root/arch/mips/kernel/mcount.S

   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/export.h>
  14 #include <asm/regdef.h>
  15 #include <asm/stackframe.h>
  16 #include <asm/ftrace.h>
  17 
  18         .text
  19         .set noreorder
  20         .set noat
  21 
  22         .macro MCOUNT_SAVE_REGS
  23         PTR_SUBU        sp, PT_SIZE
  24         PTR_S   ra, PT_R31(sp)
  25         PTR_S   AT, PT_R1(sp)
  26         PTR_S   a0, PT_R4(sp)
  27         PTR_S   a1, PT_R5(sp)
  28         PTR_S   a2, PT_R6(sp)
  29         PTR_S   a3, PT_R7(sp)
  30 #ifdef CONFIG_64BIT
  31         PTR_S   a4, PT_R8(sp)
  32         PTR_S   a5, PT_R9(sp)
  33         PTR_S   a6, PT_R10(sp)
  34         PTR_S   a7, PT_R11(sp)
  35 #endif
  36         .endm
  37 
  38         .macro MCOUNT_RESTORE_REGS
  39         PTR_L   ra, PT_R31(sp)
  40         PTR_L   AT, PT_R1(sp)
  41         PTR_L   a0, PT_R4(sp)
  42         PTR_L   a1, PT_R5(sp)
  43         PTR_L   a2, PT_R6(sp)
  44         PTR_L   a3, PT_R7(sp)
  45 #ifdef CONFIG_64BIT
  46         PTR_L   a4, PT_R8(sp)
  47         PTR_L   a5, PT_R9(sp)
  48         PTR_L   a6, PT_R10(sp)
  49         PTR_L   a7, PT_R11(sp)
  50 #endif
  51         PTR_ADDIU       sp, PT_SIZE
  52         .endm
  53 
  54         .macro RETURN_BACK
  55         jr ra
  56          move ra, AT
  57         .endm
  58 
  59 /*
  60  * The -mmcount-ra-address option of gcc 4.5 uses register $12 to pass
  61  * the location of the parent's return address.
  62  */
  63 #define MCOUNT_RA_ADDRESS_REG   $12
  64 
  65 #ifdef CONFIG_DYNAMIC_FTRACE
  66 
  67 NESTED(ftrace_caller, PT_SIZE, ra)
  68         .globl _mcount
  69 _mcount:
  70 EXPORT_SYMBOL(_mcount)
  71         b       ftrace_stub
  72 #ifdef CONFIG_32BIT
  73          addiu sp,sp,8
  74 #else
  75          nop
  76 #endif
  77 
  78         /* When tracing is activated, it calls ftrace_caller+8 (aka here) */
  79         MCOUNT_SAVE_REGS
  80 #ifdef KBUILD_MCOUNT_RA_ADDRESS
  81         PTR_S   MCOUNT_RA_ADDRESS_REG, PT_R12(sp)
  82 #endif
  83 
  84         PTR_SUBU a0, ra, 8      /* arg1: self address */
  85         PTR_LA   t1, _stext
  86         sltu     t2, a0, t1     /* t2 = (a0 < _stext) */
  87         PTR_LA   t1, _etext
  88         sltu     t3, t1, a0     /* t3 = (a0 > _etext) */
  89         or       t1, t2, t3
  90         beqz     t1, ftrace_call
  91          nop
  92 #if defined(KBUILD_MCOUNT_RA_ADDRESS) && defined(CONFIG_32BIT)
  93         PTR_SUBU a0, a0, 16     /* arg1: adjust to module's recorded callsite */
  94 #else
  95         PTR_SUBU a0, a0, 12
  96 #endif
  97 
  98         .globl ftrace_call
  99 ftrace_call:
 100         nop     /* a placeholder for the call to a real tracing function */
 101          move   a1, AT          /* arg2: parent's return address */
 102 
 103 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 104         .globl ftrace_graph_call
 105 ftrace_graph_call:
 106         nop
 107          nop
 108 #endif
 109 
