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, address: base, size, fn: set_permissions, data: 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, ignored: 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 | |