Merge branch 'rt/arm' into rt/base

arch/arm/include/asm/ftrace.h

@@ -11,4 +11,38 @@ extern void mcount(void);
 
 #endif
 
+#ifndef __ASSEMBLY__
+
+#if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND)
+/*
+ * return_address uses walk_stackframe to do it's work.  If both
+ * CONFIG_FRAME_POINTER=y and CONFIG_ARM_UNWIND=y walk_stackframe uses unwind
+ * information.  For this to work in the function tracer many functions would
+ * have to be marked with __notrace.  So for now just depend on
+ * !CONFIG_ARM_UNWIND.
+ */
+
+void *return_address(unsigned int);
+
+#else
+
+extern inline void *return_address(unsigned int level)
+{
+	return NULL;
+}
+
+#endif
+
+#define HAVE_ARCH_CALLER_ADDR
+
+#define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
+#define CALLER_ADDR1 ((unsigned long)return_address(1))
+#define CALLER_ADDR2 ((unsigned long)return_address(2))
+#define CALLER_ADDR3 ((unsigned long)return_address(3))
+#define CALLER_ADDR4 ((unsigned long)return_address(4))
+#define CALLER_ADDR5 ((unsigned long)return_address(5))
+#define CALLER_ADDR6 ((unsigned long)return_address(6))
+
+#endif /* ifndef __ASSEMBLY__ */
+
 #endif /* _ASM_ARM_FTRACE */

arch/arm/kernel/Makefile

@@ -8,10 +8,12 @@ ifdef CONFIG_DYNAMIC_FTRACE
 CFLAGS_REMOVE_ftrace.o = -pg
 endif
 
+CFLAGS_REMOVE_return_address.o = -pg
+
 # Object file lists.
 
 obj-y		:= compat.o elf.o entry-armv.o entry-common.o irq.o \
-		   process.o ptrace.o setup.o signal.o \
+		   process.o ptrace.o return_address.o setup.o signal.o \
 		   sys_arm.o stacktrace.o time.o traps.o
 
 obj-$(CONFIG_ISA_DMA_API)	+= dma.o

arch/arm/kernel/entry-common.S

@@ -148,7 +148,7 @@ trace:
 	sub r0, r0, #MCOUNT_INSN_SIZE
 	mov lr, pc
 	mov pc, r2
-	mov lr, r1				@ restore lr
+	ldr lr, [fp, #-4]			@ restore lr
 	ldmia sp!, {r0-r3, pc}
 
 #endif /* CONFIG_DYNAMIC_FTRACE */

arch/arm/kernel/return_address.c

+/*
+ * arch/arm/kernel/return_address.c
+ *
+ * Copyright (C) 2009 Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
+ * for Pengutronix
+ *
+ * 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/module.h>
+
+#if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND)
+#include <linux/sched.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->lr;
+
+		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 + 1;
+
+	frame.fp = (unsigned long)__builtin_frame_address(0);
+	frame.sp = current_sp;
+	frame.lr = (unsigned long)__builtin_return_address(0);
+	frame.pc = (unsigned long)return_address;
+
+	walk_stackframe(&frame, save_return_addr, &data);
+
+	if (!data.level)
+		return data.addr;
+	else
+		return NULL;
+}
+
+#else /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) */
+
+#if defined(CONFIG_ARM_UNWIND)
+#warning "TODO: return_address should use unwind tables"
+#endif
+
+void *return_address(unsigned int level)
+{
+	return NULL;
+}
+
+#endif /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) / else */
+
+EXPORT_SYMBOL_GPL(return_address);

arch/arm/kernel/stacktrace.c

@@ -21,7 +21,7 @@
  * Note that with framepointer enabled, even the leaf functions have the same
  * prologue and epilogue, therefore we can ignore the LR value in this case.
  */
-int unwind_frame(struct stackframe *frame)
+int notrace unwind_frame(struct stackframe *frame)
 {
 	unsigned long high, low;
 	unsigned long fp = frame->fp;
@@ -43,7 +43,7 @@ int unwind_frame(struct stackframe *frame)
 }
 #endif
 
-void walk_stackframe(struct stackframe *frame,
+void notrace walk_stackframe(struct stackframe *frame,
 		     int (*fn)(struct stackframe *, void *), void *data)
 {
 	while (1) {