diff options
Diffstat (limited to 'arch/arm/kernel/efi.c')
| -rw-r--r-- | arch/arm/kernel/efi.c | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/arch/arm/kernel/efi.c b/arch/arm/kernel/efi.c new file mode 100644 index 000000000..e50ad7eef --- /dev/null +++ b/arch/arm/kernel/efi.c @@ -0,0 +1,154 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2015 Linaro Ltd <ard.biesheuvel@linaro.org> + */ + +#include <linux/efi.h> +#include <linux/memblock.h> +#include <asm/efi.h> +#include <asm/mach/map.h> +#include <asm/mmu_context.h> + +static int __init set_permissions(pte_t *ptep, unsigned long addr, void *data) +{ + efi_memory_desc_t *md = data; + pte_t pte = *ptep; + + if (md->attribute & EFI_MEMORY_RO) + pte = set_pte_bit(pte, __pgprot(L_PTE_RDONLY)); + if (md->attribute & EFI_MEMORY_XP) + pte = set_pte_bit(pte, __pgprot(L_PTE_XN)); + set_pte_ext(ptep, pte, PTE_EXT_NG); + return 0; +} + +int __init efi_set_mapping_permissions(struct mm_struct *mm, + efi_memory_desc_t *md) +{ + unsigned long base, size; + + base = md->virt_addr; + size = md->num_pages << EFI_PAGE_SHIFT; + + /* + * We can only use apply_to_page_range() if we can guarantee that the + * entire region was mapped using pages. This should be the case if the + * region does not cover any naturally aligned SECTION_SIZE sized + * blocks. + */ + if (round_down(base + size, SECTION_SIZE) < + round_up(base, SECTION_SIZE) + SECTION_SIZE) + return apply_to_page_range(mm, base, size, set_permissions, md); + + return 0; +} + +int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md) +{ + struct map_desc desc = { + .virtual = md->virt_addr, + .pfn = __phys_to_pfn(md->phys_addr), + .length = md->num_pages * EFI_PAGE_SIZE, + }; + + /* + * Order is important here: memory regions may have all of the + * bits below set (and usually do), so we check them in order of + * preference. + */ + if (md->attribute & EFI_MEMORY_WB) + desc.type = MT_MEMORY_RWX; + else if (md->attribute & EFI_MEMORY_WT) + desc.type = MT_MEMORY_RWX_NONCACHED; + else if (md->attribute & EFI_MEMORY_WC) + desc.type = MT_DEVICE_WC; + else + desc.type = MT_DEVICE; + + create_mapping_late(mm, &desc, true); + + /* + * If stricter permissions were specified, apply them now. + */ + if (md->attribute & (EFI_MEMORY_RO | EFI_MEMORY_XP)) + return efi_set_mapping_permissions(mm, md); + return 0; +} + +static unsigned long __initdata screen_info_table = EFI_INVALID_TABLE_ADDR; +static unsigned long __initdata cpu_state_table = EFI_INVALID_TABLE_ADDR; + +const efi_config_table_type_t efi_arch_tables[] __initconst = { + {LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID, &screen_info_table}, + {LINUX_EFI_ARM_CPU_STATE_TABLE_GUID, &cpu_state_table}, + {} +}; + +static void __init load_screen_info_table(void) +{ + struct screen_info *si; + + if (screen_info_table != EFI_INVALID_TABLE_ADDR) { + si = early_memremap_ro(screen_info_table, sizeof(*si)); + if (!si) { + pr_err("Could not map screen_info config table\n"); + return; + } + screen_info = *si; + early_memunmap(si, sizeof(*si)); + + /* dummycon on ARM needs non-zero values for columns/lines */ + screen_info.orig_video_cols = 80; + screen_info.orig_video_lines = 25; + + if (memblock_is_map_memory(screen_info.lfb_base)) + memblock_mark_nomap(screen_info.lfb_base, + screen_info.lfb_size); + } +} + +static void __init load_cpu_state_table(void) +{ + if (cpu_state_table != EFI_INVALID_TABLE_ADDR) { + struct efi_arm_entry_state *state; + bool dump_state = true; + + state = early_memremap_ro(cpu_state_table, + sizeof(struct efi_arm_entry_state)); + if (state == NULL) { + pr_warn("Unable to map CPU entry state table.\n"); + return; + } + + if ((state->sctlr_before_ebs & 1) == 0) + pr_warn(FW_BUG "EFI stub was entered with MMU and Dcache disabled, please fix your firmware!\n"); + else if ((state->sctlr_after_ebs & 1) == 0) + pr_warn(FW_BUG "ExitBootServices() returned with MMU and Dcache disabled, please fix your firmware!\n"); + else + dump_state = false; + + if (dump_state || efi_enabled(EFI_DBG)) { + pr_info("CPSR at EFI stub entry : 0x%08x\n", + state->cpsr_before_ebs); + pr_info("SCTLR at EFI stub entry : 0x%08x\n", + state->sctlr_before_ebs); + pr_info("CPSR after ExitBootServices() : 0x%08x\n", + state->cpsr_after_ebs); + pr_info("SCTLR after ExitBootServices(): 0x%08x\n", + state->sctlr_after_ebs); + } + early_memunmap(state, sizeof(struct efi_arm_entry_state)); + } +} + +void __init arm_efi_init(void) +{ + efi_init(); + + load_screen_info_table(); + + /* ARM does not permit early mappings to persist across paging_init() */ + efi_memmap_unmap(); + + load_cpu_state_table(); +} |