tracing: arm: arm64: Hide trace events ipi_raise, ipi_entry and ipi_exit

The ipi tracepoints are mostly generic, but the tracepoints ipi_raise,
ipi_entry and ipi_exit are only used by arm and arm64. This means these
trace events are wasting memory in all the other architectures that do not
use them.

Add CONFIG_HAVE_EXTRA_IPI_TRACEPOINTS and have arm and arm64 select it to
enable these trace events. The config makes it easy if other architectures
decide to trace these as well.

Cc: Masami Hiramatsu <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Russell King <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Valentin Schneider <[email protected]>
Cc: Nicolas Pitre <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: https://lore.kernel.org/[email protected]
Signed-off-by: Steven Rostedt (Google) <[email protected]>
Acked-by: Catalin Marinas <[email protected]>

Author: rostedt

arch/arm/Kconfig

@@ -102,6 +102,7 @@ config ARM
 	select HAVE_BUILDTIME_MCOUNT_SORT
 	select HAVE_DEBUG_KMEMLEAK if !XIP_KERNEL
 	select HAVE_DMA_CONTIGUOUS if MMU
+	select HAVE_EXTRA_IPI_TRACEPOINTS
 	select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU
 	select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
 	select HAVE_EFFICIENT_UNALIGNED_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && MMU

arch/arm64/Kconfig

@@ -136,6 +136,7 @@ config ARM64
 	select CPU_PM if (SUSPEND || CPU_IDLE)
 	select CPUMASK_OFFSTACK if NR_CPUS > 256
 	select DCACHE_WORD_ACCESS
+	select HAVE_EXTRA_IPI_TRACEPOINTS
 	select DYNAMIC_FTRACE if FUNCTION_TRACER
 	select DMA_BOUNCE_UNALIGNED_KMALLOC
 	select DMA_DIRECT_REMAP

include/trace/events/ipi.h

@@ -7,34 +7,6 @@
 
 #include <linux/tracepoint.h>
 
-/**
- * ipi_raise - called when a smp cross call is made
- *
- * @mask: mask of recipient CPUs for the IPI
- * @reason: string identifying the IPI purpose
- *
- * It is necessary for @reason to be a static string declared with
- * __tracepoint_string.
- */
-TRACE_EVENT(ipi_raise,
-
-	TP_PROTO(const struct cpumask *mask, const char *reason),
-
-	TP_ARGS(mask, reason),
-
-	TP_STRUCT__entry(
-		__bitmask(target_cpus, nr_cpumask_bits)
-		__field(const char *, reason)
-	),
-
-	TP_fast_assign(
-		__assign_bitmask(target_cpus, cpumask_bits(mask), nr_cpumask_bits);
-		__entry->reason = reason;
-	),
-
-	TP_printk("target_mask=%s (%s)", __get_bitmask(target_cpus), __entry->reason)
-);
-
 TRACE_EVENT(ipi_send_cpu,
 
 	TP_PROTO(const unsigned int cpu, unsigned long callsite, void *callback),
@@ -79,6 +51,35 @@ TRACE_EVENT(ipi_send_cpumask,
 		  __get_cpumask(cpumask), __entry->callsite, __entry->callback)
 );
 
+#ifdef CONFIG_HAVE_EXTRA_IPI_TRACEPOINTS
+/**
+ * ipi_raise - called when a smp cross call is made
+ *
+ * @mask: mask of recipient CPUs for the IPI
+ * @reason: string identifying the IPI purpose
+ *
+ * It is necessary for @reason to be a static string declared with
+ * __tracepoint_string.
+ */
+TRACE_EVENT(ipi_raise,
+
+	TP_PROTO(const struct cpumask *mask, const char *reason),
+
+	TP_ARGS(mask, reason),
+
+	TP_STRUCT__entry(
+		__bitmask(target_cpus, nr_cpumask_bits)
+		__field(const char *, reason)
+	),
+
+	TP_fast_assign(
+		__assign_bitmask(target_cpus, cpumask_bits(mask), nr_cpumask_bits);
+		__entry->reason = reason;
+	),
+
+	TP_printk("target_mask=%s (%s)", __get_bitmask(target_cpus), __entry->reason)
+);
+
 DECLARE_EVENT_CLASS(ipi_handler,
 
 	TP_PROTO(const char *reason),
@@ -127,6 +128,7 @@ DEFINE_EVENT(ipi_handler, ipi_exit,
 
 	TP_ARGS(reason)
 );
+#endif /* CONFIG_HAVE_EXTRA_IPI_TRACEPOINTS */
 
 #endif /* _TRACE_IPI_H */
 

kernel/trace/Kconfig

@@ -53,6 +53,12 @@ config HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 config HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS
 	bool
 
+config HAVE_EXTRA_IPI_TRACEPOINTS
+	bool
+	help
+	 For architectures that use ipi_raise, ipi_entry and ipi_exit
+	 tracepoints.
+
 config HAVE_DYNAMIC_FTRACE_WITH_ARGS
 	bool
 	help