linux/arch/arm64/kernel/efi-rt-wrapper.S

39 lines
814 B
ArmAsm

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2018 Linaro Ltd <ard.biesheuvel@linaro.org>
*/
#include <linux/linkage.h>
ENTRY(__efi_rt_asm_wrapper)
stp x29, x30, [sp, #-32]!
mov x29, sp
/*
* Register x18 is designated as the 'platform' register by the AAPCS,
* which means firmware running at the same exception level as the OS
* (such as UEFI) should never touch it.
*/
stp x1, x18, [sp, #16]
/*
* We are lucky enough that no EFI runtime services take more than
* 5 arguments, so all are passed in registers rather than via the
* stack.
*/
mov x8, x0
mov x0, x2
mov x1, x3
mov x2, x4
mov x3, x5
mov x4, x6
blr x8
ldp x1, x2, [sp, #16]
cmp x2, x18
ldp x29, x30, [sp], #32
b.ne 0f
ret
0: b efi_handle_corrupted_x18 // tail call
ENDPROC(__efi_rt_asm_wrapper)