Add a benchmark to curve25519_kunit.  This brings it in line with the
other crypto KUnit tests and provides an easy way to measure
performance.

Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
 lib/crypto/tests/curve25519_kunit.c | 31 +++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/lib/crypto/tests/curve25519_kunit.c b/lib/crypto/tests/curve25519_kunit.c
index 0d1c46ca74018..355ad79a210d1 100644
--- a/lib/crypto/tests/curve25519_kunit.c
+++ b/lib/crypto/tests/curve25519_kunit.c
@@ -3,10 +3,11 @@
  * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
  */
 
 #include <crypto/curve25519.h>
 #include <kunit/test.h>
+#include <linux/timekeeping.h>
 
 struct curve25519_test_vector {
 	u8 private[CURVE25519_KEY_SIZE];
 	u8 public[CURVE25519_KEY_SIZE];
 	u8 result[CURVE25519_KEY_SIZE];
@@ -1314,13 +1315,43 @@ static void test_curve25519_basepoint(struct kunit *test)
 		KUNIT_EXPECT_MEMEQ_MSG(test, out, out2, CURVE25519_KEY_SIZE,
 				       "in=%*phN", CURVE25519_KEY_SIZE, in);
 	}
 }
 
+static void benchmark_curve25519(struct kunit *test)
+{
+	const u8 *private = curve25519_test_vectors[0].private;
+	const u8 *public = curve25519_test_vectors[0].public;
+	const size_t warmup_niter = 5000;
+	const size_t benchmark_niter = 1024;
+	u8 out[CURVE25519_KEY_SIZE];
+	bool ok = true;
+	u64 t;
+
+	if (!IS_ENABLED(CONFIG_CRYPTO_LIB_BENCHMARK))
+		kunit_skip(test, "not enabled");
+
+	/* Warm-up */
+	for (size_t i = 0; i < warmup_niter; i++)
+		ok &= curve25519(out, private, public);
+
+	/* Benchmark */
+	preempt_disable();
+	t = ktime_get_ns();
+	for (size_t i = 0; i < benchmark_niter; i++)
+		ok &= curve25519(out, private, public);
+	t = ktime_get_ns() - t;
+	preempt_enable();
+	KUNIT_EXPECT_TRUE(test, ok);
+	kunit_info(test, "%llu ops/s",
+		   div64_u64((u64)benchmark_niter * NSEC_PER_SEC, t ?: 1));
+}
+
 static struct kunit_case curve25519_test_cases[] = {
 	KUNIT_CASE(test_curve25519),
 	KUNIT_CASE(test_curve25519_basepoint),
+	KUNIT_CASE(benchmark_curve25519),
 	{},
 };
 
 static struct kunit_suite curve25519_test_suite = {
 	.name = "curve25519",
-- 
2.50.1