xref: /openbmc/linux/arch/mips/kernel/mcount.S (revision 538f1952)
1/*
2 * MIPS specific _mcount support
3 *
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License.  See the file "COPYING" in the main directory of this archive for
6 * more details.
7 *
8 * Copyright (C) 2009 Lemote Inc. & DSLab, Lanzhou University, China
9 * Author: Wu Zhangjin <wuzj@lemote.com>
10 */
11
12#include <asm/regdef.h>
13#include <asm/stackframe.h>
14#include <asm/ftrace.h>
15
16	.text
17	.set noreorder
18	.set noat
19
20	.macro MCOUNT_SAVE_REGS
21	PTR_SUBU	sp, PT_SIZE
22	PTR_S	ra, PT_R31(sp)
23	PTR_S	AT, PT_R1(sp)
24	PTR_S	a0, PT_R4(sp)
25	PTR_S	a1, PT_R5(sp)
26	PTR_S	a2, PT_R6(sp)
27	PTR_S	a3, PT_R7(sp)
28#ifdef CONFIG_64BIT
29	PTR_S	a4, PT_R8(sp)
30	PTR_S	a5, PT_R9(sp)
31	PTR_S	a6, PT_R10(sp)
32	PTR_S	a7, PT_R11(sp)
33#endif
34	.endm
35
36	.macro MCOUNT_RESTORE_REGS
37	PTR_L	ra, PT_R31(sp)
38	PTR_L	AT, PT_R1(sp)
39	PTR_L	a0, PT_R4(sp)
40	PTR_L	a1, PT_R5(sp)
41	PTR_L	a2, PT_R6(sp)
42	PTR_L	a3, PT_R7(sp)
43#ifdef CONFIG_64BIT
44	PTR_L	a4, PT_R8(sp)
45	PTR_L	a5, PT_R9(sp)
46	PTR_L	a6, PT_R10(sp)
47	PTR_L	a7, PT_R11(sp)
48#endif
49#ifdef CONFIG_64BIT
50	PTR_ADDIU	sp, PT_SIZE
51#else
52	PTR_ADDIU	sp, (PT_SIZE + 8)
53#endif
54.endm
55
56	.macro RETURN_BACK
57	jr ra
58	 move ra, AT
59	.endm
60
61#ifdef CONFIG_DYNAMIC_FTRACE
62
63NESTED(ftrace_caller, PT_SIZE, ra)
64	.globl _mcount
65_mcount:
66	b	ftrace_stub
67	 nop
68	lw	t0, function_trace_stop
69	bnez	t0, ftrace_stub
70	 nop
71
72	MCOUNT_SAVE_REGS
73
74	move	a0, ra		/* arg1: next ip, selfaddr */
75	.globl ftrace_call
76ftrace_call:
77	nop	/* a placeholder for the call to a real tracing function */
78	 move	a1, AT		/* arg2: the caller's next ip, parent */
79
80	MCOUNT_RESTORE_REGS
81	.globl ftrace_stub
82ftrace_stub:
83	RETURN_BACK
84	END(ftrace_caller)
85
86#else	/* ! CONFIG_DYNAMIC_FTRACE */
87
88NESTED(_mcount, PT_SIZE, ra)
89	lw	t0, function_trace_stop
90	bnez	t0, ftrace_stub
91	 nop
92	PTR_LA	t0, ftrace_stub
93	PTR_L	t1, ftrace_trace_function /* Prepare t1 for (1) */
94	bne	t0, t1, static_trace
95	 nop
96	b	ftrace_stub
97	 nop
98
99static_trace:
100	MCOUNT_SAVE_REGS
101
102	move	a0, ra		/* arg1: next ip, selfaddr */
103	jalr	t1	/* (1) call *ftrace_trace_function */
104	 move	a1, AT		/* arg2: the caller's next ip, parent */
105
106	MCOUNT_RESTORE_REGS
107	.globl ftrace_stub
108ftrace_stub:
109	RETURN_BACK
110	END(_mcount)
111
112#endif	/* ! CONFIG_DYNAMIC_FTRACE */
113
114	.set at
115	.set reorder
116