[RFC PATCH 6/7] events: Create an trace_get_context_bit()

[Daniel Bristot de Oliveira]

Create a specific function to get the current task context.

Signed-off-by: Daniel Bristot de Oliveira <bris...@redhat.com>
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: Arnaldo Carvalho de Melo <a...@kernel.org>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: Andy Lutomirski <l...@kernel.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: "H. Peter Anvin" <h...@zytor.com>
Cc: "Joel Fernandes (Google)" <j...@joelfernandes.org>
Cc: Jiri Olsa <jo...@redhat.com>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Alexander Shishkin <alexander.shish...@linux.intel.com>
Cc: Tommaso Cucinotta <tommaso.cucino...@santannapisa.it>
Cc: Romulo Silva de Oliveira <romulo.deolive...@ufsc.br>
Cc: Clark Williams <willi...@redhat.com>
Cc: linux-kernel@vger.kernel.org
Cc: x...@kernel.org
---
 kernel/events/internal.h | 37 ++++++++++++++++++++++++++++---------
 1 file changed, 28 insertions(+), 9 deletions(-)

diff --git a/kernel/events/internal.h b/kernel/events/internal.h
index 79c47076700a..241a2318bfdc 100644
--- a/kernel/events/internal.h
+++ b/kernel/events/internal.h
@@ -202,18 +202,37 @@ arch_perf_out_copy_user(void *dst, const void *src, 
unsigned long n)
 
 DEFINE_OUTPUT_COPY(__output_copy_user, arch_perf_out_copy_user)
 
-static inline int get_recursion_context(int *recursion)
+/*
+ * Used for which event context the event is in.
+ *  NMI     = 0
+ *  IRQ     = 1
+ *  SOFTIRQ = 2
+ *  NORMAL  = 3
+ *
+ * See trace_recursive_lock() comment for more details.
+ */
+enum {
+       TRACE_CTX_NMI,
+       TRACE_CTX_IRQ,
+       TRACE_CTX_SOFTIRQ,
+       TRACE_CTX_NORMAL,
+       TRACE_CTX_MAX
+};
+
+static __always_inline int trace_get_context_bit(void)
 {
-       int rctx;
+       unsigned long pc = preempt_count();
 
-       if (unlikely(in_nmi()))
-               rctx = 3;
-       else if (in_irq())
-               rctx = 2;
-       else if (in_softirq())
-               rctx = 1;
+       if (pc & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET))
+               return pc & NMI_MASK ? TRACE_CTX_NMI :
+                       pc & HARDIRQ_MASK ? TRACE_CTX_IRQ : TRACE_CTX_SOFTIRQ;
        else
-               rctx = 0;
+               return TRACE_CTX_NORMAL;
+}
+
+static inline int get_recursion_context(int *recursion)
+{
+       int rctx = trace_get_context_bit();
 
        if (recursion[rctx])
                return -1;
-- 
2.20.1