linux/arch/s390/include/asm/ftrace.h
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   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;
  22extern void *ftrace_func;
  23
  24struct dyn_arch_ftrace { };
  25
  26#define MCOUNT_ADDR 0
  27#define FTRACE_ADDR ((unsigned long)ftrace_caller)
  28
  29#define KPROBE_ON_FTRACE_NOP    0
  30#define KPROBE_ON_FTRACE_CALL   1
  31
  32struct module;
  33struct dyn_ftrace;
  34/*
  35 * Either -mhotpatch or -mnop-mcount is used - no explicit init is required
  36 */
  37static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) { return 0; }
  38#define ftrace_init_nop ftrace_init_nop
  39
  40static inline unsigned long ftrace_call_adjust(unsigned long addr)
  41{
  42        return addr;
  43}
  44
  45struct ftrace_insn {
  46        u16 opc;
  47        s32 disp;
  48} __packed;
  49
  50static inline void ftrace_generate_nop_insn(struct ftrace_insn *insn)
  51{
  52#ifdef CONFIG_FUNCTION_TRACER
  53        /* brcl 0,0 */
  54        insn->opc = 0xc004;
  55        insn->disp = 0;
  56#endif
  57}
  58
  59static inline int is_ftrace_nop(struct ftrace_insn *insn)
  60{
  61#ifdef CONFIG_FUNCTION_TRACER
  62        if (insn->disp == 0)
  63                return 1;
  64#endif
  65        return 0;
  66}
  67
  68static inline void ftrace_generate_call_insn(struct ftrace_insn *insn,
  69                                             unsigned long ip)
  70{
  71#ifdef CONFIG_FUNCTION_TRACER
  72        unsigned long target;
  73
  74        /* brasl r0,ftrace_caller */
  75        target = is_module_addr((void *) ip) ? ftrace_plt : FTRACE_ADDR;
  76        insn->opc = 0xc005;
  77        insn->disp = (target - ip) / 2;
  78#endif
  79}
  80
  81/*
  82 * Even though the system call numbers are identical for s390/s390x a
  83 * different system call table is used for compat tasks. This may lead
  84 * to e.g. incorrect or missing trace event sysfs files.
  85 * Therefore simply do not trace compat system calls at all.
  86 * See kernel/trace/trace_syscalls.c.
  87 */
  88#define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
  89static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
  90{
  91        return is_compat_task();
  92}
  93
  94#define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
  95static inline bool arch_syscall_match_sym_name(const char *sym,
  96                                               const char *name)
  97{
  98        /*
  99         * Skip __s390_ and __s390x_ prefix - due to compat wrappers
 100         * and aliasing some symbols of 64 bit system call functions
 101         * may get the __s390_ prefix instead of the __s390x_ prefix.
 102         */
 103        return !strcmp(sym + 7, name) || !strcmp(sym + 8, name);
 104}
 105
 106#endif /* __ASSEMBLY__ */
 107#endif /* _ASM_S390_FTRACE_H */
 108
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