ARM: 9480/1: entry: expand comment in __switch_tografted

As per discussion between the developers in the mail thread
linked, expand the comment in __switch_to so that readers
of the code understand what is going on.

Suggested-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Linus Walleij <linusw@kernel.org>>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

1 files changed, 38 insertions, 0 deletions

diff --git a/tools/perf/util/trace.h b/tools/perf/util/trace.h
new file mode 100644
index 000000000..fbbcfe6f4
--- /dev/null
+++ b/tools/perf/util/trace.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef UTIL_TRACE_H
+#define UTIL_TRACE_H
+
+#include <stdio.h>  /* for FILE */
+
+enum trace_summary_mode {
+	SUMMARY__NONE = 0,
+	SUMMARY__BY_TOTAL,
+	SUMMARY__BY_THREAD,
+	SUMMARY__BY_CGROUP,
+};
+
+#ifdef HAVE_BPF_SKEL
+
+int trace_prepare_bpf_summary(enum trace_summary_mode mode);
+void trace_start_bpf_summary(void);
+void trace_end_bpf_summary(void);
+int trace_print_bpf_summary(FILE *fp, int max_summary);
+void trace_cleanup_bpf_summary(void);
+
+#else /* !HAVE_BPF_SKEL */
+
+static inline int trace_prepare_bpf_summary(enum trace_summary_mode mode __maybe_unused)
+{
+	return -1;
+}
+static inline void trace_start_bpf_summary(void) {}
+static inline void trace_end_bpf_summary(void) {}
+static inline int trace_print_bpf_summary(FILE *fp __maybe_unused, int max_summary __maybe_unused)
+{
+	return 0;
+}
+static inline void trace_cleanup_bpf_summary(void) {}
+
+#endif /* HAVE_BPF_SKEL */
+
+#endif /* UTIL_TRACE_H */