diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 645231c373c8a5b5684e806a9d13647d1eb3300e..c0d34420a913ded0708a39aaed33a525cdc9e65b 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -480,15 +480,16 @@ do { \
#define trace_printk(fmt, args...) \
do { \
+ static const char *trace_printk_fmt \
+ __attribute__((section("__trace_printk_fmt"))) = \
+ __builtin_constant_p(fmt) ? fmt : NULL; \
+ \
__trace_printk_check_format(fmt, ##args); \
- if (__builtin_constant_p(fmt)) { \
- static const char *trace_printk_fmt \
- __attribute__((section("__trace_printk_fmt"))) = \
- __builtin_constant_p(fmt) ? fmt : NULL; \
\
+ if (__builtin_constant_p(fmt)) \
__trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
- } else \
- __trace_printk(_THIS_IP_, fmt, ##args); \
+ else \
+ __trace_printk(_THIS_IP_, fmt, ##args); \
} while (0)
extern __printf(2, 3)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index ed7b5d1e12f468168178b1a3c144d9736e0b4614..1ab8e35d069b17218e5385a2740bed14ddcf961c 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1498,25 +1498,119 @@ static void __trace_userstack(struct trace_array *tr, unsigned long flags)
#endif /* CONFIG_STACKTRACE */
+/* created for use with alloc_percpu */
+struct trace_buffer_struct {
+ char buffer[TRACE_BUF_SIZE];
+};
+
+static struct trace_buffer_struct *trace_percpu_buffer;
+static struct trace_buffer_struct *trace_percpu_sirq_buffer;
+static struct trace_buffer_struct *trace_percpu_irq_buffer;
+static struct trace_buffer_struct *trace_percpu_nmi_buffer;
+
+/*
+ * The buffer used is dependent on the context. There is a per cpu
+ * buffer for normal context, softirq contex, hard irq context and
+ * for NMI context. Thise allows for lockless recording.
+ *
+ * Note, if the buffers failed to be allocated, then this returns NULL
+ */
+static char *get_trace_buf(void)
+{
+ struct trace_buffer_struct *percpu_buffer;
+ struct trace_buffer_struct *buffer;
+
+ /*
+ * If we have allocated per cpu buffers, then we do not
+ * need to do any locking.
+ */
+ if (in_nmi())
+ percpu_buffer = trace_percpu_nmi_buffer;
+ else if (in_irq())
+ percpu_buffer = trace_percpu_irq_buffer;
+ else if (in_softirq())
+ percpu_buffer = trace_percpu_sirq_buffer;
+ else
+ percpu_buffer = trace_percpu_buffer;
+
+ if (!percpu_buffer)
+ return NULL;
+
+ buffer = per_cpu_ptr(percpu_buffer, smp_processor_id());
+
+ return buffer->buffer;
+}
+
+static int alloc_percpu_trace_buffer(void)
+{
+ struct trace_buffer_struct *buffers;
+ struct trace_buffer_struct *sirq_buffers;
+ struct trace_buffer_struct *irq_buffers;
+ struct trace_buffer_struct *nmi_buffers;
+
+ buffers = alloc_percpu(struct trace_buffer_struct);
+ if (!buffers)
+ goto err_warn;
+
+ sirq_buffers = alloc_percpu(struct trace_buffer_struct);
+ if (!sirq_buffers)
+ goto err_sirq;
+
+ irq_buffers = alloc_percpu(struct trace_buffer_struct);
+ if (!irq_buffers)
+ goto err_irq;
+
+ nmi_buffers = alloc_percpu(struct trace_buffer_struct);
+ if (!nmi_buffers)
+ goto err_nmi;
+
+ trace_percpu_buffer = buffers;
+ trace_percpu_sirq_buffer = sirq_buffers;
+ trace_percpu_irq_buffer = irq_buffers;
+ trace_percpu_nmi_buffer = nmi_buffers;
+
+ return 0;
+
+ err_nmi:
+ free_percpu(irq_buffers);
+ err_irq:
+ free_percpu(sirq_buffers);
+ err_sirq:
+ free_percpu(buffers);
+ err_warn:
+ WARN(1, "Could not allocate percpu trace_printk buffer");
+ return -ENOMEM;
+}
+
+void trace_printk_init_buffers(void)
+{
+ static int buffers_allocated;
+
+ if (buffers_allocated)
+ return;
+
+ if (alloc_percpu_trace_buffer())
+ return;
+
+ pr_info("ftrace: Allocated trace_printk buffers\n");
+
+ buffers_allocated = 1;
+}
+
/**
* trace_vbprintk - write binary msg to tracing buffer
*
*/
int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
{
- static arch_spinlock_t trace_buf_lock =
- (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
- static u32 trace_buf[TRACE_BUF_SIZE];
-
struct ftrace_event_call *call = &event_bprint;
struct ring_buffer_event *event;
struct ring_buffer *buffer;
struct trace_array *tr = &global_trace;
- struct trace_array_cpu *data;
struct bprint_entry *entry;
unsigned long flags;
- int disable;
- int cpu, len = 0, size, pc;
+ char *tbuffer;
+ int len = 0, size, pc;
if (unlikely(tracing_selftest_running || tracing_disabled))
return 0;
@@ -1526,43 +1620,36 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
pc = preempt_count();
preempt_disable_notrace();
- cpu = raw_smp_processor_id();
- data = tr->data[cpu];
- disable = atomic_inc_return(&data->disabled);
- if (unlikely(disable != 1))
+ tbuffer = get_trace_buf();
+ if (!tbuffer) {
+ len = 0;
goto out;
+ }
