arch/powerpc/kernel/trace/ftrace_64.S

   1 /*
   2  * Split from entry_64.S
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version
   7  * 2 of the License, or (at your option) any later version.
   8  */
   9
  10 #include <linux/magic.h>
  11 #include <asm/ppc_asm.h>
  12 #include <asm/asm-offsets.h>
  13 #include <asm/ftrace.h>
  14 #include <asm/ppc-opcode.h>
  15 #include <asm/export.h>
  16
  17 .pushsection ".tramp.ftrace.text","aw",@progbits;
  18 .globl ftrace_tramp_text
  19 ftrace_tramp_text:
  20         .space 64
  21 .popsection
  22
  23 .pushsection ".tramp.ftrace.init","aw",@progbits;
  24 .globl ftrace_tramp_init
  25 ftrace_tramp_init:
  26         .space 64
  27 .popsection
  28
  29 _GLOBAL(mcount)
  30 _GLOBAL(_mcount)
  31 EXPORT_SYMBOL(_mcount)
  32         mflr    r12
  33         mtctr   r12
  34         mtlr    r0
  35         bctr
  36
  37 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  38 _GLOBAL(return_to_handler)
  39         /* need to save return values */
  40         std     r4,  -32(r1)
  41         std     r3,  -24(r1)
  42         /* save TOC */
  43         std     r2,  -16(r1)
  44         std     r31, -8(r1)
  45         mr      r31, r1
  46         stdu    r1, -112(r1)
  47
  48         /*
  49          * We might be called from a module.
  50          * Switch to our TOC to run inside the core kernel.
  51          */
  52         ld      r2, PACATOC(r13)
  53
  54         bl      ftrace_return_to_handler
  55         nop
  56
  57         /* return value has real return address */
  58         mtlr    r3
  59
  60         ld      r1, 0(r1)
  61         ld      r4,  -32(r1)
  62         ld      r3,  -24(r1)
  63         ld      r2,  -16(r1)
  64         ld      r31, -8(r1)
  65
  66         /* Jump back to real return address */
  67         blr
  68 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */