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}