arch/s390/kernel/mcount.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 #include <asm/ptrace.h>
  12 #include <asm/export.h>
  13
  14         .section .kprobes.text, "ax"
  15
  16 ENTRY(ftrace_stub)
  17         br      %r14
  18
  19 #define STACK_FRAME_SIZE  (STACK_FRAME_OVERHEAD + __PT_SIZE)
  20 #define STACK_PTREGS      (STACK_FRAME_OVERHEAD)
  21 #define STACK_PTREGS_GPRS (STACK_PTREGS + __PT_GPRS)
  22 #define STACK_PTREGS_PSW  (STACK_PTREGS + __PT_PSW)
  23
  24 ENTRY(_mcount)
  25         br      %r14
  26
  27 EXPORT_SYMBOL(_mcount)
  28
  29 ENTRY(ftrace_caller)
  30         .globl  ftrace_regs_caller
  31         .set    ftrace_regs_caller,ftrace_caller
  32         lgr     %r1,%r15
  33 #ifndef CC_USING_HOTPATCH
  34         aghi    %r0,MCOUNT_RETURN_FIXUP
  35 #endif
  36         aghi    %r15,-STACK_FRAME_SIZE
  37         stg     %r1,__SF_BACKCHAIN(%r15)
  38         stg     %r1,(STACK_PTREGS_GPRS+15*8)(%r15)
  39         stg     %r0,(STACK_PTREGS_PSW+8)(%r15)
  40         stmg    %r2,%r14,(STACK_PTREGS_GPRS+2*8)(%r15)
  41 #ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
  42         aghik   %r2,%r0,-MCOUNT_INSN_SIZE
  43         lgrl    %r4,function_trace_op
  44         lgrl    %r1,ftrace_trace_function
  45 #else
  46         lgr     %r2,%r0
  47         aghi    %r2,-MCOUNT_INSN_SIZE
  48         larl    %r4,function_trace_op
  49         lg      %r4,0(%r4)
  50         larl    %r1,ftrace_trace_function
  51         lg      %r1,0(%r1)
  52 #endif
  53         lgr     %r3,%r14
  54         la      %r5,STACK_PTREGS(%r15)
  55         basr    %r14,%r1
  56 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  57 # The j instruction gets runtime patched to a nop instruction.
  58 # See ftrace_enable_ftrace_graph_caller.
  59 ENTRY(ftrace_graph_caller)
  60         j       ftrace_graph_caller_end
  61         lg      %r2,(STACK_PTREGS_GPRS+14*8)(%r15)
  62         lg      %r3,(STACK_PTREGS_PSW+8)(%r15)
  63         brasl   %r14,prepare_ftrace_return
  64         stg     %r2,(STACK_PTREGS_GPRS+14*8)(%r15)
  65 ftrace_graph_caller_end:
  66         .globl  ftrace_graph_caller_end
  67 #endif
  68         lg      %r1,(STACK_PTREGS_PSW+8)(%r15)
  69         lmg     %r2,%r15,(STACK_PTREGS_GPRS+2*8)(%r15)
  70         br      %r1
  71
  72 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  73
  74 ENTRY(return_to_handler)
  75         stmg    %r2,%r5,32(%r15)
  76         lgr     %r1,%r15
  77         aghi    %r15,-STACK_FRAME_OVERHEAD
  78         stg     %r1,__SF_BACKCHAIN(%r15)
  79         brasl   %r14,ftrace_return_to_handler
  80         aghi    %r15,STACK_FRAME_OVERHEAD
  81         lgr     %r14,%r2
  82         lmg     %r2,%r5,32(%r15)
  83         br      %r14
  84
  85 #endif