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  * Author: Wu Zhangjin <wuzj@lemote.com>
  10  */
  11
  12 #include <asm/regdef.h>
  13 #include <asm/stackframe.h>
  14 #include <asm/ftrace.h>
  15
  16         .text
  17         .set noreorder
  18         .set noat
  19
  20         .macro MCOUNT_SAVE_REGS
  21         PTR_SUBU        sp, PT_SIZE
  22         PTR_S   ra, PT_R31(sp)
  23         PTR_S   AT, PT_R1(sp)
  24         PTR_S   a0, PT_R4(sp)
  25         PTR_S   a1, PT_R5(sp)
  26         PTR_S   a2, PT_R6(sp)
  27         PTR_S   a3, PT_R7(sp)
  28 #ifdef CONFIG_64BIT
  29         PTR_S   a4, PT_R8(sp)
  30         PTR_S   a5, PT_R9(sp)
  31         PTR_S   a6, PT_R10(sp)
  32         PTR_S   a7, PT_R11(sp)
  33 #endif
  34         .endm
  35
  36         .macro MCOUNT_RESTORE_REGS
  37         PTR_L   ra, PT_R31(sp)
  38         PTR_L   AT, PT_R1(sp)
  39         PTR_L   a0, PT_R4(sp)
  40         PTR_L   a1, PT_R5(sp)
  41         PTR_L   a2, PT_R6(sp)
  42         PTR_L   a3, PT_R7(sp)
  43 #ifdef CONFIG_64BIT
  44         PTR_L   a4, PT_R8(sp)
  45         PTR_L   a5, PT_R9(sp)
  46         PTR_L   a6, PT_R10(sp)
  47         PTR_L   a7, PT_R11(sp)
  48 #endif
  49 #ifdef CONFIG_64BIT
  50         PTR_ADDIU       sp, PT_SIZE
  51 #else
  52         PTR_ADDIU       sp, (PT_SIZE + 8)
  53 #endif
  54 .endm
  55
  56         .macro RETURN_BACK
  57         jr ra
  58          move ra, AT
  59         .endm
  60
  61 #ifdef CONFIG_DYNAMIC_FTRACE
  62
  63 NESTED(ftrace_caller, PT_SIZE, ra)
  64         .globl _mcount
  65 _mcount:
  66         b       ftrace_stub
  67          nop
  68         lw      t1, function_trace_stop
  69         bnez    t1, ftrace_stub
  70          nop
  71
  72         MCOUNT_SAVE_REGS
  73 #ifdef KBUILD_MCOUNT_RA_ADDRESS
  74         PTR_S   t0, PT_R12(sp)  /* t0 saved the location of the return address(at) by -mmcount-ra-address */
  75 #endif
  76
  77         move    a0, ra          /* arg1: next ip, selfaddr */
  78         .globl ftrace_call
  79 ftrace_call:
  80         nop     /* a placeholder for the call to a real tracing function */
  81          move   a1, AT          /* arg2: the caller's next ip, parent */
  82
  83 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  84         .globl ftrace_graph_call
  85 ftrace_graph_call:
  86         nop
  87          nop
  88 #endif
  89
  90         MCOUNT_RESTORE_REGS
  91         .globl ftrace_stub
  92 ftrace_stub:
  93         RETURN_BACK
  94         END(ftrace_caller)
  95
  96 #else   /* ! CONFIG_DYNAMIC_FTRACE */
  97
  98 NESTED(_mcount, PT_SIZE, ra)
  99         lw      t1, function_trace_stop
 100         bnez    t1, ftrace_stub
 101          nop
 102         PTR_LA  t1, ftrace_stub
 103         PTR_L   t2, ftrace_trace_function /* Prepare t2 for (1) */
 104         bne     t1, t2, static_trace
 105          nop
 106
 107 #ifdef  CONFIG_FUNCTION_GRAPH_TRACER
 108         PTR_L   t3, ftrace_graph_return
 109         bne     t1, t3, ftrace_graph_caller
 110          nop
 111         PTR_LA  t1, ftrace_graph_entry_stub
 112         PTR_L   t3, ftrace_graph_entry
 113         bne     t1, t3, ftrace_graph_caller
 114          nop
 115 #endif
 116         b       ftrace_stub
 117          nop
 118
 119 static_trace:
 120         MCOUNT_SAVE_REGS
 121
 122         move    a0, ra          /* arg1: next ip, selfaddr */
 123         jalr    t2              /* (1) call *ftrace_trace_function */
 124          move   a1, AT          /* arg2: the caller's next ip, parent */
 125
 126         MCOUNT_RESTORE_REGS
 127         .globl ftrace_stub
 128 ftrace_stub:
 129         RETURN_BACK
 130         END(_mcount)
 131
 132 #endif  /* ! CONFIG_DYNAMIC_FTRACE */
 133
 134 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 135
 136 NESTED(ftrace_graph_caller, PT_SIZE, ra)
 137 #ifdef CONFIG_DYNAMIC_FTRACE
 138         PTR_L   a1, PT_R31(sp)  /* load the original ra from the stack */
 139 #ifdef KBUILD_MCOUNT_RA_ADDRESS
 140         PTR_L   t0, PT_R12(sp)  /* load the original t0 from the stack */
 141 #endif
 142 #else
 143         MCOUNT_SAVE_REGS
 144         move    a1, ra          /* arg2: next ip, selfaddr */
 145 #endif
 146
 147 #ifdef KBUILD_MCOUNT_RA_ADDRESS
 148         bnez    t0, 1f          /* non-leaf func: t0 saved the location of the return address */
 149          nop
 150         PTR_LA  t0, PT_R1(sp)   /* leaf func: get the location of at(old ra) from our own stack */
 151 1:      move    a0, t0          /* arg1: the location of the return address */
 152 #else
 153         PTR_LA  a0, PT_R1(sp)   /* arg1: &AT -> a0 */
 154 #endif
 155         jal     prepare_ftrace_return
 156 #ifdef CONFIG_FRAME_POINTER
 157          move   a2, fp          /* arg3: frame pointer */
 158 #else
 159 #ifdef CONFIG_64BIT
 160          PTR_LA a2, PT_SIZE(sp)
 161 #else
 162          PTR_LA a2, (PT_SIZE+8)(sp)
 163 #endif
 164 #endif
 165
 166         MCOUNT_RESTORE_REGS
 167         RETURN_BACK
 168         END(ftrace_graph_caller)
 169
 170         .align  2
 171         .globl  return_to_handler
 172 return_to_handler:
 173         PTR_SUBU        sp, PT_SIZE
 174         PTR_S   v0, PT_R2(sp)
 175
 176         jal     ftrace_return_to_handler
 177          PTR_S  v1, PT_R3(sp)
 178
 179         /* restore the real parent address: v0 -> ra */
 180         move    ra, v0
 181
 182         PTR_L   v0, PT_R2(sp)
 183         PTR_L   v1, PT_R3(sp)
 184         jr      ra
 185          PTR_ADDIU      sp, PT_SIZE
 186 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 187
 188         .set at
 189         .set reorder