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 #include <asm/ptrace.h>
  12
  13         .section .kprobes.text, "ax"
  14
  15 ENTRY(ftrace_stub)
  16         br      %r14
  17
  18 #define STACK_FRAME_SIZE  (STACK_FRAME_OVERHEAD + __PT_SIZE)
  19 #define STACK_PTREGS      (STACK_FRAME_OVERHEAD)
  20 #define STACK_PTREGS_GPRS (STACK_PTREGS + __PT_GPRS)
  21 #define STACK_PTREGS_PSW  (STACK_PTREGS + __PT_PSW)
  22
  23 ENTRY(_mcount)
  24         br      %r14
  25
  26 ENTRY(ftrace_caller)
  27         .globl  ftrace_regs_caller
  28         .set    ftrace_regs_caller,ftrace_caller
  29         lgr     %r1,%r15
  30         aghi    %r15,-STACK_FRAME_SIZE
  31         stg     %r1,__SF_BACKCHAIN(%r15)
  32         stg     %r1,(STACK_PTREGS_GPRS+15*8)(%r15)
  33         stg     %r0,(STACK_PTREGS_PSW+8)(%r15)
  34         stmg    %r2,%r14,(STACK_PTREGS_GPRS+2*8)(%r15)
  35 #ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
  36         aghik   %r2,%r0,-MCOUNT_INSN_SIZE
  37         lgrl    %r4,function_trace_op
  38         lgrl    %r1,ftrace_trace_function
  39 #else
  40         lgr     %r2,%r0
  41         aghi    %r2,-MCOUNT_INSN_SIZE
  42         larl    %r4,function_trace_op
  43         lg      %r4,0(%r4)
  44         larl    %r1,ftrace_trace_function
  45         lg      %r1,0(%r1)
  46 #endif
  47         lgr     %r3,%r14
  48         la      %r5,STACK_PTREGS(%r15)
  49         basr    %r14,%r1
  50 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  51 # The j instruction gets runtime patched to a nop instruction.
  52 # See ftrace_enable_ftrace_graph_caller. The patched instruction is:
  53 #       j       .+4
  54 ENTRY(ftrace_graph_caller)
  55         j       ftrace_graph_caller_end
  56         lg      %r2,(STACK_PTREGS_GPRS+14*8)(%r15)
  57         lg      %r3,(STACK_PTREGS_PSW+8)(%r15)
  58         brasl   %r14,prepare_ftrace_return
  59         stg     %r2,(STACK_PTREGS_GPRS+14*8)(%r15)
  60 ftrace_graph_caller_end:
  61         .globl  ftrace_graph_caller_end
  62 #endif
  63         lg      %r1,(STACK_PTREGS_PSW+8)(%r15)
  64         lmg     %r2,%r15,(STACK_PTREGS_GPRS+2*8)(%r15)
  65         br      %r1
  66
  67 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  68
  69 ENTRY(return_to_handler)
  70         stmg    %r2,%r5,32(%r15)
  71         lgr     %r1,%r15
  72         aghi    %r15,-STACK_FRAME_OVERHEAD
  73         stg     %r1,__SF_BACKCHAIN(%r15)
  74         brasl   %r14,ftrace_return_to_handler
  75         aghi    %r15,STACK_FRAME_OVERHEAD
  76         lgr     %r14,%r2
  77         lmg     %r2,%r5,32(%r15)
  78         br      %r14
  79
  80 #endif