1/*
2 * Low-level ftrace handling
3 *
4 * Copyright (C) 2009 Michal Simek <monstr@monstr.eu>
5 * Copyright (C) 2009 PetaLogix
6 *
7 * This file is subject to the terms and conditions of the GNU General
8 * Public License. See the file COPYING in the main directory of this
9 * archive for more details.
10 */
11
12#include <linux/linkage.h>
13
14#define NOALIGN_ENTRY(name)	.globl name; name:
15
16/* FIXME MS: I think that I don't need to save all regs */
17#define SAVE_REGS		\
18	addik	r1, r1, -120;	\
19	swi	r2, r1, 4;	\
20	swi	r3, r1, 8;	\
21	swi	r4, r1, 12;	\
22	swi	r5, r1, 116;	\
23	swi	r6, r1, 16;	\
24	swi	r7, r1, 20;	\
25	swi	r8, r1, 24;	\
26	swi	r9, r1, 28;	\
27	swi	r10, r1, 32;	\
28	swi	r11, r1, 36;	\
29	swi	r12, r1, 40;	\
30	swi	r13, r1, 44;	\
31	swi	r14, r1, 48;	\
32	swi	r16, r1, 52;	\
33	swi	r17, r1, 56;	\
34	swi	r18, r1, 60;	\
35	swi	r19, r1, 64;	\
36	swi	r20, r1, 68;	\
37	swi	r21, r1, 72;	\
38	swi	r22, r1, 76;	\
39	swi	r23, r1, 80;	\
40	swi	r24, r1, 84;	\
41	swi	r25, r1, 88;	\
42	swi	r26, r1, 92;	\
43	swi	r27, r1, 96;	\
44	swi	r28, r1, 100;	\
45	swi	r29, r1, 104;	\
46	swi	r30, r1, 108;	\
47	swi	r31, r1, 112;
48
49#define RESTORE_REGS		\
50	lwi	r2, r1, 4;	\
51	lwi	r3, r1, 8;	\
52	lwi	r4, r1, 12;	\
53	lwi	r5, r1, 116;	\
54	lwi	r6, r1, 16;	\
55	lwi	r7, r1, 20;	\
56	lwi	r8, r1, 24;	\
57	lwi	r9, r1, 28;	\
58	lwi	r10, r1, 32;	\
59	lwi	r11, r1, 36;	\
60	lwi	r12, r1, 40;	\
61	lwi	r13, r1, 44;	\
62	lwi	r14, r1, 48;	\
63	lwi	r16, r1, 52;	\
64	lwi	r17, r1, 56;	\
65	lwi	r18, r1, 60;	\
66	lwi	r19, r1, 64;	\
67	lwi	r20, r1, 68;	\
68	lwi	r21, r1, 72;	\
69	lwi	r22, r1, 76;	\
70	lwi	r23, r1, 80;	\
71	lwi	r24, r1, 84;	\
72	lwi	r25, r1, 88;	\
73	lwi	r26, r1, 92;	\
74	lwi	r27, r1, 96;	\
75	lwi	r28, r1, 100;	\
76	lwi	r29, r1, 104;	\
77	lwi	r30, r1, 108;	\
78	lwi	r31, r1, 112;	\
79	addik	r1, r1, 120;
80
81ENTRY(ftrace_stub)
82	rtsd	r15, 8;
83	nop;
84
85ENTRY(_mcount)
86#ifdef CONFIG_DYNAMIC_FTRACE
87ENTRY(ftrace_caller)
88	/* MS: It is just barrier which is removed from C code */
89	rtsd	r15, 8
90	nop
91#endif /* CONFIG_DYNAMIC_FTRACE */
92	SAVE_REGS
93	swi	r15, r1, 0;
94#ifdef CONFIG_FUNCTION_GRAPH_TRACER
95#ifndef CONFIG_DYNAMIC_FTRACE
96	lwi	r5, r0, ftrace_graph_return;
97	addik	r6, r0, ftrace_stub; /* asm implementation */
98	cmpu	r5, r5, r6; /* ftrace_graph_return != ftrace_stub */
99	beqid	r5, end_graph_tracer;
100	nop;
101
102	lwi	r6, r0, ftrace_graph_entry;
103	addik	r5, r0, ftrace_graph_entry_stub; /* implemented in C */
104	cmpu	r5, r5, r6; /* ftrace_graph_entry != ftrace_graph_entry_stub */
105	beqid	r5, end_graph_tracer;
106	nop;
107#else /* CONFIG_DYNAMIC_FTRACE */
108NOALIGN_ENTRY(ftrace_call_graph)
109	/* MS: jump over graph function - replaced from C code */
110	bri	end_graph_tracer
111#endif /* CONFIG_DYNAMIC_FTRACE */
112	addik	r5, r1, 120; /* MS: load parent addr */
113	addik	r6, r15, 0; /* MS: load current function addr */
114	bralid	r15, prepare_ftrace_return;
115	nop;
116	/* MS: graph was taken that's why - can jump over function trace */
117	brid	end;
118	nop;
119end_graph_tracer:
120#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
121#ifndef CONFIG_DYNAMIC_FTRACE
122	/* MS: test function trace if is taken or not */
123	lwi	r20, r0, ftrace_trace_function;
124	addik	r6, r0, ftrace_stub;
125	cmpu	r5, r20, r6; /* ftrace_trace_function != ftrace_stub */
126	beqid	r5, end; /* MS: not taken -> jump over */
127	nop;
128#else /* CONFIG_DYNAMIC_FTRACE */
129NOALIGN_ENTRY(ftrace_call)
130/* instruction for setup imm FUNC_part1, addik r20, r0, FUNC_part2 */
131	nop
132	nop
133#endif /* CONFIG_DYNAMIC_FTRACE */
134/* static normal trace */
135	lwi	r6, r1, 120; /* MS: load parent addr */
136	addik	r5, r15, -4; /* MS: load current function addr */
137	/* MS: here is dependency on previous code */
138	brald	r15, r20; /* MS: jump to ftrace handler */
139	nop;
140end:
141	lwi	r15, r1, 0;
142	RESTORE_REGS
143
144	rtsd	r15, 8; /* MS: jump back */
145	nop;
146
147#ifdef CONFIG_FUNCTION_GRAPH_TRACER
148ENTRY(return_to_handler)
149	nop; /* MS: just barrier for rtsd r15, 8 */
150	nop;
151	SAVE_REGS
152	swi	r15, r1, 0;
153
154	/* MS: find out returning address */
155	bralid	r15, ftrace_return_to_handler;
156	nop;
157
158	/* MS: return value from ftrace_return_to_handler is my returning addr
159	 * must be before restore regs because I have to restore r3 content */
160	addik	r15, r3, 0;
161	RESTORE_REGS
162
163	rtsd	r15, 8; /* MS: jump back */
164	nop;
165#endif	/* CONFIG_FUNCTION_TRACER */
166