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@gandalf.local.home/
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Stable-dep-of: 87c3a5893e86 ("sched/core: Optimize in_task() and in_interrupt() a bit")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 4d244e295e855130d253f319e85d78b6b48030ca..b32e3dabe28bd1186d11e19826ea841d1fce2a55 100644 (file)
--- 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 00acd7dca7a7d2e3921fea7fe20be2f4edcebcd7..816d7a0d2aad642159355b3bf99bcd5e66b9e6ea 100644 (file)
--- 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 aa23ffdaf819fb08fd8f1b69701215a697fd3250..5150d5f84c033e5c2e7594db13e3d40f334d4eb3 100644 (file)
--- 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 c3c9960c9f27bf02e8eff1b1fb6d1af577b87429..a930a9d7d834d1b2e2ee33ce86e0acad6ad44ba2 100644 (file)
--- 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;