arch/s390/kernel/mcount64.S

   1 /*
   2  * Copyright IBM Corp. 2008, 2009
   3  *
   4  *   Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>,
   5  *
   6  */
   7
   8 #include <linux/linkage.h>
   9 #include <asm/asm-offsets.h>
  10 #include <asm/ftrace.h>
  11
  12         .section .kprobes.text, "ax"
  13
  14 ENTRY(ftrace_stub)
  15         br      %r14
  16
  17 ENTRY(_mcount)
  18 #ifdef CONFIG_DYNAMIC_FTRACE
  19         br      %r14
  20
  21 ENTRY(ftrace_caller)
  22 #endif
  23         stmg    %r2,%r5,32(%r15)
  24         stg     %r14,112(%r15)
  25         lgr     %r1,%r15
  26         aghi    %r15,-160
  27         stg     %r1,__SF_BACKCHAIN(%r15)
  28         lgr     %r2,%r14
  29         lg      %r3,168(%r15)
  30         aghi    %r2,-MCOUNT_INSN_SIZE
  31         larl    %r14,ftrace_trace_function
  32         lg      %r14,0(%r14)
  33         basr    %r14,%r14
  34 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  35         lg      %r2,168(%r15)
  36         lg      %r3,272(%r15)
  37 ENTRY(ftrace_graph_caller)
  38 # The bras instruction gets runtime patched to call prepare_ftrace_return.
  39 # See ftrace_enable_ftrace_graph_caller. The patched instruction is:
  40 #       bras    %r14,prepare_ftrace_return
  41         bras    %r14,0f
  42 0:      stg     %r2,168(%r15)
  43 #endif
  44         aghi    %r15,160
  45         lmg     %r2,%r5,32(%r15)
  46         lg      %r14,112(%r15)
  47         br      %r14
  48
  49 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  50
  51 ENTRY(return_to_handler)
  52         stmg    %r2,%r5,32(%r15)
  53         lgr     %r1,%r15
  54         aghi    %r15,-160
  55         stg     %r1,__SF_BACKCHAIN(%r15)
  56         brasl   %r14,ftrace_return_to_handler
  57         aghi    %r15,160
  58         lgr     %r14,%r2
  59         lmg     %r2,%r5,32(%r15)
  60         br      %r14
  61
  62 #endif