// SPDX-License-Identifier: MIT
/*
- * Atomic exchange operations for the RISC-V architecture. Let GCC do it.
+ * Atomic exchange operations for the RISC-V architecture.
+ *
+ * Let the compiler do it.
*/
#ifndef _URCU_ARCH_UATOMIC_RISCV_H
#include <urcu/compiler.h>
#include <urcu/system.h>
+/*
+ * See <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104831> for details.
+ *
+ * Until the following patches are backported, Userspace RCU is broken for the
+ * RISC-V architecture when compiled with GCC.
+ *
+ * - <https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=4990cf84c460f064d6281d0813f20b0ef20c7448>
+ * - <https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=4990cf84c460f064d6281d0813f20b0ef20c7448>
+ * - <https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=d199d2e56da2379004e7e0457150409c0c99d3e6>
+ */
+#ifdef URCU_GCC_VERSION
+# error "Implementations of some atomic operations of GCC for RISC-V are insufficient for sequential consistency. For this reason Userspace RCU is currently marked as 'broken' for RISC-V with GCC. However, it is still possible to use other toolchains."
+#endif
+
#ifdef __cplusplus
extern "C" {
#endif