arch/arm64/include/asm/efi.h

#ifndef _ASM_EFI_H
#define _ASM_EFI_H

#include <asm/io.h>
#include <asm/neon.h>

#ifdef CONFIG_EFI
extern void efi_init(void);
extern void efi_idmap_init(void);
extern void efi_virtmap_init(void);
#else
#define efi_init()
#define efi_idmap_init()
#define efi_virtmap_init()
#endif

#define efi_call_virt(f, ...)						\
({									\
	efi_##f##_t *__f;						\
	efi_status_t __s;						\
									\
	kernel_neon_begin();						\
	efi_virtmap_load();						\
	__f = efi.systab->runtime->f;					\
	__s = __f(__VA_ARGS__);						\
	efi_virtmap_unload();						\
	kernel_neon_end();						\
	__s;								\
})

#define __efi_call_virt(f, ...)						\
({									\
	efi_##f##_t *__f;						\
									\
	kernel_neon_begin();						\
	efi_virtmap_load();						\
	__f = efi.systab->runtime->f;					\
	__f(__VA_ARGS__);						\
	efi_virtmap_unload();						\
	kernel_neon_end();						\
})

/* arch specific definitions used by the stub code */

/*
 * AArch64 requires the DTB to be 8-byte aligned in the first 512MiB from
 * start of kernel and may not cross a 2MiB boundary. We set alignment to
 * 2MiB so we know it won't cross a 2MiB boundary.
 */
#define EFI_FDT_ALIGN	SZ_2M   /* used by allocate_new_fdt_and_exit_boot() */
#define MAX_FDT_OFFSET	SZ_512M

#define efi_call_early(f, ...) sys_table_arg->boottime->f(__VA_ARGS__)

#define EFI_ALLOC_ALIGN		SZ_64K

/*
 * On ARM systems, virtually remapped UEFI runtime services are set up in three
 * distinct stages:
 * - The stub retrieves the final version of the memory map from UEFI, populates
 *   the virt_addr fields and calls the SetVirtualAddressMap() [SVAM] runtime
 *   service to communicate the new mapping to the firmware (Note that the new
 *   mapping is not live at this time)
 * - During early boot, the page tables are allocated and populated based on the
 *   virt_addr fields in the memory map, but only if all descriptors with the
 *   EFI_MEMORY_RUNTIME attribute have a non-zero value for virt_addr. If this
 *   succeeds, the EFI_VIRTMAP flag is set to indicate that the virtual mappings
 *   have been installed successfully.
 * - During an early initcall(), the UEFI Runtime Services are enabled and the
 *   EFI_RUNTIME_SERVICES bit set if some conditions are met, i.e., we need a
 *   non-early mapping of the UEFI system table, and we need to have the virtmap
 *   installed.
 */
#define EFI_VIRTMAP		EFI_ARCH_1

void efi_virtmap_load(void);
void efi_virtmap_unload(void);

#endif /* _ASM_EFI_H */