1/*
2 * arch/xtensa/kernel/mcount.S
3 *
4 * Xtensa specific mcount support
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License.  See the file "COPYING" in the main directory of this archive
8 * for more details.
9 *
10 * Copyright (C) 2013 Tensilica Inc.
11 */
12
13#include <linux/linkage.h>
14#include <asm/asmmacro.h>
15#include <asm/ftrace.h>
16
17/*
18 * Entry condition:
19 *
20 *   a2:	a0 of the caller in windowed ABI
21 *   a10:	a0 of the caller in call0 ABI
22 *
23 * In call0 ABI the function _mcount is called with the special ABI:
24 * its argument is in a10 and all the usual argument registers (a2 - a7)
25 * must be preserved in addition to callee-saved a12 - a15.
26 */
27
28ENTRY(_mcount)
29#if defined(__XTENSA_WINDOWED_ABI__)
30	abi_entry_default
31
32	movi	a4, ftrace_trace_function
33	l32i	a4, a4, 0
34	movi	a3, ftrace_stub
35	bne	a3, a4, 1f
36	abi_ret_default
37
381: 	xor	a7, a2, a1
39	movi	a3, 0x3fffffff
40	and	a7, a7, a3
41	xor	a7, a7, a1
42
43	xor	a6, a0, a1
44	and	a6, a6, a3
45	xor	a6, a6, a1
46	addi	a6, a6, -MCOUNT_INSN_SIZE
47	callx4	a4
48
49	abi_ret_default
50#elif defined(__XTENSA_CALL0_ABI__)
51	abi_entry_default
52
53	movi	a9, ftrace_trace_function
54	l32i	a9, a9, 0
55	movi	a11, ftrace_stub
56	bne	a9, a11, 1f
57	abi_ret_default
58
591:	abi_entry(28)
60	s32i	a0, sp, 0
61	s32i	a2, sp, 4
62	s32i	a3, sp, 8
63	s32i	a4, sp, 12
64	s32i	a5, sp, 16
65	s32i	a6, sp, 20
66	s32i	a7, sp, 24
67	addi	a2, a10, -MCOUNT_INSN_SIZE
68	callx0	a9
69	l32i	a0, sp, 0
70	l32i	a2, sp, 4
71	l32i	a3, sp, 8
72	l32i	a4, sp, 12
73	l32i	a5, sp, 16
74	l32i	a6, sp, 20
75	l32i	a7, sp, 24
76	abi_ret(28)
77#else
78#error Unsupported Xtensa ABI
79#endif
80ENDPROC(_mcount)
81EXPORT_SYMBOL(_mcount)
82
83ENTRY(ftrace_stub)
84	abi_entry_default
85	abi_ret_default
86ENDPROC(ftrace_stub)
87