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 /*
  26  * See <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104831> for details.
  27  *
  28  * Until the following patches are backported, Userspace RCU is broken for the
  29  * RISC-V architecture when compiled with GCC.
  30  *
  31  *  - <https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=4990cf84c460f064d6281d0813f20b0ef20c7448>
  32  *  - <https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=4990cf84c460f064d6281d0813f20b0ef20c7448>
  33  *  - <https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=d199d2e56da2379004e7e0457150409c0c99d3e6>
  34  */
  35 #if defined(__GNUC__)
  36 #  error "Implementations of some atomic operations of GCC for RISC-V \
  37           are insufficient for sequential consistency. For this reason \
  38           Userspace RCU is currently marked as 'broken' for RISC-V with \
  39           GCC. However, it is still possible to use other toolchains."
  40 #endif
  41
  42 #ifndef _URCU_ARCH_UATOMIC_RISCV_H
  43 #define _URCU_ARCH_UATOMIC_RISCV_H
  44
  45 #include <urcu/compiler.h>
  46 #include <urcu/system.h>
  47
  48 #ifdef __cplusplus
  49 extern "C" {
  50 #endif
  51
  52 #define UATOMIC_HAS_ATOMIC_BYTE
  53 #define UATOMIC_HAS_ATOMIC_SHORT
  54
  55 #ifdef __cplusplus
  56 }
  57 #endif
  58
  59 #include <urcu/uatomic/generic.h>
  60
  61 #endif /* _URCU_ARCH_UATOMIC_RISCV_H */