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 <takahiro.akashi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index ed5c448ece991165ee322f8afc05610b3de88ba9..41e8670db20f6403a9d3616a56370da1f0ec326f 100644 (file)
--- 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 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
         */
        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 1ebcb4c6b5d8d1e377aed2332982f65fdd06bfe8..1f4d8913ceb388828681b010c0fa33e10b885dc6 100644 (file)
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -7,12 +7,13 @@ AFLAGS_head.o         := -DTEXT_OFFSET=$(TEXT_OFFSET)
 
 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 (file)
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 <takahiro.akashi@linaro.org>
+ *
+ * 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);