arch/xtensa/kernel/mcount.S

   1 /*
   2  * arch/xtensa/kernel/mcount.S
   3  *
   4  * Xtensa specific mcount support
   5  *
   6  * This file is subject to the terms and conditions of the GNU General Public
   7  * License.  See the file "COPYING" in the main directory of this archive
   8  * for more details.
   9  *
  10  * Copyright (C) 2013 Tensilica Inc.
  11  */
  12
  13 #include <linux/linkage.h>
  14 #include <asm/ftrace.h>
  15
  16 /*
  17  * Entry condition:
  18  *
  19  *   a2:        a0 of the caller
  20  */
  21
  22 ENTRY(_mcount)
  23
  24         entry   a1, 16
  25
  26         movi    a4, ftrace_trace_function
  27         l32i    a4, a4, 0
  28         movi    a3, ftrace_stub
  29         bne     a3, a4, 1f
  30         retw
  31
  32 1:      xor     a7, a2, a1
  33         movi    a3, 0x3fffffff
  34         and     a7, a7, a3
  35         xor     a7, a7, a1
  36
  37         xor     a6, a0, a1
  38         and     a6, a6, a3
  39         xor     a6, a6, a1
  40         addi    a6, a6, -MCOUNT_INSN_SIZE
  41         callx4  a4
  42
  43         retw
  44
  45 ENDPROC(_mcount)
  46
  47 ENTRY(ftrace_stub)
  48         entry   a1, 16
  49         retw
  50 ENDPROC(ftrace_stub)