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-rw-r--r--kernel/trace/Kconfig25
-rw-r--r--kernel/trace/ftrace.c6
-rw-r--r--kernel/trace/trace_mmiotrace.c14
-rw-r--r--kernel/trace/trace_selftest.c19
4 files changed, 59 insertions, 5 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index e2a4ff6fc3a..34e707e5ab8 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -52,6 +52,7 @@ config FUNCTION_TRACER
depends on HAVE_FUNCTION_TRACER
depends on DEBUG_KERNEL
select FRAME_POINTER
+ select KALLSYMS
select TRACING
select CONTEXT_SWITCH_TRACER
help
@@ -238,6 +239,7 @@ config STACK_TRACER
depends on DEBUG_KERNEL
select FUNCTION_TRACER
select STACKTRACE
+ select KALLSYMS
help
This special tracer records the maximum stack footprint of the
kernel and displays it in debugfs/tracing/stack_trace.
@@ -302,4 +304,27 @@ config FTRACE_STARTUP_TEST
functioning properly. It will do tests on all the configured
tracers of ftrace.
+config MMIOTRACE
+ bool "Memory mapped IO tracing"
+ depends on HAVE_MMIOTRACE_SUPPORT && DEBUG_KERNEL && PCI
+ select TRACING
+ help
+ Mmiotrace traces Memory Mapped I/O access and is meant for
+ debugging and reverse engineering. It is called from the ioremap
+ implementation and works via page faults. Tracing is disabled by
+ default and can be enabled at run-time.
+
+ See Documentation/tracers/mmiotrace.txt.
+ If you are not helping to develop drivers, say N.
+
+config MMIOTRACE_TEST
+ tristate "Test module for mmiotrace"
+ depends on MMIOTRACE && m
+ help
+ This is a dumb module for testing mmiotrace. It is very dangerous
+ as it will write garbage to IO memory starting at a given address.
+ However, it should be safe to use on e.g. unused portion of VRAM.
+
+ Say N, unless you absolutely know what you are doing.
+
endmenu
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 9a236ffe2aa..fdf913dfc7e 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2033,7 +2033,7 @@ free:
static int start_graph_tracing(void)
{
struct ftrace_ret_stack **ret_stack_list;
- int ret;
+ int ret, cpu;
ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
sizeof(struct ftrace_ret_stack *),
@@ -2042,6 +2042,10 @@ static int start_graph_tracing(void)
if (!ret_stack_list)
return -ENOMEM;
+ /* The cpu_boot init_task->ret_stack will never be freed */
+ for_each_online_cpu(cpu)
+ ftrace_graph_init_task(idle_task(cpu));
+
do {
ret = alloc_retstack_tasklist(ret_stack_list);
} while (ret == -EAGAIN);
diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
index fffcb069f1d..80e503ef613 100644
--- a/kernel/trace/trace_mmiotrace.c
+++ b/kernel/trace/trace_mmiotrace.c
@@ -9,6 +9,7 @@
#include <linux/kernel.h>
#include <linux/mmiotrace.h>
#include <linux/pci.h>
+#include <asm/atomic.h>
#include "trace.h"
@@ -19,6 +20,7 @@ struct header_iter {
static struct trace_array *mmio_trace_array;
static bool overrun_detected;
static unsigned long prev_overruns;
+static atomic_t dropped_count;
static void mmio_reset_data(struct trace_array *tr)
{
@@ -121,11 +123,11 @@ static void mmio_close(struct trace_iterator *iter)
static unsigned long count_overruns(struct trace_iterator *iter)
{
- unsigned long cnt = 0;
+ unsigned long cnt = atomic_xchg(&dropped_count, 0);
unsigned long over = ring_buffer_overruns(iter->tr->buffer);
if (over > prev_overruns)
- cnt = over - prev_overruns;
+ cnt += over - prev_overruns;
prev_overruns = over;
return cnt;
}
@@ -310,8 +312,10 @@ static void __trace_mmiotrace_rw(struct trace_array *tr,
event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
&irq_flags);
- if (!event)
+ if (!event) {
+ atomic_inc(&dropped_count);
return;
+ }
entry = ring_buffer_event_data(event);
tracing_generic_entry_update(&entry->ent, 0, preempt_count());
entry->ent.type = TRACE_MMIO_RW;
@@ -338,8 +342,10 @@ static void __trace_mmiotrace_map(struct trace_array *tr,
event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
&irq_flags);
- if (!event)
+ if (!event) {
+ atomic_inc(&dropped_count);
return;
+ }
entry = ring_buffer_event_data(event);
tracing_generic_entry_update(&entry->ent, 0, preempt_count());
entry->ent.type = TRACE_MMIO_MAP;
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 88c8eb70f54..bc8e80a86bc 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -23,10 +23,20 @@ static int trace_test_buffer_cpu(struct trace_array *tr, int cpu)
{
struct ring_buffer_event *event;
struct trace_entry *entry;
+ unsigned int loops = 0;
while ((event = ring_buffer_consume(tr->buffer, cpu, NULL))) {
entry = ring_buffer_event_data(event);
+ /*
+ * The ring buffer is a size of trace_buf_size, if
+ * we loop more than the size, there's something wrong
+ * with the ring buffer.
+ */
+ if (loops++ > trace_buf_size) {
+ printk(KERN_CONT ".. bad ring buffer ");
+ goto failed;
+ }
if (!trace_valid_entry(entry)) {
printk(KERN_CONT ".. invalid entry %d ",
entry->type);
@@ -57,11 +67,20 @@ static int trace_test_buffer(struct trace_array *tr, unsigned long *count)
cnt = ring_buffer_entries(tr->buffer);
+ /*
+ * The trace_test_buffer_cpu runs a while loop to consume all data.
+ * If the calling tracer is broken, and is constantly filling
+ * the buffer, this will run forever, and hard lock the box.
+ * We disable the ring buffer while we do this test to prevent
+ * a hard lock up.
+ */
+ tracing_off();
for_each_possible_cpu(cpu) {
ret = trace_test_buffer_cpu(tr, cpu);
if (ret)
break;
}
+ tracing_on();
__raw_spin_unlock(&ftrace_max_lock);
local_irq_restore(flags);