From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Sun, 3 Sep 2023 14:55:24 +0000 (-0400)
Subject: Tests: Add test for byte/short atomics on addresses which are not word-aligned
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=cac31bf03005c1265ed11df29cf713f626f39c66;p=userspace-rcu.git

Tests: Add test for byte/short atomics on addresses which are not word-aligned

Add a unit test to catch architectures which do not allow byte and short
atomic operations on addresses which are not word aligned.

If an architecture supports byte and short atomic operations, it should
be valid to issue those operations on variables which are not
word-aligned, otherwise the architecture should not define
UATOMIC_HAS_ATOMIC_BYTE nor UATOMIC_HAS_ATOMIC_SHORT.

This should help identify architectures which mistakenly define
UATOMIC_HAS_ATOMIC_BYTE and UATOMIC_HAS_ATOMIC_SHORT.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I13d2f3be41749b018b39499106938b3746c419c1
---

diff --git a/tests/unit/test_uatomic.c b/tests/unit/test_uatomic.c
index 12e0266..d9c70e0 100644
--- a/tests/unit/test_uatomic.c
+++ b/tests/unit/test_uatomic.c
@@ -9,14 +9,18 @@
 
 #define NR_TESTS 17
 
+#define BYTE_PER_LONG	(sizeof(unsigned long) / sizeof(unsigned char))
+#define SHORT_PER_LONG	(sizeof(unsigned long) / sizeof(unsigned short))
+#define INT_PER_LONG	(sizeof(unsigned long) / sizeof(unsigned int))
+
 struct testvals {
 #ifdef UATOMIC_HAS_ATOMIC_BYTE
-	unsigned char c;
+	unsigned char c[BYTE_PER_LONG];
 #endif
 #ifdef UATOMIC_HAS_ATOMIC_SHORT
-	unsigned short s;
+	unsigned short s[SHORT_PER_LONG];
 #endif
-	unsigned int i;
+	unsigned int i[INT_PER_LONG];
 	unsigned long l;
 };
 
@@ -75,25 +79,36 @@ do {						\
 
 int main(void)
 {
-	int nr_run = 2;
+	int nr_run = INT_PER_LONG + 1;
+	unsigned long i;
+
 #ifdef UATOMIC_HAS_ATOMIC_BYTE
-	nr_run += 1;
+	nr_run += BYTE_PER_LONG;
 #endif
 #ifdef UATOMIC_HAS_ATOMIC_SHORT
-	nr_run += 1;
+	nr_run += SHORT_PER_LONG;
 #endif
 
 	plan_tests(nr_run * NR_TESTS);
 #ifdef UATOMIC_HAS_ATOMIC_BYTE
-	diag("Test atomic ops on byte");
-	do_test(&vals.c);
+	for (i = 0; i < BYTE_PER_LONG; i++) {
+		diag("Test atomic ops on byte with %lu byte offset from long alignment",
+			i);
+		do_test(&vals.c[i]);
+	}
 #endif
 #ifdef UATOMIC_HAS_ATOMIC_SHORT
-	diag("Test atomic ops on short");
-	do_test(&vals.s);
+	for (i = 0; i < SHORT_PER_LONG; i++) {
+		diag("Test atomic ops on short with %lu byte offset from long alignment",
+			i * sizeof(unsigned short));
+		do_test(&vals.s[i]);
+	}
 #endif
-	diag("Test atomic ops on int");
-	do_test(&vals.i);
+	for (i = 0; i < INT_PER_LONG; i++) {
+		diag("Test atomic ops on int with %lu byte offset from long alignment",
+			i * sizeof(unsigned int));
+		do_test(&vals.i[i]);
+	}
 	diag("Test atomic ops on long");
 	do_test(&vals.l);