2 * Code for tracing calls in Linux kernel.
3 * Copyright (C) 2009-2016 Helge Deller <deller@gmx.de>
5 * based on code for x86 which is:
6 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
8 * future possible enhancements:
9 * - add CONFIG_DYNAMIC_FTRACE
10 * - add CONFIG_STACK_TRACER
13 #include <linux/init.h>
14 #include <linux/ftrace.h>
16 #include <asm/assembly.h>
17 #include <asm/sections.h>
18 #include <asm/ftrace.h>
21 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
23 * Hook the return address and push it in the stack of return addrs
24 * in current thread info.
26 static void prepare_ftrace_return(unsigned long *parent
, unsigned long self_addr
)
29 struct ftrace_graph_ent trace
;
30 extern int parisc_return_to_handler
;
32 if (unlikely(ftrace_graph_is_dead()))
35 if (unlikely(atomic_read(¤t
->tracing_graph_pause
)))
40 trace
.func
= self_addr
;
41 trace
.depth
= current
->curr_ret_stack
+ 1;
43 /* Only trace if the calling function expects to */
44 if (!ftrace_graph_entry(&trace
))
47 if (ftrace_push_return_trace(old
, self_addr
, &trace
.depth
,
51 /* activate parisc_return_to_handler() as return point */
52 *parent
= (unsigned long) &parisc_return_to_handler
;
54 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
56 void notrace
ftrace_function_trampoline(unsigned long parent
,
57 unsigned long self_addr
,
58 unsigned long org_sp_gr3
)
60 extern ftrace_func_t ftrace_trace_function
; /* depends on CONFIG_DYNAMIC_FTRACE */
61 extern int ftrace_graph_entry_stub(struct ftrace_graph_ent
*trace
);
63 if (ftrace_trace_function
!= ftrace_stub
) {
64 /* struct ftrace_ops *op, struct pt_regs *regs); */
65 ftrace_trace_function(parent
, self_addr
, NULL
, NULL
);
69 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
70 if (ftrace_graph_return
!= (trace_func_graph_ret_t
) ftrace_stub
||
71 ftrace_graph_entry
!= ftrace_graph_entry_stub
) {
72 unsigned long *parent_rp
;
74 /* calculate pointer to %rp in stack */
75 parent_rp
= (unsigned long *) (org_sp_gr3
- RP_OFFSET
);
76 /* sanity check: parent_rp should hold parent */
77 if (*parent_rp
!= parent
)
80 prepare_ftrace_return(parent_rp
, self_addr
);