1 files changed, 140 insertions, 0 deletions
diff --git a/arch/blackfin/kernel/ftrace-entry.S b/arch/blackfin/kernel/ftrace-entry.S
new file mode 100644
index 0000000..6980b7a
--- /dev/null
+++ b/arch/blackfin/kernel/ftrace-entry.S
@@ -0,0 +1,140 @@
+/*
+ * mcount and friends -- ftrace stuff
+ *
+ * Copyright (C) 2009 Analog Devices Inc.
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/linkage.h>
+#include <asm/ftrace.h>
+
+.text
+
+/* GCC will have called us before setting up the function prologue, so we
+ * can clobber the normal scratch registers, but we need to make sure to
+ * save/restore the registers used for argument passing (R0-R2) in case
+ * the profiled function is using them.  With data registers, R3 is the
+ * only one we can blow away.  With pointer registers, we have P0-P2.
+ *
+ * Upon entry, the RETS will point to the top of the current profiled
+ * function.  And since GCC setup the frame for us, the previous function
+ * will be waiting there.  mmmm pie.
+ */
+ENTRY(__mcount)
+	/* save third function arg early so we can do testing below */
+	[--sp] = r2;
+
+	/* load the function pointer to the tracer */
+	p0.l = _ftrace_trace_function;
+	p0.h = _ftrace_trace_function;
+	r3 = [p0];
+
+	/* optional micro optimization: don't call the stub tracer */
+	r2.l = _ftrace_stub;
+	r2.h = _ftrace_stub;
+	cc = r2 == r3;
+	if ! cc jump .Ldo_trace;
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	/* if the ftrace_graph_return function pointer is not set to
+	 * the ftrace_stub entry, call prepare_ftrace_return().
+	 */
+	p0.l = _ftrace_graph_return;
+	p0.h = _ftrace_graph_return;
+	r3 = [p0];
+	cc = r2 == r3;
+	if ! cc jump _ftrace_graph_caller;
+
+	/* similarly, if the ftrace_graph_entry function pointer is not
+	 * set to the ftrace_graph_entry_stub entry, ...
+	 */
+	p0.l = _ftrace_graph_entry;
+	p0.h = _ftrace_graph_entry;
+	r2.l = _ftrace_graph_entry_stub;
+	r2.h = _ftrace_graph_entry_stub;
+	r3 = [p0];
+	cc = r2 == r3;
+	if ! cc jump _ftrace_graph_caller;
+#endif
+
+	r2 = [sp++];
+	rts;
+
+.Ldo_trace:
+
+	/* save first/second function arg and the return register */
+	[--sp] = r0;
+	[--sp] = r1;
+	[--sp] = rets;
+
+	/* setup the tracer function */
+	p0 = r3;
+
+	/* tracer(ulong frompc, ulong selfpc):
+	 *  frompc: the pc that did the call to ...
+	 *  selfpc: ... this location
+	 * the selfpc itself will need adjusting for the mcount call
+	 */
+	r1 = rets;
+	r0 = [fp + 4];
+	r1 += -MCOUNT_INSN_SIZE;
+
+	/* call the tracer */
+	call (p0);
+
+	/* restore state and get out of dodge */
+.Lfinish_trace:
+	rets = [sp++];
+	r1 = [sp++];
+	r0 = [sp++];
+	r2 = [sp++];
+
+.globl _ftrace_stub
+_ftrace_stub:
+	rts;
+ENDPROC(__mcount)
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+/* The prepare_ftrace_return() function is similar to the trace function
+ * except it takes a pointer to the location of the frompc.  This is so
+ * the prepare_ftrace_return() can hijack it temporarily for probing
+ * purposes.
+ */
+ENTRY(_ftrace_graph_caller)
+	/* save first/second function arg and the return register */
+	[--sp] = r0;
+	[--sp] = r1;
+	[--sp] = rets;
+
+	r0 = fp;
+	r1 = rets;
+	r0 += 4;
+	r1 += -MCOUNT_INSN_SIZE;
+	call _prepare_ftrace_return;
+
+	jump .Lfinish_trace;
+ENDPROC(_ftrace_graph_caller)
+
+/* Undo the rewrite caused by ftrace_graph_caller().  The common function
+ * ftrace_return_to_handler() will return the original rets so we can
+ * restore it and be on our way.
+ */
+ENTRY(_return_to_handler)
+	/* make sure original return values are saved */
+	[--sp] = p0;
+	[--sp] = r0;
+	[--sp] = r1;
+
+	/* get original return address */
+	call _ftrace_return_to_handler;
+	rets = r0;
+
+	/* anomaly 05000371 - make sure we have at least three instructions
+	 * between rets setting and the return
+	 */
+	r1 = [sp++];
+	r0 = [sp++];
+	p0 = [sp++];
+	rts;
+ENDPROC(_return_to_handler)
+#endif