3 files changed, 94 insertions, 11 deletions

diff --git a/arch/avr32/oprofile/Makefile b/arch/avr32/oprofile/Makefile
index 1fe81c3c1e8..e0eb520e028 100644
--- a/arch/avr32/oprofile/Makefile
+++ b/arch/avr32/oprofile/Makefile
@@ -5,4 +5,4 @@ oprofile-y		:= $(addprefix ../../../drivers/oprofile/,	\
 				event_buffer.o oprofile_files.o		\
 				oprofilefs.o oprofile_stats.o		\
 				timer_int.o)
-oprofile-y		+= op_model_avr32.o
+oprofile-y		+= op_model_avr32.o backtrace.o
diff --git a/arch/avr32/oprofile/backtrace.c b/arch/avr32/oprofile/backtrace.c
new file mode 100644
index 00000000000..75d9ad6f99c
--- /dev/null
+++ b/arch/avr32/oprofile/backtrace.c
@@ -0,0 +1,81 @@
+/*
+ * AVR32 specific backtracing code for oprofile
+ *
+ * Copyright 2008 Weinmann GmbH
+ *
+ * Author: Nikolaus Voss <n.voss@weinmann.de>
+ *
+ * Based on i386 oprofile backtrace code by John Levon and David Smith
+ *
+ * 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/oprofile.h>
+#include <linux/sched.h>
+#include <linux/uaccess.h>
+
+/* The first two words of each frame on the stack look like this if we have
+ * frame pointers */
+struct frame_head {
+	unsigned long lr;
+	struct frame_head *fp;
+};
+
+/* copied from arch/avr32/kernel/process.c */
+static inline int valid_stack_ptr(struct thread_info *tinfo, unsigned long p)
+{
+	return (p > (unsigned long)tinfo)
+		&& (p < (unsigned long)tinfo + THREAD_SIZE - 3);
+}
+
+/* copied from arch/x86/oprofile/backtrace.c */
+static struct frame_head *dump_user_backtrace(struct frame_head *head)
+{
+	struct frame_head bufhead[2];
+
+	/* Also check accessibility of one struct frame_head beyond */
+	if (!access_ok(VERIFY_READ, head, sizeof(bufhead)))
+		return NULL;
+	if (__copy_from_user_inatomic(bufhead, head, sizeof(bufhead)))
+		return NULL;
+
+	oprofile_add_trace(bufhead[0].lr);
+
+	/* frame pointers should strictly progress back up the stack
+	 * (towards higher addresses) */
+	if (bufhead[0].fp <= head)
+		return NULL;
+
+	return bufhead[0].fp;
+}
+
+void avr32_backtrace(struct pt_regs * const regs, unsigned int depth)
+{
+	/* Get first frame pointer */
+	struct frame_head *head = (struct frame_head *)(regs->r7);
+
+	if (!user_mode(regs)) {
+#ifdef CONFIG_FRAME_POINTER
+		/*
+		 * Traverse the kernel stack from frame to frame up to
+		 * "depth" steps.
+		 */
+		while (depth-- && valid_stack_ptr(task_thread_info(current),
+						  (unsigned long)head)) {
+			oprofile_add_trace(head->lr);
+			if (head->fp <= head)
+				break;
+			head = head->fp;
+		}
+#endif
+	} else {
+		/* Assume we have frame pointers in user mode process */
+		while (depth-- && head)
+			head = dump_user_backtrace(head);
+	}
+}
+
+
diff --git a/arch/avr32/oprofile/op_model_avr32.c b/arch/avr32/oprofile/op_model_avr32.c
index df42325c7f8..08308be2c02 100644
--- a/arch/avr32/oprofile/op_model_avr32.c
+++ b/arch/avr32/oprofile/op_model_avr32.c
@@ -17,11 +17,12 @@
 #include <linux/types.h>
 
 #include <asm/sysreg.h>
-#include <asm/system.h>
 
 #define AVR32_PERFCTR_IRQ_GROUP	0
 #define AVR32_PERFCTR_IRQ_LINE	1
 
+void avr32_backtrace(struct pt_regs * const regs, unsigned int depth);
+
 enum { PCCNT, PCNT0, PCNT1, NR_counter };
 
 struct avr32_perf_counter {
@@ -96,8 +97,7 @@ static irqreturn_t avr32_perf_counter_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static int avr32_perf_counter_create_files(struct super_block *sb,
-		struct dentry *root)
+static int avr32_perf_counter_create_files(struct dentry *root)
 {
 	struct dentry *dir;
 	unsigned int i;
@@ -105,21 +105,21 @@ static int avr32_perf_counter_create_files(struct super_block *sb,
 
 	for (i = 0; i < NR_counter; i++) {
 		snprintf(filename, sizeof(filename), "%u", i);
-		dir = oprofilefs_mkdir(sb, root, filename);
+		dir = oprofilefs_mkdir(root, filename);
 
-		oprofilefs_create_ulong(sb, dir, "enabled",
+		oprofilefs_create_ulong(dir, "enabled",
 				&counter[i].enabled);
-		oprofilefs_create_ulong(sb, dir, "event",
+		oprofilefs_create_ulong(dir, "event",
 				&counter[i].event);
-		oprofilefs_create_ulong(sb, dir, "count",
+		oprofilefs_create_ulong(dir, "count",
 				&counter[i].count);
 
 		/* Dummy entries */
-		oprofilefs_create_ulong(sb, dir, "kernel",
+		oprofilefs_create_ulong(dir, "kernel",
 				&counter[i].kernel);
-		oprofilefs_create_ulong(sb, dir, "user",
+		oprofilefs_create_ulong(dir, "user",
 				&counter[i].user);
-		oprofilefs_create_ulong(sb, dir, "unit_mask",
+		oprofilefs_create_ulong(dir, "unit_mask",
 				&counter[i].unit_mask);
 	}
 
@@ -223,6 +223,8 @@ int __init oprofile_arch_init(struct oprofile_operations *ops)
 	memcpy(ops, &avr32_perf_counter_ops,
 			sizeof(struct oprofile_operations));
 
+	ops->backtrace = avr32_backtrace;
+
 	printk(KERN_INFO "oprofile: using AVR32 performance monitoring.\n");
 
 	return 0;