From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 arch/metag/oprofile/backtrace.c | 63 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 arch/metag/oprofile/backtrace.c

(limited to 'arch/metag/oprofile/backtrace.c')

diff --git a/arch/metag/oprofile/backtrace.c b/arch/metag/oprofile/backtrace.c
new file mode 100644
index 000000000..7cc3f37cb
--- /dev/null
+++ b/arch/metag/oprofile/backtrace.c
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2010-2013 Imagination Technologies Ltd.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/oprofile.h>
+#include <linux/uaccess.h>
+#include <asm/processor.h>
+#include <asm/stacktrace.h>
+
+#include "backtrace.h"
+
+static void user_backtrace_fp(unsigned long __user *fp, unsigned int depth)
+{
+	while (depth-- && access_ok(VERIFY_READ, fp, 8)) {
+		unsigned long addr;
+		unsigned long __user *fpnew;
+		if (__copy_from_user_inatomic(&addr, fp + 1, sizeof(addr)))
+			break;
+		addr -= 4;
+
+		oprofile_add_trace(addr);
+
+		/* stack grows up, so frame pointers must decrease */
+		if (__copy_from_user_inatomic(&fpnew, fp + 0, sizeof(fpnew)))
+			break;
+		if (fpnew >= fp)
+			break;
+		fp = fpnew;
+	}
+}
+
+static int kernel_backtrace_frame(struct stackframe *frame, void *data)
+{
+	unsigned int *depth = data;
+
+	oprofile_add_trace(frame->pc);
+
+	/* decrement depth and stop if we reach 0 */
+	if ((*depth)-- == 0)
+		return 1;
+
+	/* otherwise onto the next frame */
+	return 0;
+}
+
+void metag_backtrace(struct pt_regs * const regs, unsigned int depth)
+{
+	if (user_mode(regs)) {
+		unsigned long *fp = (unsigned long *)regs->ctx.AX[1].U0;
+		user_backtrace_fp((unsigned long __user __force *)fp, depth);
+	} else {
+		struct stackframe frame;
+		frame.fp = regs->ctx.AX[1].U0;		/* A0FrP */
+		frame.sp = user_stack_pointer(regs);	/* A0StP */
+		frame.lr = 0;				/* from stack */
+		frame.pc = regs->ctx.CurrPC;		/* PC */
+		walk_stackframe(&frame, &kernel_backtrace_frame, &depth);
+	}
+}
-- 
cgit v1.2.3-54-g00ecf