x86, bts, ftrace: adapt the hw-branch-tracer to the ds.c interface
Impact: restructure code, cleanup
Remove BTS bits from the hw-branch-tracer (renamed from bts-tracer) and
use the ds interface.
Signed-off-by: Markus Metzger <markut.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/trace_hw_branches.c b/kernel/trace/trace_hw_branches.c
new file mode 100644
index 0000000..ee29e01
--- /dev/null
+++ b/kernel/trace/trace_hw_branches.c
@@ -0,0 +1,205 @@
+/*
+ * h/w branch tracer for x86 based on bts
+ *
+ * Copyright (C) 2008 Markus Metzger <markus.t.metzger@gmail.com>
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/debugfs.h>
+#include <linux/ftrace.h>
+#include <linux/kallsyms.h>
+
+#include <asm/ds.h>
+
+#include "trace.h"
+
+
+#define SIZEOF_BTS (1 << 13)
+
+static DEFINE_PER_CPU(struct bts_tracer *, tracer);
+static DEFINE_PER_CPU(unsigned char[SIZEOF_BTS], buffer);
+
+#define this_tracer per_cpu(tracer, smp_processor_id())
+#define this_buffer per_cpu(buffer, smp_processor_id())
+
+
+static void bts_trace_reset(struct trace_array *tr)
+{
+ int cpu;
+
+ tr->time_start = ftrace_now(tr->cpu);
+
+ for_each_online_cpu(cpu)
+ tracing_reset(tr, cpu);
+}
+
+static void bts_trace_start_cpu(void *arg)
+{
+ if (this_tracer)
+ ds_release_bts(this_tracer);
+
+ this_tracer =
+ ds_request_bts(/* task = */ NULL, this_buffer, SIZEOF_BTS,
+ /* ovfl = */ NULL, /* th = */ (size_t)-1,
+ BTS_KERNEL);
+ if (IS_ERR(this_tracer)) {
+ this_tracer = NULL;
+ return;
+ }
+}
+
+static void bts_trace_start(struct trace_array *tr)
+{
+ int cpu;
+
+ bts_trace_reset(tr);
+
+ for_each_cpu_mask(cpu, cpu_possible_map)
+ smp_call_function_single(cpu, bts_trace_start_cpu, NULL, 1);
+}
+
+static void bts_trace_stop_cpu(void *arg)
+{
+ if (this_tracer) {
+ ds_release_bts(this_tracer);
+ this_tracer = NULL;
+ }
+}
+
+static void bts_trace_stop(struct trace_array *tr)
+{
+ int cpu;
+
+ for_each_cpu_mask(cpu, cpu_possible_map)
+ smp_call_function_single(cpu, bts_trace_stop_cpu, NULL, 1);
+}
+
+static int bts_trace_init(struct trace_array *tr)
+{
+ bts_trace_reset(tr);
+ bts_trace_start(tr);
+
+ return 0;
+}
+
+static void bts_trace_print_header(struct seq_file *m)
+{
+ seq_puts(m,
+ "# CPU# FROM TO FUNCTION\n");
+ seq_puts(m,
+ "# | | | |\n");
+}
+
+static enum print_line_t bts_trace_print_line(struct trace_iterator *iter)
+{
+ struct trace_entry *entry = iter->ent;
+ struct trace_seq *seq = &iter->seq;
+ struct hw_branch_entry *it;
+
+ trace_assign_type(it, entry);
+
+ if (entry->type == TRACE_HW_BRANCHES) {
+ if (trace_seq_printf(seq, "%4d ", entry->cpu) &&
+ trace_seq_printf(seq, "0x%016llx -> 0x%016llx ",
+ it->from, it->to) &&
+ (!it->from ||
+ seq_print_ip_sym(seq, it->from, /* sym_flags = */ 0)) &&
+ trace_seq_printf(seq, "\n"))
+ return TRACE_TYPE_HANDLED;
+ return TRACE_TYPE_PARTIAL_LINE;;
+ }
+ return TRACE_TYPE_UNHANDLED;
+}
+
+void trace_hw_branch(struct trace_array *tr, u64 from, u64 to)
+{
+ struct ring_buffer_event *event;
+ struct hw_branch_entry *entry;
+ unsigned long irq;
+
+ event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), &irq);
+ if (!event)
+ return;
+ entry = ring_buffer_event_data(event);
+ tracing_generic_entry_update(&entry->ent, 0, from);
+ entry->ent.type = TRACE_HW_BRANCHES;
+ entry->ent.cpu = smp_processor_id();
+ entry->from = from;
+ entry->to = to;
+ ring_buffer_unlock_commit(tr->buffer, event, irq);
+}
+
+static void trace_bts_at(struct trace_array *tr,
+ const struct bts_trace *trace, void *at)
+{
+ struct bts_struct bts;
+ int err = 0;
+
+ WARN_ON_ONCE(!trace->read);
+ if (!trace->read)
+ return;
+
+ err = trace->read(this_tracer, at, &bts);
+ if (err < 0)
+ return;
+
+ switch (bts.qualifier) {
+ case BTS_BRANCH:
+ trace_hw_branch(tr, bts.variant.lbr.from, bts.variant.lbr.to);
+ break;
+ }
+}
+
+static void trace_bts_cpu(void *arg)
+{
+ struct trace_array *tr = (struct trace_array *) arg;
+ const struct bts_trace *trace;
+ unsigned char *at;
+
+ if (!this_tracer)
+ return;
+
+ ds_suspend_bts(this_tracer);
+ trace = ds_read_bts(this_tracer);
+ if (!trace)
+ goto out;
+
+ for (at = trace->ds.top; (void *)at < trace->ds.end;
+ at += trace->ds.size)
+ trace_bts_at(tr, trace, at);
+
+ for (at = trace->ds.begin; (void *)at < trace->ds.top;
+ at += trace->ds.size)
+ trace_bts_at(tr, trace, at);
+
+out:
+ ds_resume_bts(this_tracer);
+}
+
+static void trace_bts_prepare(struct trace_iterator *iter)
+{
+ int cpu;
+
+ for_each_cpu_mask(cpu, cpu_possible_map)
+ smp_call_function_single(cpu, trace_bts_cpu, iter->tr, 1);
+}
+
+struct tracer bts_tracer __read_mostly =
+{
+ .name = "hw-branch-tracer",
+ .init = bts_trace_init,
+ .reset = bts_trace_stop,
+ .print_header = bts_trace_print_header,
+ .print_line = bts_trace_print_line,
+ .start = bts_trace_start,
+ .stop = bts_trace_stop,
+ .open = trace_bts_prepare
+};
+
+__init static int init_bts_trace(void)
+{
+ return register_tracer(&bts_tracer);
+}
+device_initcall(init_bts_trace);