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
  11         .section .kprobes.text, "ax"
  12
  13 ENTRY(ftrace_stub)
  14         br      %r14
  15
  16 ENTRY(_mcount)
  17 #ifdef CONFIG_DYNAMIC_FTRACE
  18         br      %r14
  19
  20 ENTRY(ftrace_caller)
  21 #endif
  22         larl    %r1,function_trace_stop
  23         icm     %r1,0xf,0(%r1)
  24         bnzr    %r14
  25         stmg    %r2,%r5,32(%r15)
  26         stg     %r14,112(%r15)
  27         lgr     %r1,%r15
  28         aghi    %r15,-160
  29         stg     %r1,__SF_BACKCHAIN(%r15)
  30         lgr     %r2,%r14
  31         lg      %r3,168(%r15)
  32         larl    %r14,ftrace_trace_function
  33         lg      %r14,0(%r14)
  34         basr    %r14,%r14
  35 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  36         lg      %r2,168(%r15)
  37         lg      %r3,272(%r15)
  38 ENTRY(ftrace_graph_caller)
  39 # The bras instruction gets runtime patched to call prepare_ftrace_return.
  40 # See ftrace_enable_ftrace_graph_caller. The patched instruction is:
  41 #       bras    %r14,prepare_ftrace_return
  42         bras    %r14,0f
  43 0:      stg     %r2,168(%r15)
  44 #endif
  45         aghi    %r15,160
  46         lmg     %r2,%r5,32(%r15)
  47         lg      %r14,112(%r15)
  48         br      %r14
  49
  50 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  51
  52 ENTRY(return_to_handler)
  53         stmg    %r2,%r5,32(%r15)
  54         lgr     %r1,%r15
  55         aghi    %r15,-160
  56         stg     %r1,__SF_BACKCHAIN(%r15)
  57         brasl   %r14,ftrace_return_to_handler
  58         aghi    %r15,160
  59         lgr     %r14,%r2
  60         lmg     %r2,%r5,32(%r15)
  61         br      %r14
  62
  63 #endif