1/* Implementation of profiling support.  ARM EABI version.
2   Copyright (C) 2008-2022 Free Software Foundation, Inc.
3   This file is part of the GNU C Library.
4
5   The GNU C Library is free software; you can redistribute it and/or
6   modify it under the terms of the GNU Lesser General Public
7   License as published by the Free Software Foundation; either
8   version 2.1 of the License, or (at your option) any later version.
9
10   The GNU C Library is distributed in the hope that it will be useful,
11   but WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13   Lesser General Public License for more details.
14
15   You should have received a copy of the GNU Lesser General Public
16   License along with the GNU C Library.  If not, see
17   <https://www.gnu.org/licenses/>.  */
18
19/* Don't call mcount when calling mcount...  */
20#undef PROF
21
22#include <sysdep.h>
23
24#undef mcount
25
26#ifdef __thumb2__
27	.thumb
28#endif
29	.syntax unified
30
31
32/* Use an assembly stub with a special ABI.  The calling lr has been
33   pushed to the stack (which will be misaligned).  We should preserve
34   all registers except ip and pop a word off the stack.
35
36   NOTE: This assumes mcount_internal does not clobber any non-core
37   (coprocessor) registers.  Currently this is true, but may require
38   additional attention in the future.
39
40   The calling sequence looks something like:
41func:
42   push {lr}
43   bl __gnu_mcount_nc
44   <function body>
45*/
46
47ENTRY(__gnu_mcount_nc)
48	push {r0, r1, r2, r3, lr}
49	cfi_adjust_cfa_offset (20)
50	cfi_rel_offset (r0, 0)
51	cfi_rel_offset (r1, 4)
52	cfi_rel_offset (r2, 8)
53	cfi_rel_offset (r3, 12)
54	cfi_rel_offset (lr, 16)
55	bic r1, lr, #1
56	ldr r0, [sp, #20]
57	bl __mcount_internal
58	pop {r0, r1, r2, r3, ip, lr}
59	cfi_adjust_cfa_offset (-24)
60	cfi_restore (r0)
61	cfi_restore (r1)
62	cfi_restore (r2)
63	cfi_restore (r3)
64	cfi_register (lr, ip)
65	bx ip
66END(__gnu_mcount_nc)
67
68
69#include <gcc-compat.h>
70#include <shlib-compat.h>
71
72/* The new __gnu_mcount_nc entry point was introduced in 4.4, so the
73   static library needs the old one only to support older compilers.
74   Even in a configuration that only cares about newer compilers, the
75   shared library might need it only for strict ABI compatibility.  */
76
77#if GCC_COMPAT (4, 3) || SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_19)
78
79/* Provide old mcount for backwards compatibility.  This requires
80   code be compiled with APCS frame pointers.  */
81
82ENTRY(__mcount_arm_compat)
83	push	{r0, r1, r2, r3, fp, lr}
84	cfi_adjust_cfa_offset (24)
85	cfi_rel_offset (r0, 0)
86	cfi_rel_offset (r1, 4)
87	cfi_rel_offset (r2, 8)
88	cfi_rel_offset (r3, 12)
89	cfi_rel_offset (fp, 16)
90	cfi_rel_offset (lr, 20)
91	movs r0, fp
92	ittt ne
93	ldrne r0, [r0, #-4]
94	movsne r1, lr
95	blne __mcount_internal
96# if defined (__ARM_ARCH_4T__) && defined (__THUMB_INTERWORK__)
97	pop	{r0, r1, r2, r3, fp, lr}
98	cfi_adjust_cfa_offset (-24)
99	cfi_restore (r0)
100	cfi_restore (r1)
101	cfi_restore (r2)
102	cfi_restore (r3)
103	cfi_restore (fp)
104	cfi_restore (lr)
105	bx lr
106# else
107	pop	{r0, r1, r2, r3, fp, pc}
108# endif
109END(__mcount_arm_compat)
110
111#endif
112
113#if GCC_COMPAT (4, 3)
114
115strong_alias (__mcount_arm_compat, _mcount)
116
117/* The canonical name for the function is `_mcount' in both C and asm,
118   but some old asm code might assume it's `mcount'.  */
119weak_alias (_mcount, mcount)
120
121#elif SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_19)
122
123compat_symbol (libc, __mcount_arm_compat, _mcount, GLIBC_2_0)
124
125strong_alias (__mcount_arm_compat, __mcount_arm_compat_1)
126compat_symbol (libc, __mcount_arm_compat_1, mcount, GLIBC_2_0)
127
128#endif
129