Patch "tracing/perf: Add interrupt_context_level() helper" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    tracing/perf: Add interrupt_context_level() helper

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     tracing-perf-add-interrupt_context_level-helper.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit e22458140007d732fef998743ee5f9652da738b7
Author: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Date:   Fri Oct 15 15:01:19 2021 -0400

    tracing/perf: Add interrupt_context_level() helper
    
    [ Upstream commit 91ebe8bcbff9d2ff21303e73bf7434f39a98b255 ]
    
    Now that there are three different instances of doing the addition trick
    to the preempt_count() and NMI_MASK, HARDIRQ_MASK and SOFTIRQ_OFFSET
    macros, it deserves a helper function defined in the preempt.h header.
    
    Add the interrupt_context_level() helper and replace the three instances
    that do that logic with it.
    
    Link: https://lore.kernel.org/all/20211015142541.4badd8a9@xxxxxxxxxxxxxxxxxx/
    
    Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
    Stable-dep-of: 87c3a5893e86 ("sched/core: Optimize in_task() and in_interrupt() a bit")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 4d244e295e855..b32e3dabe28bd 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -77,6 +77,27 @@
 /* preempt_count() and related functions, depends on PREEMPT_NEED_RESCHED */
 #include <asm/preempt.h>
 
+/**
+ * interrupt_context_level - return interrupt context level
+ *
+ * Returns the current interrupt context level.
+ *  0 - normal context
+ *  1 - softirq context
+ *  2 - hardirq context
+ *  3 - NMI context
+ */
+static __always_inline unsigned char interrupt_context_level(void)
+{
+	unsigned long pc = preempt_count();
+	unsigned char level = 0;
+
+	level += !!(pc & (NMI_MASK));
+	level += !!(pc & (NMI_MASK | HARDIRQ_MASK));
+	level += !!(pc & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET));
+
+	return level;
+}
+
 #define nmi_count()	(preempt_count() & NMI_MASK)
 #define hardirq_count()	(preempt_count() & HARDIRQ_MASK)
 #ifdef CONFIG_PREEMPT_RT
diff --git a/include/linux/trace_recursion.h b/include/linux/trace_recursion.h
index 00acd7dca7a7d..816d7a0d2aad6 100644
--- a/include/linux/trace_recursion.h
+++ b/include/linux/trace_recursion.h
@@ -116,12 +116,7 @@ enum {
 
 static __always_inline int trace_get_context_bit(void)
 {
-	unsigned long pc = preempt_count();
-	unsigned char bit = 0;
-
-	bit += !!(pc & (NMI_MASK));
-	bit += !!(pc & (NMI_MASK | HARDIRQ_MASK));
-	bit += !!(pc & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET));
+	unsigned char bit = interrupt_context_level();
 
 	return TRACE_CTX_NORMAL - bit;
 }
diff --git a/kernel/events/internal.h b/kernel/events/internal.h
index aa23ffdaf819f..5150d5f84c033 100644
--- a/kernel/events/internal.h
+++ b/kernel/events/internal.h
@@ -210,12 +210,7 @@ DEFINE_OUTPUT_COPY(__output_copy_user, arch_perf_out_copy_user)
 
 static inline int get_recursion_context(int *recursion)
 {
-	unsigned int pc = preempt_count();
-	unsigned char rctx = 0;
-
-	rctx += !!(pc & (NMI_MASK));
-	rctx += !!(pc & (NMI_MASK | HARDIRQ_MASK));
-	rctx += !!(pc & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET));
+	unsigned char rctx = interrupt_context_level();
 
 	if (recursion[rctx])
 		return -1;
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index c3c9960c9f27b..a930a9d7d834d 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -3249,12 +3249,7 @@ static __always_inline int
 trace_recursive_lock(struct ring_buffer_per_cpu *cpu_buffer)
 {
 	unsigned int val = cpu_buffer->current_context;
-	unsigned long pc = preempt_count();
-	int bit = 0;
-
-	bit += !!(pc & (NMI_MASK));
-	bit += !!(pc & (NMI_MASK | HARDIRQ_MASK));
-	bit += !!(pc & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET));
+	int bit = interrupt_context_level();
 
 	bit = RB_CTX_NORMAL - bit;