1 files changed, 23 insertions, 123 deletions

diff --git a/arch/parisc/kernel/ftrace.c b/arch/parisc/kernel/ftrace.c
index 559d400f9385..b13f9ec6f294 100644
--- a/arch/parisc/kernel/ftrace.c
+++ b/arch/parisc/kernel/ftrace.c
@@ -1,6 +1,6 @@
 /*
  * Code for tracing calls in Linux kernel.
- * Copyright (C) 2009 Helge Deller <deller@gmx.de>
+ * Copyright (C) 2009-2016 Helge Deller <deller@gmx.de>
  *
  * based on code for x86 which is:
  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
@@ -13,104 +13,21 @@
 #include <linux/init.h>
 #include <linux/ftrace.h>
 
+#include <asm/assembly.h>
 #include <asm/sections.h>
 #include <asm/ftrace.h>
 
 
-
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-
-/* Add a function return address to the trace stack on thread info.*/
-static int push_return_trace(unsigned long ret, unsigned long long time,
-				unsigned long func, int *depth)
-{
-	int index;
-
-	if (!current->ret_stack)
-		return -EBUSY;
-
-	/* The return trace stack is full */
-	if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
-		atomic_inc(&current->trace_overrun);
-		return -EBUSY;
-	}
-
-	index = ++current->curr_ret_stack;
-	barrier();
-	current->ret_stack[index].ret = ret;
-	current->ret_stack[index].func = func;
-	current->ret_stack[index].calltime = time;
-	*depth = index;
-
-	return 0;
-}
-
-/* Retrieve a function return address to the trace stack on thread info.*/
-static void pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
-{
-	int index;
-
-	index = current->curr_ret_stack;
-
-	if (unlikely(index < 0)) {
-		ftrace_graph_stop();
-		WARN_ON(1);
-		/* Might as well panic, otherwise we have no where to go */
-		*ret = (unsigned long)
-			dereference_function_descriptor(&panic);
-		return;
-	}
-
-	*ret = current->ret_stack[index].ret;
-	trace->func = current->ret_stack[index].func;
-	trace->calltime = current->ret_stack[index].calltime;
-	trace->overrun = atomic_read(&current->trace_overrun);
-	trace->depth = index;
-	barrier();
-	current->curr_ret_stack--;
-
-}
-
-/*
- * Send the trace to the ring-buffer.
- * @return the original return address.
- */
-unsigned long ftrace_return_to_handler(unsigned long retval0,
-				       unsigned long retval1)
-{
-	struct ftrace_graph_ret trace;
-	unsigned long ret;
-
-	pop_return_trace(&trace, &ret);
-	trace.rettime = local_clock();
-	ftrace_graph_return(&trace);
-
-	if (unlikely(!ret)) {
-		ftrace_graph_stop();
-		WARN_ON(1);
-		/* Might as well panic. What else to do? */
-		ret = (unsigned long)
-			dereference_function_descriptor(&panic);
-	}
-
-	/* HACK: we hand over the old functions' return values
-	   in %r23 and %r24. Assembly in entry.S will take care
-	   and move those to their final registers %ret0 and %ret1 */
-	asm( "copy %0, %%r23 \n\t"
-	     "copy %1, %%r24 \n" : : "r" (retval0), "r" (retval1) );
-
-	return ret;
-}
-
 /*
  * Hook the return address and push it in the stack of return addrs
  * in current thread info.
  */
-void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
+static void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
 {
 	unsigned long old;
-	unsigned long long calltime;
 	struct ftrace_graph_ent trace;
+	extern int parisc_return_to_handler;
 
 	if (unlikely(ftrace_graph_is_dead()))
 		return;
@@ -119,64 +36,47 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
 		return;
 
 	old = *parent;
-	*parent = (unsigned long)
-		  dereference_function_descriptor(&return_to_handler);
 
-	if (unlikely(!__kernel_text_address(old))) {
-		ftrace_graph_stop();
-		*parent = old;
-		WARN_ON(1);
-		return;
-	}
-
-	calltime = local_clock();
+	trace.func = self_addr;
+	trace.depth = current->curr_ret_stack + 1;
 
-	if (push_return_trace(old, calltime,
-				self_addr, &trace.depth) == -EBUSY) {
-		*parent = old;
+	/* Only trace if the calling function expects to */
+	if (!ftrace_graph_entry(&trace))
 		return;
-	}
 
-	trace.func = self_addr;
+        if (ftrace_push_return_trace(old, self_addr, &trace.depth,
+			0 ) == -EBUSY)
+                return;
 
-	/* Only trace if the calling function expects to */
-	if (!ftrace_graph_entry(&trace)) {
-		current->curr_ret_stack--;
-		*parent = old;
-	}
+	/* activate parisc_return_to_handler() as return point */
+	*parent = (unsigned long) &parisc_return_to_handler;
 }
-
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
-
-void ftrace_function_trampoline(unsigned long parent,
+void notrace ftrace_function_trampoline(unsigned long parent,
 				unsigned long self_addr,
 				unsigned long org_sp_gr3)
 {
-	extern ftrace_func_t ftrace_trace_function;
+	extern ftrace_func_t ftrace_trace_function;  /* depends on CONFIG_DYNAMIC_FTRACE */
+	extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);
 
 	if (ftrace_trace_function != ftrace_stub) {
-		ftrace_trace_function(parent, self_addr);
+		/* struct ftrace_ops *op, struct pt_regs *regs); */
+		ftrace_trace_function(parent, self_addr, NULL, NULL);
 		return;
 	}
+
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	if (ftrace_graph_entry && ftrace_graph_return) {
-		unsigned long sp;
+	if (ftrace_graph_return != (trace_func_graph_ret_t) ftrace_stub ||
+		ftrace_graph_entry != ftrace_graph_entry_stub) {
 		unsigned long *parent_rp;
 
-                asm volatile ("copy %%r30, %0" : "=r"(sp));
-		/* sanity check: is stack pointer which we got from
-		   assembler function in entry.S in a reasonable
-		   range compared to current stack pointer? */
-		if ((sp - org_sp_gr3) > 0x400)
-			return;
-
 		/* calculate pointer to %rp in stack */
-		parent_rp = (unsigned long *) org_sp_gr3 - 0x10;
+		parent_rp = (unsigned long *) (org_sp_gr3 - RP_OFFSET);
 		/* sanity check: parent_rp should hold parent */
 		if (*parent_rp != parent)
 			return;
-		
+
 		prepare_ftrace_return(parent_rp, self_addr);
 		return;
 	}