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 203