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/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 #else
  50         PTR_ADDIU       sp, PT_SIZE
  51 #endif
  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         b       ftrace_stub
  71         addiu sp,sp,8
  72
  73         /* When tracing is activated, it calls ftrace_caller+8 (aka here) */
  74         lw      t1, function_trace_stop
  75         bnez    t1, ftrace_stub
  76          nop
  77
  78         MCOUNT_SAVE_REGS
  79 #ifdef KBUILD_MCOUNT_RA_ADDRESS
  80         PTR_S   MCOUNT_RA_ADDRESS_REG, PT_R12(sp)
  81 #endif
  82
  83         move    a0, ra          /* arg1: self return address */
  84         .globl ftrace_call
  85 ftrace_call:
  86         nop     /* a placeholder for the call to a real tracing function */
  87          move   a1, AT          /* arg2: parent's return address */
  88
  89 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  90         .globl ftrace_graph_call
  91 ftrace_graph_call:
  92         nop
  93          nop
  94 #endif
  95
  96         MCOUNT_RESTORE_REGS
  97         .globl ftrace_stub
  98 ftrace_stub:
  99         RETURN_BACK
 100         END(ftrace_caller)
 101
 102 #else   /* ! CONFIG_DYNAMIC_FTRACE */
 103
 104 NESTED(_mcount, PT_SIZE, ra)
 105         lw      t1, function_trace_stop
 106         bnez    t1, ftrace_stub
 107          nop
 108         PTR_LA  t1, ftrace_stub
 109         PTR_L   t2, ftrace_trace_function /* Prepare t2 for (1) */
 110         bne     t1, t2, static_trace
 111          nop
 112
 113 #ifdef  CONFIG_FUNCTION_GRAPH_TRACER
 114         PTR_L   t3, ftrace_graph_return
 115         bne     t1, t3, ftrace_graph_caller
 116          nop
 117         PTR_LA  t1, ftrace_graph_entry_stub
 118         PTR_L   t3, ftrace_graph_entry
 119         bne     t1, t3, ftrace_graph_caller
 120          nop
 121 #endif
 122         b       ftrace_stub
 123          nop
 124
 125 static_trace:
 126         MCOUNT_SAVE_REGS
 127
 128         move    a0, ra          /* arg1: self return address */
 129         jalr    t2              /* (1) call *ftrace_trace_function */
 130          move   a1, AT          /* arg2: parent's return address */
 131
 132         MCOUNT_RESTORE_REGS
 133         .globl ftrace_stub
 134 ftrace_stub:
 135         RETURN_BACK
 136         END(_mcount)
 137
 138 #endif  /* ! CONFIG_DYNAMIC_FTRACE */
 139
 140 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 141
 142 NESTED(ftrace_graph_caller, PT_SIZE, ra)
 143 #ifndef CONFIG_DYNAMIC_FTRACE
 144         MCOUNT_SAVE_REGS
 145 #endif
 146
 147         /* arg1: Get the location of the parent's return address */
 148 #ifdef KBUILD_MCOUNT_RA_ADDRESS
 149 #ifdef CONFIG_DYNAMIC_FTRACE
 150         PTR_L   a0, PT_R12(sp)
 151 #else
 152         move    a0, MCOUNT_RA_ADDRESS_REG
 153 #endif
 154         bnez    a0, 1f  /* non-leaf func: stored in MCOUNT_RA_ADDRESS_REG */
 155          nop
 156 #endif
 157         PTR_LA  a0, PT_R1(sp)   /* leaf func: the location in current stack */
 158 1:
 159
 160         /* arg2: Get self return address */
 161 #ifdef CONFIG_DYNAMIC_FTRACE
 162         PTR_L   a1, PT_R31(sp)
 163 #else
 164         move    a1, ra
 165 #endif
 166
 167         /* arg3: Get frame pointer of current stack */
 168 #ifdef CONFIG_FRAME_POINTER
 169         move    a2, fp
 170 #else /* ! CONFIG_FRAME_POINTER */
 171 #ifdef CONFIG_64BIT
 172         PTR_LA  a2, PT_SIZE(sp)
 173 #else
 174         PTR_LA  a2, (PT_SIZE+8)(sp)
 175 #endif
 176 #endif
 177
 178         jal     prepare_ftrace_return
 179          nop
 180         MCOUNT_RESTORE_REGS
 181         RETURN_BACK
 182         END(ftrace_graph_caller)
 183
 184         .align  2
 185         .globl  return_to_handler
 186 return_to_handler:
 187         PTR_SUBU        sp, PT_SIZE
 188         PTR_S   v0, PT_R2(sp)
 189
 190         jal     ftrace_return_to_handler
 191          PTR_S  v1, PT_R3(sp)
 192
 193         /* restore the real parent address: v0 -> ra */
 194         move    ra, v0
 195
 196         PTR_L   v0, PT_R2(sp)
 197         PTR_L   v1, PT_R3(sp)
 198         jr      ra
 199          PTR_ADDIU      sp, PT_SIZE
 200 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 201
 202         .set at
 203         .set reorder