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 HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
   6 #define ARCH_SUPPORTS_FTRACE_OPS 1
   7 #define MCOUNT_INSN_SIZE        6
   8
   9 #ifndef __ASSEMBLY__
  10
  11 #ifdef CONFIG_CC_IS_CLANG
  12 /* https://bugs.llvm.org/show_bug.cgi?id=41424 */
  13 #define ftrace_return_address(n) 0UL
  14 #else
  15 #define ftrace_return_address(n) __builtin_return_address(n)
  16 #endif
  17
  18 void ftrace_caller(void);
  19
  20 extern char ftrace_graph_caller_end;
  21 extern unsigned long ftrace_plt;
  22
  23 struct dyn_arch_ftrace { };
  24
  25 #define MCOUNT_ADDR 0
  26 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
  27
  28 #define KPROBE_ON_FTRACE_NOP    0
  29 #define KPROBE_ON_FTRACE_CALL   1
  30
  31 struct module;
  32 struct dyn_ftrace;
  33 /*
  34  * Either -mhotpatch or -mnop-mcount is used - no explicit init is required
  35  */
  36 static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) { return 0; }
  37 #define ftrace_init_nop ftrace_init_nop
  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         /* brcl 0,0 */
  53         insn->opc = 0xc004;
  54         insn->disp = 0;
  55 #endif
  56 }
  57
  58 static inline int is_ftrace_nop(struct ftrace_insn *insn)
  59 {
  60 #ifdef CONFIG_FUNCTION_TRACER
  61         if (insn->disp == 0)
  62                 return 1;
  63 #endif
  64         return 0;
  65 }
  66
  67 static inline void ftrace_generate_call_insn(struct ftrace_insn *insn,
  68                                              unsigned long ip)
  69 {
  70 #ifdef CONFIG_FUNCTION_TRACER
  71         unsigned long target;
  72
  73         /* brasl r0,ftrace_caller */
  74         target = is_module_addr((void *) ip) ? ftrace_plt : FTRACE_ADDR;
  75         insn->opc = 0xc005;
  76         insn->disp = (target - ip) / 2;
  77 #endif
  78 }
  79
  80 /*
  81  * Even though the system call numbers are identical for s390/s390x a
  82  * different system call table is used for compat tasks. This may lead
  83  * to e.g. incorrect or missing trace event sysfs files.
  84  * Therefore simply do not trace compat system calls at all.
  85  * See kernel/trace/trace_syscalls.c.
  86  */
  87 #define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
  88 static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
  89 {
  90         return is_compat_task();
  91 }
  92
  93 #define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
  94 static inline bool arch_syscall_match_sym_name(const char *sym,
  95                                                const char *name)
  96 {
  97         /*
  98          * Skip __s390_ and __s390x_ prefix - due to compat wrappers
  99          * and aliasing some symbols of 64 bit system call functions
 100          * may get the __s390_ prefix instead of the __s390x_ prefix.
 101          */
 102         return !strcmp(sym + 7, name) || !strcmp(sym + 8, name);
 103 }
 104
 105 #endif /* __ASSEMBLY__ */
 106 #endif /* _ASM_S390_FTRACE_H */