1 files changed, 118 insertions, 0 deletions
diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h
new file mode 100644
index 000000000..c72c179a5
--- /dev/null
+++ b/arch/s390/include/asm/ftrace.h
@@ -0,0 +1,118 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_S390_FTRACE_H
+#define _ASM_S390_FTRACE_H
+
+#define ARCH_SUPPORTS_FTRACE_OPS 1
+
+#if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)
+#define MCOUNT_INSN_SIZE	6
+#else
+#define MCOUNT_INSN_SIZE	24
+#define MCOUNT_RETURN_FIXUP	18
+#endif
+
+#define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
+
+#ifndef __ASSEMBLY__
+
+#ifdef CONFIG_CC_IS_CLANG
+/* https://bugs.llvm.org/show_bug.cgi?id=41424 */
+#define ftrace_return_address(n) 0UL
+#else
+#define ftrace_return_address(n) __builtin_return_address(n)
+#endif
+
+void _mcount(void);
+void ftrace_caller(void);
+
+extern char ftrace_graph_caller_end;
+extern unsigned long ftrace_plt;
+extern void *ftrace_func;
+
+struct dyn_arch_ftrace { };
+
+#define MCOUNT_ADDR ((unsigned long)_mcount)
+#define FTRACE_ADDR ((unsigned long)ftrace_caller)
+
+#define KPROBE_ON_FTRACE_NOP	0
+#define KPROBE_ON_FTRACE_CALL	1
+
+static inline unsigned long ftrace_call_adjust(unsigned long addr)
+{
+	return addr;
+}
+
+struct ftrace_insn {
+	u16 opc;
+	s32 disp;
+} __packed;
+
+static inline void ftrace_generate_nop_insn(struct ftrace_insn *insn)
+{
+#ifdef CONFIG_FUNCTION_TRACER
+#if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)
+	/* brcl 0,0 */
+	insn->opc = 0xc004;
+	insn->disp = 0;
+#else
+	/* jg .+24 */
+	insn->opc = 0xc0f4;
+	insn->disp = MCOUNT_INSN_SIZE / 2;
+#endif
+#endif
+}
+
+static inline int is_ftrace_nop(struct ftrace_insn *insn)
+{
+#ifdef CONFIG_FUNCTION_TRACER
+#if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)
+	if (insn->disp == 0)
+		return 1;
+#else
+	if (insn->disp == MCOUNT_INSN_SIZE / 2)
+		return 1;
+#endif
+#endif
+	return 0;
+}
+
+static inline void ftrace_generate_call_insn(struct ftrace_insn *insn,
+					     unsigned long ip)
+{
+#ifdef CONFIG_FUNCTION_TRACER
+	unsigned long target;
+
+	/* brasl r0,ftrace_caller */
+	target = is_module_addr((void *) ip) ? ftrace_plt : FTRACE_ADDR;
+	insn->opc = 0xc005;
+	insn->disp = (target - ip) / 2;
+#endif
+}
+
+/*
+ * Even though the system call numbers are identical for s390/s390x a
+ * different system call table is used for compat tasks. This may lead
+ * to e.g. incorrect or missing trace event sysfs files.
+ * Therefore simply do not trace compat system calls at all.
+ * See kernel/trace/trace_syscalls.c.
+ */
+#define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
+static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
+{
+	return is_compat_task();
+}
+
+#define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
+static inline bool arch_syscall_match_sym_name(const char *sym,
+					       const char *name)
+{
+	/*
+	 * Skip __s390_ and __s390x_ prefix - due to compat wrappers
+	 * and aliasing some symbols of 64 bit system call functions
+	 * may get the __s390_ prefix instead of the __s390x_ prefix.
+	 */
+	return !strcmp(sym + 7, name) || !strcmp(sym + 8, name);
+}
+
+#endif /* __ASSEMBLY__ */
+#endif /* _ASM_S390_FTRACE_H */