arch/csky/abiv2/mcount.S

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
   3
   4 #include <linux/linkage.h>
   5 #include <asm/ftrace.h>
   6 #include <abi/entry.h>
   7 #include <asm/asm-offsets.h>
   8
   9 /*
  10  * csky-gcc with -pg will put the following asm after prologue:
  11  *      push    r15
  12  *      jsri    _mcount
  13  *
  14  * stack layout after mcount_enter in _mcount():
  15  *
  16  * current sp => 0:+-------+
  17  *                 | a0-a3 | -> must save all argument regs
  18  *             +16:+-------+
  19  *                 | lr    | -> _mcount lr (instrumente function's pc)
  20  *             +20:+-------+
  21  *                 | fp=r8 | -> instrumented function fp
  22  *             +24:+-------+
  23  *                 | plr   | -> instrumented function lr (parent's pc)
  24  *                 +-------+
  25  */
  26
  27 .macro mcount_enter
  28         subi    sp, 24
  29         stw     a0, (sp, 0)
  30         stw     a1, (sp, 4)
  31         stw     a2, (sp, 8)
  32         stw     a3, (sp, 12)
  33         stw     lr, (sp, 16)
  34         stw     r8, (sp, 20)
  35 .endm
  36
  37 .macro mcount_exit
  38         ldw     a0, (sp, 0)
  39         ldw     a1, (sp, 4)
  40         ldw     a2, (sp, 8)
  41         ldw     a3, (sp, 12)
  42         ldw     t1, (sp, 16)
  43         ldw     r8, (sp, 20)
  44         ldw     lr, (sp, 24)
  45         addi    sp, 28
  46         jmp     t1
  47 .endm
  48
  49 .macro mcount_enter_regs
  50         subi    sp, 8
  51         stw     lr, (sp, 0)
  52         stw     r8, (sp, 4)
  53         SAVE_REGS_FTRACE
  54 .endm
  55
  56 .macro mcount_exit_regs
  57         RESTORE_REGS_FTRACE
  58         ldw     t1, (sp, 0)
  59         ldw     r8, (sp, 4)
  60         ldw     lr, (sp, 8)
  61         addi    sp, 12
  62         jmp     t1
  63 .endm
  64
  65 .macro save_return_regs
  66         subi    sp, 16
  67         stw     a0, (sp, 0)
  68         stw     a1, (sp, 4)
  69         stw     a2, (sp, 8)
  70         stw     a3, (sp, 12)
  71 .endm
  72
  73 .macro restore_return_regs
  74         mov     lr, a0
  75         ldw     a0, (sp, 0)
  76         ldw     a1, (sp, 4)
  77         ldw     a2, (sp, 8)
  78         ldw     a3, (sp, 12)
  79         addi    sp, 16
  80 .endm
  81
  82 .macro nop32_stub
  83         nop32
  84         nop32
  85         nop32
  86 .endm
  87
  88 ENTRY(ftrace_stub)
  89         jmp     lr
  90 END(ftrace_stub)
  91
  92 #ifndef CONFIG_DYNAMIC_FTRACE
  93 ENTRY(_mcount)
  94         mcount_enter
  95
  96         /* r26 is link register, only used with jsri translation */
  97         lrw     r26, ftrace_trace_function
  98         ldw     r26, (r26, 0)
  99         lrw     a1, ftrace_stub
 100         cmpne   r26, a1
 101         bf      skip_ftrace
 102
 103         mov     a0, lr
 104         subi    a0, 4
 105         ldw     a1, (sp, 24)
 106         lrw     a2, function_trace_op
 107         ldw     a2, (a2, 0)
 108
 109         jsr     r26
 110
 111 #ifndef CONFIG_FUNCTION_GRAPH_TRACER
 112 skip_ftrace:
 113         mcount_exit
 114 #else
 115 skip_ftrace:
 116         lrw     a0, ftrace_graph_return
 117         ldw     a0, (a0, 0)
 118         lrw     a1, ftrace_stub
 119         cmpne   a0, a1
 120         bt      ftrace_graph_caller
 121
 122         lrw     a0, ftrace_graph_entry
 123         ldw     a0, (a0, 0)
 124         lrw     a1, ftrace_graph_entry_stub
 125         cmpne   a0, a1
 126         bt      ftrace_graph_caller
 127
 128         mcount_exit
 129 #endif
 130 END(_mcount)
 131 #else /* CONFIG_DYNAMIC_FTRACE */
 132 ENTRY(_mcount)
 133         mov     t1, lr
 134         ldw     lr, (sp, 0)
 135         addi    sp, 4
 136         jmp     t1
 137 ENDPROC(_mcount)
 138
 139 ENTRY(ftrace_caller)
 140         mcount_enter
 141
 142         ldw     a0, (sp, 16)
 143         subi    a0, 4
 144         ldw     a1, (sp, 24)
 145         lrw     a2, function_trace_op
 146         ldw     a2, (a2, 0)
 147
 148         nop
 149 GLOBAL(ftrace_call)
 150         nop32_stub
 151
 152 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 153         nop
 154 GLOBAL(ftrace_graph_call)
 155         nop32_stub
 156 #endif
 157
 158         mcount_exit
 159 ENDPROC(ftrace_caller)
 160 #endif /* CONFIG_DYNAMIC_FTRACE */
 161
 162 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 163 ENTRY(ftrace_graph_caller)
 164         mov     a0, sp
 165         addi    a0, 24
 166         ldw     a1, (sp, 16)
 167         subi    a1, 4
 168         mov     a2, r8
 169         lrw     r26, prepare_ftrace_return
 170         jsr     r26
 171         mcount_exit
 172 END(ftrace_graph_caller)
 173
 174 ENTRY(return_to_handler)
 175         save_return_regs
 176         mov     a0, r8
 177         jsri    ftrace_return_to_handler
 178         restore_return_regs
 179         jmp     lr
 180 END(return_to_handler)
 181 #endif
 182
 183 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 184 ENTRY(ftrace_regs_caller)
 185         mcount_enter_regs
 186
 187         lrw     t1, PT_FRAME_SIZE
 188         add     t1, sp
 189
 190         ldw     a0, (t1, 0)
 191         subi    a0, 4
 192         ldw     a1, (t1, 8)
 193         lrw     a2, function_trace_op
 194         ldw     a2, (a2, 0)
 195         mov     a3, sp
 196
 197         nop
 198 GLOBAL(ftrace_regs_call)
 199         nop32_stub
 200
 201 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 202         nop
 203 GLOBAL(ftrace_graph_regs_call)
 204         nop32_stub
 205 #endif
 206
 207         mcount_exit_regs
 208 ENDPROC(ftrace_regs_caller)
 209 #endif /* CONFIG_DYNAMIC_FTRACE */