summaryrefslogtreecommitdiff
path: root/kernel/trace/trace.h
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/trace/trace.h')
-rw-r--r--kernel/trace/trace.h68
1 files changed, 33 insertions, 35 deletions
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index f62768288592..53e8ccbae818 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -431,23 +431,8 @@ struct tracer {
* When function tracing occurs, the following steps are made:
* If arch does not support a ftrace feature:
* call internal function (uses INTERNAL bits) which calls...
- * If callback is registered to the "global" list, the list
- * function is called and recursion checks the GLOBAL bits.
- * then this function calls...
* The function callback, which can use the FTRACE bits to
* check for recursion.
- *
- * Now if the arch does not suppport a feature, and it calls
- * the global list function which calls the ftrace callback
- * all three of these steps will do a recursion protection.
- * There's no reason to do one if the previous caller already
- * did. The recursion that we are protecting against will
- * go through the same steps again.
- *
- * To prevent the multiple recursion checks, if a recursion
- * bit is set that is higher than the MAX bit of the current
- * check, then we know that the check was made by the previous
- * caller, and we can skip the current check.
*/
enum {
TRACE_BUFFER_BIT,
@@ -460,12 +445,14 @@ enum {
TRACE_FTRACE_NMI_BIT,
TRACE_FTRACE_IRQ_BIT,
TRACE_FTRACE_SIRQ_BIT,
+ TRACE_FTRACE_TRANSITION_BIT,
- /* INTERNAL_BITs must be greater than FTRACE_BITs */
+ /* Internal use recursion bits */
TRACE_INTERNAL_BIT,
TRACE_INTERNAL_NMI_BIT,
TRACE_INTERNAL_IRQ_BIT,
TRACE_INTERNAL_SIRQ_BIT,
+ TRACE_INTERNAL_TRANSITION_BIT,
TRACE_CONTROL_BIT,
@@ -487,12 +474,18 @@ enum {
#define TRACE_CONTEXT_BITS 4
#define TRACE_FTRACE_START TRACE_FTRACE_BIT
-#define TRACE_FTRACE_MAX ((1 << (TRACE_FTRACE_START + TRACE_CONTEXT_BITS)) - 1)
#define TRACE_LIST_START TRACE_INTERNAL_BIT
-#define TRACE_LIST_MAX ((1 << (TRACE_LIST_START + TRACE_CONTEXT_BITS)) - 1)
-#define TRACE_CONTEXT_MASK TRACE_LIST_MAX
+#define TRACE_CONTEXT_MASK ((1 << (TRACE_LIST_START + TRACE_CONTEXT_BITS)) - 1)
+
+enum {
+ TRACE_CTX_NMI,
+ TRACE_CTX_IRQ,
+ TRACE_CTX_SOFTIRQ,
+ TRACE_CTX_NORMAL,
+ TRACE_CTX_TRANSITION,
+};
static __always_inline int trace_get_context_bit(void)
{
@@ -500,30 +493,36 @@ static __always_inline int trace_get_context_bit(void)
if (in_interrupt()) {
if (in_nmi())
- bit = 0;
+ bit = TRACE_CTX_NMI;
else if (in_irq())
- bit = 1;
+ bit = TRACE_CTX_IRQ;
else
- bit = 2;
+ bit = TRACE_CTX_SOFTIRQ;
} else
- bit = 3;
+ bit = TRACE_CTX_NORMAL;
return bit;
}
-static __always_inline int trace_test_and_set_recursion(int start, int max)
+static __always_inline int trace_test_and_set_recursion(int start)
{
unsigned int val = current->trace_recursion;
int bit;
- /* A previous recursion check was made */
- if ((val & TRACE_CONTEXT_MASK) > max)
- return 0;
-
bit = trace_get_context_bit() + start;
- if (unlikely(val & (1 << bit)))
- return -1;
+ if (unlikely(val & (1 << bit))) {
+ /*
+ * It could be that preempt_count has not been updated during
+ * a switch between contexts. Allow for a single recursion.
+ */
+ bit = start + TRACE_CTX_TRANSITION;
+ if (trace_recursion_test(bit))
+ return -1;
+ trace_recursion_set(bit);
+ barrier();
+ return bit;
+ }
val |= 1 << bit;
current->trace_recursion = val;
@@ -536,9 +535,6 @@ static __always_inline void trace_clear_recursion(int bit)
{
unsigned int val = current->trace_recursion;
- if (!bit)
- return;
-
bit = 1 << bit;
val &= ~bit;
@@ -636,13 +632,15 @@ void update_max_tr_single(struct trace_array *tr,
#endif /* CONFIG_TRACER_MAX_TRACE */
#ifdef CONFIG_STACKTRACE
-void ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags,
+void ftrace_trace_userstack(struct trace_array *tr,
+ struct ring_buffer *buffer, unsigned long flags,
int pc);
void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
int pc);
#else
-static inline void ftrace_trace_userstack(struct ring_buffer *buffer,
+static inline void ftrace_trace_userstack(struct trace_array *tr,
+ struct ring_buffer *buffer,
unsigned long flags, int pc)
{
}