1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * arch/arm/lib/call_with_stack.S
4 *
5 * Copyright (C) 2011 ARM Ltd.
6 * Written by Will Deacon <will.deacon@arm.com>
7 */
8
9#include <linux/linkage.h>
10#include <asm/assembler.h>
11#include <asm/unwind.h>
12
13/*
14 * void call_with_stack(void (*fn)(void *), void *arg, void *sp)
15 *
16 * Change the stack to that pointed at by sp, then invoke fn(arg) with
17 * the new stack.
18 *
19 * The sequence below follows the APCS frame convention for frame pointer
20 * unwinding, and implements the unwinder annotations needed by the EABI
21 * unwinder.
22 */
23
24ENTRY(call_with_stack)
25#if defined(CONFIG_UNWINDER_FRAME_POINTER) && defined(CONFIG_CC_IS_GCC)
26	mov	ip, sp
27	push	{fp, ip, lr, pc}
28	sub	fp, ip, #4
29#else
30UNWIND( .fnstart		)
31UNWIND( .save	{fpreg, lr}	)
32	push	{fpreg, lr}
33UNWIND( .setfp	fpreg, sp	)
34	mov	fpreg, sp
35#endif
36	mov	sp, r2
37	mov	r2, r0
38	mov	r0, r1
39
40	bl_r	r2
41
42#if defined(CONFIG_UNWINDER_FRAME_POINTER) && defined(CONFIG_CC_IS_GCC)
43	ldmdb	fp, {fp, sp, pc}
44#else
45	mov	sp, fpreg
46	pop	{fpreg, pc}
47UNWIND( .fnend			)
48#endif
49ENDPROC(call_with_stack)
50