1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2015 Linaro Ltd <ard.biesheuvel@linaro.org>
4 */
5
6 #include <linux/efi.h>
7 #include <linux/memblock.h>
8 #include <linux/screen_info.h>
9
10 #include <asm/efi.h>
11 #include <asm/mach/map.h>
12 #include <asm/mmu_context.h>
13
14 static int __init set_permissions(pte_t *ptep, unsigned long addr, void *data)
15 {
16 efi_memory_desc_t *md = data;
17 pte_t pte = *ptep;
18
19 if (md->attribute & EFI_MEMORY_RO)
20 pte = set_pte_bit(pte, __pgprot(L_PTE_RDONLY));
21 if (md->attribute & EFI_MEMORY_XP)
22 pte = set_pte_bit(pte, __pgprot(L_PTE_XN));
23 set_pte_ext(ptep, pte, PTE_EXT_NG);
24 return 0;
25 }
26
27 int __init efi_set_mapping_permissions(struct mm_struct *mm,
28 efi_memory_desc_t *md,
29 bool ignored)
30 {
31 unsigned long base, size;
32
33 base = md->virt_addr;
34 size = md->num_pages << EFI_PAGE_SHIFT;
35
36 /*
37 * We can only use apply_to_page_range() if we can guarantee that the
38 * entire region was mapped using pages. This should be the case if the
39 * region does not cover any naturally aligned SECTION_SIZE sized
40 * blocks.
41 */
42 if (round_down(base + size, SECTION_SIZE) <
43 round_up(base, SECTION_SIZE) + SECTION_SIZE)
44 return apply_to_page_range(mm, base, size, set_permissions, md);
45
46 return 0;
47 }
48
49 int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md)
50 {
51 struct map_desc desc = {
52 .virtual = md->virt_addr,
53 .pfn = __phys_to_pfn(md->phys_addr),
54 .length = md->num_pages * EFI_PAGE_SIZE,
55 };
56
57 /*
58 * Order is important here: memory regions may have all of the
59 * bits below set (and usually do), so we check them in order of
60 * preference.
61 */
62 if (md->attribute & EFI_MEMORY_WB)
63 desc.type = MT_MEMORY_RWX;
64 else if (md->attribute & EFI_MEMORY_WT)
65 desc.type = MT_MEMORY_RWX_NONCACHED;
66 else if (md->attribute & EFI_MEMORY_WC)
67 desc.type = MT_DEVICE_WC;
68 else
69 desc.type = MT_DEVICE;
70
71 create_mapping_late(mm, &desc, true);
72
73 /*
74 * If stricter permissions were specified, apply them now.
75 */
76 if (md->attribute & (EFI_MEMORY_RO | EFI_MEMORY_XP))
77 return efi_set_mapping_permissions(mm, md, false);
78 return 0;
79 }
80
81 static unsigned long __initdata cpu_state_table = EFI_INVALID_TABLE_ADDR;
82
83 const efi_config_table_type_t efi_arch_tables[] __initconst = {
84 {LINUX_EFI_ARM_CPU_STATE_TABLE_GUID, &cpu_state_table},
85 {}
86 };
87
88 static void __init load_cpu_state_table(void)
89 {
90 if (cpu_state_table != EFI_INVALID_TABLE_ADDR) {
91 struct efi_arm_entry_state *state;
92 bool dump_state = true;
93
94 state = early_memremap_ro(cpu_state_table,
95 sizeof(struct efi_arm_entry_state));
96 if (state == NULL) {
97 pr_warn("Unable to map CPU entry state table.\n");
98 return;
99 }
100
101 if ((state->sctlr_before_ebs & 1) == 0)
102 pr_warn(FW_BUG "EFI stub was entered with MMU and Dcache disabled, please fix your firmware!\n");
103 else if ((state->sctlr_after_ebs & 1) == 0)
104 pr_warn(FW_BUG "ExitBootServices() returned with MMU and Dcache disabled, please fix your firmware!\n");
105 else
106 dump_state = false;
107
108 if (dump_state || efi_enabled(EFI_DBG)) {
109 pr_info("CPSR at EFI stub entry : 0x%08x\n",
110 state->cpsr_before_ebs);
111 pr_info("SCTLR at EFI stub entry : 0x%08x\n",
112 state->sctlr_before_ebs);
113 pr_info("CPSR after ExitBootServices() : 0x%08x\n",
114 state->cpsr_after_ebs);
115 pr_info("SCTLR after ExitBootServices(): 0x%08x\n",
116 state->sctlr_after_ebs);
117 }
118 early_memunmap(state, sizeof(struct efi_arm_entry_state));
119 }
120 }
121
122 void __init arm_efi_init(void)
123 {
124 efi_init();
125
126 /* ARM does not permit early mappings to persist across paging_init() */
127 efi_memmap_unmap();
128
129 load_cpu_state_table();
130 }
131
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