ftrace: mmiotrace, updates

here is a patch that makes mmiotrace work almost well within the tracing
framework. The patch applies on top of my previous patch. I have my own
output formatting in place now.

Summary of changes:
- fix the NULL dereference that was due to not calling tracing_reset()
- add print_line() callback into struct tracer
- implement print_line() for mmiotrace, producing up-to-spec text
- add my output header, but that is not really called in the right place
- rewrote the main structs in mmiotrace
- added two new trace entry types: TRACE_MMIO_RW and TRACE_MMIO_MAP
- made some functions in trace.c non-static
- check current==NULL in tracing_generic_entry_update()
- fix(?) comparison in trace_seq_printf()

Things seem to work fine except a few issues. Markers (text lines injected
into mmiotrace log) are missing, I did not feel hacking them in before we
have variable length entries. My output header is printed only for 'trace'
file, but not 'trace_pipe'. For some reason, despite my quick fix,
iter->trace is NULL in print_trace_line() when called from 'trace_pipe'
file, which means I don't get proper output formatting.

I only tried by loading nouveau.ko, which just detects the card, and that
is traced fine. I didn't try further. Map, two reads and unmap. Works
perfectly.

I am missing the information about overflows, I'd prefer to have a
counter for lost events. I didn't try, but I guess currently there is no
way of knowning when it overflows?

So, not too far from being fully operational, it seems :-)
And looking at the diffstat, there also is some 700-900 lines of user space
code that just became obsolete.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 34 insertions, 0 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 3271916ff033..d14fe49e9638 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -831,6 +831,40 @@ ftrace(struct trace_array *tr, struct trace_array_cpu *data,
                 trace_function(tr, data, ip, parent_ip, flags);
 }
 
+#ifdef CONFIG_MMIOTRACE
+void __trace_mmiotrace_rw(struct trace_array *tr, struct trace_array_cpu *data,
+                                                struct mmiotrace_rw *rw)
+{
+        struct trace_entry *entry;
+        unsigned long irq_flags;
+
+        spin_lock_irqsave(&data->lock, irq_flags);
+        entry                   = tracing_get_trace_entry(tr, data);
+        tracing_generic_entry_update(entry, 0);
+        entry->type             = TRACE_MMIO_RW;
+        entry->mmiorw           = *rw;
+        spin_unlock_irqrestore(&data->lock, irq_flags);
+
+        trace_wake_up();
+}
+
+void __trace_mmiotrace_map(struct trace_array *tr, struct trace_array_cpu *data,
+                                                struct mmiotrace_map *map)
+{
+        struct trace_entry *entry;
+        unsigned long irq_flags;
+
+        spin_lock_irqsave(&data->lock, irq_flags);
+        entry                   = tracing_get_trace_entry(tr, data);
+        tracing_generic_entry_update(entry, 0);
+        entry->type             = TRACE_MMIO_MAP;
+        entry->mmiomap          = *map;
+        spin_unlock_irqrestore(&data->lock, irq_flags);
+
+        trace_wake_up();
+}
+#endif
+
 void __trace_stack(struct trace_array *tr,
                    struct trace_array_cpu *data,
                    unsigned long flags,