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
24 ENTRY(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
30 UNWIND( .fnstart )
31 UNWIND( .save {fpreg, lr} )
32 push {fpreg, lr}
33 UNWIND( .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}
47 UNWIND( .fnend )
48 #endif
49 .globl call_with_stack_end
50 call_with_stack_end:
51 ENDPROC(call_with_stack)
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