- /* Lockdep uses trace_printk for lock tracing */
- local_irq_save(flags);
- arch_spin_lock(&trace_buf_lock);
- len = vbin_printf(trace_buf, TRACE_BUF_SIZE, fmt, args);
+ len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
- if (len > TRACE_BUF_SIZE || len < 0)
- goto out_unlock;
+ if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
+ goto out;
+ local_save_flags(flags);
size = sizeof(*entry) + sizeof(u32) * len;
buffer = tr->buffer;
event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
flags, pc);
if (!event)
- goto out_unlock;
+ goto out;
entry = ring_buffer_event_data(event);
entry->ip = ip;
entry->fmt = fmt;
- memcpy(entry->buf, trace_buf, sizeof(u32) * len);
+ memcpy(entry->buf, tbuffer, sizeof(u32) * len);
if (!filter_check_discard(call, entry, buffer, event)) {
ring_buffer_unlock_commit(buffer, event);
ftrace_trace_stack(buffer, flags, 6, pc);
}
-out_unlock:
- arch_spin_unlock(&trace_buf_lock);
- local_irq_restore(flags);
-
out:
- atomic_dec_return(&data->disabled);
preempt_enable_notrace();
unpause_graph_tracing();
@@ -1588,58 +1675,53 @@ int trace_array_printk(struct trace_array *tr,
int trace_array_vprintk(struct trace_array *tr,
unsigned long ip, const char *fmt, va_list args)
{
- static arch_spinlock_t trace_buf_lock = __ARCH_SPIN_LOCK_UNLOCKED;
- static char trace_buf[TRACE_BUF_SIZE];
-
struct ftrace_event_call *call = &event_print;
struct ring_buffer_event *event;
struct ring_buffer *buffer;
- struct trace_array_cpu *data;
- int cpu, len = 0, size, pc;
+ int len = 0, size, pc;
struct print_entry *entry;
- unsigned long irq_flags;
- int disable;
+ unsigned long flags;
+ char *tbuffer;
if (tracing_disabled || tracing_selftest_running)
return 0;
+ /* Don't pollute graph traces with trace_vprintk internals */
+ pause_graph_tracing();
+
pc = preempt_count();
preempt_disable_notrace();
- cpu = raw_smp_processor_id();
- data = tr->data[cpu];
- disable = atomic_inc_return(&data->disabled);
- if (unlikely(disable != 1))
+
+ tbuffer = get_trace_buf();
+ if (!tbuffer) {
+ len = 0;
goto out;
+ }
- pause_graph_tracing();
- raw_local_irq_save(irq_flags);
- arch_spin_lock(&trace_buf_lock);
- len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
+ len = vsnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
+ if (len > TRACE_BUF_SIZE)
+ goto out;
+ local_save_flags(flags);
size = sizeof(*entry) + len + 1;
buffer = tr->buffer;
event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
- irq_flags, pc);
+ flags, pc);
if (!event)
- goto out_unlock;
+ goto out;
entry = ring_buffer_event_data(event);
entry->ip = ip;
- memcpy(&entry->buf, trace_buf, len);
+ memcpy(&entry->buf, tbuffer, len);
entry->buf[len] = '\0';
if (!filter_check_discard(call, entry, buffer, event)) {
ring_buffer_unlock_commit(buffer, event);
- ftrace_trace_stack(buffer, irq_flags, 6, pc);
+ ftrace_trace_stack(buffer, flags, 6, pc);
}
-
- out_unlock:
- arch_spin_unlock(&trace_buf_lock);
- raw_local_irq_restore(irq_flags);
- unpause_graph_tracing();
out:
- atomic_dec_return(&data->disabled);
preempt_enable_notrace();
+ unpause_graph_tracing();
return len;
}
@@ -4955,6 +5037,10 @@ __init static int tracer_alloc_buffers(void)
if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL))
goto out_free_buffer_mask;
+ /* Only allocate trace_printk buffers if a trace_printk exists */
+ if (__stop___trace_bprintk_fmt != __start___trace_bprintk_fmt)
+ trace_printk_init_buffers();
+
/* To save memory, keep the ring buffer size to its minimum */
if (ring_buffer_expanded)
ring_buf_size = trace_buf_size;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 95059f091a242abcfd60bbe9169131e7870e4a2c..f9d85504f04bcc24b16ccf55f8b2d7e38ab723e3 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -826,6 +826,8 @@ extern struct list_head ftrace_events;
extern const char *__start___trace_bprintk_fmt[];
extern const char *__stop___trace_bprintk_fmt[];
+void trace_printk_init_buffers(void);
+
#undef FTRACE_ENTRY
#define FTRACE_ENTRY(call, struct_name, id, tstruct, print, filter) \
extern struct ftrace_event_call \
diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
index 6fd4ffd042f9071fa158400c147de5a55914975d..a9077c1b4ad3f402ecc7580b8c918e0b50db5318 100644
--- a/kernel/trace/trace_printk.c
+++ b/kernel/trace/trace_printk.c
@@ -51,6 +51,10 @@ void hold_module_trace_bprintk_format(const char **start, const char **end)
const char **iter;
char *fmt;
+ /* allocate the trace_printk per cpu buffers */
+ if (start != end)
+ trace_printk_init_buffers();
+
mutex_lock(&btrace_mutex);
for (iter = start; iter < end; iter++) {
struct trace_bprintk_fmt *tb_fmt = lookup_format(*iter);