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 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
  25void _mcount(void);
  26void ftrace_caller(void);
  27
  28extern char ftrace_graph_caller_end;
  29extern unsigned long ftrace_plt;
  30
  31struct 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
  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#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
  64static 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
  78static 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
  99static 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
 105static 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 */
 118