1/* Machine-specific calling sequence for `mcount' profiling function. x86-64 version.
2 Copyright (C) 2002-2020 Free Software Foundation, Inc.
3 Contributed by Andreas Jaeger <aj@suse.de>.
4 This file is part of the GNU C Library.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20/* Assembly stub to invoke _mcount(). Compiler generated code calls
21 this stub after executing a function's prologue and without saving any
22 registers. It is therefore necessary to preserve %rcx, %rdx, %rsi, %rdi,
23 %r8, %r9 as they may contain function arguments. */
24
25#include <sysdep.h>
26
27ENTRY(_mcount)
28 /* Allocate space for 7 registers. */
29 subq $56,%rsp
30 cfi_adjust_cfa_offset (56)
31 movq %rax,(%rsp)
32 cfi_rel_offset (rax, 0)
33 movq %rcx,8(%rsp)
34 cfi_rel_offset (rcx, 8)
35 movq %rdx,16(%rsp)
36 cfi_rel_offset (rdx, 16)
37 movq %rsi,24(%rsp)
38 cfi_rel_offset (rsi, 24)
39 movq %rdi,32(%rsp)
40 cfi_rel_offset (rdi, 32)
41 movq %r8,40(%rsp)
42 cfi_rel_offset (r8, 40)
43 movq %r9,48(%rsp)
44 cfi_rel_offset (r9, 48)
45
46 /* Setup parameter for __mcount_internal. */
47 /* selfpc is the return address on the stack. */
48 movq 56(%rsp),%rsi
49 /* Get frompc via the frame pointer. */
50 movq 8(%rbp),%rdi
51 call C_SYMBOL_NAME(__mcount_internal)
52 /* Pop the saved registers. Please note that `mcount' has no
53 return value. */
54 movq 48(%rsp),%r9
55 cfi_restore (r9)
56 movq 40(%rsp),%r8
57 cfi_restore (r8)
58 movq 32(%rsp),%rdi
59 cfi_restore (rdi)
60 movq 24(%rsp),%rsi
61 cfi_restore (rsi)
62 movq 16(%rsp),%rdx
63 cfi_restore (rdx)
64 movq 8(%rsp),%rcx
65 cfi_restore (rcx)
66 movq (%rsp),%rax
67 cfi_restore (rax)
68 addq $56,%rsp
69 cfi_adjust_cfa_offset (-56)
70 ret
71END(_mcount)
72
73#undef mcount
74weak_alias (_mcount, mcount)
75
76/* __fentry__ is different from _mcount in that it is called before
77 function prolog. This means (among other things) that it has non-standard
78 stack alignment on entry: (%RSP & 0xF) == 0. */
79
80ENTRY(__fentry__)
81 /* Allocate space for 7 registers
82 (+8 bytes for proper stack alignment). */
83 subq $64,%rsp
84 cfi_adjust_cfa_offset (64)
85 movq %rax,(%rsp)
86 cfi_rel_offset (rax, 0)
87 movq %rcx,8(%rsp)
88 cfi_rel_offset (rcx, 8)
89 movq %rdx,16(%rsp)
90 cfi_rel_offset (rdx, 16)
91 movq %rsi,24(%rsp)
92 cfi_rel_offset (rsi, 24)
93 movq %rdi,32(%rsp)
94 cfi_rel_offset (rdi, 32)
95 movq %r8,40(%rsp)
96 cfi_rel_offset (r8, 40)
97 movq %r9,48(%rsp)
98 cfi_rel_offset (r9, 48)
99
100 /* Setup parameter for __mcount_internal. */
101 /* selfpc is the return address on the stack. */
102 movq 64(%rsp),%rsi
103 /* caller is the return address above it */
104 movq 72(%rsp),%rdi
105 call C_SYMBOL_NAME(__mcount_internal)
106 /* Pop the saved registers. Please note that `__fentry__' has no
107 return value. */
108 movq 48(%rsp),%r9
109 cfi_restore (r9)
110 movq 40(%rsp),%r8
111 cfi_restore (r8)
112 movq 32(%rsp),%rdi
113 cfi_restore (rdi)
114 movq 24(%rsp),%rsi
115 cfi_restore (rsi)
116 movq 16(%rsp),%rdx
117 cfi_restore (rdx)
118 movq 8(%rsp),%rcx
119 cfi_restore (rcx)
120 movq (%rsp),%rax
121 cfi_restore (rax)
122 addq $64,%rsp
123 cfi_adjust_cfa_offset (-64)
124 ret
125END(__fentry__)
126