1 files changed, 114 insertions, 0 deletions
diff --git a/arch/s390/kernel/mcount.S b/arch/s390/kernel/mcount.S
new file mode 100644
index 000000000..be9e85e75
--- /dev/null
+++ b/arch/s390/kernel/mcount.S
@@ -0,0 +1,114 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright IBM Corp. 2008, 2009
+ *
+ *   Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>,
+ *
+ */
+
+#include <linux/linkage.h>
+#include <asm/asm-offsets.h>
+#include <asm/ftrace.h>
+#include <asm/nospec-insn.h>
+#include <asm/ptrace.h>
+#include <asm/export.h>
+
+	GEN_BR_THUNK %r1
+	GEN_BR_THUNK %r14
+
+	.section .kprobes.text, "ax"
+
+ENTRY(ftrace_stub)
+	BR_EX	%r14
+ENDPROC(ftrace_stub)
+
+#define STACK_FRAME_SIZE  (STACK_FRAME_OVERHEAD + __PT_SIZE)
+#define STACK_PTREGS	  (STACK_FRAME_OVERHEAD)
+#define STACK_PTREGS_GPRS (STACK_PTREGS + __PT_GPRS)
+#define STACK_PTREGS_PSW  (STACK_PTREGS + __PT_PSW)
+#ifdef __PACK_STACK
+/* allocate just enough for r14, r15 and backchain */
+#define TRACED_FUNC_FRAME_SIZE	24
+#else
+#define TRACED_FUNC_FRAME_SIZE	STACK_FRAME_OVERHEAD
+#endif
+
+ENTRY(_mcount)
+	BR_EX	%r14
+ENDPROC(_mcount)
+EXPORT_SYMBOL(_mcount)
+
+ENTRY(ftrace_caller)
+	.globl	ftrace_regs_caller
+	.set	ftrace_regs_caller,ftrace_caller
+	stg	%r14,(__SF_GPRS+8*8)(%r15)	# save traced function caller
+	lghi	%r14,0				# save condition code
+	ipm	%r14				# don't put any instructions
+	sllg	%r14,%r14,16			# clobbering CC before this point
+	lgr	%r1,%r15
+#if !(defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT))
+	aghi	%r0,MCOUNT_RETURN_FIXUP
+#endif
+	# allocate stack frame for ftrace_caller to contain traced function
+	aghi	%r15,-TRACED_FUNC_FRAME_SIZE
+	stg	%r1,__SF_BACKCHAIN(%r15)
+	stg	%r0,(__SF_GPRS+8*8)(%r15)
+	stg	%r15,(__SF_GPRS+9*8)(%r15)
+	# allocate pt_regs and stack frame for ftrace_trace_function
+	aghi	%r15,-STACK_FRAME_SIZE
+	stg	%r1,(STACK_PTREGS_GPRS+15*8)(%r15)
+	stg	%r14,(STACK_PTREGS_PSW)(%r15)
+	lg	%r14,(__SF_GPRS+8*8)(%r1)	# restore original return address
+	stosm	(STACK_PTREGS_PSW)(%r15),0
+	aghi	%r1,-TRACED_FUNC_FRAME_SIZE
+	stg	%r1,__SF_BACKCHAIN(%r15)
+	stg	%r0,(STACK_PTREGS_PSW+8)(%r15)
+	stmg	%r2,%r14,(STACK_PTREGS_GPRS+2*8)(%r15)
+#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
+	aghik	%r2,%r0,-MCOUNT_INSN_SIZE
+	lgrl	%r4,function_trace_op
+	lgrl	%r1,ftrace_func
+#else
+	lgr	%r2,%r0
+	aghi	%r2,-MCOUNT_INSN_SIZE
+	larl	%r4,function_trace_op
+	lg	%r4,0(%r4)
+	larl	%r1,ftrace_func
+	lg	%r1,0(%r1)
+#endif
+	lgr	%r3,%r14
+	la	%r5,STACK_PTREGS(%r15)
+	BASR_EX	%r14,%r1
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+# The j instruction gets runtime patched to a nop instruction.
+# See ftrace_enable_ftrace_graph_caller.
+	.globl ftrace_graph_caller
+ftrace_graph_caller:
+	j	ftrace_graph_caller_end
+	lmg	%r2,%r3,(STACK_PTREGS_GPRS+14*8)(%r15)
+	lg	%r4,(STACK_PTREGS_PSW+8)(%r15)
+	brasl	%r14,prepare_ftrace_return
+	stg	%r2,(STACK_PTREGS_GPRS+14*8)(%r15)
+ftrace_graph_caller_end:
+	.globl	ftrace_graph_caller_end
+#endif
+	lg	%r1,(STACK_PTREGS_PSW+8)(%r15)
+	lmg	%r2,%r15,(STACK_PTREGS_GPRS+2*8)(%r15)
+	BR_EX	%r1
+ENDPROC(ftrace_caller)
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+ENTRY(return_to_handler)
+	stmg	%r2,%r5,32(%r15)
+	lgr	%r1,%r15
+	aghi	%r15,-STACK_FRAME_OVERHEAD
+	stg	%r1,__SF_BACKCHAIN(%r15)
+	brasl	%r14,ftrace_return_to_handler
+	aghi	%r15,STACK_FRAME_OVERHEAD
+	lgr	%r14,%r2
+	lmg	%r2,%r5,32(%r15)
+	BR_EX	%r14
+ENDPROC(return_to_handler)
+
+#endif