x86, bts, ftrace: adapt the hw-branch-tracer to the ds.c interface
[linux-2.6.git] / 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_reset(struct trace_array *tr)
29 {
30         int cpu;
31
32         tr->time_start = ftrace_now(tr->cpu);
33
34         for_each_online_cpu(cpu)
35                 tracing_reset(tr, cpu);
36 }
37
38 static void bts_trace_start_cpu(void *arg)
39 {
40         if (this_tracer)
41                 ds_release_bts(this_tracer);
42
43         this_tracer =
44                 ds_request_bts(/* task = */ NULL, this_buffer, SIZEOF_BTS,
45                                /* ovfl = */ NULL, /* th = */ (size_t)-1,
46                                BTS_KERNEL);
47         if (IS_ERR(this_tracer)) {
48                 this_tracer = NULL;
49                 return;
50         }
51 }
52
53 static void bts_trace_start(struct trace_array *tr)
54 {
55         int cpu;
56
57         bts_trace_reset(tr);
58
59         for_each_cpu_mask(cpu, cpu_possible_map)
60                 smp_call_function_single(cpu, bts_trace_start_cpu, NULL, 1);
61 }
62
63 static void bts_trace_stop_cpu(void *arg)
64 {
65         if (this_tracer) {
66                 ds_release_bts(this_tracer);
67                 this_tracer = NULL;
68         }
69 }
70
71 static void bts_trace_stop(struct trace_array *tr)
72 {
73         int cpu;
74
75         for_each_cpu_mask(cpu, cpu_possible_map)
76                 smp_call_function_single(cpu, bts_trace_stop_cpu, NULL, 1);
77 }
78
79 static int bts_trace_init(struct trace_array *tr)
80 {
81         bts_trace_reset(tr);
82         bts_trace_start(tr);
83
84         return 0;
85 }
86
87 static void bts_trace_print_header(struct seq_file *m)
88 {
89         seq_puts(m,
90                  "# CPU#        FROM                   TO         FUNCTION\n");
91         seq_puts(m,
92                  "#  |           |                     |             |\n");
93 }
94
95 static enum print_line_t bts_trace_print_line(struct trace_iterator *iter)
96 {
97         struct trace_entry *entry = iter->ent;
98         struct trace_seq *seq = &iter->seq;
99         struct hw_branch_entry *it;
100
101         trace_assign_type(it, entry);
102
103         if (entry->type == TRACE_HW_BRANCHES) {
104                 if (trace_seq_printf(seq, "%4d  ", entry->cpu) &&
105                     trace_seq_printf(seq, "0x%016llx -> 0x%016llx ",
106                                      it->from, it->to) &&
107                     (!it->from ||
108                      seq_print_ip_sym(seq, it->from, /* sym_flags = */ 0)) &&
109                     trace_seq_printf(seq, "\n"))
110                         return TRACE_TYPE_HANDLED;
111                 return TRACE_TYPE_PARTIAL_LINE;;
112         }
113         return TRACE_TYPE_UNHANDLED;
114 }
115
116 void trace_hw_branch(struct trace_array *tr, u64 from, u64 to)
117 {
118         struct ring_buffer_event *event;
119         struct hw_branch_entry *entry;
120         unsigned long irq;
121
122         event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), &irq);
123         if (!event)
124                 return;
125         entry   = ring_buffer_event_data(event);
126         tracing_generic_entry_update(&entry->ent, 0, from);
127         entry->ent.type = TRACE_HW_BRANCHES;
128         entry->ent.cpu = smp_processor_id();
129         entry->from = from;
130         entry->to   = to;
131         ring_buffer_unlock_commit(tr->buffer, event, irq);
132 }
133
134 static void trace_bts_at(struct trace_array *tr,
135                          const struct bts_trace *trace, void *at)
136 {
137         struct bts_struct bts;
138         int err = 0;
139
140         WARN_ON_ONCE(!trace->read);
141         if (!trace->read)
142                 return;
143
144         err = trace->read(this_tracer, at, &bts);
145         if (err < 0)
146                 return;
147
148         switch (bts.qualifier) {
149         case BTS_BRANCH:
150                 trace_hw_branch(tr, bts.variant.lbr.from, bts.variant.lbr.to);
151                 break;
152         }
153 }
154
155 static void trace_bts_cpu(void *arg)
156 {
157         struct trace_array *tr = (struct trace_array *) arg;
158         const struct bts_trace *trace;
159         unsigned char *at;
160
161         if (!this_tracer)
162                 return;
163
164         ds_suspend_bts(this_tracer);
165         trace = ds_read_bts(this_tracer);
166         if (!trace)
167                 goto out;
168
169         for (at = trace->ds.top; (void *)at < trace->ds.end;
170              at += trace->ds.size)
171                 trace_bts_at(tr, trace, at);
172
173         for (at = trace->ds.begin; (void *)at < trace->ds.top;
174              at += trace->ds.size)
175                 trace_bts_at(tr, trace, at);
176
177 out:
178         ds_resume_bts(this_tracer);
179 }
180
181 static void trace_bts_prepare(struct trace_iterator *iter)
182 {
183         int cpu;
184
185         for_each_cpu_mask(cpu, cpu_possible_map)
186                 smp_call_function_single(cpu, trace_bts_cpu, iter->tr, 1);
187 }
188
189 struct tracer bts_tracer __read_mostly =
190 {
191         .name           = "hw-branch-tracer",
192         .init           = bts_trace_init,
193         .reset          = bts_trace_stop,
194         .print_header   = bts_trace_print_header,
195         .print_line     = bts_trace_print_line,
196         .start          = bts_trace_start,
197         .stop           = bts_trace_stop,
198         .open           = trace_bts_prepare
199 };
200
201 __init static int init_bts_trace(void)
202 {
203         return register_tracer(&bts_tracer);
204 }
205 device_initcall(init_bts_trace);