arm64: ftrace: Add CALLER_ADDRx macros
CALLER_ADDRx returns caller's address at specified level in call stacks.
They are used for several tracers like irqsoff and preemptoff.
Strange to say, however, they are refered even without FTRACE.
Signed-off-by: AKASHI Takahiro <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index ed5c448..41e8670 100644
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -18,6 +18,7 @@
#ifndef __ASSEMBLY__
extern void _mcount(unsigned long);
+extern void *return_address(unsigned int);
struct dyn_arch_ftrace {
/* No extra data needed for arm64 */
@@ -33,6 +34,8 @@
*/
return addr;
}
-#endif /* __ASSEMBLY__ */
+
+#define ftrace_return_address(n) return_address(n)
+#endif /* ifndef __ASSEMBLY__ */
#endif /* __ASM_FTRACE_H */
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 1ebcb4c..1f4d891 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -7,12 +7,13 @@
CFLAGS_REMOVE_ftrace.o = -pg
CFLAGS_REMOVE_insn.o = -pg
+CFLAGS_REMOVE_return_address.o = -pg
# Object file lists.
arm64-obj-y := cputable.o debug-monitors.o entry.o irq.o fpsimd.o \
entry-fpsimd.o process.o ptrace.o setup.o signal.o \
sys.o stacktrace.o time.o traps.o io.o vdso.o \
- hyp-stub.o psci.o cpu_ops.o insn.o
+ hyp-stub.o psci.o cpu_ops.o insn.o return_address.o
arm64-obj-$(CONFIG_COMPAT) += sys32.o kuser32.o signal32.o \
sys_compat.o
diff --git a/arch/arm64/kernel/return_address.c b/arch/arm64/kernel/return_address.c
new file mode 100644
index 0000000..89102a6
--- /dev/null
+++ b/arch/arm64/kernel/return_address.c
@@ -0,0 +1,55 @@
+/*
+ * arch/arm64/kernel/return_address.c
+ *
+ * Copyright (C) 2013 Linaro Limited
+ * Author: AKASHI Takahiro <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/export.h>
+#include <linux/ftrace.h>
+
+#include <asm/stacktrace.h>
+
+struct return_address_data {
+ unsigned int level;
+ void *addr;
+};
+
+static int save_return_addr(struct stackframe *frame, void *d)
+{
+ struct return_address_data *data = d;
+
+ if (!data->level) {
+ data->addr = (void *)frame->pc;
+ return 1;
+ } else {
+ --data->level;
+ return 0;
+ }
+}
+
+void *return_address(unsigned int level)
+{
+ struct return_address_data data;
+ struct stackframe frame;
+ register unsigned long current_sp asm ("sp");
+
+ data.level = level + 2;
+ data.addr = NULL;
+
+ frame.fp = (unsigned long)__builtin_frame_address(0);
+ frame.sp = current_sp;
+ frame.pc = (unsigned long)return_address; /* dummy */
+
+ walk_stackframe(&frame, save_return_addr, &data);
+
+ if (!data.level)
+ return data.addr;
+ else
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(return_address);
