LXR linux/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
  18void ftrace_caller(void);
  19
  20extern char ftrace_graph_caller_end;
  21extern unsigned long ftrace_plt;
  22
  23struct 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
  31struct module;
  32struct dyn_ftrace;
  33/*
  34 * Either -mhotpatch or -mnop-mcount is used - no explicit init is required
  35 */
  36static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) { return 0; }
  37#define ftrace_init_nop ftrace_init_nop
  38
  39static inline unsigned long ftrace_call_adjust(unsigned long addr)
  40{
  41        return addr;
  42}
  43
  44struct ftrace_insn {
  45        u16 opc;
  46        s32 disp;
  47} __packed;
  48
  49static 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
  58static 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
  67static 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
  88static 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
  94static 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 */
 107