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
14static 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
27int __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
49int __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
81static unsigned long __initdata cpu_state_table = EFI_INVALID_TABLE_ADDR;
82
83const efi_config_table_type_t efi_arch_tables[] __initconst = {
84	{LINUX_EFI_ARM_CPU_STATE_TABLE_GUID, &cpu_state_table},
85	{}
86};
87
88static 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
122void __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