include/urcu/uatomic/riscv.h

   1 /*
   2  * Atomic exchange operations for the RISC-V architecture. Let GCC do it.
   3  *
   4  * Copyright (c) 2018 Michael Jeanson <mjeanson@efficios.com>
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to
   8  * deal in the Software without restriction, including without limitation the
   9  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
  10  * sell copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  22  * IN THE SOFTWARE.
  23  */
  24
  25 #ifndef _URCU_ARCH_UATOMIC_RISCV_H
  26 #define _URCU_ARCH_UATOMIC_RISCV_H
  27
  28 #include <urcu/compiler.h>
  29 #include <urcu/system.h>
  30
  31 /*
  32  * See <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104831> for details.
  33  *
  34  * Until the following patches are backported, Userspace RCU is broken for the
  35  * RISC-V architecture when compiled with GCC.
  36  *
  37  *  - <https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=4990cf84c460f064d6281d0813f20b0ef20c7448>
  38  *  - <https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=4990cf84c460f064d6281d0813f20b0ef20c7448>
  39  *  - <https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=d199d2e56da2379004e7e0457150409c0c99d3e6>
  40  */
  41 #ifdef URCU_GCC_VERSION
  42 # 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."
  43 #endif
  44
  45 #ifdef __cplusplus
  46 extern "C" {
  47 #endif
  48
  49 #define UATOMIC_HAS_ATOMIC_BYTE
  50 #define UATOMIC_HAS_ATOMIC_SHORT
  51
  52 #ifdef __cplusplus
  53 }
  54 #endif
  55
  56 #include <urcu/uatomic/generic.h>
  57
  58 #endif /* _URCU_ARCH_UATOMIC_RISCV_H */