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 * Copyright (C) 2010 DSLab, Lanzhou University, China
 10 * Author: Wu Zhangjin <wuzhangjin@gmail.com>
 11 */
 12
 13#include <asm/regdef.h>
 14#include <asm/stackframe.h>
 15#include <asm/ftrace.h>
 16
 17	.text
 18	.set noreorder
 19	.set noat
 20
 21	.macro MCOUNT_SAVE_REGS
 22	PTR_SUBU	sp, PT_SIZE
 23	PTR_S	ra, PT_R31(sp)
 24	PTR_S	AT, PT_R1(sp)
 25	PTR_S	a0, PT_R4(sp)
 26	PTR_S	a1, PT_R5(sp)
 27	PTR_S	a2, PT_R6(sp)
 28	PTR_S	a3, PT_R7(sp)
 29#ifdef CONFIG_64BIT
 30	PTR_S	a4, PT_R8(sp)
 31	PTR_S	a5, PT_R9(sp)
 32	PTR_S	a6, PT_R10(sp)
 33	PTR_S	a7, PT_R11(sp)
 34#endif
 35	.endm
 36
 37	.macro MCOUNT_RESTORE_REGS
 38	PTR_L	ra, PT_R31(sp)
 39	PTR_L	AT, PT_R1(sp)
 40	PTR_L	a0, PT_R4(sp)
 41	PTR_L	a1, PT_R5(sp)
 42	PTR_L	a2, PT_R6(sp)
 43	PTR_L	a3, PT_R7(sp)
 44#ifdef CONFIG_64BIT
 45	PTR_L	a4, PT_R8(sp)
 46	PTR_L	a5, PT_R9(sp)
 47	PTR_L	a6, PT_R10(sp)
 48	PTR_L	a7, PT_R11(sp)
 49	PTR_ADDIU	sp, PT_SIZE
 50#else
 51	PTR_ADDIU	sp, (PT_SIZE + 8)
 52#endif
 53.endm
 54
 55	.macro RETURN_BACK
 56	jr ra
 57	 move ra, AT
 58	.endm
 59
 60/*
 61 * The -mmcount-ra-address option of gcc 4.5 uses register $12 to pass
 62 * the location of the parent's return address.
 63 */
 64#define MCOUNT_RA_ADDRESS_REG	$12
 65
 66#ifdef CONFIG_DYNAMIC_FTRACE
 67
 68NESTED(ftrace_caller, PT_SIZE, ra)
 69	.globl _mcount
 70_mcount:
 71	b	ftrace_stub
 72	 nop
 73	lw	t1, function_trace_stop
 74	bnez	t1, ftrace_stub
 75	 nop
 76
 77	MCOUNT_SAVE_REGS
 78#ifdef KBUILD_MCOUNT_RA_ADDRESS
 79	PTR_S	MCOUNT_RA_ADDRESS_REG, PT_R12(sp)
 80#endif
 81
 82	move	a0, ra		/* arg1: self return address */
 83	.globl ftrace_call
 84ftrace_call:
 85	nop	/* a placeholder for the call to a real tracing function */
 86	 move	a1, AT		/* arg2: parent's return address */
 87
 88#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 89	.globl ftrace_graph_call
 90ftrace_graph_call:
 91	nop
 92	 nop
 93#endif
 94
 95	MCOUNT_RESTORE_REGS
 96	.globl ftrace_stub
 97ftrace_stub:
 98	RETURN_BACK
 99	END(ftrace_caller)
100
101#else	/* ! CONFIG_DYNAMIC_FTRACE */
102
103NESTED(_mcount, PT_SIZE, ra)
104	lw	t1, function_trace_stop
105	bnez	t1, ftrace_stub
106	 nop
107	PTR_LA	t1, ftrace_stub
108	PTR_L	t2, ftrace_trace_function /* Prepare t2 for (1) */
109	bne	t1, t2, static_trace
110	 nop
111
112#ifdef	CONFIG_FUNCTION_GRAPH_TRACER
113	PTR_L	t3, ftrace_graph_return
114	bne	t1, t3, ftrace_graph_caller
115	 nop
116	PTR_LA	t1, ftrace_graph_entry_stub
117	PTR_L	t3, ftrace_graph_entry
118	bne	t1, t3, ftrace_graph_caller
119	 nop
120#endif
121	b	ftrace_stub
122	 nop
123
124static_trace:
125	MCOUNT_SAVE_REGS
126
127	move	a0, ra		/* arg1: self return address */
128	jalr	t2		/* (1) call *ftrace_trace_function */
129	 move	a1, AT		/* arg2: parent's return address */
130
131	MCOUNT_RESTORE_REGS
132	.globl ftrace_stub
133ftrace_stub:
134	RETURN_BACK
135	END(_mcount)
136
137#endif	/* ! CONFIG_DYNAMIC_FTRACE */
138
139#ifdef CONFIG_FUNCTION_GRAPH_TRACER
140
141NESTED(ftrace_graph_caller, PT_SIZE, ra)
142#ifndef CONFIG_DYNAMIC_FTRACE
143	MCOUNT_SAVE_REGS
144#endif
145
146	/* arg1: Get the location of the parent's return address */
147#ifdef KBUILD_MCOUNT_RA_ADDRESS
148#ifdef CONFIG_DYNAMIC_FTRACE
149	PTR_L	a0, PT_R12(sp)
150#else
151	move	a0, MCOUNT_RA_ADDRESS_REG
152#endif
153	bnez	a0, 1f	/* non-leaf func: stored in MCOUNT_RA_ADDRESS_REG */
154	 nop
155#endif
156	PTR_LA	a0, PT_R1(sp)	/* leaf func: the location in current stack */
1571:
158
159	/* arg2: Get self return address */
160#ifdef CONFIG_DYNAMIC_FTRACE
161	PTR_L	a1, PT_R31(sp)
162#else
163	move	a1, ra
164#endif
165
166	/* arg3: Get frame pointer of current stack */
167#ifdef CONFIG_FRAME_POINTER
168	move	a2, fp
169#else /* ! CONFIG_FRAME_POINTER */
170#ifdef CONFIG_64BIT
171	PTR_LA	a2, PT_SIZE(sp)
172#else
173	PTR_LA	a2, (PT_SIZE+8)(sp)
174#endif
175#endif
176
177	jal	prepare_ftrace_return
178	 nop
179	MCOUNT_RESTORE_REGS
180	RETURN_BACK
181	END(ftrace_graph_caller)
182
183	.align	2
184	.globl	return_to_handler
185return_to_handler:
186	PTR_SUBU	sp, PT_SIZE
187	PTR_S	v0, PT_R2(sp)
188
189	jal	ftrace_return_to_handler
190	 PTR_S	v1, PT_R3(sp)
191
192	/* restore the real parent address: v0 -> ra */
193	move	ra, v0
194
195	PTR_L	v0, PT_R2(sp)
196	PTR_L	v1, PT_R3(sp)
197	jr	ra
198	 PTR_ADDIU	sp, PT_SIZE
199#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
200
201	.set at
202	.set reorder