_kernel_mappings(void) {}
74 
efi_dump_pagetable(void)75 void __init efi_dump_pagetable(void)
76 {
77 #ifdef CONFIG_EFI_PGT_DUMP
78 	ptdump_walk_pgd_level(NULL, &init_mm);
79 #endif
80 }
81 
efi_setup_page_tables(unsigned long pa_memmap,unsigned num_pages)82 int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
83 {
84 	return 0;
85 }
86 
efi_map_region_fixed(efi_memory_desc_t * md)87 void __init efi_map_region_fixed(efi_memory_desc_t *md) {}
parse_efi_setup(u64 phys_addr,u32 data_len)88 void __init parse_efi_setup(u64 phys_addr, u32 data_len) {}
89 
90 efi_status_t efi_call_svam(efi_runtime_services_t * const *,
91 			   u32, u32, u32, void *, u32);
92 
efi_set_virtual_address_map(unsigned long memory_map_size,unsigned long descriptor_size,u32 descriptor_version,efi_memory_desc_t * virtual_map,unsigned long systab_phys)93 efi_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(initial_page_table);
108 	__flush_tlb_all();
109 
110 	gdt_descr.address = get_cpu_gdt_paddr(0);
111 	gdt_descr.size = GDT_SIZE - 1;
112 	load_gdt(&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(save_pgd);
124 	__flush_tlb_all();
125 
126 	return status;
127 }
128 
efi_runtime_update_mappings(void)129 void __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(md->virt_addr, md->num_pages);
140 		}
141 	}
142 }
143 
arch_efi_call_virt_setup(void)144 void arch_efi_call_virt_setup(void)
145 {
146 	efi_fpu_begin();
147 	firmware_restrict_branch_speculation_start();
148 }
149 
arch_efi_call_virt_teardown(void)150 void arch_efi_call_virt_teardown(void)
151 {
152 	firmware_restrict_branch_speculation_end();
153 	efi_fpu_end();
154 }
155