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#endif 50 PTR_ADDIU sp, PT_SIZE 51 .endm 52 53 .macro RETURN_BACK 54 jr ra 55 move ra, AT 56 .endm 57 58/* 59 * The -mmcount-ra-address option of gcc 4.5 uses register $12 to pass 60 * the location of the parent's return address. 61 */ 62#define MCOUNT_RA_ADDRESS_REG $12 63 64#ifdef CONFIG_DYNAMIC_FTRACE 65 66NESTED(ftrace_caller, PT_SIZE, ra) 67 .globl _mcount 68_mcount: 69 b ftrace_stub 70#ifdef CONFIG_32BIT 71 addiu sp,sp,8 72#else 73 nop 74#endif 75 76 /* When tracing is activated, it calls ftrace_caller+8 (aka here) */ 77 lw t1, function_trace_stop 78 bnez t1, ftrace_stub 79 nop 80 81 MCOUNT_SAVE_REGS 82#ifdef KBUILD_MCOUNT_RA_ADDRESS 83 PTR_S MCOUNT_RA_ADDRESS_REG, PT_R12(sp) 84#endif 85 86 move a0, ra /* arg1: self return address */ 87 .globl ftrace_call 88ftrace_call: 89 nop /* a placeholder for the call to a real tracing function */ 90 move a1, AT /* arg2: parent's return address */ 91 92#ifdef CONFIG_FUNCTION_GRAPH_TRACER 93 .globl ftrace_graph_call 94ftrace_graph_call: 95 nop 96 nop 97#endif 98 99 MCOUNT_RESTORE_REGS 100 .globl ftrace_stub 101ftrace_stub: 102 RETURN_BACK 103 END(ftrace_caller) 104 105#else /* ! CONFIG_DYNAMIC_FTRACE */ 106 107NESTED(_mcount, PT_SIZE, ra) 108 lw t1, function_trace_stop 109 bnez t1, ftrace_stub 110 nop 111 PTR_LA t1, ftrace_stub 112 PTR_L t2, ftrace_trace_function /* Prepare t2 for (1) */ 113 bne t1, t2, static_trace 114 nop 115 116#ifdef CONFIG_FUNCTION_GRAPH_TRACER 117 PTR_L t3, ftrace_graph_return 118 bne t1, t3, ftrace_graph_caller 119 nop 120 PTR_LA t1, ftrace_graph_entry_stub 121 PTR_L t3, ftrace_graph_entry 122 bne t1, t3, ftrace_graph_caller 123 nop 124#endif 125 b ftrace_stub 126 nop 127 128static_trace: 129 MCOUNT_SAVE_REGS 130 131 move a0, ra /* arg1: self return address */ 132 jalr t2 /* (1) call *ftrace_trace_function */ 133 move a1, AT /* arg2: parent's return address */ 134 135 MCOUNT_RESTORE_REGS 136 .globl ftrace_stub 137ftrace_stub: 138 RETURN_BACK 139 END(_mcount) 140 141#endif /* ! CONFIG_DYNAMIC_FTRACE */ 142 143#ifdef CONFIG_FUNCTION_GRAPH_TRACER 144 145NESTED(ftrace_graph_caller, PT_SIZE, ra) 146#ifndef CONFIG_DYNAMIC_FTRACE 147 MCOUNT_SAVE_REGS 148#endif 149 150 /* arg1: Get the location of the parent's return address */ 151#ifdef KBUILD_MCOUNT_RA_ADDRESS 152#ifdef CONFIG_DYNAMIC_FTRACE 153 PTR_L a0, PT_R12(sp) 154#else 155 move a0, MCOUNT_RA_ADDRESS_REG 156#endif 157 bnez a0, 1f /* non-leaf func: stored in MCOUNT_RA_ADDRESS_REG */ 158 nop 159#endif 160 PTR_LA a0, PT_R1(sp) /* leaf func: the location in current stack */ 1611: 162 163 /* arg2: Get self return address */ 164#ifdef CONFIG_DYNAMIC_FTRACE 165 PTR_L a1, PT_R31(sp) 166#else 167 move a1, ra 168#endif 169 170 /* arg3: Get frame pointer of current stack */ 171#ifdef CONFIG_64BIT 172 PTR_LA a2, PT_SIZE(sp) 173#else 174 PTR_LA a2, (PT_SIZE+8)(sp) 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 203