arch/s390/include/asm/ftrace.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_S390_FTRACE_H
   3 #define _ASM_S390_FTRACE_H
   4
   5 #define ARCH_SUPPORTS_FTRACE_OPS 1
   6
   7 #ifdef CC_USING_HOTPATCH
   8 #define MCOUNT_INSN_SIZE        6
   9 #else
  10 #define MCOUNT_INSN_SIZE        24
  11 #define MCOUNT_RETURN_FIXUP     18
  12 #endif
  13
  14 #ifndef __ASSEMBLY__
  15
  16 #define ftrace_return_address(n) __builtin_return_address(n)
  17
  18 void _mcount(void);
  19 void ftrace_caller(void);
  20
  21 extern char ftrace_graph_caller_end;
  22 extern unsigned long ftrace_plt;
  23
  24 struct dyn_arch_ftrace { };
  25
  26 #define MCOUNT_ADDR ((unsigned long)_mcount)
  27 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
  28
  29 #define KPROBE_ON_FTRACE_NOP    0
  30 #define KPROBE_ON_FTRACE_CALL   1
  31
  32 static inline unsigned long ftrace_call_adjust(unsigned long addr)
  33 {
  34         return addr;
  35 }
  36
  37 struct ftrace_insn {
  38         u16 opc;
  39         s32 disp;
  40 } __packed;
  41
  42 static inline void ftrace_generate_nop_insn(struct ftrace_insn *insn)
  43 {
  44 #ifdef CONFIG_FUNCTION_TRACER
  45 #ifdef CC_USING_HOTPATCH
  46         /* brcl 0,0 */
  47         insn->opc = 0xc004;
  48         insn->disp = 0;
  49 #else
  50         /* jg .+24 */
  51         insn->opc = 0xc0f4;
  52         insn->disp = MCOUNT_INSN_SIZE / 2;
  53 #endif
  54 #endif
  55 }
  56
  57 static inline int is_ftrace_nop(struct ftrace_insn *insn)
  58 {
  59 #ifdef CONFIG_FUNCTION_TRACER
  60 #ifdef CC_USING_HOTPATCH
  61         if (insn->disp == 0)
  62                 return 1;
  63 #else
  64         if (insn->disp == MCOUNT_INSN_SIZE / 2)
  65                 return 1;
  66 #endif
  67 #endif
  68         return 0;
  69 }
  70
  71 static inline void ftrace_generate_call_insn(struct ftrace_insn *insn,
  72                                              unsigned long ip)
  73 {
  74 #ifdef CONFIG_FUNCTION_TRACER
  75         unsigned long target;
  76
  77         /* brasl r0,ftrace_caller */
  78         target = is_module_addr((void *) ip) ? ftrace_plt : FTRACE_ADDR;
  79         insn->opc = 0xc005;
  80         insn->disp = (target - ip) / 2;
  81 #endif
  82 }
  83
  84 #endif /* __ASSEMBLY__ */
  85 #endif /* _ASM_S390_FTRACE_H */