Adding upstream version 15.4.upstream/15.4upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 32 insertions, 0 deletions

diff --git a/src/include/port/atomics/arch-arm.h b/src/include/port/atomics/arch-arm.h
new file mode 100644
index 0000000..9fe8f1b
--- /dev/null
+++ b/src/include/port/atomics/arch-arm.h
@@ -0,0 +1,32 @@
+/*-------------------------------------------------------------------------
+ *
+ * arch-arm.h
+ *	  Atomic operations considerations specific to ARM
+ *
+ * Portions Copyright (c) 2013-2022, PostgreSQL Global Development Group
+ *
+ * NOTES:
+ *
+ * src/include/port/atomics/arch-arm.h
+ *
+ *-------------------------------------------------------------------------
+ */
+
+/* intentionally no include guards, should only be included by atomics.h */
+#ifndef INSIDE_ATOMICS_H
+#error "should be included via atomics.h"
+#endif
+
+/*
+ * 64 bit atomics on ARM32 are implemented using kernel fallbacks and thus
+ * might be slow, so disable entirely. On ARM64 that problem doesn't exist.
+ */
+#if !defined(__aarch64__) && !defined(__aarch64)
+#define PG_DISABLE_64_BIT_ATOMICS
+#else
+/*
+ * Architecture Reference Manual for ARMv8 states aligned read/write to/from
+ * general purpose register is atomic.
+ */
+#define PG_HAVE_8BYTE_SINGLE_COPY_ATOMICITY
+#endif  /* __aarch64__ || __aarch64 */