Merge git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-next
[linux-2.6] / kernel / trace / trace_hw_branches.c
1 /*
2  * h/w branch tracer for x86 based on bts
3  *
4  * Copyright (C) 2008 Markus Metzger <markus.t.metzger@gmail.com>
5  *
6  */
7
8 #include <linux/module.h>
9 #include <linux/fs.h>
10 #include <linux/debugfs.h>
11 #include <linux/ftrace.h>
12 #include <linux/kallsyms.h>
13
14 #include <asm/ds.h>
15
16 #include "trace.h"
17
18
19 #define SIZEOF_BTS (1 << 13)
20
21 static DEFINE_PER_CPU(struct bts_tracer *, tracer);
22 static DEFINE_PER_CPU(unsigned char[SIZEOF_BTS], buffer);
23
24 #define this_tracer per_cpu(tracer, smp_processor_id())
25 #define this_buffer per_cpu(buffer, smp_processor_id())
26
27
28 static void bts_trace_start_cpu(void *arg)
29 {
30         if (this_tracer)
31                 ds_release_bts(this_tracer);
32
33         this_tracer =
34                 ds_request_bts(/* task = */ NULL, this_buffer, SIZEOF_BTS,
35                                /* ovfl = */ NULL, /* th = */ (size_t)-1,
36                                BTS_KERNEL);
37         if (IS_ERR(this_tracer)) {
38                 this_tracer = NULL;
39                 return;
40         }
41 }
42
43 static void bts_trace_start(struct trace_array *tr)
44 {
45         int cpu;
46
47         tracing_reset_online_cpus(tr);
48
49         for_each_cpu_mask(cpu, cpu_possible_map)
50                 smp_call_function_single(cpu, bts_trace_start_cpu, NULL, 1);
51 }
52
53 static void bts_trace_stop_cpu(void *arg)
54 {
55         if (this_tracer) {
56                 ds_release_bts(this_tracer);
57                 this_tracer = NULL;
58         }
59 }
60
61 static void bts_trace_stop(struct trace_array *tr)
62 {
63         int cpu;
64
65         for_each_cpu_mask(cpu, cpu_possible_map)
66                 smp_call_function_single(cpu, bts_trace_stop_cpu, NULL, 1);
67 }
68
69 static int bts_trace_init(struct trace_array *tr)
70 {
71         tracing_reset_online_cpus(tr);
72         bts_trace_start(tr);
73
74         return 0;
75 }
76
77 static void bts_trace_print_header(struct seq_file *m)
78 {
79         seq_puts(m,
80                  "# CPU#        FROM                   TO         FUNCTION\n");
81         seq_puts(m,
82                  "#  |           |                     |             |\n");
83 }
84
85 static enum print_line_t bts_trace_print_line(struct trace_iterator *iter)
86 {
87         struct trace_entry *entry = iter->ent;
88         struct trace_seq *seq = &iter->seq;
89         struct hw_branch_entry *it;
90
91         trace_assign_type(it, entry);
92
93         if (entry->type == TRACE_HW_BRANCHES) {
94                 if (trace_seq_printf(seq, "%4d  ", entry->cpu) &&
95                     trace_seq_printf(seq, "0x%016llx -> 0x%016llx ",
96                                      it->from, it->to) &&
97                     (!it->from ||
98                      seq_print_ip_sym(seq, it->from, /* sym_flags = */ 0)) &&
99                     trace_seq_printf(seq, "\n"))
100                         return TRACE_TYPE_HANDLED;
101                 return TRACE_TYPE_PARTIAL_LINE;;
102         }
103         return TRACE_TYPE_UNHANDLED;
104 }
105
106 void trace_hw_branch(struct trace_array *tr, u64 from, u64 to)
107 {
108         struct ring_buffer_event *event;
109         struct hw_branch_entry *entry;
110         unsigned long irq;
111
112         event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), &irq);
113         if (!event)
114                 return;
115         entry   = ring_buffer_event_data(event);
116         tracing_generic_entry_update(&entry->ent, 0, from);
117         entry->ent.type = TRACE_HW_BRANCHES;
118         entry->ent.cpu = smp_processor_id();
119         entry->from = from;
120         entry->to   = to;
121         ring_buffer_unlock_commit(tr->buffer, event, irq);
122 }
123
124 static void trace_bts_at(struct trace_array *tr,
125                          const struct bts_trace *trace, void *at)
126 {
127         struct bts_struct bts;
128         int err = 0;
129
130         WARN_ON_ONCE(!trace->read);
131         if (!trace->read)
132                 return;
133
134         err = trace->read(this_tracer, at, &bts);
135         if (err < 0)
136                 return;
137
138         switch (bts.qualifier) {
139         case BTS_BRANCH:
140                 trace_hw_branch(tr, bts.variant.lbr.from, bts.variant.lbr.to);
141                 break;
142         }
143 }
144
145 static void trace_bts_cpu(void *arg)
146 {
147         struct trace_array *tr = (struct trace_array *) arg;
148         const struct bts_trace *trace;
149         unsigned char *at;
150
151         if (!this_tracer)
152                 return;
153
154         ds_suspend_bts(this_tracer);
155         trace = ds_read_bts(this_tracer);
156         if (!trace)
157                 goto out;
158
159         for (at = trace->ds.top; (void *)at < trace->ds.end;
160              at += trace->ds.size)
161                 trace_bts_at(tr, trace, at);
162
163         for (at = trace->ds.begin; (void *)at < trace->ds.top;
164              at += trace->ds.size)
165                 trace_bts_at(tr, trace, at);
166
167 out:
168         ds_resume_bts(this_tracer);
169 }
170
171 static void trace_bts_prepare(struct trace_iterator *iter)
172 {
173         int cpu;
174
175         for_each_cpu_mask(cpu, cpu_possible_map)
176                 smp_call_function_single(cpu, trace_bts_cpu, iter->tr, 1);
177 }
178
179 struct tracer bts_tracer __read_mostly =
180 {
181         .name           = "hw-branch-tracer",
182         .init           = bts_trace_init,
183         .reset          = bts_trace_stop,
184         .print_header   = bts_trace_print_header,
185         .print_line     = bts_trace_print_line,
186         .start          = bts_trace_start,
187         .stop           = bts_trace_stop,
188         .open           = trace_bts_prepare
189 };
190
191 __init static int init_bts_trace(void)
192 {
193         return register_tracer(&bts_tracer);
194 }
195 device_initcall(init_bts_trace);