root/arch/s390/include/asm/ftrace.h

INCLUDED FROM

DEFINITIONS

1. ftrace_call_adjust
2. ftrace_generate_nop_insn
3. is_ftrace_nop
4. ftrace_generate_call_insn
5. arch_trace_is_compat_syscall
6. arch_syscall_match_sym_name

   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 #if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)
   8 #define MCOUNT_INSN_SIZE        6
   9 #else
  10 #define MCOUNT_INSN_SIZE        24
  11 #define MCOUNT_RETURN_FIXUP     18
  12 #endif
  13 
  14 #define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
  15 
  16 #ifndef __ASSEMBLY__
  17 
  18 #ifdef CONFIG_CC_IS_CLANG
  19 /* https://bugs.llvm.org/show_bug.cgi?id=41424 */
  20 #define ftrace_return_address(n) 0UL
  21 #else
  22 #define ftrace_return_address(n) __builtin_return_address(n)
  23 #endif
  24 
  25 void _mcount(void);
  26 void ftrace_caller(void);
  27 
  28 extern char ftrace_graph_caller_end;
  29 extern unsigned long ftrace_plt;
  30 
  31 struct dyn_arch_ftrace { };
  32 
  33 #define MCOUNT_ADDR ((unsigned long)_mcount)
  34 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
  35 
  36 #define KPROBE_ON_FTRACE_NOP    0
  37 #define KPROBE_ON_FTRACE_CALL   1
  38 
  39 static inline unsigned long ftrace_call_adjust(unsigned long addr)
  40 {
  41         return addr;
  42 }
  43 
  44 struct ftrace_insn {
  45         u16 opc;
  46         s32 disp;
  47 } __packed;
  48 
  49 static inline void ftrace_generate_nop_insn(struct ftrace_insn *insn)
  50 {
  51 #ifdef CONFIG_FUNCTION_TRACER
  52 #if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)
  53         /* brcl 0,0 */
  54         insn->opc = 0xc004;
  55         insn->disp = 0;
  56 #else
  57         /* jg .+24 */
  58         insn->opc = 0xc0f4;
  59         insn->disp = MCOUNT_INSN_SIZE / 2;
  60 #endif
  61 #endif
  62 }
  63 
  64 static inline int is_ftrace_nop(struct ftrace_insn *insn)
  65 {
  66 #ifdef CONFIG_FUNCTION_TRACER
  67 #if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)
  68         if (insn->disp == 0)
  69                 return 1;
  70 #else
  71         if (insn->disp == MCOUNT_INSN_SIZE / 2)
  72                 return 1;
  73 #endif
  74 #endif
  75         return 0;
  76 }
  77 
  78 static inline void ftrace_generate_call_insn(struct ftrace_insn *insn,
  79                                              unsigned long ip)
  80 {
  81 #ifdef CONFIG_FUNCTION_TRACER
  82         unsigned long target;
  83 
  84         /* brasl r0,ftrace_caller */
  85         target = is_module_addr((void *) ip) ? ftrace_plt : FTRACE_ADDR;
  86         insn->opc = 0xc005;
  87         insn->disp = (target - ip) / 2;
  88 #endif
  89 }
  90 
  91 /*
  92  * Even though the system call numbers are identical for s390/s390x a
  93  * different system call table is used for compat tasks. This may lead
  94  * to e.g. incorrect or missing trace event sysfs files.
  95  * Therefore simply do not trace compat system calls at all.
  96  * See kernel/trace/trace_syscalls.c.
  97  */
  98 #define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
  99 static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
 100 {
 101         return is_compat_task();
 102 }
 103 
 104 #define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
 105 static inline bool arch_syscall_match_sym_name(const char *sym,
 106                                                const char *name)
 107 {
 108         /*
 109          * Skip __s390_ and __s390x_ prefix - due to compat wrappers
 110          * and aliasing some symbols of 64 bit system call functions
 111          * may get the __s390_ prefix instead of the __s390x_ prefix.
 112          */
 113         return !strcmp(sym + 7, name) || !strcmp(sym + 8, name);
 114 }
 115 
 116 #endif /* __ASSEMBLY__ */
 117 #endif /* _ASM_S390_FTRACE_H */