Initial import of modified Linux 2.6.28 tree

Original upstream URL:
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git | branch linux-2.6.28.y

1 files changed, 90 insertions, 0 deletions

diff --git a/arch/x86/oprofile/backtrace.c b/arch/x86/oprofile/backtrace.c
new file mode 100644
index 0000000..04df67f
--- /dev/null
+++ b/arch/x86/oprofile/backtrace.c
@@ -0,0 +1,90 @@
+/**
+ * @file backtrace.c
+ *
+ * @remark Copyright 2002 OProfile authors
+ * @remark Read the file COPYING
+ *
+ * @author John Levon
+ * @author David Smith
+ */
+
+#include <linux/oprofile.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <asm/ptrace.h>
+#include <asm/uaccess.h>
+#include <asm/stacktrace.h>
+
+static void backtrace_warning_symbol(void *data, char *msg,
+				     unsigned long symbol)
+{
+	/* Ignore warnings */
+}
+
+static void backtrace_warning(void *data, char *msg)
+{
+	/* Ignore warnings */
+}
+
+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 = {
+	.warning = backtrace_warning,
+	.warning_symbol = backtrace_warning_symbol,
+	.stack = backtrace_stack,
+	.address = backtrace_address,
+};
+
+struct frame_head {
+	struct frame_head *bp;
+	unsigned long ret;
+} __attribute__((packed));
+
+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].ret);
+
+	/* frame pointers should strictly progress back up the stack
+	 * (towards higher addresses) */
+	if (head >= bufhead[0].bp)
+		return NULL;
+
+	return bufhead[0].bp;
+}
+
+void
+x86_backtrace(struct pt_regs * const regs, unsigned int depth)
+{
+	struct frame_head *head = (struct frame_head *)frame_pointer(regs);
+	unsigned long stack = kernel_trap_sp(regs);
+
+	if (!user_mode_vm(regs)) {
+		if (depth)
+			dump_trace(NULL, regs, (unsigned long *)stack, 0,
+				   &backtrace_ops, &depth);
+		return;
+	}
+
+	while (depth-- && head)
+		head = dump_user_backtrace(head);
+}