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 MCOUNT_SAVE_REGS 78#ifdef KBUILD_MCOUNT_RA_ADDRESS 79 PTR_S MCOUNT_RA_ADDRESS_REG, PT_R12(sp) 80#endif 81 82 PTR_SUBU a0, ra, 8 /* arg1: self 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 PTR_LA t1, ftrace_stub 105 PTR_L t2, ftrace_trace_function /* Prepare t2 for (1) */ 106 bne t1, t2, static_trace 107 nop 108 109#ifdef CONFIG_FUNCTION_GRAPH_TRACER 110 PTR_L t3, ftrace_graph_return 111 bne t1, t3, ftrace_graph_caller 112 nop 113 PTR_LA t1, ftrace_graph_entry_stub 114 PTR_L t3, ftrace_graph_entry 115 bne t1, t3, ftrace_graph_caller 116 nop 117#endif 118 b ftrace_stub 119 nop 120 121static_trace: 122 MCOUNT_SAVE_REGS 123 124 move a0, ra /* arg1: self return address */ 125 jalr t2 /* (1) call *ftrace_trace_function */ 126 move a1, AT /* arg2: parent's return address */ 127 128 MCOUNT_RESTORE_REGS 129 .globl ftrace_stub 130ftrace_stub: 131 RETURN_BACK 132 END(_mcount) 133 134#endif /* ! CONFIG_DYNAMIC_FTRACE */ 135 136#ifdef CONFIG_FUNCTION_GRAPH_TRACER 137 138NESTED(ftrace_graph_caller, PT_SIZE, ra) 139#ifndef CONFIG_DYNAMIC_FTRACE 140 MCOUNT_SAVE_REGS 141#endif 142 143 /* arg1: Get the location of the parent's return address */ 144#ifdef KBUILD_MCOUNT_RA_ADDRESS 145#ifdef CONFIG_DYNAMIC_FTRACE 146 PTR_L a0, PT_R12(sp) 147#else 148 move a0, MCOUNT_RA_ADDRESS_REG 149#endif 150 bnez a0, 1f /* non-leaf func: stored in MCOUNT_RA_ADDRESS_REG */ 151 nop 152#endif 153 PTR_LA a0, PT_R1(sp) /* leaf func: the location in current stack */ 1541: 155 156 /* arg2: Get self return address */ 157#ifdef CONFIG_DYNAMIC_FTRACE 158 PTR_L a1, PT_R31(sp) 159#else 160 move a1, ra 161#endif 162 163 /* arg3: Get frame pointer of current stack */ 164#ifdef CONFIG_64BIT 165 PTR_LA a2, PT_SIZE(sp) 166#else 167 PTR_LA a2, (PT_SIZE+8)(sp) 168#endif 169 170 jal prepare_ftrace_return 171 nop 172 MCOUNT_RESTORE_REGS 173 RETURN_BACK 174 END(ftrace_graph_caller) 175 176 .align 2 177 .globl return_to_handler 178return_to_handler: 179 PTR_SUBU sp, PT_SIZE 180 PTR_S v0, PT_R2(sp) 181 182 jal ftrace_return_to_handler 183 PTR_S v1, PT_R3(sp) 184 185 /* restore the real parent address: v0 -> ra */ 186 move ra, v0 187 188 PTR_L v0, PT_R2(sp) 189 PTR_L v1, PT_R3(sp) 190 jr ra 191 PTR_ADDIU sp, PT_SIZE 192#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 193 194 .set at 195 .set reorder 196