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, 21 insertions, 0 deletions

diff --git a/tools/perf/perf-sys.h b/tools/perf/perf-sys.h
new file mode 100644
index 000000000..7a2264e1e
--- /dev/null
+++ b/tools/perf/perf-sys.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _PERF_SYS_H
+#define _PERF_SYS_H
+
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/syscall.h>
+#include <linux/compiler.h>
+
+struct perf_event_attr;
+
+static inline int
+sys_perf_event_open(struct perf_event_attr *attr,
+		      pid_t pid, int cpu, int group_fd,
+		      unsigned long flags)
+{
+	return syscall(__NR_perf_event_open, attr, pid, cpu,
+		       group_fd, flags);
+}
+
+#endif /* _PERF_SYS_H */