Linux 4.8-rc8
[linux/fpc-iii.git] / arch / parisc / kernel / ftrace.c
bloba828a0adf52c0b19d14eb12219bf718c3cf37704
1 /*
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 #define __hot __attribute__ ((__section__ (".text.hot")))
23 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
25 * Hook the return address and push it in the stack of return addrs
26 * in current thread info.
28 static void __hot prepare_ftrace_return(unsigned long *parent,
29 unsigned long self_addr)
31 unsigned long old;
32 struct ftrace_graph_ent trace;
33 extern int parisc_return_to_handler;
35 if (unlikely(ftrace_graph_is_dead()))
36 return;
38 if (unlikely(atomic_read(&current->tracing_graph_pause)))
39 return;
41 old = *parent;
43 trace.func = self_addr;
44 trace.depth = current->curr_ret_stack + 1;
46 /* Only trace if the calling function expects to */
47 if (!ftrace_graph_entry(&trace))
48 return;
50 if (ftrace_push_return_trace(old, self_addr, &trace.depth,
51 0 ) == -EBUSY)
52 return;
54 /* activate parisc_return_to_handler() as return point */
55 *parent = (unsigned long) &parisc_return_to_handler;
57 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
59 void notrace __hot ftrace_function_trampoline(unsigned long parent,
60 unsigned long self_addr,
61 unsigned long org_sp_gr3)
63 extern ftrace_func_t ftrace_trace_function; /* depends on CONFIG_DYNAMIC_FTRACE */
64 extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);
66 if (ftrace_trace_function != ftrace_stub) {
67 /* struct ftrace_ops *op, struct pt_regs *regs); */
68 ftrace_trace_function(parent, self_addr, NULL, NULL);
69 return;
72 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
73 if (ftrace_graph_return != (trace_func_graph_ret_t) ftrace_stub ||
74 ftrace_graph_entry != ftrace_graph_entry_stub) {
75 unsigned long *parent_rp;
77 /* calculate pointer to %rp in stack */
78 parent_rp = (unsigned long *) (org_sp_gr3 - RP_OFFSET);
79 /* sanity check: parent_rp should hold parent */
80 if (*parent_rp != parent)
81 return;
83 prepare_ftrace_return(parent_rp, self_addr);
84 return;
86 #endif