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>
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 3271916..d14fe49 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -831,6 +831,40 @@
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,
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index c460e85..0ef9ef7 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -5,6 +5,7 @@
#include <asm/atomic.h>
#include <linux/sched.h>
#include <linux/clocksource.h>
+#include <linux/mmiotrace.h>
enum trace_type {
__TRACE_FIRST_TYPE = 0,
@@ -14,6 +15,8 @@
TRACE_WAKE,
TRACE_STACK,
TRACE_SPECIAL,
+ TRACE_MMIO_RW,
+ TRACE_MMIO_MAP,
__TRACE_LAST_TYPE
};
@@ -75,6 +78,8 @@
struct ctx_switch_entry ctx;
struct special_entry special;
struct stack_entry stack;
+ struct mmiotrace_rw mmiorw;
+ struct mmiotrace_map mmiomap;
};
};
@@ -255,6 +260,15 @@
extern int DYN_FTRACE_TEST_NAME(void);
#endif
+#ifdef CONFIG_MMIOTRACE
+extern void __trace_mmiotrace_rw(struct trace_array *tr,
+ struct trace_array_cpu *data,
+ struct mmiotrace_rw *rw);
+extern void __trace_mmiotrace_map(struct trace_array *tr,
+ struct trace_array_cpu *data,
+ struct mmiotrace_map *map);
+#endif
+
#ifdef CONFIG_FTRACE_STARTUP_TEST
#ifdef CONFIG_FTRACE
extern int trace_selftest_startup_function(struct tracer *trace,
diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
index e4dd03cc..3a12b1a 100644
--- a/kernel/trace/trace_mmiotrace.c
+++ b/kernel/trace/trace_mmiotrace.c
@@ -11,19 +11,26 @@
#include "trace.h"
-extern void
-__trace_special(void *__tr, void *__data,
- unsigned long arg1, unsigned long arg2, unsigned long arg3);
-
static struct trace_array *mmio_trace_array;
+static void mmio_reset_data(struct trace_array *tr)
+{
+ int cpu;
+
+ tr->time_start = ftrace_now(tr->cpu);
+
+ for_each_online_cpu(cpu)
+ tracing_reset(tr->data[cpu]);
+}
static void mmio_trace_init(struct trace_array *tr)
{
pr_debug("in %s\n", __func__);
mmio_trace_array = tr;
- if (tr->ctrl)
+ if (tr->ctrl) {
+ mmio_reset_data(tr);
enable_mmiotrace();
+ }
}
static void mmio_trace_reset(struct trace_array *tr)
@@ -31,15 +38,110 @@
pr_debug("in %s\n", __func__);
if (tr->ctrl)
disable_mmiotrace();
+ mmio_reset_data(tr);
+ mmio_trace_array = NULL;
}
static void mmio_trace_ctrl_update(struct trace_array *tr)
{
pr_debug("in %s\n", __func__);
- if (tr->ctrl)
+ if (tr->ctrl) {
+ mmio_reset_data(tr);
enable_mmiotrace();
- else
+ } else {
disable_mmiotrace();
+ }
+}
+
+/* XXX: This is not called for trace_pipe file! */
+void mmio_print_header(struct trace_iterator *iter)
+{
+ struct trace_seq *s = &iter->seq;
+ trace_seq_printf(s, "VERSION broken 20070824\n");
+ /* TODO: print /proc/bus/pci/devices contents as PCIDEV lines */
+}
+
+static int mmio_print_rw(struct trace_iterator *iter)
+{
+ struct trace_entry *entry = iter->ent;
+ struct mmiotrace_rw *rw = &entry->mmiorw;
+ struct trace_seq *s = &iter->seq;
+ unsigned long long t = ns2usecs(entry->t);
+ unsigned long usec_rem = do_div(t, 1000000ULL);
+ unsigned secs = (unsigned long)t;
+ int ret = 1;
+
+ switch (entry->mmiorw.opcode) {
+ case MMIO_READ:
+ ret = trace_seq_printf(s,
+ "R %d %lu.%06lu %d 0x%lx 0x%lx 0x%lx %d\n",
