24ea837eac5bebc4f55018e8940386bb322636bc
[linux-2.6.git] / arch / sh / kernel / perf_callchain.c
1 /*
2  * Performance event callchain support - SuperH architecture code
3  *
4  * Copyright (C) 2009  Paul Mundt
5  *
6  * This file is subject to the terms and conditions of the GNU General Public
7  * License.  See the file "COPYING" in the main directory of this archive
8  * for more details.
9  */
10 #include <linux/kernel.h>
11 #include <linux/sched.h>
12 #include <linux/perf_event.h>
13 #include <linux/percpu.h>
14 #include <asm/unwinder.h>
15 #include <asm/ptrace.h>
16
17 static inline void callchain_store(struct perf_callchain_entry *entry, u64 ip)
18 {
19         if (entry->nr < PERF_MAX_STACK_DEPTH)
20                 entry->ip[entry->nr++] = ip;
21 }
22
23 static void callchain_warning(void *data, char *msg)
24 {
25 }
26
27 static void
28 callchain_warning_symbol(void *data, char *msg, unsigned long symbol)
29 {
30 }
31
32 static int callchain_stack(void *data, char *name)
33 {
34         return 0;
35 }
36
37 static void callchain_address(void *data, unsigned long addr, int reliable)
38 {
39         struct perf_callchain_entry *entry = data;
40
41         if (reliable)
42                 callchain_store(entry, addr);
43 }
44
45 static const struct stacktrace_ops callchain_ops = {
46         .warning        = callchain_warning,
47         .warning_symbol = callchain_warning_symbol,
48         .stack          = callchain_stack,
49         .address        = callchain_address,
50 };
51
52 static void
53 perf_callchain_kernel(struct pt_regs *regs, struct perf_callchain_entry *entry)
54 {
55         callchain_store(entry, PERF_CONTEXT_KERNEL);
56         callchain_store(entry, regs->pc);
57
58         unwind_stack(NULL, regs, NULL, &callchain_ops, entry);
59 }
60
61 static void
62 perf_do_callchain(struct pt_regs *regs, struct perf_callchain_entry *entry)
63 {
64         int is_user;
65
66         if (!regs)
67                 return;
68
69         is_user = user_mode(regs);
70
71         if (!current || current->pid == 0)
72                 return;
73
74         if (is_user && current->state != TASK_RUNNING)
75                 return;
76
77         /*
78          * Only the kernel side is implemented for now.
79          */
80         if (!is_user)
81                 perf_callchain_kernel(regs, entry);
82 }
83
84 /*
85  * No need for separate IRQ and NMI entries.
86  */
87 static DEFINE_PER_CPU(struct perf_callchain_entry, callchain);
88
89 struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
90 {
91         struct perf_callchain_entry *entry = &__get_cpu_var(callchain);
92
93         entry->nr = 0;
94
95         perf_do_callchain(regs, entry);
96
97         return entry;
98 }