arch/x86/platform/efi/efi_32.c

Source file repositories/reference/linux-study-clean/arch/x86/platform/efi/efi_32.c

File Facts

System
Linux kernel
Corpus path
arch/x86/platform/efi/efi_32.c
Extension
.c
Size
3850 bytes
Lines
155
Domain
Architecture Layer
Bucket
arch/x86
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

void efi_sync_low_kernel_mappings(void) {}

void __init efi_dump_pagetable(void)
{
#ifdef CONFIG_EFI_PGT_DUMP
	ptdump_walk_pgd_level(NULL, &init_mm);
#endif
}

int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
{
	return 0;
}

void __init efi_map_region_fixed(efi_memory_desc_t *md) {}
void __init parse_efi_setup(u64 phys_addr, u32 data_len) {}

efi_status_t efi_call_svam(efi_runtime_services_t * const *,
			   u32, u32, u32, void *, u32);

efi_status_t __init efi_set_virtual_address_map(unsigned long memory_map_size,
						unsigned long descriptor_size,
						u32 descriptor_version,
						efi_memory_desc_t *virtual_map,
						unsigned long systab_phys)
{
	const efi_system_table_t *systab = (efi_system_table_t *)systab_phys;
	struct desc_ptr gdt_descr;
	efi_status_t status;
	unsigned long flags;
	pgd_t *save_pgd;

	/* Current pgd is swapper_pg_dir, we'll restore it later: */
	save_pgd = swapper_pg_dir;
	load_cr3(initial_page_table);
	__flush_tlb_all();

	gdt_descr.address = get_cpu_gdt_paddr(0);
	gdt_descr.size = GDT_SIZE - 1;
	load_gdt(&gdt_descr);

	/* Disable interrupts around EFI calls: */
	local_irq_save(flags);
	status = efi_call_svam(&systab->runtime,
			       memory_map_size, descriptor_size,
			       descriptor_version, virtual_map,
			       __pa(&efi.runtime));
	local_irq_restore(flags);

	load_fixmap_gdt(0);
	load_cr3(save_pgd);
	__flush_tlb_all();

	return status;
}

void __init efi_runtime_update_mappings(void)
{
	if (__supported_pte_mask & _PAGE_NX) {
		efi_memory_desc_t *md;

		/* Make EFI runtime service code area executable */
		for_each_efi_memory_desc(md) {
			if (md->type != EFI_RUNTIME_SERVICES_CODE)
				continue;

			set_memory_x(md->virt_addr, md->num_pages);
		}
	}
}

void arch_efi_call_virt_setup(void)
{
	efi_fpu_begin();
	firmware_restrict_branch_speculation_start();
}

void arch_efi_call_virt_teardown(void)
{
	firmware_restrict_branch_speculation_end();
	efi_fpu_end();
}

Annotation

Implementation Notes