 110         MCOUNT_RESTORE_REGS
 111         .globl ftrace_stub
 112 ftrace_stub:
 113         RETURN_BACK
 114         END(ftrace_caller)
 115 
 116 #else   /* ! CONFIG_DYNAMIC_FTRACE */
 117 
 118 NESTED(_mcount, PT_SIZE, ra)
 119 EXPORT_SYMBOL(_mcount)
 120         PTR_LA  t1, ftrace_stub
 121         PTR_L   t2, ftrace_trace_function /* Prepare t2 for (1) */
 122         beq     t1, t2, fgraph_trace
 123          nop
 124 
 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 
 133 fgraph_trace:
 134 #ifdef  CONFIG_FUNCTION_GRAPH_TRACER
 135         PTR_LA  t1, ftrace_stub
 136         PTR_L   t3, ftrace_graph_return
 137         bne     t1, t3, ftrace_graph_caller
 138          nop
 139         PTR_LA  t1, ftrace_graph_entry_stub
 140         PTR_L   t3, ftrace_graph_entry
 141         bne     t1, t3, ftrace_graph_caller
 142          nop
 143 #endif
 144 
 145 #ifdef CONFIG_32BIT
 146         addiu sp, sp, 8
 147 #endif
 148 
 149         .globl ftrace_stub
 150 ftrace_stub:
 151         RETURN_BACK
 152         END(_mcount)
 153 
 154 #endif  /* ! CONFIG_DYNAMIC_FTRACE */
 155 
 156 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 157 
 158 NESTED(ftrace_graph_caller, PT_SIZE, ra)
 159 #ifndef CONFIG_DYNAMIC_FTRACE
 160         MCOUNT_SAVE_REGS
 161 #endif
 162 
 163         /* arg1: Get the location of the parent's return address */
 164 #ifdef KBUILD_MCOUNT_RA_ADDRESS
 165 #ifdef CONFIG_DYNAMIC_FTRACE
 166         PTR_L   a0, PT_R12(sp)
 167 #else
 168         move    a0, MCOUNT_RA_ADDRESS_REG
 169 #endif
 170         bnez    a0, 1f  /* non-leaf func: stored in MCOUNT_RA_ADDRESS_REG */
 171          nop
 172 #endif
 173         PTR_LA  a0, PT_R1(sp)   /* leaf func: the location in current stack */
 174 1:
 175 
 176         /* arg2: Get self return address */
 177 #ifdef CONFIG_DYNAMIC_FTRACE
 178         PTR_L   a1, PT_R31(sp)
 179 #else
 180         move    a1, ra
 181 #endif
 182 
 183         /* arg3: Get frame pointer of current stack */
 184 #ifdef CONFIG_64BIT
 185         PTR_LA  a2, PT_SIZE(sp)
 186 #else
 187         PTR_LA  a2, (PT_SIZE+8)(sp)
 188 #endif
 189 
 190         jal     prepare_ftrace_return
 191          nop
 192         MCOUNT_RESTORE_REGS
 193 #ifndef CONFIG_DYNAMIC_FTRACE
 194 #ifdef CONFIG_32BIT
 195         addiu sp, sp, 8
 196 #endif
 197 #endif
 198         RETURN_BACK
 199         END(ftrace_graph_caller)
 200 
 201         .align  2
 202         .globl  return_to_handler
 203 return_to_handler:
 204         PTR_SUBU        sp, PT_SIZE
 205         PTR_S   v0, PT_R2(sp)
 206 
 207         jal     ftrace_return_to_handler
 208          PTR_S  v1, PT_R3(sp)
 209 
 210         /* restore the real parent address: v0 -> ra */
 211         move    ra, v0
 212 
 213         PTR_L   v0, PT_R2(sp)
 214         PTR_L   v1, PT_R3(sp)
 215         jr      ra
 216          PTR_ADDIU      sp, PT_SIZE
 217 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 218 
 219         .set at
 220         .set reorder