1 files changed, 91 insertions, 0 deletions
diff --git a/arch/sh/oprofile/backtrace.c b/arch/sh/oprofile/backtrace.c
new file mode 100644
index 00000000..9c88dcd5
--- /dev/null
+++ b/arch/sh/oprofile/backtrace.c
@@ -0,0 +1,91 @@
+/*
+ * SH specific backtracing code for oprofile
+ *
+ * Copyright 2007 STMicroelectronics Ltd.
+ *
+ * Author: Dave Peverley <dpeverley@mpc-data.co.uk>
+ *
+ * Based on ARM oprofile backtrace code by Richard Purdie and in turn, i386
+ * oprofile backtrace code by John Levon, 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/kallsyms.h>
+#include <linux/mm.h>
+#include <asm/unwinder.h>
+#include <asm/ptrace.h>
+#include <asm/uaccess.h>
+#include <asm/sections.h>
+#include <asm/stacktrace.h>
+
+static int backtrace_stack(void *data, char *name)
+{
+	/* Yes, we want all stacks */
+	return 0;
+}
+
+static void backtrace_address(void *data, unsigned long addr, int reliable)
+{
+	unsigned int *depth = data;
+
+	if ((*depth)--)
+		oprofile_add_trace(addr);
+}
+
+static struct stacktrace_ops backtrace_ops = {
+	.stack = backtrace_stack,
+	.address = backtrace_address,
+};
+
+/* Limit to stop backtracing too far. */
+static int backtrace_limit = 20;
+
+static unsigned long *
+user_backtrace(unsigned long *stackaddr, struct pt_regs *regs)
+{
+	unsigned long buf_stack;
+
+	/* Also check accessibility of address */
+	if (!access_ok(VERIFY_READ, stackaddr, sizeof(unsigned long)))
+		return NULL;
+
+	if (__copy_from_user_inatomic(&buf_stack, stackaddr, sizeof(unsigned long)))
+		return NULL;
+
+	/* Quick paranoia check */
+	if (buf_stack & 3)
+		return NULL;
+
+	oprofile_add_trace(buf_stack);
+
+	stackaddr++;
+
+	return stackaddr;
+}
+
+void sh_backtrace(struct pt_regs * const regs, unsigned int depth)
+{
+	unsigned long *stackaddr;
+
+	/*
+	 * Paranoia - clip max depth as we could get lost in the weeds.
+	 */
+	if (depth > backtrace_limit)
+		depth = backtrace_limit;
+
+	stackaddr = (unsigned long *)kernel_stack_pointer(regs);
+	if (!user_mode(regs)) {
+		if (depth)
+			unwind_stack(NULL, regs, stackaddr,
+				     &backtrace_ops, &depth);
+		return;
+	}
+
+	while (depth-- && (stackaddr != NULL))
+		stackaddr = user_backtrace(stackaddr, regs);
+}