+ rw->width, secs, usec_rem, rw->map_id, rw->phys,
+ rw->value, rw->pc, entry->pid);
+ break;
+ case MMIO_WRITE:
+ ret = trace_seq_printf(s,
+ "W %d %lu.%06lu %d 0x%lx 0x%lx 0x%lx %d\n",
+ rw->width, secs, usec_rem, rw->map_id, rw->phys,
+ rw->value, rw->pc, entry->pid);
+ break;
+ case MMIO_UNKNOWN_OP:
+ ret = trace_seq_printf(s,
+ "UNKNOWN %lu.%06lu %d 0x%lx %02x,%02x,%02x 0x%lx %d\n",
+ secs, usec_rem, rw->map_id, rw->phys,
+ (rw->value >> 16) & 0xff, (rw->value >> 8) & 0xff,
+ (rw->value >> 0) & 0xff, rw->pc, entry->pid);
+ break;
+ default:
+ ret = trace_seq_printf(s, "rw what?\n");
+ break;
+ }
+ if (ret)
+ return 1;
+ return 0;
+}
+
+static int mmio_print_map(struct trace_iterator *iter)
+{
+ struct trace_entry *entry = iter->ent;
+ struct mmiotrace_map *m = &entry->mmiomap;
+ struct trace_seq *s = &iter->seq;
+ unsigned long long t = ns2usecs(entry->t);
+ unsigned long usec_rem = do_div(t, 1000000ULL);
+ unsigned secs = (unsigned long)t;
+ int ret = 1;
+
+ switch (entry->mmiorw.opcode) {
+ case MMIO_PROBE:
+ ret = trace_seq_printf(s,
+ "MAP %lu.%06lu %d 0x%lx 0x%lx 0x%lx 0x%lx %d\n",
+ secs, usec_rem, m->map_id, m->phys, m->virt, m->len,
+ 0UL, entry->pid);
+ break;
+ case MMIO_UNPROBE:
+ ret = trace_seq_printf(s,
+ "UNMAP %lu.%06lu %d 0x%lx %d\n",
+ secs, usec_rem, m->map_id, 0UL, entry->pid);
+ break;
+ default:
+ ret = trace_seq_printf(s, "map what?\n");
+ break;
+ }
+ if (ret)
+ return 1;
+ return 0;
+}
+
+/* return 0 to abort printing without consuming current entry in pipe mode */
+static int mmio_print_line(struct trace_iterator *iter)
+{
+ switch (iter->ent->type) {
+ case TRACE_MMIO_RW:
+ return mmio_print_rw(iter);
+ case TRACE_MMIO_MAP:
+ return mmio_print_map(iter);
+ default:
+ return 1; /* ignore unknown entries */
+ }
}
static struct tracer mmio_tracer __read_mostly =
@@ -47,38 +149,31 @@
.name = "mmiotrace",
.init = mmio_trace_init,
.reset = mmio_trace_reset,
+ .open = mmio_print_header,
.ctrl_update = mmio_trace_ctrl_update,
+ .print_line = mmio_print_line,
};
__init static int init_mmio_trace(void)
{
- int ret = init_mmiotrace();
- if (ret)
- return ret;
return register_tracer(&mmio_tracer);
}
device_initcall(init_mmio_trace);
-void mmio_trace_record(u32 type, unsigned long addr, unsigned long arg)
+void mmio_trace_rw(struct mmiotrace_rw *rw)
{
struct trace_array *tr = mmio_trace_array;
struct trace_array_cpu *data = tr->data[smp_processor_id()];
+ __trace_mmiotrace_rw(tr, data, rw);
+}
- if (!current || current->pid == 0) {
- /*
- * XXX: This is a problem. We need to able to record, no
- * matter what. tracing_generic_entry_update() would crash.
- */
- static unsigned limit;
- if (limit++ < 12)
- pr_err("Error in %s: no current.\n", __func__);
- return;
- }
- if (!tr || !data) {
- static unsigned limit;
- if (limit++ < 12)
- pr_err("%s: no tr or data\n", __func__);
- return;
- }
- __trace_special(tr, data, type, addr, arg);
+void mmio_trace_mapping(struct mmiotrace_map *map)
+{
+ struct trace_array *tr = mmio_trace_array;
+ struct trace_array_cpu *data;
+
+ preempt_disable();
+ data = tr->data[smp_processor_id()];
+ __trace_mmiotrace_map(tr, data, map);
+ preempt_enable();
}
